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Commit | Line | Data |
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47788c58 | 1 | #include <trace/syscall.h> |
1c569f02 | 2 | #include <trace/events/syscalls.h> |
ee08c6ec | 3 | #include <linux/kernel.h> |
fb34a08c | 4 | #include <linux/ftrace.h> |
cdd6c482 | 5 | #include <linux/perf_event.h> |
ee08c6ec FW |
6 | #include <asm/syscall.h> |
7 | ||
8 | #include "trace_output.h" | |
9 | #include "trace.h" | |
10 | ||
5be71b61 | 11 | static DEFINE_MUTEX(syscall_trace_lock); |
fb34a08c JB |
12 | static int sys_refcount_enter; |
13 | static int sys_refcount_exit; | |
57421dbb JB |
14 | static DECLARE_BITMAP(enabled_enter_syscalls, NR_syscalls); |
15 | static DECLARE_BITMAP(enabled_exit_syscalls, NR_syscalls); | |
ee08c6ec | 16 | |
c44fc770 FW |
17 | extern unsigned long __start_syscalls_metadata[]; |
18 | extern unsigned long __stop_syscalls_metadata[]; | |
19 | ||
20 | static struct syscall_metadata **syscalls_metadata; | |
21 | ||
22 | static struct syscall_metadata *find_syscall_meta(unsigned long syscall) | |
23 | { | |
24 | struct syscall_metadata *start; | |
25 | struct syscall_metadata *stop; | |
26 | char str[KSYM_SYMBOL_LEN]; | |
27 | ||
28 | ||
29 | start = (struct syscall_metadata *)__start_syscalls_metadata; | |
30 | stop = (struct syscall_metadata *)__stop_syscalls_metadata; | |
31 | kallsyms_lookup(syscall, NULL, NULL, NULL, str); | |
32 | ||
33 | for ( ; start < stop; start++) { | |
34 | /* | |
35 | * Only compare after the "sys" prefix. Archs that use | |
36 | * syscall wrappers may have syscalls symbols aliases prefixed | |
37 | * with "SyS" instead of "sys", leading to an unwanted | |
38 | * mismatch. | |
39 | */ | |
40 | if (start->name && !strcmp(start->name + 3, str + 3)) | |
41 | return start; | |
42 | } | |
43 | return NULL; | |
44 | } | |
45 | ||
46 | static struct syscall_metadata *syscall_nr_to_meta(int nr) | |
47 | { | |
48 | if (!syscalls_metadata || nr >= NR_syscalls || nr < 0) | |
49 | return NULL; | |
50 | ||
51 | return syscalls_metadata[nr]; | |
52 | } | |
53 | ||
bed1ffca FW |
54 | enum print_line_t |
55 | print_syscall_enter(struct trace_iterator *iter, int flags) | |
56 | { | |
57 | struct trace_seq *s = &iter->seq; | |
58 | struct trace_entry *ent = iter->ent; | |
59 | struct syscall_trace_enter *trace; | |
60 | struct syscall_metadata *entry; | |
61 | int i, ret, syscall; | |
62 | ||
64c12e04 | 63 | trace = (typeof(trace))ent; |
bed1ffca | 64 | syscall = trace->nr; |
bed1ffca | 65 | entry = syscall_nr_to_meta(syscall); |
64c12e04 | 66 | |
bed1ffca FW |
67 | if (!entry) |
68 | goto end; | |
69 | ||
fcc19438 | 70 | if (entry->enter_event->id != ent->type) { |
64c12e04 JB |
71 | WARN_ON_ONCE(1); |
72 | goto end; | |
73 | } | |
74 | ||
bed1ffca FW |
75 | ret = trace_seq_printf(s, "%s(", entry->name); |
76 | if (!ret) | |
77 | return TRACE_TYPE_PARTIAL_LINE; | |
78 | ||
79 | for (i = 0; i < entry->nb_args; i++) { | |
80 | /* parameter types */ | |
ba8b3a40 | 81 | if (trace_flags & TRACE_ITER_VERBOSE) { |
bed1ffca FW |
82 | ret = trace_seq_printf(s, "%s ", entry->types[i]); |
83 | if (!ret) | |
84 | return TRACE_TYPE_PARTIAL_LINE; | |
85 | } | |
86 | /* parameter values */ | |
4539f077 | 87 | ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i], |
bed1ffca | 88 | trace->args[i], |
4539f077 | 89 | i == entry->nb_args - 1 ? "" : ", "); |
bed1ffca FW |
90 | if (!ret) |
91 | return TRACE_TYPE_PARTIAL_LINE; | |
92 | } | |
93 | ||
4539f077 LZ |
94 | ret = trace_seq_putc(s, ')'); |
95 | if (!ret) | |
96 | return TRACE_TYPE_PARTIAL_LINE; | |
97 | ||
bed1ffca | 98 | end: |
4539f077 LZ |
99 | ret = trace_seq_putc(s, '\n'); |
100 | if (!ret) | |
101 | return TRACE_TYPE_PARTIAL_LINE; | |
102 | ||
bed1ffca FW |
103 | return TRACE_TYPE_HANDLED; |
104 | } | |
105 | ||
106 | enum print_line_t | |
107 | print_syscall_exit(struct trace_iterator *iter, int flags) | |
108 | { | |
109 | struct trace_seq *s = &iter->seq; | |
110 | struct trace_entry *ent = iter->ent; | |
111 | struct syscall_trace_exit *trace; | |
112 | int syscall; | |
113 | struct syscall_metadata *entry; | |
114 | int ret; | |
115 | ||
64c12e04 | 116 | trace = (typeof(trace))ent; |
bed1ffca | 117 | syscall = trace->nr; |
bed1ffca | 118 | entry = syscall_nr_to_meta(syscall); |
64c12e04 | 119 | |
bed1ffca FW |
120 | if (!entry) { |
121 | trace_seq_printf(s, "\n"); | |
122 | return TRACE_TYPE_HANDLED; | |
123 | } | |
124 | ||
fcc19438 | 125 | if (entry->exit_event->id != ent->type) { |
64c12e04 JB |
126 | WARN_ON_ONCE(1); |
127 | return TRACE_TYPE_UNHANDLED; | |
128 | } | |
129 | ||
bed1ffca FW |
130 | ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name, |
131 | trace->ret); | |
132 | if (!ret) | |
133 | return TRACE_TYPE_PARTIAL_LINE; | |
134 | ||
135 | return TRACE_TYPE_HANDLED; | |
136 | } | |
137 | ||
e6971969 LZ |
138 | extern char *__bad_type_size(void); |
139 | ||
140 | #define SYSCALL_FIELD(type, name) \ | |
141 | sizeof(type) != sizeof(trace.name) ? \ | |
142 | __bad_type_size() : \ | |
26a50744 TZ |
143 | #type, #name, offsetof(typeof(trace), name), \ |
144 | sizeof(trace.name), is_signed_type(type) | |
e6971969 | 145 | |
50307a45 LJ |
146 | static |
147 | int __set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len) | |
148 | { | |
149 | int i; | |
150 | int pos = 0; | |
151 | ||
152 | /* When len=0, we just calculate the needed length */ | |
153 | #define LEN_OR_ZERO (len ? len - pos : 0) | |
154 | ||
155 | pos += snprintf(buf + pos, LEN_OR_ZERO, "\""); | |
156 | for (i = 0; i < entry->nb_args; i++) { | |
157 | pos += snprintf(buf + pos, LEN_OR_ZERO, "%s: 0x%%0%zulx%s", | |
158 | entry->args[i], sizeof(unsigned long), | |
159 | i == entry->nb_args - 1 ? "" : ", "); | |
160 | } | |
161 | pos += snprintf(buf + pos, LEN_OR_ZERO, "\""); | |
162 | ||
163 | for (i = 0; i < entry->nb_args; i++) { | |
164 | pos += snprintf(buf + pos, LEN_OR_ZERO, | |
165 | ", ((unsigned long)(REC->%s))", entry->args[i]); | |
166 | } | |
167 | ||
168 | #undef LEN_OR_ZERO | |
169 | ||
170 | /* return the length of print_fmt */ | |
171 | return pos; | |
172 | } | |
173 | ||
174 | static int set_syscall_print_fmt(struct ftrace_event_call *call) | |
175 | { | |
176 | char *print_fmt; | |
177 | int len; | |
178 | struct syscall_metadata *entry = call->data; | |
179 | ||
180 | if (entry->enter_event != call) { | |
181 | call->print_fmt = "\"0x%lx\", REC->ret"; | |
182 | return 0; | |
183 | } | |
184 | ||
185 | /* First: called with 0 length to calculate the needed length */ | |
186 | len = __set_enter_print_fmt(entry, NULL, 0); | |
187 | ||
188 | print_fmt = kmalloc(len + 1, GFP_KERNEL); | |
189 | if (!print_fmt) | |
190 | return -ENOMEM; | |
191 | ||
192 | /* Second: actually write the @print_fmt */ | |
193 | __set_enter_print_fmt(entry, print_fmt, len + 1); | |
194 | call->print_fmt = print_fmt; | |
195 | ||
196 | return 0; | |
197 | } | |
198 | ||
199 | static void free_syscall_print_fmt(struct ftrace_event_call *call) | |
200 | { | |
201 | struct syscall_metadata *entry = call->data; | |
202 | ||
203 | if (entry->enter_event == call) | |
204 | kfree(call->print_fmt); | |
205 | } | |
206 | ||
540b7b8d LZ |
207 | int syscall_enter_define_fields(struct ftrace_event_call *call) |
208 | { | |
209 | struct syscall_trace_enter trace; | |
31c16b13 | 210 | struct syscall_metadata *meta = call->data; |
540b7b8d | 211 | int ret; |
540b7b8d LZ |
212 | int i; |
213 | int offset = offsetof(typeof(trace), args); | |
214 | ||
0f1ef51d LJ |
215 | ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER); |
216 | if (ret) | |
217 | return ret; | |
218 | ||
540b7b8d | 219 | for (i = 0; i < meta->nb_args; i++) { |
aeaeae11 FW |
220 | ret = trace_define_field(call, meta->types[i], |
221 | meta->args[i], offset, | |
43b51ead LZ |
222 | sizeof(unsigned long), 0, |
223 | FILTER_OTHER); | |
540b7b8d LZ |
224 | offset += sizeof(unsigned long); |
225 | } | |
226 | ||
227 | return ret; | |
228 | } | |
229 | ||
230 | int syscall_exit_define_fields(struct ftrace_event_call *call) | |
231 | { | |
232 | struct syscall_trace_exit trace; | |
233 | int ret; | |
234 | ||
0f1ef51d LJ |
235 | ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER); |
236 | if (ret) | |
237 | return ret; | |
238 | ||
26a50744 | 239 | ret = trace_define_field(call, SYSCALL_FIELD(long, ret), |
43b51ead | 240 | FILTER_OTHER); |
540b7b8d LZ |
241 | |
242 | return ret; | |
243 | } | |
244 | ||
fb34a08c | 245 | void ftrace_syscall_enter(struct pt_regs *regs, long id) |
ee08c6ec | 246 | { |
bed1ffca FW |
247 | struct syscall_trace_enter *entry; |
248 | struct syscall_metadata *sys_data; | |
249 | struct ring_buffer_event *event; | |
e77405ad | 250 | struct ring_buffer *buffer; |
bed1ffca | 251 | int size; |
ee08c6ec FW |
252 | int syscall_nr; |
253 | ||
254 | syscall_nr = syscall_get_nr(current, regs); | |
cd0980fc HB |
255 | if (syscall_nr < 0) |
256 | return; | |
fb34a08c JB |
257 | if (!test_bit(syscall_nr, enabled_enter_syscalls)) |
258 | return; | |
ee08c6ec | 259 | |
bed1ffca FW |
260 | sys_data = syscall_nr_to_meta(syscall_nr); |
261 | if (!sys_data) | |
262 | return; | |
263 | ||
264 | size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args; | |
265 | ||
fcc19438 LJ |
266 | event = trace_current_buffer_lock_reserve(&buffer, |
267 | sys_data->enter_event->id, size, 0, 0); | |
bed1ffca FW |
268 | if (!event) |
269 | return; | |
270 | ||
271 | entry = ring_buffer_event_data(event); | |
272 | entry->nr = syscall_nr; | |
273 | syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args); | |
274 | ||
e77405ad SR |
275 | if (!filter_current_check_discard(buffer, sys_data->enter_event, |
276 | entry, event)) | |
277 | trace_current_buffer_unlock_commit(buffer, event, 0, 0); | |
ee08c6ec FW |
278 | } |
279 | ||
fb34a08c | 280 | void ftrace_syscall_exit(struct pt_regs *regs, long ret) |
ee08c6ec | 281 | { |
bed1ffca FW |
282 | struct syscall_trace_exit *entry; |
283 | struct syscall_metadata *sys_data; | |
284 | struct ring_buffer_event *event; | |
e77405ad | 285 | struct ring_buffer *buffer; |
ee08c6ec FW |
286 | int syscall_nr; |
287 | ||
288 | syscall_nr = syscall_get_nr(current, regs); | |
cd0980fc HB |
289 | if (syscall_nr < 0) |
290 | return; | |
fb34a08c JB |
291 | if (!test_bit(syscall_nr, enabled_exit_syscalls)) |
292 | return; | |
ee08c6ec | 293 | |
bed1ffca FW |
294 | sys_data = syscall_nr_to_meta(syscall_nr); |
295 | if (!sys_data) | |
296 | return; | |
297 | ||
fcc19438 LJ |
298 | event = trace_current_buffer_lock_reserve(&buffer, |
299 | sys_data->exit_event->id, sizeof(*entry), 0, 0); | |
bed1ffca FW |
300 | if (!event) |
301 | return; | |
302 | ||
303 | entry = ring_buffer_event_data(event); | |
304 | entry->nr = syscall_nr; | |
305 | entry->ret = syscall_get_return_value(current, regs); | |
306 | ||
e77405ad SR |
307 | if (!filter_current_check_discard(buffer, sys_data->exit_event, |
308 | entry, event)) | |
309 | trace_current_buffer_unlock_commit(buffer, event, 0, 0); | |
ee08c6ec FW |
310 | } |
311 | ||
bd1a5c84 | 312 | int reg_event_syscall_enter(struct ftrace_event_call *call) |
ee08c6ec | 313 | { |
fb34a08c JB |
314 | int ret = 0; |
315 | int num; | |
fb34a08c | 316 | |
c252f657 | 317 | num = ((struct syscall_metadata *)call->data)->syscall_nr; |
57421dbb | 318 | if (num < 0 || num >= NR_syscalls) |
fb34a08c JB |
319 | return -ENOSYS; |
320 | mutex_lock(&syscall_trace_lock); | |
321 | if (!sys_refcount_enter) | |
1c569f02 | 322 | ret = register_trace_sys_enter(ftrace_syscall_enter); |
3b8e4273 | 323 | if (!ret) { |
fb34a08c JB |
324 | set_bit(num, enabled_enter_syscalls); |
325 | sys_refcount_enter++; | |
326 | } | |
327 | mutex_unlock(&syscall_trace_lock); | |
328 | return ret; | |
ee08c6ec FW |
329 | } |
330 | ||
bd1a5c84 | 331 | void unreg_event_syscall_enter(struct ftrace_event_call *call) |
ee08c6ec | 332 | { |
fb34a08c | 333 | int num; |
ee08c6ec | 334 | |
c252f657 | 335 | num = ((struct syscall_metadata *)call->data)->syscall_nr; |
57421dbb | 336 | if (num < 0 || num >= NR_syscalls) |
fb34a08c JB |
337 | return; |
338 | mutex_lock(&syscall_trace_lock); | |
339 | sys_refcount_enter--; | |
340 | clear_bit(num, enabled_enter_syscalls); | |
341 | if (!sys_refcount_enter) | |
1c569f02 | 342 | unregister_trace_sys_enter(ftrace_syscall_enter); |
fb34a08c JB |
343 | mutex_unlock(&syscall_trace_lock); |
344 | } | |
ee08c6ec | 345 | |
bd1a5c84 | 346 | int reg_event_syscall_exit(struct ftrace_event_call *call) |
ee08c6ec | 347 | { |
fb34a08c JB |
348 | int ret = 0; |
349 | int num; | |
fb34a08c | 350 | |
c252f657 | 351 | num = ((struct syscall_metadata *)call->data)->syscall_nr; |
57421dbb | 352 | if (num < 0 || num >= NR_syscalls) |
fb34a08c JB |
353 | return -ENOSYS; |
354 | mutex_lock(&syscall_trace_lock); | |
355 | if (!sys_refcount_exit) | |
1c569f02 | 356 | ret = register_trace_sys_exit(ftrace_syscall_exit); |
3b8e4273 | 357 | if (!ret) { |
fb34a08c JB |
358 | set_bit(num, enabled_exit_syscalls); |
359 | sys_refcount_exit++; | |
ee08c6ec | 360 | } |
fb34a08c JB |
361 | mutex_unlock(&syscall_trace_lock); |
362 | return ret; | |
363 | } | |
ee08c6ec | 364 | |
bd1a5c84 | 365 | void unreg_event_syscall_exit(struct ftrace_event_call *call) |
fb34a08c JB |
366 | { |
367 | int num; | |
ee08c6ec | 368 | |
c252f657 | 369 | num = ((struct syscall_metadata *)call->data)->syscall_nr; |
57421dbb | 370 | if (num < 0 || num >= NR_syscalls) |
fb34a08c JB |
371 | return; |
372 | mutex_lock(&syscall_trace_lock); | |
373 | sys_refcount_exit--; | |
374 | clear_bit(num, enabled_exit_syscalls); | |
375 | if (!sys_refcount_exit) | |
1c569f02 | 376 | unregister_trace_sys_exit(ftrace_syscall_exit); |
fb34a08c | 377 | mutex_unlock(&syscall_trace_lock); |
ee08c6ec | 378 | } |
fb34a08c | 379 | |
a1301da0 LJ |
380 | int init_syscall_trace(struct ftrace_event_call *call) |
381 | { | |
382 | int id; | |
383 | ||
50307a45 LJ |
384 | if (set_syscall_print_fmt(call) < 0) |
385 | return -ENOMEM; | |
386 | ||
c7ef3a90 SR |
387 | id = trace_event_raw_init(call); |
388 | ||
389 | if (id < 0) { | |
50307a45 | 390 | free_syscall_print_fmt(call); |
c7ef3a90 | 391 | return id; |
50307a45 | 392 | } |
c7ef3a90 SR |
393 | |
394 | return id; | |
a1301da0 LJ |
395 | } |
396 | ||
c44fc770 FW |
397 | int __init init_ftrace_syscalls(void) |
398 | { | |
399 | struct syscall_metadata *meta; | |
400 | unsigned long addr; | |
401 | int i; | |
402 | ||
403 | syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) * | |
404 | NR_syscalls, GFP_KERNEL); | |
405 | if (!syscalls_metadata) { | |
406 | WARN_ON(1); | |
407 | return -ENOMEM; | |
408 | } | |
409 | ||
410 | for (i = 0; i < NR_syscalls; i++) { | |
411 | addr = arch_syscall_addr(i); | |
412 | meta = find_syscall_meta(addr); | |
c252f657 LJ |
413 | if (!meta) |
414 | continue; | |
415 | ||
416 | meta->syscall_nr = i; | |
c44fc770 FW |
417 | syscalls_metadata[i] = meta; |
418 | } | |
419 | ||
420 | return 0; | |
421 | } | |
422 | core_initcall(init_ftrace_syscalls); | |
423 | ||
f4b5ffcc | 424 | #ifdef CONFIG_EVENT_PROFILE |
19007a67 | 425 | |
57421dbb JB |
426 | static DECLARE_BITMAP(enabled_prof_enter_syscalls, NR_syscalls); |
427 | static DECLARE_BITMAP(enabled_prof_exit_syscalls, NR_syscalls); | |
f4b5ffcc JB |
428 | static int sys_prof_refcount_enter; |
429 | static int sys_prof_refcount_exit; | |
430 | ||
431 | static void prof_syscall_enter(struct pt_regs *regs, long id) | |
432 | { | |
433 | struct syscall_metadata *sys_data; | |
20ab4425 FW |
434 | struct syscall_trace_enter *rec; |
435 | unsigned long flags; | |
ce71b9df | 436 | char *trace_buf; |
20ab4425 | 437 | char *raw_data; |
f4b5ffcc | 438 | int syscall_nr; |
4ed7c92d | 439 | int rctx; |
19007a67 | 440 | int size; |
20ab4425 | 441 | int cpu; |
f4b5ffcc JB |
442 | |
443 | syscall_nr = syscall_get_nr(current, regs); | |
444 | if (!test_bit(syscall_nr, enabled_prof_enter_syscalls)) | |
445 | return; | |
446 | ||
447 | sys_data = syscall_nr_to_meta(syscall_nr); | |
448 | if (!sys_data) | |
449 | return; | |
450 | ||
19007a67 FW |
451 | /* get the size after alignment with the u32 buffer size field */ |
452 | size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec); | |
453 | size = ALIGN(size + sizeof(u32), sizeof(u64)); | |
454 | size -= sizeof(u32); | |
455 | ||
20ab4425 FW |
456 | if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE, |
457 | "profile buffer not large enough")) | |
458 | return; | |
459 | ||
460 | /* Protect the per cpu buffer, begin the rcu read side */ | |
461 | local_irq_save(flags); | |
19007a67 | 462 | |
4ed7c92d PZ |
463 | rctx = perf_swevent_get_recursion_context(); |
464 | if (rctx < 0) | |
ce71b9df FW |
465 | goto end_recursion; |
466 | ||
20ab4425 FW |
467 | cpu = smp_processor_id(); |
468 | ||
28889bf9 | 469 | trace_buf = rcu_dereference(perf_trace_buf); |
20ab4425 | 470 | |
444a2a3b | 471 | if (!trace_buf) |
20ab4425 | 472 | goto end; |
19007a67 | 473 | |
ce71b9df | 474 | raw_data = per_cpu_ptr(trace_buf, cpu); |
20ab4425 FW |
475 | |
476 | /* zero the dead bytes from align to not leak stack to user */ | |
477 | *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL; | |
478 | ||
479 | rec = (struct syscall_trace_enter *) raw_data; | |
480 | tracing_generic_entry_update(&rec->ent, 0, 0); | |
fcc19438 | 481 | rec->ent.type = sys_data->enter_event->id; |
20ab4425 FW |
482 | rec->nr = syscall_nr; |
483 | syscall_get_arguments(current, regs, 0, sys_data->nb_args, | |
484 | (unsigned long *)&rec->args); | |
fcc19438 | 485 | perf_tp_event(sys_data->enter_event->id, 0, 1, rec, size); |
20ab4425 FW |
486 | |
487 | end: | |
4ed7c92d | 488 | perf_swevent_put_recursion_context(rctx); |
ce71b9df | 489 | end_recursion: |
20ab4425 | 490 | local_irq_restore(flags); |
f4b5ffcc JB |
491 | } |
492 | ||
3bbe84e9 | 493 | int prof_sysenter_enable(struct ftrace_event_call *call) |
f4b5ffcc JB |
494 | { |
495 | int ret = 0; | |
496 | int num; | |
497 | ||
3bbe84e9 | 498 | num = ((struct syscall_metadata *)call->data)->syscall_nr; |
f4b5ffcc JB |
499 | |
500 | mutex_lock(&syscall_trace_lock); | |
501 | if (!sys_prof_refcount_enter) | |
1c569f02 | 502 | ret = register_trace_sys_enter(prof_syscall_enter); |
f4b5ffcc JB |
503 | if (ret) { |
504 | pr_info("event trace: Could not activate" | |
505 | "syscall entry trace point"); | |
506 | } else { | |
507 | set_bit(num, enabled_prof_enter_syscalls); | |
508 | sys_prof_refcount_enter++; | |
509 | } | |
510 | mutex_unlock(&syscall_trace_lock); | |
511 | return ret; | |
512 | } | |
513 | ||
3bbe84e9 | 514 | void prof_sysenter_disable(struct ftrace_event_call *call) |
f4b5ffcc JB |
515 | { |
516 | int num; | |
517 | ||
3bbe84e9 | 518 | num = ((struct syscall_metadata *)call->data)->syscall_nr; |
f4b5ffcc JB |
519 | |
520 | mutex_lock(&syscall_trace_lock); | |
521 | sys_prof_refcount_enter--; | |
522 | clear_bit(num, enabled_prof_enter_syscalls); | |
523 | if (!sys_prof_refcount_enter) | |
1c569f02 | 524 | unregister_trace_sys_enter(prof_syscall_enter); |
f4b5ffcc JB |
525 | mutex_unlock(&syscall_trace_lock); |
526 | } | |
527 | ||
528 | static void prof_syscall_exit(struct pt_regs *regs, long ret) | |
529 | { | |
530 | struct syscall_metadata *sys_data; | |
20ab4425 FW |
531 | struct syscall_trace_exit *rec; |
532 | unsigned long flags; | |
f4b5ffcc | 533 | int syscall_nr; |
ce71b9df | 534 | char *trace_buf; |
20ab4425 | 535 | char *raw_data; |
4ed7c92d | 536 | int rctx; |
20ab4425 FW |
537 | int size; |
538 | int cpu; | |
f4b5ffcc JB |
539 | |
540 | syscall_nr = syscall_get_nr(current, regs); | |
541 | if (!test_bit(syscall_nr, enabled_prof_exit_syscalls)) | |
542 | return; | |
543 | ||
544 | sys_data = syscall_nr_to_meta(syscall_nr); | |
545 | if (!sys_data) | |
546 | return; | |
547 | ||
20ab4425 FW |
548 | /* We can probably do that at build time */ |
549 | size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64)); | |
550 | size -= sizeof(u32); | |
19007a67 | 551 | |
20ab4425 FW |
552 | /* |
553 | * Impossible, but be paranoid with the future | |
554 | * How to put this check outside runtime? | |
555 | */ | |
556 | if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE, | |
557 | "exit event has grown above profile buffer size")) | |
558 | return; | |
559 | ||
560 | /* Protect the per cpu buffer, begin the rcu read side */ | |
561 | local_irq_save(flags); | |
ce71b9df | 562 | |
4ed7c92d PZ |
563 | rctx = perf_swevent_get_recursion_context(); |
564 | if (rctx < 0) | |
ce71b9df FW |
565 | goto end_recursion; |
566 | ||
20ab4425 FW |
567 | cpu = smp_processor_id(); |
568 | ||
28889bf9 | 569 | trace_buf = rcu_dereference(perf_trace_buf); |
20ab4425 | 570 | |
444a2a3b | 571 | if (!trace_buf) |
20ab4425 FW |
572 | goto end; |
573 | ||
ce71b9df | 574 | raw_data = per_cpu_ptr(trace_buf, cpu); |
20ab4425 FW |
575 | |
576 | /* zero the dead bytes from align to not leak stack to user */ | |
577 | *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL; | |
578 | ||
579 | rec = (struct syscall_trace_exit *)raw_data; | |
580 | ||
581 | tracing_generic_entry_update(&rec->ent, 0, 0); | |
fcc19438 | 582 | rec->ent.type = sys_data->exit_event->id; |
20ab4425 FW |
583 | rec->nr = syscall_nr; |
584 | rec->ret = syscall_get_return_value(current, regs); | |
585 | ||
fcc19438 | 586 | perf_tp_event(sys_data->exit_event->id, 0, 1, rec, size); |
20ab4425 FW |
587 | |
588 | end: | |
4ed7c92d | 589 | perf_swevent_put_recursion_context(rctx); |
ce71b9df | 590 | end_recursion: |
20ab4425 | 591 | local_irq_restore(flags); |
f4b5ffcc JB |
592 | } |
593 | ||
3bbe84e9 | 594 | int prof_sysexit_enable(struct ftrace_event_call *call) |
f4b5ffcc JB |
595 | { |
596 | int ret = 0; | |
597 | int num; | |
598 | ||
3bbe84e9 | 599 | num = ((struct syscall_metadata *)call->data)->syscall_nr; |
f4b5ffcc JB |
600 | |
601 | mutex_lock(&syscall_trace_lock); | |
602 | if (!sys_prof_refcount_exit) | |
1c569f02 | 603 | ret = register_trace_sys_exit(prof_syscall_exit); |
f4b5ffcc JB |
604 | if (ret) { |
605 | pr_info("event trace: Could not activate" | |
606 | "syscall entry trace point"); | |
607 | } else { | |
608 | set_bit(num, enabled_prof_exit_syscalls); | |
609 | sys_prof_refcount_exit++; | |
610 | } | |
611 | mutex_unlock(&syscall_trace_lock); | |
612 | return ret; | |
613 | } | |
614 | ||
3bbe84e9 | 615 | void prof_sysexit_disable(struct ftrace_event_call *call) |
f4b5ffcc JB |
616 | { |
617 | int num; | |
618 | ||
3bbe84e9 | 619 | num = ((struct syscall_metadata *)call->data)->syscall_nr; |
f4b5ffcc JB |
620 | |
621 | mutex_lock(&syscall_trace_lock); | |
622 | sys_prof_refcount_exit--; | |
623 | clear_bit(num, enabled_prof_exit_syscalls); | |
624 | if (!sys_prof_refcount_exit) | |
1c569f02 | 625 | unregister_trace_sys_exit(prof_syscall_exit); |
f4b5ffcc JB |
626 | mutex_unlock(&syscall_trace_lock); |
627 | } | |
628 | ||
629 | #endif | |
630 | ||
631 |