1 // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) 2 /* Copyright (c) 2021 Facebook */ 3 #include <stdio.h> 4 #include <stdlib.h> 5 #include <string.h> 6 #include <errno.h> 7 #include <asm/byteorder.h> 8 #include <linux/filter.h> 9 #include <sys/param.h> 10 #include "btf.h" 11 #include "bpf.h" 12 #include "libbpf.h" 13 #include "libbpf_internal.h" 14 #include "hashmap.h" 15 #include "bpf_gen_internal.h" 16 #include "skel_internal.h" 17 18 #define MAX_USED_MAPS 64 19 #define MAX_USED_PROGS 32 20 #define MAX_KFUNC_DESCS 256 21 #define MAX_FD_ARRAY_SZ (MAX_USED_MAPS + MAX_KFUNC_DESCS) 22 23 /* The following structure describes the stack layout of the loader program. 24 * In addition R6 contains the pointer to context. 25 * R7 contains the result of the last sys_bpf command (typically error or FD). 26 * R9 contains the result of the last sys_close command. 27 * 28 * Naming convention: 29 * ctx - bpf program context 30 * stack - bpf program stack 31 * blob - bpf_attr-s, strings, insns, map data. 32 * All the bytes that loader prog will use for read/write. 33 */ 34 struct loader_stack { 35 __u32 btf_fd; 36 __u32 inner_map_fd; 37 __u32 prog_fd[MAX_USED_PROGS]; 38 }; 39 40 #define stack_off(field) \ 41 (__s16)(-sizeof(struct loader_stack) + offsetof(struct loader_stack, field)) 42 43 #define attr_field(attr, field) (attr + offsetof(union bpf_attr, field)) 44 45 static int blob_fd_array_off(struct bpf_gen *gen, int index) 46 { 47 return gen->fd_array + index * sizeof(int); 48 } 49 50 static int realloc_insn_buf(struct bpf_gen *gen, __u32 size) 51 { 52 size_t off = gen->insn_cur - gen->insn_start; 53 void *insn_start; 54 55 if (gen->error) 56 return gen->error; 57 if (size > INT32_MAX || off + size > INT32_MAX) { 58 gen->error = -ERANGE; 59 return -ERANGE; 60 } 61 insn_start = realloc(gen->insn_start, off + size); 62 if (!insn_start) { 63 gen->error = -ENOMEM; 64 free(gen->insn_start); 65 gen->insn_start = NULL; 66 gen->insn_cur = NULL; 67 return -ENOMEM; 68 } 69 gen->insn_start = insn_start; 70 gen->insn_cur = insn_start + off; 71 return 0; 72 } 73 74 static int realloc_data_buf(struct bpf_gen *gen, __u32 size) 75 { 76 size_t off = gen->data_cur - gen->data_start; 77 void *data_start; 78 79 if (gen->error) 80 return gen->error; 81 if (size > INT32_MAX || off + size > INT32_MAX) { 82 gen->error = -ERANGE; 83 return -ERANGE; 84 } 85 data_start = realloc(gen->data_start, off + size); 86 if (!data_start) { 87 gen->error = -ENOMEM; 88 free(gen->data_start); 89 gen->data_start = NULL; 90 gen->data_cur = NULL; 91 return -ENOMEM; 92 } 93 gen->data_start = data_start; 94 gen->data_cur = data_start + off; 95 return 0; 96 } 97 98 static void emit(struct bpf_gen *gen, struct bpf_insn insn) 99 { 100 if (realloc_insn_buf(gen, sizeof(insn))) 101 return; 102 memcpy(gen->insn_cur, &insn, sizeof(insn)); 103 gen->insn_cur += sizeof(insn); 104 } 105 106 static void emit2(struct bpf_gen *gen, struct bpf_insn insn1, struct bpf_insn insn2) 107 { 108 emit(gen, insn1); 109 emit(gen, insn2); 110 } 111 112 static int add_data(struct bpf_gen *gen, const void *data, __u32 size); 113 static void emit_sys_close_blob(struct bpf_gen *gen, int blob_off); 114 static void emit_signature_match(struct bpf_gen *gen); 115 116 void bpf_gen__init(struct bpf_gen *gen, int log_level, int nr_progs, int nr_maps) 117 { 118 size_t stack_sz = sizeof(struct loader_stack), nr_progs_sz; 119 int i; 120 121 gen->fd_array = add_data(gen, NULL, MAX_FD_ARRAY_SZ * sizeof(int)); 122 gen->log_level = log_level; 123 /* save ctx pointer into R6 */ 124 emit(gen, BPF_MOV64_REG(BPF_REG_6, BPF_REG_1)); 125 126 /* bzero stack */ 127 emit(gen, BPF_MOV64_REG(BPF_REG_1, BPF_REG_10)); 128 emit(gen, BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -stack_sz)); 129 emit(gen, BPF_MOV64_IMM(BPF_REG_2, stack_sz)); 130 emit(gen, BPF_MOV64_IMM(BPF_REG_3, 0)); 131 emit(gen, BPF_EMIT_CALL(BPF_FUNC_probe_read_kernel)); 132 133 /* amount of stack actually used, only used to calculate iterations, not stack offset */ 134 nr_progs_sz = offsetof(struct loader_stack, prog_fd[nr_progs]); 135 /* jump over cleanup code */ 136 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 137 /* size of cleanup code below (including map fd cleanup) */ 138 (nr_progs_sz / 4) * 3 + 2 + 139 /* 6 insns for emit_sys_close_blob, 140 * 6 insns for debug_regs in emit_sys_close_blob 141 */ 142 nr_maps * (6 + (gen->log_level ? 6 : 0)))); 143 144 /* remember the label where all error branches will jump to */ 145 gen->cleanup_label = gen->insn_cur - gen->insn_start; 146 /* emit cleanup code: close all temp FDs */ 147 for (i = 0; i < nr_progs_sz; i += 4) { 148 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_10, -stack_sz + i)); 149 emit(gen, BPF_JMP_IMM(BPF_JSLE, BPF_REG_1, 0, 1)); 150 emit(gen, BPF_EMIT_CALL(BPF_FUNC_sys_close)); 151 } 152 for (i = 0; i < nr_maps; i++) 153 emit_sys_close_blob(gen, blob_fd_array_off(gen, i)); 154 /* R7 contains the error code from sys_bpf. Copy it into R0 and exit. */ 155 emit(gen, BPF_MOV64_REG(BPF_REG_0, BPF_REG_7)); 156 emit(gen, BPF_EXIT_INSN()); 157 if (OPTS_GET(gen->opts, gen_hash, false)) 158 emit_signature_match(gen); 159 } 160 161 static int add_data(struct bpf_gen *gen, const void *data, __u32 size) 162 { 163 __u32 size8 = roundup(size, 8); 164 __u64 zero = 0; 165 void *prev; 166 167 if (realloc_data_buf(gen, size8)) 168 return 0; 169 prev = gen->data_cur; 170 if (data) { 171 memcpy(gen->data_cur, data, size); 172 memcpy(gen->data_cur + size, &zero, size8 - size); 173 } else { 174 memset(gen->data_cur, 0, size8); 175 } 176 gen->data_cur += size8; 177 return prev - gen->data_start; 178 } 179 180 /* Get index for map_fd/btf_fd slot in reserved fd_array, or in data relative 181 * to start of fd_array. Caller can decide if it is usable or not. 182 */ 183 static int add_map_fd(struct bpf_gen *gen) 184 { 185 if (gen->nr_maps == MAX_USED_MAPS) { 186 pr_warn("Total maps exceeds %d\n", MAX_USED_MAPS); 187 gen->error = -E2BIG; 188 return 0; 189 } 190 return gen->nr_maps++; 191 } 192 193 static int add_kfunc_btf_fd(struct bpf_gen *gen) 194 { 195 int cur; 196 197 if (gen->nr_fd_array == MAX_KFUNC_DESCS) { 198 cur = add_data(gen, NULL, sizeof(int)); 199 return (cur - gen->fd_array) / sizeof(int); 200 } 201 return MAX_USED_MAPS + gen->nr_fd_array++; 202 } 203 204 static int insn_bytes_to_bpf_size(__u32 sz) 205 { 206 switch (sz) { 207 case 8: return BPF_DW; 208 case 4: return BPF_W; 209 case 2: return BPF_H; 210 case 1: return BPF_B; 211 default: return -1; 212 } 213 } 214 215 /* *(u64 *)(blob + off) = (u64)(void *)(blob + data) */ 216 static void emit_rel_store(struct bpf_gen *gen, int off, int data) 217 { 218 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE, 219 0, 0, 0, data)); 220 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE, 221 0, 0, 0, off)); 222 emit(gen, BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, 0)); 223 } 224 225 static void move_blob2blob(struct bpf_gen *gen, int off, int size, int blob_off) 226 { 227 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_2, BPF_PSEUDO_MAP_IDX_VALUE, 228 0, 0, 0, blob_off)); 229 emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_2, 0)); 230 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE, 231 0, 0, 0, off)); 232 emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_1, BPF_REG_0, 0)); 233 } 234 235 static void move_blob2ctx(struct bpf_gen *gen, int ctx_off, int size, int blob_off) 236 { 237 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE, 238 0, 0, 0, blob_off)); 239 emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_1, 0)); 240 emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_6, BPF_REG_0, ctx_off)); 241 } 242 243 static void move_ctx2blob(struct bpf_gen *gen, int off, int size, int ctx_off, 244 bool check_non_zero) 245 { 246 emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_6, ctx_off)); 247 if (check_non_zero) 248 /* If value in ctx is zero don't update the blob. 249 * For example: when ctx->map.max_entries == 0, keep default max_entries from bpf.c 250 */ 251 emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3)); 252 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE, 253 0, 0, 0, off)); 254 emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_1, BPF_REG_0, 0)); 255 } 256 257 static void move_stack2blob(struct bpf_gen *gen, int off, int size, int stack_off) 258 { 259 emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_10, stack_off)); 260 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE, 261 0, 0, 0, off)); 262 emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_1, BPF_REG_0, 0)); 263 } 264 265 static void move_stack2ctx(struct bpf_gen *gen, int ctx_off, int size, int stack_off) 266 { 267 emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_10, stack_off)); 268 emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_6, BPF_REG_0, ctx_off)); 269 } 270 271 static void emit_sys_bpf(struct bpf_gen *gen, int cmd, int attr, int attr_size) 272 { 273 emit(gen, BPF_MOV64_IMM(BPF_REG_1, cmd)); 274 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_2, BPF_PSEUDO_MAP_IDX_VALUE, 275 0, 0, 0, attr)); 276 emit(gen, BPF_MOV64_IMM(BPF_REG_3, attr_size)); 277 emit(gen, BPF_EMIT_CALL(BPF_FUNC_sys_bpf)); 278 /* remember the result in R7 */ 279 emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0)); 280 } 281 282 static bool is_simm16(__s64 value) 283 { 284 return value == (__s64)(__s16)value; 285 } 286 287 static void emit_check_err(struct bpf_gen *gen) 288 { 289 __s64 off = -(gen->insn_cur - gen->insn_start - gen->cleanup_label) / 8 - 1; 290 291 /* R7 contains result of last sys_bpf command. 292 * if (R7 < 0) goto cleanup; 293 */ 294 if (is_simm16(off)) { 295 emit(gen, BPF_JMP_IMM(BPF_JSLT, BPF_REG_7, 0, off)); 296 } else { 297 gen->error = -ERANGE; 298 } 299 } 300 301 /* reg1 and reg2 should not be R1 - R5. They can be R0, R6 - R10 */ 302 static void emit_debug(struct bpf_gen *gen, int reg1, int reg2, 303 const char *fmt, va_list args) 304 { 305 char buf[1024]; 306 int addr, len, ret; 307 308 if (!gen->log_level) 309 return; 310 ret = vsnprintf(buf, sizeof(buf), fmt, args); 311 if (ret < 1024 - 7 && reg1 >= 0 && reg2 < 0) 312 /* The special case to accommodate common debug_ret(): 313 * to avoid specifying BPF_REG_7 and adding " r=%%d" to 314 * prints explicitly. 315 */ 316 strcat(buf, " r=%d"); 317 len = strlen(buf) + 1; 318 addr = add_data(gen, buf, len); 319 320 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE, 321 0, 0, 0, addr)); 322 emit(gen, BPF_MOV64_IMM(BPF_REG_2, len)); 323 if (reg1 >= 0) 324 emit(gen, BPF_MOV64_REG(BPF_REG_3, reg1)); 325 if (reg2 >= 0) 326 emit(gen, BPF_MOV64_REG(BPF_REG_4, reg2)); 327 emit(gen, BPF_EMIT_CALL(BPF_FUNC_trace_printk)); 328 } 329 330 static void debug_regs(struct bpf_gen *gen, int reg1, int reg2, const char *fmt, ...) 331 { 332 va_list args; 333 334 va_start(args, fmt); 335 emit_debug(gen, reg1, reg2, fmt, args); 336 va_end(args); 337 } 338 339 static void debug_ret(struct bpf_gen *gen, const char *fmt, ...) 340 { 341 va_list args; 342 343 va_start(args, fmt); 344 emit_debug(gen, BPF_REG_7, -1, fmt, args); 345 va_end(args); 346 } 347 348 static void __emit_sys_close(struct bpf_gen *gen) 349 { 350 emit(gen, BPF_JMP_IMM(BPF_JSLE, BPF_REG_1, 0, 351 /* 2 is the number of the following insns 352 * * 6 is additional insns in debug_regs 353 */ 354 2 + (gen->log_level ? 6 : 0))); 355 emit(gen, BPF_MOV64_REG(BPF_REG_9, BPF_REG_1)); 356 emit(gen, BPF_EMIT_CALL(BPF_FUNC_sys_close)); 357 debug_regs(gen, BPF_REG_9, BPF_REG_0, "close(%%d) = %%d"); 358 } 359 360 static void emit_sys_close_stack(struct bpf_gen *gen, int stack_off) 361 { 362 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_10, stack_off)); 363 __emit_sys_close(gen); 364 } 365 366 static void emit_sys_close_blob(struct bpf_gen *gen, int blob_off) 367 { 368 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE, 369 0, 0, 0, blob_off)); 370 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, 0)); 371 __emit_sys_close(gen); 372 } 373 374 static void compute_sha_update_offsets(struct bpf_gen *gen); 375 376 int bpf_gen__finish(struct bpf_gen *gen, int nr_progs, int nr_maps) 377 { 378 int i; 379 380 if (nr_progs < gen->nr_progs || nr_maps != gen->nr_maps) { 381 pr_warn("nr_progs %d/%d nr_maps %d/%d mismatch\n", 382 nr_progs, gen->nr_progs, nr_maps, gen->nr_maps); 383 gen->error = -EFAULT; 384 return gen->error; 385 } 386 emit_sys_close_stack(gen, stack_off(btf_fd)); 387 for (i = 0; i < gen->nr_progs; i++) 388 move_stack2ctx(gen, 389 sizeof(struct bpf_loader_ctx) + 390 sizeof(struct bpf_map_desc) * gen->nr_maps + 391 sizeof(struct bpf_prog_desc) * i + 392 offsetof(struct bpf_prog_desc, prog_fd), 4, 393 stack_off(prog_fd[i])); 394 for (i = 0; i < gen->nr_maps; i++) 395 move_blob2ctx(gen, 396 sizeof(struct bpf_loader_ctx) + 397 sizeof(struct bpf_map_desc) * i + 398 offsetof(struct bpf_map_desc, map_fd), 4, 399 blob_fd_array_off(gen, i)); 400 emit(gen, BPF_MOV64_IMM(BPF_REG_0, 0)); 401 emit(gen, BPF_EXIT_INSN()); 402 if (!gen->error) { 403 struct gen_loader_opts *opts = gen->opts; 404 405 if (OPTS_GET(opts, gen_hash, false)) 406 compute_sha_update_offsets(gen); 407 408 opts->insns = gen->insn_start; 409 opts->insns_sz = gen->insn_cur - gen->insn_start; 410 opts->data = gen->data_start; 411 opts->data_sz = gen->data_cur - gen->data_start; 412 413 /* use target endianness for embedded loader */ 414 if (gen->swapped_endian) { 415 struct bpf_insn *insn = (struct bpf_insn *)opts->insns; 416 int insn_cnt = opts->insns_sz / sizeof(struct bpf_insn); 417 418 for (i = 0; i < insn_cnt; i++) 419 bpf_insn_bswap(insn++); 420 } 421 } 422 pr_debug("gen: finish %s\n", errstr(gen->error)); 423 return gen->error; 424 } 425 426 void bpf_gen__free(struct bpf_gen *gen) 427 { 428 if (!gen) 429 return; 430 free(gen->data_start); 431 free(gen->insn_start); 432 free(gen); 433 } 434 435 /* 436 * Fields of bpf_attr are set to values in native byte-order before being 437 * written to the target-bound data blob, and may need endian conversion. 438 * This macro allows providing the correct value in situ more simply than 439 * writing a separate converter for *all fields* of *all records* included 440 * in union bpf_attr. Note that sizeof(rval) should match the assignment 441 * target to avoid runtime problems. 442 */ 443 #define tgt_endian(rval) ({ \ 444 typeof(rval) _val = (rval); \ 445 if (gen->swapped_endian) { \ 446 switch (sizeof(_val)) { \ 447 case 1: break; \ 448 case 2: _val = bswap_16(_val); break; \ 449 case 4: _val = bswap_32(_val); break; \ 450 case 8: _val = bswap_64(_val); break; \ 451 default: pr_warn("unsupported bswap size!\n"); \ 452 } \ 453 } \ 454 _val; \ 455 }) 456 457 static void compute_sha_update_offsets(struct bpf_gen *gen) 458 { 459 __u64 sha[SHA256_DWORD_SIZE]; 460 __u64 sha_dw; 461 int i; 462 463 libbpf_sha256(gen->data_start, gen->data_cur - gen->data_start, (__u8 *)sha); 464 for (i = 0; i < SHA256_DWORD_SIZE; i++) { 465 struct bpf_insn *insn = 466 (struct bpf_insn *)(gen->insn_start + gen->hash_insn_offset[i]); 467 sha_dw = tgt_endian(sha[i]); 468 insn[0].imm = (__u32)sha_dw; 469 insn[1].imm = sha_dw >> 32; 470 } 471 } 472 473 void bpf_gen__load_btf(struct bpf_gen *gen, const void *btf_raw_data, 474 __u32 btf_raw_size) 475 { 476 int attr_size = offsetofend(union bpf_attr, btf_log_level); 477 int btf_data, btf_load_attr; 478 union bpf_attr attr; 479 480 memset(&attr, 0, attr_size); 481 btf_data = add_data(gen, btf_raw_data, btf_raw_size); 482 483 attr.btf_size = tgt_endian(btf_raw_size); 484 btf_load_attr = add_data(gen, &attr, attr_size); 485 pr_debug("gen: load_btf: off %d size %d, attr: off %d size %d\n", 486 btf_data, btf_raw_size, btf_load_attr, attr_size); 487 488 /* populate union bpf_attr with user provided log details */ 489 move_ctx2blob(gen, attr_field(btf_load_attr, btf_log_level), 4, 490 offsetof(struct bpf_loader_ctx, log_level), false); 491 move_ctx2blob(gen, attr_field(btf_load_attr, btf_log_size), 4, 492 offsetof(struct bpf_loader_ctx, log_size), false); 493 move_ctx2blob(gen, attr_field(btf_load_attr, btf_log_buf), 8, 494 offsetof(struct bpf_loader_ctx, log_buf), false); 495 /* populate union bpf_attr with a pointer to the BTF data */ 496 emit_rel_store(gen, attr_field(btf_load_attr, btf), btf_data); 497 /* emit BTF_LOAD command */ 498 emit_sys_bpf(gen, BPF_BTF_LOAD, btf_load_attr, attr_size); 499 debug_ret(gen, "btf_load size %d", btf_raw_size); 500 emit_check_err(gen); 501 /* remember btf_fd in the stack, if successful */ 502 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_7, stack_off(btf_fd))); 503 } 504 505 void bpf_gen__map_create(struct bpf_gen *gen, 506 enum bpf_map_type map_type, 507 const char *map_name, 508 __u32 key_size, __u32 value_size, __u32 max_entries, 509 struct bpf_map_create_opts *map_attr, int map_idx) 510 { 511 int attr_size = offsetofend(union bpf_attr, map_extra); 512 bool close_inner_map_fd = false; 513 int map_create_attr, idx; 514 union bpf_attr attr; 515 516 memset(&attr, 0, attr_size); 517 attr.map_type = tgt_endian(map_type); 518 attr.key_size = tgt_endian(key_size); 519 attr.value_size = tgt_endian(value_size); 520 attr.map_flags = tgt_endian(map_attr->map_flags); 521 attr.map_extra = tgt_endian(map_attr->map_extra); 522 if (map_name) 523 libbpf_strlcpy(attr.map_name, map_name, sizeof(attr.map_name)); 524 attr.numa_node = tgt_endian(map_attr->numa_node); 525 attr.map_ifindex = tgt_endian(map_attr->map_ifindex); 526 attr.max_entries = tgt_endian(max_entries); 527 attr.btf_key_type_id = tgt_endian(map_attr->btf_key_type_id); 528 attr.btf_value_type_id = tgt_endian(map_attr->btf_value_type_id); 529 530 map_create_attr = add_data(gen, &attr, attr_size); 531 pr_debug("gen: map_create: %s idx %d type %d value_type_id %d, attr: off %d size %d\n", 532 map_name, map_idx, map_type, map_attr->btf_value_type_id, 533 map_create_attr, attr_size); 534 535 if (map_attr->btf_value_type_id) 536 /* populate union bpf_attr with btf_fd saved in the stack earlier */ 537 move_stack2blob(gen, attr_field(map_create_attr, btf_fd), 4, 538 stack_off(btf_fd)); 539 switch (map_type) { 540 case BPF_MAP_TYPE_ARRAY_OF_MAPS: 541 case BPF_MAP_TYPE_HASH_OF_MAPS: 542 move_stack2blob(gen, attr_field(map_create_attr, inner_map_fd), 4, 543 stack_off(inner_map_fd)); 544 close_inner_map_fd = true; 545 break; 546 default: 547 break; 548 } 549 /* conditionally update max_entries */ 550 if (map_idx >= 0) 551 move_ctx2blob(gen, attr_field(map_create_attr, max_entries), 4, 552 sizeof(struct bpf_loader_ctx) + 553 sizeof(struct bpf_map_desc) * map_idx + 554 offsetof(struct bpf_map_desc, max_entries), 555 true /* check that max_entries != 0 */); 556 /* emit MAP_CREATE command */ 557 emit_sys_bpf(gen, BPF_MAP_CREATE, map_create_attr, attr_size); 558 debug_ret(gen, "map_create %s idx %d type %d value_size %d value_btf_id %d", 559 map_name, map_idx, map_type, value_size, 560 map_attr->btf_value_type_id); 561 emit_check_err(gen); 562 /* remember map_fd in the stack, if successful */ 563 if (map_idx < 0) { 564 /* This bpf_gen__map_create() function is called with map_idx >= 0 565 * for all maps that libbpf loading logic tracks. 566 * It's called with -1 to create an inner map. 567 */ 568 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_7, 569 stack_off(inner_map_fd))); 570 } else if (map_idx != gen->nr_maps) { 571 gen->error = -EDOM; /* internal bug */ 572 return; 573 } else { 574 /* add_map_fd does gen->nr_maps++ */ 575 idx = add_map_fd(gen); 576 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE, 577 0, 0, 0, blob_fd_array_off(gen, idx))); 578 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_7, 0)); 579 } 580 if (close_inner_map_fd) 581 emit_sys_close_stack(gen, stack_off(inner_map_fd)); 582 } 583 584 static void emit_signature_match(struct bpf_gen *gen) 585 { 586 __s64 off; 587 int i; 588 589 for (i = 0; i < SHA256_DWORD_SIZE; i++) { 590 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX, 591 0, 0, 0, 0)); 592 emit(gen, BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, i * sizeof(__u64))); 593 gen->hash_insn_offset[i] = gen->insn_cur - gen->insn_start; 594 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_3, 0, 0, 0, 0, 0)); 595 596 off = -(gen->insn_cur - gen->insn_start - gen->cleanup_label) / 8 - 2; 597 if (is_simm16(off)) { 598 emit(gen, BPF_MOV64_IMM(BPF_REG_7, -EINVAL)); 599 emit(gen, BPF_JMP_REG(BPF_JNE, BPF_REG_2, BPF_REG_3, off)); 600 } else { 601 gen->error = -ERANGE; 602 } 603 } 604 } 605 606 void bpf_gen__record_attach_target(struct bpf_gen *gen, const char *attach_name, 607 enum bpf_attach_type type) 608 { 609 const char *prefix; 610 int kind, ret; 611 612 btf_get_kernel_prefix_kind(type, &prefix, &kind); 613 gen->attach_kind = kind; 614 ret = snprintf(gen->attach_target, sizeof(gen->attach_target), "%s%s", 615 prefix, attach_name); 616 if (ret >= sizeof(gen->attach_target)) 617 gen->error = -ENOSPC; 618 } 619 620 static void emit_find_attach_target(struct bpf_gen *gen) 621 { 622 int name, len = strlen(gen->attach_target) + 1; 623 624 pr_debug("gen: find_attach_tgt %s %d\n", gen->attach_target, gen->attach_kind); 625 name = add_data(gen, gen->attach_target, len); 626 627 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE, 628 0, 0, 0, name)); 629 emit(gen, BPF_MOV64_IMM(BPF_REG_2, len)); 630 emit(gen, BPF_MOV64_IMM(BPF_REG_3, gen->attach_kind)); 631 emit(gen, BPF_MOV64_IMM(BPF_REG_4, 0)); 632 emit(gen, BPF_EMIT_CALL(BPF_FUNC_btf_find_by_name_kind)); 633 emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0)); 634 debug_ret(gen, "find_by_name_kind(%s,%d)", 635 gen->attach_target, gen->attach_kind); 636 emit_check_err(gen); 637 /* if successful, btf_id is in lower 32-bit of R7 and 638 * btf_obj_fd is in upper 32-bit 639 */ 640 } 641 642 void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak, 643 bool is_typeless, bool is_ld64, int kind, int insn_idx) 644 { 645 struct ksym_relo_desc *relo; 646 647 relo = libbpf_reallocarray(gen->relos, gen->relo_cnt + 1, sizeof(*relo)); 648 if (!relo) { 649 gen->error = -ENOMEM; 650 return; 651 } 652 gen->relos = relo; 653 relo += gen->relo_cnt; 654 relo->name = name; 655 relo->is_weak = is_weak; 656 relo->is_typeless = is_typeless; 657 relo->is_ld64 = is_ld64; 658 relo->kind = kind; 659 relo->insn_idx = insn_idx; 660 gen->relo_cnt++; 661 } 662 663 /* returns existing ksym_desc with ref incremented, or inserts a new one */ 664 static struct ksym_desc *get_ksym_desc(struct bpf_gen *gen, struct ksym_relo_desc *relo) 665 { 666 struct ksym_desc *kdesc; 667 int i; 668 669 for (i = 0; i < gen->nr_ksyms; i++) { 670 kdesc = &gen->ksyms[i]; 671 if (kdesc->kind == relo->kind && kdesc->is_ld64 == relo->is_ld64 && 672 !strcmp(kdesc->name, relo->name)) { 673 kdesc->ref++; 674 return kdesc; 675 } 676 } 677 kdesc = libbpf_reallocarray(gen->ksyms, gen->nr_ksyms + 1, sizeof(*kdesc)); 678 if (!kdesc) { 679 gen->error = -ENOMEM; 680 return NULL; 681 } 682 gen->ksyms = kdesc; 683 kdesc = &gen->ksyms[gen->nr_ksyms++]; 684 kdesc->name = relo->name; 685 kdesc->kind = relo->kind; 686 kdesc->ref = 1; 687 kdesc->off = 0; 688 kdesc->insn = 0; 689 kdesc->is_ld64 = relo->is_ld64; 690 return kdesc; 691 } 692 693 /* Overwrites BPF_REG_{0, 1, 2, 3, 4, 7} 694 * Returns result in BPF_REG_7 695 */ 696 static void emit_bpf_find_by_name_kind(struct bpf_gen *gen, struct ksym_relo_desc *relo) 697 { 698 int name_off, len = strlen(relo->name) + 1; 699 700 name_off = add_data(gen, relo->name, len); 701 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE, 702 0, 0, 0, name_off)); 703 emit(gen, BPF_MOV64_IMM(BPF_REG_2, len)); 704 emit(gen, BPF_MOV64_IMM(BPF_REG_3, relo->kind)); 705 emit(gen, BPF_MOV64_IMM(BPF_REG_4, 0)); 706 emit(gen, BPF_EMIT_CALL(BPF_FUNC_btf_find_by_name_kind)); 707 emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0)); 708 debug_ret(gen, "find_by_name_kind(%s,%d)", relo->name, relo->kind); 709 } 710 711 /* Overwrites BPF_REG_{0, 1, 2, 3, 4, 7} 712 * Returns result in BPF_REG_7 713 * Returns u64 symbol addr in BPF_REG_9 714 */ 715 static void emit_bpf_kallsyms_lookup_name(struct bpf_gen *gen, struct ksym_relo_desc *relo) 716 { 717 int name_off, len = strlen(relo->name) + 1, res_off; 718 719 name_off = add_data(gen, relo->name, len); 720 res_off = add_data(gen, NULL, 8); /* res is u64 */ 721 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE, 722 0, 0, 0, name_off)); 723 emit(gen, BPF_MOV64_IMM(BPF_REG_2, len)); 724 emit(gen, BPF_MOV64_IMM(BPF_REG_3, 0)); 725 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_4, BPF_PSEUDO_MAP_IDX_VALUE, 726 0, 0, 0, res_off)); 727 emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_4)); 728 emit(gen, BPF_EMIT_CALL(BPF_FUNC_kallsyms_lookup_name)); 729 emit(gen, BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0)); 730 emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0)); 731 debug_ret(gen, "kallsyms_lookup_name(%s,%d)", relo->name, relo->kind); 732 } 733 734 /* Expects: 735 * BPF_REG_8 - pointer to instruction 736 * 737 * We need to reuse BTF fd for same symbol otherwise each relocation takes a new 738 * index, while kernel limits total kfunc BTFs to 256. For duplicate symbols, 739 * this would mean a new BTF fd index for each entry. By pairing symbol name 740 * with index, we get the insn->imm, insn->off pairing that kernel uses for 741 * kfunc_tab, which becomes the effective limit even though all of them may 742 * share same index in fd_array (such that kfunc_btf_tab has 1 element). 743 */ 744 static void emit_relo_kfunc_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn) 745 { 746 struct ksym_desc *kdesc; 747 int btf_fd_idx; 748 749 kdesc = get_ksym_desc(gen, relo); 750 if (!kdesc) 751 return; 752 /* try to copy from existing bpf_insn */ 753 if (kdesc->ref > 1) { 754 move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4, 755 kdesc->insn + offsetof(struct bpf_insn, imm)); 756 move_blob2blob(gen, insn + offsetof(struct bpf_insn, off), 2, 757 kdesc->insn + offsetof(struct bpf_insn, off)); 758 goto log; 759 } 760 /* remember insn offset, so we can copy BTF ID and FD later */ 761 kdesc->insn = insn; 762 emit_bpf_find_by_name_kind(gen, relo); 763 if (!relo->is_weak) 764 emit_check_err(gen); 765 /* get index in fd_array to store BTF FD at */ 766 btf_fd_idx = add_kfunc_btf_fd(gen); 767 if (btf_fd_idx > INT16_MAX) { 768 pr_warn("BTF fd off %d for kfunc %s exceeds INT16_MAX, cannot process relocation\n", 769 btf_fd_idx, relo->name); 770 gen->error = -E2BIG; 771 return; 772 } 773 kdesc->off = btf_fd_idx; 774 /* jump to success case */ 775 emit(gen, BPF_JMP_IMM(BPF_JSGE, BPF_REG_7, 0, 3)); 776 /* set value for imm, off as 0 */ 777 emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, offsetof(struct bpf_insn, imm), 0)); 778 emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), 0)); 779 /* skip success case for ret < 0 */ 780 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 10)); 781 /* store btf_id into insn[insn_idx].imm */ 782 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7, offsetof(struct bpf_insn, imm))); 783 /* obtain fd in BPF_REG_9 */ 784 emit(gen, BPF_MOV64_REG(BPF_REG_9, BPF_REG_7)); 785 emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_9, 32)); 786 /* load fd_array slot pointer */ 787 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE, 788 0, 0, 0, blob_fd_array_off(gen, btf_fd_idx))); 789 /* store BTF fd in slot, 0 for vmlinux */ 790 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_9, 0)); 791 /* jump to insn[insn_idx].off store if fd denotes module BTF */ 792 emit(gen, BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 0, 2)); 793 /* set the default value for off */ 794 emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), 0)); 795 /* skip BTF fd store for vmlinux BTF */ 796 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 1)); 797 /* store index into insn[insn_idx].off */ 798 emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), btf_fd_idx)); 799 log: 800 if (!gen->log_level) 801 return; 802 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_8, 803 offsetof(struct bpf_insn, imm))); 804 emit(gen, BPF_LDX_MEM(BPF_H, BPF_REG_9, BPF_REG_8, 805 offsetof(struct bpf_insn, off))); 806 debug_regs(gen, BPF_REG_7, BPF_REG_9, " func (%s:count=%d): imm: %%d, off: %%d", 807 relo->name, kdesc->ref); 808 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE, 809 0, 0, 0, blob_fd_array_off(gen, kdesc->off))); 810 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_9, BPF_REG_0, 0)); 811 debug_regs(gen, BPF_REG_9, -1, " func (%s:count=%d): btf_fd", 812 relo->name, kdesc->ref); 813 } 814 815 static void emit_ksym_relo_log(struct bpf_gen *gen, struct ksym_relo_desc *relo, 816 int ref) 817 { 818 if (!gen->log_level) 819 return; 820 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_8, 821 offsetof(struct bpf_insn, imm))); 822 emit(gen, BPF_LDX_MEM(BPF_H, BPF_REG_9, BPF_REG_8, sizeof(struct bpf_insn) + 823 offsetof(struct bpf_insn, imm))); 824 debug_regs(gen, BPF_REG_7, BPF_REG_9, " var t=%d w=%d (%s:count=%d): imm[0]: %%d, imm[1]: %%d", 825 relo->is_typeless, relo->is_weak, relo->name, ref); 826 emit(gen, BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_8, offsetofend(struct bpf_insn, code))); 827 debug_regs(gen, BPF_REG_9, -1, " var t=%d w=%d (%s:count=%d): insn.reg", 828 relo->is_typeless, relo->is_weak, relo->name, ref); 829 } 830 831 /* Expects: 832 * BPF_REG_8 - pointer to instruction 833 */ 834 static void emit_relo_ksym_typeless(struct bpf_gen *gen, 835 struct ksym_relo_desc *relo, int insn) 836 { 837 struct ksym_desc *kdesc; 838 839 kdesc = get_ksym_desc(gen, relo); 840 if (!kdesc) 841 return; 842 /* try to copy from existing ldimm64 insn */ 843 if (kdesc->ref > 1) { 844 move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4, 845 kdesc->insn + offsetof(struct bpf_insn, imm)); 846 move_blob2blob(gen, insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 4, 847 kdesc->insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm)); 848 goto log; 849 } 850 /* remember insn offset, so we can copy ksym addr later */ 851 kdesc->insn = insn; 852 /* skip typeless ksym_desc in fd closing loop in cleanup_relos */ 853 kdesc->typeless = true; 854 emit_bpf_kallsyms_lookup_name(gen, relo); 855 emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_7, -ENOENT, 1)); 856 emit_check_err(gen); 857 /* store lower half of addr into insn[insn_idx].imm */ 858 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_9, offsetof(struct bpf_insn, imm))); 859 /* store upper half of addr into insn[insn_idx + 1].imm */ 860 emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_9, 32)); 861 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_9, 862 sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm))); 863 log: 864 emit_ksym_relo_log(gen, relo, kdesc->ref); 865 } 866 867 static __u32 src_reg_mask(struct bpf_gen *gen) 868 { 869 #if defined(__LITTLE_ENDIAN_BITFIELD) /* src_reg,dst_reg,... */ 870 return gen->swapped_endian ? 0xf0 : 0x0f; 871 #elif defined(__BIG_ENDIAN_BITFIELD) /* dst_reg,src_reg,... */ 872 return gen->swapped_endian ? 0x0f : 0xf0; 873 #else 874 #error "Unsupported bit endianness, cannot proceed" 875 #endif 876 } 877 878 /* Expects: 879 * BPF_REG_8 - pointer to instruction 880 */ 881 static void emit_relo_ksym_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn) 882 { 883 struct ksym_desc *kdesc; 884 __u32 reg_mask; 885 886 kdesc = get_ksym_desc(gen, relo); 887 if (!kdesc) 888 return; 889 /* try to copy from existing ldimm64 insn */ 890 if (kdesc->ref > 1) { 891 move_blob2blob(gen, insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 4, 892 kdesc->insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm)); 893 move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4, 894 kdesc->insn + offsetof(struct bpf_insn, imm)); 895 /* jump over src_reg adjustment if imm (btf_id) is not 0, reuse BPF_REG_0 from move_blob2blob 896 * If btf_id is zero, clear BPF_PSEUDO_BTF_ID flag in src_reg of ld_imm64 insn 897 */ 898 emit(gen, BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 3)); 899 goto clear_src_reg; 900 } 901 /* remember insn offset, so we can copy BTF ID and FD later */ 902 kdesc->insn = insn; 903 emit_bpf_find_by_name_kind(gen, relo); 904 if (!relo->is_weak) 905 emit_check_err(gen); 906 /* jump to success case */ 907 emit(gen, BPF_JMP_IMM(BPF_JSGE, BPF_REG_7, 0, 3)); 908 /* set values for insn[insn_idx].imm, insn[insn_idx + 1].imm as 0 */ 909 emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, offsetof(struct bpf_insn, imm), 0)); 910 emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 0)); 911 /* skip success case for ret < 0 */ 912 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 4)); 913 /* store btf_id into insn[insn_idx].imm */ 914 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7, offsetof(struct bpf_insn, imm))); 915 /* store btf_obj_fd into insn[insn_idx + 1].imm */ 916 emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_7, 32)); 917 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7, 918 sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm))); 919 /* skip src_reg adjustment */ 920 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 3)); 921 clear_src_reg: 922 /* clear bpf_object__relocate_data's src_reg assignment, otherwise we get a verifier failure */ 923 reg_mask = src_reg_mask(gen); 924 emit(gen, BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_8, offsetofend(struct bpf_insn, code))); 925 emit(gen, BPF_ALU32_IMM(BPF_AND, BPF_REG_9, reg_mask)); 926 emit(gen, BPF_STX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, offsetofend(struct bpf_insn, code))); 927 928 emit_ksym_relo_log(gen, relo, kdesc->ref); 929 } 930 931 void bpf_gen__record_relo_core(struct bpf_gen *gen, 932 const struct bpf_core_relo *core_relo) 933 { 934 struct bpf_core_relo *relos; 935 936 relos = libbpf_reallocarray(gen->core_relos, gen->core_relo_cnt + 1, sizeof(*relos)); 937 if (!relos) { 938 gen->error = -ENOMEM; 939 return; 940 } 941 gen->core_relos = relos; 942 relos += gen->core_relo_cnt; 943 memcpy(relos, core_relo, sizeof(*relos)); 944 gen->core_relo_cnt++; 945 } 946 947 static void emit_relo(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insns) 948 { 949 int insn; 950 951 pr_debug("gen: emit_relo (%d): %s at %d %s\n", 952 relo->kind, relo->name, relo->insn_idx, relo->is_ld64 ? "ld64" : "call"); 953 insn = insns + sizeof(struct bpf_insn) * relo->insn_idx; 954 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_8, BPF_PSEUDO_MAP_IDX_VALUE, 0, 0, 0, insn)); 955 if (relo->is_ld64) { 956 if (relo->is_typeless) 957 emit_relo_ksym_typeless(gen, relo, insn); 958 else 959 emit_relo_ksym_btf(gen, relo, insn); 960 } else { 961 emit_relo_kfunc_btf(gen, relo, insn); 962 } 963 } 964 965 static void emit_relos(struct bpf_gen *gen, int insns) 966 { 967 int i; 968 969 for (i = 0; i < gen->relo_cnt; i++) 970 emit_relo(gen, gen->relos + i, insns); 971 } 972 973 static void cleanup_core_relo(struct bpf_gen *gen) 974 { 975 if (!gen->core_relo_cnt) 976 return; 977 free(gen->core_relos); 978 gen->core_relo_cnt = 0; 979 gen->core_relos = NULL; 980 } 981 982 static void cleanup_relos(struct bpf_gen *gen, int insns) 983 { 984 struct ksym_desc *kdesc; 985 int i, insn; 986 987 for (i = 0; i < gen->nr_ksyms; i++) { 988 kdesc = &gen->ksyms[i]; 989 /* only close fds for typed ksyms and kfuncs */ 990 if (kdesc->is_ld64 && !kdesc->typeless) { 991 /* close fd recorded in insn[insn_idx + 1].imm */ 992 insn = kdesc->insn; 993 insn += sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm); 994 emit_sys_close_blob(gen, insn); 995 } else if (!kdesc->is_ld64) { 996 emit_sys_close_blob(gen, blob_fd_array_off(gen, kdesc->off)); 997 if (kdesc->off < MAX_FD_ARRAY_SZ) 998 gen->nr_fd_array--; 999 } 1000 } 1001 if (gen->nr_ksyms) { 1002 free(gen->ksyms); 1003 gen->nr_ksyms = 0; 1004 gen->ksyms = NULL; 1005 } 1006 if (gen->relo_cnt) { 1007 free(gen->relos); 1008 gen->relo_cnt = 0; 1009 gen->relos = NULL; 1010 } 1011 cleanup_core_relo(gen); 1012 } 1013 1014 /* Convert func, line, and core relo info blobs to target endianness */ 1015 static void info_blob_bswap(struct bpf_gen *gen, int func_info, int line_info, 1016 int core_relos, struct bpf_prog_load_opts *load_attr) 1017 { 1018 struct bpf_func_info *fi = gen->data_start + func_info; 1019 struct bpf_line_info *li = gen->data_start + line_info; 1020 struct bpf_core_relo *cr = gen->data_start + core_relos; 1021 int i; 1022 1023 for (i = 0; i < load_attr->func_info_cnt; i++) 1024 bpf_func_info_bswap(fi++); 1025 1026 for (i = 0; i < load_attr->line_info_cnt; i++) 1027 bpf_line_info_bswap(li++); 1028 1029 for (i = 0; i < gen->core_relo_cnt; i++) 1030 bpf_core_relo_bswap(cr++); 1031 } 1032 1033 void bpf_gen__prog_load(struct bpf_gen *gen, 1034 enum bpf_prog_type prog_type, const char *prog_name, 1035 const char *license, struct bpf_insn *insns, size_t insn_cnt, 1036 struct bpf_prog_load_opts *load_attr, int prog_idx) 1037 { 1038 int func_info_tot_sz = load_attr->func_info_cnt * 1039 load_attr->func_info_rec_size; 1040 int line_info_tot_sz = load_attr->line_info_cnt * 1041 load_attr->line_info_rec_size; 1042 int core_relo_tot_sz = gen->core_relo_cnt * 1043 sizeof(struct bpf_core_relo); 1044 int prog_load_attr, license_off, insns_off, func_info, line_info, core_relos; 1045 int attr_size = offsetofend(union bpf_attr, core_relo_rec_size); 1046 union bpf_attr attr; 1047 1048 memset(&attr, 0, attr_size); 1049 /* add license string to blob of bytes */ 1050 license_off = add_data(gen, license, strlen(license) + 1); 1051 /* add insns to blob of bytes */ 1052 insns_off = add_data(gen, insns, insn_cnt * sizeof(struct bpf_insn)); 1053 pr_debug("gen: prog_load: prog_idx %d type %d insn off %d insns_cnt %zd license off %d\n", 1054 prog_idx, prog_type, insns_off, insn_cnt, license_off); 1055 1056 /* convert blob insns to target endianness */ 1057 if (gen->swapped_endian && !gen->error) { 1058 struct bpf_insn *insn = gen->data_start + insns_off; 1059 int i; 1060 1061 for (i = 0; i < insn_cnt; i++, insn++) 1062 bpf_insn_bswap(insn); 1063 } 1064 1065 attr.prog_type = tgt_endian(prog_type); 1066 attr.expected_attach_type = tgt_endian(load_attr->expected_attach_type); 1067 attr.attach_btf_id = tgt_endian(load_attr->attach_btf_id); 1068 attr.prog_ifindex = tgt_endian(load_attr->prog_ifindex); 1069 attr.kern_version = 0; 1070 attr.insn_cnt = tgt_endian((__u32)insn_cnt); 1071 attr.prog_flags = tgt_endian(load_attr->prog_flags); 1072 1073 attr.func_info_rec_size = tgt_endian(load_attr->func_info_rec_size); 1074 attr.func_info_cnt = tgt_endian(load_attr->func_info_cnt); 1075 func_info = add_data(gen, load_attr->func_info, func_info_tot_sz); 1076 pr_debug("gen: prog_load: func_info: off %d cnt %d rec size %d\n", 1077 func_info, load_attr->func_info_cnt, 1078 load_attr->func_info_rec_size); 1079 1080 attr.line_info_rec_size = tgt_endian(load_attr->line_info_rec_size); 1081 attr.line_info_cnt = tgt_endian(load_attr->line_info_cnt); 1082 line_info = add_data(gen, load_attr->line_info, line_info_tot_sz); 1083 pr_debug("gen: prog_load: line_info: off %d cnt %d rec size %d\n", 1084 line_info, load_attr->line_info_cnt, 1085 load_attr->line_info_rec_size); 1086 1087 attr.core_relo_rec_size = tgt_endian((__u32)sizeof(struct bpf_core_relo)); 1088 attr.core_relo_cnt = tgt_endian(gen->core_relo_cnt); 1089 core_relos = add_data(gen, gen->core_relos, core_relo_tot_sz); 1090 pr_debug("gen: prog_load: core_relos: off %d cnt %d rec size %zd\n", 1091 core_relos, gen->core_relo_cnt, 1092 sizeof(struct bpf_core_relo)); 1093 1094 /* convert all info blobs to target endianness */ 1095 if (gen->swapped_endian && !gen->error) 1096 info_blob_bswap(gen, func_info, line_info, core_relos, load_attr); 1097 1098 libbpf_strlcpy(attr.prog_name, prog_name, sizeof(attr.prog_name)); 1099 prog_load_attr = add_data(gen, &attr, attr_size); 1100 pr_debug("gen: prog_load: attr: off %d size %d\n", 1101 prog_load_attr, attr_size); 1102 1103 /* populate union bpf_attr with a pointer to license */ 1104 emit_rel_store(gen, attr_field(prog_load_attr, license), license_off); 1105 1106 /* populate union bpf_attr with a pointer to instructions */ 1107 emit_rel_store(gen, attr_field(prog_load_attr, insns), insns_off); 1108 1109 /* populate union bpf_attr with a pointer to func_info */ 1110 emit_rel_store(gen, attr_field(prog_load_attr, func_info), func_info); 1111 1112 /* populate union bpf_attr with a pointer to line_info */ 1113 emit_rel_store(gen, attr_field(prog_load_attr, line_info), line_info); 1114 1115 /* populate union bpf_attr with a pointer to core_relos */ 1116 emit_rel_store(gen, attr_field(prog_load_attr, core_relos), core_relos); 1117 1118 /* populate union bpf_attr fd_array with a pointer to data where map_fds are saved */ 1119 emit_rel_store(gen, attr_field(prog_load_attr, fd_array), gen->fd_array); 1120 1121 /* populate union bpf_attr with user provided log details */ 1122 move_ctx2blob(gen, attr_field(prog_load_attr, log_level), 4, 1123 offsetof(struct bpf_loader_ctx, log_level), false); 1124 move_ctx2blob(gen, attr_field(prog_load_attr, log_size), 4, 1125 offsetof(struct bpf_loader_ctx, log_size), false); 1126 move_ctx2blob(gen, attr_field(prog_load_attr, log_buf), 8, 1127 offsetof(struct bpf_loader_ctx, log_buf), false); 1128 /* populate union bpf_attr with btf_fd saved in the stack earlier */ 1129 move_stack2blob(gen, attr_field(prog_load_attr, prog_btf_fd), 4, 1130 stack_off(btf_fd)); 1131 if (gen->attach_kind) { 1132 emit_find_attach_target(gen); 1133 /* populate union bpf_attr with btf_id and btf_obj_fd found by helper */ 1134 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE, 1135 0, 0, 0, prog_load_attr)); 1136 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, 1137 offsetof(union bpf_attr, attach_btf_id))); 1138 emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_7, 32)); 1139 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, 1140 offsetof(union bpf_attr, attach_btf_obj_fd))); 1141 } 1142 emit_relos(gen, insns_off); 1143 /* emit PROG_LOAD command */ 1144 emit_sys_bpf(gen, BPF_PROG_LOAD, prog_load_attr, attr_size); 1145 debug_ret(gen, "prog_load %s insn_cnt %d", attr.prog_name, attr.insn_cnt); 1146 /* successful or not, close btf module FDs used in extern ksyms and attach_btf_obj_fd */ 1147 cleanup_relos(gen, insns_off); 1148 if (gen->attach_kind) { 1149 emit_sys_close_blob(gen, 1150 attr_field(prog_load_attr, attach_btf_obj_fd)); 1151 gen->attach_kind = 0; 1152 } 1153 emit_check_err(gen); 1154 /* remember prog_fd in the stack, if successful */ 1155 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_7, 1156 stack_off(prog_fd[gen->nr_progs]))); 1157 gen->nr_progs++; 1158 } 1159 1160 void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *pvalue, 1161 __u32 value_size) 1162 { 1163 int attr_size = offsetofend(union bpf_attr, flags); 1164 int map_update_attr, value, key; 1165 union bpf_attr attr; 1166 int zero = 0; 1167 1168 memset(&attr, 0, attr_size); 1169 1170 value = add_data(gen, pvalue, value_size); 1171 key = add_data(gen, &zero, sizeof(zero)); 1172 1173 /* if (map_desc[map_idx].initial_value) { 1174 * if (ctx->flags & BPF_SKEL_KERNEL) 1175 * bpf_probe_read_kernel(value, value_size, initial_value); 1176 * else 1177 * bpf_copy_from_user(value, value_size, initial_value); 1178 * } 1179 */ 1180 emit(gen, BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_6, 1181 sizeof(struct bpf_loader_ctx) + 1182 sizeof(struct bpf_map_desc) * map_idx + 1183 offsetof(struct bpf_map_desc, initial_value))); 1184 emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_3, 0, 8)); 1185 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE, 1186 0, 0, 0, value)); 1187 emit(gen, BPF_MOV64_IMM(BPF_REG_2, value_size)); 1188 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6, 1189 offsetof(struct bpf_loader_ctx, flags))); 1190 emit(gen, BPF_JMP_IMM(BPF_JSET, BPF_REG_0, BPF_SKEL_KERNEL, 2)); 1191 emit(gen, BPF_EMIT_CALL(BPF_FUNC_copy_from_user)); 1192 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 1)); 1193 emit(gen, BPF_EMIT_CALL(BPF_FUNC_probe_read_kernel)); 1194 1195 map_update_attr = add_data(gen, &attr, attr_size); 1196 pr_debug("gen: map_update_elem: idx %d, value: off %d size %d, attr: off %d size %d\n", 1197 map_idx, value, value_size, map_update_attr, attr_size); 1198 move_blob2blob(gen, attr_field(map_update_attr, map_fd), 4, 1199 blob_fd_array_off(gen, map_idx)); 1200 emit_rel_store(gen, attr_field(map_update_attr, key), key); 1201 emit_rel_store(gen, attr_field(map_update_attr, value), value); 1202 /* emit MAP_UPDATE_ELEM command */ 1203 emit_sys_bpf(gen, BPF_MAP_UPDATE_ELEM, map_update_attr, attr_size); 1204 debug_ret(gen, "update_elem idx %d value_size %d", map_idx, value_size); 1205 emit_check_err(gen); 1206 } 1207 1208 void bpf_gen__populate_outer_map(struct bpf_gen *gen, int outer_map_idx, int slot, 1209 int inner_map_idx) 1210 { 1211 int attr_size = offsetofend(union bpf_attr, flags); 1212 int map_update_attr, key; 1213 union bpf_attr attr; 1214 int tgt_slot; 1215 1216 memset(&attr, 0, attr_size); 1217 1218 tgt_slot = tgt_endian(slot); 1219 key = add_data(gen, &tgt_slot, sizeof(tgt_slot)); 1220 1221 map_update_attr = add_data(gen, &attr, attr_size); 1222 pr_debug("gen: populate_outer_map: outer %d key %d inner %d, attr: off %d size %d\n", 1223 outer_map_idx, slot, inner_map_idx, map_update_attr, attr_size); 1224 move_blob2blob(gen, attr_field(map_update_attr, map_fd), 4, 1225 blob_fd_array_off(gen, outer_map_idx)); 1226 emit_rel_store(gen, attr_field(map_update_attr, key), key); 1227 emit_rel_store(gen, attr_field(map_update_attr, value), 1228 blob_fd_array_off(gen, inner_map_idx)); 1229 1230 /* emit MAP_UPDATE_ELEM command */ 1231 emit_sys_bpf(gen, BPF_MAP_UPDATE_ELEM, map_update_attr, attr_size); 1232 debug_ret(gen, "populate_outer_map outer %d key %d inner %d", 1233 outer_map_idx, slot, inner_map_idx); 1234 emit_check_err(gen); 1235 } 1236 1237 void bpf_gen__map_freeze(struct bpf_gen *gen, int map_idx) 1238 { 1239 int attr_size = offsetofend(union bpf_attr, map_fd); 1240 int map_freeze_attr; 1241 union bpf_attr attr; 1242 1243 memset(&attr, 0, attr_size); 1244 map_freeze_attr = add_data(gen, &attr, attr_size); 1245 pr_debug("gen: map_freeze: idx %d, attr: off %d size %d\n", 1246 map_idx, map_freeze_attr, attr_size); 1247 move_blob2blob(gen, attr_field(map_freeze_attr, map_fd), 4, 1248 blob_fd_array_off(gen, map_idx)); 1249 /* emit MAP_FREEZE command */ 1250 emit_sys_bpf(gen, BPF_MAP_FREEZE, map_freeze_attr, attr_size); 1251 debug_ret(gen, "map_freeze"); 1252 emit_check_err(gen); 1253 } 1254