1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * BPF JIT compiler for LoongArch 4 * 5 * Copyright (C) 2022 Loongson Technology Corporation Limited 6 */ 7 #include "bpf_jit.h" 8 9 #define REG_TCC LOONGARCH_GPR_A6 10 #define TCC_SAVED LOONGARCH_GPR_S5 11 12 #define SAVE_RA BIT(0) 13 #define SAVE_TCC BIT(1) 14 15 static const int regmap[] = { 16 /* return value from in-kernel function, and exit value for eBPF program */ 17 [BPF_REG_0] = LOONGARCH_GPR_A5, 18 /* arguments from eBPF program to in-kernel function */ 19 [BPF_REG_1] = LOONGARCH_GPR_A0, 20 [BPF_REG_2] = LOONGARCH_GPR_A1, 21 [BPF_REG_3] = LOONGARCH_GPR_A2, 22 [BPF_REG_4] = LOONGARCH_GPR_A3, 23 [BPF_REG_5] = LOONGARCH_GPR_A4, 24 /* callee saved registers that in-kernel function will preserve */ 25 [BPF_REG_6] = LOONGARCH_GPR_S0, 26 [BPF_REG_7] = LOONGARCH_GPR_S1, 27 [BPF_REG_8] = LOONGARCH_GPR_S2, 28 [BPF_REG_9] = LOONGARCH_GPR_S3, 29 /* read-only frame pointer to access stack */ 30 [BPF_REG_FP] = LOONGARCH_GPR_S4, 31 /* temporary register for blinding constants */ 32 [BPF_REG_AX] = LOONGARCH_GPR_T0, 33 }; 34 35 static void mark_call(struct jit_ctx *ctx) 36 { 37 ctx->flags |= SAVE_RA; 38 } 39 40 static void mark_tail_call(struct jit_ctx *ctx) 41 { 42 ctx->flags |= SAVE_TCC; 43 } 44 45 static bool seen_call(struct jit_ctx *ctx) 46 { 47 return (ctx->flags & SAVE_RA); 48 } 49 50 static bool seen_tail_call(struct jit_ctx *ctx) 51 { 52 return (ctx->flags & SAVE_TCC); 53 } 54 55 static u8 tail_call_reg(struct jit_ctx *ctx) 56 { 57 if (seen_call(ctx)) 58 return TCC_SAVED; 59 60 return REG_TCC; 61 } 62 63 /* 64 * eBPF prog stack layout: 65 * 66 * high 67 * original $sp ------------> +-------------------------+ <--LOONGARCH_GPR_FP 68 * | $ra | 69 * +-------------------------+ 70 * | $fp | 71 * +-------------------------+ 72 * | $s0 | 73 * +-------------------------+ 74 * | $s1 | 75 * +-------------------------+ 76 * | $s2 | 77 * +-------------------------+ 78 * | $s3 | 79 * +-------------------------+ 80 * | $s4 | 81 * +-------------------------+ 82 * | $s5 | 83 * +-------------------------+ <--BPF_REG_FP 84 * | prog->aux->stack_depth | 85 * | (optional) | 86 * current $sp -------------> +-------------------------+ 87 * low 88 */ 89 static void build_prologue(struct jit_ctx *ctx) 90 { 91 int stack_adjust = 0, store_offset, bpf_stack_adjust; 92 93 bpf_stack_adjust = round_up(ctx->prog->aux->stack_depth, 16); 94 95 /* To store ra, fp, s0, s1, s2, s3, s4 and s5. */ 96 stack_adjust += sizeof(long) * 8; 97 98 stack_adjust = round_up(stack_adjust, 16); 99 stack_adjust += bpf_stack_adjust; 100 101 /* 102 * First instruction initializes the tail call count (TCC). 103 * On tail call we skip this instruction, and the TCC is 104 * passed in REG_TCC from the caller. 105 */ 106 emit_insn(ctx, addid, REG_TCC, LOONGARCH_GPR_ZERO, MAX_TAIL_CALL_CNT); 107 108 emit_insn(ctx, addid, LOONGARCH_GPR_SP, LOONGARCH_GPR_SP, -stack_adjust); 109 110 store_offset = stack_adjust - sizeof(long); 111 emit_insn(ctx, std, LOONGARCH_GPR_RA, LOONGARCH_GPR_SP, store_offset); 112 113 store_offset -= sizeof(long); 114 emit_insn(ctx, std, LOONGARCH_GPR_FP, LOONGARCH_GPR_SP, store_offset); 115 116 store_offset -= sizeof(long); 117 emit_insn(ctx, std, LOONGARCH_GPR_S0, LOONGARCH_GPR_SP, store_offset); 118 119 store_offset -= sizeof(long); 120 emit_insn(ctx, std, LOONGARCH_GPR_S1, LOONGARCH_GPR_SP, store_offset); 121 122 store_offset -= sizeof(long); 123 emit_insn(ctx, std, LOONGARCH_GPR_S2, LOONGARCH_GPR_SP, store_offset); 124 125 store_offset -= sizeof(long); 126 emit_insn(ctx, std, LOONGARCH_GPR_S3, LOONGARCH_GPR_SP, store_offset); 127 128 store_offset -= sizeof(long); 129 emit_insn(ctx, std, LOONGARCH_GPR_S4, LOONGARCH_GPR_SP, store_offset); 130 131 store_offset -= sizeof(long); 132 emit_insn(ctx, std, LOONGARCH_GPR_S5, LOONGARCH_GPR_SP, store_offset); 133 134 emit_insn(ctx, addid, LOONGARCH_GPR_FP, LOONGARCH_GPR_SP, stack_adjust); 135 136 if (bpf_stack_adjust) 137 emit_insn(ctx, addid, regmap[BPF_REG_FP], LOONGARCH_GPR_SP, bpf_stack_adjust); 138 139 /* 140 * Program contains calls and tail calls, so REG_TCC need 141 * to be saved across calls. 142 */ 143 if (seen_tail_call(ctx) && seen_call(ctx)) 144 move_reg(ctx, TCC_SAVED, REG_TCC); 145 146 ctx->stack_size = stack_adjust; 147 } 148 149 static void __build_epilogue(struct jit_ctx *ctx, bool is_tail_call) 150 { 151 int stack_adjust = ctx->stack_size; 152 int load_offset; 153 154 load_offset = stack_adjust - sizeof(long); 155 emit_insn(ctx, ldd, LOONGARCH_GPR_RA, LOONGARCH_GPR_SP, load_offset); 156 157 load_offset -= sizeof(long); 158 emit_insn(ctx, ldd, LOONGARCH_GPR_FP, LOONGARCH_GPR_SP, load_offset); 159 160 load_offset -= sizeof(long); 161 emit_insn(ctx, ldd, LOONGARCH_GPR_S0, LOONGARCH_GPR_SP, load_offset); 162 163 load_offset -= sizeof(long); 164 emit_insn(ctx, ldd, LOONGARCH_GPR_S1, LOONGARCH_GPR_SP, load_offset); 165 166 load_offset -= sizeof(long); 167 emit_insn(ctx, ldd, LOONGARCH_GPR_S2, LOONGARCH_GPR_SP, load_offset); 168 169 load_offset -= sizeof(long); 170 emit_insn(ctx, ldd, LOONGARCH_GPR_S3, LOONGARCH_GPR_SP, load_offset); 171 172 load_offset -= sizeof(long); 173 emit_insn(ctx, ldd, LOONGARCH_GPR_S4, LOONGARCH_GPR_SP, load_offset); 174 175 load_offset -= sizeof(long); 176 emit_insn(ctx, ldd, LOONGARCH_GPR_S5, LOONGARCH_GPR_SP, load_offset); 177 178 emit_insn(ctx, addid, LOONGARCH_GPR_SP, LOONGARCH_GPR_SP, stack_adjust); 179 180 if (!is_tail_call) { 181 /* Set return value */ 182 move_reg(ctx, LOONGARCH_GPR_A0, regmap[BPF_REG_0]); 183 /* Return to the caller */ 184 emit_insn(ctx, jirl, LOONGARCH_GPR_RA, LOONGARCH_GPR_ZERO, 0); 185 } else { 186 /* 187 * Call the next bpf prog and skip the first instruction 188 * of TCC initialization. 189 */ 190 emit_insn(ctx, jirl, LOONGARCH_GPR_T3, LOONGARCH_GPR_ZERO, 1); 191 } 192 } 193 194 static void build_epilogue(struct jit_ctx *ctx) 195 { 196 __build_epilogue(ctx, false); 197 } 198 199 bool bpf_jit_supports_kfunc_call(void) 200 { 201 return true; 202 } 203 204 /* initialized on the first pass of build_body() */ 205 static int out_offset = -1; 206 static int emit_bpf_tail_call(struct jit_ctx *ctx) 207 { 208 int off; 209 u8 tcc = tail_call_reg(ctx); 210 u8 a1 = LOONGARCH_GPR_A1; 211 u8 a2 = LOONGARCH_GPR_A2; 212 u8 t1 = LOONGARCH_GPR_T1; 213 u8 t2 = LOONGARCH_GPR_T2; 214 u8 t3 = LOONGARCH_GPR_T3; 215 const int idx0 = ctx->idx; 216 217 #define cur_offset (ctx->idx - idx0) 218 #define jmp_offset (out_offset - (cur_offset)) 219 220 /* 221 * a0: &ctx 222 * a1: &array 223 * a2: index 224 * 225 * if (index >= array->map.max_entries) 226 * goto out; 227 */ 228 off = offsetof(struct bpf_array, map.max_entries); 229 emit_insn(ctx, ldwu, t1, a1, off); 230 /* bgeu $a2, $t1, jmp_offset */ 231 if (emit_tailcall_jmp(ctx, BPF_JGE, a2, t1, jmp_offset) < 0) 232 goto toofar; 233 234 /* 235 * if (--TCC < 0) 236 * goto out; 237 */ 238 emit_insn(ctx, addid, REG_TCC, tcc, -1); 239 if (emit_tailcall_jmp(ctx, BPF_JSLT, REG_TCC, LOONGARCH_GPR_ZERO, jmp_offset) < 0) 240 goto toofar; 241 242 /* 243 * prog = array->ptrs[index]; 244 * if (!prog) 245 * goto out; 246 */ 247 emit_insn(ctx, alsld, t2, a2, a1, 2); 248 off = offsetof(struct bpf_array, ptrs); 249 emit_insn(ctx, ldd, t2, t2, off); 250 /* beq $t2, $zero, jmp_offset */ 251 if (emit_tailcall_jmp(ctx, BPF_JEQ, t2, LOONGARCH_GPR_ZERO, jmp_offset) < 0) 252 goto toofar; 253 254 /* goto *(prog->bpf_func + 4); */ 255 off = offsetof(struct bpf_prog, bpf_func); 256 emit_insn(ctx, ldd, t3, t2, off); 257 __build_epilogue(ctx, true); 258 259 /* out: */ 260 if (out_offset == -1) 261 out_offset = cur_offset; 262 if (cur_offset != out_offset) { 263 pr_err_once("tail_call out_offset = %d, expected %d!\n", 264 cur_offset, out_offset); 265 return -1; 266 } 267 268 return 0; 269 270 toofar: 271 pr_info_once("tail_call: jump too far\n"); 272 return -1; 273 #undef cur_offset 274 #undef jmp_offset 275 } 276 277 static void emit_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx) 278 { 279 const u8 t1 = LOONGARCH_GPR_T1; 280 const u8 t2 = LOONGARCH_GPR_T2; 281 const u8 t3 = LOONGARCH_GPR_T3; 282 const u8 r0 = regmap[BPF_REG_0]; 283 const u8 src = regmap[insn->src_reg]; 284 const u8 dst = regmap[insn->dst_reg]; 285 const s16 off = insn->off; 286 const s32 imm = insn->imm; 287 const bool isdw = BPF_SIZE(insn->code) == BPF_DW; 288 289 move_imm(ctx, t1, off, false); 290 emit_insn(ctx, addd, t1, dst, t1); 291 move_reg(ctx, t3, src); 292 293 switch (imm) { 294 /* lock *(size *)(dst + off) <op>= src */ 295 case BPF_ADD: 296 if (isdw) 297 emit_insn(ctx, amaddd, t2, t1, src); 298 else 299 emit_insn(ctx, amaddw, t2, t1, src); 300 break; 301 case BPF_AND: 302 if (isdw) 303 emit_insn(ctx, amandd, t2, t1, src); 304 else 305 emit_insn(ctx, amandw, t2, t1, src); 306 break; 307 case BPF_OR: 308 if (isdw) 309 emit_insn(ctx, amord, t2, t1, src); 310 else 311 emit_insn(ctx, amorw, t2, t1, src); 312 break; 313 case BPF_XOR: 314 if (isdw) 315 emit_insn(ctx, amxord, t2, t1, src); 316 else 317 emit_insn(ctx, amxorw, t2, t1, src); 318 break; 319 /* src = atomic_fetch_<op>(dst + off, src) */ 320 case BPF_ADD | BPF_FETCH: 321 if (isdw) { 322 emit_insn(ctx, amaddd, src, t1, t3); 323 } else { 324 emit_insn(ctx, amaddw, src, t1, t3); 325 emit_zext_32(ctx, src, true); 326 } 327 break; 328 case BPF_AND | BPF_FETCH: 329 if (isdw) { 330 emit_insn(ctx, amandd, src, t1, t3); 331 } else { 332 emit_insn(ctx, amandw, src, t1, t3); 333 emit_zext_32(ctx, src, true); 334 } 335 break; 336 case BPF_OR | BPF_FETCH: 337 if (isdw) { 338 emit_insn(ctx, amord, src, t1, t3); 339 } else { 340 emit_insn(ctx, amorw, src, t1, t3); 341 emit_zext_32(ctx, src, true); 342 } 343 break; 344 case BPF_XOR | BPF_FETCH: 345 if (isdw) { 346 emit_insn(ctx, amxord, src, t1, t3); 347 } else { 348 emit_insn(ctx, amxorw, src, t1, t3); 349 emit_zext_32(ctx, src, true); 350 } 351 break; 352 /* src = atomic_xchg(dst + off, src); */ 353 case BPF_XCHG: 354 if (isdw) { 355 emit_insn(ctx, amswapd, src, t1, t3); 356 } else { 357 emit_insn(ctx, amswapw, src, t1, t3); 358 emit_zext_32(ctx, src, true); 359 } 360 break; 361 /* r0 = atomic_cmpxchg(dst + off, r0, src); */ 362 case BPF_CMPXCHG: 363 move_reg(ctx, t2, r0); 364 if (isdw) { 365 emit_insn(ctx, lld, r0, t1, 0); 366 emit_insn(ctx, bne, t2, r0, 4); 367 move_reg(ctx, t3, src); 368 emit_insn(ctx, scd, t3, t1, 0); 369 emit_insn(ctx, beq, t3, LOONGARCH_GPR_ZERO, -4); 370 } else { 371 emit_insn(ctx, llw, r0, t1, 0); 372 emit_zext_32(ctx, t2, true); 373 emit_zext_32(ctx, r0, true); 374 emit_insn(ctx, bne, t2, r0, 4); 375 move_reg(ctx, t3, src); 376 emit_insn(ctx, scw, t3, t1, 0); 377 emit_insn(ctx, beq, t3, LOONGARCH_GPR_ZERO, -6); 378 emit_zext_32(ctx, r0, true); 379 } 380 break; 381 } 382 } 383 384 static bool is_signed_bpf_cond(u8 cond) 385 { 386 return cond == BPF_JSGT || cond == BPF_JSLT || 387 cond == BPF_JSGE || cond == BPF_JSLE; 388 } 389 390 #define BPF_FIXUP_REG_MASK GENMASK(31, 27) 391 #define BPF_FIXUP_OFFSET_MASK GENMASK(26, 0) 392 393 bool ex_handler_bpf(const struct exception_table_entry *ex, 394 struct pt_regs *regs) 395 { 396 int dst_reg = FIELD_GET(BPF_FIXUP_REG_MASK, ex->fixup); 397 off_t offset = FIELD_GET(BPF_FIXUP_OFFSET_MASK, ex->fixup); 398 399 regs->regs[dst_reg] = 0; 400 regs->csr_era = (unsigned long)&ex->fixup - offset; 401 402 return true; 403 } 404 405 /* For accesses to BTF pointers, add an entry to the exception table */ 406 static int add_exception_handler(const struct bpf_insn *insn, 407 struct jit_ctx *ctx, 408 int dst_reg) 409 { 410 unsigned long pc; 411 off_t offset; 412 struct exception_table_entry *ex; 413 414 if (!ctx->image || !ctx->prog->aux->extable || BPF_MODE(insn->code) != BPF_PROBE_MEM) 415 return 0; 416 417 if (WARN_ON_ONCE(ctx->num_exentries >= ctx->prog->aux->num_exentries)) 418 return -EINVAL; 419 420 ex = &ctx->prog->aux->extable[ctx->num_exentries]; 421 pc = (unsigned long)&ctx->image[ctx->idx - 1]; 422 423 offset = pc - (long)&ex->insn; 424 if (WARN_ON_ONCE(offset >= 0 || offset < INT_MIN)) 425 return -ERANGE; 426 427 ex->insn = offset; 428 429 /* 430 * Since the extable follows the program, the fixup offset is always 431 * negative and limited to BPF_JIT_REGION_SIZE. Store a positive value 432 * to keep things simple, and put the destination register in the upper 433 * bits. We don't need to worry about buildtime or runtime sort 434 * modifying the upper bits because the table is already sorted, and 435 * isn't part of the main exception table. 436 */ 437 offset = (long)&ex->fixup - (pc + LOONGARCH_INSN_SIZE); 438 if (!FIELD_FIT(BPF_FIXUP_OFFSET_MASK, offset)) 439 return -ERANGE; 440 441 ex->type = EX_TYPE_BPF; 442 ex->fixup = FIELD_PREP(BPF_FIXUP_OFFSET_MASK, offset) | FIELD_PREP(BPF_FIXUP_REG_MASK, dst_reg); 443 444 ctx->num_exentries++; 445 446 return 0; 447 } 448 449 static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool extra_pass) 450 { 451 u8 tm = -1; 452 u64 func_addr; 453 bool func_addr_fixed; 454 int i = insn - ctx->prog->insnsi; 455 int ret, jmp_offset; 456 const u8 code = insn->code; 457 const u8 cond = BPF_OP(code); 458 const u8 t1 = LOONGARCH_GPR_T1; 459 const u8 t2 = LOONGARCH_GPR_T2; 460 const u8 src = regmap[insn->src_reg]; 461 const u8 dst = regmap[insn->dst_reg]; 462 const s16 off = insn->off; 463 const s32 imm = insn->imm; 464 const u64 imm64 = (u64)(insn + 1)->imm << 32 | (u32)insn->imm; 465 const bool is32 = BPF_CLASS(insn->code) == BPF_ALU || BPF_CLASS(insn->code) == BPF_JMP32; 466 467 switch (code) { 468 /* dst = src */ 469 case BPF_ALU | BPF_MOV | BPF_X: 470 case BPF_ALU64 | BPF_MOV | BPF_X: 471 move_reg(ctx, dst, src); 472 emit_zext_32(ctx, dst, is32); 473 break; 474 475 /* dst = imm */ 476 case BPF_ALU | BPF_MOV | BPF_K: 477 case BPF_ALU64 | BPF_MOV | BPF_K: 478 move_imm(ctx, dst, imm, is32); 479 break; 480 481 /* dst = dst + src */ 482 case BPF_ALU | BPF_ADD | BPF_X: 483 case BPF_ALU64 | BPF_ADD | BPF_X: 484 emit_insn(ctx, addd, dst, dst, src); 485 emit_zext_32(ctx, dst, is32); 486 break; 487 488 /* dst = dst + imm */ 489 case BPF_ALU | BPF_ADD | BPF_K: 490 case BPF_ALU64 | BPF_ADD | BPF_K: 491 if (is_signed_imm12(imm)) { 492 emit_insn(ctx, addid, dst, dst, imm); 493 } else { 494 move_imm(ctx, t1, imm, is32); 495 emit_insn(ctx, addd, dst, dst, t1); 496 } 497 emit_zext_32(ctx, dst, is32); 498 break; 499 500 /* dst = dst - src */ 501 case BPF_ALU | BPF_SUB | BPF_X: 502 case BPF_ALU64 | BPF_SUB | BPF_X: 503 emit_insn(ctx, subd, dst, dst, src); 504 emit_zext_32(ctx, dst, is32); 505 break; 506 507 /* dst = dst - imm */ 508 case BPF_ALU | BPF_SUB | BPF_K: 509 case BPF_ALU64 | BPF_SUB | BPF_K: 510 if (is_signed_imm12(-imm)) { 511 emit_insn(ctx, addid, dst, dst, -imm); 512 } else { 513 move_imm(ctx, t1, imm, is32); 514 emit_insn(ctx, subd, dst, dst, t1); 515 } 516 emit_zext_32(ctx, dst, is32); 517 break; 518 519 /* dst = dst * src */ 520 case BPF_ALU | BPF_MUL | BPF_X: 521 case BPF_ALU64 | BPF_MUL | BPF_X: 522 emit_insn(ctx, muld, dst, dst, src); 523 emit_zext_32(ctx, dst, is32); 524 break; 525 526 /* dst = dst * imm */ 527 case BPF_ALU | BPF_MUL | BPF_K: 528 case BPF_ALU64 | BPF_MUL | BPF_K: 529 move_imm(ctx, t1, imm, is32); 530 emit_insn(ctx, muld, dst, dst, t1); 531 emit_zext_32(ctx, dst, is32); 532 break; 533 534 /* dst = dst / src */ 535 case BPF_ALU | BPF_DIV | BPF_X: 536 case BPF_ALU64 | BPF_DIV | BPF_X: 537 emit_zext_32(ctx, dst, is32); 538 move_reg(ctx, t1, src); 539 emit_zext_32(ctx, t1, is32); 540 emit_insn(ctx, divdu, dst, dst, t1); 541 emit_zext_32(ctx, dst, is32); 542 break; 543 544 /* dst = dst / imm */ 545 case BPF_ALU | BPF_DIV | BPF_K: 546 case BPF_ALU64 | BPF_DIV | BPF_K: 547 move_imm(ctx, t1, imm, is32); 548 emit_zext_32(ctx, dst, is32); 549 emit_insn(ctx, divdu, dst, dst, t1); 550 emit_zext_32(ctx, dst, is32); 551 break; 552 553 /* dst = dst % src */ 554 case BPF_ALU | BPF_MOD | BPF_X: 555 case BPF_ALU64 | BPF_MOD | BPF_X: 556 emit_zext_32(ctx, dst, is32); 557 move_reg(ctx, t1, src); 558 emit_zext_32(ctx, t1, is32); 559 emit_insn(ctx, moddu, dst, dst, t1); 560 emit_zext_32(ctx, dst, is32); 561 break; 562 563 /* dst = dst % imm */ 564 case BPF_ALU | BPF_MOD | BPF_K: 565 case BPF_ALU64 | BPF_MOD | BPF_K: 566 move_imm(ctx, t1, imm, is32); 567 emit_zext_32(ctx, dst, is32); 568 emit_insn(ctx, moddu, dst, dst, t1); 569 emit_zext_32(ctx, dst, is32); 570 break; 571 572 /* dst = -dst */ 573 case BPF_ALU | BPF_NEG: 574 case BPF_ALU64 | BPF_NEG: 575 move_imm(ctx, t1, imm, is32); 576 emit_insn(ctx, subd, dst, LOONGARCH_GPR_ZERO, dst); 577 emit_zext_32(ctx, dst, is32); 578 break; 579 580 /* dst = dst & src */ 581 case BPF_ALU | BPF_AND | BPF_X: 582 case BPF_ALU64 | BPF_AND | BPF_X: 583 emit_insn(ctx, and, dst, dst, src); 584 emit_zext_32(ctx, dst, is32); 585 break; 586 587 /* dst = dst & imm */ 588 case BPF_ALU | BPF_AND | BPF_K: 589 case BPF_ALU64 | BPF_AND | BPF_K: 590 if (is_unsigned_imm12(imm)) { 591 emit_insn(ctx, andi, dst, dst, imm); 592 } else { 593 move_imm(ctx, t1, imm, is32); 594 emit_insn(ctx, and, dst, dst, t1); 595 } 596 emit_zext_32(ctx, dst, is32); 597 break; 598 599 /* dst = dst | src */ 600 case BPF_ALU | BPF_OR | BPF_X: 601 case BPF_ALU64 | BPF_OR | BPF_X: 602 emit_insn(ctx, or, dst, dst, src); 603 emit_zext_32(ctx, dst, is32); 604 break; 605 606 /* dst = dst | imm */ 607 case BPF_ALU | BPF_OR | BPF_K: 608 case BPF_ALU64 | BPF_OR | BPF_K: 609 if (is_unsigned_imm12(imm)) { 610 emit_insn(ctx, ori, dst, dst, imm); 611 } else { 612 move_imm(ctx, t1, imm, is32); 613 emit_insn(ctx, or, dst, dst, t1); 614 } 615 emit_zext_32(ctx, dst, is32); 616 break; 617 618 /* dst = dst ^ src */ 619 case BPF_ALU | BPF_XOR | BPF_X: 620 case BPF_ALU64 | BPF_XOR | BPF_X: 621 emit_insn(ctx, xor, dst, dst, src); 622 emit_zext_32(ctx, dst, is32); 623 break; 624 625 /* dst = dst ^ imm */ 626 case BPF_ALU | BPF_XOR | BPF_K: 627 case BPF_ALU64 | BPF_XOR | BPF_K: 628 if (is_unsigned_imm12(imm)) { 629 emit_insn(ctx, xori, dst, dst, imm); 630 } else { 631 move_imm(ctx, t1, imm, is32); 632 emit_insn(ctx, xor, dst, dst, t1); 633 } 634 emit_zext_32(ctx, dst, is32); 635 break; 636 637 /* dst = dst << src (logical) */ 638 case BPF_ALU | BPF_LSH | BPF_X: 639 emit_insn(ctx, sllw, dst, dst, src); 640 emit_zext_32(ctx, dst, is32); 641 break; 642 643 case BPF_ALU64 | BPF_LSH | BPF_X: 644 emit_insn(ctx, slld, dst, dst, src); 645 break; 646 647 /* dst = dst << imm (logical) */ 648 case BPF_ALU | BPF_LSH | BPF_K: 649 emit_insn(ctx, slliw, dst, dst, imm); 650 emit_zext_32(ctx, dst, is32); 651 break; 652 653 case BPF_ALU64 | BPF_LSH | BPF_K: 654 emit_insn(ctx, sllid, dst, dst, imm); 655 break; 656 657 /* dst = dst >> src (logical) */ 658 case BPF_ALU | BPF_RSH | BPF_X: 659 emit_insn(ctx, srlw, dst, dst, src); 660 emit_zext_32(ctx, dst, is32); 661 break; 662 663 case BPF_ALU64 | BPF_RSH | BPF_X: 664 emit_insn(ctx, srld, dst, dst, src); 665 break; 666 667 /* dst = dst >> imm (logical) */ 668 case BPF_ALU | BPF_RSH | BPF_K: 669 emit_insn(ctx, srliw, dst, dst, imm); 670 emit_zext_32(ctx, dst, is32); 671 break; 672 673 case BPF_ALU64 | BPF_RSH | BPF_K: 674 emit_insn(ctx, srlid, dst, dst, imm); 675 break; 676 677 /* dst = dst >> src (arithmetic) */ 678 case BPF_ALU | BPF_ARSH | BPF_X: 679 emit_insn(ctx, sraw, dst, dst, src); 680 emit_zext_32(ctx, dst, is32); 681 break; 682 683 case BPF_ALU64 | BPF_ARSH | BPF_X: 684 emit_insn(ctx, srad, dst, dst, src); 685 break; 686 687 /* dst = dst >> imm (arithmetic) */ 688 case BPF_ALU | BPF_ARSH | BPF_K: 689 emit_insn(ctx, sraiw, dst, dst, imm); 690 emit_zext_32(ctx, dst, is32); 691 break; 692 693 case BPF_ALU64 | BPF_ARSH | BPF_K: 694 emit_insn(ctx, sraid, dst, dst, imm); 695 break; 696 697 /* dst = BSWAP##imm(dst) */ 698 case BPF_ALU | BPF_END | BPF_FROM_LE: 699 switch (imm) { 700 case 16: 701 /* zero-extend 16 bits into 64 bits */ 702 emit_insn(ctx, bstrpickd, dst, dst, 15, 0); 703 break; 704 case 32: 705 /* zero-extend 32 bits into 64 bits */ 706 emit_zext_32(ctx, dst, is32); 707 break; 708 case 64: 709 /* do nothing */ 710 break; 711 } 712 break; 713 714 case BPF_ALU | BPF_END | BPF_FROM_BE: 715 switch (imm) { 716 case 16: 717 emit_insn(ctx, revb2h, dst, dst); 718 /* zero-extend 16 bits into 64 bits */ 719 emit_insn(ctx, bstrpickd, dst, dst, 15, 0); 720 break; 721 case 32: 722 emit_insn(ctx, revb2w, dst, dst); 723 /* zero-extend 32 bits into 64 bits */ 724 emit_zext_32(ctx, dst, is32); 725 break; 726 case 64: 727 emit_insn(ctx, revbd, dst, dst); 728 break; 729 } 730 break; 731 732 /* PC += off if dst cond src */ 733 case BPF_JMP | BPF_JEQ | BPF_X: 734 case BPF_JMP | BPF_JNE | BPF_X: 735 case BPF_JMP | BPF_JGT | BPF_X: 736 case BPF_JMP | BPF_JGE | BPF_X: 737 case BPF_JMP | BPF_JLT | BPF_X: 738 case BPF_JMP | BPF_JLE | BPF_X: 739 case BPF_JMP | BPF_JSGT | BPF_X: 740 case BPF_JMP | BPF_JSGE | BPF_X: 741 case BPF_JMP | BPF_JSLT | BPF_X: 742 case BPF_JMP | BPF_JSLE | BPF_X: 743 case BPF_JMP32 | BPF_JEQ | BPF_X: 744 case BPF_JMP32 | BPF_JNE | BPF_X: 745 case BPF_JMP32 | BPF_JGT | BPF_X: 746 case BPF_JMP32 | BPF_JGE | BPF_X: 747 case BPF_JMP32 | BPF_JLT | BPF_X: 748 case BPF_JMP32 | BPF_JLE | BPF_X: 749 case BPF_JMP32 | BPF_JSGT | BPF_X: 750 case BPF_JMP32 | BPF_JSGE | BPF_X: 751 case BPF_JMP32 | BPF_JSLT | BPF_X: 752 case BPF_JMP32 | BPF_JSLE | BPF_X: 753 jmp_offset = bpf2la_offset(i, off, ctx); 754 move_reg(ctx, t1, dst); 755 move_reg(ctx, t2, src); 756 if (is_signed_bpf_cond(BPF_OP(code))) { 757 emit_sext_32(ctx, t1, is32); 758 emit_sext_32(ctx, t2, is32); 759 } else { 760 emit_zext_32(ctx, t1, is32); 761 emit_zext_32(ctx, t2, is32); 762 } 763 if (emit_cond_jmp(ctx, cond, t1, t2, jmp_offset) < 0) 764 goto toofar; 765 break; 766 767 /* PC += off if dst cond imm */ 768 case BPF_JMP | BPF_JEQ | BPF_K: 769 case BPF_JMP | BPF_JNE | BPF_K: 770 case BPF_JMP | BPF_JGT | BPF_K: 771 case BPF_JMP | BPF_JGE | BPF_K: 772 case BPF_JMP | BPF_JLT | BPF_K: 773 case BPF_JMP | BPF_JLE | BPF_K: 774 case BPF_JMP | BPF_JSGT | BPF_K: 775 case BPF_JMP | BPF_JSGE | BPF_K: 776 case BPF_JMP | BPF_JSLT | BPF_K: 777 case BPF_JMP | BPF_JSLE | BPF_K: 778 case BPF_JMP32 | BPF_JEQ | BPF_K: 779 case BPF_JMP32 | BPF_JNE | BPF_K: 780 case BPF_JMP32 | BPF_JGT | BPF_K: 781 case BPF_JMP32 | BPF_JGE | BPF_K: 782 case BPF_JMP32 | BPF_JLT | BPF_K: 783 case BPF_JMP32 | BPF_JLE | BPF_K: 784 case BPF_JMP32 | BPF_JSGT | BPF_K: 785 case BPF_JMP32 | BPF_JSGE | BPF_K: 786 case BPF_JMP32 | BPF_JSLT | BPF_K: 787 case BPF_JMP32 | BPF_JSLE | BPF_K: 788 jmp_offset = bpf2la_offset(i, off, ctx); 789 if (imm) { 790 move_imm(ctx, t1, imm, false); 791 tm = t1; 792 } else { 793 /* If imm is 0, simply use zero register. */ 794 tm = LOONGARCH_GPR_ZERO; 795 } 796 move_reg(ctx, t2, dst); 797 if (is_signed_bpf_cond(BPF_OP(code))) { 798 emit_sext_32(ctx, tm, is32); 799 emit_sext_32(ctx, t2, is32); 800 } else { 801 emit_zext_32(ctx, tm, is32); 802 emit_zext_32(ctx, t2, is32); 803 } 804 if (emit_cond_jmp(ctx, cond, t2, tm, jmp_offset) < 0) 805 goto toofar; 806 break; 807 808 /* PC += off if dst & src */ 809 case BPF_JMP | BPF_JSET | BPF_X: 810 case BPF_JMP32 | BPF_JSET | BPF_X: 811 jmp_offset = bpf2la_offset(i, off, ctx); 812 emit_insn(ctx, and, t1, dst, src); 813 emit_zext_32(ctx, t1, is32); 814 if (emit_cond_jmp(ctx, cond, t1, LOONGARCH_GPR_ZERO, jmp_offset) < 0) 815 goto toofar; 816 break; 817 818 /* PC += off if dst & imm */ 819 case BPF_JMP | BPF_JSET | BPF_K: 820 case BPF_JMP32 | BPF_JSET | BPF_K: 821 jmp_offset = bpf2la_offset(i, off, ctx); 822 move_imm(ctx, t1, imm, is32); 823 emit_insn(ctx, and, t1, dst, t1); 824 emit_zext_32(ctx, t1, is32); 825 if (emit_cond_jmp(ctx, cond, t1, LOONGARCH_GPR_ZERO, jmp_offset) < 0) 826 goto toofar; 827 break; 828 829 /* PC += off */ 830 case BPF_JMP | BPF_JA: 831 jmp_offset = bpf2la_offset(i, off, ctx); 832 if (emit_uncond_jmp(ctx, jmp_offset) < 0) 833 goto toofar; 834 break; 835 836 /* function call */ 837 case BPF_JMP | BPF_CALL: 838 mark_call(ctx); 839 ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass, 840 &func_addr, &func_addr_fixed); 841 if (ret < 0) 842 return ret; 843 844 move_addr(ctx, t1, func_addr); 845 emit_insn(ctx, jirl, t1, LOONGARCH_GPR_RA, 0); 846 move_reg(ctx, regmap[BPF_REG_0], LOONGARCH_GPR_A0); 847 break; 848 849 /* tail call */ 850 case BPF_JMP | BPF_TAIL_CALL: 851 mark_tail_call(ctx); 852 if (emit_bpf_tail_call(ctx) < 0) 853 return -EINVAL; 854 break; 855 856 /* function return */ 857 case BPF_JMP | BPF_EXIT: 858 if (i == ctx->prog->len - 1) 859 break; 860 861 jmp_offset = epilogue_offset(ctx); 862 if (emit_uncond_jmp(ctx, jmp_offset) < 0) 863 goto toofar; 864 break; 865 866 /* dst = imm64 */ 867 case BPF_LD | BPF_IMM | BPF_DW: 868 move_imm(ctx, dst, imm64, is32); 869 return 1; 870 871 /* dst = *(size *)(src + off) */ 872 case BPF_LDX | BPF_MEM | BPF_B: 873 case BPF_LDX | BPF_MEM | BPF_H: 874 case BPF_LDX | BPF_MEM | BPF_W: 875 case BPF_LDX | BPF_MEM | BPF_DW: 876 case BPF_LDX | BPF_PROBE_MEM | BPF_DW: 877 case BPF_LDX | BPF_PROBE_MEM | BPF_W: 878 case BPF_LDX | BPF_PROBE_MEM | BPF_H: 879 case BPF_LDX | BPF_PROBE_MEM | BPF_B: 880 switch (BPF_SIZE(code)) { 881 case BPF_B: 882 if (is_signed_imm12(off)) { 883 emit_insn(ctx, ldbu, dst, src, off); 884 } else { 885 move_imm(ctx, t1, off, is32); 886 emit_insn(ctx, ldxbu, dst, src, t1); 887 } 888 break; 889 case BPF_H: 890 if (is_signed_imm12(off)) { 891 emit_insn(ctx, ldhu, dst, src, off); 892 } else { 893 move_imm(ctx, t1, off, is32); 894 emit_insn(ctx, ldxhu, dst, src, t1); 895 } 896 break; 897 case BPF_W: 898 if (is_signed_imm12(off)) { 899 emit_insn(ctx, ldwu, dst, src, off); 900 } else if (is_signed_imm14(off)) { 901 emit_insn(ctx, ldptrw, dst, src, off); 902 } else { 903 move_imm(ctx, t1, off, is32); 904 emit_insn(ctx, ldxwu, dst, src, t1); 905 } 906 break; 907 case BPF_DW: 908 move_imm(ctx, t1, off, is32); 909 emit_insn(ctx, ldxd, dst, src, t1); 910 break; 911 } 912 913 ret = add_exception_handler(insn, ctx, dst); 914 if (ret) 915 return ret; 916 break; 917 918 /* *(size *)(dst + off) = imm */ 919 case BPF_ST | BPF_MEM | BPF_B: 920 case BPF_ST | BPF_MEM | BPF_H: 921 case BPF_ST | BPF_MEM | BPF_W: 922 case BPF_ST | BPF_MEM | BPF_DW: 923 switch (BPF_SIZE(code)) { 924 case BPF_B: 925 move_imm(ctx, t1, imm, is32); 926 if (is_signed_imm12(off)) { 927 emit_insn(ctx, stb, t1, dst, off); 928 } else { 929 move_imm(ctx, t2, off, is32); 930 emit_insn(ctx, stxb, t1, dst, t2); 931 } 932 break; 933 case BPF_H: 934 move_imm(ctx, t1, imm, is32); 935 if (is_signed_imm12(off)) { 936 emit_insn(ctx, sth, t1, dst, off); 937 } else { 938 move_imm(ctx, t2, off, is32); 939 emit_insn(ctx, stxh, t1, dst, t2); 940 } 941 break; 942 case BPF_W: 943 move_imm(ctx, t1, imm, is32); 944 if (is_signed_imm12(off)) { 945 emit_insn(ctx, stw, t1, dst, off); 946 } else if (is_signed_imm14(off)) { 947 emit_insn(ctx, stptrw, t1, dst, off); 948 } else { 949 move_imm(ctx, t2, off, is32); 950 emit_insn(ctx, stxw, t1, dst, t2); 951 } 952 break; 953 case BPF_DW: 954 move_imm(ctx, t1, imm, is32); 955 if (is_signed_imm12(off)) { 956 emit_insn(ctx, std, t1, dst, off); 957 } else if (is_signed_imm14(off)) { 958 emit_insn(ctx, stptrd, t1, dst, off); 959 } else { 960 move_imm(ctx, t2, off, is32); 961 emit_insn(ctx, stxd, t1, dst, t2); 962 } 963 break; 964 } 965 break; 966 967 /* *(size *)(dst + off) = src */ 968 case BPF_STX | BPF_MEM | BPF_B: 969 case BPF_STX | BPF_MEM | BPF_H: 970 case BPF_STX | BPF_MEM | BPF_W: 971 case BPF_STX | BPF_MEM | BPF_DW: 972 switch (BPF_SIZE(code)) { 973 case BPF_B: 974 if (is_signed_imm12(off)) { 975 emit_insn(ctx, stb, src, dst, off); 976 } else { 977 move_imm(ctx, t1, off, is32); 978 emit_insn(ctx, stxb, src, dst, t1); 979 } 980 break; 981 case BPF_H: 982 if (is_signed_imm12(off)) { 983 emit_insn(ctx, sth, src, dst, off); 984 } else { 985 move_imm(ctx, t1, off, is32); 986 emit_insn(ctx, stxh, src, dst, t1); 987 } 988 break; 989 case BPF_W: 990 if (is_signed_imm12(off)) { 991 emit_insn(ctx, stw, src, dst, off); 992 } else if (is_signed_imm14(off)) { 993 emit_insn(ctx, stptrw, src, dst, off); 994 } else { 995 move_imm(ctx, t1, off, is32); 996 emit_insn(ctx, stxw, src, dst, t1); 997 } 998 break; 999 case BPF_DW: 1000 if (is_signed_imm12(off)) { 1001 emit_insn(ctx, std, src, dst, off); 1002 } else if (is_signed_imm14(off)) { 1003 emit_insn(ctx, stptrd, src, dst, off); 1004 } else { 1005 move_imm(ctx, t1, off, is32); 1006 emit_insn(ctx, stxd, src, dst, t1); 1007 } 1008 break; 1009 } 1010 break; 1011 1012 case BPF_STX | BPF_ATOMIC | BPF_W: 1013 case BPF_STX | BPF_ATOMIC | BPF_DW: 1014 emit_atomic(insn, ctx); 1015 break; 1016 1017 /* Speculation barrier */ 1018 case BPF_ST | BPF_NOSPEC: 1019 break; 1020 1021 default: 1022 pr_err("bpf_jit: unknown opcode %02x\n", code); 1023 return -EINVAL; 1024 } 1025 1026 return 0; 1027 1028 toofar: 1029 pr_info_once("bpf_jit: opcode %02x, jump too far\n", code); 1030 return -E2BIG; 1031 } 1032 1033 static int build_body(struct jit_ctx *ctx, bool extra_pass) 1034 { 1035 int i; 1036 const struct bpf_prog *prog = ctx->prog; 1037 1038 for (i = 0; i < prog->len; i++) { 1039 const struct bpf_insn *insn = &prog->insnsi[i]; 1040 int ret; 1041 1042 if (ctx->image == NULL) 1043 ctx->offset[i] = ctx->idx; 1044 1045 ret = build_insn(insn, ctx, extra_pass); 1046 if (ret > 0) { 1047 i++; 1048 if (ctx->image == NULL) 1049 ctx->offset[i] = ctx->idx; 1050 continue; 1051 } 1052 if (ret) 1053 return ret; 1054 } 1055 1056 if (ctx->image == NULL) 1057 ctx->offset[i] = ctx->idx; 1058 1059 return 0; 1060 } 1061 1062 /* Fill space with break instructions */ 1063 static void jit_fill_hole(void *area, unsigned int size) 1064 { 1065 u32 *ptr; 1066 1067 /* We are guaranteed to have aligned memory */ 1068 for (ptr = area; size >= sizeof(u32); size -= sizeof(u32)) 1069 *ptr++ = INSN_BREAK; 1070 } 1071 1072 static int validate_code(struct jit_ctx *ctx) 1073 { 1074 int i; 1075 union loongarch_instruction insn; 1076 1077 for (i = 0; i < ctx->idx; i++) { 1078 insn = ctx->image[i]; 1079 /* Check INSN_BREAK */ 1080 if (insn.word == INSN_BREAK) 1081 return -1; 1082 } 1083 1084 if (WARN_ON_ONCE(ctx->num_exentries != ctx->prog->aux->num_exentries)) 1085 return -1; 1086 1087 return 0; 1088 } 1089 1090 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) 1091 { 1092 bool tmp_blinded = false, extra_pass = false; 1093 u8 *image_ptr; 1094 int image_size, prog_size, extable_size; 1095 struct jit_ctx ctx; 1096 struct jit_data *jit_data; 1097 struct bpf_binary_header *header; 1098 struct bpf_prog *tmp, *orig_prog = prog; 1099 1100 /* 1101 * If BPF JIT was not enabled then we must fall back to 1102 * the interpreter. 1103 */ 1104 if (!prog->jit_requested) 1105 return orig_prog; 1106 1107 tmp = bpf_jit_blind_constants(prog); 1108 /* 1109 * If blinding was requested and we failed during blinding, 1110 * we must fall back to the interpreter. Otherwise, we save 1111 * the new JITed code. 1112 */ 1113 if (IS_ERR(tmp)) 1114 return orig_prog; 1115 1116 if (tmp != prog) { 1117 tmp_blinded = true; 1118 prog = tmp; 1119 } 1120 1121 jit_data = prog->aux->jit_data; 1122 if (!jit_data) { 1123 jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL); 1124 if (!jit_data) { 1125 prog = orig_prog; 1126 goto out; 1127 } 1128 prog->aux->jit_data = jit_data; 1129 } 1130 if (jit_data->ctx.offset) { 1131 ctx = jit_data->ctx; 1132 image_ptr = jit_data->image; 1133 header = jit_data->header; 1134 extra_pass = true; 1135 prog_size = sizeof(u32) * ctx.idx; 1136 goto skip_init_ctx; 1137 } 1138 1139 memset(&ctx, 0, sizeof(ctx)); 1140 ctx.prog = prog; 1141 1142 ctx.offset = kvcalloc(prog->len + 1, sizeof(u32), GFP_KERNEL); 1143 if (ctx.offset == NULL) { 1144 prog = orig_prog; 1145 goto out_offset; 1146 } 1147 1148 /* 1. Initial fake pass to compute ctx->idx and set ctx->flags */ 1149 build_prologue(&ctx); 1150 if (build_body(&ctx, extra_pass)) { 1151 prog = orig_prog; 1152 goto out_offset; 1153 } 1154 ctx.epilogue_offset = ctx.idx; 1155 build_epilogue(&ctx); 1156 1157 extable_size = prog->aux->num_exentries * sizeof(struct exception_table_entry); 1158 1159 /* Now we know the actual image size. 1160 * As each LoongArch instruction is of length 32bit, 1161 * we are translating number of JITed intructions into 1162 * the size required to store these JITed code. 1163 */ 1164 prog_size = sizeof(u32) * ctx.idx; 1165 image_size = prog_size + extable_size; 1166 /* Now we know the size of the structure to make */ 1167 header = bpf_jit_binary_alloc(image_size, &image_ptr, 1168 sizeof(u32), jit_fill_hole); 1169 if (header == NULL) { 1170 prog = orig_prog; 1171 goto out_offset; 1172 } 1173 1174 /* 2. Now, the actual pass to generate final JIT code */ 1175 ctx.image = (union loongarch_instruction *)image_ptr; 1176 if (extable_size) 1177 prog->aux->extable = (void *)image_ptr + prog_size; 1178 1179 skip_init_ctx: 1180 ctx.idx = 0; 1181 ctx.num_exentries = 0; 1182 1183 build_prologue(&ctx); 1184 if (build_body(&ctx, extra_pass)) { 1185 bpf_jit_binary_free(header); 1186 prog = orig_prog; 1187 goto out_offset; 1188 } 1189 build_epilogue(&ctx); 1190 1191 /* 3. Extra pass to validate JITed code */ 1192 if (validate_code(&ctx)) { 1193 bpf_jit_binary_free(header); 1194 prog = orig_prog; 1195 goto out_offset; 1196 } 1197 1198 /* And we're done */ 1199 if (bpf_jit_enable > 1) 1200 bpf_jit_dump(prog->len, prog_size, 2, ctx.image); 1201 1202 /* Update the icache */ 1203 flush_icache_range((unsigned long)header, (unsigned long)(ctx.image + ctx.idx)); 1204 1205 if (!prog->is_func || extra_pass) { 1206 if (extra_pass && ctx.idx != jit_data->ctx.idx) { 1207 pr_err_once("multi-func JIT bug %d != %d\n", 1208 ctx.idx, jit_data->ctx.idx); 1209 bpf_jit_binary_free(header); 1210 prog->bpf_func = NULL; 1211 prog->jited = 0; 1212 prog->jited_len = 0; 1213 goto out_offset; 1214 } 1215 bpf_jit_binary_lock_ro(header); 1216 } else { 1217 jit_data->ctx = ctx; 1218 jit_data->image = image_ptr; 1219 jit_data->header = header; 1220 } 1221 prog->jited = 1; 1222 prog->jited_len = prog_size; 1223 prog->bpf_func = (void *)ctx.image; 1224 1225 if (!prog->is_func || extra_pass) { 1226 int i; 1227 1228 /* offset[prog->len] is the size of program */ 1229 for (i = 0; i <= prog->len; i++) 1230 ctx.offset[i] *= LOONGARCH_INSN_SIZE; 1231 bpf_prog_fill_jited_linfo(prog, ctx.offset + 1); 1232 1233 out_offset: 1234 kvfree(ctx.offset); 1235 kfree(jit_data); 1236 prog->aux->jit_data = NULL; 1237 } 1238 1239 out: 1240 if (tmp_blinded) 1241 bpf_jit_prog_release_other(prog, prog == orig_prog ? tmp : orig_prog); 1242 1243 out_offset = -1; 1244 1245 return prog; 1246 } 1247 1248 /* Indicate the JIT backend supports mixing bpf2bpf and tailcalls. */ 1249 bool bpf_jit_supports_subprog_tailcalls(void) 1250 { 1251 return true; 1252 } 1253