1// SPDX-License-Identifier: GPL-2.0
2/*
3 * uprobes-based tracing events
4 *
5 * Copyright (C) IBM Corporation, 2010-2012
6 * Author: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
7 */
8#define pr_fmt(fmt) "trace_uprobe: " fmt
9
10#include <linux/ctype.h>
11#include <linux/module.h>
12#include <linux/uaccess.h>
13#include <linux/uprobes.h>
14#include <linux/namei.h>
15#include <linux/string.h>
16#include <linux/rculist.h>
17
18#include "trace_dynevent.h"
19#include "trace_probe.h"
20#include "trace_probe_tmpl.h"
21
22#define UPROBE_EVENT_SYSTEM "uprobes"
23
24struct uprobe_trace_entry_head {
25 struct trace_entry ent;
26 unsigned long vaddr[];
27};
28
29#define SIZEOF_TRACE_ENTRY(is_return) \
30 (sizeof(struct uprobe_trace_entry_head) + \
31 sizeof(unsigned long) * (is_return ? 2 : 1))
32
33#define DATAOF_TRACE_ENTRY(entry, is_return) \
34 ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))
35
36struct trace_uprobe_filter {
37 rwlock_t rwlock;
38 int nr_systemwide;
39 struct list_head perf_events;
40};
41
42static int trace_uprobe_create(int argc, const char **argv);
43static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev);
44static int trace_uprobe_release(struct dyn_event *ev);
45static bool trace_uprobe_is_busy(struct dyn_event *ev);
46static bool trace_uprobe_match(const char *system, const char *event,
47 struct dyn_event *ev);
48
49static struct dyn_event_operations trace_uprobe_ops = {
50 .create = trace_uprobe_create,
51 .show = trace_uprobe_show,
52 .is_busy = trace_uprobe_is_busy,
53 .free = trace_uprobe_release,
54 .match = trace_uprobe_match,
55};
56
57/*
58 * uprobe event core functions
59 */
60struct trace_uprobe {
61 struct dyn_event devent;
62 struct trace_uprobe_filter filter;
63 struct uprobe_consumer consumer;
64 struct path path;
65 struct inode *inode;
66 char *filename;
67 unsigned long offset;
68 unsigned long ref_ctr_offset;
69 unsigned long nhit;
70 struct trace_probe tp;
71};
72
73static bool is_trace_uprobe(struct dyn_event *ev)
74{
75 return ev->ops == &trace_uprobe_ops;
76}
77
78static struct trace_uprobe *to_trace_uprobe(struct dyn_event *ev)
79{
80 return container_of(ev, struct trace_uprobe, devent);
81}
82
83/**
84 * for_each_trace_uprobe - iterate over the trace_uprobe list
85 * @pos: the struct trace_uprobe * for each entry
86 * @dpos: the struct dyn_event * to use as a loop cursor
87 */
88#define for_each_trace_uprobe(pos, dpos) \
89 for_each_dyn_event(dpos) \
90 if (is_trace_uprobe(dpos) && (pos = to_trace_uprobe(dpos)))
91
92#define SIZEOF_TRACE_UPROBE(n) \
93 (offsetof(struct trace_uprobe, tp.args) + \
94 (sizeof(struct probe_arg) * (n)))
95
96static int register_uprobe_event(struct trace_uprobe *tu);
97static int unregister_uprobe_event(struct trace_uprobe *tu);
98
99struct uprobe_dispatch_data {
100 struct trace_uprobe *tu;
101 unsigned long bp_addr;
102};
103
104static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
105static int uretprobe_dispatcher(struct uprobe_consumer *con,
106 unsigned long func, struct pt_regs *regs);
107
108#ifdef CONFIG_STACK_GROWSUP
109static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
110{
111 return addr - (n * sizeof(long));
112}
113#else
114static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
115{
116 return addr + (n * sizeof(long));
117}
118#endif
119
120static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
121{
122 unsigned long ret;
123 unsigned long addr = user_stack_pointer(regs);
124
125 addr = adjust_stack_addr(addr, n);
126
127 if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret)))
128 return 0;
129
130 return ret;
131}
132
133/*
134 * Uprobes-specific fetch functions
135 */
136static nokprobe_inline int
137probe_mem_read(void *dest, void *src, size_t size)
138{
139 void __user *vaddr = (void __force __user *)src;
140
141 return copy_from_user(dest, vaddr, size) ? -EFAULT : 0;
142}
143/*
144 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
145 * length and relative data location.
146 */
147static nokprobe_inline int
148fetch_store_string(unsigned long addr, void *dest, void *base)
149{
150 long ret;
151 u32 loc = *(u32 *)dest;
152 int maxlen = get_loc_len(loc);
153 u8 *dst = get_loc_data(dest, base);
154 void __user *src = (void __force __user *) addr;
155
156 if (unlikely(!maxlen))
157 return -ENOMEM;
158
159 ret = strncpy_from_user(dst, src, maxlen);
160 if (ret >= 0) {
161 if (ret == maxlen)
162 dst[ret - 1] = '\0';
163 else
164 /*
165 * Include the terminating null byte. In this case it
166 * was copied by strncpy_from_user but not accounted
167 * for in ret.
168 */
169 ret++;
170 *(u32 *)dest = make_data_loc(ret, (void *)dst - base);
171 }
172
173 return ret;
174}
175
176/* Return the length of string -- including null terminal byte */
177static nokprobe_inline int
178fetch_store_strlen(unsigned long addr)
179{
180 int len;
181 void __user *vaddr = (void __force __user *) addr;
182
183 len = strnlen_user(vaddr, MAX_STRING_SIZE);
184
185 return (len > MAX_STRING_SIZE) ? 0 : len;
186}
187
188static unsigned long translate_user_vaddr(unsigned long file_offset)
189{
190 unsigned long base_addr;
191 struct uprobe_dispatch_data *udd;
192
193 udd = (void *) current->utask->vaddr;
194
195 base_addr = udd->bp_addr - udd->tu->offset;
196 return base_addr + file_offset;
197}
198
199/* Note that we don't verify it, since the code does not come from user space */
200static int
201process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
202 void *base)
203{
204 unsigned long val;
205
206 /* 1st stage: get value from context */
207 switch (code->op) {
208 case FETCH_OP_REG:
209 val = regs_get_register(regs, code->param);
210 break;
211 case FETCH_OP_STACK:
212 val = get_user_stack_nth(regs, code->param);
213 break;
214 case FETCH_OP_STACKP:
215 val = user_stack_pointer(regs);
216 break;
217 case FETCH_OP_RETVAL:
218 val = regs_return_value(regs);
219 break;
220 case FETCH_OP_IMM:
221 val = code->immediate;
222 break;
223 case FETCH_OP_FOFFS:
224 val = translate_user_vaddr(code->immediate);
225 break;
226 default:
227 return -EILSEQ;
228 }
229 code++;
230
231 return process_fetch_insn_bottom(code, val, dest, base);
232}
233NOKPROBE_SYMBOL(process_fetch_insn)
234
235static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
236{
237 rwlock_init(&filter->rwlock);
238 filter->nr_systemwide = 0;
239 INIT_LIST_HEAD(&filter->perf_events);
240}
241
242static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
243{
244 return !filter->nr_systemwide && list_empty(&filter->perf_events);
245}
246
247static inline bool is_ret_probe(struct trace_uprobe *tu)
248{
249 return tu->consumer.ret_handler != NULL;
250}
251
252static bool trace_uprobe_is_busy(struct dyn_event *ev)
253{
254 struct trace_uprobe *tu = to_trace_uprobe(ev);
255
256 return trace_probe_is_enabled(&tu->tp);
257}
258
259static bool trace_uprobe_match(const char *system, const char *event,
260 struct dyn_event *ev)
261{
262 struct trace_uprobe *tu = to_trace_uprobe(ev);
263
264 return strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
265 (!system || strcmp(tu->tp.call.class->system, system) == 0);
266}
267
268/*
269 * Allocate new trace_uprobe and initialize it (including uprobes).
270 */
271static struct trace_uprobe *
272alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
273{
274 struct trace_uprobe *tu;
275
276 if (!event || !group)
277 return ERR_PTR(-EINVAL);
278
279 tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
280 if (!tu)
281 return ERR_PTR(-ENOMEM);
282
283 tu->tp.call.class = &tu->tp.class;
284 tu->tp.call.name = kstrdup(event, GFP_KERNEL);
285 if (!tu->tp.call.name)
286 goto error;
287
288 tu->tp.class.system = kstrdup(group, GFP_KERNEL);
289 if (!tu->tp.class.system)
290 goto error;
291
292 dyn_event_init(&tu->devent, &trace_uprobe_ops);
293 INIT_LIST_HEAD(&tu->tp.files);
294 tu->consumer.handler = uprobe_dispatcher;
295 if (is_ret)
296 tu->consumer.ret_handler = uretprobe_dispatcher;
297 init_trace_uprobe_filter(&tu->filter);
298 return tu;
299
300error:
301 kfree(tu->tp.call.name);
302 kfree(tu);
303
304 return ERR_PTR(-ENOMEM);
305}
306
307static void free_trace_uprobe(struct trace_uprobe *tu)
308{
309 int i;
310
311 if (!tu)
312 return;
313
314 for (i = 0; i < tu->tp.nr_args; i++)
315 traceprobe_free_probe_arg(&tu->tp.args[i]);
316
317 path_put(&tu->path);
318 kfree(tu->tp.call.class->system);
319 kfree(tu->tp.call.name);
320 kfree(tu->filename);
321 kfree(tu);
322}
323
324static struct trace_uprobe *find_probe_event(const char *event, const char *group)
325{
326 struct dyn_event *pos;
327 struct trace_uprobe *tu;
328
329 for_each_trace_uprobe(tu, pos)
330 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
331 strcmp(tu->tp.call.class->system, group) == 0)
332 return tu;
333
334 return NULL;
335}
336
337/* Unregister a trace_uprobe and probe_event */
338static int unregister_trace_uprobe(struct trace_uprobe *tu)
339{
340 int ret;
341
342 ret = unregister_uprobe_event(tu);
343 if (ret)
344 return ret;
345
346 dyn_event_remove(&tu->devent);
347 free_trace_uprobe(tu);
348 return 0;
349}
350
351/*
352 * Uprobe with multiple reference counter is not allowed. i.e.
353 * If inode and offset matches, reference counter offset *must*
354 * match as well. Though, there is one exception: If user is
355 * replacing old trace_uprobe with new one(same group/event),
356 * then we allow same uprobe with new reference counter as far
357 * as the new one does not conflict with any other existing
358 * ones.
359 */
360static struct trace_uprobe *find_old_trace_uprobe(struct trace_uprobe *new)
361{
362 struct dyn_event *pos;
363 struct trace_uprobe *tmp, *old = NULL;
364 struct inode *new_inode = d_real_inode(new->path.dentry);
365
366 old = find_probe_event(trace_event_name(&new->tp.call),
367 new->tp.call.class->system);
368
369 for_each_trace_uprobe(tmp, pos) {
370 if ((old ? old != tmp : true) &&
371 new_inode == d_real_inode(tmp->path.dentry) &&
372 new->offset == tmp->offset &&
373 new->ref_ctr_offset != tmp->ref_ctr_offset) {
374 pr_warn("Reference counter offset mismatch.");
375 return ERR_PTR(-EINVAL);
376 }
377 }
378 return old;
379}
380
381/* Register a trace_uprobe and probe_event */
382static int register_trace_uprobe(struct trace_uprobe *tu)
383{
384 struct trace_uprobe *old_tu;
385 int ret;
386
387 mutex_lock(&event_mutex);
388
389 /* register as an event */
390 old_tu = find_old_trace_uprobe(tu);
391 if (IS_ERR(old_tu)) {
392 ret = PTR_ERR(old_tu);
393 goto end;
394 }
395
396 if (old_tu) {
397 /* delete old event */
398 ret = unregister_trace_uprobe(old_tu);
399 if (ret)
400 goto end;
401 }
402
403 ret = register_uprobe_event(tu);
404 if (ret) {
405 pr_warn("Failed to register probe event(%d)\n", ret);
406 goto end;
407 }
408
409 dyn_event_add(&tu->devent);
410
411end:
412 mutex_unlock(&event_mutex);
413
414 return ret;
415}
416
417/*
418 * Argument syntax:
419 * - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS]
420 *
421 * - Remove uprobe: -:[GRP/]EVENT
422 */
423static int trace_uprobe_create(int argc, const char **argv)
424{
425 struct trace_uprobe *tu;
426 const char *event = NULL, *group = UPROBE_EVENT_SYSTEM;
427 char *arg, *filename, *rctr, *rctr_end, *tmp;
428 char buf[MAX_EVENT_NAME_LEN];
429 struct path path;
430 unsigned long offset, ref_ctr_offset;
431 bool is_return = false;
432 int i, ret;
433
434 ret = 0;
435 ref_ctr_offset = 0;
436
437 /* argc must be >= 1 */
438 if (argv[0][0] == 'r')
439 is_return = true;
440 else if (argv[0][0] != 'p' || argc < 2)
441 return -ECANCELED;
442
443 if (argv[0][1] == ':')
444 event = &argv[0][2];
445
446 if (!strchr(argv[1], '/'))
447 return -ECANCELED;
448
449 filename = kstrdup(argv[1], GFP_KERNEL);
450 if (!filename)
451 return -ENOMEM;
452
453 /* Find the last occurrence, in case the path contains ':' too. */
454 arg = strrchr(filename, ':');
455 if (!arg || !isdigit(arg[1])) {
456 kfree(filename);
457 return -ECANCELED;
458 }
459
460 *arg++ = '\0';
461 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
462 if (ret) {
463 kfree(filename);
464 return ret;
465 }
466 if (!d_is_reg(path.dentry)) {
467 ret = -EINVAL;
468 goto fail_address_parse;
469 }
470
471 /* Parse reference counter offset if specified. */
472 rctr = strchr(arg, '(');
473 if (rctr) {
474 rctr_end = strchr(rctr, ')');
475 if (rctr > rctr_end || *(rctr_end + 1) != 0) {
476 ret = -EINVAL;
477 pr_info("Invalid reference counter offset.\n");
478 goto fail_address_parse;
479 }
480
481 *rctr++ = '\0';
482 *rctr_end = '\0';
483 ret = kstrtoul(rctr, 0, &ref_ctr_offset);
484 if (ret) {
485 pr_info("Invalid reference counter offset.\n");
486 goto fail_address_parse;
487 }
488 }
489
490 /* Parse uprobe offset. */
491 ret = kstrtoul(arg, 0, &offset);
492 if (ret)
493 goto fail_address_parse;
494
495 argc -= 2;
496 argv += 2;
497
498 /* setup a probe */
499 if (event) {
500 ret = traceprobe_parse_event_name(&event, &group, buf);
501 if (ret)
502 goto fail_address_parse;
503 } else {
504 char *tail;
505 char *ptr;
506
507 tail = kstrdup(kbasename(filename), GFP_KERNEL);
508 if (!tail) {
509 ret = -ENOMEM;
510 goto fail_address_parse;
511 }
512
513 ptr = strpbrk(tail, ".-_");
514 if (ptr)
515 *ptr = '\0';
516
517 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
518 event = buf;
519 kfree(tail);
520 }
521
522 tu = alloc_trace_uprobe(group, event, argc, is_return);
523 if (IS_ERR(tu)) {
524 ret = PTR_ERR(tu);
525 /* This must return -ENOMEM otherwise there is a bug */
526 WARN_ON_ONCE(ret != -ENOMEM);
527 goto fail_address_parse;
528 }
529 tu->offset = offset;
530 tu->ref_ctr_offset = ref_ctr_offset;
531 tu->path = path;
532 tu->filename = filename;
533
534 /* parse arguments */
535 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
536 tmp = kstrdup(argv[i], GFP_KERNEL);
537 if (!tmp) {
538 ret = -ENOMEM;
539 goto error;
540 }
541
542 ret = traceprobe_parse_probe_arg(&tu->tp, i, tmp,
543 is_return ? TPARG_FL_RETURN : 0);
544 kfree(tmp);
545 if (ret)
546 goto error;
547 }
548
549 ret = register_trace_uprobe(tu);
550 if (ret)
551 goto error;
552 return 0;
553
554error:
555 free_trace_uprobe(tu);
556 return ret;
557
558fail_address_parse:
559 path_put(&path);
560 kfree(filename);
561
562 pr_info("Failed to parse address or file.\n");
563
564 return ret;
565}
566
567static int create_or_delete_trace_uprobe(int argc, char **argv)
568{
569 int ret;
570
571 if (argv[0][0] == '-')
572 return dyn_event_release(argc, argv, &trace_uprobe_ops);
573
574 ret = trace_uprobe_create(argc, (const char **)argv);
575 return ret == -ECANCELED ? -EINVAL : ret;
576}
577
578static int trace_uprobe_release(struct dyn_event *ev)
579{
580 struct trace_uprobe *tu = to_trace_uprobe(ev);
581
582 return unregister_trace_uprobe(tu);
583}
584
585/* Probes listing interfaces */
586static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev)
587{
588 struct trace_uprobe *tu = to_trace_uprobe(ev);
589 char c = is_ret_probe(tu) ? 'r' : 'p';
590 int i;
591
592 seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, tu->tp.call.class->system,
593 trace_event_name(&tu->tp.call), tu->filename,
594 (int)(sizeof(void *) * 2), tu->offset);
595
596 if (tu->ref_ctr_offset)
597 seq_printf(m, "(0x%lx)", tu->ref_ctr_offset);
598
599 for (i = 0; i < tu->tp.nr_args; i++)
600 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
601
602 seq_putc(m, '\n');
603 return 0;
604}
605
606static int probes_seq_show(struct seq_file *m, void *v)
607{
608 struct dyn_event *ev = v;
609
610 if (!is_trace_uprobe(ev))
611 return 0;
612
613 return trace_uprobe_show(m, ev);
614}
615
616static const struct seq_operations probes_seq_op = {
617 .start = dyn_event_seq_start,
618 .next = dyn_event_seq_next,
619 .stop = dyn_event_seq_stop,
620 .show = probes_seq_show
621};
622
623static int probes_open(struct inode *inode, struct file *file)
624{
625 int ret;
626
627 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
628 ret = dyn_events_release_all(&trace_uprobe_ops);
629 if (ret)
630 return ret;
631 }
632
633 return seq_open(file, &probes_seq_op);
634}
635
636static ssize_t probes_write(struct file *file, const char __user *buffer,
637 size_t count, loff_t *ppos)
638{
639 return trace_parse_run_command(file, buffer, count, ppos,
640 create_or_delete_trace_uprobe);
641}
642
643static const struct file_operations uprobe_events_ops = {
644 .owner = THIS_MODULE,
645 .open = probes_open,
646 .read = seq_read,
647 .llseek = seq_lseek,
648 .release = seq_release,
649 .write = probes_write,
650};
651
652/* Probes profiling interfaces */
653static int probes_profile_seq_show(struct seq_file *m, void *v)
654{
655 struct dyn_event *ev = v;
656 struct trace_uprobe *tu;
657
658 if (!is_trace_uprobe(ev))
659 return 0;
660
661 tu = to_trace_uprobe(ev);
662 seq_printf(m, " %s %-44s %15lu\n", tu->filename,
663 trace_event_name(&tu->tp.call), tu->nhit);
664 return 0;
665}
666
667static const struct seq_operations profile_seq_op = {
668 .start = dyn_event_seq_start,
669 .next = dyn_event_seq_next,
670 .stop = dyn_event_seq_stop,
671 .show = probes_profile_seq_show
672};
673
674static int profile_open(struct inode *inode, struct file *file)
675{
676 return seq_open(file, &profile_seq_op);
677}
678
679static const struct file_operations uprobe_profile_ops = {
680 .owner = THIS_MODULE,
681 .open = profile_open,
682 .read = seq_read,
683 .llseek = seq_lseek,
684 .release = seq_release,
685};
686
687struct uprobe_cpu_buffer {
688 struct mutex mutex;
689 void *buf;
690};
691static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer;
692static int uprobe_buffer_refcnt;
693
694static int uprobe_buffer_init(void)
695{
696 int cpu, err_cpu;
697
698 uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer);
699 if (uprobe_cpu_buffer == NULL)
700 return -ENOMEM;
701
702 for_each_possible_cpu(cpu) {
703 struct page *p = alloc_pages_node(cpu_to_node(cpu),
704 GFP_KERNEL, 0);
705 if (p == NULL) {
706 err_cpu = cpu;
707 goto err;
708 }
709 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p);
710 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex);
711 }
712
713 return 0;
714
715err:
716 for_each_possible_cpu(cpu) {
717 if (cpu == err_cpu)
718 break;
719 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf);
720 }
721
722 free_percpu(uprobe_cpu_buffer);
723 return -ENOMEM;
724}
725
726static int uprobe_buffer_enable(void)
727{
728 int ret = 0;
729
730 BUG_ON(!mutex_is_locked(&event_mutex));
731
732 if (uprobe_buffer_refcnt++ == 0) {
733 ret = uprobe_buffer_init();
734 if (ret < 0)
735 uprobe_buffer_refcnt--;
736 }
737
738 return ret;
739}
740
741static void uprobe_buffer_disable(void)
742{
743 int cpu;
744
745 BUG_ON(!mutex_is_locked(&event_mutex));
746
747 if (--uprobe_buffer_refcnt == 0) {
748 for_each_possible_cpu(cpu)
749 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
750 cpu)->buf);
751
752 free_percpu(uprobe_cpu_buffer);
753 uprobe_cpu_buffer = NULL;
754 }
755}
756
757static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
758{
759 struct uprobe_cpu_buffer *ucb;
760 int cpu;
761
762 cpu = raw_smp_processor_id();
763 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);
764
765 /*
766 * Use per-cpu buffers for fastest access, but we might migrate
767 * so the mutex makes sure we have sole access to it.
768 */
769 mutex_lock(&ucb->mutex);
770
771 return ucb;
772}
773
774static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
775{
776 mutex_unlock(&ucb->mutex);
777}
778
779static void __uprobe_trace_func(struct trace_uprobe *tu,
780 unsigned long func, struct pt_regs *regs,
781 struct uprobe_cpu_buffer *ucb, int dsize,
782 struct trace_event_file *trace_file)
783{
784 struct uprobe_trace_entry_head *entry;
785 struct ring_buffer_event *event;
786 struct ring_buffer *buffer;
787 void *data;
788 int size, esize;
789 struct trace_event_call *call = &tu->tp.call;
790
791 WARN_ON(call != trace_file->event_call);
792
793 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
794 return;
795
796 if (trace_trigger_soft_disabled(trace_file))
797 return;
798
799 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
800 size = esize + tu->tp.size + dsize;
801 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
802 call->event.type, size, 0, 0);
803 if (!event)
804 return;
805
806 entry = ring_buffer_event_data(event);
807 if (is_ret_probe(tu)) {
808 entry->vaddr[0] = func;
809 entry->vaddr[1] = instruction_pointer(regs);
810 data = DATAOF_TRACE_ENTRY(entry, true);
811 } else {
812 entry->vaddr[0] = instruction_pointer(regs);
813 data = DATAOF_TRACE_ENTRY(entry, false);
814 }
815
816 memcpy(data, ucb->buf, tu->tp.size + dsize);
817
818 event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0);
819}
820
821/* uprobe handler */
822static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
823 struct uprobe_cpu_buffer *ucb, int dsize)
824{
825 struct event_file_link *link;
826
827 if (is_ret_probe(tu))
828 return 0;
829
830 rcu_read_lock();
831 list_for_each_entry_rcu(link, &tu->tp.files, list)
832 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
833 rcu_read_unlock();
834
835 return 0;
836}
837
838static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
839 struct pt_regs *regs,
840 struct uprobe_cpu_buffer *ucb, int dsize)
841{
842 struct event_file_link *link;
843
844 rcu_read_lock();
845 list_for_each_entry_rcu(link, &tu->tp.files, list)
846 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
847 rcu_read_unlock();
848}
849
850/* Event entry printers */
851static enum print_line_t
852print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
853{
854 struct uprobe_trace_entry_head *entry;
855 struct trace_seq *s = &iter->seq;
856 struct trace_uprobe *tu;
857 u8 *data;
858
859 entry = (struct uprobe_trace_entry_head *)iter->ent;
860 tu = container_of(event, struct trace_uprobe, tp.call.event);
861
862 if (is_ret_probe(tu)) {
863 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
864 trace_event_name(&tu->tp.call),
865 entry->vaddr[1], entry->vaddr[0]);
866 data = DATAOF_TRACE_ENTRY(entry, true);
867 } else {
868 trace_seq_printf(s, "%s: (0x%lx)",
869 trace_event_name(&tu->tp.call),
870 entry->vaddr[0]);
871 data = DATAOF_TRACE_ENTRY(entry, false);
872 }
873
874 if (print_probe_args(s, tu->tp.args, tu->tp.nr_args, data, entry) < 0)
875 goto out;
876
877 trace_seq_putc(s, '\n');
878
879 out:
880 return trace_handle_return(s);
881}
882
883typedef bool (*filter_func_t)(struct uprobe_consumer *self,
884 enum uprobe_filter_ctx ctx,
885 struct mm_struct *mm);
886
887static int
888probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file,
889 filter_func_t filter)
890{
891 bool enabled = trace_probe_is_enabled(&tu->tp);
892 struct event_file_link *link = NULL;
893 int ret;
894
895 if (file) {
896 if (tu->tp.flags & TP_FLAG_PROFILE)
897 return -EINTR;
898
899 link = kmalloc(sizeof(*link), GFP_KERNEL);
900 if (!link)
901 return -ENOMEM;
902
903 link->file = file;
904 list_add_tail_rcu(&link->list, &tu->tp.files);
905
906 tu->tp.flags |= TP_FLAG_TRACE;
907 } else {
908 if (tu->tp.flags & TP_FLAG_TRACE)
909 return -EINTR;
910
911 tu->tp.flags |= TP_FLAG_PROFILE;
912 }
913
914 WARN_ON(!uprobe_filter_is_empty(&tu->filter));
915
916 if (enabled)
917 return 0;
918
919 ret = uprobe_buffer_enable();
920 if (ret)
921 goto err_flags;
922
923 tu->consumer.filter = filter;
924 tu->inode = d_real_inode(tu->path.dentry);
925 if (tu->ref_ctr_offset) {
926 ret = uprobe_register_refctr(tu->inode, tu->offset,
927 tu->ref_ctr_offset, &tu->consumer);
928 } else {
929 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
930 }
931
932 if (ret)
933 goto err_buffer;
934
935 return 0;
936
937 err_buffer:
938 uprobe_buffer_disable();
939
940 err_flags:
941 if (file) {
942 list_del(&link->list);
943 kfree(link);
944 tu->tp.flags &= ~TP_FLAG_TRACE;
945 } else {
946 tu->tp.flags &= ~TP_FLAG_PROFILE;
947 }
948 return ret;
949}
950
951static void
952probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file)
953{
954 if (!trace_probe_is_enabled(&tu->tp))
955 return;
956
957 if (file) {
958 struct event_file_link *link;
959
960 link = find_event_file_link(&tu->tp, file);
961 if (!link)
962 return;
963
964 list_del_rcu(&link->list);
965 /* synchronize with u{,ret}probe_trace_func */
966 synchronize_rcu();
967 kfree(link);
968
969 if (!list_empty(&tu->tp.files))
970 return;
971 }
972
973 WARN_ON(!uprobe_filter_is_empty(&tu->filter));
974
975 uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
976 tu->inode = NULL;
977 tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
978
979 uprobe_buffer_disable();
980}
981
982static int uprobe_event_define_fields(struct trace_event_call *event_call)
983{
984 int ret, size;
985 struct uprobe_trace_entry_head field;
986 struct trace_uprobe *tu = event_call->data;
987
988 if (is_ret_probe(tu)) {
989 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
990 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
991 size = SIZEOF_TRACE_ENTRY(true);
992 } else {
993 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
994 size = SIZEOF_TRACE_ENTRY(false);
995 }
996
997 return traceprobe_define_arg_fields(event_call, size, &tu->tp);
998}
999
1000#ifdef CONFIG_PERF_EVENTS
1001static bool
1002__uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
1003{
1004 struct perf_event *event;
1005
1006 if (filter->nr_systemwide)
1007 return true;
1008
1009 list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
1010 if (event->hw.target->mm == mm)
1011 return true;
1012 }
1013
1014 return false;
1015}
1016
1017static inline bool
1018uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
1019{
1020 return __uprobe_perf_filter(&tu->filter, event->hw.target->mm);
1021}
1022
1023static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
1024{
1025 bool done;
1026
1027 write_lock(&tu->filter.rwlock);
1028 if (event->hw.target) {
1029 list_del(&event->hw.tp_list);
1030 done = tu->filter.nr_systemwide ||
1031 (event->hw.target->flags & PF_EXITING) ||
1032 uprobe_filter_event(tu, event);
1033 } else {
1034 tu->filter.nr_systemwide--;
1035 done = tu->filter.nr_systemwide;
1036 }
1037 write_unlock(&tu->filter.rwlock);
1038
1039 if (!done)
1040 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
1041
1042 return 0;
1043}
1044
1045static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
1046{
1047 bool done;
1048 int err;
1049
1050 write_lock(&tu->filter.rwlock);
1051 if (event->hw.target) {
1052 /*
1053 * event->parent != NULL means copy_process(), we can avoid
1054 * uprobe_apply(). current->mm must be probed and we can rely
1055 * on dup_mmap() which preserves the already installed bp's.
1056 *
1057 * attr.enable_on_exec means that exec/mmap will install the
1058 * breakpoints we need.
1059 */
1060 done = tu->filter.nr_systemwide ||
1061 event->parent || event->attr.enable_on_exec ||
1062 uprobe_filter_event(tu, event);
1063 list_add(&event->hw.tp_list, &tu->filter.perf_events);
1064 } else {
1065 done = tu->filter.nr_systemwide;
1066 tu->filter.nr_systemwide++;
1067 }
1068 write_unlock(&tu->filter.rwlock);
1069
1070 err = 0;
1071 if (!done) {
1072 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
1073 if (err)
1074 uprobe_perf_close(tu, event);
1075 }
1076 return err;
1077}
1078
1079static bool uprobe_perf_filter(struct uprobe_consumer *uc,
1080 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
1081{
1082 struct trace_uprobe *tu;
1083 int ret;
1084
1085 tu = container_of(uc, struct trace_uprobe, consumer);
1086 read_lock(&tu->filter.rwlock);
1087 ret = __uprobe_perf_filter(&tu->filter, mm);
1088 read_unlock(&tu->filter.rwlock);
1089
1090 return ret;
1091}
1092
1093static void __uprobe_perf_func(struct trace_uprobe *tu,
1094 unsigned long func, struct pt_regs *regs,
1095 struct uprobe_cpu_buffer *ucb, int dsize)
1096{
1097 struct trace_event_call *call = &tu->tp.call;
1098 struct uprobe_trace_entry_head *entry;
1099 struct hlist_head *head;
1100 void *data;
1101 int size, esize;
1102 int rctx;
1103
1104 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1105 return;
1106
1107 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1108
1109 size = esize + tu->tp.size + dsize;
1110 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
1111 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
1112 return;
1113
1114 preempt_disable();
1115 head = this_cpu_ptr(call->perf_events);
1116 if (hlist_empty(head))
1117 goto out;
1118
1119 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1120 if (!entry)
1121 goto out;
1122
1123 if (is_ret_probe(tu)) {
1124 entry->vaddr[0] = func;
1125 entry->vaddr[1] = instruction_pointer(regs);
1126 data = DATAOF_TRACE_ENTRY(entry, true);
1127 } else {
1128 entry->vaddr[0] = instruction_pointer(regs);
1129 data = DATAOF_TRACE_ENTRY(entry, false);
1130 }
1131
1132 memcpy(data, ucb->buf, tu->tp.size + dsize);
1133
1134 if (size - esize > tu->tp.size + dsize) {
1135 int len = tu->tp.size + dsize;
1136
1137 memset(data + len, 0, size - esize - len);
1138 }
1139
1140 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1141 head, NULL);
1142 out:
1143 preempt_enable();
1144}
1145
1146/* uprobe profile handler */
1147static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
1148 struct uprobe_cpu_buffer *ucb, int dsize)
1149{
1150 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
1151 return UPROBE_HANDLER_REMOVE;
1152
1153 if (!is_ret_probe(tu))
1154 __uprobe_perf_func(tu, 0, regs, ucb, dsize);
1155 return 0;
1156}
1157
1158static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
1159 struct pt_regs *regs,
1160 struct uprobe_cpu_buffer *ucb, int dsize)
1161{
1162 __uprobe_perf_func(tu, func, regs, ucb, dsize);
1163}
1164
1165int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type,
1166 const char **filename, u64 *probe_offset,
1167 bool perf_type_tracepoint)
1168{
1169 const char *pevent = trace_event_name(event->tp_event);
1170 const char *group = event->tp_event->class->system;
1171 struct trace_uprobe *tu;
1172
1173 if (perf_type_tracepoint)
1174 tu = find_probe_event(pevent, group);
1175 else
1176 tu = event->tp_event->data;
1177 if (!tu)
1178 return -EINVAL;
1179
1180 *fd_type = is_ret_probe(tu) ? BPF_FD_TYPE_URETPROBE
1181 : BPF_FD_TYPE_UPROBE;
1182 *filename = tu->filename;
1183 *probe_offset = tu->offset;
1184 return 0;
1185}
1186#endif /* CONFIG_PERF_EVENTS */
1187
1188static int
1189trace_uprobe_register(struct trace_event_call *event, enum trace_reg type,
1190 void *data)
1191{
1192 struct trace_uprobe *tu = event->data;
1193 struct trace_event_file *file = data;
1194
1195 switch (type) {
1196 case TRACE_REG_REGISTER:
1197 return probe_event_enable(tu, file, NULL);
1198
1199 case TRACE_REG_UNREGISTER:
1200 probe_event_disable(tu, file);
1201 return 0;
1202
1203#ifdef CONFIG_PERF_EVENTS
1204 case TRACE_REG_PERF_REGISTER:
1205 return probe_event_enable(tu, NULL, uprobe_perf_filter);
1206
1207 case TRACE_REG_PERF_UNREGISTER:
1208 probe_event_disable(tu, NULL);
1209 return 0;
1210
1211 case TRACE_REG_PERF_OPEN:
1212 return uprobe_perf_open(tu, data);
1213
1214 case TRACE_REG_PERF_CLOSE:
1215 return uprobe_perf_close(tu, data);
1216
1217#endif
1218 default:
1219 return 0;
1220 }
1221 return 0;
1222}
1223
1224static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
1225{
1226 struct trace_uprobe *tu;
1227 struct uprobe_dispatch_data udd;
1228 struct uprobe_cpu_buffer *ucb;
1229 int dsize, esize;
1230 int ret = 0;
1231
1232
1233 tu = container_of(con, struct trace_uprobe, consumer);
1234 tu->nhit++;
1235
1236 udd.tu = tu;
1237 udd.bp_addr = instruction_pointer(regs);
1238
1239 current->utask->vaddr = (unsigned long) &udd;
1240
1241 if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1242 return 0;
1243
1244 dsize = __get_data_size(&tu->tp, regs);
1245 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1246
1247 ucb = uprobe_buffer_get();
1248 store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize);
1249
1250 if (tu->tp.flags & TP_FLAG_TRACE)
1251 ret |= uprobe_trace_func(tu, regs, ucb, dsize);
1252
1253#ifdef CONFIG_PERF_EVENTS
1254 if (tu->tp.flags & TP_FLAG_PROFILE)
1255 ret |= uprobe_perf_func(tu, regs, ucb, dsize);
1256#endif
1257 uprobe_buffer_put(ucb);
1258 return ret;
1259}
1260
1261static int uretprobe_dispatcher(struct uprobe_consumer *con,
1262 unsigned long func, struct pt_regs *regs)
1263{
1264 struct trace_uprobe *tu;
1265 struct uprobe_dispatch_data udd;
1266 struct uprobe_cpu_buffer *ucb;
1267 int dsize, esize;
1268
1269 tu = container_of(con, struct trace_uprobe, consumer);
1270
1271 udd.tu = tu;
1272 udd.bp_addr = func;
1273
1274 current->utask->vaddr = (unsigned long) &udd;
1275
1276 if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1277 return 0;
1278
1279 dsize = __get_data_size(&tu->tp, regs);
1280 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1281
1282 ucb = uprobe_buffer_get();
1283 store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize);
1284
1285 if (tu->tp.flags & TP_FLAG_TRACE)
1286 uretprobe_trace_func(tu, func, regs, ucb, dsize);
1287
1288#ifdef CONFIG_PERF_EVENTS
1289 if (tu->tp.flags & TP_FLAG_PROFILE)
1290 uretprobe_perf_func(tu, func, regs, ucb, dsize);
1291#endif
1292 uprobe_buffer_put(ucb);
1293 return 0;
1294}
1295
1296static struct trace_event_functions uprobe_funcs = {
1297 .trace = print_uprobe_event
1298};
1299
1300static inline void init_trace_event_call(struct trace_uprobe *tu,
1301 struct trace_event_call *call)
1302{
1303 INIT_LIST_HEAD(&call->class->fields);
1304 call->event.funcs = &uprobe_funcs;
1305 call->class->define_fields = uprobe_event_define_fields;
1306
1307 call->flags = TRACE_EVENT_FL_UPROBE;
1308 call->class->reg = trace_uprobe_register;
1309 call->data = tu;
1310}
1311
1312static int register_uprobe_event(struct trace_uprobe *tu)
1313{
1314 struct trace_event_call *call = &tu->tp.call;
1315 int ret = 0;
1316
1317 init_trace_event_call(tu, call);
1318
1319 if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
1320 return -ENOMEM;
1321
1322 ret = register_trace_event(&call->event);
1323 if (!ret) {
1324 kfree(call->print_fmt);
1325 return -ENODEV;
1326 }
1327
1328 ret = trace_add_event_call(call);
1329
1330 if (ret) {
1331 pr_info("Failed to register uprobe event: %s\n",
1332 trace_event_name(call));
1333 kfree(call->print_fmt);
1334 unregister_trace_event(&call->event);
1335 }
1336
1337 return ret;
1338}
1339
1340static int unregister_uprobe_event(struct trace_uprobe *tu)
1341{
1342 int ret;
1343
1344 /* tu->event is unregistered in trace_remove_event_call() */
1345 ret = trace_remove_event_call(&tu->tp.call);
1346 if (ret)
1347 return ret;
1348 kfree(tu->tp.call.print_fmt);
1349 tu->tp.call.print_fmt = NULL;
1350 return 0;
1351}
1352
1353#ifdef CONFIG_PERF_EVENTS
1354struct trace_event_call *
1355create_local_trace_uprobe(char *name, unsigned long offs,
1356 unsigned long ref_ctr_offset, bool is_return)
1357{
1358 struct trace_uprobe *tu;
1359 struct path path;
1360 int ret;
1361
1362 ret = kern_path(name, LOOKUP_FOLLOW, &path);
1363 if (ret)
1364 return ERR_PTR(ret);
1365
1366 if (!d_is_reg(path.dentry)) {
1367 path_put(&path);
1368 return ERR_PTR(-EINVAL);
1369 }
1370
1371 /*
1372 * local trace_kprobes are not added to dyn_event, so they are never
1373 * searched in find_trace_kprobe(). Therefore, there is no concern of
1374 * duplicated name "DUMMY_EVENT" here.
1375 */
1376 tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0,
1377 is_return);
1378
1379 if (IS_ERR(tu)) {
1380 pr_info("Failed to allocate trace_uprobe.(%d)\n",
1381 (int)PTR_ERR(tu));
1382 path_put(&path);
1383 return ERR_CAST(tu);
1384 }
1385
1386 tu->offset = offs;
1387 tu->path = path;
1388 tu->ref_ctr_offset = ref_ctr_offset;
1389 tu->filename = kstrdup(name, GFP_KERNEL);
1390 init_trace_event_call(tu, &tu->tp.call);
1391
1392 if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) {
1393 ret = -ENOMEM;
1394 goto error;
1395 }
1396
1397 return &tu->tp.call;
1398error:
1399 free_trace_uprobe(tu);
1400 return ERR_PTR(ret);
1401}
1402
1403void destroy_local_trace_uprobe(struct trace_event_call *event_call)
1404{
1405 struct trace_uprobe *tu;
1406
1407 tu = container_of(event_call, struct trace_uprobe, tp.call);
1408
1409 kfree(tu->tp.call.print_fmt);
1410 tu->tp.call.print_fmt = NULL;
1411
1412 free_trace_uprobe(tu);
1413}
1414#endif /* CONFIG_PERF_EVENTS */
1415
1416/* Make a trace interface for controling probe points */
1417static __init int init_uprobe_trace(void)
1418{
1419 struct dentry *d_tracer;
1420 int ret;
1421
1422 ret = dyn_event_register(&trace_uprobe_ops);
1423 if (ret)
1424 return ret;
1425
1426 d_tracer = tracing_init_dentry();
1427 if (IS_ERR(d_tracer))
1428 return 0;
1429
1430 trace_create_file("uprobe_events", 0644, d_tracer,
1431 NULL, &uprobe_events_ops);
1432 /* Profile interface */
1433 trace_create_file("uprobe_profile", 0444, d_tracer,
1434 NULL, &uprobe_profile_ops);
1435 return 0;
1436}
1437
1438fs_initcall(init_uprobe_trace);
1439