1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2011-2015 PLUMgrid, http://plumgrid.com 3 * Copyright (c) 2016 Facebook 4 */ 5 #include <linux/kernel.h> 6 #include <linux/types.h> 7 #include <linux/slab.h> 8 #include <linux/bpf.h> 9 #include <linux/bpf_perf_event.h> 10 #include <linux/filter.h> 11 #include <linux/uaccess.h> 12 #include <linux/ctype.h> 13 #include <linux/kprobes.h> 14 #include <linux/syscalls.h> 15 #include <linux/error-injection.h> 16 17 #include <asm/tlb.h> 18 19 #include "trace_probe.h" 20 #include "trace.h" 21 22 #ifdef CONFIG_MODULES 23 struct bpf_trace_module { 24 struct module *module; 25 struct list_head list; 26 }; 27 28 static LIST_HEAD(bpf_trace_modules); 29 static DEFINE_MUTEX(bpf_module_mutex); 30 31 static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name) 32 { 33 struct bpf_raw_event_map *btp, *ret = NULL; 34 struct bpf_trace_module *btm; 35 unsigned int i; 36 37 mutex_lock(&bpf_module_mutex); 38 list_for_each_entry(btm, &bpf_trace_modules, list) { 39 for (i = 0; i < btm->module->num_bpf_raw_events; ++i) { 40 btp = &btm->module->bpf_raw_events[i]; 41 if (!strcmp(btp->tp->name, name)) { 42 if (try_module_get(btm->module)) 43 ret = btp; 44 goto out; 45 } 46 } 47 } 48 out: 49 mutex_unlock(&bpf_module_mutex); 50 return ret; 51 } 52 #else 53 static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name) 54 { 55 return NULL; 56 } 57 #endif /* CONFIG_MODULES */ 58 59 u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 60 u64 bpf_get_stack(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 61 62 /** 63 * trace_call_bpf - invoke BPF program 64 * @call: tracepoint event 65 * @ctx: opaque context pointer 66 * 67 * kprobe handlers execute BPF programs via this helper. 68 * Can be used from static tracepoints in the future. 69 * 70 * Return: BPF programs always return an integer which is interpreted by 71 * kprobe handler as: 72 * 0 - return from kprobe (event is filtered out) 73 * 1 - store kprobe event into ring buffer 74 * Other values are reserved and currently alias to 1 75 */ 76 unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx) 77 { 78 unsigned int ret; 79 80 if (in_nmi()) /* not supported yet */ 81 return 1; 82 83 preempt_disable(); 84 85 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { 86 /* 87 * since some bpf program is already running on this cpu, 88 * don't call into another bpf program (same or different) 89 * and don't send kprobe event into ring-buffer, 90 * so return zero here 91 */ 92 ret = 0; 93 goto out; 94 } 95 96 /* 97 * Instead of moving rcu_read_lock/rcu_dereference/rcu_read_unlock 98 * to all call sites, we did a bpf_prog_array_valid() there to check 99 * whether call->prog_array is empty or not, which is 100 * a heurisitc to speed up execution. 101 * 102 * If bpf_prog_array_valid() fetched prog_array was 103 * non-NULL, we go into trace_call_bpf() and do the actual 104 * proper rcu_dereference() under RCU lock. 105 * If it turns out that prog_array is NULL then, we bail out. 106 * For the opposite, if the bpf_prog_array_valid() fetched pointer 107 * was NULL, you'll skip the prog_array with the risk of missing 108 * out of events when it was updated in between this and the 109 * rcu_dereference() which is accepted risk. 110 */ 111 ret = BPF_PROG_RUN_ARRAY_CHECK(call->prog_array, ctx, BPF_PROG_RUN); 112 113 out: 114 __this_cpu_dec(bpf_prog_active); 115 preempt_enable(); 116 117 return ret; 118 } 119 EXPORT_SYMBOL_GPL(trace_call_bpf); 120 121 #ifdef CONFIG_BPF_KPROBE_OVERRIDE 122 BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc) 123 { 124 regs_set_return_value(regs, rc); 125 override_function_with_return(regs); 126 return 0; 127 } 128 129 static const struct bpf_func_proto bpf_override_return_proto = { 130 .func = bpf_override_return, 131 .gpl_only = true, 132 .ret_type = RET_INTEGER, 133 .arg1_type = ARG_PTR_TO_CTX, 134 .arg2_type = ARG_ANYTHING, 135 }; 136 #endif 137 138 BPF_CALL_3(bpf_probe_read, void *, dst, u32, size, const void *, unsafe_ptr) 139 { 140 int ret; 141 142 ret = security_locked_down(LOCKDOWN_BPF_READ); 143 if (ret < 0) 144 goto out; 145 146 ret = probe_kernel_read(dst, unsafe_ptr, size); 147 if (unlikely(ret < 0)) 148 out: 149 memset(dst, 0, size); 150 151 return ret; 152 } 153 154 static const struct bpf_func_proto bpf_probe_read_proto = { 155 .func = bpf_probe_read, 156 .gpl_only = true, 157 .ret_type = RET_INTEGER, 158 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 159 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 160 .arg3_type = ARG_ANYTHING, 161 }; 162 163 BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src, 164 u32, size) 165 { 166 /* 167 * Ensure we're in user context which is safe for the helper to 168 * run. This helper has no business in a kthread. 169 * 170 * access_ok() should prevent writing to non-user memory, but in 171 * some situations (nommu, temporary switch, etc) access_ok() does 172 * not provide enough validation, hence the check on KERNEL_DS. 173 * 174 * nmi_uaccess_okay() ensures the probe is not run in an interim 175 * state, when the task or mm are switched. This is specifically 176 * required to prevent the use of temporary mm. 177 */ 178 179 if (unlikely(in_interrupt() || 180 current->flags & (PF_KTHREAD | PF_EXITING))) 181 return -EPERM; 182 if (unlikely(uaccess_kernel())) 183 return -EPERM; 184 if (unlikely(!nmi_uaccess_okay())) 185 return -EPERM; 186 if (!access_ok(unsafe_ptr, size)) 187 return -EPERM; 188 189 return probe_kernel_write(unsafe_ptr, src, size); 190 } 191 192 static const struct bpf_func_proto bpf_probe_write_user_proto = { 193 .func = bpf_probe_write_user, 194 .gpl_only = true, 195 .ret_type = RET_INTEGER, 196 .arg1_type = ARG_ANYTHING, 197 .arg2_type = ARG_PTR_TO_MEM, 198 .arg3_type = ARG_CONST_SIZE, 199 }; 200 201 static const struct bpf_func_proto *bpf_get_probe_write_proto(void) 202 { 203 pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!", 204 current->comm, task_pid_nr(current)); 205 206 return &bpf_probe_write_user_proto; 207 } 208 209 /* 210 * Only limited trace_printk() conversion specifiers allowed: 211 * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %s 212 */ 213 BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, 214 u64, arg2, u64, arg3) 215 { 216 bool str_seen = false; 217 int mod[3] = {}; 218 int fmt_cnt = 0; 219 u64 unsafe_addr; 220 char buf[64]; 221 int i; 222 223 /* 224 * bpf_check()->check_func_arg()->check_stack_boundary() 225 * guarantees that fmt points to bpf program stack, 226 * fmt_size bytes of it were initialized and fmt_size > 0 227 */ 228 if (fmt[--fmt_size] != 0) 229 return -EINVAL; 230 231 /* check format string for allowed specifiers */ 232 for (i = 0; i < fmt_size; i++) { 233 if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) 234 return -EINVAL; 235 236 if (fmt[i] != '%') 237 continue; 238 239 if (fmt_cnt >= 3) 240 return -EINVAL; 241 242 /* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */ 243 i++; 244 if (fmt[i] == 'l') { 245 mod[fmt_cnt]++; 246 i++; 247 } else if (fmt[i] == 'p' || fmt[i] == 's') { 248 mod[fmt_cnt]++; 249 /* disallow any further format extensions */ 250 if (fmt[i + 1] != 0 && 251 !isspace(fmt[i + 1]) && 252 !ispunct(fmt[i + 1])) 253 return -EINVAL; 254 fmt_cnt++; 255 if (fmt[i] == 's') { 256 if (str_seen) 257 /* allow only one '%s' per fmt string */ 258 return -EINVAL; 259 str_seen = true; 260 261 switch (fmt_cnt) { 262 case 1: 263 unsafe_addr = arg1; 264 arg1 = (long) buf; 265 break; 266 case 2: 267 unsafe_addr = arg2; 268 arg2 = (long) buf; 269 break; 270 case 3: 271 unsafe_addr = arg3; 272 arg3 = (long) buf; 273 break; 274 } 275 buf[0] = 0; 276 strncpy_from_unsafe(buf, 277 (void *) (long) unsafe_addr, 278 sizeof(buf)); 279 } 280 continue; 281 } 282 283 if (fmt[i] == 'l') { 284 mod[fmt_cnt]++; 285 i++; 286 } 287 288 if (fmt[i] != 'i' && fmt[i] != 'd' && 289 fmt[i] != 'u' && fmt[i] != 'x') 290 return -EINVAL; 291 fmt_cnt++; 292 } 293 294 /* Horrid workaround for getting va_list handling working with different 295 * argument type combinations generically for 32 and 64 bit archs. 296 */ 297 #define __BPF_TP_EMIT() __BPF_ARG3_TP() 298 #define __BPF_TP(...) \ 299 __trace_printk(0 /* Fake ip */, \ 300 fmt, ##__VA_ARGS__) 301 302 #define __BPF_ARG1_TP(...) \ 303 ((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64)) \ 304 ? __BPF_TP(arg1, ##__VA_ARGS__) \ 305 : ((mod[0] == 1 || (mod[0] == 0 && __BITS_PER_LONG == 32)) \ 306 ? __BPF_TP((long)arg1, ##__VA_ARGS__) \ 307 : __BPF_TP((u32)arg1, ##__VA_ARGS__))) 308 309 #define __BPF_ARG2_TP(...) \ 310 ((mod[1] == 2 || (mod[1] == 1 && __BITS_PER_LONG == 64)) \ 311 ? __BPF_ARG1_TP(arg2, ##__VA_ARGS__) \ 312 : ((mod[1] == 1 || (mod[1] == 0 && __BITS_PER_LONG == 32)) \ 313 ? __BPF_ARG1_TP((long)arg2, ##__VA_ARGS__) \ 314 : __BPF_ARG1_TP((u32)arg2, ##__VA_ARGS__))) 315 316 #define __BPF_ARG3_TP(...) \ 317 ((mod[2] == 2 || (mod[2] == 1 && __BITS_PER_LONG == 64)) \ 318 ? __BPF_ARG2_TP(arg3, ##__VA_ARGS__) \ 319 : ((mod[2] == 1 || (mod[2] == 0 && __BITS_PER_LONG == 32)) \ 320 ? __BPF_ARG2_TP((long)arg3, ##__VA_ARGS__) \ 321 : __BPF_ARG2_TP((u32)arg3, ##__VA_ARGS__))) 322 323 return __BPF_TP_EMIT(); 324 } 325 326 static const struct bpf_func_proto bpf_trace_printk_proto = { 327 .func = bpf_trace_printk, 328 .gpl_only = true, 329 .ret_type = RET_INTEGER, 330 .arg1_type = ARG_PTR_TO_MEM, 331 .arg2_type = ARG_CONST_SIZE, 332 }; 333 334 const struct bpf_func_proto *bpf_get_trace_printk_proto(void) 335 { 336 /* 337 * this program might be calling bpf_trace_printk, 338 * so allocate per-cpu printk buffers 339 */ 340 trace_printk_init_buffers(); 341 342 return &bpf_trace_printk_proto; 343 } 344 345 static __always_inline int 346 get_map_perf_counter(struct bpf_map *map, u64 flags, 347 u64 *value, u64 *enabled, u64 *running) 348 { 349 struct bpf_array *array = container_of(map, struct bpf_array, map); 350 unsigned int cpu = smp_processor_id(); 351 u64 index = flags & BPF_F_INDEX_MASK; 352 struct bpf_event_entry *ee; 353 354 if (unlikely(flags & ~(BPF_F_INDEX_MASK))) 355 return -EINVAL; 356 if (index == BPF_F_CURRENT_CPU) 357 index = cpu; 358 if (unlikely(index >= array->map.max_entries)) 359 return -E2BIG; 360 361 ee = READ_ONCE(array->ptrs[index]); 362 if (!ee) 363 return -ENOENT; 364 365 return perf_event_read_local(ee->event, value, enabled, running); 366 } 367 368 BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags) 369 { 370 u64 value = 0; 371 int err; 372 373 err = get_map_perf_counter(map, flags, &value, NULL, NULL); 374 /* 375 * this api is ugly since we miss [-22..-2] range of valid 376 * counter values, but that's uapi 377 */ 378 if (err) 379 return err; 380 return value; 381 } 382 383 static const struct bpf_func_proto bpf_perf_event_read_proto = { 384 .func = bpf_perf_event_read, 385 .gpl_only = true, 386 .ret_type = RET_INTEGER, 387 .arg1_type = ARG_CONST_MAP_PTR, 388 .arg2_type = ARG_ANYTHING, 389 }; 390 391 BPF_CALL_4(bpf_perf_event_read_value, struct bpf_map *, map, u64, flags, 392 struct bpf_perf_event_value *, buf, u32, size) 393 { 394 int err = -EINVAL; 395 396 if (unlikely(size != sizeof(struct bpf_perf_event_value))) 397 goto clear; 398 err = get_map_perf_counter(map, flags, &buf->counter, &buf->enabled, 399 &buf->running); 400 if (unlikely(err)) 401 goto clear; 402 return 0; 403 clear: 404 memset(buf, 0, size); 405 return err; 406 } 407 408 static const struct bpf_func_proto bpf_perf_event_read_value_proto = { 409 .func = bpf_perf_event_read_value, 410 .gpl_only = true, 411 .ret_type = RET_INTEGER, 412 .arg1_type = ARG_CONST_MAP_PTR, 413 .arg2_type = ARG_ANYTHING, 414 .arg3_type = ARG_PTR_TO_UNINIT_MEM, 415 .arg4_type = ARG_CONST_SIZE, 416 }; 417 418 static __always_inline u64 419 __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map, 420 u64 flags, struct perf_sample_data *sd) 421 { 422 struct bpf_array *array = container_of(map, struct bpf_array, map); 423 unsigned int cpu = smp_processor_id(); 424 u64 index = flags & BPF_F_INDEX_MASK; 425 struct bpf_event_entry *ee; 426 struct perf_event *event; 427 428 if (index == BPF_F_CURRENT_CPU) 429 index = cpu; 430 if (unlikely(index >= array->map.max_entries)) 431 return -E2BIG; 432 433 ee = READ_ONCE(array->ptrs[index]); 434 if (!ee) 435 return -ENOENT; 436 437 event = ee->event; 438 if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE || 439 event->attr.config != PERF_COUNT_SW_BPF_OUTPUT)) 440 return -EINVAL; 441 442 if (unlikely(event->oncpu != cpu)) 443 return -EOPNOTSUPP; 444 445 return perf_event_output(event, sd, regs); 446 } 447 448 /* 449 * Support executing tracepoints in normal, irq, and nmi context that each call 450 * bpf_perf_event_output 451 */ 452 struct bpf_trace_sample_data { 453 struct perf_sample_data sds[3]; 454 }; 455 456 static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_trace_sds); 457 static DEFINE_PER_CPU(int, bpf_trace_nest_level); 458 BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map, 459 u64, flags, void *, data, u64, size) 460 { 461 struct bpf_trace_sample_data *sds = this_cpu_ptr(&bpf_trace_sds); 462 int nest_level = this_cpu_inc_return(bpf_trace_nest_level); 463 struct perf_raw_record raw = { 464 .frag = { 465 .size = size, 466 .data = data, 467 }, 468 }; 469 struct perf_sample_data *sd; 470 int err; 471 472 if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(sds->sds))) { 473 err = -EBUSY; 474 goto out; 475 } 476 477 sd = &sds->sds[nest_level - 1]; 478 479 if (unlikely(flags & ~(BPF_F_INDEX_MASK))) { 480 err = -EINVAL; 481 goto out; 482 } 483 484 perf_sample_data_init(sd, 0, 0); 485 sd->raw = &raw; 486 487 err = __bpf_perf_event_output(regs, map, flags, sd); 488 489 out: 490 this_cpu_dec(bpf_trace_nest_level); 491 return err; 492 } 493 494 static const struct bpf_func_proto bpf_perf_event_output_proto = { 495 .func = bpf_perf_event_output, 496 .gpl_only = true, 497 .ret_type = RET_INTEGER, 498 .arg1_type = ARG_PTR_TO_CTX, 499 .arg2_type = ARG_CONST_MAP_PTR, 500 .arg3_type = ARG_ANYTHING, 501 .arg4_type = ARG_PTR_TO_MEM, 502 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 503 }; 504 505 static DEFINE_PER_CPU(struct pt_regs, bpf_pt_regs); 506 static DEFINE_PER_CPU(struct perf_sample_data, bpf_misc_sd); 507 508 u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 509 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 510 { 511 struct perf_sample_data *sd = this_cpu_ptr(&bpf_misc_sd); 512 struct pt_regs *regs = this_cpu_ptr(&bpf_pt_regs); 513 struct perf_raw_frag frag = { 514 .copy = ctx_copy, 515 .size = ctx_size, 516 .data = ctx, 517 }; 518 struct perf_raw_record raw = { 519 .frag = { 520 { 521 .next = ctx_size ? &frag : NULL, 522 }, 523 .size = meta_size, 524 .data = meta, 525 }, 526 }; 527 528 perf_fetch_caller_regs(regs); 529 perf_sample_data_init(sd, 0, 0); 530 sd->raw = &raw; 531 532 return __bpf_perf_event_output(regs, map, flags, sd); 533 } 534 535 BPF_CALL_0(bpf_get_current_task) 536 { 537 return (long) current; 538 } 539 540 static const struct bpf_func_proto bpf_get_current_task_proto = { 541 .func = bpf_get_current_task, 542 .gpl_only = true, 543 .ret_type = RET_INTEGER, 544 }; 545 546 BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx) 547 { 548 struct bpf_array *array = container_of(map, struct bpf_array, map); 549 struct cgroup *cgrp; 550 551 if (unlikely(idx >= array->map.max_entries)) 552 return -E2BIG; 553 554 cgrp = READ_ONCE(array->ptrs[idx]); 555 if (unlikely(!cgrp)) 556 return -EAGAIN; 557 558 return task_under_cgroup_hierarchy(current, cgrp); 559 } 560 561 static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = { 562 .func = bpf_current_task_under_cgroup, 563 .gpl_only = false, 564 .ret_type = RET_INTEGER, 565 .arg1_type = ARG_CONST_MAP_PTR, 566 .arg2_type = ARG_ANYTHING, 567 }; 568 569 BPF_CALL_3(bpf_probe_read_str, void *, dst, u32, size, 570 const void *, unsafe_ptr) 571 { 572 int ret; 573 574 ret = security_locked_down(LOCKDOWN_BPF_READ); 575 if (ret < 0) 576 goto out; 577 578 /* 579 * The strncpy_from_unsafe() call will likely not fill the entire 580 * buffer, but that's okay in this circumstance as we're probing 581 * arbitrary memory anyway similar to bpf_probe_read() and might 582 * as well probe the stack. Thus, memory is explicitly cleared 583 * only in error case, so that improper users ignoring return 584 * code altogether don't copy garbage; otherwise length of string 585 * is returned that can be used for bpf_perf_event_output() et al. 586 */ 587 ret = strncpy_from_unsafe(dst, unsafe_ptr, size); 588 if (unlikely(ret < 0)) 589 out: 590 memset(dst, 0, size); 591 592 return ret; 593 } 594 595 static const struct bpf_func_proto bpf_probe_read_str_proto = { 596 .func = bpf_probe_read_str, 597 .gpl_only = true, 598 .ret_type = RET_INTEGER, 599 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 600 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 601 .arg3_type = ARG_ANYTHING, 602 }; 603 604 static const struct bpf_func_proto * 605 tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 606 { 607 switch (func_id) { 608 case BPF_FUNC_map_lookup_elem: 609 return &bpf_map_lookup_elem_proto; 610 case BPF_FUNC_map_update_elem: 611 return &bpf_map_update_elem_proto; 612 case BPF_FUNC_map_delete_elem: 613 return &bpf_map_delete_elem_proto; 614 case BPF_FUNC_map_push_elem: 615 return &bpf_map_push_elem_proto; 616 case BPF_FUNC_map_pop_elem: 617 return &bpf_map_pop_elem_proto; 618 case BPF_FUNC_map_peek_elem: 619 return &bpf_map_peek_elem_proto; 620 case BPF_FUNC_probe_read: 621 return &bpf_probe_read_proto; 622 case BPF_FUNC_ktime_get_ns: 623 return &bpf_ktime_get_ns_proto; 624 case BPF_FUNC_tail_call: 625 return &bpf_tail_call_proto; 626 case BPF_FUNC_get_current_pid_tgid: 627 return &bpf_get_current_pid_tgid_proto; 628 case BPF_FUNC_get_current_task: 629 return &bpf_get_current_task_proto; 630 case BPF_FUNC_get_current_uid_gid: 631 return &bpf_get_current_uid_gid_proto; 632 case BPF_FUNC_get_current_comm: 633 return &bpf_get_current_comm_proto; 634 case BPF_FUNC_trace_printk: 635 return bpf_get_trace_printk_proto(); 636 case BPF_FUNC_get_smp_processor_id: 637 return &bpf_get_smp_processor_id_proto; 638 case BPF_FUNC_get_numa_node_id: 639 return &bpf_get_numa_node_id_proto; 640 case BPF_FUNC_perf_event_read: 641 return &bpf_perf_event_read_proto; 642 case BPF_FUNC_probe_write_user: 643 return bpf_get_probe_write_proto(); 644 case BPF_FUNC_current_task_under_cgroup: 645 return &bpf_current_task_under_cgroup_proto; 646 case BPF_FUNC_get_prandom_u32: 647 return &bpf_get_prandom_u32_proto; 648 case BPF_FUNC_probe_read_str: 649 return &bpf_probe_read_str_proto; 650 #ifdef CONFIG_CGROUPS 651 case BPF_FUNC_get_current_cgroup_id: 652 return &bpf_get_current_cgroup_id_proto; 653 #endif 654 default: 655 return NULL; 656 } 657 } 658 659 static const struct bpf_func_proto * 660 kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 661 { 662 switch (func_id) { 663 case BPF_FUNC_perf_event_output: 664 return &bpf_perf_event_output_proto; 665 case BPF_FUNC_get_stackid: 666 return &bpf_get_stackid_proto; 667 case BPF_FUNC_get_stack: 668 return &bpf_get_stack_proto; 669 case BPF_FUNC_perf_event_read_value: 670 return &bpf_perf_event_read_value_proto; 671 #ifdef CONFIG_BPF_KPROBE_OVERRIDE 672 case BPF_FUNC_override_return: 673 return &bpf_override_return_proto; 674 #endif 675 default: 676 return tracing_func_proto(func_id, prog); 677 } 678 } 679 680 /* bpf+kprobe programs can access fields of 'struct pt_regs' */ 681 static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type, 682 const struct bpf_prog *prog, 683 struct bpf_insn_access_aux *info) 684 { 685 if (off < 0 || off >= sizeof(struct pt_regs)) 686 return false; 687 if (type != BPF_READ) 688 return false; 689 if (off % size != 0) 690 return false; 691 /* 692 * Assertion for 32 bit to make sure last 8 byte access 693 * (BPF_DW) to the last 4 byte member is disallowed. 694 */ 695 if (off + size > sizeof(struct pt_regs)) 696 return false; 697 698 return true; 699 } 700 701 const struct bpf_verifier_ops kprobe_verifier_ops = { 702 .get_func_proto = kprobe_prog_func_proto, 703 .is_valid_access = kprobe_prog_is_valid_access, 704 }; 705 706 const struct bpf_prog_ops kprobe_prog_ops = { 707 }; 708 709 BPF_CALL_5(bpf_perf_event_output_tp, void *, tp_buff, struct bpf_map *, map, 710 u64, flags, void *, data, u64, size) 711 { 712 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 713 714 /* 715 * r1 points to perf tracepoint buffer where first 8 bytes are hidden 716 * from bpf program and contain a pointer to 'struct pt_regs'. Fetch it 717 * from there and call the same bpf_perf_event_output() helper inline. 718 */ 719 return ____bpf_perf_event_output(regs, map, flags, data, size); 720 } 721 722 static const struct bpf_func_proto bpf_perf_event_output_proto_tp = { 723 .func = bpf_perf_event_output_tp, 724 .gpl_only = true, 725 .ret_type = RET_INTEGER, 726 .arg1_type = ARG_PTR_TO_CTX, 727 .arg2_type = ARG_CONST_MAP_PTR, 728 .arg3_type = ARG_ANYTHING, 729 .arg4_type = ARG_PTR_TO_MEM, 730 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 731 }; 732 733 BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map, 734 u64, flags) 735 { 736 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 737 738 /* 739 * Same comment as in bpf_perf_event_output_tp(), only that this time 740 * the other helper's function body cannot be inlined due to being 741 * external, thus we need to call raw helper function. 742 */ 743 return bpf_get_stackid((unsigned long) regs, (unsigned long) map, 744 flags, 0, 0); 745 } 746 747 static const struct bpf_func_proto bpf_get_stackid_proto_tp = { 748 .func = bpf_get_stackid_tp, 749 .gpl_only = true, 750 .ret_type = RET_INTEGER, 751 .arg1_type = ARG_PTR_TO_CTX, 752 .arg2_type = ARG_CONST_MAP_PTR, 753 .arg3_type = ARG_ANYTHING, 754 }; 755 756 BPF_CALL_4(bpf_get_stack_tp, void *, tp_buff, void *, buf, u32, size, 757 u64, flags) 758 { 759 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 760 761 return bpf_get_stack((unsigned long) regs, (unsigned long) buf, 762 (unsigned long) size, flags, 0); 763 } 764 765 static const struct bpf_func_proto bpf_get_stack_proto_tp = { 766 .func = bpf_get_stack_tp, 767 .gpl_only = true, 768 .ret_type = RET_INTEGER, 769 .arg1_type = ARG_PTR_TO_CTX, 770 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 771 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 772 .arg4_type = ARG_ANYTHING, 773 }; 774 775 static const struct bpf_func_proto * 776 tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 777 { 778 switch (func_id) { 779 case BPF_FUNC_perf_event_output: 780 return &bpf_perf_event_output_proto_tp; 781 case BPF_FUNC_get_stackid: 782 return &bpf_get_stackid_proto_tp; 783 case BPF_FUNC_get_stack: 784 return &bpf_get_stack_proto_tp; 785 default: 786 return tracing_func_proto(func_id, prog); 787 } 788 } 789 790 static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type, 791 const struct bpf_prog *prog, 792 struct bpf_insn_access_aux *info) 793 { 794 if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE) 795 return false; 796 if (type != BPF_READ) 797 return false; 798 if (off % size != 0) 799 return false; 800 801 BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(__u64)); 802 return true; 803 } 804 805 const struct bpf_verifier_ops tracepoint_verifier_ops = { 806 .get_func_proto = tp_prog_func_proto, 807 .is_valid_access = tp_prog_is_valid_access, 808 }; 809 810 const struct bpf_prog_ops tracepoint_prog_ops = { 811 }; 812 813 BPF_CALL_3(bpf_perf_prog_read_value, struct bpf_perf_event_data_kern *, ctx, 814 struct bpf_perf_event_value *, buf, u32, size) 815 { 816 int err = -EINVAL; 817 818 if (unlikely(size != sizeof(struct bpf_perf_event_value))) 819 goto clear; 820 err = perf_event_read_local(ctx->event, &buf->counter, &buf->enabled, 821 &buf->running); 822 if (unlikely(err)) 823 goto clear; 824 return 0; 825 clear: 826 memset(buf, 0, size); 827 return err; 828 } 829 830 static const struct bpf_func_proto bpf_perf_prog_read_value_proto = { 831 .func = bpf_perf_prog_read_value, 832 .gpl_only = true, 833 .ret_type = RET_INTEGER, 834 .arg1_type = ARG_PTR_TO_CTX, 835 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 836 .arg3_type = ARG_CONST_SIZE, 837 }; 838 839 static const struct bpf_func_proto * 840 pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 841 { 842 switch (func_id) { 843 case BPF_FUNC_perf_event_output: 844 return &bpf_perf_event_output_proto_tp; 845 case BPF_FUNC_get_stackid: 846 return &bpf_get_stackid_proto_tp; 847 case BPF_FUNC_get_stack: 848 return &bpf_get_stack_proto_tp; 849 case BPF_FUNC_perf_prog_read_value: 850 return &bpf_perf_prog_read_value_proto; 851 default: 852 return tracing_func_proto(func_id, prog); 853 } 854 } 855 856 /* 857 * bpf_raw_tp_regs are separate from bpf_pt_regs used from skb/xdp 858 * to avoid potential recursive reuse issue when/if tracepoints are added 859 * inside bpf_*_event_output, bpf_get_stackid and/or bpf_get_stack. 860 * 861 * Since raw tracepoints run despite bpf_prog_active, support concurrent usage 862 * in normal, irq, and nmi context. 863 */ 864 struct bpf_raw_tp_regs { 865 struct pt_regs regs[3]; 866 }; 867 static DEFINE_PER_CPU(struct bpf_raw_tp_regs, bpf_raw_tp_regs); 868 static DEFINE_PER_CPU(int, bpf_raw_tp_nest_level); 869 static struct pt_regs *get_bpf_raw_tp_regs(void) 870 { 871 struct bpf_raw_tp_regs *tp_regs = this_cpu_ptr(&bpf_raw_tp_regs); 872 int nest_level = this_cpu_inc_return(bpf_raw_tp_nest_level); 873 874 if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(tp_regs->regs))) { 875 this_cpu_dec(bpf_raw_tp_nest_level); 876 return ERR_PTR(-EBUSY); 877 } 878 879 return &tp_regs->regs[nest_level - 1]; 880 } 881 882 static void put_bpf_raw_tp_regs(void) 883 { 884 this_cpu_dec(bpf_raw_tp_nest_level); 885 } 886 887 BPF_CALL_5(bpf_perf_event_output_raw_tp, struct bpf_raw_tracepoint_args *, args, 888 struct bpf_map *, map, u64, flags, void *, data, u64, size) 889 { 890 struct pt_regs *regs = get_bpf_raw_tp_regs(); 891 int ret; 892 893 if (IS_ERR(regs)) 894 return PTR_ERR(regs); 895 896 perf_fetch_caller_regs(regs); 897 ret = ____bpf_perf_event_output(regs, map, flags, data, size); 898 899 put_bpf_raw_tp_regs(); 900 return ret; 901 } 902 903 static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = { 904 .func = bpf_perf_event_output_raw_tp, 905 .gpl_only = true, 906 .ret_type = RET_INTEGER, 907 .arg1_type = ARG_PTR_TO_CTX, 908 .arg2_type = ARG_CONST_MAP_PTR, 909 .arg3_type = ARG_ANYTHING, 910 .arg4_type = ARG_PTR_TO_MEM, 911 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 912 }; 913 914 BPF_CALL_3(bpf_get_stackid_raw_tp, struct bpf_raw_tracepoint_args *, args, 915 struct bpf_map *, map, u64, flags) 916 { 917 struct pt_regs *regs = get_bpf_raw_tp_regs(); 918 int ret; 919 920 if (IS_ERR(regs)) 921 return PTR_ERR(regs); 922 923 perf_fetch_caller_regs(regs); 924 /* similar to bpf_perf_event_output_tp, but pt_regs fetched differently */ 925 ret = bpf_get_stackid((unsigned long) regs, (unsigned long) map, 926 flags, 0, 0); 927 put_bpf_raw_tp_regs(); 928 return ret; 929 } 930 931 static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = { 932 .func = bpf_get_stackid_raw_tp, 933 .gpl_only = true, 934 .ret_type = RET_INTEGER, 935 .arg1_type = ARG_PTR_TO_CTX, 936 .arg2_type = ARG_CONST_MAP_PTR, 937 .arg3_type = ARG_ANYTHING, 938 }; 939 940 BPF_CALL_4(bpf_get_stack_raw_tp, struct bpf_raw_tracepoint_args *, args, 941 void *, buf, u32, size, u64, flags) 942 { 943 struct pt_regs *regs = get_bpf_raw_tp_regs(); 944 int ret; 945 946 if (IS_ERR(regs)) 947 return PTR_ERR(regs); 948 949 perf_fetch_caller_regs(regs); 950 ret = bpf_get_stack((unsigned long) regs, (unsigned long) buf, 951 (unsigned long) size, flags, 0); 952 put_bpf_raw_tp_regs(); 953 return ret; 954 } 955 956 static const struct bpf_func_proto bpf_get_stack_proto_raw_tp = { 957 .func = bpf_get_stack_raw_tp, 958 .gpl_only = true, 959 .ret_type = RET_INTEGER, 960 .arg1_type = ARG_PTR_TO_CTX, 961 .arg2_type = ARG_PTR_TO_MEM, 962 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 963 .arg4_type = ARG_ANYTHING, 964 }; 965 966 static const struct bpf_func_proto * 967 raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 968 { 969 switch (func_id) { 970 case BPF_FUNC_perf_event_output: 971 return &bpf_perf_event_output_proto_raw_tp; 972 case BPF_FUNC_get_stackid: 973 return &bpf_get_stackid_proto_raw_tp; 974 case BPF_FUNC_get_stack: 975 return &bpf_get_stack_proto_raw_tp; 976 default: 977 return tracing_func_proto(func_id, prog); 978 } 979 } 980 981 static bool raw_tp_prog_is_valid_access(int off, int size, 982 enum bpf_access_type type, 983 const struct bpf_prog *prog, 984 struct bpf_insn_access_aux *info) 985 { 986 /* largest tracepoint in the kernel has 12 args */ 987 if (off < 0 || off >= sizeof(__u64) * 12) 988 return false; 989 if (type != BPF_READ) 990 return false; 991 if (off % size != 0) 992 return false; 993 return true; 994 } 995 996 const struct bpf_verifier_ops raw_tracepoint_verifier_ops = { 997 .get_func_proto = raw_tp_prog_func_proto, 998 .is_valid_access = raw_tp_prog_is_valid_access, 999 }; 1000 1001 const struct bpf_prog_ops raw_tracepoint_prog_ops = { 1002 }; 1003 1004 static bool raw_tp_writable_prog_is_valid_access(int off, int size, 1005 enum bpf_access_type type, 1006 const struct bpf_prog *prog, 1007 struct bpf_insn_access_aux *info) 1008 { 1009 if (off == 0) { 1010 if (size != sizeof(u64) || type != BPF_READ) 1011 return false; 1012 info->reg_type = PTR_TO_TP_BUFFER; 1013 } 1014 return raw_tp_prog_is_valid_access(off, size, type, prog, info); 1015 } 1016 1017 const struct bpf_verifier_ops raw_tracepoint_writable_verifier_ops = { 1018 .get_func_proto = raw_tp_prog_func_proto, 1019 .is_valid_access = raw_tp_writable_prog_is_valid_access, 1020 }; 1021 1022 const struct bpf_prog_ops raw_tracepoint_writable_prog_ops = { 1023 }; 1024 1025 static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type, 1026 const struct bpf_prog *prog, 1027 struct bpf_insn_access_aux *info) 1028 { 1029 const int size_u64 = sizeof(u64); 1030 1031 if (off < 0 || off >= sizeof(struct bpf_perf_event_data)) 1032 return false; 1033 if (type != BPF_READ) 1034 return false; 1035 if (off % size != 0) { 1036 if (sizeof(unsigned long) != 4) 1037 return false; 1038 if (size != 8) 1039 return false; 1040 if (off % size != 4) 1041 return false; 1042 } 1043 1044 switch (off) { 1045 case bpf_ctx_range(struct bpf_perf_event_data, sample_period): 1046 bpf_ctx_record_field_size(info, size_u64); 1047 if (!bpf_ctx_narrow_access_ok(off, size, size_u64)) 1048 return false; 1049 break; 1050 case bpf_ctx_range(struct bpf_perf_event_data, addr): 1051 bpf_ctx_record_field_size(info, size_u64); 1052 if (!bpf_ctx_narrow_access_ok(off, size, size_u64)) 1053 return false; 1054 break; 1055 default: 1056 if (size != sizeof(long)) 1057 return false; 1058 } 1059 1060 return true; 1061 } 1062 1063 static u32 pe_prog_convert_ctx_access(enum bpf_access_type type, 1064 const struct bpf_insn *si, 1065 struct bpf_insn *insn_buf, 1066 struct bpf_prog *prog, u32 *target_size) 1067 { 1068 struct bpf_insn *insn = insn_buf; 1069 1070 switch (si->off) { 1071 case offsetof(struct bpf_perf_event_data, sample_period): 1072 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 1073 data), si->dst_reg, si->src_reg, 1074 offsetof(struct bpf_perf_event_data_kern, data)); 1075 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg, 1076 bpf_target_off(struct perf_sample_data, period, 8, 1077 target_size)); 1078 break; 1079 case offsetof(struct bpf_perf_event_data, addr): 1080 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 1081 data), si->dst_reg, si->src_reg, 1082 offsetof(struct bpf_perf_event_data_kern, data)); 1083 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg, 1084 bpf_target_off(struct perf_sample_data, addr, 8, 1085 target_size)); 1086 break; 1087 default: 1088 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 1089 regs), si->dst_reg, si->src_reg, 1090 offsetof(struct bpf_perf_event_data_kern, regs)); 1091 *insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), si->dst_reg, si->dst_reg, 1092 si->off); 1093 break; 1094 } 1095 1096 return insn - insn_buf; 1097 } 1098 1099 const struct bpf_verifier_ops perf_event_verifier_ops = { 1100 .get_func_proto = pe_prog_func_proto, 1101 .is_valid_access = pe_prog_is_valid_access, 1102 .convert_ctx_access = pe_prog_convert_ctx_access, 1103 }; 1104 1105 const struct bpf_prog_ops perf_event_prog_ops = { 1106 }; 1107 1108 static DEFINE_MUTEX(bpf_event_mutex); 1109 1110 #define BPF_TRACE_MAX_PROGS 64 1111 1112 int perf_event_attach_bpf_prog(struct perf_event *event, 1113 struct bpf_prog *prog) 1114 { 1115 struct bpf_prog_array __rcu *old_array; 1116 struct bpf_prog_array *new_array; 1117 int ret = -EEXIST; 1118 1119 /* 1120 * Kprobe override only works if they are on the function entry, 1121 * and only if they are on the opt-in list. 1122 */ 1123 if (prog->kprobe_override && 1124 (!trace_kprobe_on_func_entry(event->tp_event) || 1125 !trace_kprobe_error_injectable(event->tp_event))) 1126 return -EINVAL; 1127 1128 mutex_lock(&bpf_event_mutex); 1129 1130 if (event->prog) 1131 goto unlock; 1132 1133 old_array = event->tp_event->prog_array; 1134 if (old_array && 1135 bpf_prog_array_length(old_array) >= BPF_TRACE_MAX_PROGS) { 1136 ret = -E2BIG; 1137 goto unlock; 1138 } 1139 1140 ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array); 1141 if (ret < 0) 1142 goto unlock; 1143 1144 /* set the new array to event->tp_event and set event->prog */ 1145 event->prog = prog; 1146 rcu_assign_pointer(event->tp_event->prog_array, new_array); 1147 bpf_prog_array_free(old_array); 1148 1149 unlock: 1150 mutex_unlock(&bpf_event_mutex); 1151 return ret; 1152 } 1153 1154 void perf_event_detach_bpf_prog(struct perf_event *event) 1155 { 1156 struct bpf_prog_array __rcu *old_array; 1157 struct bpf_prog_array *new_array; 1158 int ret; 1159 1160 mutex_lock(&bpf_event_mutex); 1161 1162 if (!event->prog) 1163 goto unlock; 1164 1165 old_array = event->tp_event->prog_array; 1166 ret = bpf_prog_array_copy(old_array, event->prog, NULL, &new_array); 1167 if (ret == -ENOENT) 1168 goto unlock; 1169 if (ret < 0) { 1170 bpf_prog_array_delete_safe(old_array, event->prog); 1171 } else { 1172 rcu_assign_pointer(event->tp_event->prog_array, new_array); 1173 bpf_prog_array_free(old_array); 1174 } 1175 1176 bpf_prog_put(event->prog); 1177 event->prog = NULL; 1178 1179 unlock: 1180 mutex_unlock(&bpf_event_mutex); 1181 } 1182 1183 int perf_event_query_prog_array(struct perf_event *event, void __user *info) 1184 { 1185 struct perf_event_query_bpf __user *uquery = info; 1186 struct perf_event_query_bpf query = {}; 1187 u32 *ids, prog_cnt, ids_len; 1188 int ret; 1189 1190 if (!capable(CAP_SYS_ADMIN)) 1191 return -EPERM; 1192 if (event->attr.type != PERF_TYPE_TRACEPOINT) 1193 return -EINVAL; 1194 if (copy_from_user(&query, uquery, sizeof(query))) 1195 return -EFAULT; 1196 1197 ids_len = query.ids_len; 1198 if (ids_len > BPF_TRACE_MAX_PROGS) 1199 return -E2BIG; 1200 ids = kcalloc(ids_len, sizeof(u32), GFP_USER | __GFP_NOWARN); 1201 if (!ids) 1202 return -ENOMEM; 1203 /* 1204 * The above kcalloc returns ZERO_SIZE_PTR when ids_len = 0, which 1205 * is required when user only wants to check for uquery->prog_cnt. 1206 * There is no need to check for it since the case is handled 1207 * gracefully in bpf_prog_array_copy_info. 1208 */ 1209 1210 mutex_lock(&bpf_event_mutex); 1211 ret = bpf_prog_array_copy_info(event->tp_event->prog_array, 1212 ids, 1213 ids_len, 1214 &prog_cnt); 1215 mutex_unlock(&bpf_event_mutex); 1216 1217 if (copy_to_user(&uquery->prog_cnt, &prog_cnt, sizeof(prog_cnt)) || 1218 copy_to_user(uquery->ids, ids, ids_len * sizeof(u32))) 1219 ret = -EFAULT; 1220 1221 kfree(ids); 1222 return ret; 1223 } 1224 1225 extern struct bpf_raw_event_map __start__bpf_raw_tp[]; 1226 extern struct bpf_raw_event_map __stop__bpf_raw_tp[]; 1227 1228 struct bpf_raw_event_map *bpf_get_raw_tracepoint(const char *name) 1229 { 1230 struct bpf_raw_event_map *btp = __start__bpf_raw_tp; 1231 1232 for (; btp < __stop__bpf_raw_tp; btp++) { 1233 if (!strcmp(btp->tp->name, name)) 1234 return btp; 1235 } 1236 1237 return bpf_get_raw_tracepoint_module(name); 1238 } 1239 1240 void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp) 1241 { 1242 struct module *mod = __module_address((unsigned long)btp); 1243 1244 if (mod) 1245 module_put(mod); 1246 } 1247 1248 static __always_inline 1249 void __bpf_trace_run(struct bpf_prog *prog, u64 *args) 1250 { 1251 rcu_read_lock(); 1252 preempt_disable(); 1253 (void) BPF_PROG_RUN(prog, args); 1254 preempt_enable(); 1255 rcu_read_unlock(); 1256 } 1257 1258 #define UNPACK(...) __VA_ARGS__ 1259 #define REPEAT_1(FN, DL, X, ...) FN(X) 1260 #define REPEAT_2(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_1(FN, DL, __VA_ARGS__) 1261 #define REPEAT_3(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_2(FN, DL, __VA_ARGS__) 1262 #define REPEAT_4(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_3(FN, DL, __VA_ARGS__) 1263 #define REPEAT_5(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_4(FN, DL, __VA_ARGS__) 1264 #define REPEAT_6(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_5(FN, DL, __VA_ARGS__) 1265 #define REPEAT_7(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_6(FN, DL, __VA_ARGS__) 1266 #define REPEAT_8(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_7(FN, DL, __VA_ARGS__) 1267 #define REPEAT_9(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_8(FN, DL, __VA_ARGS__) 1268 #define REPEAT_10(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_9(FN, DL, __VA_ARGS__) 1269 #define REPEAT_11(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_10(FN, DL, __VA_ARGS__) 1270 #define REPEAT_12(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_11(FN, DL, __VA_ARGS__) 1271 #define REPEAT(X, FN, DL, ...) REPEAT_##X(FN, DL, __VA_ARGS__) 1272 1273 #define SARG(X) u64 arg##X 1274 #define COPY(X) args[X] = arg##X 1275 1276 #define __DL_COM (,) 1277 #define __DL_SEM (;) 1278 1279 #define __SEQ_0_11 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 1280 1281 #define BPF_TRACE_DEFN_x(x) \ 1282 void bpf_trace_run##x(struct bpf_prog *prog, \ 1283 REPEAT(x, SARG, __DL_COM, __SEQ_0_11)) \ 1284 { \ 1285 u64 args[x]; \ 1286 REPEAT(x, COPY, __DL_SEM, __SEQ_0_11); \ 1287 __bpf_trace_run(prog, args); \ 1288 } \ 1289 EXPORT_SYMBOL_GPL(bpf_trace_run##x) 1290 BPF_TRACE_DEFN_x(1); 1291 BPF_TRACE_DEFN_x(2); 1292 BPF_TRACE_DEFN_x(3); 1293 BPF_TRACE_DEFN_x(4); 1294 BPF_TRACE_DEFN_x(5); 1295 BPF_TRACE_DEFN_x(6); 1296 BPF_TRACE_DEFN_x(7); 1297 BPF_TRACE_DEFN_x(8); 1298 BPF_TRACE_DEFN_x(9); 1299 BPF_TRACE_DEFN_x(10); 1300 BPF_TRACE_DEFN_x(11); 1301 BPF_TRACE_DEFN_x(12); 1302 1303 static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 1304 { 1305 struct tracepoint *tp = btp->tp; 1306 1307 /* 1308 * check that program doesn't access arguments beyond what's 1309 * available in this tracepoint 1310 */ 1311 if (prog->aux->max_ctx_offset > btp->num_args * sizeof(u64)) 1312 return -EINVAL; 1313 1314 if (prog->aux->max_tp_access > btp->writable_size) 1315 return -EINVAL; 1316 1317 return tracepoint_probe_register(tp, (void *)btp->bpf_func, prog); 1318 } 1319 1320 int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 1321 { 1322 return __bpf_probe_register(btp, prog); 1323 } 1324 1325 int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 1326 { 1327 return tracepoint_probe_unregister(btp->tp, (void *)btp->bpf_func, prog); 1328 } 1329 1330 int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id, 1331 u32 *fd_type, const char **buf, 1332 u64 *probe_offset, u64 *probe_addr) 1333 { 1334 bool is_tracepoint, is_syscall_tp; 1335 struct bpf_prog *prog; 1336 int flags, err = 0; 1337 1338 prog = event->prog; 1339 if (!prog) 1340 return -ENOENT; 1341 1342 /* not supporting BPF_PROG_TYPE_PERF_EVENT yet */ 1343 if (prog->type == BPF_PROG_TYPE_PERF_EVENT) 1344 return -EOPNOTSUPP; 1345 1346 *prog_id = prog->aux->id; 1347 flags = event->tp_event->flags; 1348 is_tracepoint = flags & TRACE_EVENT_FL_TRACEPOINT; 1349 is_syscall_tp = is_syscall_trace_event(event->tp_event); 1350 1351 if (is_tracepoint || is_syscall_tp) { 1352 *buf = is_tracepoint ? event->tp_event->tp->name 1353 : event->tp_event->name; 1354 *fd_type = BPF_FD_TYPE_TRACEPOINT; 1355 *probe_offset = 0x0; 1356 *probe_addr = 0x0; 1357 } else { 1358 /* kprobe/uprobe */ 1359 err = -EOPNOTSUPP; 1360 #ifdef CONFIG_KPROBE_EVENTS 1361 if (flags & TRACE_EVENT_FL_KPROBE) 1362 err = bpf_get_kprobe_info(event, fd_type, buf, 1363 probe_offset, probe_addr, 1364 event->attr.type == PERF_TYPE_TRACEPOINT); 1365 #endif 1366 #ifdef CONFIG_UPROBE_EVENTS 1367 if (flags & TRACE_EVENT_FL_UPROBE) 1368 err = bpf_get_uprobe_info(event, fd_type, buf, 1369 probe_offset, 1370 event->attr.type == PERF_TYPE_TRACEPOINT); 1371 #endif 1372 } 1373 1374 return err; 1375 } 1376 1377 #ifdef CONFIG_MODULES 1378 static int bpf_event_notify(struct notifier_block *nb, unsigned long op, 1379 void *module) 1380 { 1381 struct bpf_trace_module *btm, *tmp; 1382 struct module *mod = module; 1383 1384 if (mod->num_bpf_raw_events == 0 || 1385 (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING)) 1386 return 0; 1387 1388 mutex_lock(&bpf_module_mutex); 1389 1390 switch (op) { 1391 case MODULE_STATE_COMING: 1392 btm = kzalloc(sizeof(*btm), GFP_KERNEL); 1393 if (btm) { 1394 btm->module = module; 1395 list_add(&btm->list, &bpf_trace_modules); 1396 } 1397 break; 1398 case MODULE_STATE_GOING: 1399 list_for_each_entry_safe(btm, tmp, &bpf_trace_modules, list) { 1400 if (btm->module == module) { 1401 list_del(&btm->list); 1402 kfree(btm); 1403 break; 1404 } 1405 } 1406 break; 1407 } 1408 1409 mutex_unlock(&bpf_module_mutex); 1410 1411 return 0; 1412 } 1413 1414 static struct notifier_block bpf_module_nb = { 1415 .notifier_call = bpf_event_notify, 1416 }; 1417 1418 static int __init bpf_event_init(void) 1419 { 1420 register_module_notifier(&bpf_module_nb); 1421 return 0; 1422 } 1423 1424 fs_initcall(bpf_event_init); 1425 #endif /* CONFIG_MODULES */ 1426