Commit 301cddc2 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Borislav Petkov
Browse files

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: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210312115749.136357911@infradead.org
parent a89dfde3

tools/arch/x86/include/asm/nops.h

0 → 100644
+81 −0
Original line number Diff line number Diff line 
/* 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 */

tools/objtool/arch/x86/decode.c

+8 −5
Original line number Diff line number Diff line
@@ -11,6 +11,9 @@ 
#include "../../../arch/x86/lib/inat.c"

#include "../../../arch/x86/lib/insn.c"



#define CONFIG_64BIT 1

#include <asm/nops.h>



#include <asm/orc_types.h>

#include <objtool/check.h>

#include <objtool/elf.h>
@@ -596,11 +599,11 @@ void arch_initial_func_cfi_state(struct cfi_init_state *state) 
const char *arch_nop_insn(int len)

{

	static const char nops[5][5] = {

		/* 1 */ { 0x90 },

		/* 2 */ { 0x66, 0x90 },

		/* 3 */ { 0x0f, 0x1f, 0x00 },

		/* 4 */ { 0x0f, 0x1f, 0x40, 0x00 },

		/* 5 */ { 0x0f, 0x1f, 0x44, 0x00, 0x00 },

		{ BYTES_NOP1 },

		{ BYTES_NOP2 },

		{ BYTES_NOP3 },

		{ BYTES_NOP4 },

		{ BYTES_NOP5 },

	};



	if (len < 1 || len > 5) {

tools/objtool/sync-check.sh

+1 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ FILES="include/linux/objtool.h" 


if [ "$SRCARCH" = "x86" ]; then

FILES="$FILES

arch/x86/include/asm/nops.h

arch/x86/include/asm/inat_types.h

arch/x86/include/asm/orc_types.h

arch/x86/include/asm/emulate_prefix.h