trace_syscalls.c 10.1 KB
Newer Older
1
#include <trace/syscall.h>
2
#include <linux/kernel.h>
3
#include <linux/ftrace.h>
4
#include <linux/perf_counter.h>
5
6
7
8
9
#include <asm/syscall.h>

#include "trace_output.h"
#include "trace.h"

10
static DEFINE_MUTEX(syscall_trace_lock);
11
12
13
14
static int sys_refcount_enter;
static int sys_refcount_exit;
static DECLARE_BITMAP(enabled_enter_syscalls, FTRACE_SYSCALL_MAX);
static DECLARE_BITMAP(enabled_exit_syscalls, FTRACE_SYSCALL_MAX);
15

16
17
18
19
20
21
22
23
24
enum print_line_t
print_syscall_enter(struct trace_iterator *iter, int flags)
{
	struct trace_seq *s = &iter->seq;
	struct trace_entry *ent = iter->ent;
	struct syscall_trace_enter *trace;
	struct syscall_metadata *entry;
	int i, ret, syscall;

25
	trace = (typeof(trace))ent;
26
27
	syscall = trace->nr;
	entry = syscall_nr_to_meta(syscall);
28

29
30
31
	if (!entry)
		goto end;

32
33
34
35
36
	if (entry->enter_id != ent->type) {
		WARN_ON_ONCE(1);
		goto end;
	}

37
38
39
40
41
42
	ret = trace_seq_printf(s, "%s(", entry->name);
	if (!ret)
		return TRACE_TYPE_PARTIAL_LINE;

	for (i = 0; i < entry->nb_args; i++) {
		/* parameter types */
43
		if (trace_flags & TRACE_ITER_VERBOSE) {
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
			ret = trace_seq_printf(s, "%s ", entry->types[i]);
			if (!ret)
				return TRACE_TYPE_PARTIAL_LINE;
		}
		/* parameter values */
		ret = trace_seq_printf(s, "%s: %lx%s ", entry->args[i],
				       trace->args[i],
				       i == entry->nb_args - 1 ? ")" : ",");
		if (!ret)
			return TRACE_TYPE_PARTIAL_LINE;
	}

end:
	trace_seq_printf(s, "\n");
	return TRACE_TYPE_HANDLED;
}

enum print_line_t
print_syscall_exit(struct trace_iterator *iter, int flags)
{
	struct trace_seq *s = &iter->seq;
	struct trace_entry *ent = iter->ent;
	struct syscall_trace_exit *trace;
	int syscall;
	struct syscall_metadata *entry;
	int ret;

71
	trace = (typeof(trace))ent;
72
73
	syscall = trace->nr;
	entry = syscall_nr_to_meta(syscall);
74

75
76
77
78
79
	if (!entry) {
		trace_seq_printf(s, "\n");
		return TRACE_TYPE_HANDLED;
	}

80
81
82
83
84
	if (entry->exit_id != ent->type) {
		WARN_ON_ONCE(1);
		return TRACE_TYPE_UNHANDLED;
	}

85
86
87
88
89
90
91
92
	ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
				trace->ret);
	if (!ret)
		return TRACE_TYPE_PARTIAL_LINE;

	return TRACE_TYPE_HANDLED;
}

93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
int ftrace_format_syscall(struct ftrace_event_call *call, struct trace_seq *s)
{
	int i;
	int nr;
	int ret = 0;
	struct syscall_metadata *entry;
	int offset = sizeof(struct trace_entry);

	nr = syscall_name_to_nr((char *)call->data);
	entry = syscall_nr_to_meta(nr);

	if (!entry)
		return ret;

	for (i = 0; i < entry->nb_args; i++) {
		ret = trace_seq_printf(s, "\tfield:%s %s;", entry->types[i],
				        entry->args[i]);
		if (!ret)
			return 0;
		ret = trace_seq_printf(s, "\toffset:%d;\tsize:%lu;\n", offset,
				       sizeof(unsigned long));
		if (!ret)
			return 0;
		offset += sizeof(unsigned long);
	}

	trace_seq_printf(s, "\nprint fmt: \"");
	for (i = 0; i < entry->nb_args; i++) {
		ret = trace_seq_printf(s, "%s: 0x%%0%lulx%s", entry->args[i],
				        sizeof(unsigned long),
					i == entry->nb_args - 1 ? "\", " : ", ");
		if (!ret)
			return 0;
	}

	for (i = 0; i < entry->nb_args; i++) {
		ret = trace_seq_printf(s, "((unsigned long)(REC->%s))%s",
				        entry->args[i],
					i == entry->nb_args - 1 ? "\n" : ", ");
		if (!ret)
			return 0;
	}

	return ret;
}

139
void ftrace_syscall_enter(struct pt_regs *regs, long id)
140
{
141
142
143
144
	struct syscall_trace_enter *entry;
	struct syscall_metadata *sys_data;
	struct ring_buffer_event *event;
	int size;
145
146
147
	int syscall_nr;

	syscall_nr = syscall_get_nr(current, regs);
148
149
	if (!test_bit(syscall_nr, enabled_enter_syscalls))
		return;
150

151
152
153
154
155
156
	sys_data = syscall_nr_to_meta(syscall_nr);
	if (!sys_data)
		return;

	size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;

157
	event = trace_current_buffer_lock_reserve(sys_data->enter_id, size,
158
159
160
161
162
163
164
165
166
167
							0, 0);
	if (!event)
		return;

	entry = ring_buffer_event_data(event);
	entry->nr = syscall_nr;
	syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);

	trace_current_buffer_unlock_commit(event, 0, 0);
	trace_wake_up();
168
169
}

170
void ftrace_syscall_exit(struct pt_regs *regs, long ret)
171
{
172
173
174
	struct syscall_trace_exit *entry;
	struct syscall_metadata *sys_data;
	struct ring_buffer_event *event;
175
176
177
	int syscall_nr;

	syscall_nr = syscall_get_nr(current, regs);
178
179
	if (!test_bit(syscall_nr, enabled_exit_syscalls))
		return;
180

181
182
183
184
	sys_data = syscall_nr_to_meta(syscall_nr);
	if (!sys_data)
		return;

185
	event = trace_current_buffer_lock_reserve(sys_data->exit_id,
186
187
188
189
190
191
192
193
194
195
				sizeof(*entry), 0, 0);
	if (!event)
		return;

	entry = ring_buffer_event_data(event);
	entry->nr = syscall_nr;
	entry->ret = syscall_get_return_value(current, regs);

	trace_current_buffer_unlock_commit(event, 0, 0);
	trace_wake_up();
196
197
}

198
int reg_event_syscall_enter(void *ptr)
199
{
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
	int ret = 0;
	int num;
	char *name;

	name = (char *)ptr;
	num = syscall_name_to_nr(name);
	if (num < 0 || num >= FTRACE_SYSCALL_MAX)
		return -ENOSYS;
	mutex_lock(&syscall_trace_lock);
	if (!sys_refcount_enter)
		ret = register_trace_syscall_enter(ftrace_syscall_enter);
	if (ret) {
		pr_info("event trace: Could not activate"
				"syscall entry trace point");
	} else {
		set_bit(num, enabled_enter_syscalls);
		sys_refcount_enter++;
	}
	mutex_unlock(&syscall_trace_lock);
	return ret;
220
221
}

222
void unreg_event_syscall_enter(void *ptr)
223
{
224
225
	int num;
	char *name;
226

227
228
229
230
231
232
233
234
235
236
237
	name = (char *)ptr;
	num = syscall_name_to_nr(name);
	if (num < 0 || num >= FTRACE_SYSCALL_MAX)
		return;
	mutex_lock(&syscall_trace_lock);
	sys_refcount_enter--;
	clear_bit(num, enabled_enter_syscalls);
	if (!sys_refcount_enter)
		unregister_trace_syscall_enter(ftrace_syscall_enter);
	mutex_unlock(&syscall_trace_lock);
}
238

239
int reg_event_syscall_exit(void *ptr)
240
{
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
	int ret = 0;
	int num;
	char *name;

	name = (char *)ptr;
	num = syscall_name_to_nr(name);
	if (num < 0 || num >= FTRACE_SYSCALL_MAX)
		return -ENOSYS;
	mutex_lock(&syscall_trace_lock);
	if (!sys_refcount_exit)
		ret = register_trace_syscall_exit(ftrace_syscall_exit);
	if (ret) {
		pr_info("event trace: Could not activate"
				"syscall exit trace point");
	} else {
		set_bit(num, enabled_exit_syscalls);
		sys_refcount_exit++;
258
	}
259
260
261
	mutex_unlock(&syscall_trace_lock);
	return ret;
}
262

263
264
265
266
void unreg_event_syscall_exit(void *ptr)
{
	int num;
	char *name;
267

268
269
270
271
272
273
274
275
276
277
	name = (char *)ptr;
	num = syscall_name_to_nr(name);
	if (num < 0 || num >= FTRACE_SYSCALL_MAX)
		return;
	mutex_lock(&syscall_trace_lock);
	sys_refcount_exit--;
	clear_bit(num, enabled_exit_syscalls);
	if (!sys_refcount_exit)
		unregister_trace_syscall_exit(ftrace_syscall_exit);
	mutex_unlock(&syscall_trace_lock);
278
}
279
280
281
282
283
284
285
286

struct trace_event event_syscall_enter = {
	.trace			= print_syscall_enter,
};

struct trace_event event_syscall_exit = {
	.trace			= print_syscall_exit,
};
287
288

#ifdef CONFIG_EVENT_PROFILE
289
290
291
292
293
294
295
296
297
298
299

struct syscall_enter_record {
	struct trace_entry	entry;
	unsigned long		args[0];
};

struct syscall_exit_record {
	struct trace_entry	entry;
	unsigned long		ret;
};

300
301
302
303
304
305
306
static DECLARE_BITMAP(enabled_prof_enter_syscalls, FTRACE_SYSCALL_MAX);
static DECLARE_BITMAP(enabled_prof_exit_syscalls, FTRACE_SYSCALL_MAX);
static int sys_prof_refcount_enter;
static int sys_prof_refcount_exit;

static void prof_syscall_enter(struct pt_regs *regs, long id)
{
307
	struct syscall_enter_record *rec;
308
309
	struct syscall_metadata *sys_data;
	int syscall_nr;
310
	int size;
311
312
313
314
315
316
317
318
319

	syscall_nr = syscall_get_nr(current, regs);
	if (!test_bit(syscall_nr, enabled_prof_enter_syscalls))
		return;

	sys_data = syscall_nr_to_meta(syscall_nr);
	if (!sys_data)
		return;

320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
	/* get the size after alignment with the u32 buffer size field */
	size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
	size = ALIGN(size + sizeof(u32), sizeof(u64));
	size -= sizeof(u32);

	do {
		char raw_data[size];

		/* zero the dead bytes from align to not leak stack to user */
		*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;

		rec = (struct syscall_enter_record *) raw_data;
		tracing_generic_entry_update(&rec->entry, 0, 0);
		rec->entry.type = sys_data->enter_id;
		syscall_get_arguments(current, regs, 0, sys_data->nb_args,
				       (unsigned long *)&rec->args);
		perf_tpcounter_event(sys_data->enter_id, 0, 1, rec, size);
	} while(0);
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
}

int reg_prof_syscall_enter(char *name)
{
	int ret = 0;
	int num;

	num = syscall_name_to_nr(name);
	if (num < 0 || num >= FTRACE_SYSCALL_MAX)
		return -ENOSYS;

	mutex_lock(&syscall_trace_lock);
	if (!sys_prof_refcount_enter)
		ret = register_trace_syscall_enter(prof_syscall_enter);
	if (ret) {
		pr_info("event trace: Could not activate"
				"syscall entry trace point");
	} else {
		set_bit(num, enabled_prof_enter_syscalls);
		sys_prof_refcount_enter++;
	}
	mutex_unlock(&syscall_trace_lock);
	return ret;
}

void unreg_prof_syscall_enter(char *name)
{
	int num;

	num = syscall_name_to_nr(name);
	if (num < 0 || num >= FTRACE_SYSCALL_MAX)
		return;

	mutex_lock(&syscall_trace_lock);
	sys_prof_refcount_enter--;
	clear_bit(num, enabled_prof_enter_syscalls);
	if (!sys_prof_refcount_enter)
		unregister_trace_syscall_enter(prof_syscall_enter);
	mutex_unlock(&syscall_trace_lock);
}

static void prof_syscall_exit(struct pt_regs *regs, long ret)
{
	struct syscall_metadata *sys_data;
382
	struct syscall_exit_record rec;
383
384
385
386
387
388
389
390
391
392
	int syscall_nr;

	syscall_nr = syscall_get_nr(current, regs);
	if (!test_bit(syscall_nr, enabled_prof_exit_syscalls))
		return;

	sys_data = syscall_nr_to_meta(syscall_nr);
	if (!sys_data)
		return;

393
394
395
396
397
	tracing_generic_entry_update(&rec.entry, 0, 0);
	rec.entry.type = sys_data->exit_id;
	rec.ret = syscall_get_return_value(current, regs);

	perf_tpcounter_event(sys_data->exit_id, 0, 1, &rec, sizeof(rec));
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
}

int reg_prof_syscall_exit(char *name)
{
	int ret = 0;
	int num;

	num = syscall_name_to_nr(name);
	if (num < 0 || num >= FTRACE_SYSCALL_MAX)
		return -ENOSYS;

	mutex_lock(&syscall_trace_lock);
	if (!sys_prof_refcount_exit)
		ret = register_trace_syscall_exit(prof_syscall_exit);
	if (ret) {
		pr_info("event trace: Could not activate"
				"syscall entry trace point");
	} else {
		set_bit(num, enabled_prof_exit_syscalls);
		sys_prof_refcount_exit++;
	}
	mutex_unlock(&syscall_trace_lock);
	return ret;
}

void unreg_prof_syscall_exit(char *name)
{
	int num;

	num = syscall_name_to_nr(name);
	if (num < 0 || num >= FTRACE_SYSCALL_MAX)
		return;

	mutex_lock(&syscall_trace_lock);
	sys_prof_refcount_exit--;
	clear_bit(num, enabled_prof_exit_syscalls);
	if (!sys_prof_refcount_exit)
		unregister_trace_syscall_exit(prof_syscall_exit);
	mutex_unlock(&syscall_trace_lock);
}

#endif