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 int emulate_prefix_size; 49 insn_attr_t attr; 50 unsigned char opnd_bytes; 51 unsigned char addr_bytes; 52 unsigned char length; 53 unsigned char x86_64; 54 55 const insn_byte_t *kaddr; /* kernel address of insn to analyze */ 56 const insn_byte_t *end_kaddr; /* kernel address of last insn in buffer */ 57 const insn_byte_t *next_byte; 58 }; 59 60 #define MAX_INSN_SIZE 15 61 62 #define X86_MODRM_MOD(modrm) (((modrm) & 0xc0) >> 6) 63 #define X86_MODRM_REG(modrm) (((modrm) & 0x38) >> 3) 64 #define X86_MODRM_RM(modrm) ((modrm) & 0x07) 65 66 #define X86_SIB_SCALE(sib) (((sib) & 0xc0) >> 6) 67 #define X86_SIB_INDEX(sib) (((sib) & 0x38) >> 3) 68 #define X86_SIB_BASE(sib) ((sib) & 0x07) 69 70 #define X86_REX_W(rex) ((rex) & 8) 71 #define X86_REX_R(rex) ((rex) & 4) 72 #define X86_REX_X(rex) ((rex) & 2) 73 #define X86_REX_B(rex) ((rex) & 1) 74 75 /* VEX bit flags */ 76 #define X86_VEX_W(vex) ((vex) & 0x80) /* VEX3 Byte2 */ 77 #define X86_VEX_R(vex) ((vex) & 0x80) /* VEX2/3 Byte1 */ 78 #define X86_VEX_X(vex) ((vex) & 0x40) /* VEX3 Byte1 */ 79 #define X86_VEX_B(vex) ((vex) & 0x20) /* VEX3 Byte1 */ 80 #define X86_VEX_L(vex) ((vex) & 0x04) /* VEX3 Byte2, VEX2 Byte1 */ 81 /* VEX bit fields */ 82 #define X86_EVEX_M(vex) ((vex) & 0x03) /* EVEX Byte1 */ 83 #define X86_VEX3_M(vex) ((vex) & 0x1f) /* VEX3 Byte1 */ 84 #define X86_VEX2_M 1 /* VEX2.M always 1 */ 85 #define X86_VEX_V(vex) (((vex) & 0x78) >> 3) /* VEX3 Byte2, VEX2 Byte1 */ 86 #define X86_VEX_P(vex) ((vex) & 0x03) /* VEX3 Byte2, VEX2 Byte1 */ 87 #define X86_VEX_M_MAX 0x1f /* VEX3.M Maximum value */ 88 89 extern void insn_init(struct insn *insn, const void *kaddr, int buf_len, int x86_64); 90 extern void insn_get_prefixes(struct insn *insn); 91 extern void insn_get_opcode(struct insn *insn); 92 extern void insn_get_modrm(struct insn *insn); 93 extern void insn_get_sib(struct insn *insn); 94 extern void insn_get_displacement(struct insn *insn); 95 extern void insn_get_immediate(struct insn *insn); 96 extern void insn_get_length(struct insn *insn); 97 98 /* Attribute will be determined after getting ModRM (for opcode groups) */ 99 static inline void insn_get_attribute(struct insn *insn) 100 { 101 insn_get_modrm(insn); 102 } 103 104 /* Instruction uses RIP-relative addressing */ 105 extern int insn_rip_relative(struct insn *insn); 106 107 /* Init insn for kernel text */ 108 static inline void kernel_insn_init(struct insn *insn, 109 const void *kaddr, int buf_len) 110 { 111 #ifdef CONFIG_X86_64 112 insn_init(insn, kaddr, buf_len, 1); 113 #else /* CONFIG_X86_32 */ 114 insn_init(insn, kaddr, buf_len, 0); 115 #endif 116 } 117 118 static inline int insn_is_avx(struct insn *insn) 119 { 120 if (!insn->prefixes.got) 121 insn_get_prefixes(insn); 122 return (insn->vex_prefix.value != 0); 123 } 124 125 static inline int insn_is_evex(struct insn *insn) 126 { 127 if (!insn->prefixes.got) 128 insn_get_prefixes(insn); 129 return (insn->vex_prefix.nbytes == 4); 130 } 131 132 static inline int insn_has_emulate_prefix(struct insn *insn) 133 { 134 return !!insn->emulate_prefix_size; 135 } 136 137 /* Ensure this instruction is decoded completely */ 138 static inline int insn_complete(struct insn *insn) 139 { 140 return insn->opcode.got && insn->modrm.got && insn->sib.got && 141 insn->displacement.got && insn->immediate.got; 142 } 143 144 static inline insn_byte_t insn_vex_m_bits(struct insn *insn) 145 { 146 if (insn->vex_prefix.nbytes == 2) /* 2 bytes VEX */ 147 return X86_VEX2_M; 148 else if (insn->vex_prefix.nbytes == 3) /* 3 bytes VEX */ 149 return X86_VEX3_M(insn->vex_prefix.bytes[1]); 150 else /* EVEX */ 151 return X86_EVEX_M(insn->vex_prefix.bytes[1]); 152 } 153 154 static inline insn_byte_t insn_vex_p_bits(struct insn *insn) 155 { 156 if (insn->vex_prefix.nbytes == 2) /* 2 bytes VEX */ 157 return X86_VEX_P(insn->vex_prefix.bytes[1]); 158 else 159 return X86_VEX_P(insn->vex_prefix.bytes[2]); 160 } 161 162 /* Get the last prefix id from last prefix or VEX prefix */ 163 static inline int insn_last_prefix_id(struct insn *insn) 164 { 165 if (insn_is_avx(insn)) 166 return insn_vex_p_bits(insn); /* VEX_p is a SIMD prefix id */ 167 168 if (insn->prefixes.bytes[3]) 169 return inat_get_last_prefix_id(insn->prefixes.bytes[3]); 170 171 return 0; 172 } 173 174 /* Offset of each field from kaddr */ 175 static inline int insn_offset_rex_prefix(struct insn *insn) 176 { 177 return insn->prefixes.nbytes; 178 } 179 static inline int insn_offset_vex_prefix(struct insn *insn) 180 { 181 return insn_offset_rex_prefix(insn) + insn->rex_prefix.nbytes; 182 } 183 static inline int insn_offset_opcode(struct insn *insn) 184 { 185 return insn_offset_vex_prefix(insn) + insn->vex_prefix.nbytes; 186 } 187 static inline int insn_offset_modrm(struct insn *insn) 188 { 189 return insn_offset_opcode(insn) + insn->opcode.nbytes; 190 } 191 static inline int insn_offset_sib(struct insn *insn) 192 { 193 return insn_offset_modrm(insn) + insn->modrm.nbytes; 194 } 195 static inline int insn_offset_displacement(struct insn *insn) 196 { 197 return insn_offset_sib(insn) + insn->sib.nbytes; 198 } 199 static inline int insn_offset_immediate(struct insn *insn) 200 { 201 return insn_offset_displacement(insn) + insn->displacement.nbytes; 202 } 203 204 /** 205 * for_each_insn_prefix() -- Iterate prefixes in the instruction 206 * @insn: Pointer to struct insn. 207 * @idx: Index storage. 208 * @prefix: Prefix byte. 209 * 210 * Iterate prefix bytes of given @insn. Each prefix byte is stored in @prefix 211 * and the index is stored in @idx (note that this @idx is just for a cursor, 212 * do not change it.) 213 * Since prefixes.nbytes can be bigger than 4 if some prefixes 214 * are repeated, it cannot be used for looping over the prefixes. 215 */ 216 #define for_each_insn_prefix(insn, idx, prefix) \ 217 for (idx = 0; idx < ARRAY_SIZE(insn->prefixes.bytes) && (prefix = insn->prefixes.bytes[idx]) != 0; idx++) 218 219 #define POP_SS_OPCODE 0x1f 220 #define MOV_SREG_OPCODE 0x8e 221 222 /* 223 * Intel SDM Vol.3A 6.8.3 states; 224 * "Any single-step trap that would be delivered following the MOV to SS 225 * instruction or POP to SS instruction (because EFLAGS.TF is 1) is 226 * suppressed." 227 * This function returns true if @insn is MOV SS or POP SS. On these 228 * instructions, single stepping is suppressed. 229 */ 230 static inline int insn_masking_exception(struct insn *insn) 231 { 232 return insn->opcode.bytes[0] == POP_SS_OPCODE || 233 (insn->opcode.bytes[0] == MOV_SREG_OPCODE && 234 X86_MODRM_REG(insn->modrm.bytes[0]) == 2); 235 } 236 237 #endif /* _ASM_X86_INSN_H */ 238