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__
 143 extern const unsigned char * const *ideal_nops;
 144 extern void arch_init_ideal_nops(void);
 145 #endif
 146
 147 #endif /* _ASM_X86_NOPS_H */