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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/tools/arch/x86/include/asm/nops.h
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/* SPDX-License-Identifier: GPL-2.0 */

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#ifndef _ASM_X86_NOPS_H

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#define _ASM_X86_NOPS_H

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#include <asm/asm.h>

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/*

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 * Define nops for use with alternative() and for tracing.

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 */

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#ifndef CONFIG_64BIT

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/*

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 * Generic 32bit nops from GAS:

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 *

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 * 1: nop

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 * 2: movl %esi,%esi

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 * 3: leal 0x0(%esi),%esi

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 * 4: leal 0x0(%esi,%eiz,1),%esi

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 * 5: leal %ds:0x0(%esi,%eiz,1),%esi

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 * 6: leal 0x0(%esi),%esi

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 * 7: leal 0x0(%esi,%eiz,1),%esi

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 * 8: leal %ds:0x0(%esi,%eiz,1),%esi

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 *

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 * Except 5 and 8, which are DS prefixed 4 and 7 resp, where GAS would emit 2

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 * nop instructions.

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 */

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#define BYTES_NOP1	0x90

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#define BYTES_NOP2	0x89,0xf6

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#define BYTES_NOP3	0x8d,0x76,0x00

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#define BYTES_NOP4	0x8d,0x74,0x26,0x00

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#define BYTES_NOP5	0x3e,BYTES_NOP4

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#define BYTES_NOP6	0x8d,0xb6,0x00,0x00,0x00,0x00

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#define BYTES_NOP7	0x8d,0xb4,0x26,0x00,0x00,0x00,0x00

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#define BYTES_NOP8	0x3e,BYTES_NOP7

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#define ASM_NOP_MAX 8

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#else

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/*

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 * Generic 64bit nops from GAS:

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 *

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 * 1: nop

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 * 2: osp nop

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 * 3: nopl (%eax)

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 * 4: nopl 0x00(%eax)

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 * 5: nopl 0x00(%eax,%eax,1)

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 * 6: osp nopl 0x00(%eax,%eax,1)

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 * 7: nopl 0x00000000(%eax)

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 * 8: nopl 0x00000000(%eax,%eax,1)

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 * 9: cs nopl 0x00000000(%eax,%eax,1)

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 * 10: osp cs nopl 0x00000000(%eax,%eax,1)

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 * 11: osp osp cs nopl 0x00000000(%eax,%eax,1)

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 */

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#define BYTES_NOP1	0x90

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#define BYTES_NOP2	0x66,BYTES_NOP1

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#define BYTES_NOP3	0x0f,0x1f,0x00

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#define BYTES_NOP4	0x0f,0x1f,0x40,0x00

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#define BYTES_NOP5	0x0f,0x1f,0x44,0x00,0x00

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#define BYTES_NOP6	0x66,BYTES_NOP5

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#define BYTES_NOP7	0x0f,0x1f,0x80,0x00,0x00,0x00,0x00

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#define BYTES_NOP8	0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00

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#define BYTES_NOP9	0x2e,BYTES_NOP8

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#define BYTES_NOP10	0x66,BYTES_NOP9

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#define BYTES_NOP11	0x66,BYTES_NOP10

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#define ASM_NOP9  _ASM_BYTES(BYTES_NOP9)

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#define ASM_NOP10 _ASM_BYTES(BYTES_NOP10)

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#define ASM_NOP11 _ASM_BYTES(BYTES_NOP11)

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#define ASM_NOP_MAX 11

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#endif /* CONFIG_64BIT */

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#define ASM_NOP1 _ASM_BYTES(BYTES_NOP1)

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#define ASM_NOP2 _ASM_BYTES(BYTES_NOP2)

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#define ASM_NOP3 _ASM_BYTES(BYTES_NOP3)

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#define ASM_NOP4 _ASM_BYTES(BYTES_NOP4)

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#define ASM_NOP5 _ASM_BYTES(BYTES_NOP5)

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#define ASM_NOP6 _ASM_BYTES(BYTES_NOP6)

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#define ASM_NOP7 _ASM_BYTES(BYTES_NOP7)

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#define ASM_NOP8 _ASM_BYTES(BYTES_NOP8)

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#ifndef __ASSEMBLER__

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extern const unsigned char * const x86_nops[];

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#endif

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#endif /* _ASM_X86_NOPS_H */

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