diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2021-03-12 12:32:55 +0100 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-03-15 16:37:37 +0100 |
| commit | 301cddc21a157a3072d789a3097857202e550a24 (patch) | |
| tree | 77fec47c4e9ab4fa5acd079a71bb3e60b1f805c1 /tools/arch | |
| parent | a89dfde3dc3c2dbf56910af75e2d8b11ec5308f6 (diff) | |
objtool/x86: Use asm/nops.h
Since the kernel will rely on a single canonical set of NOPs, make sure
objtool uses the exact same ones.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210312115749.136357911@infradead.org
Diffstat (limited to 'tools/arch')
| -rw-r--r-- | tools/arch/x86/include/asm/nops.h | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/tools/arch/x86/include/asm/nops.h b/tools/arch/x86/include/asm/nops.h new file mode 100644 index 000000000000..c1e5e818ba16 --- /dev/null +++ b/tools/arch/x86/include/asm/nops.h @@ -0,0 +1,81 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_NOPS_H +#define _ASM_X86_NOPS_H + +/* + * Define nops for use with alternative() and for tracing. + */ + +#ifndef CONFIG_64BIT + +/* + * Generic 32bit nops from GAS: + * + * 1: nop + * 2: movl %esi,%esi + * 3: leal 0x0(%esi),%esi + * 4: leal 0x0(%esi,%eiz,1),%esi + * 5: leal %ds:0x0(%esi,%eiz,1),%esi + * 6: leal 0x0(%esi),%esi + * 7: leal 0x0(%esi,%eiz,1),%esi + * 8: leal %ds:0x0(%esi,%eiz,1),%esi + * + * Except 5 and 8, which are DS prefixed 4 and 7 resp, where GAS would emit 2 + * nop instructions. + */ +#define BYTES_NOP1 0x90 +#define BYTES_NOP2 0x89,0xf6 +#define BYTES_NOP3 0x8d,0x76,0x00 +#define BYTES_NOP4 0x8d,0x74,0x26,0x00 +#define BYTES_NOP5 0x3e,BYTES_NOP4 +#define BYTES_NOP6 0x8d,0xb6,0x00,0x00,0x00,0x00 +#define BYTES_NOP7 0x8d,0xb4,0x26,0x00,0x00,0x00,0x00 +#define BYTES_NOP8 0x3e,BYTES_NOP7 + +#else + +/* + * Generic 64bit nops from GAS: + * + * 1: nop + * 2: osp nop + * 3: nopl (%eax) + * 4: nopl 0x00(%eax) + * 5: nopl 0x00(%eax,%eax,1) + * 6: osp nopl 0x00(%eax,%eax,1) + * 7: nopl 0x00000000(%eax) + * 8: nopl 0x00000000(%eax,%eax,1) + */ +#define BYTES_NOP1 0x90 +#define BYTES_NOP2 0x66,BYTES_NOP1 +#define BYTES_NOP3 0x0f,0x1f,0x00 +#define BYTES_NOP4 0x0f,0x1f,0x40,0x00 +#define BYTES_NOP5 0x0f,0x1f,0x44,0x00,0x00 +#define BYTES_NOP6 0x66,BYTES_NOP5 +#define BYTES_NOP7 0x0f,0x1f,0x80,0x00,0x00,0x00,0x00 +#define BYTES_NOP8 0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00 + +#endif /* CONFIG_64BIT */ + +#ifdef __ASSEMBLY__ +#define _ASM_MK_NOP(x) .byte x +#else +#define _ASM_MK_NOP(x) ".byte " __stringify(x) "\n" +#endif + +#define ASM_NOP1 _ASM_MK_NOP(BYTES_NOP1) +#define ASM_NOP2 _ASM_MK_NOP(BYTES_NOP2) +#define ASM_NOP3 _ASM_MK_NOP(BYTES_NOP3) +#define ASM_NOP4 _ASM_MK_NOP(BYTES_NOP4) +#define ASM_NOP5 _ASM_MK_NOP(BYTES_NOP5) +#define ASM_NOP6 _ASM_MK_NOP(BYTES_NOP6) +#define ASM_NOP7 _ASM_MK_NOP(BYTES_NOP7) +#define ASM_NOP8 _ASM_MK_NOP(BYTES_NOP8) + +#define ASM_NOP_MAX 8 + +#ifndef __ASSEMBLY__ +extern const unsigned char * const x86_nops[]; +#endif + +#endif /* _ASM_X86_NOPS_H */ |