1 /* 2 * BPF JIT compiler for ARM64 3 * 4 * Copyright (C) 2014 Zi Shen Lim <zlim.lnx@gmail.com> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program. If not, see <http://www.gnu.org/licenses/>. 17 */ 18 19 #define pr_fmt(fmt) "bpf_jit: " fmt 20 21 #include <linux/filter.h> 22 #include <linux/printk.h> 23 #include <linux/skbuff.h> 24 #include <linux/slab.h> 25 26 #include <asm/byteorder.h> 27 #include <asm/cacheflush.h> 28 #include <asm/debug-monitors.h> 29 30 #include "bpf_jit.h" 31 32 int bpf_jit_enable __read_mostly; 33 34 #define TMP_REG_1 (MAX_BPF_REG + 0) 35 #define TMP_REG_2 (MAX_BPF_REG + 1) 36 37 /* Map BPF registers to A64 registers */ 38 static const int bpf2a64[] = { 39 /* return value from in-kernel function, and exit value from eBPF */ 40 [BPF_REG_0] = A64_R(7), 41 /* arguments from eBPF program to in-kernel function */ 42 [BPF_REG_1] = A64_R(0), 43 [BPF_REG_2] = A64_R(1), 44 [BPF_REG_3] = A64_R(2), 45 [BPF_REG_4] = A64_R(3), 46 [BPF_REG_5] = A64_R(4), 47 /* callee saved registers that in-kernel function will preserve */ 48 [BPF_REG_6] = A64_R(19), 49 [BPF_REG_7] = A64_R(20), 50 [BPF_REG_8] = A64_R(21), 51 [BPF_REG_9] = A64_R(22), 52 /* read-only frame pointer to access stack */ 53 [BPF_REG_FP] = A64_FP, 54 /* temporary register for internal BPF JIT */ 55 [TMP_REG_1] = A64_R(23), 56 [TMP_REG_2] = A64_R(24), 57 }; 58 59 struct jit_ctx { 60 const struct bpf_prog *prog; 61 int idx; 62 int tmp_used; 63 int epilogue_offset; 64 int *offset; 65 u32 *image; 66 }; 67 68 static inline void emit(const u32 insn, struct jit_ctx *ctx) 69 { 70 if (ctx->image != NULL) 71 ctx->image[ctx->idx] = cpu_to_le32(insn); 72 73 ctx->idx++; 74 } 75 76 static inline void emit_a64_mov_i64(const int reg, const u64 val, 77 struct jit_ctx *ctx) 78 { 79 u64 tmp = val; 80 int shift = 0; 81 82 emit(A64_MOVZ(1, reg, tmp & 0xffff, shift), ctx); 83 tmp >>= 16; 84 shift += 16; 85 while (tmp) { 86 if (tmp & 0xffff) 87 emit(A64_MOVK(1, reg, tmp & 0xffff, shift), ctx); 88 tmp >>= 16; 89 shift += 16; 90 } 91 } 92 93 static inline void emit_a64_mov_i(const int is64, const int reg, 94 const s32 val, struct jit_ctx *ctx) 95 { 96 u16 hi = val >> 16; 97 u16 lo = val & 0xffff; 98 99 if (hi & 0x8000) { 100 if (hi == 0xffff) { 101 emit(A64_MOVN(is64, reg, (u16)~lo, 0), ctx); 102 } else { 103 emit(A64_MOVN(is64, reg, (u16)~hi, 16), ctx); 104 emit(A64_MOVK(is64, reg, lo, 0), ctx); 105 } 106 } else { 107 emit(A64_MOVZ(is64, reg, lo, 0), ctx); 108 if (hi) 109 emit(A64_MOVK(is64, reg, hi, 16), ctx); 110 } 111 } 112 113 static inline int bpf2a64_offset(int bpf_to, int bpf_from, 114 const struct jit_ctx *ctx) 115 { 116 int to = ctx->offset[bpf_to + 1]; 117 /* -1 to account for the Branch instruction */ 118 int from = ctx->offset[bpf_from + 1] - 1; 119 120 return to - from; 121 } 122 123 static void jit_fill_hole(void *area, unsigned int size) 124 { 125 u32 *ptr; 126 /* We are guaranteed to have aligned memory. */ 127 for (ptr = area; size >= sizeof(u32); size -= sizeof(u32)) 128 *ptr++ = cpu_to_le32(AARCH64_BREAK_FAULT); 129 } 130 131 static inline int epilogue_offset(const struct jit_ctx *ctx) 132 { 133 int to = ctx->epilogue_offset; 134 int from = ctx->idx; 135 136 return to - from; 137 } 138 139 /* Stack must be multiples of 16B */ 140 #define STACK_ALIGN(sz) (((sz) + 15) & ~15) 141 142 static void build_prologue(struct jit_ctx *ctx) 143 { 144 const u8 r6 = bpf2a64[BPF_REG_6]; 145 const u8 r7 = bpf2a64[BPF_REG_7]; 146 const u8 r8 = bpf2a64[BPF_REG_8]; 147 const u8 r9 = bpf2a64[BPF_REG_9]; 148 const u8 fp = bpf2a64[BPF_REG_FP]; 149 const u8 ra = bpf2a64[BPF_REG_A]; 150 const u8 rx = bpf2a64[BPF_REG_X]; 151 const u8 tmp1 = bpf2a64[TMP_REG_1]; 152 const u8 tmp2 = bpf2a64[TMP_REG_2]; 153 int stack_size = MAX_BPF_STACK; 154 155 stack_size += 4; /* extra for skb_copy_bits buffer */ 156 stack_size = STACK_ALIGN(stack_size); 157 158 /* Save callee-saved register */ 159 emit(A64_PUSH(r6, r7, A64_SP), ctx); 160 emit(A64_PUSH(r8, r9, A64_SP), ctx); 161 if (ctx->tmp_used) 162 emit(A64_PUSH(tmp1, tmp2, A64_SP), ctx); 163 164 /* Set up BPF stack */ 165 emit(A64_SUB_I(1, A64_SP, A64_SP, stack_size), ctx); 166 167 /* Set up frame pointer */ 168 emit(A64_MOV(1, fp, A64_SP), ctx); 169 170 /* Clear registers A and X */ 171 emit_a64_mov_i64(ra, 0, ctx); 172 emit_a64_mov_i64(rx, 0, ctx); 173 } 174 175 static void build_epilogue(struct jit_ctx *ctx) 176 { 177 const u8 r0 = bpf2a64[BPF_REG_0]; 178 const u8 r6 = bpf2a64[BPF_REG_6]; 179 const u8 r7 = bpf2a64[BPF_REG_7]; 180 const u8 r8 = bpf2a64[BPF_REG_8]; 181 const u8 r9 = bpf2a64[BPF_REG_9]; 182 const u8 fp = bpf2a64[BPF_REG_FP]; 183 const u8 tmp1 = bpf2a64[TMP_REG_1]; 184 const u8 tmp2 = bpf2a64[TMP_REG_2]; 185 int stack_size = MAX_BPF_STACK; 186 187 stack_size += 4; /* extra for skb_copy_bits buffer */ 188 stack_size = STACK_ALIGN(stack_size); 189 190 /* We're done with BPF stack */ 191 emit(A64_ADD_I(1, A64_SP, A64_SP, stack_size), ctx); 192 193 /* Restore callee-saved register */ 194 if (ctx->tmp_used) 195 emit(A64_POP(tmp1, tmp2, A64_SP), ctx); 196 emit(A64_POP(r8, r9, A64_SP), ctx); 197 emit(A64_POP(r6, r7, A64_SP), ctx); 198 199 /* Restore frame pointer */ 200 emit(A64_MOV(1, fp, A64_SP), ctx); 201 202 /* Set return value */ 203 emit(A64_MOV(1, A64_R(0), r0), ctx); 204 205 emit(A64_RET(A64_LR), ctx); 206 } 207 208 /* JITs an eBPF instruction. 209 * Returns: 210 * 0 - successfully JITed an 8-byte eBPF instruction. 211 * >0 - successfully JITed a 16-byte eBPF instruction. 212 * <0 - failed to JIT. 213 */ 214 static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) 215 { 216 const u8 code = insn->code; 217 const u8 dst = bpf2a64[insn->dst_reg]; 218 const u8 src = bpf2a64[insn->src_reg]; 219 const u8 tmp = bpf2a64[TMP_REG_1]; 220 const u8 tmp2 = bpf2a64[TMP_REG_2]; 221 const s16 off = insn->off; 222 const s32 imm = insn->imm; 223 const int i = insn - ctx->prog->insnsi; 224 const bool is64 = BPF_CLASS(code) == BPF_ALU64; 225 u8 jmp_cond; 226 s32 jmp_offset; 227 228 switch (code) { 229 /* dst = src */ 230 case BPF_ALU | BPF_MOV | BPF_X: 231 case BPF_ALU64 | BPF_MOV | BPF_X: 232 emit(A64_MOV(is64, dst, src), ctx); 233 break; 234 /* dst = dst OP src */ 235 case BPF_ALU | BPF_ADD | BPF_X: 236 case BPF_ALU64 | BPF_ADD | BPF_X: 237 emit(A64_ADD(is64, dst, dst, src), ctx); 238 break; 239 case BPF_ALU | BPF_SUB | BPF_X: 240 case BPF_ALU64 | BPF_SUB | BPF_X: 241 emit(A64_SUB(is64, dst, dst, src), ctx); 242 break; 243 case BPF_ALU | BPF_AND | BPF_X: 244 case BPF_ALU64 | BPF_AND | BPF_X: 245 emit(A64_AND(is64, dst, dst, src), ctx); 246 break; 247 case BPF_ALU | BPF_OR | BPF_X: 248 case BPF_ALU64 | BPF_OR | BPF_X: 249 emit(A64_ORR(is64, dst, dst, src), ctx); 250 break; 251 case BPF_ALU | BPF_XOR | BPF_X: 252 case BPF_ALU64 | BPF_XOR | BPF_X: 253 emit(A64_EOR(is64, dst, dst, src), ctx); 254 break; 255 case BPF_ALU | BPF_MUL | BPF_X: 256 case BPF_ALU64 | BPF_MUL | BPF_X: 257 emit(A64_MUL(is64, dst, dst, src), ctx); 258 break; 259 case BPF_ALU | BPF_DIV | BPF_X: 260 case BPF_ALU64 | BPF_DIV | BPF_X: 261 emit(A64_UDIV(is64, dst, dst, src), ctx); 262 break; 263 case BPF_ALU | BPF_MOD | BPF_X: 264 case BPF_ALU64 | BPF_MOD | BPF_X: 265 ctx->tmp_used = 1; 266 emit(A64_UDIV(is64, tmp, dst, src), ctx); 267 emit(A64_MUL(is64, tmp, tmp, src), ctx); 268 emit(A64_SUB(is64, dst, dst, tmp), ctx); 269 break; 270 case BPF_ALU | BPF_LSH | BPF_X: 271 case BPF_ALU64 | BPF_LSH | BPF_X: 272 emit(A64_LSLV(is64, dst, dst, src), ctx); 273 break; 274 case BPF_ALU | BPF_RSH | BPF_X: 275 case BPF_ALU64 | BPF_RSH | BPF_X: 276 emit(A64_LSRV(is64, dst, dst, src), ctx); 277 break; 278 case BPF_ALU | BPF_ARSH | BPF_X: 279 case BPF_ALU64 | BPF_ARSH | BPF_X: 280 emit(A64_ASRV(is64, dst, dst, src), ctx); 281 break; 282 /* dst = -dst */ 283 case BPF_ALU | BPF_NEG: 284 case BPF_ALU64 | BPF_NEG: 285 emit(A64_NEG(is64, dst, dst), ctx); 286 break; 287 /* dst = BSWAP##imm(dst) */ 288 case BPF_ALU | BPF_END | BPF_FROM_LE: 289 case BPF_ALU | BPF_END | BPF_FROM_BE: 290 #ifdef CONFIG_CPU_BIG_ENDIAN 291 if (BPF_SRC(code) == BPF_FROM_BE) 292 break; 293 #else /* !CONFIG_CPU_BIG_ENDIAN */ 294 if (BPF_SRC(code) == BPF_FROM_LE) 295 break; 296 #endif 297 switch (imm) { 298 case 16: 299 emit(A64_REV16(is64, dst, dst), ctx); 300 break; 301 case 32: 302 emit(A64_REV32(is64, dst, dst), ctx); 303 break; 304 case 64: 305 emit(A64_REV64(dst, dst), ctx); 306 break; 307 } 308 break; 309 /* dst = imm */ 310 case BPF_ALU | BPF_MOV | BPF_K: 311 case BPF_ALU64 | BPF_MOV | BPF_K: 312 emit_a64_mov_i(is64, dst, imm, ctx); 313 break; 314 /* dst = dst OP imm */ 315 case BPF_ALU | BPF_ADD | BPF_K: 316 case BPF_ALU64 | BPF_ADD | BPF_K: 317 ctx->tmp_used = 1; 318 emit_a64_mov_i(is64, tmp, imm, ctx); 319 emit(A64_ADD(is64, dst, dst, tmp), ctx); 320 break; 321 case BPF_ALU | BPF_SUB | BPF_K: 322 case BPF_ALU64 | BPF_SUB | BPF_K: 323 ctx->tmp_used = 1; 324 emit_a64_mov_i(is64, tmp, imm, ctx); 325 emit(A64_SUB(is64, dst, dst, tmp), ctx); 326 break; 327 case BPF_ALU | BPF_AND | BPF_K: 328 case BPF_ALU64 | BPF_AND | BPF_K: 329 ctx->tmp_used = 1; 330 emit_a64_mov_i(is64, tmp, imm, ctx); 331 emit(A64_AND(is64, dst, dst, tmp), ctx); 332 break; 333 case BPF_ALU | BPF_OR | BPF_K: 334 case BPF_ALU64 | BPF_OR | BPF_K: 335 ctx->tmp_used = 1; 336 emit_a64_mov_i(is64, tmp, imm, ctx); 337 emit(A64_ORR(is64, dst, dst, tmp), ctx); 338 break; 339 case BPF_ALU | BPF_XOR | BPF_K: 340 case BPF_ALU64 | BPF_XOR | BPF_K: 341 ctx->tmp_used = 1; 342 emit_a64_mov_i(is64, tmp, imm, ctx); 343 emit(A64_EOR(is64, dst, dst, tmp), ctx); 344 break; 345 case BPF_ALU | BPF_MUL | BPF_K: 346 case BPF_ALU64 | BPF_MUL | BPF_K: 347 ctx->tmp_used = 1; 348 emit_a64_mov_i(is64, tmp, imm, ctx); 349 emit(A64_MUL(is64, dst, dst, tmp), ctx); 350 break; 351 case BPF_ALU | BPF_DIV | BPF_K: 352 case BPF_ALU64 | BPF_DIV | BPF_K: 353 ctx->tmp_used = 1; 354 emit_a64_mov_i(is64, tmp, imm, ctx); 355 emit(A64_UDIV(is64, dst, dst, tmp), ctx); 356 break; 357 case BPF_ALU | BPF_MOD | BPF_K: 358 case BPF_ALU64 | BPF_MOD | BPF_K: 359 ctx->tmp_used = 1; 360 emit_a64_mov_i(is64, tmp2, imm, ctx); 361 emit(A64_UDIV(is64, tmp, dst, tmp2), ctx); 362 emit(A64_MUL(is64, tmp, tmp, tmp2), ctx); 363 emit(A64_SUB(is64, dst, dst, tmp), ctx); 364 break; 365 case BPF_ALU | BPF_LSH | BPF_K: 366 case BPF_ALU64 | BPF_LSH | BPF_K: 367 emit(A64_LSL(is64, dst, dst, imm), ctx); 368 break; 369 case BPF_ALU | BPF_RSH | BPF_K: 370 case BPF_ALU64 | BPF_RSH | BPF_K: 371 emit(A64_LSR(is64, dst, dst, imm), ctx); 372 break; 373 case BPF_ALU | BPF_ARSH | BPF_K: 374 case BPF_ALU64 | BPF_ARSH | BPF_K: 375 emit(A64_ASR(is64, dst, dst, imm), ctx); 376 break; 377 378 #define check_imm(bits, imm) do { \ 379 if ((((imm) > 0) && ((imm) >> (bits))) || \ 380 (((imm) < 0) && (~(imm) >> (bits)))) { \ 381 pr_info("[%2d] imm=%d(0x%x) out of range\n", \ 382 i, imm, imm); \ 383 return -EINVAL; \ 384 } \ 385 } while (0) 386 #define check_imm19(imm) check_imm(19, imm) 387 #define check_imm26(imm) check_imm(26, imm) 388 389 /* JUMP off */ 390 case BPF_JMP | BPF_JA: 391 jmp_offset = bpf2a64_offset(i + off, i, ctx); 392 check_imm26(jmp_offset); 393 emit(A64_B(jmp_offset), ctx); 394 break; 395 /* IF (dst COND src) JUMP off */ 396 case BPF_JMP | BPF_JEQ | BPF_X: 397 case BPF_JMP | BPF_JGT | BPF_X: 398 case BPF_JMP | BPF_JGE | BPF_X: 399 case BPF_JMP | BPF_JNE | BPF_X: 400 case BPF_JMP | BPF_JSGT | BPF_X: 401 case BPF_JMP | BPF_JSGE | BPF_X: 402 emit(A64_CMP(1, dst, src), ctx); 403 emit_cond_jmp: 404 jmp_offset = bpf2a64_offset(i + off, i, ctx); 405 check_imm19(jmp_offset); 406 switch (BPF_OP(code)) { 407 case BPF_JEQ: 408 jmp_cond = A64_COND_EQ; 409 break; 410 case BPF_JGT: 411 jmp_cond = A64_COND_HI; 412 break; 413 case BPF_JGE: 414 jmp_cond = A64_COND_CS; 415 break; 416 case BPF_JNE: 417 jmp_cond = A64_COND_NE; 418 break; 419 case BPF_JSGT: 420 jmp_cond = A64_COND_GT; 421 break; 422 case BPF_JSGE: 423 jmp_cond = A64_COND_GE; 424 break; 425 default: 426 return -EFAULT; 427 } 428 emit(A64_B_(jmp_cond, jmp_offset), ctx); 429 break; 430 case BPF_JMP | BPF_JSET | BPF_X: 431 emit(A64_TST(1, dst, src), ctx); 432 goto emit_cond_jmp; 433 /* IF (dst COND imm) JUMP off */ 434 case BPF_JMP | BPF_JEQ | BPF_K: 435 case BPF_JMP | BPF_JGT | BPF_K: 436 case BPF_JMP | BPF_JGE | BPF_K: 437 case BPF_JMP | BPF_JNE | BPF_K: 438 case BPF_JMP | BPF_JSGT | BPF_K: 439 case BPF_JMP | BPF_JSGE | BPF_K: 440 ctx->tmp_used = 1; 441 emit_a64_mov_i(1, tmp, imm, ctx); 442 emit(A64_CMP(1, dst, tmp), ctx); 443 goto emit_cond_jmp; 444 case BPF_JMP | BPF_JSET | BPF_K: 445 ctx->tmp_used = 1; 446 emit_a64_mov_i(1, tmp, imm, ctx); 447 emit(A64_TST(1, dst, tmp), ctx); 448 goto emit_cond_jmp; 449 /* function call */ 450 case BPF_JMP | BPF_CALL: 451 { 452 const u8 r0 = bpf2a64[BPF_REG_0]; 453 const u64 func = (u64)__bpf_call_base + imm; 454 455 ctx->tmp_used = 1; 456 emit_a64_mov_i64(tmp, func, ctx); 457 emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx); 458 emit(A64_MOV(1, A64_FP, A64_SP), ctx); 459 emit(A64_BLR(tmp), ctx); 460 emit(A64_MOV(1, r0, A64_R(0)), ctx); 461 emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx); 462 break; 463 } 464 /* function return */ 465 case BPF_JMP | BPF_EXIT: 466 /* Optimization: when last instruction is EXIT, 467 simply fallthrough to epilogue. */ 468 if (i == ctx->prog->len - 1) 469 break; 470 jmp_offset = epilogue_offset(ctx); 471 check_imm26(jmp_offset); 472 emit(A64_B(jmp_offset), ctx); 473 break; 474 475 /* dst = imm64 */ 476 case BPF_LD | BPF_IMM | BPF_DW: 477 { 478 const struct bpf_insn insn1 = insn[1]; 479 u64 imm64; 480 481 if (insn1.code != 0 || insn1.src_reg != 0 || 482 insn1.dst_reg != 0 || insn1.off != 0) { 483 /* Note: verifier in BPF core must catch invalid 484 * instructions. 485 */ 486 pr_err_once("Invalid BPF_LD_IMM64 instruction\n"); 487 return -EINVAL; 488 } 489 490 imm64 = (u64)insn1.imm << 32 | imm; 491 emit_a64_mov_i64(dst, imm64, ctx); 492 493 return 1; 494 } 495 496 /* LDX: dst = *(size *)(src + off) */ 497 case BPF_LDX | BPF_MEM | BPF_W: 498 case BPF_LDX | BPF_MEM | BPF_H: 499 case BPF_LDX | BPF_MEM | BPF_B: 500 case BPF_LDX | BPF_MEM | BPF_DW: 501 ctx->tmp_used = 1; 502 emit_a64_mov_i(1, tmp, off, ctx); 503 switch (BPF_SIZE(code)) { 504 case BPF_W: 505 emit(A64_LDR32(dst, src, tmp), ctx); 506 break; 507 case BPF_H: 508 emit(A64_LDRH(dst, src, tmp), ctx); 509 break; 510 case BPF_B: 511 emit(A64_LDRB(dst, src, tmp), ctx); 512 break; 513 case BPF_DW: 514 emit(A64_LDR64(dst, src, tmp), ctx); 515 break; 516 } 517 break; 518 519 /* ST: *(size *)(dst + off) = imm */ 520 case BPF_ST | BPF_MEM | BPF_W: 521 case BPF_ST | BPF_MEM | BPF_H: 522 case BPF_ST | BPF_MEM | BPF_B: 523 case BPF_ST | BPF_MEM | BPF_DW: 524 goto notyet; 525 526 /* STX: *(size *)(dst + off) = src */ 527 case BPF_STX | BPF_MEM | BPF_W: 528 case BPF_STX | BPF_MEM | BPF_H: 529 case BPF_STX | BPF_MEM | BPF_B: 530 case BPF_STX | BPF_MEM | BPF_DW: 531 ctx->tmp_used = 1; 532 emit_a64_mov_i(1, tmp, off, ctx); 533 switch (BPF_SIZE(code)) { 534 case BPF_W: 535 emit(A64_STR32(src, dst, tmp), ctx); 536 break; 537 case BPF_H: 538 emit(A64_STRH(src, dst, tmp), ctx); 539 break; 540 case BPF_B: 541 emit(A64_STRB(src, dst, tmp), ctx); 542 break; 543 case BPF_DW: 544 emit(A64_STR64(src, dst, tmp), ctx); 545 break; 546 } 547 break; 548 /* STX XADD: lock *(u32 *)(dst + off) += src */ 549 case BPF_STX | BPF_XADD | BPF_W: 550 /* STX XADD: lock *(u64 *)(dst + off) += src */ 551 case BPF_STX | BPF_XADD | BPF_DW: 552 goto notyet; 553 554 /* R0 = ntohx(*(size *)(((struct sk_buff *)R6)->data + imm)) */ 555 case BPF_LD | BPF_ABS | BPF_W: 556 case BPF_LD | BPF_ABS | BPF_H: 557 case BPF_LD | BPF_ABS | BPF_B: 558 /* R0 = ntohx(*(size *)(((struct sk_buff *)R6)->data + src + imm)) */ 559 case BPF_LD | BPF_IND | BPF_W: 560 case BPF_LD | BPF_IND | BPF_H: 561 case BPF_LD | BPF_IND | BPF_B: 562 { 563 const u8 r0 = bpf2a64[BPF_REG_0]; /* r0 = return value */ 564 const u8 r6 = bpf2a64[BPF_REG_6]; /* r6 = pointer to sk_buff */ 565 const u8 fp = bpf2a64[BPF_REG_FP]; 566 const u8 r1 = bpf2a64[BPF_REG_1]; /* r1: struct sk_buff *skb */ 567 const u8 r2 = bpf2a64[BPF_REG_2]; /* r2: int k */ 568 const u8 r3 = bpf2a64[BPF_REG_3]; /* r3: unsigned int size */ 569 const u8 r4 = bpf2a64[BPF_REG_4]; /* r4: void *buffer */ 570 const u8 r5 = bpf2a64[BPF_REG_5]; /* r5: void *(*func)(...) */ 571 int size; 572 573 emit(A64_MOV(1, r1, r6), ctx); 574 emit_a64_mov_i(0, r2, imm, ctx); 575 if (BPF_MODE(code) == BPF_IND) 576 emit(A64_ADD(0, r2, r2, src), ctx); 577 switch (BPF_SIZE(code)) { 578 case BPF_W: 579 size = 4; 580 break; 581 case BPF_H: 582 size = 2; 583 break; 584 case BPF_B: 585 size = 1; 586 break; 587 default: 588 return -EINVAL; 589 } 590 emit_a64_mov_i64(r3, size, ctx); 591 emit(A64_ADD_I(1, r4, fp, MAX_BPF_STACK), ctx); 592 emit_a64_mov_i64(r5, (unsigned long)bpf_load_pointer, ctx); 593 emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx); 594 emit(A64_MOV(1, A64_FP, A64_SP), ctx); 595 emit(A64_BLR(r5), ctx); 596 emit(A64_MOV(1, r0, A64_R(0)), ctx); 597 emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx); 598 599 jmp_offset = epilogue_offset(ctx); 600 check_imm19(jmp_offset); 601 emit(A64_CBZ(1, r0, jmp_offset), ctx); 602 emit(A64_MOV(1, r5, r0), ctx); 603 switch (BPF_SIZE(code)) { 604 case BPF_W: 605 emit(A64_LDR32(r0, r5, A64_ZR), ctx); 606 #ifndef CONFIG_CPU_BIG_ENDIAN 607 emit(A64_REV32(0, r0, r0), ctx); 608 #endif 609 break; 610 case BPF_H: 611 emit(A64_LDRH(r0, r5, A64_ZR), ctx); 612 #ifndef CONFIG_CPU_BIG_ENDIAN 613 emit(A64_REV16(0, r0, r0), ctx); 614 #endif 615 break; 616 case BPF_B: 617 emit(A64_LDRB(r0, r5, A64_ZR), ctx); 618 break; 619 } 620 break; 621 } 622 notyet: 623 pr_info_once("*** NOT YET: opcode %02x ***\n", code); 624 return -EFAULT; 625 626 default: 627 pr_err_once("unknown opcode %02x\n", code); 628 return -EINVAL; 629 } 630 631 return 0; 632 } 633 634 static int build_body(struct jit_ctx *ctx) 635 { 636 const struct bpf_prog *prog = ctx->prog; 637 int i; 638 639 for (i = 0; i < prog->len; i++) { 640 const struct bpf_insn *insn = &prog->insnsi[i]; 641 int ret; 642 643 if (ctx->image == NULL) 644 ctx->offset[i] = ctx->idx; 645 646 ret = build_insn(insn, ctx); 647 if (ret > 0) { 648 i++; 649 continue; 650 } 651 if (ret) 652 return ret; 653 } 654 655 return 0; 656 } 657 658 static inline void bpf_flush_icache(void *start, void *end) 659 { 660 flush_icache_range((unsigned long)start, (unsigned long)end); 661 } 662 663 void bpf_jit_compile(struct bpf_prog *prog) 664 { 665 /* Nothing to do here. We support Internal BPF. */ 666 } 667 668 void bpf_int_jit_compile(struct bpf_prog *prog) 669 { 670 struct bpf_binary_header *header; 671 struct jit_ctx ctx; 672 int image_size; 673 u8 *image_ptr; 674 675 if (!bpf_jit_enable) 676 return; 677 678 if (!prog || !prog->len) 679 return; 680 681 memset(&ctx, 0, sizeof(ctx)); 682 ctx.prog = prog; 683 684 ctx.offset = kcalloc(prog->len, sizeof(int), GFP_KERNEL); 685 if (ctx.offset == NULL) 686 return; 687 688 /* 1. Initial fake pass to compute ctx->idx. */ 689 690 /* Fake pass to fill in ctx->offset and ctx->tmp_used. */ 691 if (build_body(&ctx)) 692 goto out; 693 694 build_prologue(&ctx); 695 696 ctx.epilogue_offset = ctx.idx; 697 build_epilogue(&ctx); 698 699 /* Now we know the actual image size. */ 700 image_size = sizeof(u32) * ctx.idx; 701 header = bpf_jit_binary_alloc(image_size, &image_ptr, 702 sizeof(u32), jit_fill_hole); 703 if (header == NULL) 704 goto out; 705 706 /* 2. Now, the actual pass. */ 707 708 ctx.image = (u32 *)image_ptr; 709 ctx.idx = 0; 710 711 build_prologue(&ctx); 712 713 if (build_body(&ctx)) { 714 bpf_jit_binary_free(header); 715 goto out; 716 } 717 718 build_epilogue(&ctx); 719 720 /* And we're done. */ 721 if (bpf_jit_enable > 1) 722 bpf_jit_dump(prog->len, image_size, 2, ctx.image); 723 724 bpf_flush_icache(ctx.image, ctx.image + ctx.idx); 725 726 set_memory_ro((unsigned long)header, header->pages); 727 prog->bpf_func = (void *)ctx.image; 728 prog->jited = true; 729 out: 730 kfree(ctx.offset); 731 } 732 733 void bpf_jit_free(struct bpf_prog *prog) 734 { 735 unsigned long addr = (unsigned long)prog->bpf_func & PAGE_MASK; 736 struct bpf_binary_header *header = (void *)addr; 737 738 if (!prog->jited) 739 goto free_filter; 740 741 set_memory_rw(addr, header->pages); 742 bpf_jit_binary_free(header); 743 744 free_filter: 745 bpf_prog_unlock_free(prog); 746 } 747