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_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_ANC_VLAN_TAG:
 258         case BPF_S_ANC_VLAN_TAG_PRESENT:
 259         case BPF_S_RET_K:
 260                 /* first instruction sets A register */
 261                 break;
 262         default: /* A = 0 */
 263                 /* lhi %r5,0 */
 264                 EMIT4(0xa7580000);
 265         }
 266 }
 267
 268 static int bpf_jit_insn(struct bpf_jit *jit, struct sock_filter *filter,
 269                         unsigned int *addrs, int i, int last)
 270 {
 271         unsigned int K;
 272         int offset;
 273         unsigned int mask;
 274
 275         K = filter->k;
 276         switch (filter->code) {
 277         case BPF_S_ALU_ADD_X: /* A += X */
 278                 jit->seen |= SEEN_XREG;
 279                 /* ar %r5,%r12 */
 280                 EMIT2(0x1a5c);
 281                 break;
 282         case BPF_S_ALU_ADD_K: /* A += K */
 283                 if (!K)
 284                         break;
 285                 if (K <= 16383)
 286                         /* ahi %r5,<K> */
 287                         EMIT4_IMM(0xa75a0000, K);
 288                 else if (test_facility(21))
 289                         /* alfi %r5,<K> */
 290                         EMIT6_IMM(0xc25b0000, K);
 291                 else
 292                         /* a %r5,<d(K)>(%r13) */
 293                         EMIT4_DISP(0x5a50d000, EMIT_CONST(K));
 294                 break;
 295         case BPF_S_ALU_SUB_X: /* A -= X */
 296                 jit->seen |= SEEN_XREG;
 297                 /* sr %r5,%r12 */
 298                 EMIT2(0x1b5c);
 299                 break;
 300         case BPF_S_ALU_SUB_K: /* A -= K */
 301                 if (!K)
 302                         break;
 303                 if (K <= 16384)
 304                         /* ahi %r5,-K */
 305                         EMIT4_IMM(0xa75a0000, -K);
 306                 else if (test_facility(21))
 307                         /* alfi %r5,-K */
 308                         EMIT6_IMM(0xc25b0000, -K);
 309                 else
 310                         /* s %r5,<d(K)>(%r13) */
 311                         EMIT4_DISP(0x5b50d000, EMIT_CONST(K));
 312                 break;
 313         case BPF_S_ALU_MUL_X: /* A *= X */
 314                 jit->seen |= SEEN_XREG;
 315                 /* msr %r5,%r12 */
 316                 EMIT4(0xb252005c);
 317                 break;
 318         case BPF_S_ALU_MUL_K: /* A *= K */
 319                 if (K <= 16383)
 320                         /* mhi %r5,K */
 321                         EMIT4_IMM(0xa75c0000, K);
 322                 else if (test_facility(34))
 323                         /* msfi %r5,<K> */
 324                         EMIT6_IMM(0xc2510000, K);
 325                 else
 326                         /* ms %r5,<d(K)>(%r13) */
 327                         EMIT4_DISP(0x7150d000, EMIT_CONST(K));
 328                 break;
 329         case BPF_S_ALU_DIV_X: /* A /= X */
 330                 jit->seen |= SEEN_XREG | SEEN_RET0;
 331                 /* ltr %r12,%r12 */
 332                 EMIT2(0x12cc);
 333                 /* jz <ret0> */
 334                 EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
 335                 /* lhi %r4,0 */
 336                 EMIT4(0xa7480000);
 337                 /* dlr %r4,%r12 */
 338                 EMIT4(0xb997004c);
 339                 break;
 340         case BPF_S_ALU_DIV_K: /* A /= K */
 341                 if (K == 1)
 342                         break;
 343                 /* lhi %r4,0 */
 344                 EMIT4(0xa7480000);
 345                 /* dl %r4,<d(K)>(%r13) */
 346                 EMIT6_DISP(0xe340d000, 0x0097, EMIT_CONST(K));
 347                 break;
 348         case BPF_S_ALU_MOD_X: /* A %= X */
 349                 jit->seen |= SEEN_XREG | SEEN_RET0;
 350                 /* ltr %r12,%r12 */
 351                 EMIT2(0x12cc);
 352                 /* jz <ret0> */
 353                 EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
 354                 /* lhi %r4,0 */
 355                 EMIT4(0xa7480000);
 356                 /* dlr %r4,%r12 */
 357                 EMIT4(0xb997004c);
 358                 /* lr %r5,%r4 */
 359                 EMIT2(0x1854);
 360                 break;
 361         case BPF_S_ALU_MOD_K: /* A %= K */
 362                 if (K == 1) {
 363                         /* lhi %r5,0 */
 364                         EMIT4(0xa7580000);
 365                         break;
 366                 }
 367                 /* lhi %r4,0 */
 368                 EMIT4(0xa7480000);
 369                 /* dl %r4,<d(K)>(%r13) */
 370                 EMIT6_DISP(0xe340d000, 0x0097, EMIT_CONST(K));
 371                 /* lr %r5,%r4 */
 372                 EMIT2(0x1854);
 373                 break;
 374         case BPF_S_ALU_AND_X: /* A &= X */
 375                 jit->seen |= SEEN_XREG;
 376                 /* nr %r5,%r12 */
 377                 EMIT2(0x145c);
 378                 break;
 379         case BPF_S_ALU_AND_K: /* A &= K */
 380                 if (test_facility(21))
 381                         /* nilf %r5,<K> */
 382                         EMIT6_IMM(0xc05b0000, K);
 383                 else
 384                         /* n %r5,<d(K)>(%r13) */
 385                         EMIT4_DISP(0x5450d000, EMIT_CONST(K));
 386                 break;
 387         case BPF_S_ALU_OR_X: /* A |= X */
 388                 jit->seen |= SEEN_XREG;
 389                 /* or %r5,%r12 */
 390                 EMIT2(0x165c);
 391                 break;
 392         case BPF_S_ALU_OR_K: /* A |= K */
 393                 if (test_facility(21))
 394                         /* oilf %r5,<K> */
 395                         EMIT6_IMM(0xc05d0000, K);
 396                 else
 397                         /* o %r5,<d(K)>(%r13) */
 398                         EMIT4_DISP(0x5650d000, EMIT_CONST(K));
 399                 break;
 400         case BPF_S_ANC_ALU_XOR_X: /* A ^= X; */
 401         case BPF_S_ALU_XOR_X:
 402                 jit->seen |= SEEN_XREG;
 403                 /* xr %r5,%r12 */
 404                 EMIT2(0x175c);
 405                 break;
 406         case BPF_S_ALU_XOR_K: /* A ^= K */
 407                 if (!K)
 408                         break;
 409                 /* x %r5,<d(K)>(%r13) */
 410                 EMIT4_DISP(0x5750d000, EMIT_CONST(K));
 411                 break;
 412         case BPF_S_ALU_LSH_X: /* A <<= X; */
 413                 jit->seen |= SEEN_XREG;
 414                 /* sll %r5,0(%r12) */
 415                 EMIT4(0x8950c000);
 416                 break;
 417         case BPF_S_ALU_LSH_K: /* A <<= K */
 418                 if (K == 0)
 419                         break;
 420                 /* sll %r5,K */
 421                 EMIT4_DISP(0x89500000, K);
 422                 break;
 423         case BPF_S_ALU_RSH_X: /* A >>= X; */
 424                 jit->seen |= SEEN_XREG;
 425                 /* srl %r5,0(%r12) */
 426                 EMIT4(0x8850c000);
 427                 break;
 428         case BPF_S_ALU_RSH_K: /* A >>= K; */
 429                 if (K == 0)
 430                         break;
 431                 /* srl %r5,K */
 432                 EMIT4_DISP(0x88500000, K);
 433                 break;
 434         case BPF_S_ALU_NEG: /* A = -A */
 435                 /* lnr %r5,%r5 */
 436                 EMIT2(0x1155);
 437                 break;
 438         case BPF_S_JMP_JA: /* ip += K */
 439                 offset = addrs[i + K] + jit->start - jit->prg;
 440                 EMIT4_PCREL(0xa7f40000, offset);
 441                 break;
 442         case BPF_S_JMP_JGT_K: /* ip += (A > K) ? jt : jf */
 443                 mask = 0x200000; /* jh */
 444                 goto kbranch;
 445         case BPF_S_JMP_JGE_K: /* ip += (A >= K) ? jt : jf */
 446                 mask = 0xa00000; /* jhe */
 447                 goto kbranch;
 448         case BPF_S_JMP_JEQ_K: /* ip += (A == K) ? jt : jf */
 449                 mask = 0x800000; /* je */
 450 kbranch:        /* Emit compare if the branch targets are different */
 451                 if (filter->jt != filter->jf) {
 452                         if (K <= 16383)
 453                                 /* chi %r5,<K> */
 454                                 EMIT4_IMM(0xa75e0000, K);
 455                         else if (test_facility(21))
 456                                 /* clfi %r5,<K> */
 457                                 EMIT6_IMM(0xc25f0000, K);
 458                         else
 459                                 /* c %r5,<d(K)>(%r13) */
 460                                 EMIT4_DISP(0x5950d000, EMIT_CONST(K));
 461                 }
 462 branch:         if (filter->jt == filter->jf) {
 463                         if (filter->jt == 0)
 464                                 break;
 465                         /* j <jt> */
 466                         offset = addrs[i + filter->jt] + jit->start - jit->prg;
 467                         EMIT4_PCREL(0xa7f40000, offset);
 468                         break;
 469                 }
 470                 if (filter->jt != 0) {
 471                         /* brc  <mask>,<jt> */
 472                         offset = addrs[i + filter->jt] + jit->start - jit->prg;
 473                         EMIT4_PCREL(0xa7040000 | mask, offset);
 474                 }
 475                 if (filter->jf != 0) {
 476                         /* brc  <mask^15>,<jf> */
 477                         offset = addrs[i + filter->jf] + jit->start - jit->prg;
 478                         EMIT4_PCREL(0xa7040000 | (mask ^ 0xf00000), offset);
 479                 }
 480                 break;
 481         case BPF_S_JMP_JSET_K: /* ip += (A & K) ? jt : jf */
 482                 mask = 0x700000; /* jnz */
 483                 /* Emit test if the branch targets are different */
 484                 if (filter->jt != filter->jf) {
 485                         if (K > 65535) {
 486                                 /* lr %r4,%r5 */
 487                                 EMIT2(0x1845);
 488                                 /* n %r4,<d(K)>(%r13) */
 489                                 EMIT4_DISP(0x5440d000, EMIT_CONST(K));
 490                         } else
 491                                 /* tmll %r5,K */
 492                                 EMIT4_IMM(0xa7510000, K);
 493                 }
 494                 goto branch;
 495         case BPF_S_JMP_JGT_X: /* ip += (A > X) ? jt : jf */
 496                 mask = 0x200000; /* jh */
 497                 goto xbranch;
 498         case BPF_S_JMP_JGE_X: /* ip += (A >= X) ? jt : jf */
 499                 mask = 0xa00000; /* jhe */
 500                 goto xbranch;
 501         case BPF_S_JMP_JEQ_X: /* ip += (A == X) ? jt : jf */
 502                 mask = 0x800000; /* je */
 503 xbranch:        /* Emit compare if the branch targets are different */
 504                 if (filter->jt != filter->jf) {
 505                         jit->seen |= SEEN_XREG;
 506                         /* cr %r5,%r12 */
 507                         EMIT2(0x195c);
 508                 }
 509                 goto branch;
 510         case BPF_S_JMP_JSET_X: /* ip += (A & X) ? jt : jf */
 511                 mask = 0x700000; /* jnz */
 512                 /* Emit test if the branch targets are different */
 513                 if (filter->jt != filter->jf) {
 514                         jit->seen |= SEEN_XREG;
 515                         /* lr %r4,%r5 */
 516                         EMIT2(0x1845);
 517                         /* nr %r4,%r12 */
 518                         EMIT2(0x144c);
 519                 }
 520                 goto branch;
 521         case BPF_S_LD_W_ABS: /* A = *(u32 *) (skb->data+K) */
 522                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_WORD;
 523                 offset = jit->off_load_word;
 524                 goto load_abs;
 525         case BPF_S_LD_H_ABS: /* A = *(u16 *) (skb->data+K) */
 526                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_HALF;
 527                 offset = jit->off_load_half;
 528                 goto load_abs;
 529         case BPF_S_LD_B_ABS: /* A = *(u8 *) (skb->data+K) */
 530                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_BYTE;
 531                 offset = jit->off_load_byte;
 532 load_abs:       if ((int) K < 0)
 533                         goto out;
 534 call_fn:        /* lg %r1,<d(function)>(%r13) */
 535                 EMIT6_DISP(0xe310d000, 0x0004, offset);
 536                 /* l %r3,<d(K)>(%r13) */
 537                 EMIT4_DISP(0x5830d000, EMIT_CONST(K));
 538                 /* basr %r8,%r1 */
 539                 EMIT2(0x0d81);
 540                 /* jnz <ret0> */
 541                 EMIT4_PCREL(0xa7740000, (jit->ret0_ip - jit->prg));
 542                 break;
 543         case BPF_S_LD_W_IND: /* A = *(u32 *) (skb->data+K+X) */
 544                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IWORD;
 545                 offset = jit->off_load_iword;
 546                 goto call_fn;
 547         case BPF_S_LD_H_IND: /* A = *(u16 *) (skb->data+K+X) */
 548                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IHALF;
 549                 offset = jit->off_load_ihalf;
 550                 goto call_fn;
 551         case BPF_S_LD_B_IND: /* A = *(u8 *) (skb->data+K+X) */
 552                 jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IBYTE;
 553                 offset = jit->off_load_ibyte;
 554                 goto call_fn;
 555         case BPF_S_LDX_B_MSH:
 556                 /* X = (*(u8 *)(skb->data+K) & 0xf) << 2 */
 557                 jit->seen |= SEEN_RET0;
 558                 if ((int) K < 0) {
 559                         /* j <ret0> */
 560                         EMIT4_PCREL(0xa7f40000, (jit->ret0_ip - jit->prg));
 561                         break;
 562                 }
 563                 jit->seen |= SEEN_DATAREF | SEEN_LOAD_BMSH;
 564                 offset = jit->off_load_bmsh;
 565                 goto call_fn;
 566         case BPF_S_LD_W_LEN: /* A = skb->len; */
 567                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
 568                 /* l %r5,<d(len)>(%r2) */
 569                 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, len));
 570                 break;
 571         case BPF_S_LDX_W_LEN: /* X = skb->len; */
 572                 jit->seen |= SEEN_XREG;
 573                 /* l %r12,<d(len)>(%r2) */
 574                 EMIT4_DISP(0x58c02000, offsetof(struct sk_buff, len));
 575                 break;
 576         case BPF_S_LD_IMM: /* A = K */
 577                 if (K <= 16383)
 578                         /* lhi %r5,K */
 579                         EMIT4_IMM(0xa7580000, K);
 580                 else if (test_facility(21))
 581                         /* llilf %r5,<K> */
 582                         EMIT6_IMM(0xc05f0000, K);
 583                 else
 584                         /* l %r5,<d(K)>(%r13) */
 585                         EMIT4_DISP(0x5850d000, EMIT_CONST(K));
 586                 break;
 587         case BPF_S_LDX_IMM: /* X = K */
 588                 jit->seen |= SEEN_XREG;
 589                 if (K <= 16383)
 590                         /* lhi %r12,<K> */
 591                         EMIT4_IMM(0xa7c80000, K);
 592                 else if (test_facility(21))
 593                         /* llilf %r12,<K> */
 594                         EMIT6_IMM(0xc0cf0000, K);
 595                 else
 596                         /* l %r12,<d(K)>(%r13) */
 597                         EMIT4_DISP(0x58c0d000, EMIT_CONST(K));
 598                 break;
 599         case BPF_S_LD_MEM: /* A = mem[K] */
 600                 jit->seen |= SEEN_MEM;
 601                 /* l %r5,<K>(%r15) */
 602                 EMIT4_DISP(0x5850f000,
 603                            (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
 604                 break;
 605         case BPF_S_LDX_MEM: /* X = mem[K] */
 606                 jit->seen |= SEEN_XREG | SEEN_MEM;
 607                 /* l %r12,<K>(%r15) */
 608                 EMIT4_DISP(0x58c0f000,
 609                            (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
 610                 break;
 611         case BPF_S_MISC_TAX: /* X = A */
 612                 jit->seen |= SEEN_XREG;
 613                 /* lr %r12,%r5 */
 614                 EMIT2(0x18c5);
 615                 break;
 616         case BPF_S_MISC_TXA: /* A = X */
 617                 jit->seen |= SEEN_XREG;
 618                 /* lr %r5,%r12 */
 619                 EMIT2(0x185c);
 620                 break;
 621         case BPF_S_RET_K:
 622                 if (K == 0) {
 623                         jit->seen |= SEEN_RET0;
 624                         if (last)
 625                                 break;
 626                         /* j <ret0> */
 627                         EMIT4_PCREL(0xa7f40000, jit->ret0_ip - jit->prg);
 628                 } else {
 629                         if (K <= 16383)
 630                                 /* lghi %r2,K */
 631                                 EMIT4_IMM(0xa7290000, K);
 632                         else
 633                                 /* llgf %r2,<K>(%r13) */
 634                                 EMIT6_DISP(0xe320d000, 0x0016, EMIT_CONST(K));
 635                         /* j <exit> */
 636                         if (last && !(jit->seen & SEEN_RET0))
 637                                 break;
 638                         EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
 639                 }
 640                 break;
 641         case BPF_S_RET_A:
 642                 /* llgfr %r2,%r5 */
 643                 EMIT4(0xb9160025);
 644                 /* j <exit> */
 645                 EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
 646                 break;
 647         case BPF_S_ST: /* mem[K] = A */
 648                 jit->seen |= SEEN_MEM;
 649                 /* st %r5,<K>(%r15) */
 650                 EMIT4_DISP(0x5050f000,
 651                            (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
 652                 break;
 653         case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
 654                 jit->seen |= SEEN_XREG | SEEN_MEM;
 655                 /* st %r12,<K>(%r15) */
 656                 EMIT4_DISP(0x50c0f000,
 657                            (jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
 658                 break;
 659         case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
 660                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
 661                 /* lhi %r5,0 */
 662                 EMIT4(0xa7580000);
 663                 /* icm  %r5,3,<d(protocol)>(%r2) */
 664                 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, protocol));
 665                 break;
 666         case BPF_S_ANC_IFINDEX: /* if (!skb->dev) return 0;
 667                                  * A = skb->dev->ifindex */
 668                 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
 669                 jit->seen |= SEEN_RET0;
 670                 /* lg %r1,<d(dev)>(%r2) */
 671                 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
 672                 /* ltgr %r1,%r1 */
 673                 EMIT4(0xb9020011);
 674                 /* jz <ret0> */
 675                 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
 676                 /* l %r5,<d(ifindex)>(%r1) */
 677                 EMIT4_DISP(0x58501000, offsetof(struct net_device, ifindex));
 678                 break;
 679         case BPF_S_ANC_MARK: /* A = skb->mark */
 680                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
 681                 /* l %r5,<d(mark)>(%r2) */
 682                 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, mark));
 683                 break;
 684         case BPF_S_ANC_QUEUE: /* A = skb->queue_mapping */
 685                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
 686                 /* lhi %r5,0 */
 687                 EMIT4(0xa7580000);
 688                 /* icm  %r5,3,<d(queue_mapping)>(%r2) */
 689                 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, queue_mapping));
 690                 break;
 691         case BPF_S_ANC_HATYPE:  /* if (!skb->dev) return 0;
 692                                  * A = skb->dev->type */
 693                 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
 694                 jit->seen |= SEEN_RET0;
 695                 /* lg %r1,<d(dev)>(%r2) */
 696                 EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
 697                 /* ltgr %r1,%r1 */
 698                 EMIT4(0xb9020011);
 699                 /* jz <ret0> */
 700                 EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
 701                 /* lhi %r5,0 */
 702                 EMIT4(0xa7580000);
 703                 /* icm  %r5,3,<d(type)>(%r1) */
 704                 EMIT4_DISP(0xbf531000, offsetof(struct net_device, type));
 705                 break;
 706         case BPF_S_ANC_RXHASH: /* A = skb->rxhash */
 707                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4);
 708                 /* l %r5,<d(rxhash)>(%r2) */
 709                 EMIT4_DISP(0x58502000, offsetof(struct sk_buff, rxhash));
 710                 break;
 711         case BPF_S_ANC_VLAN_TAG:
 712         case BPF_S_ANC_VLAN_TAG_PRESENT:
 713                 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
 714                 BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
 715                 /* lhi %r5,0 */
 716                 EMIT4(0xa7580000);
 717                 /* icm  %r5,3,<d(vlan_tci)>(%r2) */
 718                 EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, vlan_tci));
 719                 if (filter->code == BPF_S_ANC_VLAN_TAG) {
 720                         /* nill %r5,0xefff */
 721                         EMIT4_IMM(0xa5570000, ~VLAN_TAG_PRESENT);
 722                 } else {
 723                         /* nill %r5,0x1000 */
 724                         EMIT4_IMM(0xa5570000, VLAN_TAG_PRESENT);
 725                         /* srl %r5,12 */
 726                         EMIT4_DISP(0x88500000, 12);
 727                 }
 728                 break;
 729         case BPF_S_ANC_CPU: /* A = smp_processor_id() */
 730 #ifdef CONFIG_SMP
 731                 /* l %r5,<d(cpu_nr)> */
 732                 EMIT4_DISP(0x58500000, offsetof(struct _lowcore, cpu_nr));
 733 #else
 734                 /* lhi %r5,0 */
 735                 EMIT4(0xa7580000);
 736 #endif
 737                 break;
 738         default: /* too complex, give up */
 739                 goto out;
 740         }
 741         addrs[i] = jit->prg - jit->start;
 742         return 0;
 743 out:
 744         return -1;
 745 }
 746
 747 void bpf_jit_compile(struct sk_filter *fp)
 748 {
 749         unsigned long size, prg_len, lit_len;
 750         struct bpf_jit jit, cjit;
 751         unsigned int *addrs;
 752         int pass, i;
 753
 754         if (!bpf_jit_enable)
 755                 return;
 756         addrs = kcalloc(fp->len, sizeof(*addrs), GFP_KERNEL);
 757         if (addrs == NULL)
 758                 return;
 759         memset(&jit, 0, sizeof(cjit));
 760         memset(&cjit, 0, sizeof(cjit));
 761
 762         for (pass = 0; pass < 10; pass++) {
 763                 jit.prg = jit.start;
 764                 jit.lit = jit.mid;
 765
 766                 bpf_jit_prologue(&jit);
 767                 bpf_jit_noleaks(&jit, fp->insns);
 768                 for (i = 0; i < fp->len; i++) {
 769                         if (bpf_jit_insn(&jit, fp->insns + i, addrs, i,
 770                                          i == fp->len - 1))
 771                                 goto out;
 772                 }
 773                 bpf_jit_epilogue(&jit);
 774                 if (jit.start) {
 775                         WARN_ON(jit.prg > cjit.prg || jit.lit > cjit.lit);
 776                         if (memcmp(&jit, &cjit, sizeof(jit)) == 0)
 777                                 break;
 778                 } else if (jit.prg == cjit.prg && jit.lit == cjit.lit) {
 779                         prg_len = jit.prg - jit.start;
 780                         lit_len = jit.lit - jit.mid;
 781                         size = max_t(unsigned long, prg_len + lit_len,
 782                                      sizeof(struct work_struct));
 783                         if (size >= BPF_SIZE_MAX)
 784                                 goto out;
 785                         jit.start = module_alloc(size);
 786                         if (!jit.start)
 787                                 goto out;
 788                         jit.prg = jit.mid = jit.start + prg_len;
 789                         jit.lit = jit.end = jit.start + prg_len + lit_len;
 790                         jit.base_ip += (unsigned long) jit.start;
 791                         jit.exit_ip += (unsigned long) jit.start;
 792                         jit.ret0_ip += (unsigned long) jit.start;
 793                 }
 794                 cjit = jit;
 795         }
 796         if (bpf_jit_enable > 1) {
 797                 pr_err("flen=%d proglen=%lu pass=%d image=%p\n",
 798                        fp->len, jit.end - jit.start, pass, jit.start);
 799                 if (jit.start) {
 800                         printk(KERN_ERR "JIT code:\n");
 801                         print_fn_code(jit.start, jit.mid - jit.start);
 802                         print_hex_dump(KERN_ERR, "JIT literals:\n",
 803                                        DUMP_PREFIX_ADDRESS, 16, 1,
 804                                        jit.mid, jit.end - jit.mid, false);
 805                 }
 806         }
 807         if (jit.start)
 808                 fp->bpf_func = (void *) jit.start;
 809 out:
 810         kfree(addrs);
 811 }
 812
 813 static void jit_free_defer(struct work_struct *arg)
 814 {
 815         module_free(NULL, arg);
 816 }
 817
 818 /* run from softirq, we must use a work_struct to call
 819  * module_free() from process context
 820  */
 821 void bpf_jit_free(struct sk_filter *fp)
 822 {
 823         struct work_struct *work;
 824
 825         if (fp->bpf_func == sk_run_filter)
 826                 return;
 827         work = (struct work_struct *)fp->bpf_func;
 828         INIT_WORK(work, jit_free_defer);
 829         schedule_work(work);
 830 }