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 bool is32 = BPF_CLASS(insn->code) == BPF_ALU || BPF_CLASS(insn->code) == BPF_JMP32; 465 466 switch (code) { 467 /* dst = src */ 468 case BPF_ALU | BPF_MOV | BPF_X: 469 case BPF_ALU64 | BPF_MOV | BPF_X: 470 move_reg(ctx, dst, src); 471 emit_zext_32(ctx, dst, is32); 472 break; 473 474 /* dst = imm */ 475 case BPF_ALU | BPF_MOV | BPF_K: 476 case BPF_ALU64 | BPF_MOV | BPF_K: 477 move_imm(ctx, dst, imm, is32); 478 break; 479 480 /* dst = dst + src */ 481 case BPF_ALU | BPF_ADD | BPF_X: 482 case BPF_ALU64 | BPF_ADD | BPF_X: 483 emit_insn(ctx, addd, dst, dst, src); 484 emit_zext_32(ctx, dst, is32); 485 break; 486 487 /* dst = dst + imm */ 488 case BPF_ALU | BPF_ADD | BPF_K: 489 case BPF_ALU64 | BPF_ADD | BPF_K: 490 if (is_signed_imm12(imm)) { 491 emit_insn(ctx, addid, dst, dst, imm); 492 } else { 493 move_imm(ctx, t1, imm, is32); 494 emit_insn(ctx, addd, dst, dst, t1); 495 } 496 emit_zext_32(ctx, dst, is32); 497 break; 498 499 /* dst = dst - src */ 500 case BPF_ALU | BPF_SUB | BPF_X: 501 case BPF_ALU64 | BPF_SUB | BPF_X: 502 emit_insn(ctx, subd, dst, dst, src); 503 emit_zext_32(ctx, dst, is32); 504 break; 505 506 /* dst = dst - imm */ 507 case BPF_ALU | BPF_SUB | BPF_K: 508 case BPF_ALU64 | BPF_SUB | BPF_K: 509 if (is_signed_imm12(-imm)) { 510 emit_insn(ctx, addid, dst, dst, -imm); 511 } else { 512 move_imm(ctx, t1, imm, is32); 513 emit_insn(ctx, subd, dst, dst, t1); 514 } 515 emit_zext_32(ctx, dst, is32); 516 break; 517 518 /* dst = dst * src */ 519 case BPF_ALU | BPF_MUL | BPF_X: 520 case BPF_ALU64 | BPF_MUL | BPF_X: 521 emit_insn(ctx, muld, dst, dst, src); 522 emit_zext_32(ctx, dst, is32); 523 break; 524 525 /* dst = dst * imm */ 526 case BPF_ALU | BPF_MUL | BPF_K: 527 case BPF_ALU64 | BPF_MUL | BPF_K: 528 move_imm(ctx, t1, imm, is32); 529 emit_insn(ctx, muld, dst, dst, t1); 530 emit_zext_32(ctx, dst, is32); 531 break; 532 533 /* dst = dst / src */ 534 case BPF_ALU | BPF_DIV | BPF_X: 535 case BPF_ALU64 | BPF_DIV | BPF_X: 536 emit_zext_32(ctx, dst, is32); 537 move_reg(ctx, t1, src); 538 emit_zext_32(ctx, t1, is32); 539 emit_insn(ctx, divdu, dst, dst, t1); 540 emit_zext_32(ctx, dst, is32); 541 break; 542 543 /* dst = dst / imm */ 544 case BPF_ALU | BPF_DIV | BPF_K: 545 case BPF_ALU64 | BPF_DIV | BPF_K: 546 move_imm(ctx, t1, imm, is32); 547 emit_zext_32(ctx, dst, is32); 548 emit_insn(ctx, divdu, dst, dst, t1); 549 emit_zext_32(ctx, dst, is32); 550 break; 551 552 /* dst = dst % src */ 553 case BPF_ALU | BPF_MOD | BPF_X: 554 case BPF_ALU64 | BPF_MOD | BPF_X: 555 emit_zext_32(ctx, dst, is32); 556 move_reg(ctx, t1, src); 557 emit_zext_32(ctx, t1, is32); 558 emit_insn(ctx, moddu, dst, dst, t1); 559 emit_zext_32(ctx, dst, is32); 560 break; 561 562 /* dst = dst % imm */ 563 case BPF_ALU | BPF_MOD | BPF_K: 564 case BPF_ALU64 | BPF_MOD | BPF_K: 565 move_imm(ctx, t1, imm, is32); 566 emit_zext_32(ctx, dst, is32); 567 emit_insn(ctx, moddu, dst, dst, t1); 568 emit_zext_32(ctx, dst, is32); 569 break; 570 571 /* dst = -dst */ 572 case BPF_ALU | BPF_NEG: 573 case BPF_ALU64 | BPF_NEG: 574 move_imm(ctx, t1, imm, is32); 575 emit_insn(ctx, subd, dst, LOONGARCH_GPR_ZERO, dst); 576 emit_zext_32(ctx, dst, is32); 577 break; 578 579 /* dst = dst & src */ 580 case BPF_ALU | BPF_AND | BPF_X: 581 case BPF_ALU64 | BPF_AND | BPF_X: 582 emit_insn(ctx, and, dst, dst, src); 583 emit_zext_32(ctx, dst, is32); 584 break; 585 586 /* dst = dst & imm */ 587 case BPF_ALU | BPF_AND | BPF_K: 588 case BPF_ALU64 | BPF_AND | BPF_K: 589 if (is_unsigned_imm12(imm)) { 590 emit_insn(ctx, andi, dst, dst, imm); 591 } else { 592 move_imm(ctx, t1, imm, is32); 593 emit_insn(ctx, and, dst, dst, t1); 594 } 595 emit_zext_32(ctx, dst, is32); 596 break; 597 598 /* dst = dst | src */ 599 case BPF_ALU | BPF_OR | BPF_X: 600 case BPF_ALU64 | BPF_OR | BPF_X: 601 emit_insn(ctx, or, dst, dst, src); 602 emit_zext_32(ctx, dst, is32); 603 break; 604 605 /* dst = dst | imm */ 606 case BPF_ALU | BPF_OR | BPF_K: 607 case BPF_ALU64 | BPF_OR | BPF_K: 608 if (is_unsigned_imm12(imm)) { 609 emit_insn(ctx, ori, dst, dst, imm); 610 } else { 611 move_imm(ctx, t1, imm, is32); 612 emit_insn(ctx, or, dst, dst, t1); 613 } 614 emit_zext_32(ctx, dst, is32); 615 break; 616 617 /* dst = dst ^ src */ 618 case BPF_ALU | BPF_XOR | BPF_X: 619 case BPF_ALU64 | BPF_XOR | BPF_X: 620 emit_insn(ctx, xor, dst, dst, src); 621 emit_zext_32(ctx, dst, is32); 622 break; 623 624 /* dst = dst ^ imm */ 625 case BPF_ALU | BPF_XOR | BPF_K: 626 case BPF_ALU64 | BPF_XOR | BPF_K: 627 if (is_unsigned_imm12(imm)) { 628 emit_insn(ctx, xori, dst, dst, imm); 629 } else { 630 move_imm(ctx, t1, imm, is32); 631 emit_insn(ctx, xor, dst, dst, t1); 632 } 633 emit_zext_32(ctx, dst, is32); 634 break; 635 636 /* dst = dst << src (logical) */ 637 case BPF_ALU | BPF_LSH | BPF_X: 638 emit_insn(ctx, sllw, dst, dst, src); 639 emit_zext_32(ctx, dst, is32); 640 break; 641 642 case BPF_ALU64 | BPF_LSH | BPF_X: 643 emit_insn(ctx, slld, dst, dst, src); 644 break; 645 646 /* dst = dst << imm (logical) */ 647 case BPF_ALU | BPF_LSH | BPF_K: 648 emit_insn(ctx, slliw, dst, dst, imm); 649 emit_zext_32(ctx, dst, is32); 650 break; 651 652 case BPF_ALU64 | BPF_LSH | BPF_K: 653 emit_insn(ctx, sllid, dst, dst, imm); 654 break; 655 656 /* dst = dst >> src (logical) */ 657 case BPF_ALU | BPF_RSH | BPF_X: 658 emit_insn(ctx, srlw, dst, dst, src); 659 emit_zext_32(ctx, dst, is32); 660 break; 661 662 case BPF_ALU64 | BPF_RSH | BPF_X: 663 emit_insn(ctx, srld, dst, dst, src); 664 break; 665 666 /* dst = dst >> imm (logical) */ 667 case BPF_ALU | BPF_RSH | BPF_K: 668 emit_insn(ctx, srliw, dst, dst, imm); 669 emit_zext_32(ctx, dst, is32); 670 break; 671 672 case BPF_ALU64 | BPF_RSH | BPF_K: 673 emit_insn(ctx, srlid, dst, dst, imm); 674 break; 675 676 /* dst = dst >> src (arithmetic) */ 677 case BPF_ALU | BPF_ARSH | BPF_X: 678 emit_insn(ctx, sraw, dst, dst, src); 679 emit_zext_32(ctx, dst, is32); 680 break; 681 682 case BPF_ALU64 | BPF_ARSH | BPF_X: 683 emit_insn(ctx, srad, dst, dst, src); 684 break; 685 686 /* dst = dst >> imm (arithmetic) */ 687 case BPF_ALU | BPF_ARSH | BPF_K: 688 emit_insn(ctx, sraiw, dst, dst, imm); 689 emit_zext_32(ctx, dst, is32); 690 break; 691 692 case BPF_ALU64 | BPF_ARSH | BPF_K: 693 emit_insn(ctx, sraid, dst, dst, imm); 694 break; 695 696 /* dst = BSWAP##imm(dst) */ 697 case BPF_ALU | BPF_END | BPF_FROM_LE: 698 switch (imm) { 699 case 16: 700 /* zero-extend 16 bits into 64 bits */ 701 emit_insn(ctx, bstrpickd, dst, dst, 15, 0); 702 break; 703 case 32: 704 /* zero-extend 32 bits into 64 bits */ 705 emit_zext_32(ctx, dst, is32); 706 break; 707 case 64: 708 /* do nothing */ 709 break; 710 } 711 break; 712 713 case BPF_ALU | BPF_END | BPF_FROM_BE: 714 switch (imm) { 715 case 16: 716 emit_insn(ctx, revb2h, dst, dst); 717 /* zero-extend 16 bits into 64 bits */ 718 emit_insn(ctx, bstrpickd, dst, dst, 15, 0); 719 break; 720 case 32: 721 emit_insn(ctx, revb2w, dst, dst); 722 /* zero-extend 32 bits into 64 bits */ 723 emit_zext_32(ctx, dst, is32); 724 break; 725 case 64: 726 emit_insn(ctx, revbd, dst, dst); 727 break; 728 } 729 break; 730 731 /* PC += off if dst cond src */ 732 case BPF_JMP | BPF_JEQ | BPF_X: 733 case BPF_JMP | BPF_JNE | BPF_X: 734 case BPF_JMP | BPF_JGT | BPF_X: 735 case BPF_JMP | BPF_JGE | BPF_X: 736 case BPF_JMP | BPF_JLT | BPF_X: 737 case BPF_JMP | BPF_JLE | BPF_X: 738 case BPF_JMP | BPF_JSGT | BPF_X: 739 case BPF_JMP | BPF_JSGE | BPF_X: 740 case BPF_JMP | BPF_JSLT | BPF_X: 741 case BPF_JMP | BPF_JSLE | BPF_X: 742 case BPF_JMP32 | BPF_JEQ | BPF_X: 743 case BPF_JMP32 | BPF_JNE | BPF_X: 744 case BPF_JMP32 | BPF_JGT | BPF_X: 745 case BPF_JMP32 | BPF_JGE | BPF_X: 746 case BPF_JMP32 | BPF_JLT | BPF_X: 747 case BPF_JMP32 | BPF_JLE | BPF_X: 748 case BPF_JMP32 | BPF_JSGT | BPF_X: 749 case BPF_JMP32 | BPF_JSGE | BPF_X: 750 case BPF_JMP32 | BPF_JSLT | BPF_X: 751 case BPF_JMP32 | BPF_JSLE | BPF_X: 752 jmp_offset = bpf2la_offset(i, off, ctx); 753 move_reg(ctx, t1, dst); 754 move_reg(ctx, t2, src); 755 if (is_signed_bpf_cond(BPF_OP(code))) { 756 emit_sext_32(ctx, t1, is32); 757 emit_sext_32(ctx, t2, is32); 758 } else { 759 emit_zext_32(ctx, t1, is32); 760 emit_zext_32(ctx, t2, is32); 761 } 762 if (emit_cond_jmp(ctx, cond, t1, t2, jmp_offset) < 0) 763 goto toofar; 764 break; 765 766 /* PC += off if dst cond imm */ 767 case BPF_JMP | BPF_JEQ | BPF_K: 768 case BPF_JMP | BPF_JNE | BPF_K: 769 case BPF_JMP | BPF_JGT | BPF_K: 770 case BPF_JMP | BPF_JGE | BPF_K: 771 case BPF_JMP | BPF_JLT | BPF_K: 772 case BPF_JMP | BPF_JLE | BPF_K: 773 case BPF_JMP | BPF_JSGT | BPF_K: 774 case BPF_JMP | BPF_JSGE | BPF_K: 775 case BPF_JMP | BPF_JSLT | BPF_K: 776 case BPF_JMP | BPF_JSLE | BPF_K: 777 case BPF_JMP32 | BPF_JEQ | BPF_K: 778 case BPF_JMP32 | BPF_JNE | BPF_K: 779 case BPF_JMP32 | BPF_JGT | BPF_K: 780 case BPF_JMP32 | BPF_JGE | BPF_K: 781 case BPF_JMP32 | BPF_JLT | BPF_K: 782 case BPF_JMP32 | BPF_JLE | BPF_K: 783 case BPF_JMP32 | BPF_JSGT | BPF_K: 784 case BPF_JMP32 | BPF_JSGE | BPF_K: 785 case BPF_JMP32 | BPF_JSLT | BPF_K: 786 case BPF_JMP32 | BPF_JSLE | BPF_K: 787 jmp_offset = bpf2la_offset(i, off, ctx); 788 if (imm) { 789 move_imm(ctx, t1, imm, false); 790 tm = t1; 791 } else { 792 /* If imm is 0, simply use zero register. */ 793 tm = LOONGARCH_GPR_ZERO; 794 } 795 move_reg(ctx, t2, dst); 796 if (is_signed_bpf_cond(BPF_OP(code))) { 797 emit_sext_32(ctx, tm, is32); 798 emit_sext_32(ctx, t2, is32); 799 } else { 800 emit_zext_32(ctx, tm, is32); 801 emit_zext_32(ctx, t2, is32); 802 } 803 if (emit_cond_jmp(ctx, cond, t2, tm, jmp_offset) < 0) 804 goto toofar; 805 break; 806 807 /* PC += off if dst & src */ 808 case BPF_JMP | BPF_JSET | BPF_X: 809 case BPF_JMP32 | BPF_JSET | BPF_X: 810 jmp_offset = bpf2la_offset(i, off, ctx); 811 emit_insn(ctx, and, t1, dst, src); 812 emit_zext_32(ctx, t1, is32); 813 if (emit_cond_jmp(ctx, cond, t1, LOONGARCH_GPR_ZERO, jmp_offset) < 0) 814 goto toofar; 815 break; 816 817 /* PC += off if dst & imm */ 818 case BPF_JMP | BPF_JSET | BPF_K: 819 case BPF_JMP32 | BPF_JSET | BPF_K: 820 jmp_offset = bpf2la_offset(i, off, ctx); 821 move_imm(ctx, t1, imm, is32); 822 emit_insn(ctx, and, t1, dst, t1); 823 emit_zext_32(ctx, t1, is32); 824 if (emit_cond_jmp(ctx, cond, t1, LOONGARCH_GPR_ZERO, jmp_offset) < 0) 825 goto toofar; 826 break; 827 828 /* PC += off */ 829 case BPF_JMP | BPF_JA: 830 jmp_offset = bpf2la_offset(i, off, ctx); 831 if (emit_uncond_jmp(ctx, jmp_offset) < 0) 832 goto toofar; 833 break; 834 835 /* function call */ 836 case BPF_JMP | BPF_CALL: 837 mark_call(ctx); 838 ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass, 839 &func_addr, &func_addr_fixed); 840 if (ret < 0) 841 return ret; 842 843 move_addr(ctx, t1, func_addr); 844 emit_insn(ctx, jirl, t1, LOONGARCH_GPR_RA, 0); 845 move_reg(ctx, regmap[BPF_REG_0], LOONGARCH_GPR_A0); 846 break; 847 848 /* tail call */ 849 case BPF_JMP | BPF_TAIL_CALL: 850 mark_tail_call(ctx); 851 if (emit_bpf_tail_call(ctx) < 0) 852 return -EINVAL; 853 break; 854 855 /* function return */ 856 case BPF_JMP | BPF_EXIT: 857 if (i == ctx->prog->len - 1) 858 break; 859 860 jmp_offset = epilogue_offset(ctx); 861 if (emit_uncond_jmp(ctx, jmp_offset) < 0) 862 goto toofar; 863 break; 864 865 /* dst = imm64 */ 866 case BPF_LD | BPF_IMM | BPF_DW: 867 { 868 const u64 imm64 = (u64)(insn + 1)->imm << 32 | (u32)insn->imm; 869 870 move_imm(ctx, dst, imm64, is32); 871 return 1; 872 } 873 874 /* dst = *(size *)(src + off) */ 875 case BPF_LDX | BPF_MEM | BPF_B: 876 case BPF_LDX | BPF_MEM | BPF_H: 877 case BPF_LDX | BPF_MEM | BPF_W: 878 case BPF_LDX | BPF_MEM | BPF_DW: 879 case BPF_LDX | BPF_PROBE_MEM | BPF_DW: 880 case BPF_LDX | BPF_PROBE_MEM | BPF_W: 881 case BPF_LDX | BPF_PROBE_MEM | BPF_H: 882 case BPF_LDX | BPF_PROBE_MEM | BPF_B: 883 switch (BPF_SIZE(code)) { 884 case BPF_B: 885 if (is_signed_imm12(off)) { 886 emit_insn(ctx, ldbu, dst, src, off); 887 } else { 888 move_imm(ctx, t1, off, is32); 889 emit_insn(ctx, ldxbu, dst, src, t1); 890 } 891 break; 892 case BPF_H: 893 if (is_signed_imm12(off)) { 894 emit_insn(ctx, ldhu, dst, src, off); 895 } else { 896 move_imm(ctx, t1, off, is32); 897 emit_insn(ctx, ldxhu, dst, src, t1); 898 } 899 break; 900 case BPF_W: 901 if (is_signed_imm12(off)) { 902 emit_insn(ctx, ldwu, dst, src, off); 903 } else if (is_signed_imm14(off)) { 904 emit_insn(ctx, ldptrw, dst, src, off); 905 } else { 906 move_imm(ctx, t1, off, is32); 907 emit_insn(ctx, ldxwu, dst, src, t1); 908 } 909 break; 910 case BPF_DW: 911 move_imm(ctx, t1, off, is32); 912 emit_insn(ctx, ldxd, dst, src, t1); 913 break; 914 } 915 916 ret = add_exception_handler(insn, ctx, dst); 917 if (ret) 918 return ret; 919 break; 920 921 /* *(size *)(dst + off) = imm */ 922 case BPF_ST | BPF_MEM | BPF_B: 923 case BPF_ST | BPF_MEM | BPF_H: 924 case BPF_ST | BPF_MEM | BPF_W: 925 case BPF_ST | BPF_MEM | BPF_DW: 926 switch (BPF_SIZE(code)) { 927 case BPF_B: 928 move_imm(ctx, t1, imm, is32); 929 if (is_signed_imm12(off)) { 930 emit_insn(ctx, stb, t1, dst, off); 931 } else { 932 move_imm(ctx, t2, off, is32); 933 emit_insn(ctx, stxb, t1, dst, t2); 934 } 935 break; 936 case BPF_H: 937 move_imm(ctx, t1, imm, is32); 938 if (is_signed_imm12(off)) { 939 emit_insn(ctx, sth, t1, dst, off); 940 } else { 941 move_imm(ctx, t2, off, is32); 942 emit_insn(ctx, stxh, t1, dst, t2); 943 } 944 break; 945 case BPF_W: 946 move_imm(ctx, t1, imm, is32); 947 if (is_signed_imm12(off)) { 948 emit_insn(ctx, stw, t1, dst, off); 949 } else if (is_signed_imm14(off)) { 950 emit_insn(ctx, stptrw, t1, dst, off); 951 } else { 952 move_imm(ctx, t2, off, is32); 953 emit_insn(ctx, stxw, t1, dst, t2); 954 } 955 break; 956 case BPF_DW: 957 move_imm(ctx, t1, imm, is32); 958 if (is_signed_imm12(off)) { 959 emit_insn(ctx, std, t1, dst, off); 960 } else if (is_signed_imm14(off)) { 961 emit_insn(ctx, stptrd, t1, dst, off); 962 } else { 963 move_imm(ctx, t2, off, is32); 964 emit_insn(ctx, stxd, t1, dst, t2); 965 } 966 break; 967 } 968 break; 969 970 /* *(size *)(dst + off) = src */ 971 case BPF_STX | BPF_MEM | BPF_B: 972 case BPF_STX | BPF_MEM | BPF_H: 973 case BPF_STX | BPF_MEM | BPF_W: 974 case BPF_STX | BPF_MEM | BPF_DW: 975 switch (BPF_SIZE(code)) { 976 case BPF_B: 977 if (is_signed_imm12(off)) { 978 emit_insn(ctx, stb, src, dst, off); 979 } else { 980 move_imm(ctx, t1, off, is32); 981 emit_insn(ctx, stxb, src, dst, t1); 982 } 983 break; 984 case BPF_H: 985 if (is_signed_imm12(off)) { 986 emit_insn(ctx, sth, src, dst, off); 987 } else { 988 move_imm(ctx, t1, off, is32); 989 emit_insn(ctx, stxh, src, dst, t1); 990 } 991 break; 992 case BPF_W: 993 if (is_signed_imm12(off)) { 994 emit_insn(ctx, stw, src, dst, off); 995 } else if (is_signed_imm14(off)) { 996 emit_insn(ctx, stptrw, src, dst, off); 997 } else { 998 move_imm(ctx, t1, off, is32); 999 emit_insn(ctx, stxw, src, dst, t1); 1000 } 1001 break; 1002 case BPF_DW: 1003 if (is_signed_imm12(off)) { 1004 emit_insn(ctx, std, src, dst, off); 1005 } else if (is_signed_imm14(off)) { 1006 emit_insn(ctx, stptrd, src, dst, off); 1007 } else { 1008 move_imm(ctx, t1, off, is32); 1009 emit_insn(ctx, stxd, src, dst, t1); 1010 } 1011 break; 1012 } 1013 break; 1014 1015 case BPF_STX | BPF_ATOMIC | BPF_W: 1016 case BPF_STX | BPF_ATOMIC | BPF_DW: 1017 emit_atomic(insn, ctx); 1018 break; 1019 1020 /* Speculation barrier */ 1021 case BPF_ST | BPF_NOSPEC: 1022 break; 1023 1024 default: 1025 pr_err("bpf_jit: unknown opcode %02x\n", code); 1026 return -EINVAL; 1027 } 1028 1029 return 0; 1030 1031 toofar: 1032 pr_info_once("bpf_jit: opcode %02x, jump too far\n", code); 1033 return -E2BIG; 1034 } 1035 1036 static int build_body(struct jit_ctx *ctx, bool extra_pass) 1037 { 1038 int i; 1039 const struct bpf_prog *prog = ctx->prog; 1040 1041 for (i = 0; i < prog->len; i++) { 1042 const struct bpf_insn *insn = &prog->insnsi[i]; 1043 int ret; 1044 1045 if (ctx->image == NULL) 1046 ctx->offset[i] = ctx->idx; 1047 1048 ret = build_insn(insn, ctx, extra_pass); 1049 if (ret > 0) { 1050 i++; 1051 if (ctx->image == NULL) 1052 ctx->offset[i] = ctx->idx; 1053 continue; 1054 } 1055 if (ret) 1056 return ret; 1057 } 1058 1059 if (ctx->image == NULL) 1060 ctx->offset[i] = ctx->idx; 1061 1062 return 0; 1063 } 1064 1065 /* Fill space with break instructions */ 1066 static void jit_fill_hole(void *area, unsigned int size) 1067 { 1068 u32 *ptr; 1069 1070 /* We are guaranteed to have aligned memory */ 1071 for (ptr = area; size >= sizeof(u32); size -= sizeof(u32)) 1072 *ptr++ = INSN_BREAK; 1073 } 1074 1075 static int validate_code(struct jit_ctx *ctx) 1076 { 1077 int i; 1078 union loongarch_instruction insn; 1079 1080 for (i = 0; i < ctx->idx; i++) { 1081 insn = ctx->image[i]; 1082 /* Check INSN_BREAK */ 1083 if (insn.word == INSN_BREAK) 1084 return -1; 1085 } 1086 1087 if (WARN_ON_ONCE(ctx->num_exentries != ctx->prog->aux->num_exentries)) 1088 return -1; 1089 1090 return 0; 1091 } 1092 1093 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) 1094 { 1095 bool tmp_blinded = false, extra_pass = false; 1096 u8 *image_ptr; 1097 int image_size, prog_size, extable_size; 1098 struct jit_ctx ctx; 1099 struct jit_data *jit_data; 1100 struct bpf_binary_header *header; 1101 struct bpf_prog *tmp, *orig_prog = prog; 1102 1103 /* 1104 * If BPF JIT was not enabled then we must fall back to 1105 * the interpreter. 1106 */ 1107 if (!prog->jit_requested) 1108 return orig_prog; 1109 1110 tmp = bpf_jit_blind_constants(prog); 1111 /* 1112 * If blinding was requested and we failed during blinding, 1113 * we must fall back to the interpreter. Otherwise, we save 1114 * the new JITed code. 1115 */ 1116 if (IS_ERR(tmp)) 1117 return orig_prog; 1118 1119 if (tmp != prog) { 1120 tmp_blinded = true; 1121 prog = tmp; 1122 } 1123 1124 jit_data = prog->aux->jit_data; 1125 if (!jit_data) { 1126 jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL); 1127 if (!jit_data) { 1128 prog = orig_prog; 1129 goto out; 1130 } 1131 prog->aux->jit_data = jit_data; 1132 } 1133 if (jit_data->ctx.offset) { 1134 ctx = jit_data->ctx; 1135 image_ptr = jit_data->image; 1136 header = jit_data->header; 1137 extra_pass = true; 1138 prog_size = sizeof(u32) * ctx.idx; 1139 goto skip_init_ctx; 1140 } 1141 1142 memset(&ctx, 0, sizeof(ctx)); 1143 ctx.prog = prog; 1144 1145 ctx.offset = kvcalloc(prog->len + 1, sizeof(u32), GFP_KERNEL); 1146 if (ctx.offset == NULL) { 1147 prog = orig_prog; 1148 goto out_offset; 1149 } 1150 1151 /* 1. Initial fake pass to compute ctx->idx and set ctx->flags */ 1152 build_prologue(&ctx); 1153 if (build_body(&ctx, extra_pass)) { 1154 prog = orig_prog; 1155 goto out_offset; 1156 } 1157 ctx.epilogue_offset = ctx.idx; 1158 build_epilogue(&ctx); 1159 1160 extable_size = prog->aux->num_exentries * sizeof(struct exception_table_entry); 1161 1162 /* Now we know the actual image size. 1163 * As each LoongArch instruction is of length 32bit, 1164 * we are translating number of JITed intructions into 1165 * the size required to store these JITed code. 1166 */ 1167 prog_size = sizeof(u32) * ctx.idx; 1168 image_size = prog_size + extable_size; 1169 /* Now we know the size of the structure to make */ 1170 header = bpf_jit_binary_alloc(image_size, &image_ptr, 1171 sizeof(u32), jit_fill_hole); 1172 if (header == NULL) { 1173 prog = orig_prog; 1174 goto out_offset; 1175 } 1176 1177 /* 2. Now, the actual pass to generate final JIT code */ 1178 ctx.image = (union loongarch_instruction *)image_ptr; 1179 if (extable_size) 1180 prog->aux->extable = (void *)image_ptr + prog_size; 1181 1182 skip_init_ctx: 1183 ctx.idx = 0; 1184 ctx.num_exentries = 0; 1185 1186 build_prologue(&ctx); 1187 if (build_body(&ctx, extra_pass)) { 1188 bpf_jit_binary_free(header); 1189 prog = orig_prog; 1190 goto out_offset; 1191 } 1192 build_epilogue(&ctx); 1193 1194 /* 3. Extra pass to validate JITed code */ 1195 if (validate_code(&ctx)) { 1196 bpf_jit_binary_free(header); 1197 prog = orig_prog; 1198 goto out_offset; 1199 } 1200 1201 /* And we're done */ 1202 if (bpf_jit_enable > 1) 1203 bpf_jit_dump(prog->len, prog_size, 2, ctx.image); 1204 1205 /* Update the icache */ 1206 flush_icache_range((unsigned long)header, (unsigned long)(ctx.image + ctx.idx)); 1207 1208 if (!prog->is_func || extra_pass) { 1209 if (extra_pass && ctx.idx != jit_data->ctx.idx) { 1210 pr_err_once("multi-func JIT bug %d != %d\n", 1211 ctx.idx, jit_data->ctx.idx); 1212 bpf_jit_binary_free(header); 1213 prog->bpf_func = NULL; 1214 prog->jited = 0; 1215 prog->jited_len = 0; 1216 goto out_offset; 1217 } 1218 bpf_jit_binary_lock_ro(header); 1219 } else { 1220 jit_data->ctx = ctx; 1221 jit_data->image = image_ptr; 1222 jit_data->header = header; 1223 } 1224 prog->jited = 1; 1225 prog->jited_len = prog_size; 1226 prog->bpf_func = (void *)ctx.image; 1227 1228 if (!prog->is_func || extra_pass) { 1229 int i; 1230 1231 /* offset[prog->len] is the size of program */ 1232 for (i = 0; i <= prog->len; i++) 1233 ctx.offset[i] *= LOONGARCH_INSN_SIZE; 1234 bpf_prog_fill_jited_linfo(prog, ctx.offset + 1); 1235 1236 out_offset: 1237 kvfree(ctx.offset); 1238 kfree(jit_data); 1239 prog->aux->jit_data = NULL; 1240 } 1241 1242 out: 1243 if (tmp_blinded) 1244 bpf_jit_prog_release_other(prog, prog == orig_prog ? tmp : orig_prog); 1245 1246 out_offset = -1; 1247 1248 return prog; 1249 } 1250 1251 /* Indicate the JIT backend supports mixing bpf2bpf and tailcalls. */ 1252 bool bpf_jit_supports_subprog_tailcalls(void) 1253 { 1254 return true; 1255 } 1256