mirror of
https://github.com/torvalds/linux.git
synced 2024-11-23 20:51:44 +00:00
5d570cbbf2
<asm-x86/nops.h> describes certain multibyte instructions as "generic" nops when in fact they aren't nops at all in 64-bit mode (missing REX.W causing truncation of a register). Update the comment to state that K8 or P6 style nops should be used in 64-bit mode. This matches what the alternatives code does. Signed-off-by: Mikael Pettersson <mikpe@it.uu.se> Signed-off-by: Ingo Molnar <mingo@elte.hu>
119 lines
3.2 KiB
C
119 lines
3.2 KiB
C
#ifndef _ASM_NOPS_H
|
|
#define _ASM_NOPS_H 1
|
|
|
|
/* Define nops for use with alternative() */
|
|
|
|
/* generic versions from gas
|
|
1: nop
|
|
the following instructions are NOT nops in 64-bit mode,
|
|
for 64-bit mode use K8 or P6 nops instead
|
|
2: movl %esi,%esi
|
|
3: leal 0x00(%esi),%esi
|
|
4: leal 0x00(,%esi,1),%esi
|
|
6: leal 0x00000000(%esi),%esi
|
|
7: leal 0x00000000(,%esi,1),%esi
|
|
*/
|
|
#define GENERIC_NOP1 ".byte 0x90\n"
|
|
#define GENERIC_NOP2 ".byte 0x89,0xf6\n"
|
|
#define GENERIC_NOP3 ".byte 0x8d,0x76,0x00\n"
|
|
#define GENERIC_NOP4 ".byte 0x8d,0x74,0x26,0x00\n"
|
|
#define GENERIC_NOP5 GENERIC_NOP1 GENERIC_NOP4
|
|
#define GENERIC_NOP6 ".byte 0x8d,0xb6,0x00,0x00,0x00,0x00\n"
|
|
#define GENERIC_NOP7 ".byte 0x8d,0xb4,0x26,0x00,0x00,0x00,0x00\n"
|
|
#define GENERIC_NOP8 GENERIC_NOP1 GENERIC_NOP7
|
|
|
|
/* Opteron 64bit nops
|
|
1: nop
|
|
2: osp nop
|
|
3: osp osp nop
|
|
4: osp osp osp nop
|
|
*/
|
|
#define K8_NOP1 GENERIC_NOP1
|
|
#define K8_NOP2 ".byte 0x66,0x90\n"
|
|
#define K8_NOP3 ".byte 0x66,0x66,0x90\n"
|
|
#define K8_NOP4 ".byte 0x66,0x66,0x66,0x90\n"
|
|
#define K8_NOP5 K8_NOP3 K8_NOP2
|
|
#define K8_NOP6 K8_NOP3 K8_NOP3
|
|
#define K8_NOP7 K8_NOP4 K8_NOP3
|
|
#define K8_NOP8 K8_NOP4 K8_NOP4
|
|
|
|
/* K7 nops
|
|
uses eax dependencies (arbitary choice)
|
|
1: nop
|
|
2: movl %eax,%eax
|
|
3: leal (,%eax,1),%eax
|
|
4: leal 0x00(,%eax,1),%eax
|
|
6: leal 0x00000000(%eax),%eax
|
|
7: leal 0x00000000(,%eax,1),%eax
|
|
*/
|
|
#define K7_NOP1 GENERIC_NOP1
|
|
#define K7_NOP2 ".byte 0x8b,0xc0\n"
|
|
#define K7_NOP3 ".byte 0x8d,0x04,0x20\n"
|
|
#define K7_NOP4 ".byte 0x8d,0x44,0x20,0x00\n"
|
|
#define K7_NOP5 K7_NOP4 ASM_NOP1
|
|
#define K7_NOP6 ".byte 0x8d,0x80,0,0,0,0\n"
|
|
#define K7_NOP7 ".byte 0x8D,0x04,0x05,0,0,0,0\n"
|
|
#define K7_NOP8 K7_NOP7 ASM_NOP1
|
|
|
|
/* P6 nops
|
|
uses eax dependencies (Intel-recommended choice)
|
|
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 P6_NOP1 GENERIC_NOP1
|
|
#define P6_NOP2 ".byte 0x66,0x90\n"
|
|
#define P6_NOP3 ".byte 0x0f,0x1f,0x00\n"
|
|
#define P6_NOP4 ".byte 0x0f,0x1f,0x40,0\n"
|
|
#define P6_NOP5 ".byte 0x0f,0x1f,0x44,0x00,0\n"
|
|
#define P6_NOP6 ".byte 0x66,0x0f,0x1f,0x44,0x00,0\n"
|
|
#define P6_NOP7 ".byte 0x0f,0x1f,0x80,0,0,0,0\n"
|
|
#define P6_NOP8 ".byte 0x0f,0x1f,0x84,0x00,0,0,0,0\n"
|
|
|
|
#if defined(CONFIG_MK7)
|
|
#define ASM_NOP1 K7_NOP1
|
|
#define ASM_NOP2 K7_NOP2
|
|
#define ASM_NOP3 K7_NOP3
|
|
#define ASM_NOP4 K7_NOP4
|
|
#define ASM_NOP5 K7_NOP5
|
|
#define ASM_NOP6 K7_NOP6
|
|
#define ASM_NOP7 K7_NOP7
|
|
#define ASM_NOP8 K7_NOP8
|
|
#elif defined(CONFIG_X86_P6_NOP)
|
|
#define ASM_NOP1 P6_NOP1
|
|
#define ASM_NOP2 P6_NOP2
|
|
#define ASM_NOP3 P6_NOP3
|
|
#define ASM_NOP4 P6_NOP4
|
|
#define ASM_NOP5 P6_NOP5
|
|
#define ASM_NOP6 P6_NOP6
|
|
#define ASM_NOP7 P6_NOP7
|
|
#define ASM_NOP8 P6_NOP8
|
|
#elif defined(CONFIG_X86_64)
|
|
#define ASM_NOP1 K8_NOP1
|
|
#define ASM_NOP2 K8_NOP2
|
|
#define ASM_NOP3 K8_NOP3
|
|
#define ASM_NOP4 K8_NOP4
|
|
#define ASM_NOP5 K8_NOP5
|
|
#define ASM_NOP6 K8_NOP6
|
|
#define ASM_NOP7 K8_NOP7
|
|
#define ASM_NOP8 K8_NOP8
|
|
#else
|
|
#define ASM_NOP1 GENERIC_NOP1
|
|
#define ASM_NOP2 GENERIC_NOP2
|
|
#define ASM_NOP3 GENERIC_NOP3
|
|
#define ASM_NOP4 GENERIC_NOP4
|
|
#define ASM_NOP5 GENERIC_NOP5
|
|
#define ASM_NOP6 GENERIC_NOP6
|
|
#define ASM_NOP7 GENERIC_NOP7
|
|
#define ASM_NOP8 GENERIC_NOP8
|
|
#endif
|
|
|
|
#define ASM_NOP_MAX 8
|
|
|
|
#endif
|