linux/arch/x86/lib/insn-eval.c

1365 lines
38 KiB
C
Raw Normal View History

x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:36 +00:00
/*
* Utility functions for x86 operand and address decoding
*
* Copyright (C) Intel Corporation 2017
*/
#include <linux/kernel.h>
#include <linux/string.h>
x86/insn-eval: Do not BUG on invalid register type We are not in a critical failure path. The invalid register type is caused when trying to decode invalid instruction bytes from a user-space program. Thus, simply print an error message. To prevent this warning from being abused from user space programs, use the rate-limited variant of pr_err(). along with a descriptive prefix. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-11-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:37 +00:00
#include <linux/ratelimit.h>
x86/insn-eval: Add utility function to get segment descriptor The segment descriptor contains information that is relevant to how linear addresses need to be computed. It contains the default size of addresses as well as the base address of the segment. Thus, given a segment selector, we ought to look at segment descriptor to correctly calculate the linear address. In protected mode, the segment selector might indicate a segment descriptor from either the global descriptor table or a local descriptor table. Both cases are considered in this function. This function is a prerequisite for functions in subsequent commits that will obtain the aforementioned attributes of the segment descriptor. Improvements-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-15-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:41 +00:00
#include <linux/mmu_context.h>
#include <asm/desc_defs.h>
#include <asm/desc.h>
x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:36 +00:00
#include <asm/inat.h>
#include <asm/insn.h>
#include <asm/insn-eval.h>
x86/insn-eval: Add utility function to get segment descriptor The segment descriptor contains information that is relevant to how linear addresses need to be computed. It contains the default size of addresses as well as the base address of the segment. Thus, given a segment selector, we ought to look at segment descriptor to correctly calculate the linear address. In protected mode, the segment selector might indicate a segment descriptor from either the global descriptor table or a local descriptor table. Both cases are considered in this function. This function is a prerequisite for functions in subsequent commits that will obtain the aforementioned attributes of the segment descriptor. Improvements-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-15-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:41 +00:00
#include <asm/ldt.h>
x86/insn-eval: Add utility functions to get segment selector When computing a linear address and segmentation is used, we need to know the base address of the segment involved in the computation. In most of the cases, the segment base address will be zero as in USER_DS/USER32_DS. However, it may be possible that a user space program defines its own segments via a local descriptor table. In such a case, the segment base address may not be zero. Thus, the segment base address is needed to calculate correctly the linear address. If running in protected mode, the segment selector to be used when computing a linear address is determined by either any of segment override prefixes in the instruction or inferred from the registers involved in the computation of the effective address; in that order. Also, there are cases when the segment override prefixes shall be ignored (i.e., code segments are always selected by the CS segment register; string instructions always use the ES segment register when using rDI register as operand). In long mode, segment registers are ignored, except for FS and GS. In these two cases, base addresses are obtained from the respective MSRs. For clarity, this process can be split into four steps (and an equal number of functions): determine if segment prefixes overrides can be used; parse the segment override prefixes, and use them if found; if not found or cannot be used, use the default segment registers associated with the operand registers. Once the segment register to use has been identified, read its value to obtain the segment selector. The method to obtain the segment selector depends on several factors. In 32-bit builds, segment selectors are saved into a pt_regs structure when switching to kernel mode. The same is also true for virtual-8086 mode. In 64-bit builds, segmentation is mostly ignored, except when running a program in 32-bit legacy mode. In this case, CS and SS can be obtained from pt_regs. DS, ES, FS and GS can be read directly from the respective segment registers. In order to identify the segment registers, a new set of #defines is introduced. It also includes two special identifiers. One of them indicates when the default segment register associated with instruction operands shall be used. Another one indicates that the contents of the segment register shall be ignored; this identifier is used when in long mode. Improvements-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-14-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:40 +00:00
#include <asm/vm86.h>
x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:36 +00:00
x86/insn-eval: Do not BUG on invalid register type We are not in a critical failure path. The invalid register type is caused when trying to decode invalid instruction bytes from a user-space program. Thus, simply print an error message. To prevent this warning from being abused from user space programs, use the rate-limited variant of pr_err(). along with a descriptive prefix. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-11-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:37 +00:00
#undef pr_fmt
#define pr_fmt(fmt) "insn: " fmt
x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:36 +00:00
enum reg_type {
REG_TYPE_RM = 0,
REG_TYPE_INDEX,
REG_TYPE_BASE,
};
x86/insn-eval: Add utility function to identify string instructions String instructions are special because, in protected mode, the linear address is always obtained via the ES segment register in operands that use the (E)DI register; the DS segment register in operands that use the (E)SI register. Furthermore, segment override prefixes are ignored when calculating a linear address involving the (E)DI register; segment override prefixes can be used when calculating linear addresses involving the (E)SI register. It follows that linear addresses are calculated differently for the case of string instructions. The purpose of this utility function is to identify such instructions for callers to determine a linear address correctly. Note that this function only identifies string instructions; it does not determine what segment register to use in the address computation. That is left to callers. A subsequent commmit introduces a function to determine the segment register to use given the instruction, operands and segment override prefixes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-13-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:39 +00:00
/**
* is_string_insn() - Determine if instruction is a string instruction
* @insn: Instruction containing the opcode to inspect
*
* Returns:
*
* true if the instruction, determined by the opcode, is any of the
* string instructions as defined in the Intel Software Development manual.
* False otherwise.
*/
static bool is_string_insn(struct insn *insn)
{
insn_get_opcode(insn);
/* All string instructions have a 1-byte opcode. */
if (insn->opcode.nbytes != 1)
return false;
switch (insn->opcode.bytes[0]) {
case 0x6c ... 0x6f: /* INS, OUTS */
case 0xa4 ... 0xa7: /* MOVS, CMPS */
case 0xaa ... 0xaf: /* STOS, LODS, SCAS */
return true;
default:
return false;
}
}
x86/insn-eval: Add utility functions to get segment selector When computing a linear address and segmentation is used, we need to know the base address of the segment involved in the computation. In most of the cases, the segment base address will be zero as in USER_DS/USER32_DS. However, it may be possible that a user space program defines its own segments via a local descriptor table. In such a case, the segment base address may not be zero. Thus, the segment base address is needed to calculate correctly the linear address. If running in protected mode, the segment selector to be used when computing a linear address is determined by either any of segment override prefixes in the instruction or inferred from the registers involved in the computation of the effective address; in that order. Also, there are cases when the segment override prefixes shall be ignored (i.e., code segments are always selected by the CS segment register; string instructions always use the ES segment register when using rDI register as operand). In long mode, segment registers are ignored, except for FS and GS. In these two cases, base addresses are obtained from the respective MSRs. For clarity, this process can be split into four steps (and an equal number of functions): determine if segment prefixes overrides can be used; parse the segment override prefixes, and use them if found; if not found or cannot be used, use the default segment registers associated with the operand registers. Once the segment register to use has been identified, read its value to obtain the segment selector. The method to obtain the segment selector depends on several factors. In 32-bit builds, segment selectors are saved into a pt_regs structure when switching to kernel mode. The same is also true for virtual-8086 mode. In 64-bit builds, segmentation is mostly ignored, except when running a program in 32-bit legacy mode. In this case, CS and SS can be obtained from pt_regs. DS, ES, FS and GS can be read directly from the respective segment registers. In order to identify the segment registers, a new set of #defines is introduced. It also includes two special identifiers. One of them indicates when the default segment register associated with instruction operands shall be used. Another one indicates that the contents of the segment register shall be ignored; this identifier is used when in long mode. Improvements-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-14-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:40 +00:00
/**
* get_seg_reg_override_idx() - obtain segment register override index
* @insn: Valid instruction with segment override prefixes
*
* Inspect the instruction prefixes in @insn and find segment overrides, if any.
*
* Returns:
*
* A constant identifying the segment register to use, among CS, SS, DS,
* ES, FS, or GS. INAT_SEG_REG_DEFAULT is returned if no segment override
* prefixes were found.
*
* -EINVAL in case of error.
*/
static int get_seg_reg_override_idx(struct insn *insn)
{
int idx = INAT_SEG_REG_DEFAULT;
int num_overrides = 0, i;
insn_get_prefixes(insn);
/* Look for any segment override prefixes. */
for (i = 0; i < insn->prefixes.nbytes; i++) {
insn_attr_t attr;
attr = inat_get_opcode_attribute(insn->prefixes.bytes[i]);
switch (attr) {
case INAT_MAKE_PREFIX(INAT_PFX_CS):
idx = INAT_SEG_REG_CS;
num_overrides++;
break;
case INAT_MAKE_PREFIX(INAT_PFX_SS):
idx = INAT_SEG_REG_SS;
num_overrides++;
break;
case INAT_MAKE_PREFIX(INAT_PFX_DS):
idx = INAT_SEG_REG_DS;
num_overrides++;
break;
case INAT_MAKE_PREFIX(INAT_PFX_ES):
idx = INAT_SEG_REG_ES;
num_overrides++;
break;
case INAT_MAKE_PREFIX(INAT_PFX_FS):
idx = INAT_SEG_REG_FS;
num_overrides++;
break;
case INAT_MAKE_PREFIX(INAT_PFX_GS):
idx = INAT_SEG_REG_GS;
num_overrides++;
break;
/* No default action needed. */
}
}
/* More than one segment override prefix leads to undefined behavior. */
if (num_overrides > 1)
return -EINVAL;
return idx;
}
/**
* check_seg_overrides() - check if segment override prefixes are allowed
* @insn: Valid instruction with segment override prefixes
* @regoff: Operand offset, in pt_regs, for which the check is performed
*
* For a particular register used in register-indirect addressing, determine if
* segment override prefixes can be used. Specifically, no overrides are allowed
* for rDI if used with a string instruction.
*
* Returns:
*
* True if segment override prefixes can be used with the register indicated
* in @regoff. False if otherwise.
*/
static bool check_seg_overrides(struct insn *insn, int regoff)
{
if (regoff == offsetof(struct pt_regs, di) && is_string_insn(insn))
return false;
return true;
}
/**
* resolve_default_seg() - resolve default segment register index for an operand
* @insn: Instruction with opcode and address size. Must be valid.
* @regs: Register values as seen when entering kernel mode
* @off: Operand offset, in pt_regs, for which resolution is needed
*
* Resolve the default segment register index associated with the instruction
* operand register indicated by @off. Such index is resolved based on defaults
* described in the Intel Software Development Manual.
*
* Returns:
*
* If in protected mode, a constant identifying the segment register to use,
* among CS, SS, ES or DS. If in long mode, INAT_SEG_REG_IGNORE.
*
* -EINVAL in case of error.
*/
static int resolve_default_seg(struct insn *insn, struct pt_regs *regs, int off)
{
if (user_64bit_mode(regs))
return INAT_SEG_REG_IGNORE;
/*
* Resolve the default segment register as described in Section 3.7.4
* of the Intel Software Development Manual Vol. 1:
*
* + DS for all references involving r[ABCD]X, and rSI.
* + If used in a string instruction, ES for rDI. Otherwise, DS.
* + AX, CX and DX are not valid register operands in 16-bit address
* encodings but are valid for 32-bit and 64-bit encodings.
* + -EDOM is reserved to identify for cases in which no register
* is used (i.e., displacement-only addressing). Use DS.
* + SS for rSP or rBP.
* + CS for rIP.
*/
switch (off) {
case offsetof(struct pt_regs, ax):
case offsetof(struct pt_regs, cx):
case offsetof(struct pt_regs, dx):
/* Need insn to verify address size. */
if (insn->addr_bytes == 2)
return -EINVAL;
case -EDOM:
case offsetof(struct pt_regs, bx):
case offsetof(struct pt_regs, si):
return INAT_SEG_REG_DS;
case offsetof(struct pt_regs, di):
if (is_string_insn(insn))
return INAT_SEG_REG_ES;
return INAT_SEG_REG_DS;
case offsetof(struct pt_regs, bp):
case offsetof(struct pt_regs, sp):
return INAT_SEG_REG_SS;
case offsetof(struct pt_regs, ip):
return INAT_SEG_REG_CS;
default:
return -EINVAL;
}
}
/**
* resolve_seg_reg() - obtain segment register index
* @insn: Instruction with operands
* @regs: Register values as seen when entering kernel mode
* @regoff: Operand offset, in pt_regs, used to deterimine segment register
*
* Determine the segment register associated with the operands and, if
* applicable, prefixes and the instruction pointed by @insn.
*
* The segment register associated to an operand used in register-indirect
* addressing depends on:
*
* a) Whether running in long mode (in such a case segments are ignored, except
* if FS or GS are used).
*
* b) Whether segment override prefixes can be used. Certain instructions and
* registers do not allow override prefixes.
*
* c) Whether segment overrides prefixes are found in the instruction prefixes.
*
* d) If there are not segment override prefixes or they cannot be used, the
* default segment register associated with the operand register is used.
*
* The function checks first if segment override prefixes can be used with the
* operand indicated by @regoff. If allowed, obtain such overridden segment
* register index. Lastly, if not prefixes were found or cannot be used, resolve
* the segment register index to use based on the defaults described in the
* Intel documentation. In long mode, all segment register indexes will be
* ignored, except if overrides were found for FS or GS. All these operations
* are done using helper functions.
*
* The operand register, @regoff, is represented as the offset from the base of
* pt_regs.
*
* As stated, the main use of this function is to determine the segment register
* index based on the instruction, its operands and prefixes. Hence, @insn
* must be valid. However, if @regoff indicates rIP, we don't need to inspect
* @insn at all as in this case CS is used in all cases. This case is checked
* before proceeding further.
*
* Please note that this function does not return the value in the segment
* register (i.e., the segment selector) but our defined index. The segment
* selector needs to be obtained using get_segment_selector() and passing the
* segment register index resolved by this function.
*
* Returns:
*
* An index identifying the segment register to use, among CS, SS, DS,
* ES, FS, or GS. INAT_SEG_REG_IGNORE is returned if running in long mode.
*
* -EINVAL in case of error.
*/
static int resolve_seg_reg(struct insn *insn, struct pt_regs *regs, int regoff)
{
int idx;
/*
* In the unlikely event of having to resolve the segment register
* index for rIP, do it first. Segment override prefixes should not
* be used. Hence, it is not necessary to inspect the instruction,
* which may be invalid at this point.
*/
if (regoff == offsetof(struct pt_regs, ip)) {
if (user_64bit_mode(regs))
return INAT_SEG_REG_IGNORE;
else
return INAT_SEG_REG_CS;
}
if (!insn)
return -EINVAL;
if (!check_seg_overrides(insn, regoff))
return resolve_default_seg(insn, regs, regoff);
idx = get_seg_reg_override_idx(insn);
if (idx < 0)
return idx;
if (idx == INAT_SEG_REG_DEFAULT)
return resolve_default_seg(insn, regs, regoff);
/*
* In long mode, segment override prefixes are ignored, except for
* overrides for FS and GS.
*/
if (user_64bit_mode(regs)) {
if (idx != INAT_SEG_REG_FS &&
idx != INAT_SEG_REG_GS)
idx = INAT_SEG_REG_IGNORE;
}
return idx;
}
/**
* get_segment_selector() - obtain segment selector
* @regs: Register values as seen when entering kernel mode
* @seg_reg_idx: Segment register index to use
*
* Obtain the segment selector from any of the CS, SS, DS, ES, FS, GS segment
* registers. In CONFIG_X86_32, the segment is obtained from either pt_regs or
* kernel_vm86_regs as applicable. In CONFIG_X86_64, CS and SS are obtained
* from pt_regs. DS, ES, FS and GS are obtained by reading the actual CPU
* registers. This done for only for completeness as in CONFIG_X86_64 segment
* registers are ignored.
*
* Returns:
*
* Value of the segment selector, including null when running in
* long mode.
*
* -EINVAL on error.
*/
static short get_segment_selector(struct pt_regs *regs, int seg_reg_idx)
{
#ifdef CONFIG_X86_64
unsigned short sel;
switch (seg_reg_idx) {
case INAT_SEG_REG_IGNORE:
return 0;
case INAT_SEG_REG_CS:
return (unsigned short)(regs->cs & 0xffff);
case INAT_SEG_REG_SS:
return (unsigned short)(regs->ss & 0xffff);
case INAT_SEG_REG_DS:
savesegment(ds, sel);
return sel;
case INAT_SEG_REG_ES:
savesegment(es, sel);
return sel;
case INAT_SEG_REG_FS:
savesegment(fs, sel);
return sel;
case INAT_SEG_REG_GS:
savesegment(gs, sel);
return sel;
default:
return -EINVAL;
}
#else /* CONFIG_X86_32 */
struct kernel_vm86_regs *vm86regs = (struct kernel_vm86_regs *)regs;
if (v8086_mode(regs)) {
switch (seg_reg_idx) {
case INAT_SEG_REG_CS:
return (unsigned short)(regs->cs & 0xffff);
case INAT_SEG_REG_SS:
return (unsigned short)(regs->ss & 0xffff);
case INAT_SEG_REG_DS:
return vm86regs->ds;
case INAT_SEG_REG_ES:
return vm86regs->es;
case INAT_SEG_REG_FS:
return vm86regs->fs;
case INAT_SEG_REG_GS:
return vm86regs->gs;
case INAT_SEG_REG_IGNORE:
/* fall through */
default:
return -EINVAL;
}
}
switch (seg_reg_idx) {
case INAT_SEG_REG_CS:
return (unsigned short)(regs->cs & 0xffff);
case INAT_SEG_REG_SS:
return (unsigned short)(regs->ss & 0xffff);
case INAT_SEG_REG_DS:
return (unsigned short)(regs->ds & 0xffff);
case INAT_SEG_REG_ES:
return (unsigned short)(regs->es & 0xffff);
case INAT_SEG_REG_FS:
return (unsigned short)(regs->fs & 0xffff);
case INAT_SEG_REG_GS:
/*
* GS may or may not be in regs as per CONFIG_X86_32_LAZY_GS.
* The macro below takes care of both cases.
*/
return get_user_gs(regs);
case INAT_SEG_REG_IGNORE:
/* fall through */
default:
return -EINVAL;
}
#endif /* CONFIG_X86_64 */
}
x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:36 +00:00
static int get_reg_offset(struct insn *insn, struct pt_regs *regs,
enum reg_type type)
{
int regno = 0;
static const int regoff[] = {
offsetof(struct pt_regs, ax),
offsetof(struct pt_regs, cx),
offsetof(struct pt_regs, dx),
offsetof(struct pt_regs, bx),
offsetof(struct pt_regs, sp),
offsetof(struct pt_regs, bp),
offsetof(struct pt_regs, si),
offsetof(struct pt_regs, di),
#ifdef CONFIG_X86_64
offsetof(struct pt_regs, r8),
offsetof(struct pt_regs, r9),
offsetof(struct pt_regs, r10),
offsetof(struct pt_regs, r11),
offsetof(struct pt_regs, r12),
offsetof(struct pt_regs, r13),
offsetof(struct pt_regs, r14),
offsetof(struct pt_regs, r15),
#endif
};
int nr_registers = ARRAY_SIZE(regoff);
/*
* Don't possibly decode a 32-bit instructions as
* reading a 64-bit-only register.
*/
if (IS_ENABLED(CONFIG_X86_64) && !insn->x86_64)
nr_registers -= 8;
switch (type) {
case REG_TYPE_RM:
regno = X86_MODRM_RM(insn->modrm.value);
x86/insn-eval: Indicate a 32-bit displacement if ModRM.mod is 0 and ModRM.rm is 101b Section 2.2.1.3 of the Intel 64 and IA-32 Architectures Software Developer's Manual volume 2A states that when ModRM.mod is zero and ModRM.rm is 101b, a 32-bit displacement follows the ModRM byte. This means that none of the registers are used in the computation of the effective address. A return value of -EDOM indicates callers that they should not use the value of registers when computing the effective address for the instruction. In long mode, the effective address is given by the 32-bit displacement plus the location of the next instruction. In protected mode, only the displacement is used. The instruction decoder takes care of obtaining the displacement. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-18-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:44 +00:00
/*
* ModRM.mod == 0 and ModRM.rm == 5 means a 32-bit displacement
* follows the ModRM byte.
*/
if (!X86_MODRM_MOD(insn->modrm.value) && regno == 5)
return -EDOM;
x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:36 +00:00
if (X86_REX_B(insn->rex_prefix.value))
regno += 8;
break;
case REG_TYPE_INDEX:
regno = X86_SIB_INDEX(insn->sib.value);
if (X86_REX_X(insn->rex_prefix.value))
regno += 8;
/*
* If ModRM.mod != 3 and SIB.index = 4 the scale*index
* portion of the address computation is null. This is
* true only if REX.X is 0. In such a case, the SIB index
* is used in the address computation.
*/
if (X86_MODRM_MOD(insn->modrm.value) != 3 && regno == 4)
return -EDOM;
break;
case REG_TYPE_BASE:
regno = X86_SIB_BASE(insn->sib.value);
/*
* If ModRM.mod is 0 and SIB.base == 5, the base of the
* register-indirect addressing is 0. In this case, a
* 32-bit displacement follows the SIB byte.
*/
if (!X86_MODRM_MOD(insn->modrm.value) && regno == 5)
return -EDOM;
if (X86_REX_B(insn->rex_prefix.value))
regno += 8;
break;
default:
x86/insn-eval: Do not BUG on invalid register type We are not in a critical failure path. The invalid register type is caused when trying to decode invalid instruction bytes from a user-space program. Thus, simply print an error message. To prevent this warning from being abused from user space programs, use the rate-limited variant of pr_err(). along with a descriptive prefix. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-11-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:37 +00:00
pr_err_ratelimited("invalid register type: %d\n", type);
return -EINVAL;
x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:36 +00:00
}
if (regno >= nr_registers) {
WARN_ONCE(1, "decoded an instruction with an invalid register");
return -EINVAL;
}
return regoff[regno];
}
x86/insn-eval: Add support to resolve 16-bit address encodings Tasks running in virtual-8086 mode, in protected mode with code segment descriptors that specify 16-bit default address sizes via the D bit, or via an address override prefix will use 16-bit addressing form encodings as described in the Intel 64 and IA-32 Architecture Software Developer's Manual Volume 2A Section 2.1.5, Table 2-1. 16-bit addressing encodings differ in several ways from the 32-bit/64-bit addressing form encodings: ModRM.rm points to different registers and, in some cases, effective addresses are indicated by the addition of the value of two registers. Also, there is no support for SIB bytes. Thus, a separate function is needed to parse this form of addressing. Three functions are introduced. get_reg_offset_16() obtains the offset from the base of pt_regs of the registers indicated by the ModRM byte of the address encoding. get_eff_addr_modrm_16() computes the effective address from the value of the register operands. get_addr_ref_16() computes the linear address using the obtained effective address and the base address of the segment. Segment limits are enforced when running in protected mode. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-6-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:50 +00:00
/**
* get_reg_offset_16() - Obtain offset of register indicated by instruction
* @insn: Instruction containing ModRM byte
* @regs: Register values as seen when entering kernel mode
* @offs1: Offset of the first operand register
* @offs2: Offset of the second opeand register, if applicable
*
* Obtain the offset, in pt_regs, of the registers indicated by the ModRM byte
* in @insn. This function is to be used with 16-bit address encodings. The
* @offs1 and @offs2 will be written with the offset of the two registers
* indicated by the instruction. In cases where any of the registers is not
* referenced by the instruction, the value will be set to -EDOM.
*
* Returns:
*
* 0 on success, -EINVAL on error.
*/
static int get_reg_offset_16(struct insn *insn, struct pt_regs *regs,
int *offs1, int *offs2)
{
/*
* 16-bit addressing can use one or two registers. Specifics of
* encodings are given in Table 2-1. "16-Bit Addressing Forms with the
* ModR/M Byte" of the Intel Software Development Manual.
*/
static const int regoff1[] = {
offsetof(struct pt_regs, bx),
offsetof(struct pt_regs, bx),
offsetof(struct pt_regs, bp),
offsetof(struct pt_regs, bp),
offsetof(struct pt_regs, si),
offsetof(struct pt_regs, di),
offsetof(struct pt_regs, bp),
offsetof(struct pt_regs, bx),
};
static const int regoff2[] = {
offsetof(struct pt_regs, si),
offsetof(struct pt_regs, di),
offsetof(struct pt_regs, si),
offsetof(struct pt_regs, di),
-EDOM,
-EDOM,
-EDOM,
-EDOM,
};
if (!offs1 || !offs2)
return -EINVAL;
/* Operand is a register, use the generic function. */
if (X86_MODRM_MOD(insn->modrm.value) == 3) {
*offs1 = insn_get_modrm_rm_off(insn, regs);
*offs2 = -EDOM;
return 0;
}
*offs1 = regoff1[X86_MODRM_RM(insn->modrm.value)];
*offs2 = regoff2[X86_MODRM_RM(insn->modrm.value)];
/*
* If ModRM.mod is 0 and ModRM.rm is 110b, then we use displacement-
* only addressing. This means that no registers are involved in
* computing the effective address. Thus, ensure that the first
* register offset is invalild. The second register offset is already
* invalid under the aforementioned conditions.
*/
if ((X86_MODRM_MOD(insn->modrm.value) == 0) &&
(X86_MODRM_RM(insn->modrm.value) == 6))
*offs1 = -EDOM;
return 0;
}
x86/insn-eval: Add utility function to get segment descriptor The segment descriptor contains information that is relevant to how linear addresses need to be computed. It contains the default size of addresses as well as the base address of the segment. Thus, given a segment selector, we ought to look at segment descriptor to correctly calculate the linear address. In protected mode, the segment selector might indicate a segment descriptor from either the global descriptor table or a local descriptor table. Both cases are considered in this function. This function is a prerequisite for functions in subsequent commits that will obtain the aforementioned attributes of the segment descriptor. Improvements-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-15-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:41 +00:00
/**
* get_desc() - Obtain pointer to a segment descriptor
* @sel: Segment selector
*
* Given a segment selector, obtain a pointer to the segment descriptor.
* Both global and local descriptor tables are supported.
*
* Returns:
*
* Pointer to segment descriptor on success.
*
* NULL on error.
*/
static struct desc_struct *get_desc(unsigned short sel)
{
struct desc_ptr gdt_desc = {0, 0};
unsigned long desc_base;
#ifdef CONFIG_MODIFY_LDT_SYSCALL
if ((sel & SEGMENT_TI_MASK) == SEGMENT_LDT) {
struct desc_struct *desc = NULL;
struct ldt_struct *ldt;
/* Bits [15:3] contain the index of the desired entry. */
sel >>= 3;
mutex_lock(&current->active_mm->context.lock);
ldt = current->active_mm->context.ldt;
if (ldt && sel < ldt->nr_entries)
desc = &ldt->entries[sel];
mutex_unlock(&current->active_mm->context.lock);
return desc;
}
#endif
native_store_gdt(&gdt_desc);
/*
* Segment descriptors have a size of 8 bytes. Thus, the index is
* multiplied by 8 to obtain the memory offset of the desired descriptor
* from the base of the GDT. As bits [15:3] of the segment selector
* contain the index, it can be regarded as multiplied by 8 already.
* All that remains is to clear bits [2:0].
*/
desc_base = sel & ~(SEGMENT_RPL_MASK | SEGMENT_TI_MASK);
if (desc_base > gdt_desc.size)
return NULL;
return (struct desc_struct *)(gdt_desc.address + desc_base);
}
x86/insn-eval: Add utility functions to get segment descriptor base address and limit With segmentation, the base address of the segment is needed to compute a linear address. This base address is obtained from the applicable segment descriptor. Such segment descriptor is referenced from a segment selector. These new functions obtain the segment base and limit of the segment selector indicated by segment register index given as argument. This index is any of the INAT_SEG_REG_* family of #define's. The logic to obtain the segment selector is wrapped in the function get_segment_selector() with the inputs described above. Once the selector is known, the base address is determined. In protected mode, the selector is used to obtain the segment descriptor and then its base address. In long mode, the segment base address is zero except when FS or GS are used. In virtual-8086 mode, the base address is computed as the value of the segment selector shifted 4 positions to the left. In protected mode, segment limits are enforced. Thus, a function to determine the limit of the segment is added. Segment limits are not enforced in long or virtual-8086. For the latter, addresses are limited to 20 bits; address size will be handled when computing the linear address. Improvements-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-16-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:42 +00:00
/**
* insn_get_seg_base() - Obtain base address of segment descriptor.
* @regs: Register values as seen when entering kernel mode
* @seg_reg_idx: Index of the segment register pointing to seg descriptor
*
* Obtain the base address of the segment as indicated by the segment descriptor
* pointed by the segment selector. The segment selector is obtained from the
* input segment register index @seg_reg_idx.
*
* Returns:
*
* In protected mode, base address of the segment. Zero in long mode,
* except when FS or GS are used. In virtual-8086 mode, the segment
* selector shifted 4 bits to the right.
*
* -1L in case of error.
*/
unsigned long insn_get_seg_base(struct pt_regs *regs, int seg_reg_idx)
{
struct desc_struct *desc;
short sel;
sel = get_segment_selector(regs, seg_reg_idx);
if (sel < 0)
return -1L;
if (v8086_mode(regs))
/*
* Base is simply the segment selector shifted 4
* bits to the right.
*/
return (unsigned long)(sel << 4);
if (user_64bit_mode(regs)) {
/*
* Only FS or GS will have a base address, the rest of
* the segments' bases are forced to 0.
*/
unsigned long base;
if (seg_reg_idx == INAT_SEG_REG_FS)
rdmsrl(MSR_FS_BASE, base);
else if (seg_reg_idx == INAT_SEG_REG_GS)
/*
* swapgs was called at the kernel entry point. Thus,
* MSR_KERNEL_GS_BASE will have the user-space GS base.
*/
rdmsrl(MSR_KERNEL_GS_BASE, base);
else
base = 0;
return base;
}
/* In protected mode the segment selector cannot be null. */
if (!sel)
return -1L;
desc = get_desc(sel);
if (!desc)
return -1L;
return get_desc_base(desc);
}
/**
* get_seg_limit() - Obtain the limit of a segment descriptor
* @regs: Register values as seen when entering kernel mode
* @seg_reg_idx: Index of the segment register pointing to seg descriptor
*
* Obtain the limit of the segment as indicated by the segment descriptor
* pointed by the segment selector. The segment selector is obtained from the
* input segment register index @seg_reg_idx.
*
* Returns:
*
* In protected mode, the limit of the segment descriptor in bytes.
* In long mode and virtual-8086 mode, segment limits are not enforced. Thus,
* limit is returned as -1L to imply a limit-less segment.
*
* Zero is returned on error.
*/
static unsigned long get_seg_limit(struct pt_regs *regs, int seg_reg_idx)
{
struct desc_struct *desc;
unsigned long limit;
short sel;
sel = get_segment_selector(regs, seg_reg_idx);
if (sel < 0)
return 0;
if (user_64bit_mode(regs) || v8086_mode(regs))
return -1L;
if (!sel)
return 0;
desc = get_desc(sel);
if (!desc)
return 0;
/*
* If the granularity bit is set, the limit is given in multiples
* of 4096. This also means that the 12 least significant bits are
* not tested when checking the segment limits. In practice,
* this means that the segment ends in (limit << 12) + 0xfff.
*/
limit = get_desc_limit(desc);
if (desc->g)
limit = (limit << 12) + 0xfff;
return limit;
}
x86/insn-eval: Add function to get default params of code segment Obtain the default values of the address and operand sizes as specified in the D and L bits of the the segment descriptor selected by the register CS. The function can be used for both protected and long modes. For virtual-8086 mode, the default address and operand sizes are always 2 bytes. The returned parameters are encoded in a signed 8-bit data type. Auxiliar macros are provided to encode and decode such values. Improvements-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-17-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:43 +00:00
/**
* insn_get_code_seg_params() - Obtain code segment parameters
* @regs: Structure with register values as seen when entering kernel mode
*
* Obtain address and operand sizes of the code segment. It is obtained from the
* selector contained in the CS register in regs. In protected mode, the default
* address is determined by inspecting the L and D bits of the segment
* descriptor. In virtual-8086 mode, the default is always two bytes for both
* address and operand sizes.
*
* Returns:
*
* An int containing ORed-in default parameters on success.
x86/insn-eval: Add function to get default params of code segment Obtain the default values of the address and operand sizes as specified in the D and L bits of the the segment descriptor selected by the register CS. The function can be used for both protected and long modes. For virtual-8086 mode, the default address and operand sizes are always 2 bytes. The returned parameters are encoded in a signed 8-bit data type. Auxiliar macros are provided to encode and decode such values. Improvements-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-17-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:43 +00:00
*
* -EINVAL on error.
*/
int insn_get_code_seg_params(struct pt_regs *regs)
x86/insn-eval: Add function to get default params of code segment Obtain the default values of the address and operand sizes as specified in the D and L bits of the the segment descriptor selected by the register CS. The function can be used for both protected and long modes. For virtual-8086 mode, the default address and operand sizes are always 2 bytes. The returned parameters are encoded in a signed 8-bit data type. Auxiliar macros are provided to encode and decode such values. Improvements-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-17-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:43 +00:00
{
struct desc_struct *desc;
short sel;
if (v8086_mode(regs))
/* Address and operand size are both 16-bit. */
return INSN_CODE_SEG_PARAMS(2, 2);
sel = get_segment_selector(regs, INAT_SEG_REG_CS);
if (sel < 0)
return sel;
desc = get_desc(sel);
if (!desc)
return -EINVAL;
/*
* The most significant byte of the Type field of the segment descriptor
* determines whether a segment contains data or code. If this is a data
* segment, return error.
*/
if (!(desc->type & BIT(3)))
return -EINVAL;
switch ((desc->l << 1) | desc->d) {
case 0: /*
* Legacy mode. CS.L=0, CS.D=0. Address and operand size are
* both 16-bit.
*/
return INSN_CODE_SEG_PARAMS(2, 2);
case 1: /*
* Legacy mode. CS.L=0, CS.D=1. Address and operand size are
* both 32-bit.
*/
return INSN_CODE_SEG_PARAMS(4, 4);
case 2: /*
* IA-32e 64-bit mode. CS.L=1, CS.D=0. Address size is 64-bit;
* operand size is 32-bit.
*/
return INSN_CODE_SEG_PARAMS(4, 8);
case 3: /* Invalid setting. CS.L=1, CS.D=1 */
/* fall through */
default:
return -EINVAL;
}
}
x86/insn-eval: Add a utility function to get register offsets The function get_reg_offset() returns the offset to the register the argument specifies as indicated in an enumeration of type offset. Callers of this function would need the definition of such enumeration. This is not needed. Instead, add helper functions for this purpose. These functions are useful in cases when, for instance, the caller needs to decide whether the operand is a register or a memory location by looking at the rm part of the ModRM byte. As of now, this is the only helper function that is needed. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-12-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:38 +00:00
/**
* insn_get_modrm_rm_off() - Obtain register in r/m part of the ModRM byte
* @insn: Instruction containing the ModRM byte
* @regs: Register values as seen when entering kernel mode
*
* Returns:
*
* The register indicated by the r/m part of the ModRM byte. The
* register is obtained as an offset from the base of pt_regs. In specific
* cases, the returned value can be -EDOM to indicate that the particular value
* of ModRM does not refer to a register and shall be ignored.
*/
int insn_get_modrm_rm_off(struct insn *insn, struct pt_regs *regs)
{
return get_reg_offset(insn, regs, REG_TYPE_RM);
}
x86/insn-eval: Incorporate segment base in linear address computation insn_get_addr_ref() returns the effective address as defined by the section 3.7.5.1 Vol 1 of the Intel 64 and IA-32 Architectures Software Developer's Manual. In order to compute the linear address, we must add to the effective address the segment base address as set in the segment descriptor. The segment descriptor to use depends on the register used as operand and segment override prefixes, if any. In most cases, the segment base address will be 0 if the USER_DS/USER32_DS segment is used or if segmentation is not used. However, the base address is not necessarily zero if a user programs defines its own segments. This is possible by using a local descriptor table. Since the effective address is a signed quantity, the unsigned segment base address is saved in a separate variable and added to the final, unsigned, effective address. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-19-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:45 +00:00
/**
x86/insn-eval: Extend get_seg_base_addr() to also obtain segment limit In protected mode, it is common to want to obtain the limit of a segment along with its base address. This is useful, for instance, to verify that an effective address lies within a segment before computing a linear address. Up to this point, this library only computes linear addresses in long mode. Subsequent patches will include support for protected mode. Support to verify the segment limit will be needed. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509148310-30862-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-27 23:51:38 +00:00
* get_seg_base_limit() - obtain base address and limit of a segment
x86/insn-eval: Incorporate segment base in linear address computation insn_get_addr_ref() returns the effective address as defined by the section 3.7.5.1 Vol 1 of the Intel 64 and IA-32 Architectures Software Developer's Manual. In order to compute the linear address, we must add to the effective address the segment base address as set in the segment descriptor. The segment descriptor to use depends on the register used as operand and segment override prefixes, if any. In most cases, the segment base address will be 0 if the USER_DS/USER32_DS segment is used or if segmentation is not used. However, the base address is not necessarily zero if a user programs defines its own segments. This is possible by using a local descriptor table. Since the effective address is a signed quantity, the unsigned segment base address is saved in a separate variable and added to the final, unsigned, effective address. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-19-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:45 +00:00
* @insn: Instruction. Must be valid.
* @regs: Register values as seen when entering kernel mode
* @regoff: Operand offset, in pt_regs, used to resolve segment descriptor
* @base: Obtained segment base
x86/insn-eval: Extend get_seg_base_addr() to also obtain segment limit In protected mode, it is common to want to obtain the limit of a segment along with its base address. This is useful, for instance, to verify that an effective address lies within a segment before computing a linear address. Up to this point, this library only computes linear addresses in long mode. Subsequent patches will include support for protected mode. Support to verify the segment limit will be needed. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509148310-30862-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-27 23:51:38 +00:00
* @limit: Obtained segment limit
x86/insn-eval: Incorporate segment base in linear address computation insn_get_addr_ref() returns the effective address as defined by the section 3.7.5.1 Vol 1 of the Intel 64 and IA-32 Architectures Software Developer's Manual. In order to compute the linear address, we must add to the effective address the segment base address as set in the segment descriptor. The segment descriptor to use depends on the register used as operand and segment override prefixes, if any. In most cases, the segment base address will be 0 if the USER_DS/USER32_DS segment is used or if segmentation is not used. However, the base address is not necessarily zero if a user programs defines its own segments. This is possible by using a local descriptor table. Since the effective address is a signed quantity, the unsigned segment base address is saved in a separate variable and added to the final, unsigned, effective address. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-19-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:45 +00:00
*
x86/insn-eval: Extend get_seg_base_addr() to also obtain segment limit In protected mode, it is common to want to obtain the limit of a segment along with its base address. This is useful, for instance, to verify that an effective address lies within a segment before computing a linear address. Up to this point, this library only computes linear addresses in long mode. Subsequent patches will include support for protected mode. Support to verify the segment limit will be needed. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509148310-30862-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-27 23:51:38 +00:00
* Obtain the base address and limit of the segment associated with the operand
* @regoff and, if any or allowed, override prefixes in @insn. This function is
x86/insn-eval: Incorporate segment base in linear address computation insn_get_addr_ref() returns the effective address as defined by the section 3.7.5.1 Vol 1 of the Intel 64 and IA-32 Architectures Software Developer's Manual. In order to compute the linear address, we must add to the effective address the segment base address as set in the segment descriptor. The segment descriptor to use depends on the register used as operand and segment override prefixes, if any. In most cases, the segment base address will be 0 if the USER_DS/USER32_DS segment is used or if segmentation is not used. However, the base address is not necessarily zero if a user programs defines its own segments. This is possible by using a local descriptor table. Since the effective address is a signed quantity, the unsigned segment base address is saved in a separate variable and added to the final, unsigned, effective address. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-19-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:45 +00:00
* different from insn_get_seg_base() as the latter does not resolve the segment
x86/insn-eval: Extend get_seg_base_addr() to also obtain segment limit In protected mode, it is common to want to obtain the limit of a segment along with its base address. This is useful, for instance, to verify that an effective address lies within a segment before computing a linear address. Up to this point, this library only computes linear addresses in long mode. Subsequent patches will include support for protected mode. Support to verify the segment limit will be needed. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509148310-30862-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-27 23:51:38 +00:00
* associated with the instruction operand. If a limit is not needed (e.g.,
* when running in long mode), @limit can be NULL.
x86/insn-eval: Incorporate segment base in linear address computation insn_get_addr_ref() returns the effective address as defined by the section 3.7.5.1 Vol 1 of the Intel 64 and IA-32 Architectures Software Developer's Manual. In order to compute the linear address, we must add to the effective address the segment base address as set in the segment descriptor. The segment descriptor to use depends on the register used as operand and segment override prefixes, if any. In most cases, the segment base address will be 0 if the USER_DS/USER32_DS segment is used or if segmentation is not used. However, the base address is not necessarily zero if a user programs defines its own segments. This is possible by using a local descriptor table. Since the effective address is a signed quantity, the unsigned segment base address is saved in a separate variable and added to the final, unsigned, effective address. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-19-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:45 +00:00
*
* Returns:
*
x86/insn-eval: Extend get_seg_base_addr() to also obtain segment limit In protected mode, it is common to want to obtain the limit of a segment along with its base address. This is useful, for instance, to verify that an effective address lies within a segment before computing a linear address. Up to this point, this library only computes linear addresses in long mode. Subsequent patches will include support for protected mode. Support to verify the segment limit will be needed. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509148310-30862-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-27 23:51:38 +00:00
* 0 on success. @base and @limit will contain the base address and of the
* resolved segment, respectively.
x86/insn-eval: Incorporate segment base in linear address computation insn_get_addr_ref() returns the effective address as defined by the section 3.7.5.1 Vol 1 of the Intel 64 and IA-32 Architectures Software Developer's Manual. In order to compute the linear address, we must add to the effective address the segment base address as set in the segment descriptor. The segment descriptor to use depends on the register used as operand and segment override prefixes, if any. In most cases, the segment base address will be 0 if the USER_DS/USER32_DS segment is used or if segmentation is not used. However, the base address is not necessarily zero if a user programs defines its own segments. This is possible by using a local descriptor table. Since the effective address is a signed quantity, the unsigned segment base address is saved in a separate variable and added to the final, unsigned, effective address. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-19-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:45 +00:00
*
* -EINVAL on error.
*/
x86/insn-eval: Extend get_seg_base_addr() to also obtain segment limit In protected mode, it is common to want to obtain the limit of a segment along with its base address. This is useful, for instance, to verify that an effective address lies within a segment before computing a linear address. Up to this point, this library only computes linear addresses in long mode. Subsequent patches will include support for protected mode. Support to verify the segment limit will be needed. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509148310-30862-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-27 23:51:38 +00:00
static int get_seg_base_limit(struct insn *insn, struct pt_regs *regs,
int regoff, unsigned long *base,
unsigned long *limit)
x86/insn-eval: Incorporate segment base in linear address computation insn_get_addr_ref() returns the effective address as defined by the section 3.7.5.1 Vol 1 of the Intel 64 and IA-32 Architectures Software Developer's Manual. In order to compute the linear address, we must add to the effective address the segment base address as set in the segment descriptor. The segment descriptor to use depends on the register used as operand and segment override prefixes, if any. In most cases, the segment base address will be 0 if the USER_DS/USER32_DS segment is used or if segmentation is not used. However, the base address is not necessarily zero if a user programs defines its own segments. This is possible by using a local descriptor table. Since the effective address is a signed quantity, the unsigned segment base address is saved in a separate variable and added to the final, unsigned, effective address. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-19-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:45 +00:00
{
int seg_reg_idx;
if (!base)
return -EINVAL;
seg_reg_idx = resolve_seg_reg(insn, regs, regoff);
if (seg_reg_idx < 0)
return seg_reg_idx;
*base = insn_get_seg_base(regs, seg_reg_idx);
if (*base == -1L)
return -EINVAL;
x86/insn-eval: Extend get_seg_base_addr() to also obtain segment limit In protected mode, it is common to want to obtain the limit of a segment along with its base address. This is useful, for instance, to verify that an effective address lies within a segment before computing a linear address. Up to this point, this library only computes linear addresses in long mode. Subsequent patches will include support for protected mode. Support to verify the segment limit will be needed. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509148310-30862-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-27 23:51:38 +00:00
if (!limit)
return 0;
*limit = get_seg_limit(regs, seg_reg_idx);
if (!(*limit))
return -EINVAL;
x86/insn-eval: Incorporate segment base in linear address computation insn_get_addr_ref() returns the effective address as defined by the section 3.7.5.1 Vol 1 of the Intel 64 and IA-32 Architectures Software Developer's Manual. In order to compute the linear address, we must add to the effective address the segment base address as set in the segment descriptor. The segment descriptor to use depends on the register used as operand and segment override prefixes, if any. In most cases, the segment base address will be 0 if the USER_DS/USER32_DS segment is used or if segmentation is not used. However, the base address is not necessarily zero if a user programs defines its own segments. This is possible by using a local descriptor table. Since the effective address is a signed quantity, the unsigned segment base address is saved in a separate variable and added to the final, unsigned, effective address. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-19-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:45 +00:00
return 0;
}
x86/insn-eval: Compute linear address in several utility functions Computing a linear address involves several steps. The first step is to compute the effective address. This requires determining the addressing mode in use and perform arithmetic operations on the operands. Plus, each addressing mode has special cases that must be handled. Once the effective address is known, the base address of the applicable segment is added to obtain the linear address. Clearly, this is too much work for a single function. Instead, handle each addressing mode in a separate utility function. This improves readability and gives us the opportunity to handler errors better. At the moment, arithmetic to compute the effective address uses 64-byte variables. Thus, limit support to 64-bit addresses. While reworking the function insn_get_addr_ref(), the variable addr_offset is renamed as regoff to reflect its actual use (i.e., offset, from the base of pt_regs, of the register used as operand). Suggested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:46 +00:00
/**
* get_eff_addr_reg() - Obtain effective address from register operand
* @insn: Instruction. Must be valid.
* @regs: Register values as seen when entering kernel mode
* @regoff: Obtained operand offset, in pt_regs, with the effective address
* @eff_addr: Obtained effective address
*
* Obtain the effective address stored in the register operand as indicated by
* the ModRM byte. This function is to be used only with register addressing
* (i.e., ModRM.mod is 3). The effective address is saved in @eff_addr. The
* register operand, as an offset from the base of pt_regs, is saved in @regoff;
* such offset can then be used to resolve the segment associated with the
* operand. This function can be used with any of the supported address sizes
* in x86.
*
* Returns:
*
* 0 on success. @eff_addr will have the effective address stored in the
* operand indicated by ModRM. @regoff will have such operand as an offset from
* the base of pt_regs.
*
* -EINVAL on error.
*/
static int get_eff_addr_reg(struct insn *insn, struct pt_regs *regs,
int *regoff, long *eff_addr)
{
insn_get_modrm(insn);
if (!insn->modrm.nbytes)
return -EINVAL;
if (X86_MODRM_MOD(insn->modrm.value) != 3)
return -EINVAL;
*regoff = get_reg_offset(insn, regs, REG_TYPE_RM);
if (*regoff < 0)
return -EINVAL;
x86/insn-eval: Add support to resolve 32-bit address encodings 32-bit and 64-bit address encodings are identical. Thus, the same logic could be used to resolve the effective address. However, there are two key differences: address size and enforcement of segment limits. If running a 32-bit process on a 64-bit kernel, it is best to perform the address calculation using 32-bit data types. In this manner hardware is used for the arithmetic, including handling of signs and overflows. 32-bit addresses are generally used in protected mode; segment limits are enforced in this mode. This implementation obtains the limit of the segment associated with the instruction operands and prefixes. If the computed address is outside the segment limits, an error is returned. It is also possible to use 32-bit address in long mode and virtual-8086 mode by using an address override prefix. In such cases, segment limits are not enforced. Support to use 32-bit arithmetic is added to the utility functions that compute effective addresses. However, the end result is stored in a variable of type long (which has a width of 8 bytes in 64-bit builds). Hence, once a 32-bit effective address is computed, the 4 most significant bytes are masked out to avoid sign extension. The newly added function get_addr_ref_32() is almost identical to the existing function insn_get_addr_ref() (used for 64-bit addresses). The only difference is that it verifies that the effective address is within the limits of the segment. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-3-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:47 +00:00
/* Ignore bytes that are outside the address size. */
x86/insn-eval: Add support to resolve 16-bit address encodings Tasks running in virtual-8086 mode, in protected mode with code segment descriptors that specify 16-bit default address sizes via the D bit, or via an address override prefix will use 16-bit addressing form encodings as described in the Intel 64 and IA-32 Architecture Software Developer's Manual Volume 2A Section 2.1.5, Table 2-1. 16-bit addressing encodings differ in several ways from the 32-bit/64-bit addressing form encodings: ModRM.rm points to different registers and, in some cases, effective addresses are indicated by the addition of the value of two registers. Also, there is no support for SIB bytes. Thus, a separate function is needed to parse this form of addressing. Three functions are introduced. get_reg_offset_16() obtains the offset from the base of pt_regs of the registers indicated by the ModRM byte of the address encoding. get_eff_addr_modrm_16() computes the effective address from the value of the register operands. get_addr_ref_16() computes the linear address using the obtained effective address and the base address of the segment. Segment limits are enforced when running in protected mode. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-6-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:50 +00:00
if (insn->addr_bytes == 2)
*eff_addr = regs_get_register(regs, *regoff) & 0xffff;
else if (insn->addr_bytes == 4)
x86/insn-eval: Add support to resolve 32-bit address encodings 32-bit and 64-bit address encodings are identical. Thus, the same logic could be used to resolve the effective address. However, there are two key differences: address size and enforcement of segment limits. If running a 32-bit process on a 64-bit kernel, it is best to perform the address calculation using 32-bit data types. In this manner hardware is used for the arithmetic, including handling of signs and overflows. 32-bit addresses are generally used in protected mode; segment limits are enforced in this mode. This implementation obtains the limit of the segment associated with the instruction operands and prefixes. If the computed address is outside the segment limits, an error is returned. It is also possible to use 32-bit address in long mode and virtual-8086 mode by using an address override prefix. In such cases, segment limits are not enforced. Support to use 32-bit arithmetic is added to the utility functions that compute effective addresses. However, the end result is stored in a variable of type long (which has a width of 8 bytes in 64-bit builds). Hence, once a 32-bit effective address is computed, the 4 most significant bytes are masked out to avoid sign extension. The newly added function get_addr_ref_32() is almost identical to the existing function insn_get_addr_ref() (used for 64-bit addresses). The only difference is that it verifies that the effective address is within the limits of the segment. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-3-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:47 +00:00
*eff_addr = regs_get_register(regs, *regoff) & 0xffffffff;
else /* 64-bit address */
*eff_addr = regs_get_register(regs, *regoff);
x86/insn-eval: Compute linear address in several utility functions Computing a linear address involves several steps. The first step is to compute the effective address. This requires determining the addressing mode in use and perform arithmetic operations on the operands. Plus, each addressing mode has special cases that must be handled. Once the effective address is known, the base address of the applicable segment is added to obtain the linear address. Clearly, this is too much work for a single function. Instead, handle each addressing mode in a separate utility function. This improves readability and gives us the opportunity to handler errors better. At the moment, arithmetic to compute the effective address uses 64-byte variables. Thus, limit support to 64-bit addresses. While reworking the function insn_get_addr_ref(), the variable addr_offset is renamed as regoff to reflect its actual use (i.e., offset, from the base of pt_regs, of the register used as operand). Suggested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:46 +00:00
return 0;
}
/**
* get_eff_addr_modrm() - Obtain referenced effective address via ModRM
* @insn: Instruction. Must be valid.
* @regs: Register values as seen when entering kernel mode
* @regoff: Obtained operand offset, in pt_regs, associated with segment
* @eff_addr: Obtained effective address
*
* Obtain the effective address referenced by the ModRM byte of @insn. After
* identifying the registers involved in the register-indirect memory reference,
* its value is obtained from the operands in @regs. The computed address is
* stored @eff_addr. Also, the register operand that indicates the associated
* segment is stored in @regoff, this parameter can later be used to determine
* such segment.
*
* Returns:
*
* 0 on success. @eff_addr will have the referenced effective address. @regoff
* will have a register, as an offset from the base of pt_regs, that can be used
* to resolve the associated segment.
*
* -EINVAL on error.
*/
static int get_eff_addr_modrm(struct insn *insn, struct pt_regs *regs,
int *regoff, long *eff_addr)
{
long tmp;
x86/insn-eval: Add support to resolve 32-bit address encodings 32-bit and 64-bit address encodings are identical. Thus, the same logic could be used to resolve the effective address. However, there are two key differences: address size and enforcement of segment limits. If running a 32-bit process on a 64-bit kernel, it is best to perform the address calculation using 32-bit data types. In this manner hardware is used for the arithmetic, including handling of signs and overflows. 32-bit addresses are generally used in protected mode; segment limits are enforced in this mode. This implementation obtains the limit of the segment associated with the instruction operands and prefixes. If the computed address is outside the segment limits, an error is returned. It is also possible to use 32-bit address in long mode and virtual-8086 mode by using an address override prefix. In such cases, segment limits are not enforced. Support to use 32-bit arithmetic is added to the utility functions that compute effective addresses. However, the end result is stored in a variable of type long (which has a width of 8 bytes in 64-bit builds). Hence, once a 32-bit effective address is computed, the 4 most significant bytes are masked out to avoid sign extension. The newly added function get_addr_ref_32() is almost identical to the existing function insn_get_addr_ref() (used for 64-bit addresses). The only difference is that it verifies that the effective address is within the limits of the segment. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-3-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:47 +00:00
if (insn->addr_bytes != 8 && insn->addr_bytes != 4)
x86/insn-eval: Compute linear address in several utility functions Computing a linear address involves several steps. The first step is to compute the effective address. This requires determining the addressing mode in use and perform arithmetic operations on the operands. Plus, each addressing mode has special cases that must be handled. Once the effective address is known, the base address of the applicable segment is added to obtain the linear address. Clearly, this is too much work for a single function. Instead, handle each addressing mode in a separate utility function. This improves readability and gives us the opportunity to handler errors better. At the moment, arithmetic to compute the effective address uses 64-byte variables. Thus, limit support to 64-bit addresses. While reworking the function insn_get_addr_ref(), the variable addr_offset is renamed as regoff to reflect its actual use (i.e., offset, from the base of pt_regs, of the register used as operand). Suggested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:46 +00:00
return -EINVAL;
insn_get_modrm(insn);
if (!insn->modrm.nbytes)
return -EINVAL;
if (X86_MODRM_MOD(insn->modrm.value) > 2)
return -EINVAL;
*regoff = get_reg_offset(insn, regs, REG_TYPE_RM);
/*
* -EDOM means that we must ignore the address_offset. In such a case,
* in 64-bit mode the effective address relative to the rIP of the
* following instruction.
*/
if (*regoff == -EDOM) {
if (user_64bit_mode(regs))
tmp = regs->ip + insn->length;
else
tmp = 0;
} else if (*regoff < 0) {
return -EINVAL;
} else {
tmp = regs_get_register(regs, *regoff);
}
x86/insn-eval: Add support to resolve 32-bit address encodings 32-bit and 64-bit address encodings are identical. Thus, the same logic could be used to resolve the effective address. However, there are two key differences: address size and enforcement of segment limits. If running a 32-bit process on a 64-bit kernel, it is best to perform the address calculation using 32-bit data types. In this manner hardware is used for the arithmetic, including handling of signs and overflows. 32-bit addresses are generally used in protected mode; segment limits are enforced in this mode. This implementation obtains the limit of the segment associated with the instruction operands and prefixes. If the computed address is outside the segment limits, an error is returned. It is also possible to use 32-bit address in long mode and virtual-8086 mode by using an address override prefix. In such cases, segment limits are not enforced. Support to use 32-bit arithmetic is added to the utility functions that compute effective addresses. However, the end result is stored in a variable of type long (which has a width of 8 bytes in 64-bit builds). Hence, once a 32-bit effective address is computed, the 4 most significant bytes are masked out to avoid sign extension. The newly added function get_addr_ref_32() is almost identical to the existing function insn_get_addr_ref() (used for 64-bit addresses). The only difference is that it verifies that the effective address is within the limits of the segment. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-3-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:47 +00:00
if (insn->addr_bytes == 4) {
int addr32 = (int)(tmp & 0xffffffff) + insn->displacement.value;
*eff_addr = addr32 & 0xffffffff;
} else {
*eff_addr = tmp + insn->displacement.value;
}
x86/insn-eval: Compute linear address in several utility functions Computing a linear address involves several steps. The first step is to compute the effective address. This requires determining the addressing mode in use and perform arithmetic operations on the operands. Plus, each addressing mode has special cases that must be handled. Once the effective address is known, the base address of the applicable segment is added to obtain the linear address. Clearly, this is too much work for a single function. Instead, handle each addressing mode in a separate utility function. This improves readability and gives us the opportunity to handler errors better. At the moment, arithmetic to compute the effective address uses 64-byte variables. Thus, limit support to 64-bit addresses. While reworking the function insn_get_addr_ref(), the variable addr_offset is renamed as regoff to reflect its actual use (i.e., offset, from the base of pt_regs, of the register used as operand). Suggested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:46 +00:00
return 0;
}
x86/insn-eval: Add support to resolve 16-bit address encodings Tasks running in virtual-8086 mode, in protected mode with code segment descriptors that specify 16-bit default address sizes via the D bit, or via an address override prefix will use 16-bit addressing form encodings as described in the Intel 64 and IA-32 Architecture Software Developer's Manual Volume 2A Section 2.1.5, Table 2-1. 16-bit addressing encodings differ in several ways from the 32-bit/64-bit addressing form encodings: ModRM.rm points to different registers and, in some cases, effective addresses are indicated by the addition of the value of two registers. Also, there is no support for SIB bytes. Thus, a separate function is needed to parse this form of addressing. Three functions are introduced. get_reg_offset_16() obtains the offset from the base of pt_regs of the registers indicated by the ModRM byte of the address encoding. get_eff_addr_modrm_16() computes the effective address from the value of the register operands. get_addr_ref_16() computes the linear address using the obtained effective address and the base address of the segment. Segment limits are enforced when running in protected mode. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-6-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:50 +00:00
/**
* get_eff_addr_modrm_16() - Obtain referenced effective address via ModRM
* @insn: Instruction. Must be valid.
* @regs: Register values as seen when entering kernel mode
* @regoff: Obtained operand offset, in pt_regs, associated with segment
* @eff_addr: Obtained effective address
*
* Obtain the 16-bit effective address referenced by the ModRM byte of @insn.
* After identifying the registers involved in the register-indirect memory
* reference, its value is obtained from the operands in @regs. The computed
* address is stored @eff_addr. Also, the register operand that indicates
* the associated segment is stored in @regoff, this parameter can later be used
* to determine such segment.
*
* Returns:
*
* 0 on success. @eff_addr will have the referenced effective address. @regoff
* will have a register, as an offset from the base of pt_regs, that can be used
* to resolve the associated segment.
*
* -EINVAL on error.
*/
static int get_eff_addr_modrm_16(struct insn *insn, struct pt_regs *regs,
int *regoff, short *eff_addr)
{
int addr_offset1, addr_offset2, ret;
short addr1 = 0, addr2 = 0, displacement;
if (insn->addr_bytes != 2)
return -EINVAL;
insn_get_modrm(insn);
if (!insn->modrm.nbytes)
return -EINVAL;
if (X86_MODRM_MOD(insn->modrm.value) > 2)
return -EINVAL;
ret = get_reg_offset_16(insn, regs, &addr_offset1, &addr_offset2);
if (ret < 0)
return -EINVAL;
/*
* Don't fail on invalid offset values. They might be invalid because
* they cannot be used for this particular value of ModRM. Instead, use
* them in the computation only if they contain a valid value.
*/
if (addr_offset1 != -EDOM)
addr1 = regs_get_register(regs, addr_offset1) & 0xffff;
if (addr_offset2 != -EDOM)
addr2 = regs_get_register(regs, addr_offset2) & 0xffff;
displacement = insn->displacement.value & 0xffff;
*eff_addr = addr1 + addr2 + displacement;
/*
* The first operand register could indicate to use of either SS or DS
* registers to obtain the segment selector. The second operand
* register can only indicate the use of DS. Thus, the first operand
* will be used to obtain the segment selector.
*/
*regoff = addr_offset1;
return 0;
}
x86/insn-eval: Compute linear address in several utility functions Computing a linear address involves several steps. The first step is to compute the effective address. This requires determining the addressing mode in use and perform arithmetic operations on the operands. Plus, each addressing mode has special cases that must be handled. Once the effective address is known, the base address of the applicable segment is added to obtain the linear address. Clearly, this is too much work for a single function. Instead, handle each addressing mode in a separate utility function. This improves readability and gives us the opportunity to handler errors better. At the moment, arithmetic to compute the effective address uses 64-byte variables. Thus, limit support to 64-bit addresses. While reworking the function insn_get_addr_ref(), the variable addr_offset is renamed as regoff to reflect its actual use (i.e., offset, from the base of pt_regs, of the register used as operand). Suggested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:46 +00:00
/**
* get_eff_addr_sib() - Obtain referenced effective address via SIB
* @insn: Instruction. Must be valid.
* @regs: Register values as seen when entering kernel mode
* @regoff: Obtained operand offset, in pt_regs, associated with segment
* @eff_addr: Obtained effective address
*
* Obtain the effective address referenced by the SIB byte of @insn. After
* identifying the registers involved in the indexed, register-indirect memory
* reference, its value is obtained from the operands in @regs. The computed
* address is stored @eff_addr. Also, the register operand that indicates the
* associated segment is stored in @regoff, this parameter can later be used to
* determine such segment.
*
* Returns:
*
* 0 on success. @eff_addr will have the referenced effective address.
* @base_offset will have a register, as an offset from the base of pt_regs,
* that can be used to resolve the associated segment.
*
* -EINVAL on error.
*/
static int get_eff_addr_sib(struct insn *insn, struct pt_regs *regs,
int *base_offset, long *eff_addr)
{
long base, indx;
int indx_offset;
x86/insn-eval: Add support to resolve 32-bit address encodings 32-bit and 64-bit address encodings are identical. Thus, the same logic could be used to resolve the effective address. However, there are two key differences: address size and enforcement of segment limits. If running a 32-bit process on a 64-bit kernel, it is best to perform the address calculation using 32-bit data types. In this manner hardware is used for the arithmetic, including handling of signs and overflows. 32-bit addresses are generally used in protected mode; segment limits are enforced in this mode. This implementation obtains the limit of the segment associated with the instruction operands and prefixes. If the computed address is outside the segment limits, an error is returned. It is also possible to use 32-bit address in long mode and virtual-8086 mode by using an address override prefix. In such cases, segment limits are not enforced. Support to use 32-bit arithmetic is added to the utility functions that compute effective addresses. However, the end result is stored in a variable of type long (which has a width of 8 bytes in 64-bit builds). Hence, once a 32-bit effective address is computed, the 4 most significant bytes are masked out to avoid sign extension. The newly added function get_addr_ref_32() is almost identical to the existing function insn_get_addr_ref() (used for 64-bit addresses). The only difference is that it verifies that the effective address is within the limits of the segment. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-3-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:47 +00:00
if (insn->addr_bytes != 8 && insn->addr_bytes != 4)
x86/insn-eval: Compute linear address in several utility functions Computing a linear address involves several steps. The first step is to compute the effective address. This requires determining the addressing mode in use and perform arithmetic operations on the operands. Plus, each addressing mode has special cases that must be handled. Once the effective address is known, the base address of the applicable segment is added to obtain the linear address. Clearly, this is too much work for a single function. Instead, handle each addressing mode in a separate utility function. This improves readability and gives us the opportunity to handler errors better. At the moment, arithmetic to compute the effective address uses 64-byte variables. Thus, limit support to 64-bit addresses. While reworking the function insn_get_addr_ref(), the variable addr_offset is renamed as regoff to reflect its actual use (i.e., offset, from the base of pt_regs, of the register used as operand). Suggested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:46 +00:00
return -EINVAL;
insn_get_modrm(insn);
if (!insn->modrm.nbytes)
return -EINVAL;
if (X86_MODRM_MOD(insn->modrm.value) > 2)
return -EINVAL;
insn_get_sib(insn);
if (!insn->sib.nbytes)
return -EINVAL;
*base_offset = get_reg_offset(insn, regs, REG_TYPE_BASE);
indx_offset = get_reg_offset(insn, regs, REG_TYPE_INDEX);
/*
* Negative values in the base and index offset means an error when
* decoding the SIB byte. Except -EDOM, which means that the registers
* should not be used in the address computation.
*/
if (*base_offset == -EDOM)
base = 0;
else if (*base_offset < 0)
return -EINVAL;
else
base = regs_get_register(regs, *base_offset);
if (indx_offset == -EDOM)
indx = 0;
else if (indx_offset < 0)
return -EINVAL;
else
indx = regs_get_register(regs, indx_offset);
x86/insn-eval: Add support to resolve 32-bit address encodings 32-bit and 64-bit address encodings are identical. Thus, the same logic could be used to resolve the effective address. However, there are two key differences: address size and enforcement of segment limits. If running a 32-bit process on a 64-bit kernel, it is best to perform the address calculation using 32-bit data types. In this manner hardware is used for the arithmetic, including handling of signs and overflows. 32-bit addresses are generally used in protected mode; segment limits are enforced in this mode. This implementation obtains the limit of the segment associated with the instruction operands and prefixes. If the computed address is outside the segment limits, an error is returned. It is also possible to use 32-bit address in long mode and virtual-8086 mode by using an address override prefix. In such cases, segment limits are not enforced. Support to use 32-bit arithmetic is added to the utility functions that compute effective addresses. However, the end result is stored in a variable of type long (which has a width of 8 bytes in 64-bit builds). Hence, once a 32-bit effective address is computed, the 4 most significant bytes are masked out to avoid sign extension. The newly added function get_addr_ref_32() is almost identical to the existing function insn_get_addr_ref() (used for 64-bit addresses). The only difference is that it verifies that the effective address is within the limits of the segment. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-3-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:47 +00:00
if (insn->addr_bytes == 4) {
int addr32, base32, idx32;
base32 = base & 0xffffffff;
idx32 = indx & 0xffffffff;
x86/insn-eval: Compute linear address in several utility functions Computing a linear address involves several steps. The first step is to compute the effective address. This requires determining the addressing mode in use and perform arithmetic operations on the operands. Plus, each addressing mode has special cases that must be handled. Once the effective address is known, the base address of the applicable segment is added to obtain the linear address. Clearly, this is too much work for a single function. Instead, handle each addressing mode in a separate utility function. This improves readability and gives us the opportunity to handler errors better. At the moment, arithmetic to compute the effective address uses 64-byte variables. Thus, limit support to 64-bit addresses. While reworking the function insn_get_addr_ref(), the variable addr_offset is renamed as regoff to reflect its actual use (i.e., offset, from the base of pt_regs, of the register used as operand). Suggested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:46 +00:00
x86/insn-eval: Add support to resolve 32-bit address encodings 32-bit and 64-bit address encodings are identical. Thus, the same logic could be used to resolve the effective address. However, there are two key differences: address size and enforcement of segment limits. If running a 32-bit process on a 64-bit kernel, it is best to perform the address calculation using 32-bit data types. In this manner hardware is used for the arithmetic, including handling of signs and overflows. 32-bit addresses are generally used in protected mode; segment limits are enforced in this mode. This implementation obtains the limit of the segment associated with the instruction operands and prefixes. If the computed address is outside the segment limits, an error is returned. It is also possible to use 32-bit address in long mode and virtual-8086 mode by using an address override prefix. In such cases, segment limits are not enforced. Support to use 32-bit arithmetic is added to the utility functions that compute effective addresses. However, the end result is stored in a variable of type long (which has a width of 8 bytes in 64-bit builds). Hence, once a 32-bit effective address is computed, the 4 most significant bytes are masked out to avoid sign extension. The newly added function get_addr_ref_32() is almost identical to the existing function insn_get_addr_ref() (used for 64-bit addresses). The only difference is that it verifies that the effective address is within the limits of the segment. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-3-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:47 +00:00
addr32 = base32 + idx32 * (1 << X86_SIB_SCALE(insn->sib.value));
addr32 += insn->displacement.value;
*eff_addr = addr32 & 0xffffffff;
} else {
*eff_addr = base + indx * (1 << X86_SIB_SCALE(insn->sib.value));
*eff_addr += insn->displacement.value;
}
x86/insn-eval: Compute linear address in several utility functions Computing a linear address involves several steps. The first step is to compute the effective address. This requires determining the addressing mode in use and perform arithmetic operations on the operands. Plus, each addressing mode has special cases that must be handled. Once the effective address is known, the base address of the applicable segment is added to obtain the linear address. Clearly, this is too much work for a single function. Instead, handle each addressing mode in a separate utility function. This improves readability and gives us the opportunity to handler errors better. At the moment, arithmetic to compute the effective address uses 64-byte variables. Thus, limit support to 64-bit addresses. While reworking the function insn_get_addr_ref(), the variable addr_offset is renamed as regoff to reflect its actual use (i.e., offset, from the base of pt_regs, of the register used as operand). Suggested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:46 +00:00
return 0;
}
x86/insn-eval: Add support to resolve 32-bit address encodings 32-bit and 64-bit address encodings are identical. Thus, the same logic could be used to resolve the effective address. However, there are two key differences: address size and enforcement of segment limits. If running a 32-bit process on a 64-bit kernel, it is best to perform the address calculation using 32-bit data types. In this manner hardware is used for the arithmetic, including handling of signs and overflows. 32-bit addresses are generally used in protected mode; segment limits are enforced in this mode. This implementation obtains the limit of the segment associated with the instruction operands and prefixes. If the computed address is outside the segment limits, an error is returned. It is also possible to use 32-bit address in long mode and virtual-8086 mode by using an address override prefix. In such cases, segment limits are not enforced. Support to use 32-bit arithmetic is added to the utility functions that compute effective addresses. However, the end result is stored in a variable of type long (which has a width of 8 bytes in 64-bit builds). Hence, once a 32-bit effective address is computed, the 4 most significant bytes are masked out to avoid sign extension. The newly added function get_addr_ref_32() is almost identical to the existing function insn_get_addr_ref() (used for 64-bit addresses). The only difference is that it verifies that the effective address is within the limits of the segment. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-3-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:47 +00:00
x86/insn-eval: Add support to resolve 16-bit address encodings Tasks running in virtual-8086 mode, in protected mode with code segment descriptors that specify 16-bit default address sizes via the D bit, or via an address override prefix will use 16-bit addressing form encodings as described in the Intel 64 and IA-32 Architecture Software Developer's Manual Volume 2A Section 2.1.5, Table 2-1. 16-bit addressing encodings differ in several ways from the 32-bit/64-bit addressing form encodings: ModRM.rm points to different registers and, in some cases, effective addresses are indicated by the addition of the value of two registers. Also, there is no support for SIB bytes. Thus, a separate function is needed to parse this form of addressing. Three functions are introduced. get_reg_offset_16() obtains the offset from the base of pt_regs of the registers indicated by the ModRM byte of the address encoding. get_eff_addr_modrm_16() computes the effective address from the value of the register operands. get_addr_ref_16() computes the linear address using the obtained effective address and the base address of the segment. Segment limits are enforced when running in protected mode. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-6-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:50 +00:00
/**
* get_addr_ref_16() - Obtain the 16-bit address referred by instruction
* @insn: Instruction containing ModRM byte and displacement
* @regs: Register values as seen when entering kernel mode
*
* This function is to be used with 16-bit address encodings. Obtain the memory
* address referred by the instruction's ModRM and displacement bytes. Also, the
* segment used as base is determined by either any segment override prefixes in
* @insn or the default segment of the registers involved in the address
* computation. In protected mode, segment limits are enforced.
*
* Returns:
*
* Linear address referenced by the instruction operands on success.
*
* -1L on error.
*/
static void __user *get_addr_ref_16(struct insn *insn, struct pt_regs *regs)
{
unsigned long linear_addr = -1L, seg_base, seg_limit;
int ret, regoff;
short eff_addr;
long tmp;
insn_get_modrm(insn);
insn_get_displacement(insn);
if (insn->addr_bytes != 2)
goto out;
if (X86_MODRM_MOD(insn->modrm.value) == 3) {
ret = get_eff_addr_reg(insn, regs, &regoff, &tmp);
if (ret)
goto out;
eff_addr = tmp;
} else {
ret = get_eff_addr_modrm_16(insn, regs, &regoff, &eff_addr);
if (ret)
goto out;
}
ret = get_seg_base_limit(insn, regs, regoff, &seg_base, &seg_limit);
if (ret)
goto out;
/*
* Before computing the linear address, make sure the effective address
* is within the limits of the segment. In virtual-8086 mode, segment
* limits are not enforced. In such a case, the segment limit is -1L to
* reflect this fact.
*/
if ((unsigned long)(eff_addr & 0xffff) > seg_limit)
goto out;
linear_addr = (unsigned long)(eff_addr & 0xffff) + seg_base;
/* Limit linear address to 20 bits */
if (v8086_mode(regs))
linear_addr &= 0xfffff;
out:
return (void __user *)linear_addr;
}
x86/insn-eval: Add support to resolve 32-bit address encodings 32-bit and 64-bit address encodings are identical. Thus, the same logic could be used to resolve the effective address. However, there are two key differences: address size and enforcement of segment limits. If running a 32-bit process on a 64-bit kernel, it is best to perform the address calculation using 32-bit data types. In this manner hardware is used for the arithmetic, including handling of signs and overflows. 32-bit addresses are generally used in protected mode; segment limits are enforced in this mode. This implementation obtains the limit of the segment associated with the instruction operands and prefixes. If the computed address is outside the segment limits, an error is returned. It is also possible to use 32-bit address in long mode and virtual-8086 mode by using an address override prefix. In such cases, segment limits are not enforced. Support to use 32-bit arithmetic is added to the utility functions that compute effective addresses. However, the end result is stored in a variable of type long (which has a width of 8 bytes in 64-bit builds). Hence, once a 32-bit effective address is computed, the 4 most significant bytes are masked out to avoid sign extension. The newly added function get_addr_ref_32() is almost identical to the existing function insn_get_addr_ref() (used for 64-bit addresses). The only difference is that it verifies that the effective address is within the limits of the segment. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-3-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:47 +00:00
/**
* get_addr_ref_32() - Obtain a 32-bit linear address
* @insn: Instruction with ModRM, SIB bytes and displacement
* @regs: Register values as seen when entering kernel mode
*
* This function is to be used with 32-bit address encodings to obtain the
* linear memory address referred by the instruction's ModRM, SIB,
* displacement bytes and segment base address, as applicable. If in protected
* mode, segment limits are enforced.
*
* Returns:
*
* Linear address referenced by instruction and registers on success.
*
* -1L on error.
*/
static void __user *get_addr_ref_32(struct insn *insn, struct pt_regs *regs)
{
unsigned long linear_addr = -1L, seg_base, seg_limit;
int eff_addr, regoff;
long tmp;
int ret;
if (insn->addr_bytes != 4)
goto out;
if (X86_MODRM_MOD(insn->modrm.value) == 3) {
ret = get_eff_addr_reg(insn, regs, &regoff, &tmp);
if (ret)
goto out;
eff_addr = tmp;
} else {
if (insn->sib.nbytes) {
ret = get_eff_addr_sib(insn, regs, &regoff, &tmp);
if (ret)
goto out;
eff_addr = tmp;
} else {
ret = get_eff_addr_modrm(insn, regs, &regoff, &tmp);
if (ret)
goto out;
eff_addr = tmp;
}
}
ret = get_seg_base_limit(insn, regs, regoff, &seg_base, &seg_limit);
if (ret)
goto out;
/*
* In protected mode, before computing the linear address, make sure
* the effective address is within the limits of the segment.
* 32-bit addresses can be used in long and virtual-8086 modes if an
* address override prefix is used. In such cases, segment limits are
* not enforced. When in virtual-8086 mode, the segment limit is -1L
* to reflect this situation.
*
* After computed, the effective address is treated as an unsigned
* quantity.
*/
if (!user_64bit_mode(regs) && ((unsigned int)eff_addr > seg_limit))
goto out;
x86/insn-eval: Handle 32-bit address encodings in virtual-8086 mode It is possible to utilize 32-bit address encodings in virtual-8086 mode via an address override instruction prefix. However, the range of the effective address is still limited to [0x-0xffff]. In such a case, return error. Also, linear addresses in virtual-8086 mode are limited to 20 bits. Enforce such limit by truncating the most significant bytes of the computed linear address. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-5-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:49 +00:00
/*
* Even though 32-bit address encodings are allowed in virtual-8086
* mode, the address range is still limited to [0x-0xffff].
*/
if (v8086_mode(regs) && (eff_addr & ~0xffff))
goto out;
x86/insn-eval: Add support to resolve 32-bit address encodings 32-bit and 64-bit address encodings are identical. Thus, the same logic could be used to resolve the effective address. However, there are two key differences: address size and enforcement of segment limits. If running a 32-bit process on a 64-bit kernel, it is best to perform the address calculation using 32-bit data types. In this manner hardware is used for the arithmetic, including handling of signs and overflows. 32-bit addresses are generally used in protected mode; segment limits are enforced in this mode. This implementation obtains the limit of the segment associated with the instruction operands and prefixes. If the computed address is outside the segment limits, an error is returned. It is also possible to use 32-bit address in long mode and virtual-8086 mode by using an address override prefix. In such cases, segment limits are not enforced. Support to use 32-bit arithmetic is added to the utility functions that compute effective addresses. However, the end result is stored in a variable of type long (which has a width of 8 bytes in 64-bit builds). Hence, once a 32-bit effective address is computed, the 4 most significant bytes are masked out to avoid sign extension. The newly added function get_addr_ref_32() is almost identical to the existing function insn_get_addr_ref() (used for 64-bit addresses). The only difference is that it verifies that the effective address is within the limits of the segment. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-3-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:47 +00:00
/*
* Data type long could be 64 bits in size. Ensure that our 32-bit
* effective address is not sign-extended when computing the linear
* address.
*/
linear_addr = (unsigned long)(eff_addr & 0xffffffff) + seg_base;
x86/insn-eval: Handle 32-bit address encodings in virtual-8086 mode It is possible to utilize 32-bit address encodings in virtual-8086 mode via an address override instruction prefix. However, the range of the effective address is still limited to [0x-0xffff]. In such a case, return error. Also, linear addresses in virtual-8086 mode are limited to 20 bits. Enforce such limit by truncating the most significant bytes of the computed linear address. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-5-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:49 +00:00
/* Limit linear address to 20 bits */
if (v8086_mode(regs))
linear_addr &= 0xfffff;
x86/insn-eval: Add support to resolve 32-bit address encodings 32-bit and 64-bit address encodings are identical. Thus, the same logic could be used to resolve the effective address. However, there are two key differences: address size and enforcement of segment limits. If running a 32-bit process on a 64-bit kernel, it is best to perform the address calculation using 32-bit data types. In this manner hardware is used for the arithmetic, including handling of signs and overflows. 32-bit addresses are generally used in protected mode; segment limits are enforced in this mode. This implementation obtains the limit of the segment associated with the instruction operands and prefixes. If the computed address is outside the segment limits, an error is returned. It is also possible to use 32-bit address in long mode and virtual-8086 mode by using an address override prefix. In such cases, segment limits are not enforced. Support to use 32-bit arithmetic is added to the utility functions that compute effective addresses. However, the end result is stored in a variable of type long (which has a width of 8 bytes in 64-bit builds). Hence, once a 32-bit effective address is computed, the 4 most significant bytes are masked out to avoid sign extension. The newly added function get_addr_ref_32() is almost identical to the existing function insn_get_addr_ref() (used for 64-bit addresses). The only difference is that it verifies that the effective address is within the limits of the segment. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-3-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:47 +00:00
out:
return (void __user *)linear_addr;
}
x86/insn-eval: Add wrapper function for 32 and 64-bit addresses The function insn_get_addr_ref() is capable of handling only 64-bit addresses. A previous commit introduced a function to handle 32-bit addresses. Invoke these two functions from a third wrapper function that calls the appropriate routine based on the address size specified in the instruction structure (obtained by looking at the code segment default address size and the address override prefix, if present). While doing this, rename the original function insn_get_addr_ref() with the more appropriate name get_addr_ref_64(), ensure it is only used for 64-bit addresses. Also, since 64-bit addresses are not possible in 32-bit builds, provide a dummy function such case. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-4-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:48 +00:00
/**
* get_addr_ref_64() - Obtain a 64-bit linear address
* @insn: Instruction struct with ModRM and SIB bytes and displacement
* @regs: Structure with register values as seen when entering kernel mode
*
* This function is to be used with 64-bit address encodings to obtain the
* linear memory address referred by the instruction's ModRM, SIB,
* displacement bytes and segment base address, as applicable.
*
* Returns:
*
* Linear address referenced by instruction and registers on success.
*
* -1L on error.
x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:36 +00:00
*/
x86/insn-eval: Add wrapper function for 32 and 64-bit addresses The function insn_get_addr_ref() is capable of handling only 64-bit addresses. A previous commit introduced a function to handle 32-bit addresses. Invoke these two functions from a third wrapper function that calls the appropriate routine based on the address size specified in the instruction structure (obtained by looking at the code segment default address size and the address override prefix, if present). While doing this, rename the original function insn_get_addr_ref() with the more appropriate name get_addr_ref_64(), ensure it is only used for 64-bit addresses. Also, since 64-bit addresses are not possible in 32-bit builds, provide a dummy function such case. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-4-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:48 +00:00
#ifndef CONFIG_X86_64
static void __user *get_addr_ref_64(struct insn *insn, struct pt_regs *regs)
{
return (void __user *)-1L;
}
#else
static void __user *get_addr_ref_64(struct insn *insn, struct pt_regs *regs)
x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:36 +00:00
{
x86/insn-eval: Incorporate segment base in linear address computation insn_get_addr_ref() returns the effective address as defined by the section 3.7.5.1 Vol 1 of the Intel 64 and IA-32 Architectures Software Developer's Manual. In order to compute the linear address, we must add to the effective address the segment base address as set in the segment descriptor. The segment descriptor to use depends on the register used as operand and segment override prefixes, if any. In most cases, the segment base address will be 0 if the USER_DS/USER32_DS segment is used or if segmentation is not used. However, the base address is not necessarily zero if a user programs defines its own segments. This is possible by using a local descriptor table. Since the effective address is a signed quantity, the unsigned segment base address is saved in a separate variable and added to the final, unsigned, effective address. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-19-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:45 +00:00
unsigned long linear_addr = -1L, seg_base;
x86/insn-eval: Compute linear address in several utility functions Computing a linear address involves several steps. The first step is to compute the effective address. This requires determining the addressing mode in use and perform arithmetic operations on the operands. Plus, each addressing mode has special cases that must be handled. Once the effective address is known, the base address of the applicable segment is added to obtain the linear address. Clearly, this is too much work for a single function. Instead, handle each addressing mode in a separate utility function. This improves readability and gives us the opportunity to handler errors better. At the moment, arithmetic to compute the effective address uses 64-byte variables. Thus, limit support to 64-bit addresses. While reworking the function insn_get_addr_ref(), the variable addr_offset is renamed as regoff to reflect its actual use (i.e., offset, from the base of pt_regs, of the register used as operand). Suggested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:46 +00:00
int regoff, ret;
long eff_addr;
x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:36 +00:00
x86/insn-eval: Add wrapper function for 32 and 64-bit addresses The function insn_get_addr_ref() is capable of handling only 64-bit addresses. A previous commit introduced a function to handle 32-bit addresses. Invoke these two functions from a third wrapper function that calls the appropriate routine based on the address size specified in the instruction structure (obtained by looking at the code segment default address size and the address override prefix, if present). While doing this, rename the original function insn_get_addr_ref() with the more appropriate name get_addr_ref_64(), ensure it is only used for 64-bit addresses. Also, since 64-bit addresses are not possible in 32-bit builds, provide a dummy function such case. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-4-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:48 +00:00
if (insn->addr_bytes != 8)
goto out;
x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:36 +00:00
if (X86_MODRM_MOD(insn->modrm.value) == 3) {
x86/insn-eval: Compute linear address in several utility functions Computing a linear address involves several steps. The first step is to compute the effective address. This requires determining the addressing mode in use and perform arithmetic operations on the operands. Plus, each addressing mode has special cases that must be handled. Once the effective address is known, the base address of the applicable segment is added to obtain the linear address. Clearly, this is too much work for a single function. Instead, handle each addressing mode in a separate utility function. This improves readability and gives us the opportunity to handler errors better. At the moment, arithmetic to compute the effective address uses 64-byte variables. Thus, limit support to 64-bit addresses. While reworking the function insn_get_addr_ref(), the variable addr_offset is renamed as regoff to reflect its actual use (i.e., offset, from the base of pt_regs, of the register used as operand). Suggested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:46 +00:00
ret = get_eff_addr_reg(insn, regs, &regoff, &eff_addr);
if (ret)
x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:36 +00:00
goto out;
} else {
if (insn->sib.nbytes) {
x86/insn-eval: Compute linear address in several utility functions Computing a linear address involves several steps. The first step is to compute the effective address. This requires determining the addressing mode in use and perform arithmetic operations on the operands. Plus, each addressing mode has special cases that must be handled. Once the effective address is known, the base address of the applicable segment is added to obtain the linear address. Clearly, this is too much work for a single function. Instead, handle each addressing mode in a separate utility function. This improves readability and gives us the opportunity to handler errors better. At the moment, arithmetic to compute the effective address uses 64-byte variables. Thus, limit support to 64-bit addresses. While reworking the function insn_get_addr_ref(), the variable addr_offset is renamed as regoff to reflect its actual use (i.e., offset, from the base of pt_regs, of the register used as operand). Suggested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:46 +00:00
ret = get_eff_addr_sib(insn, regs, &regoff, &eff_addr);
if (ret)
x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:36 +00:00
goto out;
} else {
x86/insn-eval: Compute linear address in several utility functions Computing a linear address involves several steps. The first step is to compute the effective address. This requires determining the addressing mode in use and perform arithmetic operations on the operands. Plus, each addressing mode has special cases that must be handled. Once the effective address is known, the base address of the applicable segment is added to obtain the linear address. Clearly, this is too much work for a single function. Instead, handle each addressing mode in a separate utility function. This improves readability and gives us the opportunity to handler errors better. At the moment, arithmetic to compute the effective address uses 64-byte variables. Thus, limit support to 64-bit addresses. While reworking the function insn_get_addr_ref(), the variable addr_offset is renamed as regoff to reflect its actual use (i.e., offset, from the base of pt_regs, of the register used as operand). Suggested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:46 +00:00
ret = get_eff_addr_modrm(insn, regs, &regoff, &eff_addr);
if (ret)
x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:36 +00:00
goto out;
}
}
x86/insn-eval: Compute linear address in several utility functions Computing a linear address involves several steps. The first step is to compute the effective address. This requires determining the addressing mode in use and perform arithmetic operations on the operands. Plus, each addressing mode has special cases that must be handled. Once the effective address is known, the base address of the applicable segment is added to obtain the linear address. Clearly, this is too much work for a single function. Instead, handle each addressing mode in a separate utility function. This improves readability and gives us the opportunity to handler errors better. At the moment, arithmetic to compute the effective address uses 64-byte variables. Thus, limit support to 64-bit addresses. While reworking the function insn_get_addr_ref(), the variable addr_offset is renamed as regoff to reflect its actual use (i.e., offset, from the base of pt_regs, of the register used as operand). Suggested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-2-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:46 +00:00
ret = get_seg_base_limit(insn, regs, regoff, &seg_base, NULL);
x86/insn-eval: Incorporate segment base in linear address computation insn_get_addr_ref() returns the effective address as defined by the section 3.7.5.1 Vol 1 of the Intel 64 and IA-32 Architectures Software Developer's Manual. In order to compute the linear address, we must add to the effective address the segment base address as set in the segment descriptor. The segment descriptor to use depends on the register used as operand and segment override prefixes, if any. In most cases, the segment base address will be 0 if the USER_DS/USER32_DS segment is used or if segmentation is not used. However, the base address is not necessarily zero if a user programs defines its own segments. This is possible by using a local descriptor table. Since the effective address is a signed quantity, the unsigned segment base address is saved in a separate variable and added to the final, unsigned, effective address. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-19-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:45 +00:00
if (ret)
goto out;
linear_addr = (unsigned long)eff_addr + seg_base;
x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-10-27 20:25:36 +00:00
out:
return (void __user *)linear_addr;
}
x86/insn-eval: Add wrapper function for 32 and 64-bit addresses The function insn_get_addr_ref() is capable of handling only 64-bit addresses. A previous commit introduced a function to handle 32-bit addresses. Invoke these two functions from a third wrapper function that calls the appropriate routine based on the address size specified in the instruction structure (obtained by looking at the code segment default address size and the address override prefix, if present). While doing this, rename the original function insn_get_addr_ref() with the more appropriate name get_addr_ref_64(), ensure it is only used for 64-bit addresses. Also, since 64-bit addresses are not possible in 32-bit builds, provide a dummy function such case. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-4-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:48 +00:00
#endif /* CONFIG_X86_64 */
/**
* insn_get_addr_ref() - Obtain the linear address referred by instruction
* @insn: Instruction structure containing ModRM byte and displacement
* @regs: Structure with register values as seen when entering kernel mode
*
* Obtain the linear address referred by the instruction's ModRM, SIB and
* displacement bytes, and segment base, as applicable. In protected mode,
* segment limits are enforced.
*
* Returns:
*
* Linear address referenced by instruction and registers on success.
*
* -1L on error.
*/
void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs)
{
if (!insn || !regs)
return (void __user *)-1L;
switch (insn->addr_bytes) {
x86/insn-eval: Add support to resolve 16-bit address encodings Tasks running in virtual-8086 mode, in protected mode with code segment descriptors that specify 16-bit default address sizes via the D bit, or via an address override prefix will use 16-bit addressing form encodings as described in the Intel 64 and IA-32 Architecture Software Developer's Manual Volume 2A Section 2.1.5, Table 2-1. 16-bit addressing encodings differ in several ways from the 32-bit/64-bit addressing form encodings: ModRM.rm points to different registers and, in some cases, effective addresses are indicated by the addition of the value of two registers. Also, there is no support for SIB bytes. Thus, a separate function is needed to parse this form of addressing. Three functions are introduced. get_reg_offset_16() obtains the offset from the base of pt_regs of the registers indicated by the ModRM byte of the address encoding. get_eff_addr_modrm_16() computes the effective address from the value of the register operands. get_addr_ref_16() computes the linear address using the obtained effective address and the base address of the segment. Segment limits are enforced when running in protected mode. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-6-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:50 +00:00
case 2:
return get_addr_ref_16(insn, regs);
x86/insn-eval: Add wrapper function for 32 and 64-bit addresses The function insn_get_addr_ref() is capable of handling only 64-bit addresses. A previous commit introduced a function to handle 32-bit addresses. Invoke these two functions from a third wrapper function that calls the appropriate routine based on the address size specified in the instruction structure (obtained by looking at the code segment default address size and the address override prefix, if present). While doing this, rename the original function insn_get_addr_ref() with the more appropriate name get_addr_ref_64(), ensure it is only used for 64-bit addresses. Also, since 64-bit addresses are not possible in 32-bit builds, provide a dummy function such case. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-4-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-06 02:27:48 +00:00
case 4:
return get_addr_ref_32(insn, regs);
case 8:
return get_addr_ref_64(insn, regs);
default:
return (void __user *)-1L;
}
}