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8#include <linux/module.h>
9#include <linux/kprobes.h>
10#include "trace.h"
11#include "trace_probe.h"
12
13static char __percpu *perf_trace_buf[PERF_NR_CONTEXTS];
14
15
16
17
18
19typedef typeof(unsigned long [PERF_MAX_TRACE_SIZE / sizeof(unsigned long)])
20 perf_trace_t;
21
22
23static int total_ref_count;
24
25static int perf_trace_event_perm(struct trace_event_call *tp_event,
26 struct perf_event *p_event)
27{
28 if (tp_event->perf_perm) {
29 int ret = tp_event->perf_perm(tp_event, p_event);
30 if (ret)
31 return ret;
32 }
33
34
35
36
37
38 if (p_event->parent)
39 return 0;
40
41
42
43
44
45
46
47 if (ftrace_event_is_function(tp_event)) {
48 if (perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN))
49 return -EPERM;
50
51 if (!is_sampling_event(p_event))
52 return 0;
53
54
55
56
57
58
59 if (!p_event->attr.exclude_callchain_user)
60 return -EINVAL;
61
62
63
64
65
66 if (p_event->attr.sample_type & PERF_SAMPLE_STACK_USER)
67 return -EINVAL;
68 }
69
70
71 if (!(p_event->attr.sample_type & PERF_SAMPLE_RAW))
72 return 0;
73
74
75 if (p_event->attach_state == PERF_ATTACH_TASK) {
76 if (tp_event->flags & TRACE_EVENT_FL_CAP_ANY)
77 return 0;
78 }
79
80
81
82
83
84 if (perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN))
85 return -EPERM;
86
87 return 0;
88}
89
90static int perf_trace_event_reg(struct trace_event_call *tp_event,
91 struct perf_event *p_event)
92{
93 struct hlist_head __percpu *list;
94 int ret = -ENOMEM;
95 int cpu;
96
97 p_event->tp_event = tp_event;
98 if (tp_event->perf_refcount++ > 0)
99 return 0;
100
101 list = alloc_percpu(struct hlist_head);
102 if (!list)
103 goto fail;
104
105 for_each_possible_cpu(cpu)
106 INIT_HLIST_HEAD(per_cpu_ptr(list, cpu));
107
108 tp_event->perf_events = list;
109
110 if (!total_ref_count) {
111 char __percpu *buf;
112 int i;
113
114 for (i = 0; i < PERF_NR_CONTEXTS; i++) {
115 buf = (char __percpu *)alloc_percpu(perf_trace_t);
116 if (!buf)
117 goto fail;
118
119 perf_trace_buf[i] = buf;
120 }
121 }
122
123 ret = tp_event->class->reg(tp_event, TRACE_REG_PERF_REGISTER, NULL);
124 if (ret)
125 goto fail;
126
127 total_ref_count++;
128 return 0;
129
130fail:
131 if (!total_ref_count) {
132 int i;
133
134 for (i = 0; i < PERF_NR_CONTEXTS; i++) {
135 free_percpu(perf_trace_buf[i]);
136 perf_trace_buf[i] = NULL;
137 }
138 }
139
140 if (!--tp_event->perf_refcount) {
141 free_percpu(tp_event->perf_events);
142 tp_event->perf_events = NULL;
143 }
144
145 return ret;
146}
147
148static void perf_trace_event_unreg(struct perf_event *p_event)
149{
150 struct trace_event_call *tp_event = p_event->tp_event;
151 int i;
152
153 if (--tp_event->perf_refcount > 0)
154 goto out;
155
156 tp_event->class->reg(tp_event, TRACE_REG_PERF_UNREGISTER, NULL);
157
158
159
160
161
162 tracepoint_synchronize_unregister();
163
164 free_percpu(tp_event->perf_events);
165 tp_event->perf_events = NULL;
166
167 if (!--total_ref_count) {
168 for (i = 0; i < PERF_NR_CONTEXTS; i++) {
169 free_percpu(perf_trace_buf[i]);
170 perf_trace_buf[i] = NULL;
171 }
172 }
173out:
174 module_put(tp_event->mod);
175}
176
177static int perf_trace_event_open(struct perf_event *p_event)
178{
179 struct trace_event_call *tp_event = p_event->tp_event;
180 return tp_event->class->reg(tp_event, TRACE_REG_PERF_OPEN, p_event);
181}
182
183static void perf_trace_event_close(struct perf_event *p_event)
184{
185 struct trace_event_call *tp_event = p_event->tp_event;
186 tp_event->class->reg(tp_event, TRACE_REG_PERF_CLOSE, p_event);
187}
188
189static int perf_trace_event_init(struct trace_event_call *tp_event,
190 struct perf_event *p_event)
191{
192 int ret;
193
194 ret = perf_trace_event_perm(tp_event, p_event);
195 if (ret)
196 return ret;
197
198 ret = perf_trace_event_reg(tp_event, p_event);
199 if (ret)
200 return ret;
201
202 ret = perf_trace_event_open(p_event);
203 if (ret) {
204 perf_trace_event_unreg(p_event);
205 return ret;
206 }
207
208 return 0;
209}
210
211int perf_trace_init(struct perf_event *p_event)
212{
213 struct trace_event_call *tp_event;
214 u64 event_id = p_event->attr.config;
215 int ret = -EINVAL;
216
217 mutex_lock(&event_mutex);
218 list_for_each_entry(tp_event, &ftrace_events, list) {
219 if (tp_event->event.type == event_id &&
220 tp_event->class && tp_event->class->reg &&
221 try_module_get(tp_event->mod)) {
222 ret = perf_trace_event_init(tp_event, p_event);
223 if (ret)
224 module_put(tp_event->mod);
225 break;
226 }
227 }
228 mutex_unlock(&event_mutex);
229
230 return ret;
231}
232
233void perf_trace_destroy(struct perf_event *p_event)
234{
235 mutex_lock(&event_mutex);
236 perf_trace_event_close(p_event);
237 perf_trace_event_unreg(p_event);
238 mutex_unlock(&event_mutex);
239}
240
241#ifdef CONFIG_KPROBE_EVENTS
242int perf_kprobe_init(struct perf_event *p_event, bool is_retprobe)
243{
244 int ret;
245 char *func = NULL;
246 struct trace_event_call *tp_event;
247
248 if (p_event->attr.kprobe_func) {
249 func = kzalloc(KSYM_NAME_LEN, GFP_KERNEL);
250 if (!func)
251 return -ENOMEM;
252 ret = strncpy_from_user(
253 func, u64_to_user_ptr(p_event->attr.kprobe_func),
254 KSYM_NAME_LEN);
255 if (ret == KSYM_NAME_LEN)
256 ret = -E2BIG;
257 if (ret < 0)
258 goto out;
259
260 if (func[0] == '\0') {
261 kfree(func);
262 func = NULL;
263 }
264 }
265
266 tp_event = create_local_trace_kprobe(
267 func, (void *)(unsigned long)(p_event->attr.kprobe_addr),
268 p_event->attr.probe_offset, is_retprobe);
269 if (IS_ERR(tp_event)) {
270 ret = PTR_ERR(tp_event);
271 goto out;
272 }
273
274 ret = perf_trace_event_init(tp_event, p_event);
275 if (ret)
276 destroy_local_trace_kprobe(tp_event);
277out:
278 kfree(func);
279 return ret;
280}
281
282void perf_kprobe_destroy(struct perf_event *p_event)
283{
284 perf_trace_event_close(p_event);
285 perf_trace_event_unreg(p_event);
286
287 destroy_local_trace_kprobe(p_event->tp_event);
288}
289#endif
290
291#ifdef CONFIG_UPROBE_EVENTS
292int perf_uprobe_init(struct perf_event *p_event, bool is_retprobe)
293{
294 int ret;
295 char *path = NULL;
296 struct trace_event_call *tp_event;
297
298 if (!p_event->attr.uprobe_path)
299 return -EINVAL;
300 path = kzalloc(PATH_MAX, GFP_KERNEL);
301 if (!path)
302 return -ENOMEM;
303 ret = strncpy_from_user(
304 path, u64_to_user_ptr(p_event->attr.uprobe_path), PATH_MAX);
305 if (ret == PATH_MAX)
306 return -E2BIG;
307 if (ret < 0)
308 goto out;
309 if (path[0] == '\0') {
310 ret = -EINVAL;
311 goto out;
312 }
313
314 tp_event = create_local_trace_uprobe(
315 path, p_event->attr.probe_offset, is_retprobe);
316 if (IS_ERR(tp_event)) {
317 ret = PTR_ERR(tp_event);
318 goto out;
319 }
320
321
322
323
324
325
326 mutex_lock(&event_mutex);
327 ret = perf_trace_event_init(tp_event, p_event);
328 if (ret)
329 destroy_local_trace_uprobe(tp_event);
330 mutex_unlock(&event_mutex);
331out:
332 kfree(path);
333 return ret;
334}
335
336void perf_uprobe_destroy(struct perf_event *p_event)
337{
338 mutex_lock(&event_mutex);
339 perf_trace_event_close(p_event);
340 perf_trace_event_unreg(p_event);
341 mutex_unlock(&event_mutex);
342 destroy_local_trace_uprobe(p_event->tp_event);
343}
344#endif
345
346int perf_trace_add(struct perf_event *p_event, int flags)
347{
348 struct trace_event_call *tp_event = p_event->tp_event;
349
350 if (!(flags & PERF_EF_START))
351 p_event->hw.state = PERF_HES_STOPPED;
352
353
354
355
356
357
358 if (!tp_event->class->reg(tp_event, TRACE_REG_PERF_ADD, p_event)) {
359 struct hlist_head __percpu *pcpu_list;
360 struct hlist_head *list;
361
362 pcpu_list = tp_event->perf_events;
363 if (WARN_ON_ONCE(!pcpu_list))
364 return -EINVAL;
365
366 list = this_cpu_ptr(pcpu_list);
367 hlist_add_head_rcu(&p_event->hlist_entry, list);
368 }
369
370 return 0;
371}
372
373void perf_trace_del(struct perf_event *p_event, int flags)
374{
375 struct trace_event_call *tp_event = p_event->tp_event;
376
377
378
379
380
381
382 if (!tp_event->class->reg(tp_event, TRACE_REG_PERF_DEL, p_event))
383 hlist_del_rcu(&p_event->hlist_entry);
384}
385
386void *perf_trace_buf_alloc(int size, struct pt_regs **regs, int *rctxp)
387{
388 char *raw_data;
389 int rctx;
390
391 BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(unsigned long));
392
393 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
394 "perf buffer not large enough"))
395 return NULL;
396
397 *rctxp = rctx = perf_swevent_get_recursion_context();
398 if (rctx < 0)
399 return NULL;
400
401 if (regs)
402 *regs = this_cpu_ptr(&__perf_regs[rctx]);
403 raw_data = this_cpu_ptr(perf_trace_buf[rctx]);
404
405
406 memset(&raw_data[size - sizeof(u64)], 0, sizeof(u64));
407 return raw_data;
408}
409EXPORT_SYMBOL_GPL(perf_trace_buf_alloc);
410NOKPROBE_SYMBOL(perf_trace_buf_alloc);
411
412void perf_trace_buf_update(void *record, u16 type)
413{
414 struct trace_entry *entry = record;
415 int pc = preempt_count();
416 unsigned long flags;
417
418 local_save_flags(flags);
419 tracing_generic_entry_update(entry, flags, pc);
420 entry->type = type;
421}
422NOKPROBE_SYMBOL(perf_trace_buf_update);
423
424#ifdef CONFIG_FUNCTION_TRACER
425static void
426perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip,
427 struct ftrace_ops *ops, struct pt_regs *pt_regs)
428{
429 struct ftrace_entry *entry;
430 struct perf_event *event;
431 struct hlist_head head;
432 struct pt_regs regs;
433 int rctx;
434
435 if ((unsigned long)ops->private != smp_processor_id())
436 return;
437
438 event = container_of(ops, struct perf_event, ftrace_ops);
439
440
441
442
443
444
445
446 head.first = &event->hlist_entry;
447
448#define ENTRY_SIZE (ALIGN(sizeof(struct ftrace_entry) + sizeof(u32), \
449 sizeof(u64)) - sizeof(u32))
450
451 BUILD_BUG_ON(ENTRY_SIZE > PERF_MAX_TRACE_SIZE);
452
453 memset(®s, 0, sizeof(regs));
454 perf_fetch_caller_regs(®s);
455
456 entry = perf_trace_buf_alloc(ENTRY_SIZE, NULL, &rctx);
457 if (!entry)
458 return;
459
460 entry->ip = ip;
461 entry->parent_ip = parent_ip;
462 perf_trace_buf_submit(entry, ENTRY_SIZE, rctx, TRACE_FN,
463 1, ®s, &head, NULL);
464
465#undef ENTRY_SIZE
466}
467
468static int perf_ftrace_function_register(struct perf_event *event)
469{
470 struct ftrace_ops *ops = &event->ftrace_ops;
471
472 ops->flags = FTRACE_OPS_FL_RCU;
473 ops->func = perf_ftrace_function_call;
474 ops->private = (void *)(unsigned long)nr_cpu_ids;
475
476 return register_ftrace_function(ops);
477}
478
479static int perf_ftrace_function_unregister(struct perf_event *event)
480{
481 struct ftrace_ops *ops = &event->ftrace_ops;
482 int ret = unregister_ftrace_function(ops);
483 ftrace_free_filter(ops);
484 return ret;
485}
486
487int perf_ftrace_event_register(struct trace_event_call *call,
488 enum trace_reg type, void *data)
489{
490 struct perf_event *event = data;
491
492 switch (type) {
493 case TRACE_REG_REGISTER:
494 case TRACE_REG_UNREGISTER:
495 break;
496 case TRACE_REG_PERF_REGISTER:
497 case TRACE_REG_PERF_UNREGISTER:
498 return 0;
499 case TRACE_REG_PERF_OPEN:
500 return perf_ftrace_function_register(data);
501 case TRACE_REG_PERF_CLOSE:
502 return perf_ftrace_function_unregister(data);
503 case TRACE_REG_PERF_ADD:
504 event->ftrace_ops.private = (void *)(unsigned long)smp_processor_id();
505 return 1;
506 case TRACE_REG_PERF_DEL:
507 event->ftrace_ops.private = (void *)(unsigned long)nr_cpu_ids;
508 return 1;
509 }
510
511 return -EINVAL;
512}
513#endif
514