Pileus Git - ~andy/linux/blob - 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 #include <linux/random.h>
  16
  17 /*
  18  * Conventions :
  19  *  EAX : BPF A accumulator
  20  *  EBX : BPF X accumulator
  21  *  RDI : pointer to skb   (first argument given to JIT function)
  22  *  RBP : frame pointer (even if CONFIG_FRAME_POINTER=n)
  23  *  ECX,EDX,ESI : scratch registers
  24  *  r9d : skb->len - skb->data_len (headlen)
  25  *  r8  : skb->data
  26  * -8(RBP) : saved RBX value
  27  * -16(RBP)..-80(RBP) : BPF_MEMWORDS values
  28  */
  29 int bpf_jit_enable __read_mostly;
  30
  31 /*
  32  * assembly code in arch/x86/net/bpf_jit.S
  33  */
  34 extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[];
  35 extern u8 sk_load_word_positive_offset[], sk_load_half_positive_offset[];
  36 extern u8 sk_load_byte_positive_offset[], sk_load_byte_msh_positive_offset[];
  37 extern u8 sk_load_word_negative_offset[], sk_load_half_negative_offset[];
  38 extern u8 sk_load_byte_negative_offset[], sk_load_byte_msh_negative_offset[];
  39
  40 static inline u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
  41 {
  42         if (len == 1)
  43                 *ptr = bytes;
  44         else if (len == 2)
  45                 *(u16 *)ptr = bytes;
  46         else {
  47                 *(u32 *)ptr = bytes;
  48                 barrier();
  49         }
  50         return ptr + len;
  51 }
  52
  53 #define EMIT(bytes, len)        do { prog = emit_code(prog, bytes, len); } while (0)
  54
  55 #define EMIT1(b1)               EMIT(b1, 1)
  56 #define EMIT2(b1, b2)           EMIT((b1) + ((b2) << 8), 2)
  57 #define EMIT3(b1, b2, b3)       EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3)
  58 #define EMIT4(b1, b2, b3, b4)   EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4)
  59 #define EMIT1_off32(b1, off)    do { EMIT1(b1); EMIT(off, 4);} while (0)
  60
  61 #define CLEAR_A() EMIT2(0x31, 0xc0) /* xor %eax,%eax */
  62 #define CLEAR_X() EMIT2(0x31, 0xdb) /* xor %ebx,%ebx */
  63
  64 static inline bool is_imm8(int value)
  65 {
  66         return value <= 127 && value >= -128;
  67 }
  68
  69 static inline bool is_near(int offset)
  70 {
  71         return offset <= 127 && offset >= -128;
  72 }
  73
  74 #define EMIT_JMP(offset)                                                \
  75 do {                                                                    \
  76         if (offset) {                                                   \
  77                 if (is_near(offset))                                    \
  78                         EMIT2(0xeb, offset); /* jmp .+off8 */           \
  79                 else                                                    \
  80                         EMIT1_off32(0xe9, offset); /* jmp .+off32 */    \
  81         }                                                               \
  82 } while (0)
  83
  84 /* list of x86 cond jumps opcodes (. + s8)
  85  * Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32)
  86  */
  87 #define X86_JB  0x72
  88 #define X86_JAE 0x73
  89 #define X86_JE  0x74
  90 #define X86_JNE 0x75
  91 #define X86_JBE 0x76
  92 #define X86_JA  0x77
  93
  94 #define EMIT_COND_JMP(op, offset)                               \
  95 do {                                                            \
  96         if (is_near(offset))                                    \
  97                 EMIT2(op, offset); /* jxx .+off8 */             \
  98         else {                                                  \
  99                 EMIT2(0x0f, op + 0x10);                         \
 100                 EMIT(offset, 4); /* jxx .+off32 */              \
 101         }                                                       \
 102 } while (0)
 103
 104 #define COND_SEL(CODE, TOP, FOP)        \
 105         case CODE:                      \
 106                 t_op = TOP;             \
 107                 f_op = FOP;             \
 108                 goto cond_branch
 109
 110
 111 #define SEEN_DATAREF 1 /* might call external helpers */
 112 #define SEEN_XREG    2 /* ebx is used */
 113 #define SEEN_MEM     4 /* use mem[] for temporary storage */
 114
 115 static inline void bpf_flush_icache(void *start, void *end)
 116 {
 117         mm_segment_t old_fs = get_fs();
 118
 119         set_fs(KERNEL_DS);
 120         smp_wmb();
 121         flush_icache_range((unsigned long)start, (unsigned long)end);
 122         set_fs(old_fs);
 123 }
 124
 125 #define CHOOSE_LOAD_FUNC(K, func) \
 126         ((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative_offset : func) : func##_positive_offset)
 127
 128 /* Helper to find the offset of pkt_type in sk_buff
 129  * We want to make sure its still a 3bit field starting at a byte boundary.
 130  */
 131 #define PKT_TYPE_MAX 7
 132 static int pkt_type_offset(void)
 133 {
 134         struct sk_buff skb_probe = {
 135                 .pkt_type = ~0,
 136         };
 137         char *ct = (char *)&skb_probe;
 138         unsigned int off;
 139
 140         for (off = 0; off < sizeof(struct sk_buff); off++) {
 141                 if (ct[off] == PKT_TYPE_MAX)
 142                         return off;
 143         }
 144         pr_err_once("Please fix pkt_type_offset(), as pkt_type couldn't be found\n");
 145         return -1;
 146 }
 147
 148 struct bpf_binary_header {
 149         unsigned int    pages;
 150         /* Note : for security reasons, bpf code will follow a randomly
 151          * sized amount of int3 instructions
 152          */
 153         u8              image[];
 154 };
 155
 156 static struct bpf_binary_header *bpf_alloc_binary(unsigned int proglen,
 157                                                   u8 **image_ptr)
 158 {
 159         unsigned int sz, hole;
 160         struct bpf_binary_header *header;
 161
 162         /* Most of BPF filters are really small,
 163          * but if some of them fill a page, allow at least
 164          * 128 extra bytes to insert a random section of int3
 165          */
 166         sz = round_up(proglen + sizeof(*header) + 128, PAGE_SIZE);
 167         header = module_alloc(sz);
 168         if (!header)
 169                 return NULL;
 170
 171         memset(header, 0xcc, sz); /* fill whole space with int3 instructions */
 172
 173         header->pages = sz / PAGE_SIZE;
 174         hole = sz - (proglen + sizeof(*header));
 175
 176         /* insert a random number of int3 instructions before BPF code */
 177         *image_ptr = &header->image[prandom_u32() % hole];
 178         return header;
 179 }
 180
 181 void bpf_jit_compile(struct sk_filter *fp)
 182 {
 183         u8 temp[64];
 184         u8 *prog;
 185         unsigned int proglen, oldproglen = 0;
 186         int ilen, i;
 187         int t_offset, f_offset;
 188         u8 t_op, f_op, seen = 0, pass;
 189         u8 *image = NULL;
 190         struct bpf_binary_header *header = NULL;
 191         u8 *func;
 192         int pc_ret0 = -1; /* bpf index of first RET #0 instruction (if any) */
 193         unsigned int cleanup_addr; /* epilogue code offset */
 194         unsigned int *addrs;
 195         const struct sock_filter *filter = fp->insns;
 196         int flen = fp->len;
 197
 198         if (!bpf_jit_enable)
 199                 return;
 200
 201         addrs = kmalloc(flen * sizeof(*addrs), GFP_KERNEL);
 202         if (addrs == NULL)
 203                 return;
 204
 205         /* Before first pass, make a rough estimation of addrs[]
 206          * each bpf instruction is translated to less than 64 bytes
 207          */
 208         for (proglen = 0, i = 0; i < flen; i++) {
 209                 proglen += 64;
 210                 addrs[i] = proglen;
 211         }
 212         cleanup_addr = proglen; /* epilogue address */
 213
 214         for (pass = 0; pass < 10; pass++) {
 215                 u8 seen_or_pass0 = (pass == 0) ? (SEEN_XREG | SEEN_DATAREF | SEEN_MEM) : seen;
 216                 /* no prologue/epilogue for trivial filters (RET something) */
 217                 proglen = 0;
 218                 prog = temp;
 219
 220                 if (seen_or_pass0) {
 221                         EMIT4(0x55, 0x48, 0x89, 0xe5); /* push %rbp; mov %rsp,%rbp */
 222                         EMIT4(0x48, 0x83, 0xec, 96);    /* subq  $96,%rsp       */
 223                         /* note : must save %rbx in case bpf_error is hit */
 224                         if (seen_or_pass0 & (SEEN_XREG | SEEN_DATAREF))
 225                                 EMIT4(0x48, 0x89, 0x5d, 0xf8); /* mov %rbx, -8(%rbp) */
 226                         if (seen_or_pass0 & SEEN_XREG)
 227                                 CLEAR_X(); /* make sure we dont leek kernel memory */
 228
 229                         /*
 230                          * If this filter needs to access skb data,
 231                          * loads r9 and r8 with :
 232                          *  r9 = skb->len - skb->data_len
 233                          *  r8 = skb->data
 234                          */
 235                         if (seen_or_pass0 & SEEN_DATAREF) {
 236                                 if (offsetof(struct sk_buff, len) <= 127)
 237                                         /* mov    off8(%rdi),%r9d */
 238                                         EMIT4(0x44, 0x8b, 0x4f, offsetof(struct sk_buff, len));
 239                                 else {
 240                                         /* mov    off32(%rdi),%r9d */
 241                                         EMIT3(0x44, 0x8b, 0x8f);
 242                                         EMIT(offsetof(struct sk_buff, len), 4);
 243                                 }
 244                                 if (is_imm8(offsetof(struct sk_buff, data_len)))
 245                                         /* sub    off8(%rdi),%r9d */
 246                                         EMIT4(0x44, 0x2b, 0x4f, offsetof(struct sk_buff, data_len));
 247                                 else {
 248                                         EMIT3(0x44, 0x2b, 0x8f);
 249                                         EMIT(offsetof(struct sk_buff, data_len), 4);
 250                                 }
 251
 252                                 if (is_imm8(offsetof(struct sk_buff, data)))
 253                                         /* mov off8(%rdi),%r8 */
 254                                         EMIT4(0x4c, 0x8b, 0x47, offsetof(struct sk_buff, data));
 255                                 else {
 256                                         /* mov off32(%rdi),%r8 */
 257                                         EMIT3(0x4c, 0x8b, 0x87);
 258                                         EMIT(offsetof(struct sk_buff, data), 4);
 259                                 }
 260                         }
 261                 }
 262
 263                 switch (filter[0].code) {
 264                 case BPF_S_RET_K:
 265                 case BPF_S_LD_W_LEN:
 266                 case BPF_S_ANC_PROTOCOL:
 267                 case BPF_S_ANC_IFINDEX:
 268                 case BPF_S_ANC_MARK:
 269                 case BPF_S_ANC_RXHASH:
 270                 case BPF_S_ANC_CPU:
 271                 case BPF_S_ANC_VLAN_TAG:
 272                 case BPF_S_ANC_VLAN_TAG_PRESENT:
 273                 case BPF_S_ANC_QUEUE:
 274                 case BPF_S_ANC_PKTTYPE:
 275                 case BPF_S_LD_W_ABS:
 276                 case BPF_S_LD_H_ABS:
 277                 case BPF_S_LD_B_ABS:
 278                         /* first instruction sets A register (or is RET 'constant') */
 279                         break;
 280                 default:
 281                         /* make sure we dont leak kernel information to user */
 282                         CLEAR_A(); /* A = 0 */
 283                 }
 284
 285                 for (i = 0; i < flen; i++) {
 286                         unsigned int K = filter[i].k;
 287
 288                         switch (filter[i].code) {
 289                         case BPF_S_ALU_ADD_X: /* A += X; */
 290                                 seen |= SEEN_XREG;
 291                                 EMIT2(0x01, 0xd8);              /* add %ebx,%eax */
 292                                 break;
 293                         case BPF_S_ALU_ADD_K: /* A += K; */
 294                                 if (!K)
 295                                         break;
 296                                 if (is_imm8(K))
 297                                         EMIT3(0x83, 0xc0, K);   /* add imm8,%eax */
 298                                 else
 299                                         EMIT1_off32(0x05, K);   /* add imm32,%eax */
 300                                 break;
 301                         case BPF_S_ALU_SUB_X: /* A -= X; */
 302                                 seen |= SEEN_XREG;
 303                                 EMIT2(0x29, 0xd8);              /* sub    %ebx,%eax */
 304                                 break;
 305                         case BPF_S_ALU_SUB_K: /* A -= K */
 306                                 if (!K)
 307                                         break;
 308                                 if (is_imm8(K))
 309                                         EMIT3(0x83, 0xe8, K); /* sub imm8,%eax */
 310                                 else
 311                                         EMIT1_off32(0x2d, K); /* sub imm32,%eax */
 312                                 break;
 313                         case BPF_S_ALU_MUL_X: /* A *= X; */
 314                                 seen |= SEEN_XREG;
 315                                 EMIT3(0x0f, 0xaf, 0xc3);        /* imul %ebx,%eax */
 316                                 break;
 317                         case BPF_S_ALU_MUL_K: /* A *= K */
 318                                 if (is_imm8(K))
 319                                         EMIT3(0x6b, 0xc0, K); /* imul imm8,%eax,%eax */
 320                                 else {
 321                                         EMIT2(0x69, 0xc0);              /* imul imm32,%eax */
 322                                         EMIT(K, 4);
 323                                 }
 324                                 break;
 325                         case BPF_S_ALU_DIV_X: /* A /= X; */
 326                                 seen |= SEEN_XREG;
 327                                 EMIT2(0x85, 0xdb);      /* test %ebx,%ebx */
 328                                 if (pc_ret0 > 0) {
 329                                         /* addrs[pc_ret0 - 1] is start address of target
 330                                          * (addrs[i] - 4) is the address following this jmp
 331                                          * ("xor %edx,%edx; div %ebx" being 4 bytes long)
 332                                          */
 333                                         EMIT_COND_JMP(X86_JE, addrs[pc_ret0 - 1] -
 334                                                                 (addrs[i] - 4));
 335                                 } else {
 336                                         EMIT_COND_JMP(X86_JNE, 2 + 5);
 337                                         CLEAR_A();
 338                                         EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 4)); /* jmp .+off32 */
 339                                 }
 340                                 EMIT4(0x31, 0xd2, 0xf7, 0xf3); /* xor %edx,%edx; div %ebx */
 341                                 break;
 342                         case BPF_S_ALU_MOD_X: /* A %= X; */
 343                                 seen |= SEEN_XREG;
 344                                 EMIT2(0x85, 0xdb);      /* test %ebx,%ebx */
 345                                 if (pc_ret0 > 0) {
 346                                         /* addrs[pc_ret0 - 1] is start address of target
 347                                          * (addrs[i] - 6) is the address following this jmp
 348                                          * ("xor %edx,%edx; div %ebx;mov %edx,%eax" being 6 bytes long)
 349                                          */
 350                                         EMIT_COND_JMP(X86_JE, addrs[pc_ret0 - 1] -
 351                                                                 (addrs[i] - 6));
 352                                 } else {
 353                                         EMIT_COND_JMP(X86_JNE, 2 + 5);
 354                                         CLEAR_A();
 355                                         EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 6)); /* jmp .+off32 */
 356                                 }
 357                                 EMIT2(0x31, 0xd2);      /* xor %edx,%edx */
 358                                 EMIT2(0xf7, 0xf3);      /* div %ebx */
 359                                 EMIT2(0x89, 0xd0);      /* mov %edx,%eax */
 360                                 break;
 361                         case BPF_S_ALU_MOD_K: /* A %= K; */
 362                                 EMIT2(0x31, 0xd2);      /* xor %edx,%edx */
 363                                 EMIT1(0xb9);EMIT(K, 4); /* mov imm32,%ecx */
 364                                 EMIT2(0xf7, 0xf1);      /* div %ecx */
 365                                 EMIT2(0x89, 0xd0);      /* mov %edx,%eax */
 366                                 break;
 367                         case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K); */
 368                                 EMIT3(0x48, 0x69, 0xc0); /* imul imm32,%rax,%rax */
 369                                 EMIT(K, 4);
 370                                 EMIT4(0x48, 0xc1, 0xe8, 0x20); /* shr $0x20,%rax */
 371                                 break;
 372                         case BPF_S_ALU_AND_X:
 373                                 seen |= SEEN_XREG;
 374                                 EMIT2(0x21, 0xd8);              /* and %ebx,%eax */
 375                                 break;
 376                         case BPF_S_ALU_AND_K:
 377                                 if (K >= 0xFFFFFF00) {
 378                                         EMIT2(0x24, K & 0xFF); /* and imm8,%al */
 379                                 } else if (K >= 0xFFFF0000) {
 380                                         EMIT2(0x66, 0x25);      /* and imm16,%ax */
 381                                         EMIT(K, 2);
 382                                 } else {
 383                                         EMIT1_off32(0x25, K);   /* and imm32,%eax */
 384                                 }
 385                                 break;
 386                         case BPF_S_ALU_OR_X:
 387                                 seen |= SEEN_XREG;
 388                                 EMIT2(0x09, 0xd8);              /* or %ebx,%eax */
 389                                 break;
 390                         case BPF_S_ALU_OR_K:
 391                                 if (is_imm8(K))
 392                                         EMIT3(0x83, 0xc8, K); /* or imm8,%eax */
 393                                 else
 394                                         EMIT1_off32(0x0d, K);   /* or imm32,%eax */
 395                                 break;
 396                         case BPF_S_ANC_ALU_XOR_X: /* A ^= X; */
 397                         case BPF_S_ALU_XOR_X:
 398                                 seen |= SEEN_XREG;
 399                                 EMIT2(0x31, 0xd8);              /* xor %ebx,%eax */
 400                                 break;
 401                         case BPF_S_ALU_XOR_K: /* A ^= K; */
 402                                 if (K == 0)
 403                                         break;
 404                                 if (is_imm8(K))
 405                                         EMIT3(0x83, 0xf0, K);   /* xor imm8,%eax */
 406                                 else
 407                                         EMIT1_off32(0x35, K);   /* xor imm32,%eax */
 408                                 break;
 409                         case BPF_S_ALU_LSH_X: /* A <<= X; */
 410                                 seen |= SEEN_XREG;
 411                                 EMIT4(0x89, 0xd9, 0xd3, 0xe0);  /* mov %ebx,%ecx; shl %cl,%eax */
 412                                 break;
 413                         case BPF_S_ALU_LSH_K:
 414                                 if (K == 0)
 415                                         break;
 416                                 else if (K == 1)
 417                                         EMIT2(0xd1, 0xe0); /* shl %eax */
 418                                 else
 419                                         EMIT3(0xc1, 0xe0, K);
 420                                 break;
 421                         case BPF_S_ALU_RSH_X: /* A >>= X; */
 422                                 seen |= SEEN_XREG;
 423                                 EMIT4(0x89, 0xd9, 0xd3, 0xe8);  /* mov %ebx,%ecx; shr %cl,%eax */
 424                                 break;
 425                         case BPF_S_ALU_RSH_K: /* A >>= K; */
 426                                 if (K == 0)
 427                                         break;
 428                                 else if (K == 1)
 429                                         EMIT2(0xd1, 0xe8); /* shr %eax */
 430                                 else
 431                                         EMIT3(0xc1, 0xe8, K);
 432                                 break;
 433                         case BPF_S_ALU_NEG:
 434                                 EMIT2(0xf7, 0xd8);              /* neg %eax */
 435                                 break;
 436                         case BPF_S_RET_K:
 437                                 if (!K) {
 438                                         if (pc_ret0 == -1)
 439                                                 pc_ret0 = i;
 440                                         CLEAR_A();
 441                                 } else {
 442                                         EMIT1_off32(0xb8, K);   /* mov $imm32,%eax */
 443                                 }
 444                                 /* fallinto */
 445                         case BPF_S_RET_A:
 446                                 if (seen_or_pass0) {
 447                                         if (i != flen - 1) {
 448                                                 EMIT_JMP(cleanup_addr - addrs[i]);
 449                                                 break;
 450                                         }
 451                                         if (seen_or_pass0 & SEEN_XREG)
 452                                                 EMIT4(0x48, 0x8b, 0x5d, 0xf8);  /* mov  -8(%rbp),%rbx */
 453                                         EMIT1(0xc9);            /* leaveq */
 454                                 }
 455                                 EMIT1(0xc3);            /* ret */
 456                                 break;
 457                         case BPF_S_MISC_TAX: /* X = A */
 458                                 seen |= SEEN_XREG;
 459                                 EMIT2(0x89, 0xc3);      /* mov    %eax,%ebx */
 460                                 break;
 461                         case BPF_S_MISC_TXA: /* A = X */
 462                                 seen |= SEEN_XREG;
 463                                 EMIT2(0x89, 0xd8);      /* mov    %ebx,%eax */
 464                                 break;
 465                         case BPF_S_LD_IMM: /* A = K */
 466                                 if (!K)
 467                                         CLEAR_A();
 468                                 else
 469                                         EMIT1_off32(0xb8, K); /* mov $imm32,%eax */
 470                                 break;
 471                         case BPF_S_LDX_IMM: /* X = K */
 472                                 seen |= SEEN_XREG;
 473                                 if (!K)
 474                                         CLEAR_X();
 475                                 else
 476                                         EMIT1_off32(0xbb, K); /* mov $imm32,%ebx */
 477                                 break;
 478                         case BPF_S_LD_MEM: /* A = mem[K] : mov off8(%rbp),%eax */
 479                                 seen |= SEEN_MEM;
 480                                 EMIT3(0x8b, 0x45, 0xf0 - K*4);
 481                                 break;
 482                         case BPF_S_LDX_MEM: /* X = mem[K] : mov off8(%rbp),%ebx */
 483                                 seen |= SEEN_XREG | SEEN_MEM;
 484                                 EMIT3(0x8b, 0x5d, 0xf0 - K*4);
 485                                 break;
 486                         case BPF_S_ST: /* mem[K] = A : mov %eax,off8(%rbp) */
 487                                 seen |= SEEN_MEM;
 488                                 EMIT3(0x89, 0x45, 0xf0 - K*4);
 489                                 break;
 490                         case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
 491                                 seen |= SEEN_XREG | SEEN_MEM;
 492                                 EMIT3(0x89, 0x5d, 0xf0 - K*4);
 493                                 break;
 494                         case BPF_S_LD_W_LEN: /* A = skb->len; */
 495                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
 496                                 if (is_imm8(offsetof(struct sk_buff, len)))
 497                                         /* mov    off8(%rdi),%eax */
 498                                         EMIT3(0x8b, 0x47, offsetof(struct sk_buff, len));
 499                                 else {
 500                                         EMIT2(0x8b, 0x87);
 501                                         EMIT(offsetof(struct sk_buff, len), 4);
 502                                 }
 503                                 break;
 504                         case BPF_S_LDX_W_LEN: /* X = skb->len; */
 505                                 seen |= SEEN_XREG;
 506                                 if (is_imm8(offsetof(struct sk_buff, len)))
 507                                         /* mov off8(%rdi),%ebx */
 508                                         EMIT3(0x8b, 0x5f, offsetof(struct sk_buff, len));
 509                                 else {
 510                                         EMIT2(0x8b, 0x9f);
 511                                         EMIT(offsetof(struct sk_buff, len), 4);
 512                                 }
 513                                 break;
 514                         case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
 515                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
 516                                 if (is_imm8(offsetof(struct sk_buff, protocol))) {
 517                                         /* movzwl off8(%rdi),%eax */
 518                                         EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, protocol));
 519                                 } else {
 520                                         EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
 521                                         EMIT(offsetof(struct sk_buff, protocol), 4);
 522                                 }
 523                                 EMIT2(0x86, 0xc4); /* ntohs() : xchg   %al,%ah */
 524                                 break;
 525                         case BPF_S_ANC_IFINDEX:
 526                                 if (is_imm8(offsetof(struct sk_buff, dev))) {
 527                                         /* movq off8(%rdi),%rax */
 528                                         EMIT4(0x48, 0x8b, 0x47, offsetof(struct sk_buff, dev));
 529                                 } else {
 530                                         EMIT3(0x48, 0x8b, 0x87); /* movq off32(%rdi),%rax */
 531                                         EMIT(offsetof(struct sk_buff, dev), 4);
 532                                 }
 533                                 EMIT3(0x48, 0x85, 0xc0);        /* test %rax,%rax */
 534                                 EMIT_COND_JMP(X86_JE, cleanup_addr - (addrs[i] - 6));
 535                                 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
 536                                 EMIT2(0x8b, 0x80);      /* mov off32(%rax),%eax */
 537                                 EMIT(offsetof(struct net_device, ifindex), 4);
 538                                 break;
 539                         case BPF_S_ANC_MARK:
 540                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
 541                                 if (is_imm8(offsetof(struct sk_buff, mark))) {
 542                                         /* mov off8(%rdi),%eax */
 543                                         EMIT3(0x8b, 0x47, offsetof(struct sk_buff, mark));
 544                                 } else {
 545                                         EMIT2(0x8b, 0x87);
 546                                         EMIT(offsetof(struct sk_buff, mark), 4);
 547                                 }
 548                                 break;
 549                         case BPF_S_ANC_RXHASH:
 550                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4);
 551                                 if (is_imm8(offsetof(struct sk_buff, rxhash))) {
 552                                         /* mov off8(%rdi),%eax */
 553                                         EMIT3(0x8b, 0x47, offsetof(struct sk_buff, rxhash));
 554                                 } else {
 555                                         EMIT2(0x8b, 0x87);
 556                                         EMIT(offsetof(struct sk_buff, rxhash), 4);
 557                                 }
 558                                 break;
 559                         case BPF_S_ANC_QUEUE:
 560                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
 561                                 if (is_imm8(offsetof(struct sk_buff, queue_mapping))) {
 562                                         /* movzwl off8(%rdi),%eax */
 563                                         EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, queue_mapping));
 564                                 } else {
 565                                         EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
 566                                         EMIT(offsetof(struct sk_buff, queue_mapping), 4);
 567                                 }
 568                                 break;
 569                         case BPF_S_ANC_CPU:
 570 #ifdef CONFIG_SMP
 571                                 EMIT4(0x65, 0x8b, 0x04, 0x25); /* mov %gs:off32,%eax */
 572                                 EMIT((u32)(unsigned long)&cpu_number, 4); /* A = smp_processor_id(); */
 573 #else
 574                                 CLEAR_A();
 575 #endif
 576                                 break;
 577                         case BPF_S_ANC_VLAN_TAG:
 578                         case BPF_S_ANC_VLAN_TAG_PRESENT:
 579                                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
 580                                 if (is_imm8(offsetof(struct sk_buff, vlan_tci))) {
 581                                         /* movzwl off8(%rdi),%eax */
 582                                         EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, vlan_tci));
 583                                 } else {
 584                                         EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
 585                                         EMIT(offsetof(struct sk_buff, vlan_tci), 4);
 586                                 }
 587                                 BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
 588                                 if (filter[i].code == BPF_S_ANC_VLAN_TAG) {
 589                                         EMIT3(0x80, 0xe4, 0xef); /* and    $0xef,%ah */
 590                                 } else {
 591                                         EMIT3(0xc1, 0xe8, 0x0c); /* shr    $0xc,%eax */
 592                                         EMIT3(0x83, 0xe0, 0x01); /* and    $0x1,%eax */
 593                                 }
 594                                 break;
 595                         case BPF_S_ANC_PKTTYPE:
 596                         {
 597                                 int off = pkt_type_offset();
 598
 599                                 if (off < 0)
 600                                         goto out;
 601                                 if (is_imm8(off)) {
 602                                         /* movzbl off8(%rdi),%eax */
 603                                         EMIT4(0x0f, 0xb6, 0x47, off);
 604                                 } else {
 605                                         /* movbl off32(%rdi),%eax */
 606                                         EMIT3(0x0f, 0xb6, 0x87);
 607                                         EMIT(off, 4);
 608                                 }
 609                                 EMIT3(0x83, 0xe0, PKT_TYPE_MAX); /* and    $0x7,%eax */
 610                                 break;
 611                         }
 612                         case BPF_S_LD_W_ABS:
 613                                 func = CHOOSE_LOAD_FUNC(K, sk_load_word);
 614 common_load:                    seen |= SEEN_DATAREF;
 615                                 t_offset = func - (image + addrs[i]);
 616                                 EMIT1_off32(0xbe, K); /* mov imm32,%esi */
 617                                 EMIT1_off32(0xe8, t_offset); /* call */
 618                                 break;
 619                         case BPF_S_LD_H_ABS:
 620                                 func = CHOOSE_LOAD_FUNC(K, sk_load_half);
 621                                 goto common_load;
 622                         case BPF_S_LD_B_ABS:
 623                                 func = CHOOSE_LOAD_FUNC(K, sk_load_byte);
 624                                 goto common_load;
 625                         case BPF_S_LDX_B_MSH:
 626                                 func = CHOOSE_LOAD_FUNC(K, sk_load_byte_msh);
 627                                 seen |= SEEN_DATAREF | SEEN_XREG;
 628                                 t_offset = func - (image + addrs[i]);
 629                                 EMIT1_off32(0xbe, K);   /* mov imm32,%esi */
 630                                 EMIT1_off32(0xe8, t_offset); /* call sk_load_byte_msh */
 631                                 break;
 632                         case BPF_S_LD_W_IND:
 633                                 func = sk_load_word;
 634 common_load_ind:                seen |= SEEN_DATAREF | SEEN_XREG;
 635                                 t_offset = func - (image + addrs[i]);
 636                                 if (K) {
 637                                         if (is_imm8(K)) {
 638                                                 EMIT3(0x8d, 0x73, K); /* lea imm8(%rbx), %esi */
 639                                         } else {
 640                                                 EMIT2(0x8d, 0xb3); /* lea imm32(%rbx),%esi */
 641                                                 EMIT(K, 4);
 642                                         }
 643                                 } else {
 644                                         EMIT2(0x89,0xde); /* mov %ebx,%esi */
 645                                 }
 646                                 EMIT1_off32(0xe8, t_offset);    /* call sk_load_xxx_ind */
 647                                 break;
 648                         case BPF_S_LD_H_IND:
 649                                 func = sk_load_half;
 650                                 goto common_load_ind;
 651                         case BPF_S_LD_B_IND:
 652                                 func = sk_load_byte;
 653                                 goto common_load_ind;
 654                         case BPF_S_JMP_JA:
 655                                 t_offset = addrs[i + K] - addrs[i];
 656                                 EMIT_JMP(t_offset);
 657                                 break;
 658                         COND_SEL(BPF_S_JMP_JGT_K, X86_JA, X86_JBE);
 659                         COND_SEL(BPF_S_JMP_JGE_K, X86_JAE, X86_JB);
 660                         COND_SEL(BPF_S_JMP_JEQ_K, X86_JE, X86_JNE);
 661                         COND_SEL(BPF_S_JMP_JSET_K,X86_JNE, X86_JE);
 662                         COND_SEL(BPF_S_JMP_JGT_X, X86_JA, X86_JBE);
 663                         COND_SEL(BPF_S_JMP_JGE_X, X86_JAE, X86_JB);
 664                         COND_SEL(BPF_S_JMP_JEQ_X, X86_JE, X86_JNE);
 665                         COND_SEL(BPF_S_JMP_JSET_X,X86_JNE, X86_JE);
 666
 667 cond_branch:                    f_offset = addrs[i + filter[i].jf] - addrs[i];
 668                                 t_offset = addrs[i + filter[i].jt] - addrs[i];
 669
 670                                 /* same targets, can avoid doing the test :) */
 671                                 if (filter[i].jt == filter[i].jf) {
 672                                         EMIT_JMP(t_offset);
 673                                         break;
 674                                 }
 675
 676                                 switch (filter[i].code) {
 677                                 case BPF_S_JMP_JGT_X:
 678                                 case BPF_S_JMP_JGE_X:
 679                                 case BPF_S_JMP_JEQ_X:
 680                                         seen |= SEEN_XREG;
 681                                         EMIT2(0x39, 0xd8); /* cmp %ebx,%eax */
 682                                         break;
 683                                 case BPF_S_JMP_JSET_X:
 684                                         seen |= SEEN_XREG;
 685                                         EMIT2(0x85, 0xd8); /* test %ebx,%eax */
 686                                         break;
 687                                 case BPF_S_JMP_JEQ_K:
 688                                         if (K == 0) {
 689                                                 EMIT2(0x85, 0xc0); /* test   %eax,%eax */
 690                                                 break;
 691                                         }
 692                                 case BPF_S_JMP_JGT_K:
 693                                 case BPF_S_JMP_JGE_K:
 694                                         if (K <= 127)
 695                                                 EMIT3(0x83, 0xf8, K); /* cmp imm8,%eax */
 696                                         else
 697                                                 EMIT1_off32(0x3d, K); /* cmp imm32,%eax */
 698                                         break;
 699                                 case BPF_S_JMP_JSET_K:
 700                                         if (K <= 0xFF)
 701                                                 EMIT2(0xa8, K); /* test imm8,%al */
 702                                         else if (!(K & 0xFFFF00FF))
 703                                                 EMIT3(0xf6, 0xc4, K >> 8); /* test imm8,%ah */
 704                                         else if (K <= 0xFFFF) {
 705                                                 EMIT2(0x66, 0xa9); /* test imm16,%ax */
 706                                                 EMIT(K, 2);
 707                                         } else {
 708                                                 EMIT1_off32(0xa9, K); /* test imm32,%eax */
 709                                         }
 710                                         break;
 711                                 }
 712                                 if (filter[i].jt != 0) {
 713                                         if (filter[i].jf && f_offset)
 714                                                 t_offset += is_near(f_offset) ? 2 : 5;
 715                                         EMIT_COND_JMP(t_op, t_offset);
 716                                         if (filter[i].jf)
 717                                                 EMIT_JMP(f_offset);
 718                                         break;
 719                                 }
 720                                 EMIT_COND_JMP(f_op, f_offset);
 721                                 break;
 722                         default:
 723                                 /* hmm, too complex filter, give up with jit compiler */
 724                                 goto out;
 725                         }
 726                         ilen = prog - temp;
 727                         if (image) {
 728                                 if (unlikely(proglen + ilen > oldproglen)) {
 729                                         pr_err("bpb_jit_compile fatal error\n");
 730                                         kfree(addrs);
 731                                         module_free(NULL, header);
 732                                         return;
 733                                 }
 734                                 memcpy(image + proglen, temp, ilen);
 735                         }
 736                         proglen += ilen;
 737                         addrs[i] = proglen;
 738                         prog = temp;
 739                 }
 740                 /* last bpf instruction is always a RET :
 741                  * use it to give the cleanup instruction(s) addr
 742                  */
 743                 cleanup_addr = proglen - 1; /* ret */
 744                 if (seen_or_pass0)
 745                         cleanup_addr -= 1; /* leaveq */
 746                 if (seen_or_pass0 & SEEN_XREG)
 747                         cleanup_addr -= 4; /* mov  -8(%rbp),%rbx */
 748
 749                 if (image) {
 750                         if (proglen != oldproglen)
 751                                 pr_err("bpb_jit_compile proglen=%u != oldproglen=%u\n", proglen, oldproglen);
 752                         break;
 753                 }
 754                 if (proglen == oldproglen) {
 755                         header = bpf_alloc_binary(proglen, &image);
 756                         if (!header)
 757                                 goto out;
 758                 }
 759                 oldproglen = proglen;
 760         }
 761
 762         if (bpf_jit_enable > 1)
 763                 bpf_jit_dump(flen, proglen, pass, image);
 764
 765         if (image) {
 766                 bpf_flush_icache(header, image + proglen);
 767                 set_memory_ro((unsigned long)header, header->pages);
 768                 fp->bpf_func = (void *)image;
 769         }
 770 out:
 771         kfree(addrs);
 772         return;
 773 }
 774
 775 static void bpf_jit_free_deferred(struct work_struct *work)
 776 {
 777         struct sk_filter *fp = container_of(work, struct sk_filter, work);
 778         unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
 779         struct bpf_binary_header *header = (void *)addr;
 780
 781         set_memory_rw(addr, header->pages);
 782         module_free(NULL, header);
 783         kfree(fp);
 784 }
 785
 786 void bpf_jit_free(struct sk_filter *fp)
 787 {
 788         if (fp->bpf_func != sk_run_filter) {
 789                 INIT_WORK(&fp->work, bpf_jit_free_deferred);
 790                 schedule_work(&fp->work);
 791         } else {
 792                 kfree(fp);
 793         }
 794 }