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