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H. Peter Anvin1965aae2008-10-22 22:26:29 -07001#ifndef _ASM_X86_NOPS_H
2#define _ASM_X86_NOPS_H
Andi Kleenbd616432008-01-30 13:32:38 +01003
H. Peter Anvindc326fc2011-04-18 15:19:51 -07004/*
5 * Define nops for use with alternative() and for tracing.
6 *
7 * *_NOP5_ATOMIC must be a single instruction.
8 */
9
10#define NOP_DS_PREFIX 0x3e
Andi Kleenbd616432008-01-30 13:32:38 +010011
H. Peter Anvin4cd20952008-02-18 23:24:33 -080012/* generic versions from gas
13 1: nop
Mikael Pettersson5d570cb2008-03-11 16:43:31 +010014 the following instructions are NOT nops in 64-bit mode,
15 for 64-bit mode use K8 or P6 nops instead
H. Peter Anvin4cd20952008-02-18 23:24:33 -080016 2: movl %esi,%esi
17 3: leal 0x00(%esi),%esi
18 4: leal 0x00(,%esi,1),%esi
19 6: leal 0x00000000(%esi),%esi
20 7: leal 0x00000000(,%esi,1),%esi
21*/
H. Peter Anvindc326fc2011-04-18 15:19:51 -070022#define GENERIC_NOP1 0x90
23#define GENERIC_NOP2 0x89,0xf6
24#define GENERIC_NOP3 0x8d,0x76,0x00
25#define GENERIC_NOP4 0x8d,0x74,0x26,0x00
26#define GENERIC_NOP5 GENERIC_NOP1,GENERIC_NOP4
27#define GENERIC_NOP6 0x8d,0xb6,0x00,0x00,0x00,0x00
28#define GENERIC_NOP7 0x8d,0xb4,0x26,0x00,0x00,0x00,0x00
29#define GENERIC_NOP8 GENERIC_NOP1,GENERIC_NOP7
30#define GENERIC_NOP5_ATOMIC NOP_DS_PREFIX,GENERIC_NOP4
Andi Kleenbd616432008-01-30 13:32:38 +010031
H. Peter Anvin4cd20952008-02-18 23:24:33 -080032/* Opteron 64bit nops
33 1: nop
34 2: osp nop
35 3: osp osp nop
36 4: osp osp osp nop
37*/
Andi Kleenbd616432008-01-30 13:32:38 +010038#define K8_NOP1 GENERIC_NOP1
H. Peter Anvindc326fc2011-04-18 15:19:51 -070039#define K8_NOP2 0x66,K8_NOP1
40#define K8_NOP3 0x66,K8_NOP2
41#define K8_NOP4 0x66,K8_NOP3
42#define K8_NOP5 K8_NOP3,K8_NOP2
43#define K8_NOP6 K8_NOP3,K8_NOP3
44#define K8_NOP7 K8_NOP4,K8_NOP3
45#define K8_NOP8 K8_NOP4,K8_NOP4
46#define K8_NOP5_ATOMIC 0x66,K8_NOP4
Andi Kleenbd616432008-01-30 13:32:38 +010047
H. Peter Anvin4cd20952008-02-18 23:24:33 -080048/* K7 nops
Lucas De Marchi0d2eb442011-03-17 16:24:16 -030049 uses eax dependencies (arbitrary choice)
H. Peter Anvin4cd20952008-02-18 23:24:33 -080050 1: nop
51 2: movl %eax,%eax
52 3: leal (,%eax,1),%eax
53 4: leal 0x00(,%eax,1),%eax
54 6: leal 0x00000000(%eax),%eax
55 7: leal 0x00000000(,%eax,1),%eax
56*/
57#define K7_NOP1 GENERIC_NOP1
H. Peter Anvindc326fc2011-04-18 15:19:51 -070058#define K7_NOP2 0x8b,0xc0
59#define K7_NOP3 0x8d,0x04,0x20
60#define K7_NOP4 0x8d,0x44,0x20,0x00
61#define K7_NOP5 K7_NOP4,K7_NOP1
62#define K7_NOP6 0x8d,0x80,0,0,0,0
63#define K7_NOP7 0x8D,0x04,0x05,0,0,0,0
64#define K7_NOP8 K7_NOP7,K7_NOP1
65#define K7_NOP5_ATOMIC NOP_DS_PREFIX,K7_NOP4
Andi Kleenbd616432008-01-30 13:32:38 +010066
H. Peter Anvin4cd20952008-02-18 23:24:33 -080067/* P6 nops
68 uses eax dependencies (Intel-recommended choice)
69 1: nop
70 2: osp nop
71 3: nopl (%eax)
72 4: nopl 0x00(%eax)
73 5: nopl 0x00(%eax,%eax,1)
74 6: osp nopl 0x00(%eax,%eax,1)
75 7: nopl 0x00000000(%eax)
76 8: nopl 0x00000000(%eax,%eax,1)
Steven Rostedtfc06b852009-09-10 17:22:44 -040077 Note: All the above are assumed to be a single instruction.
78 There is kernel code that depends on this.
H. Peter Anvin4cd20952008-02-18 23:24:33 -080079*/
Andi Kleenbd616432008-01-30 13:32:38 +010080#define P6_NOP1 GENERIC_NOP1
H. Peter Anvindc326fc2011-04-18 15:19:51 -070081#define P6_NOP2 0x66,0x90
82#define P6_NOP3 0x0f,0x1f,0x00
83#define P6_NOP4 0x0f,0x1f,0x40,0
84#define P6_NOP5 0x0f,0x1f,0x44,0x00,0
85#define P6_NOP6 0x66,0x0f,0x1f,0x44,0x00,0
86#define P6_NOP7 0x0f,0x1f,0x80,0,0,0,0
87#define P6_NOP8 0x0f,0x1f,0x84,0x00,0,0,0,0
88#define P6_NOP5_ATOMIC P6_NOP5
89
90#define _ASM_MK_NOP(x) ".byte " __stringify(x) "\n"
Andi Kleenbd616432008-01-30 13:32:38 +010091
Suresh Siddha871de932008-04-07 11:56:34 -070092#if defined(CONFIG_MK7)
H. Peter Anvindc326fc2011-04-18 15:19:51 -070093#define ASM_NOP1 _ASM_MK_NOP(K7_NOP1)
94#define ASM_NOP2 _ASM_MK_NOP(K7_NOP2)
95#define ASM_NOP3 _ASM_MK_NOP(K7_NOP3)
96#define ASM_NOP4 _ASM_MK_NOP(K7_NOP4)
97#define ASM_NOP5 _ASM_MK_NOP(K7_NOP5)
98#define ASM_NOP6 _ASM_MK_NOP(K7_NOP6)
99#define ASM_NOP7 _ASM_MK_NOP(K7_NOP7)
100#define ASM_NOP8 _ASM_MK_NOP(K7_NOP8)
101#define ASM_NOP5_ATOMIC _ASM_MK_NOP(K7_NOP5_ATOMIC)
H. Peter Anvin7343b3b2008-02-14 14:52:05 -0800102#elif defined(CONFIG_X86_P6_NOP)
H. Peter Anvindc326fc2011-04-18 15:19:51 -0700103#define ASM_NOP1 _ASM_MK_NOP(P6_NOP1)
104#define ASM_NOP2 _ASM_MK_NOP(P6_NOP2)
105#define ASM_NOP3 _ASM_MK_NOP(P6_NOP3)
106#define ASM_NOP4 _ASM_MK_NOP(P6_NOP4)
107#define ASM_NOP5 _ASM_MK_NOP(P6_NOP5)
108#define ASM_NOP6 _ASM_MK_NOP(P6_NOP6)
109#define ASM_NOP7 _ASM_MK_NOP(P6_NOP7)
110#define ASM_NOP8 _ASM_MK_NOP(P6_NOP8)
111#define ASM_NOP5_ATOMIC _ASM_MK_NOP(P6_NOP5_ATOMIC)
Suresh Siddha871de932008-04-07 11:56:34 -0700112#elif defined(CONFIG_X86_64)
H. Peter Anvindc326fc2011-04-18 15:19:51 -0700113#define ASM_NOP1 _ASM_MK_NOP(K8_NOP1)
114#define ASM_NOP2 _ASM_MK_NOP(K8_NOP2)
115#define ASM_NOP3 _ASM_MK_NOP(K8_NOP3)
116#define ASM_NOP4 _ASM_MK_NOP(K8_NOP4)
117#define ASM_NOP5 _ASM_MK_NOP(K8_NOP5)
118#define ASM_NOP6 _ASM_MK_NOP(K8_NOP6)
119#define ASM_NOP7 _ASM_MK_NOP(K8_NOP7)
120#define ASM_NOP8 _ASM_MK_NOP(K8_NOP8)
121#define ASM_NOP5_ATOMIC _ASM_MK_NOP(K8_NOP5_ATOMIC)
Andi Kleenbd616432008-01-30 13:32:38 +0100122#else
H. Peter Anvindc326fc2011-04-18 15:19:51 -0700123#define ASM_NOP1 _ASM_MK_NOP(GENERIC_NOP1)
124#define ASM_NOP2 _ASM_MK_NOP(GENERIC_NOP2)
125#define ASM_NOP3 _ASM_MK_NOP(GENERIC_NOP3)
126#define ASM_NOP4 _ASM_MK_NOP(GENERIC_NOP4)
127#define ASM_NOP5 _ASM_MK_NOP(GENERIC_NOP5)
128#define ASM_NOP6 _ASM_MK_NOP(GENERIC_NOP6)
129#define ASM_NOP7 _ASM_MK_NOP(GENERIC_NOP7)
130#define ASM_NOP8 _ASM_MK_NOP(GENERIC_NOP8)
131#define ASM_NOP5_ATOMIC _ASM_MK_NOP(GENERIC_NOP5_ATOMIC)
Andi Kleenbd616432008-01-30 13:32:38 +0100132#endif
133
134#define ASM_NOP_MAX 8
H. Peter Anvindc326fc2011-04-18 15:19:51 -0700135#define NOP_ATOMIC5 (ASM_NOP_MAX+1) /* Entry for the 5-byte atomic NOP */
136
137#ifndef __ASSEMBLY__
138extern const unsigned char * const *ideal_nops;
139extern void arch_init_ideal_nops(void);
140#endif
Andi Kleenbd616432008-01-30 13:32:38 +0100141
H. Peter Anvin1965aae2008-10-22 22:26:29 -0700142#endif /* _ASM_X86_NOPS_H */