Commit Graph

9 Commits

Author SHA1 Message Date
Linus Torvalds
4da9f33026 Support for FSGSBASE. Almost 5 years after the first RFC to support it,
this has been brought into a shape which is maintainable and actually
 works.
 
 This final version was done by Sasha Levin who took it up after Intel
 dropped the ball. Sasha discovered that the SGX (sic!) offerings out there
 ship rogue kernel modules enabling FSGSBASE behind the kernels back which
 opens an instantanious unpriviledged root hole.
 
 The FSGSBASE instructions provide a considerable speedup of the context
 switch path and enable user space to write GSBASE without kernel
 interaction. This enablement requires careful handling of the exception
 entries which go through the paranoid entry path as they cannot longer rely
 on the assumption that user GSBASE is positive (as enforced via prctl() on
 non FSGSBASE enabled systemn). All other entries (syscalls, interrupts and
 exceptions) can still just utilize SWAPGS unconditionally when the entry
 comes from user space. Converting these entries to use FSGSBASE has no
 benefit as SWAPGS is only marginally slower than WRGSBASE and locating and
 retrieving the kernel GSBASE value is not a free operation either. The real
 benefit of RD/WRGSBASE is the avoidance of the MSR reads and writes.
 
 The changes come with appropriate selftests and have held up in field
 testing against the (sanitized) Graphene-SGX driver.
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Merge tag 'x86-fsgsbase-2020-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fsgsbase from Thomas Gleixner:
 "Support for FSGSBASE. Almost 5 years after the first RFC to support
  it, this has been brought into a shape which is maintainable and
  actually works.

  This final version was done by Sasha Levin who took it up after Intel
  dropped the ball. Sasha discovered that the SGX (sic!) offerings out
  there ship rogue kernel modules enabling FSGSBASE behind the kernels
  back which opens an instantanious unpriviledged root hole.

  The FSGSBASE instructions provide a considerable speedup of the
  context switch path and enable user space to write GSBASE without
  kernel interaction. This enablement requires careful handling of the
  exception entries which go through the paranoid entry path as they
  can no longer rely on the assumption that user GSBASE is positive (as
  enforced via prctl() on non FSGSBASE enabled systemn).

  All other entries (syscalls, interrupts and exceptions) can still just
  utilize SWAPGS unconditionally when the entry comes from user space.
  Converting these entries to use FSGSBASE has no benefit as SWAPGS is
  only marginally slower than WRGSBASE and locating and retrieving the
  kernel GSBASE value is not a free operation either. The real benefit
  of RD/WRGSBASE is the avoidance of the MSR reads and writes.

  The changes come with appropriate selftests and have held up in field
  testing against the (sanitized) Graphene-SGX driver"

* tag 'x86-fsgsbase-2020-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
  x86/fsgsbase: Fix Xen PV support
  x86/ptrace: Fix 32-bit PTRACE_SETREGS vs fsbase and gsbase
  selftests/x86/fsgsbase: Add a missing memory constraint
  selftests/x86/fsgsbase: Fix a comment in the ptrace_write_gsbase test
  selftests/x86: Add a syscall_arg_fault_64 test for negative GSBASE
  selftests/x86/fsgsbase: Test ptracer-induced GS base write with FSGSBASE
  selftests/x86/fsgsbase: Test GS selector on ptracer-induced GS base write
  Documentation/x86/64: Add documentation for GS/FS addressing mode
  x86/elf: Enumerate kernel FSGSBASE capability in AT_HWCAP2
  x86/cpu: Enable FSGSBASE on 64bit by default and add a chicken bit
  x86/entry/64: Handle FSGSBASE enabled paranoid entry/exit
  x86/entry/64: Introduce the FIND_PERCPU_BASE macro
  x86/entry/64: Switch CR3 before SWAPGS in paranoid entry
  x86/speculation/swapgs: Check FSGSBASE in enabling SWAPGS mitigation
  x86/process/64: Use FSGSBASE instructions on thread copy and ptrace
  x86/process/64: Use FSBSBASE in switch_to() if available
  x86/process/64: Make save_fsgs_for_kvm() ready for FSGSBASE
  x86/fsgsbase/64: Enable FSGSBASE instructions in helper functions
  x86/fsgsbase/64: Add intrinsics for FSGSBASE instructions
  x86/cpu: Add 'unsafe_fsgsbase' to enable CR4.FSGSBASE
  ...
2020-08-04 21:16:22 -07:00
Uros Bizjak
ef19f826ec crypto: x86 - Put back integer parts of include/asm/inst.h
Resolves conflict with the tip tree.

Fixes: d7866e503b ("crypto: x86 - Remove include/asm/inst.h")
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: Borislav Petkov <bp@alien8.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Stephen Rothwell <sfr@canb.auug.org.au>,
CC: "Chang S. Bae" <chang.seok.bae@intel.com>,
CC: Peter Zijlstra <peterz@infradead.org>,
CC: Sasha Levin <sashal@kernel.org>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-07-23 17:34:20 +10:00
Uros Bizjak
d7866e503b crypto: x86 - Remove include/asm/inst.h
Current minimum required version of binutils is 2.23,
which supports PSHUFB, PCLMULQDQ, PEXTRD, AESKEYGENASSIST,
AESIMC, AESENC, AESENCLAST, AESDEC, AESDECLAST and MOVQ
instruction mnemonics.

Substitute macros from include/asm/inst.h with a proper
instruction mnemonics in various assmbly files from
x86/crypto directory, and remove now unneeded file.

The patch was tested by calculating and comparing sha256sum
hashes of stripped object files before and after the patch,
to be sure that executable code didn't change.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: "David S. Miller" <davem@davemloft.net>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: Borislav Petkov <bp@alien8.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-07-16 21:49:07 +10:00
Chang S. Bae
eaad981291 x86/entry/64: Introduce the FIND_PERCPU_BASE macro
GSBASE is used to find per-CPU data in the kernel. But when GSBASE is
unknown, the per-CPU base can be found from the per_cpu_offset table with a
CPU NR.  The CPU NR is extracted from the limit field of the CPUNODE entry
in GDT, or by the RDPID instruction. This is a prerequisite for using
FSGSBASE in the low level entry code.

Also, add the GAS-compatible RDPID macro as binutils 2.23 do not support
it. Support is added in version 2.27.

[ tglx: Massaged changelog ]

Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1557309753-24073-12-git-send-email-chang.seok.bae@intel.com
Link: https://lkml.kernel.org/r/20200528201402.1708239-11-sashal@kernel.org
2020-06-18 15:47:04 +02:00
Greg Kroah-Hartman
b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Jan Beulich
2baad6121e x86, crc32-pclmul: Fix build with older binutils
binutils prior to 2.18 (e.g. the ones found on SLE10) don't support
assembling PEXTRD, so a macro based approach like the one for PCLMULQDQ
in the same file should be used.

This requires making the helper macros capable of recognizing 32-bit
general purpose register operands.

[ hpa: tagging for stable as it is a low risk build fix ]

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/51A6142A02000078000D99D8@nat28.tlf.novell.com
Cc: Alexander Boyko <alexander_boyko@xyratex.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Huang Ying <ying.huang@intel.com>
Cc: <stable@vger.kernel.org> v3.9
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-05-30 16:36:23 -07:00
Huang Ying
62e7bec494 crypto: aesni-intel - Fix another CTR build failure with gas 2.16.1
The previous AES-NI CTR optimization compiling failure gas 2.16.1 fix
introduces another compiling failure by itself. This patch fixes that.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2010-03-24 21:37:57 +08:00
Huang Ying
32cbd7dfce crypto: aesni-intel - Fix CTR optimization build failure with gas 2.16.1
Andrew Morton reported that AES-NI CTR optimization failed to compile
with gas 2.16.1, the error message is as follow:

arch/x86/crypto/aesni-intel_asm.S: Assembler messages:
arch/x86/crypto/aesni-intel_asm.S:752: Error: suffix or operands invalid for `movq'
arch/x86/crypto/aesni-intel_asm.S:753: Error: suffix or operands invalid for `movq'

To fix this, a gas macro is defined to assemble movq with 64bit
general purpose registers and XMM registers. The macro will generate
the raw .byte sequence for needed instructions.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2010-03-13 16:28:42 +08:00
Huang Ying
fd650a6394 x86: Generate .byte code for some new instructions via gas macro
It will take some time for binutils (gas) to support some newly added
instructions, such as SSE4.1 instructions or the AES-NI instructions
found in upcoming Intel CPU.

To make the source code can be compiled by old binutils, .byte code is
used instead of the assembly instruction. But the readability and
flexibility of raw .byte code is not good.

This patch solves the issue of raw .byte code via generating it via
assembly instruction like gas macro. The syntax is as close as
possible to real assembly instruction.

Some helper macros such as MODRM is not a full feature
implementation. It can be extended when necessary.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2009-11-09 13:52:26 -05:00