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/if_vlan.h>
  11 #include <linux/filter.h>
  12 #include <asm/cacheflush.h>
  13 #include <asm/processor.h>
  14 #include <asm/facility.h>
  15
  16 /*
  17  * Conventions:
  18  *   %r2 = skb pointer
  19  *   %r3 = offset parameter
  20  *   %r4 = scratch register / length parameter
  21  *   %r5 = BPF A accumulator
  22  *   %r8 = return address
  23  *   %r9 = save register for skb pointer
  24  *   %r10 = skb->data
  25  *   %r11 = skb->len - skb->data_len (headlen)
  26  *   %r12 = BPF X accumulator
  27  *   %r13 = literal pool pointer
  28  *   0(%r15) - 63(%r15) scratch memory array with BPF_MEMWORDS
  29  */
  30 int bpf_jit_enable __read_mostly;
  31
  32 /*
  33  * assembly code in arch/x86/net/bpf_jit.S
  34  */
  35 extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[];
  36 extern u8 sk_load_word_ind[], sk_load_half_ind[], sk_load_byte_ind[];
  37
  38 struct bpf_jit {
  39         unsigned int seen;
  40         u8 *start;
  41         u8 *prg;
  42         u8 *mid;
  43         u8 *lit;
  44         u8 *end;
  45         u8 *base_ip;
  46         u8 *ret0_ip;
  47         u8 *exit_ip;
  48         unsigned int off_load_word;
  49         unsigned int off_load_half;
  50         unsigned int off_load_byte;
  51         unsigned int off_load_bmsh;
  52         unsigned int off_load_iword;
  53         unsigned int off_load_ihalf;
  54         unsigned int off_load_ibyte;
  55 };
  56
  57 #define BPF_SIZE_MAX    4096    /* Max size for program */
  58
  59 #define SEEN_DATAREF    1       /* might call external helpers */
  60 #define SEEN_XREG       2       /* ebx is used */
  61 #define SEEN_MEM        4       /* use mem[] for temporary storage */
  62 #define SEEN_RET0       8       /* pc_ret0 points to a valid return 0 */
  63 #define SEEN_LITERAL    16      /* code uses literals */
  64 #define SEEN_LOAD_WORD  32      /* code uses sk_load_word */
  65 #define SEEN_LOAD_HALF  64      /* code uses sk_load_half */
  66 #define SEEN_LOAD_BYTE  128     /* code uses sk_load_byte */
  67 #define SEEN_LOAD_BMSH  256     /* code uses sk_load_byte_msh */
  68 #define SEEN_LOAD_IWORD 512     /* code uses sk_load_word_ind */
  69 #define SEEN_LOAD_IHALF 1024    /* code uses sk_load_half_ind */
  70 #define SEEN_LOAD_IBYTE 2048    /* code uses sk_load_byte_ind */
  71
  72 #define EMIT2(op)                                       \
  73 ({                                                      \
  74         if (jit->prg + 2 <= jit->mid)                   \
  75                 *(u16 *) jit->prg = op;                 \
  76         jit->prg += 2;                                  \
  77 })
  78
  79 #define EMIT4(op)                                       \
  80 ({                                                      \
  81         if (jit->prg + 4 <= jit->mid)                   \
  82                 *(u32 *) jit->prg = op;                 \
  83         jit->prg += 4;                                  \
  84 })
  85
  86 #define EMIT4_DISP(op, disp)                            \
  87 ({                                                      \
  88         unsigned int __disp = (disp) & 0xfff;           \
  89         EMIT4(op | __disp);                             \
  90 })
  91
  92 #define EMIT4_IMM(op, imm)                              \
  93 ({                                                      \
  94         unsigned int __imm = (imm) & 0xffff;            \
  95         EMIT4(op | __imm);                              \
  96 })
  97
  98 #define EMIT4_PCREL(op, pcrel)                          \
  99 ({                                                      \
 100         long __pcrel = ((pcrel) >> 1) & 0xffff;         \
 101         EMIT4(op | __pcrel);                            \
 102 })
 103
 104 #define EMIT6(op1, op2)                                 \
 105 ({                                                      \
 106         if (jit->prg + 6 <= jit->mid) {                 \
 107                 *(u32 *) jit->prg = op1;                \
 108                 *(u16 *) (jit->prg + 4) = op2;          \
 109         }                                               \
 110         jit->prg += 6;                                  \
 111 })
 112
 113 #define EMIT6_DISP(op1, op2, disp)                      \
 114 ({                                                      \
 115         unsigned int __disp = (disp) & 0xfff;           \
 116         EMIT6(op1 | __disp, op2);                       \
 117 })
 118
 119 #define EMIT6_IMM(op, imm)                              \
 120 ({                                                      \
 121         unsigned int __imm = (imm);                     \
 122         EMIT6(op | (__imm >> 16), __imm & 0xffff);      \
 123 })
 124
 125 #define EMIT_CONST(val)                                 \
 126 ({                                                      \
 127         unsigned int ret;                               \
 128         ret = (unsigned int) (jit->lit - jit->base_ip); \
 129         jit->seen |= SEEN_LITERAL;                      \
 130         if (jit->lit + 4 <= jit->end)                   \
 131                 *(u32 *) jit->lit = val;                \
 132         jit->lit += 4;                                  \
 133         ret;                                            \
 134 })
 135
 136 #define EMIT_FN_CONST(bit, fn)                          \
 137 ({                                                      \
 138         unsigned int ret;                               \
 139         ret = (unsigned int) (jit->lit - jit->base_ip); \
 140         if (jit->seen & bit) {                          \
 141                 jit->seen |= SEEN_LITERAL;              \
 142                 if (jit->lit + 8 <= jit->end)           \
 143                         *(void **) jit->lit = fn;       \
 144                 jit->lit += 8;                          \
 145         }                                               \
 146         ret;                                            \
 147 })
 148
 149 static void bpf_jit_prologue(struct bpf_jit *jit)
 150 {
 151         /* Save registers and create stack frame if necessary */
 152         if (jit->seen & SEEN_DATAREF) {
 153                 /* stmg %r8,%r15,88(%r15) */
 154                 EMIT6(0xeb8ff058, 0x0024);
 155                 /* lgr %r14,%r15 */
 156                 EMIT4(0xb90400ef);
 157                 /* ahi %r15,<offset> */
 158                 EMIT4_IMM(0xa7fa0000, (jit->seen & SEEN_MEM) ? -112 : -80);
 159                 /* stg %r14,152(%r15) */
 160                 EMIT6(0xe3e0f098, 0x0024);
 161         } else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL))
 162                 /* stmg %r12,%r13,120(%r15) */
 163                 EMIT6(0xebcdf078, 0x0024);
 164         else if (jit->seen & SEEN_XREG)
 165                 /* stg %r12,120(%r15) */
 166                 EMIT6(0xe3c0f078, 0x0024);
 167         else if (jit->seen & SEEN_LITERAL)
 168                 /* stg %r13,128(%r15) */
 169                 EMIT6(0xe3d0f080, 0x0024);
 170
 171         /* Setup literal pool */
 172         if (jit->seen & SEEN_LITERAL) {
 173                 /* basr %r13,0 */
 174                 EMIT2(0x0dd0);
 175                 jit->base_ip = jit->prg;
 176         }
 177         jit->off_load_word = EMIT_FN_CONST(SEEN_LOAD_WORD, sk_load_word);
 178         jit->off_load_half = EMIT_FN_CONST(SEEN_LOAD_HALF, sk_load_half);
 179         jit->off_load_byte = EMIT_FN_CONST(SEEN_LOAD_BYTE, sk_load_byte);
 180         jit->off_load_bmsh = EMIT_FN_CONST(SEEN_LOAD_BMSH, sk_load_byte_msh);
 181         jit->off_load_iword = EMIT_FN_CONST(SEEN_LOAD_IWORD, sk_load_word_ind);
 182         jit->off_load_ihalf = EMIT_FN_CONST(SEEN_LOAD_IHALF, sk_load_half_ind);
 183         jit->off_load_ibyte = EMIT_FN_CONST(SEEN_LOAD_IBYTE, sk_load_byte_ind);
 184
 185         /* Filter needs to access skb data */
 186         if (jit->seen & SEEN_DATAREF) {
 187                 /* l %r11,<len>(%r2) */
 188                 EMIT4_DISP(0x58b02000, offsetof(struct sk_buff, len));
 189                 /* s %r11,<data_len>(%r2) */
 190                 EMIT4_DISP(0x5bb02000, offsetof(struct sk_buff, data_len));
 191                 /* lg %r10,<data>(%r2) */
 192                 EMIT6_DISP(0xe3a02000, 0x0004,
 193                            offsetof(struct sk_buff, data));
 194         }
 195 }
 196
 197 static void bpf_jit_epilogue(struct bpf_jit *jit)
 198 {
 199         /* Return 0 */
 200         if (jit->seen & SEEN_RET0) {
 201                 jit->ret0_ip = jit->prg;
 202                 /* lghi %r2,0 */
 203                 EMIT4(0xa7290000);
 204         }
 205         jit->exit_ip = jit->prg;
 206         /* Restore registers */
 207         if (jit->seen & SEEN_DATAREF)
 208                 /* lmg %r8,%r15,<offset>(%r15) */
 209                 EMIT6_DISP(0xeb8ff000, 0x0004,
 210                            (jit->seen & SEEN_MEM) ? 200 : 168);
 211         else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL))
 212                 /* lmg %r12,%r13,120(%r15) */
 213                 EMIT6(0xebcdf078, 0x0004);
 214         else if (jit->seen & SEEN_XREG)
 215                 /* lg %r12,120(%r15) */
 216                 EMIT6(0xe3c0f078, 0x0004);
 217         else if (jit->seen & SEEN_LITERAL)
 218                 /* lg %r13,128(%r15) */
 219                 EMIT6(0xe3d0f080, 0x0004);
 220         /* br %r14 */
 221         EMIT2(0x07fe);
 222 }
 223
 224 /*
 225  * make sure we dont leak kernel information to user
 226  */
 227 static void bpf_jit_noleaks(struct bpf_jit *jit, struct sock_filter *filter)
 228 {
 229         /* Clear temporary memory if (seen & SEEN_MEM) */
 230         if (jit->seen & SEEN_MEM)
 231                 /* xc 0(64,%r15),0(%r15) */
 232                 EMIT6(0xd73ff000, 0xf000);
 233         /* Clear X if (seen & SEEN_XREG) */
 234         if (jit->seen & SEEN_XREG)
 235                 /* lhi %r12,0 */
 236                 EMIT4(0xa7c80000);
 237         /* Clear A if the first register does not set it. */
 238         switch (filter[0].code) {
 239         case BPF_S_LD_W_ABS:
 240         case BPF_S_LD_H_ABS:
 241         case BPF_S_LD_B_ABS:
 242         case BPF_S_LD_W_LEN:
 243         case BPF_S_LD_W_IND:
 244         case BPF_S_LD_H_IND:
 245         case BPF_S_LD_B_IND:
 246         case BPF_S_LDX_B_MSH:
 247         case BPF_S_LD_IMM:
 248         case BPF_S_LD_MEM:
 249         case BPF_S_MISC_TXA:
 250         case BPF_S_ANC_PROTOCOL:
 251         case BPF_S_ANC_PKTTYPE:
 252         case BPF_S_ANC_IFINDEX:
 253         case BPF_S_ANC_MARK:
 254         case BPF_S_ANC_QUEUE:
 255         case BPF_S_ANC_HATYPE:
 256         case BPF_S_ANC_RXHASH:
 257         case BPF_S_ANC_CPU:
 258         case BPF_S_ANC_VLAN_TAG:
 259         case BPF_S_ANC_VLAN_TAG_PRESENT:
 260         case BPF_S_RET_K:
 261                 /* first instruction sets A register */
 262                 break;
 263         default: /* A = 0 */
 264                 /* lhi %r5,0 */
 265                 EMIT4(0xa7580000);
 266         }
 267 }
 268
 269 static int bpf_jit_insn(struct bpf_jit *jit, struct sock_filter *filter,
 270                         unsigned int *addrs, int i, int last)
 271 {
 272         unsigned int K;
 273         int offset;
 274         unsigned int mask;
 275
 276         K = filter->k;
 277         switch (filter->code) {
 278         case BPF_S_ALU_ADD_X: /* A += X */
 279                 jit->seen |= SEEN_XREG;
 280                 /* ar %r5,%r12 */
 281                 EMIT2(0x1a5c);
 282                 break;
 283         case BPF_S_ALU_ADD_K: /* A += K */
 284                 if (!K)
 285                         break;
 286                 if (K <= 16383)
 287                         /* ahi %r5,<K> */
 288                         EMIT4_IMM(0xa75a0000, K);
 289                 else if (test_facility(21))
 290                         /* alfi %r5,<K> */
 291                         EMIT6_IMM(0xc25b0000, K);
 292                 else
 293                         /* a %r5,<d(K)>(%r13) */
 294                         EMIT4_DISP(0x5a50d000, EMIT_CONST(K));
 295                 break;
 296         case BPF_S_ALU_SUB_X: /* A -= X */
 297                 jit->seen |= SEEN_XREG;
 298                 /* sr %r5,%r12 */
 299                 EMIT2(0x1b5c);
 300                 break;
 301         case BPF_S_ALU_SUB_K: /* A -= K */
 302                 if (!K)
 303                         break;
 304                 if (K <= 16384)
 305                         /* ahi %r5,-K */
 306                         EMIT4_IMM(0xa75a0000, -K);
 307                 else if (test_facility(21))
 308                         /* alfi %r5,-K */
 309                         EMIT6_IMM(0xc25b0000, -K);
 310                 else
 311                         /* s %r5,<d(K)>(%r13) */
 312                         EMIT4_DISP(0x5b50d000, EMIT_CONST(K));
 313                 break;
 314         case BPF_S_ALU_MUL_X: /* A *= X */
 315                 jit->seen |= SEEN_XREG;
 316                 /* msr %r5,%r12 */
 317                 EMIT4(0xb252005c);
 318                 break;
 319         case BPF_S_ALU_MUL_K: /* A *= K */
 320                 if (K <= 16383)
 321                         /* mhi %r5,K */
 322                         EMIT4_IMM(0xa75c0000, K);
 323                 else if (test_facility(34))
 324                         /* msfi %r5,<K> */
 325                         EMIT6_IMM(0xc2510000, K);
 326                 else
 327                         /* ms %r5,<d(K)>(%r13) */
 328                         EMIT4_DISP(0x7150d000, EMIT_CONST(K));
 329                 break;
 330         case BPF_S_ALU_DIV_X: /* A /= X */
 331                 jit->seen |= SEEN_XREG | SEEN_RET0;
 332                 /* ltr %r12,%r12 */
 333                 EMIT2(0x12cc);
 334                 /* jz <ret0> */
 335                 EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
 336                 /* lhi %r4,0 */
 337                 EMIT4(0xa7480000);
 338                 /* dr %r4,%r12 */
 339                 EMIT2(0x1d4c);
 340                 break;
 341         case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K) */
 342                 /* m %r4,<d(K)>(%r13) */
 343                 EMIT4_DISP(0x5c40d000, EMIT_CONST(K));
 344                 /* lr %r5,%r4 */
 345                 EMIT2(0x1854);
 346                 break;
 347         case BPF_S_ALU_MOD_X: /* A %= X */
 348                 jit->seen |= SEEN_XREG | SEEN_RET0;
 349                 /* ltr %r12,%r12 */
 350                 EMIT2(0x12cc);
 351                 /* jz <ret0> */
 352                 EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
 353                 /* lhi %r4,0 */
 354                 EMIT4(0xa7480000);
 355                 /* dr %r4,%r12 */
 356                 EMIT2(0x1d4c);
 357                 /* lr %r5,%r4 */
 358                 EMIT2(0x1854);
 359                 break;
 360         case BPF_S_ALU_MOD_K: /* A %= K */
 361                 /* lhi %r4,0 */
 362                 EMIT4(0xa7480000);
 363                 /* d %r4,<d(K)>(%r13) */
 364                 EMIT4_DISP(0x5d40d000, EMIT_CONST(K));
 365                 /* lr %r5,%r4 */
 366                 EMIT2(0x1854);
 367                 break;
 368         case BPF_S_ALU_AND_X: /* A &= X */
 369                 jit->seen |= SEEN_XREG;
 370                 /* nr %r5,%r12 */
 371                 EMIT2(0x145c);
 372                 break;
 373         case BPF_S_ALU_AND_K: /* A &= K */
 374                 if (test_facility(21))
 375                         /* nilf %r5,<K> */
 376                         EMIT6_IMM(0xc05b0000, K);
 377                 else
 378                         /* n %r5,<d(K)>(%r13) */
 379                         EMIT4_DISP(0x5450d000, EMIT_CONST(K));
 380                 break;
 381         case BPF_S_ALU_OR_X: /* A |= X */
 382                 jit->seen |= SEEN_XREG;
 383                 /* or %r5,%r12 */
 384                 EMIT2(0x165c);
 385                 break;
 386         case BPF_S_ALU_OR_K: /* A |= K */
 387                 if (test_facility(21))
 388                         /* oilf %r5,<K> */
 389                         EMIT6_IMM(0xc05d0000, K);
 390                 else
 391                         /* o %r5,<d(K)>(%r13) */
 392                         EMIT4_DISP(0x5650d000, EMIT_CONST(K));
 393                 break;
 394         case BPF_S_ANC_ALU_XOR_X: /* A ^= X; */
 395         case BPF_S_ALU_XOR_X:
 396                 jit->seen |= SEEN_XREG;
 397                 /* xr %r5,%r12 */
 398                 EMIT2(0x175c);
 399                 break;
 400         case BPF_S_ALU_XOR_K: /* A ^= K */
 401                 if (!K)
 402                         break;
 403                 /* x %r5,<d(K)>(%r13) */
 404                 EMIT4_DISP(0x5750d000, EMIT_CONST(K));
 405                 break;
 406         case BPF_S_ALU_LSH_X: /* A <<= X; */
 407                 jit->seen |= SEEN_XREG;
 408                 /* sll %r5,0(%r12) */
 409                 EMIT4(0x8950c000);
 410                 break;
 411         case BPF_S_ALU_LSH_K: /* A <<= K */
 412                 if (K == 0)
 413                         break;
 414                 /* sll %r5,K */
 415                 EMIT4_DISP(0x89500000, K);
 416                 break;
 417         case BPF_S_ALU_RSH_X: /* A >>= X; */
 418                 jit->seen |= SEEN_XREG;
 419                 /* srl %r5,0(%r12) */
 420                 EMIT4(0x8850c000);
 421                 break;
 422         case BPF_S_ALU_RSH_K: /* A >>= K; */
 423                 if (K == 0)
 424                         break;
 425                 /* srl %r5,K */
 426                 EMIT4_DISP(0x88500000, K);
 427                 break;
 428         case BPF_S_ALU_NEG: /* A = -A */
 429                 /* lnr %r5,%r5 */
 430                 EMIT2(0x1155);
 431                 break;
 432         case BPF_S_JMP_JA: /* ip += K */
 433                 offset = addrs[i + K] + jit->start - jit->prg;
 434                 EMIT4_PCREL(0xa7f40000, offset);
 435                 break;
 436         case BPF_S_JMP_JGT_K: /* ip += (A > K) ? jt : jf */
 437                 mask = 0x200000; /* jh */
 438                 goto kbranch;
 439         case BPF_S_JMP_JGE_K: /* ip += (A >= K) ? jt : jf */
 440                 mask = 0xa00000; /* jhe */
 441                 goto kbranch;
 442         case BPF_S_JMP_JEQ_K: /* ip += (A == K) ? jt : jf */
 443                 mask = 0x800000; /* je */
 444 kbranch:        /* Emit compare if the branch targets are different */
 445                 if (filter->jt != filter->jf) {
 446                         if (K <= 16383)
 447                                 /* chi %r5,<K> */
 448                                 EMIT4_IMM(0xa75e0000, K);
 449                         else if (test_facility(21))
 450                                 /* clfi %r5,<K> */
 451                                 EMIT6_IMM(0xc25f0000, K);
 452                         else
 453                                 /* c %r5,<d(K)>(%r13) */
 454                                 EMIT4_DISP(0x5950d000, EMIT_CONST(K));
 455                 }
 456 branch:         if (filter->jt == filter->jf) {
 457                         if (filter->jt == 0)
 458                                 break;
 459                         /* j <jt> */
 460                         offset = addrs[i + filter->jt] + jit->start - jit->prg;
 461                         EMIT4_PCREL(0xa7f40000, offset);
 462                         break;
 463                 }
 464                 if (filter->jt != 0) {
 465                         /* brc  <mask>,<jt> */
 466                         offset = addrs[i + filter->jt] + jit->start - jit->prg;
 467                         EMIT4_PCREL(0xa7040000 | mask, offset);
 468                 }
 469                 if (filter->jf != 0) {
 470                         /* brc  <mask^15>,<jf> */
 471                         offset = addrs[i + filter->jf] + jit->start - jit->prg;
 472                         EMIT4_PCREL(0xa7040000 | (mask ^ 0xf00000), offset);
 473                 }
 474                 break;
 475         case BPF_S_JMP_JSET_K: /* ip += (A & K) ? jt : jf */
 476                 mask = 0x700000; /* jnz */
 477                 /* Emit test if the branch targets are different */
 478                 if (filter->jt != filter->jf) {
 479                         if (K > 65535) {
 480                                 /* lr %r4,%r5 */
 481                                 EMIT2(0x1845);
 482                                 /* n %r4,<d(K)>(%r13) */
 483                                 EMIT4_DISP(0x5440d000, EMIT_CONST(K));
 484                         } else
 485                                 /* tmll %r5,K */
 486                                 EMIT4_IMM(0xa7510000, K);
 487                 }
 488                 goto branch;
 489         case BPF_S_JMP_JGT_X: /* ip += (A > X) ? jt : jf */
 490                 mask = 0x200000; /* jh */
 491                 goto xbranch;
 492         case BPF_S_JMP_JGE_X: /* ip += (A >= X) ? jt : jf */
 493                 mask = 0xa00000; /* jhe */
 494                 goto xbranch;
 495         case BPF_S_JMP_JEQ_X: /* ip += (A == X) ? jt : jf */
 496                 mask = 0x800000; /* je */
 497 xbranch:        /* Emit compare if the branch targets are different */
 498                 if (filter->jt != filter->jf) {
 499                         jit->seen |= SEEN_XREG;
 500                         /* cr %r5,%r12 */
 501                         EMIT2(0x195c);
 502                 }
 503                 goto branch;
 504         case BPF_S_JMP_JSET_X: /* ip += (A & X) ? jt : jf */
 505                 mask = 0x700000; /* jnz */
 506                 /* Emit test if the branch targets are different */
 507                 if (filter->jt != filter->jf) {
 508                         jit->seen |= SEEN_XREG;
 509                         /* lr %r4,%r5 */
 510                         EMIT2(0x1845);
 511                         /* nr %r4,%r12 */
 512                         EMIT2(0x144c);
 513                 }
 514                 goto branch;
 515         case BPF_S_LD_W_ABS: /* A = *(u32 *) (skb->data+K) */
 516                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_WORD;
 517                 offset = jit->off_load_word;
 518                 goto load_abs;
 519         case BPF_S_LD_H_ABS: /* A = *(u16 *) (skb->data+K) */
 520                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_HALF;
 521                 offset = jit->off_load_half;
 522                 goto load_abs;
 523         case BPF_S_LD_B_ABS: /* A = *(u8 *) (skb->data+K) */
 524                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_BYTE;
 525                 offset = jit->off_load_byte;
 526 load_abs:       if ((int) K < 0)
 527                         goto out;
 528 call_fn:        /* lg %r1,<d(function)>(%r13) */
 529                 EMIT6_DISP(0xe310d000, 0x0004, offset);
 530                 /* l %r3,<d(K)>(%r13) */
 531                 EMIT4_DISP(0x5830d000, EMIT_CONST(K));
 532                 /* basr %r8,%r1 */
 533                 EMIT2(0x0d81);
 534                 /* jnz <ret0> */
 535                 EMIT4_PCREL(0xa7740000, (jit->ret0_ip - jit->prg));
 536                 break;
 537         case BPF_S_LD_W_IND: /* A = *(u32 *) (skb->data+K+X) */
 538                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IWORD;
 539                 offset = jit->off_load_iword;
 540                 goto call_fn;
 541         case BPF_S_LD_H_IND: /* A = *(u16 *) (skb->data+K+X) */
 542                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IHALF;
 543                 offset = jit->off_load_ihalf;
 544                 goto call_fn;
 545         case BPF_S_LD_B_IND: /* A = *(u8 *) (skb->data+K+X) */
 546                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IBYTE;
 547                 offset = jit->off_load_ibyte;
 548                 goto call_fn;
 549         case BPF_S_LDX_B_MSH:
 550                 /* X = (*(u8 *)(skb->data+K) & 0xf) << 2 */
 551                 jit->seen |= SEEN_RET0;
 552                 if ((int) K < 0) {
 553                         /* j <ret0> */
 554                         EMIT4_PCREL(0xa7f40000, (jit->ret0_ip - jit->prg));
 555                         break;
 556                 }
 557                 jit->seen |= SEEN_DATAREF | SEEN_LOAD_BMSH;
 558                 offset = jit->off_load_bmsh;
 559                 goto call_fn;
 560         case BPF_S_LD_W_LEN: /* A = skb->len; */
 561                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
 562                 /* l %r5,<d(len)>(%r2) */
 563                 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, len));
 564                 break;
 565         case BPF_S_LDX_W_LEN: /* X = skb->len; */
 566                 jit->seen |= SEEN_XREG;
 567                 /* l %r12,<d(len)>(%r2) */
 568                 EMIT4_DISP(0x58c02000, offsetof(struct sk_buff, len));
 569                 break;
 570         case BPF_S_LD_IMM: /* A = K */
 571                 if (K <= 16383)
 572                         /* lhi %r5,K */
 573                         EMIT4_IMM(0xa7580000, K);
 574                 else if (test_facility(21))
 575                         /* llilf %r5,<K> */
 576                         EMIT6_IMM(0xc05f0000, K);
 577                 else
 578                         /* l %r5,<d(K)>(%r13) */
 579                         EMIT4_DISP(0x5850d000, EMIT_CONST(K));
 580                 break;
 581         case BPF_S_LDX_IMM: /* X = K */
 582                 jit->seen |= SEEN_XREG;
 583                 if (K <= 16383)
 584                         /* lhi %r12,<K> */
 585                         EMIT4_IMM(0xa7c80000, K);
 586                 else if (test_facility(21))
 587                         /* llilf %r12,<K> */
 588                         EMIT6_IMM(0xc0cf0000, K);
 589                 else
 590                         /* l %r12,<d(K)>(%r13) */
 591                         EMIT4_DISP(0x58c0d000, EMIT_CONST(K));
 592                 break;
 593         case BPF_S_LD_MEM: /* A = mem[K] */
 594                 jit->seen |= SEEN_MEM;
 595                 /* l %r5,<K>(%r15) */
 596                 EMIT4_DISP(0x5850f000,
 597                            (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
 598                 break;
 599         case BPF_S_LDX_MEM: /* X = mem[K] */
 600                 jit->seen |= SEEN_XREG | SEEN_MEM;
 601                 /* l %r12,<K>(%r15) */
 602                 EMIT4_DISP(0x58c0f000,
 603                            (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
 604                 break;
 605         case BPF_S_MISC_TAX: /* X = A */
 606                 jit->seen |= SEEN_XREG;
 607                 /* lr %r12,%r5 */
 608                 EMIT2(0x18c5);
 609                 break;
 610         case BPF_S_MISC_TXA: /* A = X */
 611                 jit->seen |= SEEN_XREG;
 612                 /* lr %r5,%r12 */
 613                 EMIT2(0x185c);
 614                 break;
 615         case BPF_S_RET_K:
 616                 if (K == 0) {
 617                         jit->seen |= SEEN_RET0;
 618                         if (last)
 619                                 break;
 620                         /* j <ret0> */
 621                         EMIT4_PCREL(0xa7f40000, jit->ret0_ip - jit->prg);
 622                 } else {
 623                         if (K <= 16383)
 624                                 /* lghi %r2,K */
 625                                 EMIT4_IMM(0xa7290000, K);
 626                         else
 627                                 /* llgf %r2,<K>(%r13) */
 628                                 EMIT6_DISP(0xe320d000, 0x0016, EMIT_CONST(K));
 629                         /* j <exit> */
 630                         if (last && !(jit->seen & SEEN_RET0))
 631                                 break;
 632                         EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
 633                 }
 634                 break;
 635         case BPF_S_RET_A:
 636                 /* llgfr %r2,%r5 */
 637                 EMIT4(0xb9160025);
 638                 /* j <exit> */
 639                 EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
 640                 break;
 641         case BPF_S_ST: /* mem[K] = A */
 642                 jit->seen |= SEEN_MEM;
 643                 /* st %r5,<K>(%r15) */
 644                 EMIT4_DISP(0x5050f000,
 645                            (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
 646                 break;
 647         case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
 648                 jit->seen |= SEEN_XREG | SEEN_MEM;
 649                 /* st %r12,<K>(%r15) */
 650                 EMIT4_DISP(0x50c0f000,
 651                            (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
 652                 break;
 653         case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
 654                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
 655                 /* lhi %r5,0 */
 656                 EMIT4(0xa7580000);
 657                 /* icm  %r5,3,<d(protocol)>(%r2) */
 658                 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, protocol));
 659                 break;
 660         case BPF_S_ANC_IFINDEX: /* if (!skb->dev) return 0;
 661                                  * A = skb->dev->ifindex */
 662                 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
 663                 jit->seen |= SEEN_RET0;
 664                 /* lg %r1,<d(dev)>(%r2) */
 665                 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
 666                 /* ltgr %r1,%r1 */
 667                 EMIT4(0xb9020011);
 668                 /* jz <ret0> */
 669                 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
 670                 /* l %r5,<d(ifindex)>(%r1) */
 671                 EMIT4_DISP(0x58501000, offsetof(struct net_device, ifindex));
 672                 break;
 673         case BPF_S_ANC_MARK: /* A = skb->mark */
 674                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
 675                 /* l %r5,<d(mark)>(%r2) */
 676                 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, mark));
 677                 break;
 678         case BPF_S_ANC_QUEUE: /* A = skb->queue_mapping */
 679                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
 680                 /* lhi %r5,0 */
 681                 EMIT4(0xa7580000);
 682                 /* icm  %r5,3,<d(queue_mapping)>(%r2) */
 683                 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, queue_mapping));
 684                 break;
 685         case BPF_S_ANC_HATYPE:  /* if (!skb->dev) return 0;
 686                                  * A = skb->dev->type */
 687                 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
 688                 jit->seen |= SEEN_RET0;
 689                 /* lg %r1,<d(dev)>(%r2) */
 690                 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
 691                 /* ltgr %r1,%r1 */
 692                 EMIT4(0xb9020011);
 693                 /* jz <ret0> */
 694                 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
 695                 /* lhi %r5,0 */
 696                 EMIT4(0xa7580000);
 697                 /* icm  %r5,3,<d(type)>(%r1) */
 698                 EMIT4_DISP(0xbf531000, offsetof(struct net_device, type));
 699                 break;
 700         case BPF_S_ANC_RXHASH: /* A = skb->rxhash */
 701                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4);
 702                 /* l %r5,<d(rxhash)>(%r2) */
 703                 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, rxhash));
 704                 break;
 705         case BPF_S_ANC_VLAN_TAG:
 706         case BPF_S_ANC_VLAN_TAG_PRESENT:
 707                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
 708                 BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
 709                 /* lhi %r5,0 */
 710                 EMIT4(0xa7580000);
 711                 /* icm  %r5,3,<d(vlan_tci)>(%r2) */
 712                 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, vlan_tci));
 713                 if (filter->code == BPF_S_ANC_VLAN_TAG) {
 714                         /* nill %r5,0xefff */
 715                         EMIT4_IMM(0xa5570000, ~VLAN_TAG_PRESENT);
 716                 } else {
 717                         /* nill %r5,0x1000 */
 718                         EMIT4_IMM(0xa5570000, VLAN_TAG_PRESENT);
 719                         /* srl %r5,12 */
 720                         EMIT4_DISP(0x88500000, 12);
 721                 }
 722                 break;
 723         case BPF_S_ANC_CPU: /* A = smp_processor_id() */
 724 #ifdef CONFIG_SMP
 725                 /* l %r5,<d(cpu_nr)> */
 726                 EMIT4_DISP(0x58500000, offsetof(struct _lowcore, cpu_nr));
 727 #else
 728                 /* lhi %r5,0 */
 729                 EMIT4(0xa7580000);
 730 #endif
 731                 break;
 732         default: /* too complex, give up */
 733                 goto out;
 734         }
 735         addrs[i] = jit->prg - jit->start;
 736         return 0;
 737 out:
 738         return -1;
 739 }
 740
 741 void bpf_jit_compile(struct sk_filter *fp)
 742 {
 743         unsigned long size, prg_len, lit_len;
 744         struct bpf_jit jit, cjit;
 745         unsigned int *addrs;
 746         int pass, i;
 747
 748         if (!bpf_jit_enable)
 749                 return;
 750         addrs = kcalloc(fp->len, sizeof(*addrs), GFP_KERNEL);
 751         if (addrs == NULL)
 752                 return;
 753         memset(&jit, 0, sizeof(cjit));
 754         memset(&cjit, 0, sizeof(cjit));
 755
 756         for (pass = 0; pass < 10; pass++) {
 757                 jit.prg = jit.start;
 758                 jit.lit = jit.mid;
 759
 760                 bpf_jit_prologue(&jit);
 761                 bpf_jit_noleaks(&jit, fp->insns);
 762                 for (i = 0; i < fp->len; i++) {
 763                         if (bpf_jit_insn(&jit, fp->insns + i, addrs, i,
 764                                          i == fp->len - 1))
 765                                 goto out;
 766                 }
 767                 bpf_jit_epilogue(&jit);
 768                 if (jit.start) {
 769                         WARN_ON(jit.prg > cjit.prg || jit.lit > cjit.lit);
 770                         if (memcmp(&jit, &cjit, sizeof(jit)) == 0)
 771                                 break;
 772                 } else if (jit.prg == cjit.prg && jit.lit == cjit.lit) {
 773                         prg_len = jit.prg - jit.start;
 774                         lit_len = jit.lit - jit.mid;
 775                         size = prg_len + lit_len;
 776                         if (size >= BPF_SIZE_MAX)
 777                                 goto out;
 778                         jit.start = module_alloc(size);
 779                         if (!jit.start)
 780                                 goto out;
 781                         jit.prg = jit.mid = jit.start + prg_len;
 782                         jit.lit = jit.end = jit.start + prg_len + lit_len;
 783                         jit.base_ip += (unsigned long) jit.start;
 784                         jit.exit_ip += (unsigned long) jit.start;
 785                         jit.ret0_ip += (unsigned long) jit.start;
 786                 }
 787                 cjit = jit;
 788         }
 789         if (bpf_jit_enable > 1) {
 790                 bpf_jit_dump(fp->len, jit.end - jit.start, pass, jit.start);
 791                 if (jit.start)
 792                         print_fn_code(jit.start, jit.mid - jit.start);
 793         }
 794         if (jit.start)
 795                 fp->bpf_func = (void *) jit.start;
 796 out:
 797         kfree(addrs);
 798 }
 799
 800 void bpf_jit_free(struct sk_filter *fp)
 801 {
 802         if (fp->bpf_func != sk_run_filter)
 803                 module_free(NULL, fp->bpf_func);
 804 }