LXR linux/arch/x86/include/asm/nops.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _ASM_X86_NOPS_H
   3#define _ASM_X86_NOPS_H
   4
   5/*
   6 * Define nops for use with alternative() and for tracing.
   7 *
   8 * *_NOP5_ATOMIC must be a single instruction.
   9 */
  10
  11#define NOP_DS_PREFIX 0x3e
  12
  13/* generic versions from gas
  14   1: nop
  15   the following instructions are NOT nops in 64-bit mode,
  16   for 64-bit mode use K8 or P6 nops instead
  17   2: movl %esi,%esi
  18   3: leal 0x00(%esi),%esi
  19   4: leal 0x00(,%esi,1),%esi
  20   6: leal 0x00000000(%esi),%esi
  21   7: leal 0x00000000(,%esi,1),%esi
  22*/
  23#define GENERIC_NOP1 0x90
  24#define GENERIC_NOP2 0x89,0xf6
  25#define GENERIC_NOP3 0x8d,0x76,0x00
  26#define GENERIC_NOP4 0x8d,0x74,0x26,0x00
  27#define GENERIC_NOP5 GENERIC_NOP1,GENERIC_NOP4
  28#define GENERIC_NOP6 0x8d,0xb6,0x00,0x00,0x00,0x00
  29#define GENERIC_NOP7 0x8d,0xb4,0x26,0x00,0x00,0x00,0x00
  30#define GENERIC_NOP8 GENERIC_NOP1,GENERIC_NOP7
  31#define GENERIC_NOP5_ATOMIC NOP_DS_PREFIX,GENERIC_NOP4
  32
  33/* Opteron 64bit nops
  34   1: nop
  35   2: osp nop
  36   3: osp osp nop
  37   4: osp osp osp nop
  38*/
  39#define K8_NOP1 GENERIC_NOP1
  40#define K8_NOP2 0x66,K8_NOP1
  41#define K8_NOP3 0x66,K8_NOP2
  42#define K8_NOP4 0x66,K8_NOP3
  43#define K8_NOP5 K8_NOP3,K8_NOP2
  44#define K8_NOP6 K8_NOP3,K8_NOP3
  45#define K8_NOP7 K8_NOP4,K8_NOP3
  46#define K8_NOP8 K8_NOP4,K8_NOP4
  47#define K8_NOP5_ATOMIC 0x66,K8_NOP4
  48
  49/* K7 nops
  50   uses eax dependencies (arbitrary choice)
  51   1: nop
  52   2: movl %eax,%eax
  53   3: leal (,%eax,1),%eax
  54   4: leal 0x00(,%eax,1),%eax
  55   6: leal 0x00000000(%eax),%eax
  56   7: leal 0x00000000(,%eax,1),%eax
  57*/
  58#define K7_NOP1 GENERIC_NOP1
  59#define K7_NOP2 0x8b,0xc0
  60#define K7_NOP3 0x8d,0x04,0x20
  61#define K7_NOP4 0x8d,0x44,0x20,0x00
  62#define K7_NOP5 K7_NOP4,K7_NOP1
  63#define K7_NOP6 0x8d,0x80,0,0,0,0
  64#define K7_NOP7 0x8D,0x04,0x05,0,0,0,0
  65#define K7_NOP8 K7_NOP7,K7_NOP1
  66#define K7_NOP5_ATOMIC NOP_DS_PREFIX,K7_NOP4
  67
  68/* P6 nops
  69   uses eax dependencies (Intel-recommended choice)
  70   1: nop
  71   2: osp nop
  72   3: nopl (%eax)
  73   4: nopl 0x00(%eax)
  74   5: nopl 0x00(%eax,%eax,1)
  75   6: osp nopl 0x00(%eax,%eax,1)
  76   7: nopl 0x00000000(%eax)
  77   8: nopl 0x00000000(%eax,%eax,1)
  78   Note: All the above are assumed to be a single instruction.
  79        There is kernel code that depends on this.
  80*/
  81#define P6_NOP1 GENERIC_NOP1
  82#define P6_NOP2 0x66,0x90
  83#define P6_NOP3 0x0f,0x1f,0x00
  84#define P6_NOP4 0x0f,0x1f,0x40,0
  85#define P6_NOP5 0x0f,0x1f,0x44,0x00,0
  86#define P6_NOP6 0x66,0x0f,0x1f,0x44,0x00,0
  87#define P6_NOP7 0x0f,0x1f,0x80,0,0,0,0
  88#define P6_NOP8 0x0f,0x1f,0x84,0x00,0,0,0,0
  89#define P6_NOP5_ATOMIC P6_NOP5
  90
  91#ifdef __ASSEMBLY__
  92#define _ASM_MK_NOP(x) .byte x
  93#else
  94#define _ASM_MK_NOP(x) ".byte " __stringify(x) "\n"
  95#endif
  96
  97#if defined(CONFIG_MK7)
  98#define ASM_NOP1 _ASM_MK_NOP(K7_NOP1)
  99#define ASM_NOP2 _ASM_MK_NOP(K7_NOP2)
 100#define ASM_NOP3 _ASM_MK_NOP(K7_NOP3)
 101#define ASM_NOP4 _ASM_MK_NOP(K7_NOP4)
 102#define ASM_NOP5 _ASM_MK_NOP(K7_NOP5)
 103#define ASM_NOP6 _ASM_MK_NOP(K7_NOP6)
 104#define ASM_NOP7 _ASM_MK_NOP(K7_NOP7)
 105#define ASM_NOP8 _ASM_MK_NOP(K7_NOP8)
 106#define ASM_NOP5_ATOMIC _ASM_MK_NOP(K7_NOP5_ATOMIC)
 107#elif defined(CONFIG_X86_P6_NOP)
 108#define ASM_NOP1 _ASM_MK_NOP(P6_NOP1)
 109#define ASM_NOP2 _ASM_MK_NOP(P6_NOP2)
 110#define ASM_NOP3 _ASM_MK_NOP(P6_NOP3)
 111#define ASM_NOP4 _ASM_MK_NOP(P6_NOP4)
 112#define ASM_NOP5 _ASM_MK_NOP(P6_NOP5)
 113#define ASM_NOP6 _ASM_MK_NOP(P6_NOP6)
 114#define ASM_NOP7 _ASM_MK_NOP(P6_NOP7)
 115#define ASM_NOP8 _ASM_MK_NOP(P6_NOP8)
 116#define ASM_NOP5_ATOMIC _ASM_MK_NOP(P6_NOP5_ATOMIC)
 117#elif defined(CONFIG_X86_64)
 118#define ASM_NOP1 _ASM_MK_NOP(K8_NOP1)
 119#define ASM_NOP2 _ASM_MK_NOP(K8_NOP2)
 120#define ASM_NOP3 _ASM_MK_NOP(K8_NOP3)
 121#define ASM_NOP4 _ASM_MK_NOP(K8_NOP4)
 122#define ASM_NOP5 _ASM_MK_NOP(K8_NOP5)
 123#define ASM_NOP6 _ASM_MK_NOP(K8_NOP6)
 124#define ASM_NOP7 _ASM_MK_NOP(K8_NOP7)
 125#define ASM_NOP8 _ASM_MK_NOP(K8_NOP8)
 126#define ASM_NOP5_ATOMIC _ASM_MK_NOP(K8_NOP5_ATOMIC)
 127#else
 128#define ASM_NOP1 _ASM_MK_NOP(GENERIC_NOP1)
 129#define ASM_NOP2 _ASM_MK_NOP(GENERIC_NOP2)
 130#define ASM_NOP3 _ASM_MK_NOP(GENERIC_NOP3)
 131#define ASM_NOP4 _ASM_MK_NOP(GENERIC_NOP4)
 132#define ASM_NOP5 _ASM_MK_NOP(GENERIC_NOP5)
 133#define ASM_NOP6 _ASM_MK_NOP(GENERIC_NOP6)
 134#define ASM_NOP7 _ASM_MK_NOP(GENERIC_NOP7)
 135#define ASM_NOP8 _ASM_MK_NOP(GENERIC_NOP8)
 136#define ASM_NOP5_ATOMIC _ASM_MK_NOP(GENERIC_NOP5_ATOMIC)
 137#endif
 138
 139#define ASM_NOP_MAX 8
 140#define NOP_ATOMIC5 (ASM_NOP_MAX+1)     /* Entry for the 5-byte atomic NOP */
 141
 142#ifndef __ASSEMBLY__
 143extern const unsigned char * const *ideal_nops;
 144extern void arch_init_ideal_nops(void);
 145#endif
 146
 147#endif /* _ASM_X86_NOPS_H */
 148