arch/x86/include/asm/insn.h

   1 #ifndef _ASM_X86_INSN_H
   2 #define _ASM_X86_INSN_H
   3 /*
   4  * x86 instruction analysis
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  *
  20  * Copyright (C) IBM Corporation, 2009
  21  */
  22
  23 /* insn_attr_t is defined in inat.h */
  24 #include <asm/inat.h>
  25
  26 struct insn_field {
  27         union {
  28                 insn_value_t value;
  29                 insn_byte_t bytes[4];
  30         };
  31         /* !0 if we've run insn_get_xxx() for this field */
  32         unsigned char got;
  33         unsigned char nbytes;
  34 };
  35
  36 struct insn {
  37         struct insn_field prefixes;     /*
  38                                          * Prefixes
  39                                          * prefixes.bytes[3]: last prefix
  40                                          */
  41         struct insn_field rex_prefix;   /* REX prefix */
  42         struct insn_field vex_prefix;   /* VEX prefix */
  43         struct insn_field opcode;       /*
  44                                          * opcode.bytes[0]: opcode1
  45                                          * opcode.bytes[1]: opcode2
  46                                          * opcode.bytes[2]: opcode3
  47                                          */
  48         struct insn_field modrm;
  49         struct insn_field sib;
  50         struct insn_field displacement;
  51         union {
  52                 struct insn_field immediate;
  53                 struct insn_field moffset1;     /* for 64bit MOV */
  54                 struct insn_field immediate1;   /* for 64bit imm or off16/32 */
  55         };
  56         union {
  57                 struct insn_field moffset2;     /* for 64bit MOV */
  58                 struct insn_field immediate2;   /* for 64bit imm or seg16 */
  59         };
  60
  61         insn_attr_t attr;
  62         unsigned char opnd_bytes;
  63         unsigned char addr_bytes;
  64         unsigned char length;
  65         unsigned char x86_64;
  66
  67         const insn_byte_t *kaddr;       /* kernel address of insn to analyze */
  68         const insn_byte_t *end_kaddr;   /* kernel address of last insn in buffer */
  69         const insn_byte_t *next_byte;
  70 };
  71
  72 #define MAX_INSN_SIZE   15
  73
  74 #define X86_MODRM_MOD(modrm) (((modrm) & 0xc0) >> 6)
  75 #define X86_MODRM_REG(modrm) (((modrm) & 0x38) >> 3)
  76 #define X86_MODRM_RM(modrm) ((modrm) & 0x07)
  77
  78 #define X86_SIB_SCALE(sib) (((sib) & 0xc0) >> 6)
  79 #define X86_SIB_INDEX(sib) (((sib) & 0x38) >> 3)
  80 #define X86_SIB_BASE(sib) ((sib) & 0x07)
  81
  82 #define X86_REX_W(rex) ((rex) & 8)
  83 #define X86_REX_R(rex) ((rex) & 4)
  84 #define X86_REX_X(rex) ((rex) & 2)
  85 #define X86_REX_B(rex) ((rex) & 1)
  86
  87 /* VEX bit flags  */
  88 #define X86_VEX_W(vex)  ((vex) & 0x80)  /* VEX3 Byte2 */
  89 #define X86_VEX_R(vex)  ((vex) & 0x80)  /* VEX2/3 Byte1 */
  90 #define X86_VEX_X(vex)  ((vex) & 0x40)  /* VEX3 Byte1 */
  91 #define X86_VEX_B(vex)  ((vex) & 0x20)  /* VEX3 Byte1 */
  92 #define X86_VEX_L(vex)  ((vex) & 0x04)  /* VEX3 Byte2, VEX2 Byte1 */
  93 /* VEX bit fields */
  94 #define X86_EVEX_M(vex) ((vex) & 0x03)          /* EVEX Byte1 */
  95 #define X86_VEX3_M(vex) ((vex) & 0x1f)          /* VEX3 Byte1 */
  96 #define X86_VEX2_M      1                       /* VEX2.M always 1 */
  97 #define X86_VEX_V(vex)  (((vex) & 0x78) >> 3)   /* VEX3 Byte2, VEX2 Byte1 */
  98 #define X86_VEX_P(vex)  ((vex) & 0x03)          /* VEX3 Byte2, VEX2 Byte1 */
  99 #define X86_VEX_M_MAX   0x1f                    /* VEX3.M Maximum value */
 100
 101 extern void insn_init(struct insn *insn, const void *kaddr, int buf_len, int x86_64);
 102 extern void insn_get_prefixes(struct insn *insn);
 103 extern void insn_get_opcode(struct insn *insn);
 104 extern void insn_get_modrm(struct insn *insn);
 105 extern void insn_get_sib(struct insn *insn);
 106 extern void insn_get_displacement(struct insn *insn);
 107 extern void insn_get_immediate(struct insn *insn);
 108 extern void insn_get_length(struct insn *insn);
 109
 110 /* Attribute will be determined after getting ModRM (for opcode groups) */
 111 static inline void insn_get_attribute(struct insn *insn)
 112 {
 113         insn_get_modrm(insn);
 114 }
 115
 116 /* Instruction uses RIP-relative addressing */
 117 extern int insn_rip_relative(struct insn *insn);
 118
 119 /* Init insn for kernel text */
 120 static inline void kernel_insn_init(struct insn *insn,
 121                                     const void *kaddr, int buf_len)
 122 {
 123 #ifdef CONFIG_X86_64
 124         insn_init(insn, kaddr, buf_len, 1);
 125 #else /* CONFIG_X86_32 */
 126         insn_init(insn, kaddr, buf_len, 0);
 127 #endif
 128 }
 129
 130 static inline int insn_is_avx(struct insn *insn)
 131 {
 132         if (!insn->prefixes.got)
 133                 insn_get_prefixes(insn);
 134         return (insn->vex_prefix.value != 0);
 135 }
 136
 137 static inline int insn_is_evex(struct insn *insn)
 138 {
 139         if (!insn->prefixes.got)
 140                 insn_get_prefixes(insn);
 141         return (insn->vex_prefix.nbytes == 4);
 142 }
 143
 144 /* Ensure this instruction is decoded completely */
 145 static inline int insn_complete(struct insn *insn)
 146 {
 147         return insn->opcode.got && insn->modrm.got && insn->sib.got &&
 148                 insn->displacement.got && insn->immediate.got;
 149 }
 150
 151 static inline insn_byte_t insn_vex_m_bits(struct insn *insn)
 152 {
 153         if (insn->vex_prefix.nbytes == 2)       /* 2 bytes VEX */
 154                 return X86_VEX2_M;
 155         else if (insn->vex_prefix.nbytes == 3)  /* 3 bytes VEX */
 156                 return X86_VEX3_M(insn->vex_prefix.bytes[1]);
 157         else                                    /* EVEX */
 158                 return X86_EVEX_M(insn->vex_prefix.bytes[1]);
 159 }
 160
 161 static inline insn_byte_t insn_vex_p_bits(struct insn *insn)
 162 {
 163         if (insn->vex_prefix.nbytes == 2)       /* 2 bytes VEX */
 164                 return X86_VEX_P(insn->vex_prefix.bytes[1]);
 165         else
 166                 return X86_VEX_P(insn->vex_prefix.bytes[2]);
 167 }
 168
 169 /* Get the last prefix id from last prefix or VEX prefix */
 170 static inline int insn_last_prefix_id(struct insn *insn)
 171 {
 172         if (insn_is_avx(insn))
 173                 return insn_vex_p_bits(insn);   /* VEX_p is a SIMD prefix id */
 174
 175         if (insn->prefixes.bytes[3])
 176                 return inat_get_last_prefix_id(insn->prefixes.bytes[3]);
 177
 178         return 0;
 179 }
 180
 181 /* Offset of each field from kaddr */
 182 static inline int insn_offset_rex_prefix(struct insn *insn)
 183 {
 184         return insn->prefixes.nbytes;
 185 }
 186 static inline int insn_offset_vex_prefix(struct insn *insn)
 187 {
 188         return insn_offset_rex_prefix(insn) + insn->rex_prefix.nbytes;
 189 }
 190 static inline int insn_offset_opcode(struct insn *insn)
 191 {
 192         return insn_offset_vex_prefix(insn) + insn->vex_prefix.nbytes;
 193 }
 194 static inline int insn_offset_modrm(struct insn *insn)
 195 {
 196         return insn_offset_opcode(insn) + insn->opcode.nbytes;
 197 }
 198 static inline int insn_offset_sib(struct insn *insn)
 199 {
 200         return insn_offset_modrm(insn) + insn->modrm.nbytes;
 201 }
 202 static inline int insn_offset_displacement(struct insn *insn)
 203 {
 204         return insn_offset_sib(insn) + insn->sib.nbytes;
 205 }
 206 static inline int insn_offset_immediate(struct insn *insn)
 207 {
 208         return insn_offset_displacement(insn) + insn->displacement.nbytes;
 209 }
 210
 211 #define POP_SS_OPCODE 0x1f
 212 #define MOV_SREG_OPCODE 0x8e
 213
 214 /*
 215  * Intel SDM Vol.3A 6.8.3 states;
 216  * "Any single-step trap that would be delivered following the MOV to SS
 217  * instruction or POP to SS instruction (because EFLAGS.TF is 1) is
 218  * suppressed."
 219  * This function returns true if @insn is MOV SS or POP SS. On these
 220  * instructions, single stepping is suppressed.
 221  */
 222 static inline int insn_masking_exception(struct insn *insn)
 223 {
 224         return insn->opcode.bytes[0] == POP_SS_OPCODE ||
 225                 (insn->opcode.bytes[0] == MOV_SREG_OPCODE &&
 226                  X86_MODRM_REG(insn->modrm.bytes[0]) == 2);
 227 }
 228
 229 #endif /* _ASM_X86_INSN_H */