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 9 #ifndef CONFIG_64BIT 10 11 /* 12 * Generic 32bit nops from GAS: 13 * 14 * 1: nop 15 * 2: movl %esi,%esi 16 * 3: leal 0x0(%esi),%esi 17 * 4: leal 0x0(%esi,%eiz,1),%esi 18 * 5: leal %ds:0x0(%esi,%eiz,1),%esi 19 * 6: leal 0x0(%esi),%esi 20 * 7: leal 0x0(%esi,%eiz,1),%esi 21 * 8: leal %ds:0x0(%esi,%eiz,1),%esi 22 * 23 * Except 5 and 8, which are DS prefixed 4 and 7 resp, where GAS would emit 2 24 * nop instructions. 25 */ 26 #define BYTES_NOP1 0x90 27 #define BYTES_NOP2 0x89,0xf6 28 #define BYTES_NOP3 0x8d,0x76,0x00 29 #define BYTES_NOP4 0x8d,0x74,0x26,0x00 30 #define BYTES_NOP5 0x3e,BYTES_NOP4 31 #define BYTES_NOP6 0x8d,0xb6,0x00,0x00,0x00,0x00 32 #define BYTES_NOP7 0x8d,0xb4,0x26,0x00,0x00,0x00,0x00 33 #define BYTES_NOP8 0x3e,BYTES_NOP7 34 35 #else 36 37 /* 38 * Generic 64bit nops from GAS: 39 * 40 * 1: nop 41 * 2: osp nop 42 * 3: nopl (%eax) 43 * 4: nopl 0x00(%eax) 44 * 5: nopl 0x00(%eax,%eax,1) 45 * 6: osp nopl 0x00(%eax,%eax,1) 46 * 7: nopl 0x00000000(%eax) 47 * 8: nopl 0x00000000(%eax,%eax,1) 48 */ 49 #define BYTES_NOP1 0x90 50 #define BYTES_NOP2 0x66,BYTES_NOP1 51 #define BYTES_NOP3 0x0f,0x1f,0x00 52 #define BYTES_NOP4 0x0f,0x1f,0x40,0x00 53 #define BYTES_NOP5 0x0f,0x1f,0x44,0x00,0x00 54 #define BYTES_NOP6 0x66,BYTES_NOP5 55 #define BYTES_NOP7 0x0f,0x1f,0x80,0x00,0x00,0x00,0x00 56 #define BYTES_NOP8 0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00 57 58 #endif /* CONFIG_64BIT */ 59 60 #ifdef __ASSEMBLY__ 61 #define _ASM_MK_NOP(x) .byte x 62 #else 63 #define _ASM_MK_NOP(x) ".byte " __stringify(x) "\n" 64 #endif 65 66 #define ASM_NOP1 _ASM_MK_NOP(BYTES_NOP1) 67 #define ASM_NOP2 _ASM_MK_NOP(BYTES_NOP2) 68 #define ASM_NOP3 _ASM_MK_NOP(BYTES_NOP3) 69 #define ASM_NOP4 _ASM_MK_NOP(BYTES_NOP4) 70 #define ASM_NOP5 _ASM_MK_NOP(BYTES_NOP5) 71 #define ASM_NOP6 _ASM_MK_NOP(BYTES_NOP6) 72 #define ASM_NOP7 _ASM_MK_NOP(BYTES_NOP7) 73 #define ASM_NOP8 _ASM_MK_NOP(BYTES_NOP8) 74 75 #define ASM_NOP_MAX 8 76 77 #ifndef __ASSEMBLY__ 78 extern const unsigned char * const x86_nops[]; 79 #endif 80 81 #endif /* _ASM_X86_NOPS_H */ 82