1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 #ifndef _ASM_X86_INSN_H 3 #define _ASM_X86_INSN_H 4 /* 5 * x86 instruction analysis 6 * 7 * Copyright (C) IBM Corporation, 2009 8 */ 9 10 /* insn_attr_t is defined in inat.h */ 11 #include <asm/inat.h> 12 13 struct insn_field { 14 union { 15 insn_value_t value; 16 insn_byte_t bytes[4]; 17 }; 18 /* !0 if we've run insn_get_xxx() for this field */ 19 unsigned char got; 20 unsigned char nbytes; 21 }; 22 23 struct insn { 24 struct insn_field prefixes; /* 25 * Prefixes 26 * prefixes.bytes[3]: last prefix 27 */ 28 struct insn_field rex_prefix; /* REX prefix */ 29 struct insn_field vex_prefix; /* VEX prefix */ 30 struct insn_field opcode; /* 31 * opcode.bytes[0]: opcode1 32 * opcode.bytes[1]: opcode2 33 * opcode.bytes[2]: opcode3 34 */ 35 struct insn_field modrm; 36 struct insn_field sib; 37 struct insn_field displacement; 38 union { 39 struct insn_field immediate; 40 struct insn_field moffset1; /* for 64bit MOV */ 41 struct insn_field immediate1; /* for 64bit imm or off16/32 */ 42 }; 43 union { 44 struct insn_field moffset2; /* for 64bit MOV */ 45 struct insn_field immediate2; /* for 64bit imm or seg16 */ 46 }; 47 48 insn_attr_t attr; 49 unsigned char opnd_bytes; 50 unsigned char addr_bytes; 51 unsigned char length; 52 unsigned char x86_64; 53 54 const insn_byte_t *kaddr; /* kernel address of insn to analyze */ 55 const insn_byte_t *end_kaddr; /* kernel address of last insn in buffer */ 56 const insn_byte_t *next_byte; 57 }; 58 59 #define MAX_INSN_SIZE 15 60 61 #define X86_MODRM_MOD(modrm) (((modrm) & 0xc0) >> 6) 62 #define X86_MODRM_REG(modrm) (((modrm) & 0x38) >> 3) 63 #define X86_MODRM_RM(modrm) ((modrm) & 0x07) 64 65 #define X86_SIB_SCALE(sib) (((sib) & 0xc0) >> 6) 66 #define X86_SIB_INDEX(sib) (((sib) & 0x38) >> 3) 67 #define X86_SIB_BASE(sib) ((sib) & 0x07) 68 69 #define X86_REX_W(rex) ((rex) & 8) 70 #define X86_REX_R(rex) ((rex) & 4) 71 #define X86_REX_X(rex) ((rex) & 2) 72 #define X86_REX_B(rex) ((rex) & 1) 73 74 /* VEX bit flags */ 75 #define X86_VEX_W(vex) ((vex) & 0x80) /* VEX3 Byte2 */ 76 #define X86_VEX_R(vex) ((vex) & 0x80) /* VEX2/3 Byte1 */ 77 #define X86_VEX_X(vex) ((vex) & 0x40) /* VEX3 Byte1 */ 78 #define X86_VEX_B(vex) ((vex) & 0x20) /* VEX3 Byte1 */ 79 #define X86_VEX_L(vex) ((vex) & 0x04) /* VEX3 Byte2, VEX2 Byte1 */ 80 /* VEX bit fields */ 81 #define X86_EVEX_M(vex) ((vex) & 0x03) /* EVEX Byte1 */ 82 #define X86_VEX3_M(vex) ((vex) & 0x1f) /* VEX3 Byte1 */ 83 #define X86_VEX2_M 1 /* VEX2.M always 1 */ 84 #define X86_VEX_V(vex) (((vex) & 0x78) >> 3) /* VEX3 Byte2, VEX2 Byte1 */ 85 #define X86_VEX_P(vex) ((vex) & 0x03) /* VEX3 Byte2, VEX2 Byte1 */ 86 #define X86_VEX_M_MAX 0x1f /* VEX3.M Maximum value */ 87 88 extern void insn_init(struct insn *insn, const void *kaddr, int buf_len, int x86_64); 89 extern void insn_get_prefixes(struct insn *insn); 90 extern void insn_get_opcode(struct insn *insn); 91 extern void insn_get_modrm(struct insn *insn); 92 extern void insn_get_sib(struct insn *insn); 93 extern void insn_get_displacement(struct insn *insn); 94 extern void insn_get_immediate(struct insn *insn); 95 extern void insn_get_length(struct insn *insn); 96 97 /* Attribute will be determined after getting ModRM (for opcode groups) */ 98 static inline void insn_get_attribute(struct insn *insn) 99 { 100 insn_get_modrm(insn); 101 } 102 103 /* Instruction uses RIP-relative addressing */ 104 extern int insn_rip_relative(struct insn *insn); 105 106 /* Init insn for kernel text */ 107 static inline void kernel_insn_init(struct insn *insn, 108 const void *kaddr, int buf_len) 109 { 110 #ifdef CONFIG_X86_64 111 insn_init(insn, kaddr, buf_len, 1); 112 #else /* CONFIG_X86_32 */ 113 insn_init(insn, kaddr, buf_len, 0); 114 #endif 115 } 116 117 static inline int insn_is_avx(struct insn *insn) 118 { 119 if (!insn->prefixes.got) 120 insn_get_prefixes(insn); 121 return (insn->vex_prefix.value != 0); 122 } 123 124 static inline int insn_is_evex(struct insn *insn) 125 { 126 if (!insn->prefixes.got) 127 insn_get_prefixes(insn); 128 return (insn->vex_prefix.nbytes == 4); 129 } 130 131 /* Ensure this instruction is decoded completely */ 132 static inline int insn_complete(struct insn *insn) 133 { 134 return insn->opcode.got && insn->modrm.got && insn->sib.got && 135 insn->displacement.got && insn->immediate.got; 136 } 137 138 static inline insn_byte_t insn_vex_m_bits(struct insn *insn) 139 { 140 if (insn->vex_prefix.nbytes == 2) /* 2 bytes VEX */ 141 return X86_VEX2_M; 142 else if (insn->vex_prefix.nbytes == 3) /* 3 bytes VEX */ 143 return X86_VEX3_M(insn->vex_prefix.bytes[1]); 144 else /* EVEX */ 145 return X86_EVEX_M(insn->vex_prefix.bytes[1]); 146 } 147 148 static inline insn_byte_t insn_vex_p_bits(struct insn *insn) 149 { 150 if (insn->vex_prefix.nbytes == 2) /* 2 bytes VEX */ 151 return X86_VEX_P(insn->vex_prefix.bytes[1]); 152 else 153 return X86_VEX_P(insn->vex_prefix.bytes[2]); 154 } 155 156 /* Get the last prefix id from last prefix or VEX prefix */ 157 static inline int insn_last_prefix_id(struct insn *insn) 158 { 159 if (insn_is_avx(insn)) 160 return insn_vex_p_bits(insn); /* VEX_p is a SIMD prefix id */ 161 162 if (insn->prefixes.bytes[3]) 163 return inat_get_last_prefix_id(insn->prefixes.bytes[3]); 164 165 return 0; 166 } 167 168 /* Offset of each field from kaddr */ 169 static inline int insn_offset_rex_prefix(struct insn *insn) 170 { 171 return insn->prefixes.nbytes; 172 } 173 static inline int insn_offset_vex_prefix(struct insn *insn) 174 { 175 return insn_offset_rex_prefix(insn) + insn->rex_prefix.nbytes; 176 } 177 static inline int insn_offset_opcode(struct insn *insn) 178 { 179 return insn_offset_vex_prefix(insn) + insn->vex_prefix.nbytes; 180 } 181 static inline int insn_offset_modrm(struct insn *insn) 182 { 183 return insn_offset_opcode(insn) + insn->opcode.nbytes; 184 } 185 static inline int insn_offset_sib(struct insn *insn) 186 { 187 return insn_offset_modrm(insn) + insn->modrm.nbytes; 188 } 189 static inline int insn_offset_displacement(struct insn *insn) 190 { 191 return insn_offset_sib(insn) + insn->sib.nbytes; 192 } 193 static inline int insn_offset_immediate(struct insn *insn) 194 { 195 return insn_offset_displacement(insn) + insn->displacement.nbytes; 196 } 197 198 #define POP_SS_OPCODE 0x1f 199 #define MOV_SREG_OPCODE 0x8e 200 201 /* 202 * Intel SDM Vol.3A 6.8.3 states; 203 * "Any single-step trap that would be delivered following the MOV to SS 204 * instruction or POP to SS instruction (because EFLAGS.TF is 1) is 205 * suppressed." 206 * This function returns true if @insn is MOV SS or POP SS. On these 207 * instructions, single stepping is suppressed. 208 */ 209 static inline int insn_masking_exception(struct insn *insn) 210 { 211 return insn->opcode.bytes[0] == POP_SS_OPCODE || 212 (insn->opcode.bytes[0] == MOV_SREG_OPCODE && 213 X86_MODRM_REG(insn->modrm.bytes[0]) == 2); 214 } 215 216 #endif /* _ASM_X86_INSN_H */ 217