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 #define bpf_event_rcu_dereference(p) \ 23 rcu_dereference_protected(p, lockdep_is_held(&bpf_event_mutex)) 24 25 #ifdef CONFIG_MODULES 26 struct bpf_trace_module { 27 struct module *module; 28 struct list_head list; 29 }; 30 31 static LIST_HEAD(bpf_trace_modules); 32 static DEFINE_MUTEX(bpf_module_mutex); 33 34 static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name) 35 { 36 struct bpf_raw_event_map *btp, *ret = NULL; 37 struct bpf_trace_module *btm; 38 unsigned int i; 39 40 mutex_lock(&bpf_module_mutex); 41 list_for_each_entry(btm, &bpf_trace_modules, list) { 42 for (i = 0; i < btm->module->num_bpf_raw_events; ++i) { 43 btp = &btm->module->bpf_raw_events[i]; 44 if (!strcmp(btp->tp->name, name)) { 45 if (try_module_get(btm->module)) 46 ret = btp; 47 goto out; 48 } 49 } 50 } 51 out: 52 mutex_unlock(&bpf_module_mutex); 53 return ret; 54 } 55 #else 56 static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name) 57 { 58 return NULL; 59 } 60 #endif /* CONFIG_MODULES */ 61 62 u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 63 u64 bpf_get_stack(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 64 65 /** 66 * trace_call_bpf - invoke BPF program 67 * @call: tracepoint event 68 * @ctx: opaque context pointer 69 * 70 * kprobe handlers execute BPF programs via this helper. 71 * Can be used from static tracepoints in the future. 72 * 73 * Return: BPF programs always return an integer which is interpreted by 74 * kprobe handler as: 75 * 0 - return from kprobe (event is filtered out) 76 * 1 - store kprobe event into ring buffer 77 * Other values are reserved and currently alias to 1 78 */ 79 unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx) 80 { 81 unsigned int ret; 82 83 if (in_nmi()) /* not supported yet */ 84 return 1; 85 86 preempt_disable(); 87 88 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { 89 /* 90 * since some bpf program is already running on this cpu, 91 * don't call into another bpf program (same or different) 92 * and don't send kprobe event into ring-buffer, 93 * so return zero here 94 */ 95 ret = 0; 96 goto out; 97 } 98 99 /* 100 * Instead of moving rcu_read_lock/rcu_dereference/rcu_read_unlock 101 * to all call sites, we did a bpf_prog_array_valid() there to check 102 * whether call->prog_array is empty or not, which is 103 * a heurisitc to speed up execution. 104 * 105 * If bpf_prog_array_valid() fetched prog_array was 106 * non-NULL, we go into trace_call_bpf() and do the actual 107 * proper rcu_dereference() under RCU lock. 108 * If it turns out that prog_array is NULL then, we bail out. 109 * For the opposite, if the bpf_prog_array_valid() fetched pointer 110 * was NULL, you'll skip the prog_array with the risk of missing 111 * out of events when it was updated in between this and the 112 * rcu_dereference() which is accepted risk. 113 */ 114 ret = BPF_PROG_RUN_ARRAY_CHECK(call->prog_array, ctx, BPF_PROG_RUN); 115 116 out: 117 __this_cpu_dec(bpf_prog_active); 118 preempt_enable(); 119 120 return ret; 121 } 122 EXPORT_SYMBOL_GPL(trace_call_bpf); 123 124 #ifdef CONFIG_BPF_KPROBE_OVERRIDE 125 BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc) 126 { 127 regs_set_return_value(regs, rc); 128 override_function_with_return(regs); 129 return 0; 130 } 131 132 static const struct bpf_func_proto bpf_override_return_proto = { 133 .func = bpf_override_return, 134 .gpl_only = true, 135 .ret_type = RET_INTEGER, 136 .arg1_type = ARG_PTR_TO_CTX, 137 .arg2_type = ARG_ANYTHING, 138 }; 139 #endif 140 141 BPF_CALL_3(bpf_probe_read, void *, dst, u32, size, const void *, unsafe_ptr) 142 { 143 int ret; 144 145 ret = probe_kernel_read(dst, unsafe_ptr, size); 146 if (unlikely(ret < 0)) 147 memset(dst, 0, size); 148 149 return ret; 150 } 151 152 static const struct bpf_func_proto bpf_probe_read_proto = { 153 .func = bpf_probe_read, 154 .gpl_only = true, 155 .ret_type = RET_INTEGER, 156 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 157 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 158 .arg3_type = ARG_ANYTHING, 159 }; 160 161 BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src, 162 u32, size) 163 { 164 /* 165 * Ensure we're in user context which is safe for the helper to 166 * run. This helper has no business in a kthread. 167 * 168 * access_ok() should prevent writing to non-user memory, but in 169 * some situations (nommu, temporary switch, etc) access_ok() does 170 * not provide enough validation, hence the check on KERNEL_DS. 171 * 172 * nmi_uaccess_okay() ensures the probe is not run in an interim 173 * state, when the task or mm are switched. This is specifically 174 * required to prevent the use of temporary mm. 175 */ 176 177 if (unlikely(in_interrupt() || 178 current->flags & (PF_KTHREAD | PF_EXITING))) 179 return -EPERM; 180 if (unlikely(uaccess_kernel())) 181 return -EPERM; 182 if (unlikely(!nmi_uaccess_okay())) 183 return -EPERM; 184 if (!access_ok(unsafe_ptr, size)) 185 return -EPERM; 186 187 return probe_kernel_write(unsafe_ptr, src, size); 188 } 189 190 static const struct bpf_func_proto bpf_probe_write_user_proto = { 191 .func = bpf_probe_write_user, 192 .gpl_only = true, 193 .ret_type = RET_INTEGER, 194 .arg1_type = ARG_ANYTHING, 195 .arg2_type = ARG_PTR_TO_MEM, 196 .arg3_type = ARG_CONST_SIZE, 197 }; 198 199 static const struct bpf_func_proto *bpf_get_probe_write_proto(void) 200 { 201 pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!", 202 current->comm, task_pid_nr(current)); 203 204 return &bpf_probe_write_user_proto; 205 } 206 207 /* 208 * Only limited trace_printk() conversion specifiers allowed: 209 * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %s 210 */ 211 BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, 212 u64, arg2, u64, arg3) 213 { 214 bool str_seen = false; 215 int mod[3] = {}; 216 int fmt_cnt = 0; 217 u64 unsafe_addr; 218 char buf[64]; 219 int i; 220 221 /* 222 * bpf_check()->check_func_arg()->check_stack_boundary() 223 * guarantees that fmt points to bpf program stack, 224 * fmt_size bytes of it were initialized and fmt_size > 0 225 */ 226 if (fmt[--fmt_size] != 0) 227 return -EINVAL; 228 229 /* check format string for allowed specifiers */ 230 for (i = 0; i < fmt_size; i++) { 231 if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) 232 return -EINVAL; 233 234 if (fmt[i] != '%') 235 continue; 236 237 if (fmt_cnt >= 3) 238 return -EINVAL; 239 240 /* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */ 241 i++; 242 if (fmt[i] == 'l') { 243 mod[fmt_cnt]++; 244 i++; 245 } else if (fmt[i] == 'p' || fmt[i] == 's') { 246 mod[fmt_cnt]++; 247 /* disallow any further format extensions */ 248 if (fmt[i + 1] != 0 && 249 !isspace(fmt[i + 1]) && 250 !ispunct(fmt[i + 1])) 251 return -EINVAL; 252 fmt_cnt++; 253 if (fmt[i] == 's') { 254 if (str_seen) 255 /* allow only one '%s' per fmt string */ 256 return -EINVAL; 257 str_seen = true; 258 259 switch (fmt_cnt) { 260 case 1: 261 unsafe_addr = arg1; 262 arg1 = (long) buf; 263 break; 264 case 2: 265 unsafe_addr = arg2; 266 arg2 = (long) buf; 267 break; 268 case 3: 269 unsafe_addr = arg3; 270 arg3 = (long) buf; 271 break; 272 } 273 buf[0] = 0; 274 strncpy_from_unsafe(buf, 275 (void *) (long) unsafe_addr, 276 sizeof(buf)); 277 } 278 continue; 279 } 280 281 if (fmt[i] == 'l') { 282 mod[fmt_cnt]++; 283 i++; 284 } 285 286 if (fmt[i] != 'i' && fmt[i] != 'd' && 287 fmt[i] != 'u' && fmt[i] != 'x') 288 return -EINVAL; 289 fmt_cnt++; 290 } 291 292 /* Horrid workaround for getting va_list handling working with different 293 * argument type combinations generically for 32 and 64 bit archs. 294 */ 295 #define __BPF_TP_EMIT() __BPF_ARG3_TP() 296 #define __BPF_TP(...) \ 297 __trace_printk(0 /* Fake ip */, \ 298 fmt, ##__VA_ARGS__) 299 300 #define __BPF_ARG1_TP(...) \ 301 ((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64)) \ 302 ? __BPF_TP(arg1, ##__VA_ARGS__) \ 303 : ((mod[0] == 1 || (mod[0] == 0 && __BITS_PER_LONG == 32)) \ 304 ? __BPF_TP((long)arg1, ##__VA_ARGS__) \ 305 : __BPF_TP((u32)arg1, ##__VA_ARGS__))) 306 307 #define __BPF_ARG2_TP(...) \ 308 ((mod[1] == 2 || (mod[1] == 1 && __BITS_PER_LONG == 64)) \ 309 ? __BPF_ARG1_TP(arg2, ##__VA_ARGS__) \ 310 : ((mod[1] == 1 || (mod[1] == 0 && __BITS_PER_LONG == 32)) \ 311 ? __BPF_ARG1_TP((long)arg2, ##__VA_ARGS__) \ 312 : __BPF_ARG1_TP((u32)arg2, ##__VA_ARGS__))) 313 314 #define __BPF_ARG3_TP(...) \ 315 ((mod[2] == 2 || (mod[2] == 1 && __BITS_PER_LONG == 64)) \ 316 ? __BPF_ARG2_TP(arg3, ##__VA_ARGS__) \ 317 : ((mod[2] == 1 || (mod[2] == 0 && __BITS_PER_LONG == 32)) \ 318 ? __BPF_ARG2_TP((long)arg3, ##__VA_ARGS__) \ 319 : __BPF_ARG2_TP((u32)arg3, ##__VA_ARGS__))) 320 321 return __BPF_TP_EMIT(); 322 } 323 324 static const struct bpf_func_proto bpf_trace_printk_proto = { 325 .func = bpf_trace_printk, 326 .gpl_only = true, 327 .ret_type = RET_INTEGER, 328 .arg1_type = ARG_PTR_TO_MEM, 329 .arg2_type = ARG_CONST_SIZE, 330 }; 331 332 const struct bpf_func_proto *bpf_get_trace_printk_proto(void) 333 { 334 /* 335 * this program might be calling bpf_trace_printk, 336 * so allocate per-cpu printk buffers 337 */ 338 trace_printk_init_buffers(); 339 340 return &bpf_trace_printk_proto; 341 } 342 343 static __always_inline int 344 get_map_perf_counter(struct bpf_map *map, u64 flags, 345 u64 *value, u64 *enabled, u64 *running) 346 { 347 struct bpf_array *array = container_of(map, struct bpf_array, map); 348 unsigned int cpu = smp_processor_id(); 349 u64 index = flags & BPF_F_INDEX_MASK; 350 struct bpf_event_entry *ee; 351 352 if (unlikely(flags & ~(BPF_F_INDEX_MASK))) 353 return -EINVAL; 354 if (index == BPF_F_CURRENT_CPU) 355 index = cpu; 356 if (unlikely(index >= array->map.max_entries)) 357 return -E2BIG; 358 359 ee = READ_ONCE(array->ptrs[index]); 360 if (!ee) 361 return -ENOENT; 362 363 return perf_event_read_local(ee->event, value, enabled, running); 364 } 365 366 BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags) 367 { 368 u64 value = 0; 369 int err; 370 371 err = get_map_perf_counter(map, flags, &value, NULL, NULL); 372 /* 373 * this api is ugly since we miss [-22..-2] range of valid 374 * counter values, but that's uapi 375 */ 376 if (err) 377 return err; 378 return value; 379 } 380 381 static const struct bpf_func_proto bpf_perf_event_read_proto = { 382 .func = bpf_perf_event_read, 383 .gpl_only = true, 384 .ret_type = RET_INTEGER, 385 .arg1_type = ARG_CONST_MAP_PTR, 386 .arg2_type = ARG_ANYTHING, 387 }; 388 389 BPF_CALL_4(bpf_perf_event_read_value, struct bpf_map *, map, u64, flags, 390 struct bpf_perf_event_value *, buf, u32, size) 391 { 392 int err = -EINVAL; 393 394 if (unlikely(size != sizeof(struct bpf_perf_event_value))) 395 goto clear; 396 err = get_map_perf_counter(map, flags, &buf->counter, &buf->enabled, 397 &buf->running); 398 if (unlikely(err)) 399 goto clear; 400 return 0; 401 clear: 402 memset(buf, 0, size); 403 return err; 404 } 405 406 static const struct bpf_func_proto bpf_perf_event_read_value_proto = { 407 .func = bpf_perf_event_read_value, 408 .gpl_only = true, 409 .ret_type = RET_INTEGER, 410 .arg1_type = ARG_CONST_MAP_PTR, 411 .arg2_type = ARG_ANYTHING, 412 .arg3_type = ARG_PTR_TO_UNINIT_MEM, 413 .arg4_type = ARG_CONST_SIZE, 414 }; 415 416 static __always_inline u64 417 __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map, 418 u64 flags, struct perf_sample_data *sd) 419 { 420 struct bpf_array *array = container_of(map, struct bpf_array, map); 421 unsigned int cpu = smp_processor_id(); 422 u64 index = flags & BPF_F_INDEX_MASK; 423 struct bpf_event_entry *ee; 424 struct perf_event *event; 425 426 if (index == BPF_F_CURRENT_CPU) 427 index = cpu; 428 if (unlikely(index >= array->map.max_entries)) 429 return -E2BIG; 430 431 ee = READ_ONCE(array->ptrs[index]); 432 if (!ee) 433 return -ENOENT; 434 435 event = ee->event; 436 if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE || 437 event->attr.config != PERF_COUNT_SW_BPF_OUTPUT)) 438 return -EINVAL; 439 440 if (unlikely(event->oncpu != cpu)) 441 return -EOPNOTSUPP; 442 443 return perf_event_output(event, sd, regs); 444 } 445 446 /* 447 * Support executing tracepoints in normal, irq, and nmi context that each call 448 * bpf_perf_event_output 449 */ 450 struct bpf_trace_sample_data { 451 struct perf_sample_data sds[3]; 452 }; 453 454 static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_trace_sds); 455 static DEFINE_PER_CPU(int, bpf_trace_nest_level); 456 BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map, 457 u64, flags, void *, data, u64, size) 458 { 459 struct bpf_trace_sample_data *sds = this_cpu_ptr(&bpf_trace_sds); 460 int nest_level = this_cpu_inc_return(bpf_trace_nest_level); 461 struct perf_raw_record raw = { 462 .frag = { 463 .size = size, 464 .data = data, 465 }, 466 }; 467 struct perf_sample_data *sd; 468 int err; 469 470 if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(sds->sds))) { 471 err = -EBUSY; 472 goto out; 473 } 474 475 sd = &sds->sds[nest_level - 1]; 476 477 if (unlikely(flags & ~(BPF_F_INDEX_MASK))) { 478 err = -EINVAL; 479 goto out; 480 } 481 482 perf_sample_data_init(sd, 0, 0); 483 sd->raw = &raw; 484 485 err = __bpf_perf_event_output(regs, map, flags, sd); 486 487 out: 488 this_cpu_dec(bpf_trace_nest_level); 489 return err; 490 } 491 492 static const struct bpf_func_proto bpf_perf_event_output_proto = { 493 .func = bpf_perf_event_output, 494 .gpl_only = true, 495 .ret_type = RET_INTEGER, 496 .arg1_type = ARG_PTR_TO_CTX, 497 .arg2_type = ARG_CONST_MAP_PTR, 498 .arg3_type = ARG_ANYTHING, 499 .arg4_type = ARG_PTR_TO_MEM, 500 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 501 }; 502 503 static DEFINE_PER_CPU(struct pt_regs, bpf_pt_regs); 504 static DEFINE_PER_CPU(struct perf_sample_data, bpf_misc_sd); 505 506 u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 507 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 508 { 509 struct perf_sample_data *sd = this_cpu_ptr(&bpf_misc_sd); 510 struct pt_regs *regs = this_cpu_ptr(&bpf_pt_regs); 511 struct perf_raw_frag frag = { 512 .copy = ctx_copy, 513 .size = ctx_size, 514 .data = ctx, 515 }; 516 struct perf_raw_record raw = { 517 .frag = { 518 { 519 .next = ctx_size ? &frag : NULL, 520 }, 521 .size = meta_size, 522 .data = meta, 523 }, 524 }; 525 526 perf_fetch_caller_regs(regs); 527 perf_sample_data_init(sd, 0, 0); 528 sd->raw = &raw; 529 530 return __bpf_perf_event_output(regs, map, flags, sd); 531 } 532 533 BPF_CALL_0(bpf_get_current_task) 534 { 535 return (long) current; 536 } 537 538 static const struct bpf_func_proto bpf_get_current_task_proto = { 539 .func = bpf_get_current_task, 540 .gpl_only = true, 541 .ret_type = RET_INTEGER, 542 }; 543 544 BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx) 545 { 546 struct bpf_array *array = container_of(map, struct bpf_array, map); 547 struct cgroup *cgrp; 548 549 if (unlikely(idx >= array->map.max_entries)) 550 return -E2BIG; 551 552 cgrp = READ_ONCE(array->ptrs[idx]); 553 if (unlikely(!cgrp)) 554 return -EAGAIN; 555 556 return task_under_cgroup_hierarchy(current, cgrp); 557 } 558 559 static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = { 560 .func = bpf_current_task_under_cgroup, 561 .gpl_only = false, 562 .ret_type = RET_INTEGER, 563 .arg1_type = ARG_CONST_MAP_PTR, 564 .arg2_type = ARG_ANYTHING, 565 }; 566 567 BPF_CALL_3(bpf_probe_read_str, void *, dst, u32, size, 568 const void *, unsafe_ptr) 569 { 570 int ret; 571 572 /* 573 * The strncpy_from_unsafe() call will likely not fill the entire 574 * buffer, but that's okay in this circumstance as we're probing 575 * arbitrary memory anyway similar to bpf_probe_read() and might 576 * as well probe the stack. Thus, memory is explicitly cleared 577 * only in error case, so that improper users ignoring return 578 * code altogether don't copy garbage; otherwise length of string 579 * is returned that can be used for bpf_perf_event_output() et al. 580 */ 581 ret = strncpy_from_unsafe(dst, unsafe_ptr, size); 582 if (unlikely(ret < 0)) 583 memset(dst, 0, size); 584 585 return ret; 586 } 587 588 static const struct bpf_func_proto bpf_probe_read_str_proto = { 589 .func = bpf_probe_read_str, 590 .gpl_only = true, 591 .ret_type = RET_INTEGER, 592 .arg1_type = ARG_PTR_TO_UNINIT_MEM, 593 .arg2_type = ARG_CONST_SIZE_OR_ZERO, 594 .arg3_type = ARG_ANYTHING, 595 }; 596 597 struct send_signal_irq_work { 598 struct irq_work irq_work; 599 struct task_struct *task; 600 u32 sig; 601 }; 602 603 static DEFINE_PER_CPU(struct send_signal_irq_work, send_signal_work); 604 605 static void do_bpf_send_signal(struct irq_work *entry) 606 { 607 struct send_signal_irq_work *work; 608 609 work = container_of(entry, struct send_signal_irq_work, irq_work); 610 group_send_sig_info(work->sig, SEND_SIG_PRIV, work->task, PIDTYPE_TGID); 611 } 612 613 BPF_CALL_1(bpf_send_signal, u32, sig) 614 { 615 struct send_signal_irq_work *work = NULL; 616 617 /* Similar to bpf_probe_write_user, task needs to be 618 * in a sound condition and kernel memory access be 619 * permitted in order to send signal to the current 620 * task. 621 */ 622 if (unlikely(current->flags & (PF_KTHREAD | PF_EXITING))) 623 return -EPERM; 624 if (unlikely(uaccess_kernel())) 625 return -EPERM; 626 if (unlikely(!nmi_uaccess_okay())) 627 return -EPERM; 628 629 if (in_nmi()) { 630 /* Do an early check on signal validity. Otherwise, 631 * the error is lost in deferred irq_work. 632 */ 633 if (unlikely(!valid_signal(sig))) 634 return -EINVAL; 635 636 work = this_cpu_ptr(&send_signal_work); 637 if (work->irq_work.flags & IRQ_WORK_BUSY) 638 return -EBUSY; 639 640 /* Add the current task, which is the target of sending signal, 641 * to the irq_work. The current task may change when queued 642 * irq works get executed. 643 */ 644 work->task = current; 645 work->sig = sig; 646 irq_work_queue(&work->irq_work); 647 return 0; 648 } 649 650 return group_send_sig_info(sig, SEND_SIG_PRIV, current, PIDTYPE_TGID); 651 } 652 653 static const struct bpf_func_proto bpf_send_signal_proto = { 654 .func = bpf_send_signal, 655 .gpl_only = false, 656 .ret_type = RET_INTEGER, 657 .arg1_type = ARG_ANYTHING, 658 }; 659 660 static const struct bpf_func_proto * 661 tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 662 { 663 switch (func_id) { 664 case BPF_FUNC_map_lookup_elem: 665 return &bpf_map_lookup_elem_proto; 666 case BPF_FUNC_map_update_elem: 667 return &bpf_map_update_elem_proto; 668 case BPF_FUNC_map_delete_elem: 669 return &bpf_map_delete_elem_proto; 670 case BPF_FUNC_map_push_elem: 671 return &bpf_map_push_elem_proto; 672 case BPF_FUNC_map_pop_elem: 673 return &bpf_map_pop_elem_proto; 674 case BPF_FUNC_map_peek_elem: 675 return &bpf_map_peek_elem_proto; 676 case BPF_FUNC_probe_read: 677 return &bpf_probe_read_proto; 678 case BPF_FUNC_ktime_get_ns: 679 return &bpf_ktime_get_ns_proto; 680 case BPF_FUNC_tail_call: 681 return &bpf_tail_call_proto; 682 case BPF_FUNC_get_current_pid_tgid: 683 return &bpf_get_current_pid_tgid_proto; 684 case BPF_FUNC_get_current_task: 685 return &bpf_get_current_task_proto; 686 case BPF_FUNC_get_current_uid_gid: 687 return &bpf_get_current_uid_gid_proto; 688 case BPF_FUNC_get_current_comm: 689 return &bpf_get_current_comm_proto; 690 case BPF_FUNC_trace_printk: 691 return bpf_get_trace_printk_proto(); 692 case BPF_FUNC_get_smp_processor_id: 693 return &bpf_get_smp_processor_id_proto; 694 case BPF_FUNC_get_numa_node_id: 695 return &bpf_get_numa_node_id_proto; 696 case BPF_FUNC_perf_event_read: 697 return &bpf_perf_event_read_proto; 698 case BPF_FUNC_probe_write_user: 699 return bpf_get_probe_write_proto(); 700 case BPF_FUNC_current_task_under_cgroup: 701 return &bpf_current_task_under_cgroup_proto; 702 case BPF_FUNC_get_prandom_u32: 703 return &bpf_get_prandom_u32_proto; 704 case BPF_FUNC_probe_read_str: 705 return &bpf_probe_read_str_proto; 706 #ifdef CONFIG_CGROUPS 707 case BPF_FUNC_get_current_cgroup_id: 708 return &bpf_get_current_cgroup_id_proto; 709 #endif 710 case BPF_FUNC_send_signal: 711 return &bpf_send_signal_proto; 712 default: 713 return NULL; 714 } 715 } 716 717 static const struct bpf_func_proto * 718 kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 719 { 720 switch (func_id) { 721 case BPF_FUNC_perf_event_output: 722 return &bpf_perf_event_output_proto; 723 case BPF_FUNC_get_stackid: 724 return &bpf_get_stackid_proto; 725 case BPF_FUNC_get_stack: 726 return &bpf_get_stack_proto; 727 case BPF_FUNC_perf_event_read_value: 728 return &bpf_perf_event_read_value_proto; 729 #ifdef CONFIG_BPF_KPROBE_OVERRIDE 730 case BPF_FUNC_override_return: 731 return &bpf_override_return_proto; 732 #endif 733 default: 734 return tracing_func_proto(func_id, prog); 735 } 736 } 737 738 /* bpf+kprobe programs can access fields of 'struct pt_regs' */ 739 static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type, 740 const struct bpf_prog *prog, 741 struct bpf_insn_access_aux *info) 742 { 743 if (off < 0 || off >= sizeof(struct pt_regs)) 744 return false; 745 if (type != BPF_READ) 746 return false; 747 if (off % size != 0) 748 return false; 749 /* 750 * Assertion for 32 bit to make sure last 8 byte access 751 * (BPF_DW) to the last 4 byte member is disallowed. 752 */ 753 if (off + size > sizeof(struct pt_regs)) 754 return false; 755 756 return true; 757 } 758 759 const struct bpf_verifier_ops kprobe_verifier_ops = { 760 .get_func_proto = kprobe_prog_func_proto, 761 .is_valid_access = kprobe_prog_is_valid_access, 762 }; 763 764 const struct bpf_prog_ops kprobe_prog_ops = { 765 }; 766 767 BPF_CALL_5(bpf_perf_event_output_tp, void *, tp_buff, struct bpf_map *, map, 768 u64, flags, void *, data, u64, size) 769 { 770 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 771 772 /* 773 * r1 points to perf tracepoint buffer where first 8 bytes are hidden 774 * from bpf program and contain a pointer to 'struct pt_regs'. Fetch it 775 * from there and call the same bpf_perf_event_output() helper inline. 776 */ 777 return ____bpf_perf_event_output(regs, map, flags, data, size); 778 } 779 780 static const struct bpf_func_proto bpf_perf_event_output_proto_tp = { 781 .func = bpf_perf_event_output_tp, 782 .gpl_only = true, 783 .ret_type = RET_INTEGER, 784 .arg1_type = ARG_PTR_TO_CTX, 785 .arg2_type = ARG_CONST_MAP_PTR, 786 .arg3_type = ARG_ANYTHING, 787 .arg4_type = ARG_PTR_TO_MEM, 788 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 789 }; 790 791 BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map, 792 u64, flags) 793 { 794 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 795 796 /* 797 * Same comment as in bpf_perf_event_output_tp(), only that this time 798 * the other helper's function body cannot be inlined due to being 799 * external, thus we need to call raw helper function. 800 */ 801 return bpf_get_stackid((unsigned long) regs, (unsigned long) map, 802 flags, 0, 0); 803 } 804 805 static const struct bpf_func_proto bpf_get_stackid_proto_tp = { 806 .func = bpf_get_stackid_tp, 807 .gpl_only = true, 808 .ret_type = RET_INTEGER, 809 .arg1_type = ARG_PTR_TO_CTX, 810 .arg2_type = ARG_CONST_MAP_PTR, 811 .arg3_type = ARG_ANYTHING, 812 }; 813 814 BPF_CALL_4(bpf_get_stack_tp, void *, tp_buff, void *, buf, u32, size, 815 u64, flags) 816 { 817 struct pt_regs *regs = *(struct pt_regs **)tp_buff; 818 819 return bpf_get_stack((unsigned long) regs, (unsigned long) buf, 820 (unsigned long) size, flags, 0); 821 } 822 823 static const struct bpf_func_proto bpf_get_stack_proto_tp = { 824 .func = bpf_get_stack_tp, 825 .gpl_only = true, 826 .ret_type = RET_INTEGER, 827 .arg1_type = ARG_PTR_TO_CTX, 828 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 829 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 830 .arg4_type = ARG_ANYTHING, 831 }; 832 833 static const struct bpf_func_proto * 834 tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 835 { 836 switch (func_id) { 837 case BPF_FUNC_perf_event_output: 838 return &bpf_perf_event_output_proto_tp; 839 case BPF_FUNC_get_stackid: 840 return &bpf_get_stackid_proto_tp; 841 case BPF_FUNC_get_stack: 842 return &bpf_get_stack_proto_tp; 843 default: 844 return tracing_func_proto(func_id, prog); 845 } 846 } 847 848 static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type, 849 const struct bpf_prog *prog, 850 struct bpf_insn_access_aux *info) 851 { 852 if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE) 853 return false; 854 if (type != BPF_READ) 855 return false; 856 if (off % size != 0) 857 return false; 858 859 BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(__u64)); 860 return true; 861 } 862 863 const struct bpf_verifier_ops tracepoint_verifier_ops = { 864 .get_func_proto = tp_prog_func_proto, 865 .is_valid_access = tp_prog_is_valid_access, 866 }; 867 868 const struct bpf_prog_ops tracepoint_prog_ops = { 869 }; 870 871 BPF_CALL_3(bpf_perf_prog_read_value, struct bpf_perf_event_data_kern *, ctx, 872 struct bpf_perf_event_value *, buf, u32, size) 873 { 874 int err = -EINVAL; 875 876 if (unlikely(size != sizeof(struct bpf_perf_event_value))) 877 goto clear; 878 err = perf_event_read_local(ctx->event, &buf->counter, &buf->enabled, 879 &buf->running); 880 if (unlikely(err)) 881 goto clear; 882 return 0; 883 clear: 884 memset(buf, 0, size); 885 return err; 886 } 887 888 static const struct bpf_func_proto bpf_perf_prog_read_value_proto = { 889 .func = bpf_perf_prog_read_value, 890 .gpl_only = true, 891 .ret_type = RET_INTEGER, 892 .arg1_type = ARG_PTR_TO_CTX, 893 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 894 .arg3_type = ARG_CONST_SIZE, 895 }; 896 897 static const struct bpf_func_proto * 898 pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 899 { 900 switch (func_id) { 901 case BPF_FUNC_perf_event_output: 902 return &bpf_perf_event_output_proto_tp; 903 case BPF_FUNC_get_stackid: 904 return &bpf_get_stackid_proto_tp; 905 case BPF_FUNC_get_stack: 906 return &bpf_get_stack_proto_tp; 907 case BPF_FUNC_perf_prog_read_value: 908 return &bpf_perf_prog_read_value_proto; 909 default: 910 return tracing_func_proto(func_id, prog); 911 } 912 } 913 914 /* 915 * bpf_raw_tp_regs are separate from bpf_pt_regs used from skb/xdp 916 * to avoid potential recursive reuse issue when/if tracepoints are added 917 * inside bpf_*_event_output, bpf_get_stackid and/or bpf_get_stack. 918 * 919 * Since raw tracepoints run despite bpf_prog_active, support concurrent usage 920 * in normal, irq, and nmi context. 921 */ 922 struct bpf_raw_tp_regs { 923 struct pt_regs regs[3]; 924 }; 925 static DEFINE_PER_CPU(struct bpf_raw_tp_regs, bpf_raw_tp_regs); 926 static DEFINE_PER_CPU(int, bpf_raw_tp_nest_level); 927 static struct pt_regs *get_bpf_raw_tp_regs(void) 928 { 929 struct bpf_raw_tp_regs *tp_regs = this_cpu_ptr(&bpf_raw_tp_regs); 930 int nest_level = this_cpu_inc_return(bpf_raw_tp_nest_level); 931 932 if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(tp_regs->regs))) { 933 this_cpu_dec(bpf_raw_tp_nest_level); 934 return ERR_PTR(-EBUSY); 935 } 936 937 return &tp_regs->regs[nest_level - 1]; 938 } 939 940 static void put_bpf_raw_tp_regs(void) 941 { 942 this_cpu_dec(bpf_raw_tp_nest_level); 943 } 944 945 BPF_CALL_5(bpf_perf_event_output_raw_tp, struct bpf_raw_tracepoint_args *, args, 946 struct bpf_map *, map, u64, flags, void *, data, u64, size) 947 { 948 struct pt_regs *regs = get_bpf_raw_tp_regs(); 949 int ret; 950 951 if (IS_ERR(regs)) 952 return PTR_ERR(regs); 953 954 perf_fetch_caller_regs(regs); 955 ret = ____bpf_perf_event_output(regs, map, flags, data, size); 956 957 put_bpf_raw_tp_regs(); 958 return ret; 959 } 960 961 static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = { 962 .func = bpf_perf_event_output_raw_tp, 963 .gpl_only = true, 964 .ret_type = RET_INTEGER, 965 .arg1_type = ARG_PTR_TO_CTX, 966 .arg2_type = ARG_CONST_MAP_PTR, 967 .arg3_type = ARG_ANYTHING, 968 .arg4_type = ARG_PTR_TO_MEM, 969 .arg5_type = ARG_CONST_SIZE_OR_ZERO, 970 }; 971 972 BPF_CALL_3(bpf_get_stackid_raw_tp, struct bpf_raw_tracepoint_args *, args, 973 struct bpf_map *, map, u64, flags) 974 { 975 struct pt_regs *regs = get_bpf_raw_tp_regs(); 976 int ret; 977 978 if (IS_ERR(regs)) 979 return PTR_ERR(regs); 980 981 perf_fetch_caller_regs(regs); 982 /* similar to bpf_perf_event_output_tp, but pt_regs fetched differently */ 983 ret = bpf_get_stackid((unsigned long) regs, (unsigned long) map, 984 flags, 0, 0); 985 put_bpf_raw_tp_regs(); 986 return ret; 987 } 988 989 static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = { 990 .func = bpf_get_stackid_raw_tp, 991 .gpl_only = true, 992 .ret_type = RET_INTEGER, 993 .arg1_type = ARG_PTR_TO_CTX, 994 .arg2_type = ARG_CONST_MAP_PTR, 995 .arg3_type = ARG_ANYTHING, 996 }; 997 998 BPF_CALL_4(bpf_get_stack_raw_tp, struct bpf_raw_tracepoint_args *, args, 999 void *, buf, u32, size, u64, flags) 1000 { 1001 struct pt_regs *regs = get_bpf_raw_tp_regs(); 1002 int ret; 1003 1004 if (IS_ERR(regs)) 1005 return PTR_ERR(regs); 1006 1007 perf_fetch_caller_regs(regs); 1008 ret = bpf_get_stack((unsigned long) regs, (unsigned long) buf, 1009 (unsigned long) size, flags, 0); 1010 put_bpf_raw_tp_regs(); 1011 return ret; 1012 } 1013 1014 static const struct bpf_func_proto bpf_get_stack_proto_raw_tp = { 1015 .func = bpf_get_stack_raw_tp, 1016 .gpl_only = true, 1017 .ret_type = RET_INTEGER, 1018 .arg1_type = ARG_PTR_TO_CTX, 1019 .arg2_type = ARG_PTR_TO_MEM, 1020 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 1021 .arg4_type = ARG_ANYTHING, 1022 }; 1023 1024 static const struct bpf_func_proto * 1025 raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1026 { 1027 switch (func_id) { 1028 case BPF_FUNC_perf_event_output: 1029 return &bpf_perf_event_output_proto_raw_tp; 1030 case BPF_FUNC_get_stackid: 1031 return &bpf_get_stackid_proto_raw_tp; 1032 case BPF_FUNC_get_stack: 1033 return &bpf_get_stack_proto_raw_tp; 1034 default: 1035 return tracing_func_proto(func_id, prog); 1036 } 1037 } 1038 1039 static bool raw_tp_prog_is_valid_access(int off, int size, 1040 enum bpf_access_type type, 1041 const struct bpf_prog *prog, 1042 struct bpf_insn_access_aux *info) 1043 { 1044 /* largest tracepoint in the kernel has 12 args */ 1045 if (off < 0 || off >= sizeof(__u64) * 12) 1046 return false; 1047 if (type != BPF_READ) 1048 return false; 1049 if (off % size != 0) 1050 return false; 1051 return true; 1052 } 1053 1054 const struct bpf_verifier_ops raw_tracepoint_verifier_ops = { 1055 .get_func_proto = raw_tp_prog_func_proto, 1056 .is_valid_access = raw_tp_prog_is_valid_access, 1057 }; 1058 1059 const struct bpf_prog_ops raw_tracepoint_prog_ops = { 1060 }; 1061 1062 static bool raw_tp_writable_prog_is_valid_access(int off, int size, 1063 enum bpf_access_type type, 1064 const struct bpf_prog *prog, 1065 struct bpf_insn_access_aux *info) 1066 { 1067 if (off == 0) { 1068 if (size != sizeof(u64) || type != BPF_READ) 1069 return false; 1070 info->reg_type = PTR_TO_TP_BUFFER; 1071 } 1072 return raw_tp_prog_is_valid_access(off, size, type, prog, info); 1073 } 1074 1075 const struct bpf_verifier_ops raw_tracepoint_writable_verifier_ops = { 1076 .get_func_proto = raw_tp_prog_func_proto, 1077 .is_valid_access = raw_tp_writable_prog_is_valid_access, 1078 }; 1079 1080 const struct bpf_prog_ops raw_tracepoint_writable_prog_ops = { 1081 }; 1082 1083 static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type, 1084 const struct bpf_prog *prog, 1085 struct bpf_insn_access_aux *info) 1086 { 1087 const int size_u64 = sizeof(u64); 1088 1089 if (off < 0 || off >= sizeof(struct bpf_perf_event_data)) 1090 return false; 1091 if (type != BPF_READ) 1092 return false; 1093 if (off % size != 0) { 1094 if (sizeof(unsigned long) != 4) 1095 return false; 1096 if (size != 8) 1097 return false; 1098 if (off % size != 4) 1099 return false; 1100 } 1101 1102 switch (off) { 1103 case bpf_ctx_range(struct bpf_perf_event_data, sample_period): 1104 bpf_ctx_record_field_size(info, size_u64); 1105 if (!bpf_ctx_narrow_access_ok(off, size, size_u64)) 1106 return false; 1107 break; 1108 case bpf_ctx_range(struct bpf_perf_event_data, addr): 1109 bpf_ctx_record_field_size(info, size_u64); 1110 if (!bpf_ctx_narrow_access_ok(off, size, size_u64)) 1111 return false; 1112 break; 1113 default: 1114 if (size != sizeof(long)) 1115 return false; 1116 } 1117 1118 return true; 1119 } 1120 1121 static u32 pe_prog_convert_ctx_access(enum bpf_access_type type, 1122 const struct bpf_insn *si, 1123 struct bpf_insn *insn_buf, 1124 struct bpf_prog *prog, u32 *target_size) 1125 { 1126 struct bpf_insn *insn = insn_buf; 1127 1128 switch (si->off) { 1129 case offsetof(struct bpf_perf_event_data, sample_period): 1130 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 1131 data), si->dst_reg, si->src_reg, 1132 offsetof(struct bpf_perf_event_data_kern, data)); 1133 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg, 1134 bpf_target_off(struct perf_sample_data, period, 8, 1135 target_size)); 1136 break; 1137 case offsetof(struct bpf_perf_event_data, addr): 1138 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 1139 data), si->dst_reg, si->src_reg, 1140 offsetof(struct bpf_perf_event_data_kern, data)); 1141 *insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg, 1142 bpf_target_off(struct perf_sample_data, addr, 8, 1143 target_size)); 1144 break; 1145 default: 1146 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern, 1147 regs), si->dst_reg, si->src_reg, 1148 offsetof(struct bpf_perf_event_data_kern, regs)); 1149 *insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), si->dst_reg, si->dst_reg, 1150 si->off); 1151 break; 1152 } 1153 1154 return insn - insn_buf; 1155 } 1156 1157 const struct bpf_verifier_ops perf_event_verifier_ops = { 1158 .get_func_proto = pe_prog_func_proto, 1159 .is_valid_access = pe_prog_is_valid_access, 1160 .convert_ctx_access = pe_prog_convert_ctx_access, 1161 }; 1162 1163 const struct bpf_prog_ops perf_event_prog_ops = { 1164 }; 1165 1166 static DEFINE_MUTEX(bpf_event_mutex); 1167 1168 #define BPF_TRACE_MAX_PROGS 64 1169 1170 int perf_event_attach_bpf_prog(struct perf_event *event, 1171 struct bpf_prog *prog) 1172 { 1173 struct bpf_prog_array *old_array; 1174 struct bpf_prog_array *new_array; 1175 int ret = -EEXIST; 1176 1177 /* 1178 * Kprobe override only works if they are on the function entry, 1179 * and only if they are on the opt-in list. 1180 */ 1181 if (prog->kprobe_override && 1182 (!trace_kprobe_on_func_entry(event->tp_event) || 1183 !trace_kprobe_error_injectable(event->tp_event))) 1184 return -EINVAL; 1185 1186 mutex_lock(&bpf_event_mutex); 1187 1188 if (event->prog) 1189 goto unlock; 1190 1191 old_array = bpf_event_rcu_dereference(event->tp_event->prog_array); 1192 if (old_array && 1193 bpf_prog_array_length(old_array) >= BPF_TRACE_MAX_PROGS) { 1194 ret = -E2BIG; 1195 goto unlock; 1196 } 1197 1198 ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array); 1199 if (ret < 0) 1200 goto unlock; 1201 1202 /* set the new array to event->tp_event and set event->prog */ 1203 event->prog = prog; 1204 rcu_assign_pointer(event->tp_event->prog_array, new_array); 1205 bpf_prog_array_free(old_array); 1206 1207 unlock: 1208 mutex_unlock(&bpf_event_mutex); 1209 return ret; 1210 } 1211 1212 void perf_event_detach_bpf_prog(struct perf_event *event) 1213 { 1214 struct bpf_prog_array *old_array; 1215 struct bpf_prog_array *new_array; 1216 int ret; 1217 1218 mutex_lock(&bpf_event_mutex); 1219 1220 if (!event->prog) 1221 goto unlock; 1222 1223 old_array = bpf_event_rcu_dereference(event->tp_event->prog_array); 1224 ret = bpf_prog_array_copy(old_array, event->prog, NULL, &new_array); 1225 if (ret == -ENOENT) 1226 goto unlock; 1227 if (ret < 0) { 1228 bpf_prog_array_delete_safe(old_array, event->prog); 1229 } else { 1230 rcu_assign_pointer(event->tp_event->prog_array, new_array); 1231 bpf_prog_array_free(old_array); 1232 } 1233 1234 bpf_prog_put(event->prog); 1235 event->prog = NULL; 1236 1237 unlock: 1238 mutex_unlock(&bpf_event_mutex); 1239 } 1240 1241 int perf_event_query_prog_array(struct perf_event *event, void __user *info) 1242 { 1243 struct perf_event_query_bpf __user *uquery = info; 1244 struct perf_event_query_bpf query = {}; 1245 struct bpf_prog_array *progs; 1246 u32 *ids, prog_cnt, ids_len; 1247 int ret; 1248 1249 if (!capable(CAP_SYS_ADMIN)) 1250 return -EPERM; 1251 if (event->attr.type != PERF_TYPE_TRACEPOINT) 1252 return -EINVAL; 1253 if (copy_from_user(&query, uquery, sizeof(query))) 1254 return -EFAULT; 1255 1256 ids_len = query.ids_len; 1257 if (ids_len > BPF_TRACE_MAX_PROGS) 1258 return -E2BIG; 1259 ids = kcalloc(ids_len, sizeof(u32), GFP_USER | __GFP_NOWARN); 1260 if (!ids) 1261 return -ENOMEM; 1262 /* 1263 * The above kcalloc returns ZERO_SIZE_PTR when ids_len = 0, which 1264 * is required when user only wants to check for uquery->prog_cnt. 1265 * There is no need to check for it since the case is handled 1266 * gracefully in bpf_prog_array_copy_info. 1267 */ 1268 1269 mutex_lock(&bpf_event_mutex); 1270 progs = bpf_event_rcu_dereference(event->tp_event->prog_array); 1271 ret = bpf_prog_array_copy_info(progs, ids, ids_len, &prog_cnt); 1272 mutex_unlock(&bpf_event_mutex); 1273 1274 if (copy_to_user(&uquery->prog_cnt, &prog_cnt, sizeof(prog_cnt)) || 1275 copy_to_user(uquery->ids, ids, ids_len * sizeof(u32))) 1276 ret = -EFAULT; 1277 1278 kfree(ids); 1279 return ret; 1280 } 1281 1282 extern struct bpf_raw_event_map __start__bpf_raw_tp[]; 1283 extern struct bpf_raw_event_map __stop__bpf_raw_tp[]; 1284 1285 struct bpf_raw_event_map *bpf_get_raw_tracepoint(const char *name) 1286 { 1287 struct bpf_raw_event_map *btp = __start__bpf_raw_tp; 1288 1289 for (; btp < __stop__bpf_raw_tp; btp++) { 1290 if (!strcmp(btp->tp->name, name)) 1291 return btp; 1292 } 1293 1294 return bpf_get_raw_tracepoint_module(name); 1295 } 1296 1297 void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp) 1298 { 1299 struct module *mod = __module_address((unsigned long)btp); 1300 1301 if (mod) 1302 module_put(mod); 1303 } 1304 1305 static __always_inline 1306 void __bpf_trace_run(struct bpf_prog *prog, u64 *args) 1307 { 1308 rcu_read_lock(); 1309 preempt_disable(); 1310 (void) BPF_PROG_RUN(prog, args); 1311 preempt_enable(); 1312 rcu_read_unlock(); 1313 } 1314 1315 #define UNPACK(...) __VA_ARGS__ 1316 #define REPEAT_1(FN, DL, X, ...) FN(X) 1317 #define REPEAT_2(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_1(FN, DL, __VA_ARGS__) 1318 #define REPEAT_3(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_2(FN, DL, __VA_ARGS__) 1319 #define REPEAT_4(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_3(FN, DL, __VA_ARGS__) 1320 #define REPEAT_5(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_4(FN, DL, __VA_ARGS__) 1321 #define REPEAT_6(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_5(FN, DL, __VA_ARGS__) 1322 #define REPEAT_7(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_6(FN, DL, __VA_ARGS__) 1323 #define REPEAT_8(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_7(FN, DL, __VA_ARGS__) 1324 #define REPEAT_9(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_8(FN, DL, __VA_ARGS__) 1325 #define REPEAT_10(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_9(FN, DL, __VA_ARGS__) 1326 #define REPEAT_11(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_10(FN, DL, __VA_ARGS__) 1327 #define REPEAT_12(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_11(FN, DL, __VA_ARGS__) 1328 #define REPEAT(X, FN, DL, ...) REPEAT_##X(FN, DL, __VA_ARGS__) 1329 1330 #define SARG(X) u64 arg##X 1331 #define COPY(X) args[X] = arg##X 1332 1333 #define __DL_COM (,) 1334 #define __DL_SEM (;) 1335 1336 #define __SEQ_0_11 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 1337 1338 #define BPF_TRACE_DEFN_x(x) \ 1339 void bpf_trace_run##x(struct bpf_prog *prog, \ 1340 REPEAT(x, SARG, __DL_COM, __SEQ_0_11)) \ 1341 { \ 1342 u64 args[x]; \ 1343 REPEAT(x, COPY, __DL_SEM, __SEQ_0_11); \ 1344 __bpf_trace_run(prog, args); \ 1345 } \ 1346 EXPORT_SYMBOL_GPL(bpf_trace_run##x) 1347 BPF_TRACE_DEFN_x(1); 1348 BPF_TRACE_DEFN_x(2); 1349 BPF_TRACE_DEFN_x(3); 1350 BPF_TRACE_DEFN_x(4); 1351 BPF_TRACE_DEFN_x(5); 1352 BPF_TRACE_DEFN_x(6); 1353 BPF_TRACE_DEFN_x(7); 1354 BPF_TRACE_DEFN_x(8); 1355 BPF_TRACE_DEFN_x(9); 1356 BPF_TRACE_DEFN_x(10); 1357 BPF_TRACE_DEFN_x(11); 1358 BPF_TRACE_DEFN_x(12); 1359 1360 static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 1361 { 1362 struct tracepoint *tp = btp->tp; 1363 1364 /* 1365 * check that program doesn't access arguments beyond what's 1366 * available in this tracepoint 1367 */ 1368 if (prog->aux->max_ctx_offset > btp->num_args * sizeof(u64)) 1369 return -EINVAL; 1370 1371 if (prog->aux->max_tp_access > btp->writable_size) 1372 return -EINVAL; 1373 1374 return tracepoint_probe_register(tp, (void *)btp->bpf_func, prog); 1375 } 1376 1377 int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 1378 { 1379 return __bpf_probe_register(btp, prog); 1380 } 1381 1382 int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_prog *prog) 1383 { 1384 return tracepoint_probe_unregister(btp->tp, (void *)btp->bpf_func, prog); 1385 } 1386 1387 int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id, 1388 u32 *fd_type, const char **buf, 1389 u64 *probe_offset, u64 *probe_addr) 1390 { 1391 bool is_tracepoint, is_syscall_tp; 1392 struct bpf_prog *prog; 1393 int flags, err = 0; 1394 1395 prog = event->prog; 1396 if (!prog) 1397 return -ENOENT; 1398 1399 /* not supporting BPF_PROG_TYPE_PERF_EVENT yet */ 1400 if (prog->type == BPF_PROG_TYPE_PERF_EVENT) 1401 return -EOPNOTSUPP; 1402 1403 *prog_id = prog->aux->id; 1404 flags = event->tp_event->flags; 1405 is_tracepoint = flags & TRACE_EVENT_FL_TRACEPOINT; 1406 is_syscall_tp = is_syscall_trace_event(event->tp_event); 1407 1408 if (is_tracepoint || is_syscall_tp) { 1409 *buf = is_tracepoint ? event->tp_event->tp->name 1410 : event->tp_event->name; 1411 *fd_type = BPF_FD_TYPE_TRACEPOINT; 1412 *probe_offset = 0x0; 1413 *probe_addr = 0x0; 1414 } else { 1415 /* kprobe/uprobe */ 1416 err = -EOPNOTSUPP; 1417 #ifdef CONFIG_KPROBE_EVENTS 1418 if (flags & TRACE_EVENT_FL_KPROBE) 1419 err = bpf_get_kprobe_info(event, fd_type, buf, 1420 probe_offset, probe_addr, 1421 event->attr.type == PERF_TYPE_TRACEPOINT); 1422 #endif 1423 #ifdef CONFIG_UPROBE_EVENTS 1424 if (flags & TRACE_EVENT_FL_UPROBE) 1425 err = bpf_get_uprobe_info(event, fd_type, buf, 1426 probe_offset, 1427 event->attr.type == PERF_TYPE_TRACEPOINT); 1428 #endif 1429 } 1430 1431 return err; 1432 } 1433 1434 static int __init send_signal_irq_work_init(void) 1435 { 1436 int cpu; 1437 struct send_signal_irq_work *work; 1438 1439 for_each_possible_cpu(cpu) { 1440 work = per_cpu_ptr(&send_signal_work, cpu); 1441 init_irq_work(&work->irq_work, do_bpf_send_signal); 1442 } 1443 return 0; 1444 } 1445 1446 subsys_initcall(send_signal_irq_work_init); 1447 1448 #ifdef CONFIG_MODULES 1449 static int bpf_event_notify(struct notifier_block *nb, unsigned long op, 1450 void *module) 1451 { 1452 struct bpf_trace_module *btm, *tmp; 1453 struct module *mod = module; 1454 1455 if (mod->num_bpf_raw_events == 0 || 1456 (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING)) 1457 return 0; 1458 1459 mutex_lock(&bpf_module_mutex); 1460 1461 switch (op) { 1462 case MODULE_STATE_COMING: 1463 btm = kzalloc(sizeof(*btm), GFP_KERNEL); 1464 if (btm) { 1465 btm->module = module; 1466 list_add(&btm->list, &bpf_trace_modules); 1467 } 1468 break; 1469 case MODULE_STATE_GOING: 1470 list_for_each_entry_safe(btm, tmp, &bpf_trace_modules, list) { 1471 if (btm->module == module) { 1472 list_del(&btm->list); 1473 kfree(btm); 1474 break; 1475 } 1476 } 1477 break; 1478 } 1479 1480 mutex_unlock(&bpf_module_mutex); 1481 1482 return 0; 1483 } 1484 1485 static struct notifier_block bpf_module_nb = { 1486 .notifier_call = bpf_event_notify, 1487 }; 1488 1489 static int __init bpf_event_init(void) 1490 { 1491 register_module_notifier(&bpf_module_nb); 1492 return 0; 1493 } 1494 1495 fs_initcall(bpf_event_init); 1496 #endif /* CONFIG_MODULES */ 1497