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6f121e548f
Currently, vdso.so files are prepared and analyzed by a combination of objcopy, nm, some linker script tricks, and some simple ELF parsers in the kernel. Replace all of that with plain C code that runs at build time. All five vdso images now generate .c files that are compiled and linked in to the kernel image. This should cause only one userspace-visible change: the loaded vDSO images are stripped more heavily than they used to be. Everything outside the loadable segment is dropped. In particular, this causes the section table and section name strings to be missing. This should be fine: real dynamic loaders don't load or inspect these tables anyway. The result is roughly equivalent to eu-strip's --strip-sections option. The purpose of this change is to enable the vvar and hpet mappings to be moved to the page following the vDSO load segment. Currently, it is possible for the section table to extend into the page after the load segment, so, if we map it, it risks overlapping the vvar or hpet page. This happens whenever the load segment is just under a multiple of PAGE_SIZE. The only real subtlety here is that the old code had a C file with inline assembler that did 'call VDSO32_vsyscall' and a linker script that defined 'VDSO32_vsyscall = __kernel_vsyscall'. This most likely worked by accident: the linker script entry defines a symbol associated with an address as opposed to an alias for the real dynamic symbol __kernel_vsyscall. That caused ld to relocate the reference at link time instead of leaving an interposable dynamic relocation. Since the VDSO32_vsyscall hack is no longer needed, I now use 'call __kernel_vsyscall', and I added -Bsymbolic to make it work. vdso2c will generate an error and abort the build if the resulting image contains any dynamic relocations, so we won't silently generate bad vdso images. (Dynamic relocations are a problem because nothing will even attempt to relocate the vdso.) Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/2c4fcf45524162a34d87fdda1eb046b2a5cecee7.1399317206.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
374 lines
10 KiB
C
374 lines
10 KiB
C
#ifndef _ASM_X86_ELF_H
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#define _ASM_X86_ELF_H
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/*
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* ELF register definitions..
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*/
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#include <linux/thread_info.h>
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#include <asm/ptrace.h>
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#include <asm/user.h>
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#include <asm/auxvec.h>
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typedef unsigned long elf_greg_t;
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#define ELF_NGREG (sizeof(struct user_regs_struct) / sizeof(elf_greg_t))
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typedef elf_greg_t elf_gregset_t[ELF_NGREG];
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typedef struct user_i387_struct elf_fpregset_t;
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#ifdef __i386__
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typedef struct user_fxsr_struct elf_fpxregset_t;
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#define R_386_NONE 0
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#define R_386_32 1
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#define R_386_PC32 2
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#define R_386_GOT32 3
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#define R_386_PLT32 4
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#define R_386_COPY 5
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#define R_386_GLOB_DAT 6
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#define R_386_JMP_SLOT 7
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#define R_386_RELATIVE 8
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#define R_386_GOTOFF 9
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#define R_386_GOTPC 10
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#define R_386_NUM 11
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/*
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* These are used to set parameters in the core dumps.
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*/
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#define ELF_CLASS ELFCLASS32
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#define ELF_DATA ELFDATA2LSB
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#define ELF_ARCH EM_386
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#else
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/* x86-64 relocation types */
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#define R_X86_64_NONE 0 /* No reloc */
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#define R_X86_64_64 1 /* Direct 64 bit */
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#define R_X86_64_PC32 2 /* PC relative 32 bit signed */
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#define R_X86_64_GOT32 3 /* 32 bit GOT entry */
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#define R_X86_64_PLT32 4 /* 32 bit PLT address */
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#define R_X86_64_COPY 5 /* Copy symbol at runtime */
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#define R_X86_64_GLOB_DAT 6 /* Create GOT entry */
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#define R_X86_64_JUMP_SLOT 7 /* Create PLT entry */
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#define R_X86_64_RELATIVE 8 /* Adjust by program base */
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#define R_X86_64_GOTPCREL 9 /* 32 bit signed pc relative
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offset to GOT */
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#define R_X86_64_32 10 /* Direct 32 bit zero extended */
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#define R_X86_64_32S 11 /* Direct 32 bit sign extended */
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#define R_X86_64_16 12 /* Direct 16 bit zero extended */
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#define R_X86_64_PC16 13 /* 16 bit sign extended pc relative */
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#define R_X86_64_8 14 /* Direct 8 bit sign extended */
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#define R_X86_64_PC8 15 /* 8 bit sign extended pc relative */
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#define R_X86_64_NUM 16
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/*
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* These are used to set parameters in the core dumps.
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*/
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#define ELF_CLASS ELFCLASS64
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#define ELF_DATA ELFDATA2LSB
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#define ELF_ARCH EM_X86_64
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#endif
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#include <asm/vdso.h>
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#ifdef CONFIG_X86_64
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extern unsigned int vdso64_enabled;
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#endif
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#if defined(CONFIG_X86_32) || defined(CONFIG_COMPAT)
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extern unsigned int vdso32_enabled;
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#endif
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/*
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* This is used to ensure we don't load something for the wrong architecture.
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*/
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#define elf_check_arch_ia32(x) \
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(((x)->e_machine == EM_386) || ((x)->e_machine == EM_486))
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#include <asm/processor.h>
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#ifdef CONFIG_X86_32
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#include <asm/desc.h>
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#define elf_check_arch(x) elf_check_arch_ia32(x)
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/* SVR4/i386 ABI (pages 3-31, 3-32) says that when the program starts %edx
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contains a pointer to a function which might be registered using `atexit'.
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This provides a mean for the dynamic linker to call DT_FINI functions for
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shared libraries that have been loaded before the code runs.
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A value of 0 tells we have no such handler.
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We might as well make sure everything else is cleared too (except for %esp),
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just to make things more deterministic.
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*/
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#define ELF_PLAT_INIT(_r, load_addr) \
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do { \
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_r->bx = 0; _r->cx = 0; _r->dx = 0; \
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_r->si = 0; _r->di = 0; _r->bp = 0; \
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_r->ax = 0; \
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} while (0)
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/*
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* regs is struct pt_regs, pr_reg is elf_gregset_t (which is
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* now struct_user_regs, they are different)
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*/
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#define ELF_CORE_COPY_REGS_COMMON(pr_reg, regs) \
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do { \
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pr_reg[0] = regs->bx; \
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pr_reg[1] = regs->cx; \
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pr_reg[2] = regs->dx; \
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pr_reg[3] = regs->si; \
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pr_reg[4] = regs->di; \
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pr_reg[5] = regs->bp; \
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pr_reg[6] = regs->ax; \
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pr_reg[7] = regs->ds & 0xffff; \
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pr_reg[8] = regs->es & 0xffff; \
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pr_reg[9] = regs->fs & 0xffff; \
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pr_reg[11] = regs->orig_ax; \
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pr_reg[12] = regs->ip; \
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pr_reg[13] = regs->cs & 0xffff; \
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pr_reg[14] = regs->flags; \
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pr_reg[15] = regs->sp; \
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pr_reg[16] = regs->ss & 0xffff; \
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} while (0);
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#define ELF_CORE_COPY_REGS(pr_reg, regs) \
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do { \
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ELF_CORE_COPY_REGS_COMMON(pr_reg, regs);\
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pr_reg[10] = get_user_gs(regs); \
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} while (0);
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#define ELF_CORE_COPY_KERNEL_REGS(pr_reg, regs) \
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do { \
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ELF_CORE_COPY_REGS_COMMON(pr_reg, regs);\
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savesegment(gs, pr_reg[10]); \
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} while (0);
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#define ELF_PLATFORM (utsname()->machine)
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#define set_personality_64bit() do { } while (0)
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#else /* CONFIG_X86_32 */
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/*
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* This is used to ensure we don't load something for the wrong architecture.
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*/
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#define elf_check_arch(x) \
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((x)->e_machine == EM_X86_64)
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#define compat_elf_check_arch(x) \
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(elf_check_arch_ia32(x) || (x)->e_machine == EM_X86_64)
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#if __USER32_DS != __USER_DS
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# error "The following code assumes __USER32_DS == __USER_DS"
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#endif
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static inline void elf_common_init(struct thread_struct *t,
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struct pt_regs *regs, const u16 ds)
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{
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regs->ax = regs->bx = regs->cx = regs->dx = 0;
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regs->si = regs->di = regs->bp = 0;
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regs->r8 = regs->r9 = regs->r10 = regs->r11 = 0;
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regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
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t->fs = t->gs = 0;
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t->fsindex = t->gsindex = 0;
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t->ds = t->es = ds;
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}
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#define ELF_PLAT_INIT(_r, load_addr) \
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elf_common_init(¤t->thread, _r, 0)
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#define COMPAT_ELF_PLAT_INIT(regs, load_addr) \
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elf_common_init(¤t->thread, regs, __USER_DS)
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void start_thread_ia32(struct pt_regs *regs, u32 new_ip, u32 new_sp);
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#define compat_start_thread start_thread_ia32
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void set_personality_ia32(bool);
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#define COMPAT_SET_PERSONALITY(ex) \
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set_personality_ia32((ex).e_machine == EM_X86_64)
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#define COMPAT_ELF_PLATFORM ("i686")
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/*
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* regs is struct pt_regs, pr_reg is elf_gregset_t (which is
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* now struct_user_regs, they are different). Assumes current is the process
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* getting dumped.
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*/
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#define ELF_CORE_COPY_REGS(pr_reg, regs) \
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do { \
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unsigned v; \
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(pr_reg)[0] = (regs)->r15; \
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(pr_reg)[1] = (regs)->r14; \
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(pr_reg)[2] = (regs)->r13; \
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(pr_reg)[3] = (regs)->r12; \
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(pr_reg)[4] = (regs)->bp; \
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(pr_reg)[5] = (regs)->bx; \
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(pr_reg)[6] = (regs)->r11; \
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(pr_reg)[7] = (regs)->r10; \
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(pr_reg)[8] = (regs)->r9; \
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(pr_reg)[9] = (regs)->r8; \
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(pr_reg)[10] = (regs)->ax; \
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(pr_reg)[11] = (regs)->cx; \
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(pr_reg)[12] = (regs)->dx; \
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(pr_reg)[13] = (regs)->si; \
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(pr_reg)[14] = (regs)->di; \
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(pr_reg)[15] = (regs)->orig_ax; \
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(pr_reg)[16] = (regs)->ip; \
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(pr_reg)[17] = (regs)->cs; \
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(pr_reg)[18] = (regs)->flags; \
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(pr_reg)[19] = (regs)->sp; \
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(pr_reg)[20] = (regs)->ss; \
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(pr_reg)[21] = current->thread.fs; \
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(pr_reg)[22] = current->thread.gs; \
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asm("movl %%ds,%0" : "=r" (v)); (pr_reg)[23] = v; \
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asm("movl %%es,%0" : "=r" (v)); (pr_reg)[24] = v; \
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asm("movl %%fs,%0" : "=r" (v)); (pr_reg)[25] = v; \
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asm("movl %%gs,%0" : "=r" (v)); (pr_reg)[26] = v; \
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} while (0);
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/* I'm not sure if we can use '-' here */
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#define ELF_PLATFORM ("x86_64")
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extern void set_personality_64bit(void);
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extern unsigned int sysctl_vsyscall32;
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extern int force_personality32;
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#endif /* !CONFIG_X86_32 */
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#define CORE_DUMP_USE_REGSET
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#define ELF_EXEC_PAGESIZE 4096
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/* This is the location that an ET_DYN program is loaded if exec'ed. Typical
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use of this is to invoke "./ld.so someprog" to test out a new version of
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the loader. We need to make sure that it is out of the way of the program
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that it will "exec", and that there is sufficient room for the brk. */
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#define ELF_ET_DYN_BASE (TASK_SIZE / 3 * 2)
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/* This yields a mask that user programs can use to figure out what
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instruction set this CPU supports. This could be done in user space,
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but it's not easy, and we've already done it here. */
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#define ELF_HWCAP (boot_cpu_data.x86_capability[0])
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/* This yields a string that ld.so will use to load implementation
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specific libraries for optimization. This is more specific in
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intent than poking at uname or /proc/cpuinfo.
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For the moment, we have only optimizations for the Intel generations,
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but that could change... */
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#define SET_PERSONALITY(ex) set_personality_64bit()
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/*
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* An executable for which elf_read_implies_exec() returns TRUE will
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* have the READ_IMPLIES_EXEC personality flag set automatically.
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*/
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#define elf_read_implies_exec(ex, executable_stack) \
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(executable_stack != EXSTACK_DISABLE_X)
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struct task_struct;
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#define ARCH_DLINFO_IA32 \
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do { \
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if (vdso32_enabled) { \
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NEW_AUX_ENT(AT_SYSINFO, VDSO_ENTRY); \
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NEW_AUX_ENT(AT_SYSINFO_EHDR, VDSO_CURRENT_BASE); \
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} \
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} while (0)
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#ifdef CONFIG_X86_32
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#define STACK_RND_MASK (0x7ff)
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#define ARCH_DLINFO ARCH_DLINFO_IA32
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/* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT entries changes */
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#else /* CONFIG_X86_32 */
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/* 1GB for 64bit, 8MB for 32bit */
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#define STACK_RND_MASK (test_thread_flag(TIF_ADDR32) ? 0x7ff : 0x3fffff)
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#define ARCH_DLINFO \
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do { \
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if (vdso64_enabled) \
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NEW_AUX_ENT(AT_SYSINFO_EHDR, \
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(unsigned long __force)current->mm->context.vdso); \
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} while (0)
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/* As a historical oddity, the x32 and x86_64 vDSOs are controlled together. */
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#define ARCH_DLINFO_X32 \
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do { \
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if (vdso64_enabled) \
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NEW_AUX_ENT(AT_SYSINFO_EHDR, \
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(unsigned long __force)current->mm->context.vdso); \
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} while (0)
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#define AT_SYSINFO 32
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#define COMPAT_ARCH_DLINFO \
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if (test_thread_flag(TIF_X32)) \
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ARCH_DLINFO_X32; \
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else \
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ARCH_DLINFO_IA32
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#define COMPAT_ELF_ET_DYN_BASE (TASK_UNMAPPED_BASE + 0x1000000)
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#endif /* !CONFIG_X86_32 */
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#define VDSO_CURRENT_BASE ((unsigned long)current->mm->context.vdso)
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#define VDSO_ENTRY \
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((unsigned long)current->mm->context.vdso + \
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selected_vdso32->sym___kernel_vsyscall)
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struct linux_binprm;
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#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
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extern int arch_setup_additional_pages(struct linux_binprm *bprm,
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int uses_interp);
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extern int x32_setup_additional_pages(struct linux_binprm *bprm,
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int uses_interp);
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extern int syscall32_setup_pages(struct linux_binprm *, int exstack);
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#define compat_arch_setup_additional_pages syscall32_setup_pages
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extern unsigned long arch_randomize_brk(struct mm_struct *mm);
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#define arch_randomize_brk arch_randomize_brk
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/*
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* True on X86_32 or when emulating IA32 on X86_64
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*/
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static inline int mmap_is_ia32(void)
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{
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#ifdef CONFIG_X86_32
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return 1;
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#endif
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#ifdef CONFIG_IA32_EMULATION
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if (test_thread_flag(TIF_ADDR32))
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return 1;
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#endif
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return 0;
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}
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/* Do not change the values. See get_align_mask() */
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enum align_flags {
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ALIGN_VA_32 = BIT(0),
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ALIGN_VA_64 = BIT(1),
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};
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struct va_alignment {
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int flags;
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unsigned long mask;
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} ____cacheline_aligned;
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extern struct va_alignment va_align;
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extern unsigned long align_vdso_addr(unsigned long);
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#endif /* _ASM_X86_ELF_H */
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