ncv/ncdecode.h

   1 /*
   2  * Copyright 2008, Google Inc.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met:
   8  *
   9  *     * Redistributions of source code must retain the above copyright
  10  * notice, this list of conditions and the following disclaimer.
  11  *     * Redistributions in binary form must reproduce the above
  12  * copyright notice, this list of conditions and the following disclaimer
  13  * in the documentation and/or other materials provided with the
  14  * distribution.
  15  *     * Neither the name of Google Inc. nor the names of its
  16  * contributors may be used to endorse or promote products derived from
  17  * this software without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  22  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  23  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  29  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * ncdecode.h - table driven decoder for Native Client.
  34  *
  35  * This header file contains type declarations and constants
  36  * used by the decoder input table
  37  */
  38 #ifndef __NCDECODE_H__
  39 #define __NCDECODE_H__
  40 #include "native_client/include/portability.h"
  41
  42 struct NCDecoderState;
  43 struct NCValidatorState;
  44 /* Function type for a decoder action */
  45 typedef void (*NCDecoderAction)(const struct NCDecoderState *mstate);
  46 typedef void (*NCDecoderStats)(struct NCValidatorState *vstate);
  47
  48 /* Using a bit mask here. Hopefully nobody will be offended.
  49  * Prefix usage: 0x2e and 0x3e are used as branch prediction hints
  50  *               0x64 and 0x65 needed for TLS
  51  *               0x26 and 0x36 shouldn't be needed
  52  * These are #defines, not const ints, because they are used
  53  * for array initialization
  54  */
  55 #define kPrefixSEGCS  0x0001  /* 0x2e */
  56 #define kPrefixSEGSS  0x0002  /* 0x36 */
  57 #define kPrefixSEGFS  0x0004  /* 0x64 */
  58 #define kPrefixSEGGS  0x0008  /* 0x65 */
  59 #define kPrefixDATA16 0x0010  /* 0x66 - OKAY */
  60 #define kPrefixADDR16 0x0020  /* 0x67 - disallowed */
  61 #define kPrefixREPNE  0x0040  /* 0xf2 - OKAY */
  62 #define kPrefixREP    0x0080  /* 0xf3 - OKAY */
  63 #define kPrefixLOCK   0x0100  /* 0xf0 - OKAY */
  64 #define kPrefixSEGES  0x0200  /* 0x26 - disallowed */
  65 #define kPrefixSEGDS  0x0400  /* 0x3e - disallowed */
  66
  67 /* a new enumerated type for instructions */
  68 typedef enum {
  69   NACLi_UNDEFINED=0,  /* uninitialized space; should never happen */
  70   NACLi_ILLEGAL,      /* not allowed in NaCl */
  71   NACLi_INVALID,      /* not valid on any known x86 */
  72   NACLi_SYSTEM,       /* ring-0 instruction, not allowed in NaCl */
  73   NACLi_386,          /* an allowed instruction on all i386 implementations */
  74   NACLi_386L,         /* subset of i386 that allows LOCK prefix */
  75   NACLi_386R,         /* subset of i386 that allow REP prefix */
  76   NACLi_386RE,        /* subset of i386 that allow REPE/REPZ prefixes */
  77   NACLi_JMP8,
  78   NACLi_JMPZ,
  79   NACLi_INDIRECT,
  80   NACLi_OPINMRM,
  81   NACLi_RETURN,
  82   NACLi_CFLUSH,
  83   NACLi_CMPXCHG8B,
  84   NACLi_CMPXCHG16B,   /* 64-bit mode only, illegal for NaCl */
  85   NACLi_CMOV,
  86   NACLi_RDMSR,
  87   NACLi_RDTSC,
  88   NACLi_RDTSCP,  /* AMD only */
  89   NACLi_SYSCALL, /* AMD only; equivalent to SYSENTER */
  90   NACLi_SYSENTER,
  91   NACLi_X87,
  92   NACLi_MMX,
  93   NACLi_MMXSSE2, /* MMX with no prefix, SSE2 with 0x66 prefix */
  94   NACLi_3DNOW,   /* AMD only */
  95   NACLi_EMMX,    /* Cyrix only; not supported yet */
  96   NACLi_E3DNOW,  /* AMD only */
  97   NACLi_SSE,
  98   NACLi_SSE2,    /* no prefix => MMX; prefix 66 => SSE; */
  99                  /* f2, f3 not allowed unless used for opcode selection */
 100   NACLi_SSE2x,   /* SSE2; prefix 66 required!!! */
 101   NACLi_SSE3,
 102   NACLi_SSE4A,   /* AMD only */
 103   NACLi_SSE41,
 104   NACLi_SSE42,
 105   NACLi_MOVBE,
 106   NACLi_POPCNT,
 107   NACLi_LZCNT,
 108   NACLi_LONGMODE,/* AMD only? */
 109   NACLi_SVM,     /* AMD only */
 110   NACLi_SSSE3,
 111   NACLi_3BYTE,
 112   NACLi_FCMOV
 113   /* NOTE: This enum must be kept consistent with kNaClInstTypeRange   */
 114   /* (defined below) and with the string constants in ncdecode_table.c */
 115 } NaClInstType;
 116 #define kNaClInstTypeRange 43
 117 #ifdef NEEDSNACLINSTTYPESTRING
 118 static const char *kNaClInstTypeString[kNaClInstTypeRange] = {
 119   "NACLi_UNDEFINED",
 120   "NACLi_ILLEGAL",
 121   "NACLi_INVALID",
 122   "NACLi_SYSTEM",
 123   "NACLi_386",
 124   "NACLi_386L",
 125   "NACLi_386R",
 126   "NACLi_386RE",
 127   "NACLi_JMP8",
 128   "NACLi_JMPZ",
 129   "NACLi_INDIRECT",
 130   "NACLi_OPINMRM",
 131   "NACLi_RETURN",
 132   "NACLi_CFLUSH",
 133   "NACLi_CMPXCHG8B",
 134   "NACLi_CMPXCHG16B",
 135   "NACLi_CMOV",
 136   "NACLi_RDMSR",
 137   "NACLi_RDTSC",
 138   "NACLi_RDTSCP",
 139   "NACLi_SYSCALL",
 140   "NACLi_SYSENTER",
 141   "NACLi_X87",
 142   "NACLi_MMX",
 143   "NACLi_MMXSSE2",
 144   "NACLi_3DNOW",
 145   "NACLi_EMMX",
 146   "NACLi_E3DNOW",
 147   "NACLi_SSE",
 148   "NACLi_SSE2",
 149   "NACLi_SSE2x",
 150   "NACLi_SSE3",
 151   "NACLi_SSE4A",
 152   "NACLi_SSE41",
 153   "NACLi_SSE42",
 154   "NACLi_MOVBE",
 155   "NACLi_POPCNT",
 156   "NACLi_LZCNT",
 157   "NACLi_LONGMODE",
 158   "NACLi_SVM",
 159   "NACLi_SSSE3",
 160   "NACLi_3BYTE",
 161   "NACLi_FCMOV",
 162 };
 163 #define NaClInstTypeString(itype)  (kNaClInstTypeString[itype])
 164 #endif  /* ifdef NEEDSNACLINSTTYPESTRING */
 165
 166 typedef enum {
 167   NOGROUP=0,
 168   GROUP1,
 169   GROUP2,
 170   GROUP3,
 171   GROUP4,
 172   /* these comments facilitate counting */
 173   GROUP5,
 174   GROUP6,
 175   GROUP7,
 176   GROUP8,
 177   GROUP9,
 178   /* these comments facilitate counting */
 179   GROUP10,
 180   GROUP11,
 181   GROUP12,
 182   GROUP13,
 183   GROUP14,
 184   /* these comments facilitate counting */
 185   GROUP15,
 186   GROUP16,
 187   GROUP17,
 188   GROUP1A,
 189   GROUPP
 190 } NaClMRMGroups;
 191 /* kModRMOpcodeGroups doesn't work as a const int since it is used */
 192 /* as an array dimension */
 193 #define kNaClMRMGroupsRange 20
 194 #define kModRMOpcodeGroupSize 8
 195
 196 /* information derived from the opcode, wherever it happens to be */
 197 typedef enum {
 198   IMM_UNKNOWN=0,
 199   IMM_NONE=1,
 200   IMM_FIXED1=2,
 201   IMM_FIXED2=3,
 202   IMM_FIXED3=4,
 203   IMM_FIXED4=5,
 204   IMM_DATAV=6,
 205   IMM_ADDRV=7,
 206   IMM_GROUP3_F6=8,
 207   IMM_GROUP3_F7=9,
 208   IMM_FARPTR=10
 209   /* Don't add to this enum without update kNCDecodeImmediateTypeRange */
 210   /* and updating the tables below which are sized using this constant */
 211 } NCDecodeImmediateType;
 212 #define kNCDecodeImmediateTypeRange 11
 213
 214 /* 255 will force an error */
 215 static const uint8_t kImmTypeToSize66[kNCDecodeImmediateTypeRange] =
 216   { 0, 0, 1, 2, 3, 4, 2, 4, 0, 0, 6 };
 217 static const uint8_t kImmTypeToSize67[kNCDecodeImmediateTypeRange] =
 218   { 0, 0, 1, 2, 3, 4, 4, 2, 0, 0, 4 };
 219 static const uint8_t kImmTypeToSize[kNCDecodeImmediateTypeRange] =
 220   { 0, 0, 1, 2, 3, 4, 4, 4, 0, 0, 6 };
 221
 222 #define NCDTABLESIZE 256
 223 struct OpInfo {
 224   NaClInstType insttype;
 225   uint8_t hasmrmbyte;   /* 1 if this inst has an mrm byte, else 0 */
 226   uint8_t immtype;      /* IMM_NONE, IMM_FIXED1, etc. */
 227   uint8_t opinmrm;      /* set to 1..8 if you must find opcode in MRM byte */
 228 };
 229
 230 struct InstInfo {
 231   uint32_t vaddr;
 232   uint8_t *maddr;
 233   uint8_t prefixbytes;  /* 0..4 */
 234   uint8_t hasopbyte2;
 235   uint8_t hasopbyte3;
 236   uint8_t hassibbyte;
 237   uint8_t mrm;
 238   uint8_t immtype;
 239   uint8_t dispbytes;
 240   uint8_t length;
 241   uint32_t prefixmask;
 242 };
 243
 244 struct NCDecoderState {
 245   uint8_t *mpc;
 246   uint8_t *nextbyte;
 247   uint8_t dbindex;  /* index into decodebuffer */
 248   uint32_t vpc;
 249   const struct OpInfo *opinfo;
 250   struct InstInfo inst;
 251   struct NCValidatorState *vstate;
 252   /* The decodebuffer is an array of size kDecodeBufferSize */
 253   /* of NCDecoderState records, used to allow the validator */
 254   /* to inspect a small number of previous instructions.    */
 255   /* It is allocated on the stack to make it thread-local,  */
 256   /* and included here for use by PreviousInst().           */
 257   struct NCDecoderState *decodebuffer;
 258 };
 259
 260 /* We track machine state in a three-entry circular buffer,
 261  * allowing us to see the two previous instructions and to
 262  * check the safe call sequence. I rounded up to a power of
 263  * four so we can use a mask, even though we only need to
 264  * remember three instructions.
 265  * This is #defined rather than const int because it is used
 266  * as an array dimension
 267  */
 268 #define kDecodeBufferSize 4
 269 static const int kTwoByteOpcodeByte1 = 0x0f;
 270 static const int k3DNowOpcodeByte2 = 0x0f;
 271 static const int kMaxPrefixBytes = 4;
 272
 273 /* Some essential non-macros... */
 274 static INLINE uint8_t modrm_mod(uint8_t modrm) {  return ((modrm >> 6) & 0x03);}
 275 static INLINE uint8_t modrm_rm(uint8_t modrm) {  return (modrm & 0x07); }
 276 static INLINE uint8_t modrm_reg(uint8_t modrm) {  return ((modrm >> 3) & 0x07); }
 277 static INLINE uint8_t modrm_opcode(uint8_t modrm) {  return modrm_reg(modrm); }
 278 static INLINE uint8_t sib_ss(uint8_t sib) {  return ((sib >> 6) & 0x03); }
 279 static INLINE uint8_t sib_index(uint8_t sib) {  return ((sib >> 3) & 0x07); }
 280 static INLINE uint8_t sib_base(uint8_t sib) {  return (sib & 0x07); }
 281
 282 extern void NCDecodeRegisterCallbacks(NCDecoderAction decoderaction,
 283                                       NCDecoderStats newsegment,
 284                                       NCDecoderStats segmentationerror,
 285                                       NCDecoderStats internalerror);
 286
 287 extern void NCDecodeSegment(uint8_t *mbase, uint32_t vbase, size_t sz,
 288                             struct NCValidatorState *vstate);
 289
 290 extern struct NCDecoderState *PreviousInst(const struct NCDecoderState *mstate,
 291                                            int nindex);
 292
 293 #endif /* __NCDECODE_H__ */