arch/x86/net/bpf_jit_comp.c

   1 /* bpf_jit_comp.c : BPF JIT compiler
   2  *
   3  * Copyright (C) 2011-2013 Eric Dumazet (eric.dumazet@gmail.com)
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; version 2
   8  * of the License.
   9  */
  10 #include <linux/moduleloader.h>
  11 #include <asm/cacheflush.h>
  12 #include <linux/netdevice.h>
  13 #include <linux/filter.h>
  14 #include <linux/if_vlan.h>
  15
  16 /*
  17  * Conventions :
  18  *  EAX : BPF A accumulator
  19  *  EBX : BPF X accumulator
  20  *  RDI : pointer to skb   (first argument given to JIT function)
  21  *  RBP : frame pointer (even if CONFIG_FRAME_POINTER=n)
  22  *  ECX,EDX,ESI : scratch registers
  23  *  r9d : skb->len - skb->data_len (headlen)
  24  *  r8  : skb->data
  25  * -8(RBP) : saved RBX value
  26  * -16(RBP)..-80(RBP) : BPF_MEMWORDS values
  27  */
  28 int bpf_jit_enable __read_mostly;
  29
  30 /*
  31  * assembly code in arch/x86/net/bpf_jit.S
  32  */
  33 extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[];
  34 extern u8 sk_load_word_positive_offset[], sk_load_half_positive_offset[];
  35 extern u8 sk_load_byte_positive_offset[], sk_load_byte_msh_positive_offset[];
  36 extern u8 sk_load_word_negative_offset[], sk_load_half_negative_offset[];
  37 extern u8 sk_load_byte_negative_offset[], sk_load_byte_msh_negative_offset[];
  38
  39 static inline u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
  40 {
  41         if (len == 1)
  42                 *ptr = bytes;
  43         else if (len == 2)
  44                 *(u16 *)ptr = bytes;
  45         else {
  46                 *(u32 *)ptr = bytes;
  47                 barrier();
  48         }
  49         return ptr + len;
  50 }
  51
  52 #define EMIT(bytes, len)        do { prog = emit_code(prog, bytes, len); } while (0)
  53
  54 #define EMIT1(b1)               EMIT(b1, 1)
  55 #define EMIT2(b1, b2)           EMIT((b1) + ((b2) << 8), 2)
  56 #define EMIT3(b1, b2, b3)       EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3)
  57 #define EMIT4(b1, b2, b3, b4)   EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4)
  58 #define EMIT1_off32(b1, off)    do { EMIT1(b1); EMIT(off, 4);} while (0)
  59
  60 #define CLEAR_A() EMIT2(0x31, 0xc0) /* xor %eax,%eax */
  61 #define CLEAR_X() EMIT2(0x31, 0xdb) /* xor %ebx,%ebx */
  62
  63 static inline bool is_imm8(int value)
  64 {
  65         return value <= 127 && value >= -128;
  66 }
  67
  68 static inline bool is_near(int offset)
  69 {
  70         return offset <= 127 && offset >= -128;
  71 }
  72
  73 #define EMIT_JMP(offset)                                                \
  74 do {                                                                    \
  75         if (offset) {                                                   \
  76                 if (is_near(offset))                                    \
  77                         EMIT2(0xeb, offset); /* jmp .+off8 */           \
  78                 else                                                    \
  79                         EMIT1_off32(0xe9, offset); /* jmp .+off32 */    \
  80         }                                                               \
  81 } while (0)
  82
  83 /* list of x86 cond jumps opcodes (. + s8)
  84  * Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32)
  85  */
  86 #define X86_JB  0x72
  87 #define X86_JAE 0x73
  88 #define X86_JE  0x74
  89 #define X86_JNE 0x75
  90 #define X86_JBE 0x76
  91 #define X86_JA  0x77
  92
  93 #define EMIT_COND_JMP(op, offset)                               \
  94 do {                                                            \
  95         if (is_near(offset))                                    \
  96                 EMIT2(op, offset); /* jxx .+off8 */             \
  97         else {                                                  \
  98                 EMIT2(0x0f, op + 0x10);                         \
  99                 EMIT(offset, 4); /* jxx .+off32 */              \
 100         }                                                       \
 101 } while (0)
 102
 103 #define COND_SEL(CODE, TOP, FOP)        \
 104         case CODE:                      \
 105                 t_op = TOP;             \
 106                 f_op = FOP;             \
 107                 goto cond_branch
 108
 109
 110 #define SEEN_DATAREF 1 /* might call external helpers */
 111 #define SEEN_XREG    2 /* ebx is used */
 112 #define SEEN_MEM     4 /* use mem[] for temporary storage */
 113
 114 static inline void bpf_flush_icache(void *start, void *end)
 115 {
 116         mm_segment_t old_fs = get_fs();
 117
 118         set_fs(KERNEL_DS);
 119         smp_wmb();
 120         flush_icache_range((unsigned long)start, (unsigned long)end);
 121         set_fs(old_fs);
 122 }
 123
 124 #define CHOOSE_LOAD_FUNC(K, func) \
 125         ((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative_offset : func) : func##_positive_offset)
 126
 127 /* Helper to find the offset of pkt_type in sk_buff
 128  * We want to make sure its still a 3bit field starting at a byte boundary.
 129  */
 130 #define PKT_TYPE_MAX 7
 131 static int pkt_type_offset(void)
 132 {
 133         struct sk_buff skb_probe = {
 134                 .pkt_type = ~0,
 135         };
 136         char *ct = (char *)&skb_probe;
 137         unsigned int off;
 138
 139         for (off = 0; off < sizeof(struct sk_buff); off++) {
 140                 if (ct[off] == PKT_TYPE_MAX)
 141                         return off;
 142         }
 143         pr_err_once("Please fix pkt_type_offset(), as pkt_type couldn't be found\n");
 144         return -1;
 145 }
 146
 147 void bpf_jit_compile(struct sk_filter *fp)
 148 {
 149         u8 temp[64];
 150         u8 *prog;
 151         unsigned int proglen, oldproglen = 0;
 152         int ilen, i;
 153         int t_offset, f_offset;
 154         u8 t_op, f_op, seen = 0, pass;
 155         u8 *image = NULL;
 156         u8 *func;
 157         int pc_ret0 = -1; /* bpf index of first RET #0 instruction (if any) */
 158         unsigned int cleanup_addr; /* epilogue code offset */
 159         unsigned int *addrs;
 160         const struct sock_filter *filter = fp->insns;
 161         int flen = fp->len;
 162
 163         if (!bpf_jit_enable)
 164                 return;
 165
 166         addrs = kmalloc(flen * sizeof(*addrs), GFP_KERNEL);
 167         if (addrs == NULL)
 168                 return;
 169
 170         /* Before first pass, make a rough estimation of addrs[]
 171          * each bpf instruction is translated to less than 64 bytes
 172          */
 173         for (proglen = 0, i = 0; i < flen; i++) {
 174                 proglen += 64;
 175                 addrs[i] = proglen;
 176         }
 177         cleanup_addr = proglen; /* epilogue address */
 178
 179         for (pass = 0; pass < 10; pass++) {
 180                 u8 seen_or_pass0 = (pass == 0) ? (SEEN_XREG | SEEN_DATAREF | SEEN_MEM) : seen;
 181                 /* no prologue/epilogue for trivial filters (RET something) */
 182                 proglen = 0;
 183                 prog = temp;
 184
 185                 if (seen_or_pass0) {
 186                         EMIT4(0x55, 0x48, 0x89, 0xe5); /* push %rbp; mov %rsp,%rbp */
 187                         EMIT4(0x48, 0x83, 0xec, 96);    /* subq  $96,%rsp       */
 188                         /* note : must save %rbx in case bpf_error is hit */
 189                         if (seen_or_pass0 & (SEEN_XREG | SEEN_DATAREF))
 190                                 EMIT4(0x48, 0x89, 0x5d, 0xf8); /* mov %rbx, -8(%rbp) */
 191                         if (seen_or_pass0 & SEEN_XREG)
 192                                 CLEAR_X(); /* make sure we dont leek kernel memory */
 193
 194                         /*
 195                          * If this filter needs to access skb data,
 196                          * loads r9 and r8 with :
 197                          *  r9 = skb->len - skb->data_len
 198                          *  r8 = skb->data
 199                          */
 200                         if (seen_or_pass0 & SEEN_DATAREF) {
 201                                 if (offsetof(struct sk_buff, len) <= 127)
 202                                         /* mov    off8(%rdi),%r9d */
 203                                         EMIT4(0x44, 0x8b, 0x4f, offsetof(struct sk_buff, len));
 204                                 else {
 205                                         /* mov    off32(%rdi),%r9d */
 206                                         EMIT3(0x44, 0x8b, 0x8f);
 207                                         EMIT(offsetof(struct sk_buff, len), 4);
 208                                 }
 209                                 if (is_imm8(offsetof(struct sk_buff, data_len)))
 210                                         /* sub    off8(%rdi),%r9d */
 211                                         EMIT4(0x44, 0x2b, 0x4f, offsetof(struct sk_buff, data_len));
 212                                 else {
 213                                         EMIT3(0x44, 0x2b, 0x8f);
 214                                         EMIT(offsetof(struct sk_buff, data_len), 4);
 215                                 }
 216
 217                                 if (is_imm8(offsetof(struct sk_buff, data)))
 218                                         /* mov off8(%rdi),%r8 */
 219                                         EMIT4(0x4c, 0x8b, 0x47, offsetof(struct sk_buff, data));
 220                                 else {
 221                                         /* mov off32(%rdi),%r8 */
 222                                         EMIT3(0x4c, 0x8b, 0x87);
 223                                         EMIT(offsetof(struct sk_buff, data), 4);
 224                                 }
 225                         }
 226                 }
 227
 228                 switch (filter[0].code) {
 229                 case BPF_S_RET_K:
 230                 case BPF_S_LD_W_LEN:
 231                 case BPF_S_ANC_PROTOCOL:
 232                 case BPF_S_ANC_IFINDEX:
 233                 case BPF_S_ANC_MARK:
 234                 case BPF_S_ANC_RXHASH:
 235                 case BPF_S_ANC_CPU:
 236                 case BPF_S_ANC_VLAN_TAG:
 237                 case BPF_S_ANC_VLAN_TAG_PRESENT:
 238                 case BPF_S_ANC_QUEUE:
 239                 case BPF_S_ANC_PKTTYPE:
 240                 case BPF_S_LD_W_ABS:
 241                 case BPF_S_LD_H_ABS:
 242                 case BPF_S_LD_B_ABS:
 243                         /* first instruction sets A register (or is RET 'constant') */
 244                         break;
 245                 default:
 246                         /* make sure we dont leak kernel information to user */
 247                         CLEAR_A(); /* A = 0 */
 248                 }
 249
 250                 for (i = 0; i < flen; i++) {
 251                         unsigned int K = filter[i].k;
 252
 253                         switch (filter[i].code) {
 254                         case BPF_S_ALU_ADD_X: /* A += X; */
 255                                 seen |= SEEN_XREG;
 256                                 EMIT2(0x01, 0xd8);              /* add %ebx,%eax */
 257                                 break;
 258                         case BPF_S_ALU_ADD_K: /* A += K; */
 259                                 if (!K)
 260                                         break;
 261                                 if (is_imm8(K))
 262                                         EMIT3(0x83, 0xc0, K);   /* add imm8,%eax */
 263                                 else
 264                                         EMIT1_off32(0x05, K);   /* add imm32,%eax */
 265                                 break;
 266                         case BPF_S_ALU_SUB_X: /* A -= X; */
 267                                 seen |= SEEN_XREG;
 268                                 EMIT2(0x29, 0xd8);              /* sub    %ebx,%eax */
 269                                 break;
 270                         case BPF_S_ALU_SUB_K: /* A -= K */
 271                                 if (!K)
 272                                         break;
 273                                 if (is_imm8(K))
 274                                         EMIT3(0x83, 0xe8, K); /* sub imm8,%eax */
 275                                 else
 276                                         EMIT1_off32(0x2d, K); /* sub imm32,%eax */
 277                                 break;
 278                         case BPF_S_ALU_MUL_X: /* A *= X; */
 279                                 seen |= SEEN_XREG;
 280                                 EMIT3(0x0f, 0xaf, 0xc3);        /* imul %ebx,%eax */
 281                                 break;
 282                         case BPF_S_ALU_MUL_K: /* A *= K */
 283                                 if (is_imm8(K))
 284                                         EMIT3(0x6b, 0xc0, K); /* imul imm8,%eax,%eax */
 285                                 else {
 286                                         EMIT2(0x69, 0xc0);              /* imul imm32,%eax */
 287                                         EMIT(K, 4);
 288                                 }
 289                                 break;
 290                         case BPF_S_ALU_DIV_X: /* A /= X; */
 291                                 seen |= SEEN_XREG;
 292                                 EMIT2(0x85, 0xdb);      /* test %ebx,%ebx */
 293                                 if (pc_ret0 > 0) {
 294                                         /* addrs[pc_ret0 - 1] is start address of target
 295                                          * (addrs[i] - 4) is the address following this jmp
 296                                          * ("xor %edx,%edx; div %ebx" being 4 bytes long)
 297                                          */
 298                                         EMIT_COND_JMP(X86_JE, addrs[pc_ret0 - 1] -
 299                                                                 (addrs[i] - 4));
 300                                 } else {
 301                                         EMIT_COND_JMP(X86_JNE, 2 + 5);
 302                                         CLEAR_A();
 303                                         EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 4)); /* jmp .+off32 */
 304                                 }
 305                                 EMIT4(0x31, 0xd2, 0xf7, 0xf3); /* xor %edx,%edx; div %ebx */
 306                                 break;
 307                         case BPF_S_ALU_MOD_X: /* A %= X; */
 308                                 seen |= SEEN_XREG;
 309                                 EMIT2(0x85, 0xdb);      /* test %ebx,%ebx */
 310                                 if (pc_ret0 > 0) {
 311                                         /* addrs[pc_ret0 - 1] is start address of target
 312                                          * (addrs[i] - 6) is the address following this jmp
 313                                          * ("xor %edx,%edx; div %ebx;mov %edx,%eax" being 6 bytes long)
 314                                          */
 315                                         EMIT_COND_JMP(X86_JE, addrs[pc_ret0 - 1] -
 316                                                                 (addrs[i] - 6));
 317                                 } else {
 318                                         EMIT_COND_JMP(X86_JNE, 2 + 5);
 319                                         CLEAR_A();
 320                                         EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 6)); /* jmp .+off32 */
 321                                 }
 322                                 EMIT2(0x31, 0xd2);      /* xor %edx,%edx */
 323                                 EMIT2(0xf7, 0xf3);      /* div %ebx */
 324                                 EMIT2(0x89, 0xd0);      /* mov %edx,%eax */
 325                                 break;
 326                         case BPF_S_ALU_MOD_K: /* A %= K; */
 327                                 EMIT2(0x31, 0xd2);      /* xor %edx,%edx */
 328                                 EMIT1(0xb9);EMIT(K, 4); /* mov imm32,%ecx */
 329                                 EMIT2(0xf7, 0xf1);      /* div %ecx */
 330                                 EMIT2(0x89, 0xd0);      /* mov %edx,%eax */
 331                                 break;
 332                         case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K); */
 333                                 EMIT3(0x48, 0x69, 0xc0); /* imul imm32,%rax,%rax */
 334                                 EMIT(K, 4);
 335                                 EMIT4(0x48, 0xc1, 0xe8, 0x20); /* shr $0x20,%rax */
 336                                 break;
 337                         case BPF_S_ALU_AND_X:
 338                                 seen |= SEEN_XREG;
 339                                 EMIT2(0x21, 0xd8);              /* and %ebx,%eax */
 340                                 break;
 341                         case BPF_S_ALU_AND_K:
 342                                 if (K >= 0xFFFFFF00) {
 343                                         EMIT2(0x24, K & 0xFF); /* and imm8,%al */
 344                                 } else if (K >= 0xFFFF0000) {
 345                                         EMIT2(0x66, 0x25);      /* and imm16,%ax */
 346                                         EMIT(K, 2);
 347                                 } else {
 348                                         EMIT1_off32(0x25, K);   /* and imm32,%eax */
 349                                 }
 350                                 break;
 351                         case BPF_S_ALU_OR_X:
 352                                 seen |= SEEN_XREG;
 353                                 EMIT2(0x09, 0xd8);              /* or %ebx,%eax */
 354                                 break;
 355                         case BPF_S_ALU_OR_K:
 356                                 if (is_imm8(K))
 357                                         EMIT3(0x83, 0xc8, K); /* or imm8,%eax */
 358                                 else
 359                                         EMIT1_off32(0x0d, K);   /* or imm32,%eax */
 360                                 break;
 361                         case BPF_S_ANC_ALU_XOR_X: /* A ^= X; */
 362                         case BPF_S_ALU_XOR_X:
 363                                 seen |= SEEN_XREG;
 364                                 EMIT2(0x31, 0xd8);              /* xor %ebx,%eax */
 365                                 break;
 366                         case BPF_S_ALU_XOR_K: /* A ^= K; */
 367                                 if (K == 0)
 368                                         break;
 369                                 if (is_imm8(K))
 370                                         EMIT3(0x83, 0xf0, K);   /* xor imm8,%eax */
 371                                 else
 372                                         EMIT1_off32(0x35, K);   /* xor imm32,%eax */
 373                                 break;
 374                         case BPF_S_ALU_LSH_X: /* A <<= X; */
 375                                 seen |= SEEN_XREG;
 376                                 EMIT4(0x89, 0xd9, 0xd3, 0xe0);  /* mov %ebx,%ecx; shl %cl,%eax */
 377                                 break;
 378                         case BPF_S_ALU_LSH_K:
 379                                 if (K == 0)
 380                                         break;
 381                                 else if (K == 1)
 382                                         EMIT2(0xd1, 0xe0); /* shl %eax */
 383                                 else
 384                                         EMIT3(0xc1, 0xe0, K);
 385                                 break;
 386                         case BPF_S_ALU_RSH_X: /* A >>= X; */
 387                                 seen |= SEEN_XREG;
 388                                 EMIT4(0x89, 0xd9, 0xd3, 0xe8);  /* mov %ebx,%ecx; shr %cl,%eax */
 389                                 break;
 390                         case BPF_S_ALU_RSH_K: /* A >>= K; */
 391                                 if (K == 0)
 392                                         break;
 393                                 else if (K == 1)
 394                                         EMIT2(0xd1, 0xe8); /* shr %eax */
 395                                 else
 396                                         EMIT3(0xc1, 0xe8, K);
 397                                 break;
 398                         case BPF_S_ALU_NEG:
 399                                 EMIT2(0xf7, 0xd8);              /* neg %eax */
 400                                 break;
 401                         case BPF_S_RET_K:
 402                                 if (!K) {
 403                                         if (pc_ret0 == -1)
 404                                                 pc_ret0 = i;
 405                                         CLEAR_A();
 406                                 } else {
 407                                         EMIT1_off32(0xb8, K);   /* mov $imm32,%eax */
 408                                 }
 409                                 /* fallinto */
 410                         case BPF_S_RET_A:
 411                                 if (seen_or_pass0) {
 412                                         if (i != flen - 1) {
 413                                                 EMIT_JMP(cleanup_addr - addrs[i]);
 414                                                 break;
 415                                         }
 416                                         if (seen_or_pass0 & SEEN_XREG)
 417                                                 EMIT4(0x48, 0x8b, 0x5d, 0xf8);  /* mov  -8(%rbp),%rbx */
 418                                         EMIT1(0xc9);            /* leaveq */
 419                                 }
 420                                 EMIT1(0xc3);            /* ret */
 421                                 break;
 422                         case BPF_S_MISC_TAX: /* X = A */
 423                                 seen |= SEEN_XREG;
 424                                 EMIT2(0x89, 0xc3);      /* mov    %eax,%ebx */
 425                                 break;
 426                         case BPF_S_MISC_TXA: /* A = X */
 427                                 seen |= SEEN_XREG;
 428                                 EMIT2(0x89, 0xd8);      /* mov    %ebx,%eax */
 429                                 break;
 430                         case BPF_S_LD_IMM: /* A = K */
 431                                 if (!K)
 432                                         CLEAR_A();
 433                                 else
 434                                         EMIT1_off32(0xb8, K); /* mov $imm32,%eax */
 435                                 break;
 436                         case BPF_S_LDX_IMM: /* X = K */
 437                                 seen |= SEEN_XREG;
 438                                 if (!K)
 439                                         CLEAR_X();
 440                                 else
 441                                         EMIT1_off32(0xbb, K); /* mov $imm32,%ebx */
 442                                 break;
 443                         case BPF_S_LD_MEM: /* A = mem[K] : mov off8(%rbp),%eax */
 444                                 seen |= SEEN_MEM;
 445                                 EMIT3(0x8b, 0x45, 0xf0 - K*4);
 446                                 break;
 447                         case BPF_S_LDX_MEM: /* X = mem[K] : mov off8(%rbp),%ebx */
 448                                 seen |= SEEN_XREG | SEEN_MEM;
 449                                 EMIT3(0x8b, 0x5d, 0xf0 - K*4);
 450                                 break;
 451                         case BPF_S_ST: /* mem[K] = A : mov %eax,off8(%rbp) */
 452                                 seen |= SEEN_MEM;
 453                                 EMIT3(0x89, 0x45, 0xf0 - K*4);
 454                                 break;
 455                         case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
 456                                 seen |= SEEN_XREG | SEEN_MEM;
 457                                 EMIT3(0x89, 0x5d, 0xf0 - K*4);
 458                                 break;
 459                         case BPF_S_LD_W_LEN: /* A = skb->len; */
 460                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
 461                                 if (is_imm8(offsetof(struct sk_buff, len)))
 462                                         /* mov    off8(%rdi),%eax */
 463                                         EMIT3(0x8b, 0x47, offsetof(struct sk_buff, len));
 464                                 else {
 465                                         EMIT2(0x8b, 0x87);
 466                                         EMIT(offsetof(struct sk_buff, len), 4);
 467                                 }
 468                                 break;
 469                         case BPF_S_LDX_W_LEN: /* X = skb->len; */
 470                                 seen |= SEEN_XREG;
 471                                 if (is_imm8(offsetof(struct sk_buff, len)))
 472                                         /* mov off8(%rdi),%ebx */
 473                                         EMIT3(0x8b, 0x5f, offsetof(struct sk_buff, len));
 474                                 else {
 475                                         EMIT2(0x8b, 0x9f);
 476                                         EMIT(offsetof(struct sk_buff, len), 4);
 477                                 }
 478                                 break;
 479                         case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
 480                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
 481                                 if (is_imm8(offsetof(struct sk_buff, protocol))) {
 482                                         /* movzwl off8(%rdi),%eax */
 483                                         EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, protocol));
 484                                 } else {
 485                                         EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
 486                                         EMIT(offsetof(struct sk_buff, protocol), 4);
 487                                 }
 488                                 EMIT2(0x86, 0xc4); /* ntohs() : xchg   %al,%ah */
 489                                 break;
 490                         case BPF_S_ANC_IFINDEX:
 491                                 if (is_imm8(offsetof(struct sk_buff, dev))) {
 492                                         /* movq off8(%rdi),%rax */
 493                                         EMIT4(0x48, 0x8b, 0x47, offsetof(struct sk_buff, dev));
 494                                 } else {
 495                                         EMIT3(0x48, 0x8b, 0x87); /* movq off32(%rdi),%rax */
 496                                         EMIT(offsetof(struct sk_buff, dev), 4);
 497                                 }
 498                                 EMIT3(0x48, 0x85, 0xc0);        /* test %rax,%rax */
 499                                 EMIT_COND_JMP(X86_JE, cleanup_addr - (addrs[i] - 6));
 500                                 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
 501                                 EMIT2(0x8b, 0x80);      /* mov off32(%rax),%eax */
 502                                 EMIT(offsetof(struct net_device, ifindex), 4);
 503                                 break;
 504                         case BPF_S_ANC_MARK:
 505                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
 506                                 if (is_imm8(offsetof(struct sk_buff, mark))) {
 507                                         /* mov off8(%rdi),%eax */
 508                                         EMIT3(0x8b, 0x47, offsetof(struct sk_buff, mark));
 509                                 } else {
 510                                         EMIT2(0x8b, 0x87);
 511                                         EMIT(offsetof(struct sk_buff, mark), 4);
 512                                 }
 513                                 break;
 514                         case BPF_S_ANC_RXHASH:
 515                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4);
 516                                 if (is_imm8(offsetof(struct sk_buff, rxhash))) {
 517                                         /* mov off8(%rdi),%eax */
 518                                         EMIT3(0x8b, 0x47, offsetof(struct sk_buff, rxhash));
 519                                 } else {
 520                                         EMIT2(0x8b, 0x87);
 521                                         EMIT(offsetof(struct sk_buff, rxhash), 4);
 522                                 }
 523                                 break;
 524                         case BPF_S_ANC_QUEUE:
 525                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
 526                                 if (is_imm8(offsetof(struct sk_buff, queue_mapping))) {
 527                                         /* movzwl off8(%rdi),%eax */
 528                                         EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, queue_mapping));
 529                                 } else {
 530                                         EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
 531                                         EMIT(offsetof(struct sk_buff, queue_mapping), 4);
 532                                 }
 533                                 break;
 534                         case BPF_S_ANC_CPU:
 535 #ifdef CONFIG_SMP
 536                                 EMIT4(0x65, 0x8b, 0x04, 0x25); /* mov %gs:off32,%eax */
 537                                 EMIT((u32)(unsigned long)&cpu_number, 4); /* A = smp_processor_id(); */
 538 #else
 539                                 CLEAR_A();
 540 #endif
 541                                 break;
 542                         case BPF_S_ANC_VLAN_TAG:
 543                         case BPF_S_ANC_VLAN_TAG_PRESENT:
 544                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
 545                                 if (is_imm8(offsetof(struct sk_buff, vlan_tci))) {
 546                                         /* movzwl off8(%rdi),%eax */
 547                                         EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, vlan_tci));
 548                                 } else {
 549                                         EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
 550                                         EMIT(offsetof(struct sk_buff, vlan_tci), 4);
 551                                 }
 552                                 BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
 553                                 if (filter[i].code == BPF_S_ANC_VLAN_TAG) {
 554                                         EMIT3(0x80, 0xe4, 0xef); /* and    $0xef,%ah */
 555                                 } else {
 556                                         EMIT3(0xc1, 0xe8, 0x0c); /* shr    $0xc,%eax */
 557                                         EMIT3(0x83, 0xe0, 0x01); /* and    $0x1,%eax */
 558                                 }
 559                                 break;
 560                         case BPF_S_ANC_PKTTYPE:
 561                         {
 562                                 int off = pkt_type_offset();
 563
 564                                 if (off < 0)
 565                                         goto out;
 566                                 if (is_imm8(off)) {
 567                                         /* movzbl off8(%rdi),%eax */
 568                                         EMIT4(0x0f, 0xb6, 0x47, off);
 569                                 } else {
 570                                         /* movbl off32(%rdi),%eax */
 571                                         EMIT3(0x0f, 0xb6, 0x87);
 572                                         EMIT(off, 4);
 573                                 }
 574                                 EMIT3(0x83, 0xe0, PKT_TYPE_MAX); /* and    $0x7,%eax */
 575                                 break;
 576                         }
 577                         case BPF_S_LD_W_ABS:
 578                                 func = CHOOSE_LOAD_FUNC(K, sk_load_word);
 579 common_load:                    seen |= SEEN_DATAREF;
 580                                 t_offset = func - (image + addrs[i]);
 581                                 EMIT1_off32(0xbe, K); /* mov imm32,%esi */
 582                                 EMIT1_off32(0xe8, t_offset); /* call */
 583                                 break;
 584                         case BPF_S_LD_H_ABS:
 585                                 func = CHOOSE_LOAD_FUNC(K, sk_load_half);
 586                                 goto common_load;
 587                         case BPF_S_LD_B_ABS:
 588                                 func = CHOOSE_LOAD_FUNC(K, sk_load_byte);
 589                                 goto common_load;
 590                         case BPF_S_LDX_B_MSH:
 591                                 func = CHOOSE_LOAD_FUNC(K, sk_load_byte_msh);
 592                                 seen |= SEEN_DATAREF | SEEN_XREG;
 593                                 t_offset = func - (image + addrs[i]);
 594                                 EMIT1_off32(0xbe, K);   /* mov imm32,%esi */
 595                                 EMIT1_off32(0xe8, t_offset); /* call sk_load_byte_msh */
 596                                 break;
 597                         case BPF_S_LD_W_IND:
 598                                 func = sk_load_word;
 599 common_load_ind:                seen |= SEEN_DATAREF | SEEN_XREG;
 600                                 t_offset = func - (image + addrs[i]);
 601                                 if (K) {
 602                                         if (is_imm8(K)) {
 603                                                 EMIT3(0x8d, 0x73, K); /* lea imm8(%rbx), %esi */
 604                                         } else {
 605                                                 EMIT2(0x8d, 0xb3); /* lea imm32(%rbx),%esi */
 606                                                 EMIT(K, 4);
 607                                         }
 608                                 } else {
 609                                         EMIT2(0x89,0xde); /* mov %ebx,%esi */
 610                                 }
 611                                 EMIT1_off32(0xe8, t_offset);    /* call sk_load_xxx_ind */
 612                                 break;
 613                         case BPF_S_LD_H_IND:
 614                                 func = sk_load_half;
 615                                 goto common_load_ind;
 616                         case BPF_S_LD_B_IND:
 617                                 func = sk_load_byte;
 618                                 goto common_load_ind;
 619                         case BPF_S_JMP_JA:
 620                                 t_offset = addrs[i + K] - addrs[i];
 621                                 EMIT_JMP(t_offset);
 622                                 break;
 623                         COND_SEL(BPF_S_JMP_JGT_K, X86_JA, X86_JBE);
 624                         COND_SEL(BPF_S_JMP_JGE_K, X86_JAE, X86_JB);
 625                         COND_SEL(BPF_S_JMP_JEQ_K, X86_JE, X86_JNE);
 626                         COND_SEL(BPF_S_JMP_JSET_K,X86_JNE, X86_JE);
 627                         COND_SEL(BPF_S_JMP_JGT_X, X86_JA, X86_JBE);
 628                         COND_SEL(BPF_S_JMP_JGE_X, X86_JAE, X86_JB);
 629                         COND_SEL(BPF_S_JMP_JEQ_X, X86_JE, X86_JNE);
 630                         COND_SEL(BPF_S_JMP_JSET_X,X86_JNE, X86_JE);
 631
 632 cond_branch:                    f_offset = addrs[i + filter[i].jf] - addrs[i];
 633                                 t_offset = addrs[i + filter[i].jt] - addrs[i];
 634
 635                                 /* same targets, can avoid doing the test :) */
 636                                 if (filter[i].jt == filter[i].jf) {
 637                                         EMIT_JMP(t_offset);
 638                                         break;
 639                                 }
 640
 641                                 switch (filter[i].code) {
 642                                 case BPF_S_JMP_JGT_X:
 643                                 case BPF_S_JMP_JGE_X:
 644                                 case BPF_S_JMP_JEQ_X:
 645                                         seen |= SEEN_XREG;
 646                                         EMIT2(0x39, 0xd8); /* cmp %ebx,%eax */
 647                                         break;
 648                                 case BPF_S_JMP_JSET_X:
 649                                         seen |= SEEN_XREG;
 650                                         EMIT2(0x85, 0xd8); /* test %ebx,%eax */
 651                                         break;
 652                                 case BPF_S_JMP_JEQ_K:
 653                                         if (K == 0) {
 654                                                 EMIT2(0x85, 0xc0); /* test   %eax,%eax */
 655                                                 break;
 656                                         }
 657                                 case BPF_S_JMP_JGT_K:
 658                                 case BPF_S_JMP_JGE_K:
 659                                         if (K <= 127)
 660                                                 EMIT3(0x83, 0xf8, K); /* cmp imm8,%eax */
 661                                         else
 662                                                 EMIT1_off32(0x3d, K); /* cmp imm32,%eax */
 663                                         break;
 664                                 case BPF_S_JMP_JSET_K:
 665                                         if (K <= 0xFF)
 666                                                 EMIT2(0xa8, K); /* test imm8,%al */
 667                                         else if (!(K & 0xFFFF00FF))
 668                                                 EMIT3(0xf6, 0xc4, K >> 8); /* test imm8,%ah */
 669                                         else if (K <= 0xFFFF) {
 670                                                 EMIT2(0x66, 0xa9); /* test imm16,%ax */
 671                                                 EMIT(K, 2);
 672                                         } else {
 673                                                 EMIT1_off32(0xa9, K); /* test imm32,%eax */
 674                                         }
 675                                         break;
 676                                 }
 677                                 if (filter[i].jt != 0) {
 678                                         if (filter[i].jf && f_offset)
 679                                                 t_offset += is_near(f_offset) ? 2 : 5;
 680                                         EMIT_COND_JMP(t_op, t_offset);
 681                                         if (filter[i].jf)
 682                                                 EMIT_JMP(f_offset);
 683                                         break;
 684                                 }
 685                                 EMIT_COND_JMP(f_op, f_offset);
 686                                 break;
 687                         default:
 688                                 /* hmm, too complex filter, give up with jit compiler */
 689                                 goto out;
 690                         }
 691                         ilen = prog - temp;
 692                         if (image) {
 693                                 if (unlikely(proglen + ilen > oldproglen)) {
 694                                         pr_err("bpb_jit_compile fatal error\n");
 695                                         kfree(addrs);
 696                                         module_free(NULL, image);
 697                                         return;
 698                                 }
 699                                 memcpy(image + proglen, temp, ilen);
 700                         }
 701                         proglen += ilen;
 702                         addrs[i] = proglen;
 703                         prog = temp;
 704                 }
 705                 /* last bpf instruction is always a RET :
 706                  * use it to give the cleanup instruction(s) addr
 707                  */
 708                 cleanup_addr = proglen - 1; /* ret */
 709                 if (seen_or_pass0)
 710                         cleanup_addr -= 1; /* leaveq */
 711                 if (seen_or_pass0 & SEEN_XREG)
 712                         cleanup_addr -= 4; /* mov  -8(%rbp),%rbx */
 713
 714                 if (image) {
 715                         if (proglen != oldproglen)
 716                                 pr_err("bpb_jit_compile proglen=%u != oldproglen=%u\n", proglen, oldproglen);
 717                         break;
 718                 }
 719                 if (proglen == oldproglen) {
 720                         image = module_alloc(max_t(unsigned int,
 721                                                    proglen,
 722                                                    sizeof(struct work_struct)));
 723                         if (!image)
 724                                 goto out;
 725                 }
 726                 oldproglen = proglen;
 727         }
 728
 729         if (bpf_jit_enable > 1)
 730                 bpf_jit_dump(flen, proglen, pass, image);
 731
 732         if (image) {
 733                 bpf_flush_icache(image, image + proglen);
 734                 fp->bpf_func = (void *)image;
 735         }
 736 out:
 737         kfree(addrs);
 738         return;
 739 }
 740
 741 static void jit_free_defer(struct work_struct *arg)
 742 {
 743         module_free(NULL, arg);
 744 }
 745
 746 /* run from softirq, we must use a work_struct to call
 747  * module_free() from process context
 748  */
 749 void bpf_jit_free(struct sk_filter *fp)
 750 {
 751         if (fp->bpf_func != sk_run_filter) {
 752                 struct work_struct *work = (struct work_struct *)fp->bpf_func;
 753
 754                 INIT_WORK(work, jit_free_defer);
 755                 schedule_work(work);
 756         }
 757 }