arch/s390/net/bpf_jit_comp.c

   1 /*
   2  * BPF Jit compiler for s390.
   3  *
   4  * Copyright IBM Corp. 2012
   5  *
   6  * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
   7  */
   8 #include <linux/moduleloader.h>
   9 #include <linux/netdevice.h>
  10 #include <linux/filter.h>
  11 #include <asm/cacheflush.h>
  12 #include <asm/processor.h>
  13 #include <asm/facility.h>
  14
  15 /*
  16  * Conventions:
  17  *   %r2 = skb pointer
  18  *   %r3 = offset parameter
  19  *   %r4 = scratch register / length parameter
  20  *   %r5 = BPF A accumulator
  21  *   %r8 = return address
  22  *   %r9 = save register for skb pointer
  23  *   %r10 = skb->data
  24  *   %r11 = skb->len - skb->data_len (headlen)
  25  *   %r12 = BPF X accumulator
  26  *   %r13 = literal pool pointer
  27  *   0(%r15) - 63(%r15) scratch memory array with BPF_MEMWORDS
  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_ind[], sk_load_half_ind[], sk_load_byte_ind[];
  36
  37 struct bpf_jit {
  38         unsigned int seen;
  39         u8 *start;
  40         u8 *prg;
  41         u8 *mid;
  42         u8 *lit;
  43         u8 *end;
  44         u8 *base_ip;
  45         u8 *ret0_ip;
  46         u8 *exit_ip;
  47         unsigned int off_load_word;
  48         unsigned int off_load_half;
  49         unsigned int off_load_byte;
  50         unsigned int off_load_bmsh;
  51         unsigned int off_load_iword;
  52         unsigned int off_load_ihalf;
  53         unsigned int off_load_ibyte;
  54 };
  55
  56 #define BPF_SIZE_MAX    4096    /* Max size for program */
  57
  58 #define SEEN_DATAREF    1       /* might call external helpers */
  59 #define SEEN_XREG       2       /* ebx is used */
  60 #define SEEN_MEM        4       /* use mem[] for temporary storage */
  61 #define SEEN_RET0       8       /* pc_ret0 points to a valid return 0 */
  62 #define SEEN_LITERAL    16      /* code uses literals */
  63 #define SEEN_LOAD_WORD  32      /* code uses sk_load_word */
  64 #define SEEN_LOAD_HALF  64      /* code uses sk_load_half */
  65 #define SEEN_LOAD_BYTE  128     /* code uses sk_load_byte */
  66 #define SEEN_LOAD_BMSH  256     /* code uses sk_load_byte_msh */
  67 #define SEEN_LOAD_IWORD 512     /* code uses sk_load_word_ind */
  68 #define SEEN_LOAD_IHALF 1024    /* code uses sk_load_half_ind */
  69 #define SEEN_LOAD_IBYTE 2048    /* code uses sk_load_byte_ind */
  70
  71 #define EMIT2(op)                                       \
  72 ({                                                      \
  73         if (jit->prg + 2 <= jit->mid)                   \
  74                 *(u16 *) jit->prg = op;                 \
  75         jit->prg += 2;                                  \
  76 })
  77
  78 #define EMIT4(op)                                       \
  79 ({                                                      \
  80         if (jit->prg + 4 <= jit->mid)                   \
  81                 *(u32 *) jit->prg = op;                 \
  82         jit->prg += 4;                                  \
  83 })
  84
  85 #define EMIT4_DISP(op, disp)                            \
  86 ({                                                      \
  87         unsigned int __disp = (disp) & 0xfff;           \
  88         EMIT4(op | __disp);                             \
  89 })
  90
  91 #define EMIT4_IMM(op, imm)                              \
  92 ({                                                      \
  93         unsigned int __imm = (imm) & 0xffff;            \
  94         EMIT4(op | __imm);                              \
  95 })
  96
  97 #define EMIT4_PCREL(op, pcrel)                          \
  98 ({                                                      \
  99         long __pcrel = ((pcrel) >> 1) & 0xffff;         \
 100         EMIT4(op | __pcrel);                            \
 101 })
 102
 103 #define EMIT6(op1, op2)                                 \
 104 ({                                                      \
 105         if (jit->prg + 6 <= jit->mid) {                 \
 106                 *(u32 *) jit->prg = op1;                \
 107                 *(u16 *) (jit->prg + 4) = op2;          \
 108         }                                               \
 109         jit->prg += 6;                                  \
 110 })
 111
 112 #define EMIT6_DISP(op1, op2, disp)                      \
 113 ({                                                      \
 114         unsigned int __disp = (disp) & 0xfff;           \
 115         EMIT6(op1 | __disp, op2);                       \
 116 })
 117
 118 #define EMIT6_IMM(op, imm)                              \
 119 ({                                                      \
 120         unsigned int __imm = (imm);                     \
 121         EMIT6(op | (__imm >> 16), __imm & 0xffff);      \
 122 })
 123
 124 #define EMIT_CONST(val)                                 \
 125 ({                                                      \
 126         unsigned int ret;                               \
 127         ret = (unsigned int) (jit->lit - jit->base_ip); \
 128         jit->seen |= SEEN_LITERAL;                      \
 129         if (jit->lit + 4 <= jit->end)                   \
 130                 *(u32 *) jit->lit = val;                \
 131         jit->lit += 4;                                  \
 132         ret;                                            \
 133 })
 134
 135 #define EMIT_FN_CONST(bit, fn)                          \
 136 ({                                                      \
 137         unsigned int ret;                               \
 138         ret = (unsigned int) (jit->lit - jit->base_ip); \
 139         if (jit->seen & bit) {                          \
 140                 jit->seen |= SEEN_LITERAL;              \
 141                 if (jit->lit + 8 <= jit->end)           \
 142                         *(void **) jit->lit = fn;       \
 143                 jit->lit += 8;                          \
 144         }                                               \
 145         ret;                                            \
 146 })
 147
 148 static void bpf_jit_prologue(struct bpf_jit *jit)
 149 {
 150         /* Save registers and create stack frame if necessary */
 151         if (jit->seen & SEEN_DATAREF) {
 152                 /* stmg %r8,%r15,88(%r15) */
 153                 EMIT6(0xeb8ff058, 0x0024);
 154                 /* lgr %r14,%r15 */
 155                 EMIT4(0xb90400ef);
 156                 /* ahi %r15,<offset> */
 157                 EMIT4_IMM(0xa7fa0000, (jit->seen & SEEN_MEM) ? -112 : -80);
 158                 /* stg %r14,152(%r15) */
 159                 EMIT6(0xe3e0f098, 0x0024);
 160         } else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL))
 161                 /* stmg %r12,%r13,120(%r15) */
 162                 EMIT6(0xebcdf078, 0x0024);
 163         else if (jit->seen & SEEN_XREG)
 164                 /* stg %r12,120(%r15) */
 165                 EMIT6(0xe3c0f078, 0x0024);
 166         else if (jit->seen & SEEN_LITERAL)
 167                 /* stg %r13,128(%r15) */
 168                 EMIT6(0xe3d0f080, 0x0024);
 169
 170         /* Setup literal pool */
 171         if (jit->seen & SEEN_LITERAL) {
 172                 /* basr %r13,0 */
 173                 EMIT2(0x0dd0);
 174                 jit->base_ip = jit->prg;
 175         }
 176         jit->off_load_word = EMIT_FN_CONST(SEEN_LOAD_WORD, sk_load_word);
 177         jit->off_load_half = EMIT_FN_CONST(SEEN_LOAD_HALF, sk_load_half);
 178         jit->off_load_byte = EMIT_FN_CONST(SEEN_LOAD_BYTE, sk_load_byte);
 179         jit->off_load_bmsh = EMIT_FN_CONST(SEEN_LOAD_BMSH, sk_load_byte_msh);
 180         jit->off_load_iword = EMIT_FN_CONST(SEEN_LOAD_IWORD, sk_load_word_ind);
 181         jit->off_load_ihalf = EMIT_FN_CONST(SEEN_LOAD_IHALF, sk_load_half_ind);
 182         jit->off_load_ibyte = EMIT_FN_CONST(SEEN_LOAD_IBYTE, sk_load_byte_ind);
 183
 184         /* Filter needs to access skb data */
 185         if (jit->seen & SEEN_DATAREF) {
 186                 /* l %r11,<len>(%r2) */
 187                 EMIT4_DISP(0x58b02000, offsetof(struct sk_buff, len));
 188                 /* s %r11,<data_len>(%r2) */
 189                 EMIT4_DISP(0x5bb02000, offsetof(struct sk_buff, data_len));
 190                 /* lg %r10,<data>(%r2) */
 191                 EMIT6_DISP(0xe3a02000, 0x0004,
 192                            offsetof(struct sk_buff, data));
 193         }
 194 }
 195
 196 static void bpf_jit_epilogue(struct bpf_jit *jit)
 197 {
 198         /* Return 0 */
 199         if (jit->seen & SEEN_RET0) {
 200                 jit->ret0_ip = jit->prg;
 201                 /* lghi %r2,0 */
 202                 EMIT4(0xa7290000);
 203         }
 204         jit->exit_ip = jit->prg;
 205         /* Restore registers */
 206         if (jit->seen & SEEN_DATAREF)
 207                 /* lmg %r8,%r15,<offset>(%r15) */
 208                 EMIT6_DISP(0xeb8ff000, 0x0004,
 209                            (jit->seen & SEEN_MEM) ? 200 : 168);
 210         else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL))
 211                 /* lmg %r12,%r13,120(%r15) */
 212                 EMIT6(0xebcdf078, 0x0004);
 213         else if (jit->seen & SEEN_XREG)
 214                 /* lg %r12,120(%r15) */
 215                 EMIT6(0xe3c0f078, 0x0004);
 216         else if (jit->seen & SEEN_LITERAL)
 217                 /* lg %r13,128(%r15) */
 218                 EMIT6(0xe3d0f080, 0x0004);
 219         /* br %r14 */
 220         EMIT2(0x07fe);
 221 }
 222
 223 /*
 224  * make sure we dont leak kernel information to user
 225  */
 226 static void bpf_jit_noleaks(struct bpf_jit *jit, struct sock_filter *filter)
 227 {
 228         /* Clear temporary memory if (seen & SEEN_MEM) */
 229         if (jit->seen & SEEN_MEM)
 230                 /* xc 0(64,%r15),0(%r15) */
 231                 EMIT6(0xd73ff000, 0xf000);
 232         /* Clear X if (seen & SEEN_XREG) */
 233         if (jit->seen & SEEN_XREG)
 234                 /* lhi %r12,0 */
 235                 EMIT4(0xa7c80000);
 236         /* Clear A if the first register does not set it. */
 237         switch (filter[0].code) {
 238         case BPF_S_LD_W_ABS:
 239         case BPF_S_LD_H_ABS:
 240         case BPF_S_LD_B_ABS:
 241         case BPF_S_LD_W_LEN:
 242         case BPF_S_LD_W_IND:
 243         case BPF_S_LD_H_IND:
 244         case BPF_S_LD_B_IND:
 245         case BPF_S_LDX_B_MSH:
 246         case BPF_S_LD_IMM:
 247         case BPF_S_LD_MEM:
 248         case BPF_S_MISC_TXA:
 249         case BPF_S_ANC_PROTOCOL:
 250         case BPF_S_ANC_PKTTYPE:
 251         case BPF_S_ANC_IFINDEX:
 252         case BPF_S_ANC_MARK:
 253         case BPF_S_ANC_QUEUE:
 254         case BPF_S_ANC_HATYPE:
 255         case BPF_S_ANC_RXHASH:
 256         case BPF_S_ANC_CPU:
 257         case BPF_S_RET_K:
 258                 /* first instruction sets A register */
 259                 break;
 260         default: /* A = 0 */
 261                 /* lhi %r5,0 */
 262                 EMIT4(0xa7580000);
 263         }
 264 }
 265
 266 static int bpf_jit_insn(struct bpf_jit *jit, struct sock_filter *filter,
 267                         unsigned int *addrs, int i, int last)
 268 {
 269         unsigned int K;
 270         int offset;
 271         unsigned int mask;
 272
 273         K = filter->k;
 274         switch (filter->code) {
 275         case BPF_S_ALU_ADD_X: /* A += X */
 276                 jit->seen |= SEEN_XREG;
 277                 /* ar %r5,%r12 */
 278                 EMIT2(0x1a5c);
 279                 break;
 280         case BPF_S_ALU_ADD_K: /* A += K */
 281                 if (!K)
 282                         break;
 283                 if (K <= 16383)
 284                         /* ahi %r5,<K> */
 285                         EMIT4_IMM(0xa75a0000, K);
 286                 else if (test_facility(21))
 287                         /* alfi %r5,<K> */
 288                         EMIT6_IMM(0xc25b0000, K);
 289                 else
 290                         /* a %r5,<d(K)>(%r13) */
 291                         EMIT4_DISP(0x5a50d000, EMIT_CONST(K));
 292                 break;
 293         case BPF_S_ALU_SUB_X: /* A -= X */
 294                 jit->seen |= SEEN_XREG;
 295                 /* sr %r5,%r12 */
 296                 EMIT2(0x1b5c);
 297                 break;
 298         case BPF_S_ALU_SUB_K: /* A -= K */
 299                 if (!K)
 300                         break;
 301                 if (K <= 16384)
 302                         /* ahi %r5,-K */
 303                         EMIT4_IMM(0xa75a0000, -K);
 304                 else if (test_facility(21))
 305                         /* alfi %r5,-K */
 306                         EMIT6_IMM(0xc25b0000, -K);
 307                 else
 308                         /* s %r5,<d(K)>(%r13) */
 309                         EMIT4_DISP(0x5b50d000, EMIT_CONST(K));
 310                 break;
 311         case BPF_S_ALU_MUL_X: /* A *= X */
 312                 jit->seen |= SEEN_XREG;
 313                 /* msr %r5,%r12 */
 314                 EMIT4(0xb252005c);
 315                 break;
 316         case BPF_S_ALU_MUL_K: /* A *= K */
 317                 if (K <= 16383)
 318                         /* mhi %r5,K */
 319                         EMIT4_IMM(0xa75c0000, K);
 320                 else if (test_facility(34))
 321                         /* msfi %r5,<K> */
 322                         EMIT6_IMM(0xc2510000, K);
 323                 else
 324                         /* ms %r5,<d(K)>(%r13) */
 325                         EMIT4_DISP(0x7150d000, EMIT_CONST(K));
 326                 break;
 327         case BPF_S_ALU_DIV_X: /* A /= X */
 328                 jit->seen |= SEEN_XREG | SEEN_RET0;
 329                 /* ltr %r12,%r12 */
 330                 EMIT2(0x12cc);
 331                 /* jz <ret0> */
 332                 EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
 333                 /* lhi %r4,0 */
 334                 EMIT4(0xa7480000);
 335                 /* dr %r4,%r12 */
 336                 EMIT2(0x1d4c);
 337                 break;
 338         case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K) */
 339                 /* m %r4,<d(K)>(%r13) */
 340                 EMIT4_DISP(0x5c40d000, EMIT_CONST(K));
 341                 /* lr %r5,%r4 */
 342                 EMIT2(0x1854);
 343                 break;
 344         case BPF_S_ALU_MOD_X: /* A %= X */
 345                 jit->seen |= SEEN_XREG | SEEN_RET0;
 346                 /* ltr %r12,%r12 */
 347                 EMIT2(0x12cc);
 348                 /* jz <ret0> */
 349                 EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
 350                 /* lhi %r4,0 */
 351                 EMIT4(0xa7480000);
 352                 /* dr %r4,%r12 */
 353                 EMIT2(0x1d4c);
 354                 /* lr %r5,%r4 */
 355                 EMIT2(0x1854);
 356                 break;
 357         case BPF_S_ALU_MOD_K: /* A %= K */
 358                 /* lhi %r4,0 */
 359                 EMIT4(0xa7480000);
 360                 /* d %r4,<d(K)>(%r13) */
 361                 EMIT4_DISP(0x5d40d000, EMIT_CONST(K));
 362                 /* lr %r5,%r4 */
 363                 EMIT2(0x1854);
 364                 break;
 365         case BPF_S_ALU_AND_X: /* A &= X */
 366                 jit->seen |= SEEN_XREG;
 367                 /* nr %r5,%r12 */
 368                 EMIT2(0x145c);
 369                 break;
 370         case BPF_S_ALU_AND_K: /* A &= K */
 371                 if (test_facility(21))
 372                         /* nilf %r5,<K> */
 373                         EMIT6_IMM(0xc05b0000, K);
 374                 else
 375                         /* n %r5,<d(K)>(%r13) */
 376                         EMIT4_DISP(0x5450d000, EMIT_CONST(K));
 377                 break;
 378         case BPF_S_ALU_OR_X: /* A |= X */
 379                 jit->seen |= SEEN_XREG;
 380                 /* or %r5,%r12 */
 381                 EMIT2(0x165c);
 382                 break;
 383         case BPF_S_ALU_OR_K: /* A |= K */
 384                 if (test_facility(21))
 385                         /* oilf %r5,<K> */
 386                         EMIT6_IMM(0xc05d0000, K);
 387                 else
 388                         /* o %r5,<d(K)>(%r13) */
 389                         EMIT4_DISP(0x5650d000, EMIT_CONST(K));
 390                 break;
 391         case BPF_S_ANC_ALU_XOR_X: /* A ^= X; */
 392         case BPF_S_ALU_XOR_X:
 393                 jit->seen |= SEEN_XREG;
 394                 /* xr %r5,%r12 */
 395                 EMIT2(0x175c);
 396                 break;
 397         case BPF_S_ALU_XOR_K: /* A ^= K */
 398                 if (!K)
 399                         break;
 400                 /* x %r5,<d(K)>(%r13) */
 401                 EMIT4_DISP(0x5750d000, EMIT_CONST(K));
 402                 break;
 403         case BPF_S_ALU_LSH_X: /* A <<= X; */
 404                 jit->seen |= SEEN_XREG;
 405                 /* sll %r5,0(%r12) */
 406                 EMIT4(0x8950c000);
 407                 break;
 408         case BPF_S_ALU_LSH_K: /* A <<= K */
 409                 if (K == 0)
 410                         break;
 411                 /* sll %r5,K */
 412                 EMIT4_DISP(0x89500000, K);
 413                 break;
 414         case BPF_S_ALU_RSH_X: /* A >>= X; */
 415                 jit->seen |= SEEN_XREG;
 416                 /* srl %r5,0(%r12) */
 417                 EMIT4(0x8850c000);
 418                 break;
 419         case BPF_S_ALU_RSH_K: /* A >>= K; */
 420                 if (K == 0)
 421                         break;
 422                 /* srl %r5,K */
 423                 EMIT4_DISP(0x88500000, K);
 424                 break;
 425         case BPF_S_ALU_NEG: /* A = -A */
 426                 /* lnr %r5,%r5 */
 427                 EMIT2(0x1155);
 428                 break;
 429         case BPF_S_JMP_JA: /* ip += K */
 430                 offset = addrs[i + K] + jit->start - jit->prg;
 431                 EMIT4_PCREL(0xa7f40000, offset);
 432                 break;
 433         case BPF_S_JMP_JGT_K: /* ip += (A > K) ? jt : jf */
 434                 mask = 0x200000; /* jh */
 435                 goto kbranch;
 436         case BPF_S_JMP_JGE_K: /* ip += (A >= K) ? jt : jf */
 437                 mask = 0xa00000; /* jhe */
 438                 goto kbranch;
 439         case BPF_S_JMP_JEQ_K: /* ip += (A == K) ? jt : jf */
 440                 mask = 0x800000; /* je */
 441 kbranch:        /* Emit compare if the branch targets are different */
 442                 if (filter->jt != filter->jf) {
 443                         if (K <= 16383)
 444                                 /* chi %r5,<K> */
 445                                 EMIT4_IMM(0xa75e0000, K);
 446                         else if (test_facility(21))
 447                                 /* clfi %r5,<K> */
 448                                 EMIT6_IMM(0xc25f0000, K);
 449                         else
 450                                 /* c %r5,<d(K)>(%r13) */
 451                                 EMIT4_DISP(0x5950d000, EMIT_CONST(K));
 452                 }
 453 branch:         if (filter->jt == filter->jf) {
 454                         if (filter->jt == 0)
 455                                 break;
 456                         /* j <jt> */
 457                         offset = addrs[i + filter->jt] + jit->start - jit->prg;
 458                         EMIT4_PCREL(0xa7f40000, offset);
 459                         break;
 460                 }
 461                 if (filter->jt != 0) {
 462                         /* brc  <mask>,<jt> */
 463                         offset = addrs[i + filter->jt] + jit->start - jit->prg;
 464                         EMIT4_PCREL(0xa7040000 | mask, offset);
 465                 }
 466                 if (filter->jf != 0) {
 467                         /* brc  <mask^15>,<jf> */
 468                         offset = addrs[i + filter->jf] + jit->start - jit->prg;
 469                         EMIT4_PCREL(0xa7040000 | (mask ^ 0xf00000), offset);
 470                 }
 471                 break;
 472         case BPF_S_JMP_JSET_K: /* ip += (A & K) ? jt : jf */
 473                 mask = 0x700000; /* jnz */
 474                 /* Emit test if the branch targets are different */
 475                 if (filter->jt != filter->jf) {
 476                         if (K > 65535) {
 477                                 /* lr %r4,%r5 */
 478                                 EMIT2(0x1845);
 479                                 /* n %r4,<d(K)>(%r13) */
 480                                 EMIT4_DISP(0x5440d000, EMIT_CONST(K));
 481                         } else
 482                                 /* tmll %r5,K */
 483                                 EMIT4_IMM(0xa7510000, K);
 484                 }
 485                 goto branch;
 486         case BPF_S_JMP_JGT_X: /* ip += (A > X) ? jt : jf */
 487                 mask = 0x200000; /* jh */
 488                 goto xbranch;
 489         case BPF_S_JMP_JGE_X: /* ip += (A >= X) ? jt : jf */
 490                 mask = 0xa00000; /* jhe */
 491                 goto xbranch;
 492         case BPF_S_JMP_JEQ_X: /* ip += (A == X) ? jt : jf */
 493                 mask = 0x800000; /* je */
 494 xbranch:        /* Emit compare if the branch targets are different */
 495                 if (filter->jt != filter->jf) {
 496                         jit->seen |= SEEN_XREG;
 497                         /* cr %r5,%r12 */
 498                         EMIT2(0x195c);
 499                 }
 500                 goto branch;
 501         case BPF_S_JMP_JSET_X: /* ip += (A & X) ? jt : jf */
 502                 mask = 0x700000; /* jnz */
 503                 /* Emit test if the branch targets are different */
 504                 if (filter->jt != filter->jf) {
 505                         jit->seen |= SEEN_XREG;
 506                         /* lr %r4,%r5 */
 507                         EMIT2(0x1845);
 508                         /* nr %r4,%r12 */
 509                         EMIT2(0x144c);
 510                 }
 511                 goto branch;
 512         case BPF_S_LD_W_ABS: /* A = *(u32 *) (skb->data+K) */
 513                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_WORD;
 514                 offset = jit->off_load_word;
 515                 goto load_abs;
 516         case BPF_S_LD_H_ABS: /* A = *(u16 *) (skb->data+K) */
 517                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_HALF;
 518                 offset = jit->off_load_half;
 519                 goto load_abs;
 520         case BPF_S_LD_B_ABS: /* A = *(u8 *) (skb->data+K) */
 521                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_BYTE;
 522                 offset = jit->off_load_byte;
 523 load_abs:       if ((int) K < 0)
 524                         goto out;
 525 call_fn:        /* lg %r1,<d(function)>(%r13) */
 526                 EMIT6_DISP(0xe310d000, 0x0004, offset);
 527                 /* l %r3,<d(K)>(%r13) */
 528                 EMIT4_DISP(0x5830d000, EMIT_CONST(K));
 529                 /* basr %r8,%r1 */
 530                 EMIT2(0x0d81);
 531                 /* jnz <ret0> */
 532                 EMIT4_PCREL(0xa7740000, (jit->ret0_ip - jit->prg));
 533                 break;
 534         case BPF_S_LD_W_IND: /* A = *(u32 *) (skb->data+K+X) */
 535                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IWORD;
 536                 offset = jit->off_load_iword;
 537                 goto call_fn;
 538         case BPF_S_LD_H_IND: /* A = *(u16 *) (skb->data+K+X) */
 539                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IHALF;
 540                 offset = jit->off_load_ihalf;
 541                 goto call_fn;
 542         case BPF_S_LD_B_IND: /* A = *(u8 *) (skb->data+K+X) */
 543                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IBYTE;
 544                 offset = jit->off_load_ibyte;
 545                 goto call_fn;
 546         case BPF_S_LDX_B_MSH:
 547                 /* X = (*(u8 *)(skb->data+K) & 0xf) << 2 */
 548                 jit->seen |= SEEN_RET0;
 549                 if ((int) K < 0) {
 550                         /* j <ret0> */
 551                         EMIT4_PCREL(0xa7f40000, (jit->ret0_ip - jit->prg));
 552                         break;
 553                 }
 554                 jit->seen |= SEEN_DATAREF | SEEN_LOAD_BMSH;
 555                 offset = jit->off_load_bmsh;
 556                 goto call_fn;
 557         case BPF_S_LD_W_LEN: /* A = skb->len; */
 558                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
 559                 /* l %r5,<d(len)>(%r2) */
 560                 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, len));
 561                 break;
 562         case BPF_S_LDX_W_LEN: /* X = skb->len; */
 563                 jit->seen |= SEEN_XREG;
 564                 /* l %r12,<d(len)>(%r2) */
 565                 EMIT4_DISP(0x58c02000, offsetof(struct sk_buff, len));
 566                 break;
 567         case BPF_S_LD_IMM: /* A = K */
 568                 if (K <= 16383)
 569                         /* lhi %r5,K */
 570                         EMIT4_IMM(0xa7580000, K);
 571                 else if (test_facility(21))
 572                         /* llilf %r5,<K> */
 573                         EMIT6_IMM(0xc05f0000, K);
 574                 else
 575                         /* l %r5,<d(K)>(%r13) */
 576                         EMIT4_DISP(0x5850d000, EMIT_CONST(K));
 577                 break;
 578         case BPF_S_LDX_IMM: /* X = K */
 579                 jit->seen |= SEEN_XREG;
 580                 if (K <= 16383)
 581                         /* lhi %r12,<K> */
 582                         EMIT4_IMM(0xa7c80000, K);
 583                 else if (test_facility(21))
 584                         /* llilf %r12,<K> */
 585                         EMIT6_IMM(0xc0cf0000, K);
 586                 else
 587                         /* l %r12,<d(K)>(%r13) */
 588                         EMIT4_DISP(0x58c0d000, EMIT_CONST(K));
 589                 break;
 590         case BPF_S_LD_MEM: /* A = mem[K] */
 591                 jit->seen |= SEEN_MEM;
 592                 /* l %r5,<K>(%r15) */
 593                 EMIT4_DISP(0x5850f000,
 594                            (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
 595                 break;
 596         case BPF_S_LDX_MEM: /* X = mem[K] */
 597                 jit->seen |= SEEN_XREG | SEEN_MEM;
 598                 /* l %r12,<K>(%r15) */
 599                 EMIT4_DISP(0x58c0f000,
 600                            (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
 601                 break;
 602         case BPF_S_MISC_TAX: /* X = A */
 603                 jit->seen |= SEEN_XREG;
 604                 /* lr %r12,%r5 */
 605                 EMIT2(0x18c5);
 606                 break;
 607         case BPF_S_MISC_TXA: /* A = X */
 608                 jit->seen |= SEEN_XREG;
 609                 /* lr %r5,%r12 */
 610                 EMIT2(0x185c);
 611                 break;
 612         case BPF_S_RET_K:
 613                 if (K == 0) {
 614                         jit->seen |= SEEN_RET0;
 615                         if (last)
 616                                 break;
 617                         /* j <ret0> */
 618                         EMIT4_PCREL(0xa7f40000, jit->ret0_ip - jit->prg);
 619                 } else {
 620                         if (K <= 16383)
 621                                 /* lghi %r2,K */
 622                                 EMIT4_IMM(0xa7290000, K);
 623                         else
 624                                 /* llgf %r2,<K>(%r13) */
 625                                 EMIT6_DISP(0xe320d000, 0x0016, EMIT_CONST(K));
 626                         /* j <exit> */
 627                         if (last && !(jit->seen & SEEN_RET0))
 628                                 break;
 629                         EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
 630                 }
 631                 break;
 632         case BPF_S_RET_A:
 633                 /* llgfr %r2,%r5 */
 634                 EMIT4(0xb9160025);
 635                 /* j <exit> */
 636                 EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
 637                 break;
 638         case BPF_S_ST: /* mem[K] = A */
 639                 jit->seen |= SEEN_MEM;
 640                 /* st %r5,<K>(%r15) */
 641                 EMIT4_DISP(0x5050f000,
 642                            (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
 643                 break;
 644         case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
 645                 jit->seen |= SEEN_XREG | SEEN_MEM;
 646                 /* st %r12,<K>(%r15) */
 647                 EMIT4_DISP(0x50c0f000,
 648                            (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
 649                 break;
 650         case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
 651                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
 652                 /* lhi %r5,0 */
 653                 EMIT4(0xa7580000);
 654                 /* icm  %r5,3,<d(protocol)>(%r2) */
 655                 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, protocol));
 656                 break;
 657         case BPF_S_ANC_IFINDEX: /* if (!skb->dev) return 0;
 658                                  * A = skb->dev->ifindex */
 659                 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
 660                 jit->seen |= SEEN_RET0;
 661                 /* lg %r1,<d(dev)>(%r2) */
 662                 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
 663                 /* ltgr %r1,%r1 */
 664                 EMIT4(0xb9020011);
 665                 /* jz <ret0> */
 666                 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
 667                 /* l %r5,<d(ifindex)>(%r1) */
 668                 EMIT4_DISP(0x58501000, offsetof(struct net_device, ifindex));
 669                 break;
 670         case BPF_S_ANC_MARK: /* A = skb->mark */
 671                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
 672                 /* l %r5,<d(mark)>(%r2) */
 673                 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, mark));
 674                 break;
 675         case BPF_S_ANC_QUEUE: /* A = skb->queue_mapping */
 676                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
 677                 /* lhi %r5,0 */
 678                 EMIT4(0xa7580000);
 679                 /* icm  %r5,3,<d(queue_mapping)>(%r2) */
 680                 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, queue_mapping));
 681                 break;
 682         case BPF_S_ANC_HATYPE:  /* if (!skb->dev) return 0;
 683                                  * A = skb->dev->type */
 684                 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
 685                 jit->seen |= SEEN_RET0;
 686                 /* lg %r1,<d(dev)>(%r2) */
 687                 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
 688                 /* ltgr %r1,%r1 */
 689                 EMIT4(0xb9020011);
 690                 /* jz <ret0> */
 691                 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
 692                 /* lhi %r5,0 */
 693                 EMIT4(0xa7580000);
 694                 /* icm  %r5,3,<d(type)>(%r1) */
 695                 EMIT4_DISP(0xbf531000, offsetof(struct net_device, type));
 696                 break;
 697         case BPF_S_ANC_RXHASH: /* A = skb->rxhash */
 698                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4);
 699                 /* l %r5,<d(rxhash)>(%r2) */
 700                 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, rxhash));
 701                 break;
 702         case BPF_S_ANC_CPU: /* A = smp_processor_id() */
 703 #ifdef CONFIG_SMP
 704                 /* l %r5,<d(cpu_nr)> */
 705                 EMIT4_DISP(0x58500000, offsetof(struct _lowcore, cpu_nr));
 706 #else
 707                 /* lhi %r5,0 */
 708                 EMIT4(0xa7580000);
 709 #endif
 710                 break;
 711         default: /* too complex, give up */
 712                 goto out;
 713         }
 714         addrs[i] = jit->prg - jit->start;
 715         return 0;
 716 out:
 717         return -1;
 718 }
 719
 720 void bpf_jit_compile(struct sk_filter *fp)
 721 {
 722         unsigned long size, prg_len, lit_len;
 723         struct bpf_jit jit, cjit;
 724         unsigned int *addrs;
 725         int pass, i;
 726
 727         if (!bpf_jit_enable)
 728                 return;
 729         addrs = kmalloc(fp->len * sizeof(*addrs), GFP_KERNEL);
 730         if (addrs == NULL)
 731                 return;
 732         memset(addrs, 0, fp->len * sizeof(*addrs));
 733         memset(&jit, 0, sizeof(cjit));
 734         memset(&cjit, 0, sizeof(cjit));
 735
 736         for (pass = 0; pass < 10; pass++) {
 737                 jit.prg = jit.start;
 738                 jit.lit = jit.mid;
 739
 740                 bpf_jit_prologue(&jit);
 741                 bpf_jit_noleaks(&jit, fp->insns);
 742                 for (i = 0; i < fp->len; i++) {
 743                         if (bpf_jit_insn(&jit, fp->insns + i, addrs, i,
 744                                          i == fp->len - 1))
 745                                 goto out;
 746                 }
 747                 bpf_jit_epilogue(&jit);
 748                 if (jit.start) {
 749                         WARN_ON(jit.prg > cjit.prg || jit.lit > cjit.lit);
 750                         if (memcmp(&jit, &cjit, sizeof(jit)) == 0)
 751                                 break;
 752                 } else if (jit.prg == cjit.prg && jit.lit == cjit.lit) {
 753                         prg_len = jit.prg - jit.start;
 754                         lit_len = jit.lit - jit.mid;
 755                         size = max_t(unsigned long, prg_len + lit_len,
 756                                      sizeof(struct work_struct));
 757                         if (size >= BPF_SIZE_MAX)
 758                                 goto out;
 759                         jit.start = module_alloc(size);
 760                         if (!jit.start)
 761                                 goto out;
 762                         jit.prg = jit.mid = jit.start + prg_len;
 763                         jit.lit = jit.end = jit.start + prg_len + lit_len;
 764                         jit.base_ip += (unsigned long) jit.start;
 765                         jit.exit_ip += (unsigned long) jit.start;
 766                         jit.ret0_ip += (unsigned long) jit.start;
 767                 }
 768                 cjit = jit;
 769         }
 770         if (bpf_jit_enable > 1) {
 771                 pr_err("flen=%d proglen=%lu pass=%d image=%p\n",
 772                        fp->len, jit.end - jit.start, pass, jit.start);
 773                 if (jit.start) {
 774                         printk(KERN_ERR "JIT code:\n");
 775                         print_fn_code(jit.start, jit.mid - jit.start);
 776                         print_hex_dump(KERN_ERR, "JIT literals:\n",
 777                                        DUMP_PREFIX_ADDRESS, 16, 1,
 778                                        jit.mid, jit.end - jit.mid, false);
 779                 }
 780         }
 781         if (jit.start)
 782                 fp->bpf_func = (void *) jit.start;
 783 out:
 784         kfree(addrs);
 785 }
 786
 787 static void jit_free_defer(struct work_struct *arg)
 788 {
 789         module_free(NULL, arg);
 790 }
 791
 792 /* run from softirq, we must use a work_struct to call
 793  * module_free() from process context
 794  */
 795 void bpf_jit_free(struct sk_filter *fp)
 796 {
 797         struct work_struct *work;
 798
 799         if (fp->bpf_func == sk_run_filter)
 800                 return;
 801         work = (struct work_struct *)fp->bpf_func;
 802         INIT_WORK(work, jit_free_defer);
 803         schedule_work(work);
 804 }