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Commit | Line | Data |
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1b29b018 SR |
1 | /* |
2 | * ring buffer based function tracer | |
3 | * | |
4 | * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> | |
5 | * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com> | |
6 | * | |
7 | * Based on code from the latency_tracer, that is: | |
8 | * | |
9 | * Copyright (C) 2004-2006 Ingo Molnar | |
10 | * Copyright (C) 2004 William Lee Irwin III | |
11 | */ | |
23b4ff3a | 12 | #include <linux/ring_buffer.h> |
1b29b018 SR |
13 | #include <linux/debugfs.h> |
14 | #include <linux/uaccess.h> | |
15 | #include <linux/ftrace.h> | |
2e0f5761 | 16 | #include <linux/fs.h> |
1b29b018 SR |
17 | |
18 | #include "trace.h" | |
19 | ||
a225cdd2 SR |
20 | /* function tracing enabled */ |
21 | static int ftrace_function_enabled; | |
22 | ||
53614991 SR |
23 | static struct trace_array *func_trace; |
24 | ||
a225cdd2 SR |
25 | static void tracing_start_function_trace(void); |
26 | static void tracing_stop_function_trace(void); | |
27 | ||
b6f11df2 | 28 | static int function_trace_init(struct trace_array *tr) |
1b29b018 | 29 | { |
bb3c3c95 | 30 | func_trace = tr; |
26bc83f4 | 31 | tr->cpu = get_cpu(); |
26bc83f4 SR |
32 | put_cpu(); |
33 | ||
41bc8144 | 34 | tracing_start_cmdline_record(); |
1b29b018 | 35 | tracing_start_function_trace(); |
1c80025a | 36 | return 0; |
1b29b018 SR |
37 | } |
38 | ||
e309b41d | 39 | static void function_trace_reset(struct trace_array *tr) |
1b29b018 | 40 | { |
b6f11df2 ACM |
41 | tracing_stop_function_trace(); |
42 | tracing_stop_cmdline_record(); | |
1b29b018 SR |
43 | } |
44 | ||
9036990d SR |
45 | static void function_trace_start(struct trace_array *tr) |
46 | { | |
213cc060 | 47 | tracing_reset_online_cpus(tr); |
9036990d SR |
48 | } |
49 | ||
bb3c3c95 | 50 | static void |
2f5f6ad9 | 51 | function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip, |
a1e2e31d | 52 | struct ftrace_ops *op, struct pt_regs *pt_regs) |
bb3c3c95 SR |
53 | { |
54 | struct trace_array *tr = func_trace; | |
55 | struct trace_array_cpu *data; | |
56 | unsigned long flags; | |
57 | long disabled; | |
5168ae50 | 58 | int cpu; |
bb3c3c95 SR |
59 | int pc; |
60 | ||
61 | if (unlikely(!ftrace_function_enabled)) | |
62 | return; | |
63 | ||
64 | pc = preempt_count(); | |
5168ae50 | 65 | preempt_disable_notrace(); |
bb3c3c95 SR |
66 | local_save_flags(flags); |
67 | cpu = raw_smp_processor_id(); | |
68 | data = tr->data[cpu]; | |
69 | disabled = atomic_inc_return(&data->disabled); | |
70 | ||
71 | if (likely(disabled == 1)) | |
7be42151 | 72 | trace_function(tr, ip, parent_ip, flags, pc); |
bb3c3c95 SR |
73 | |
74 | atomic_dec(&data->disabled); | |
5168ae50 | 75 | preempt_enable_notrace(); |
bb3c3c95 SR |
76 | } |
77 | ||
65f8c95e | 78 | /* Our option */ |
21f67940 AV |
79 | enum { |
80 | TRACE_FUNC_OPT_STACK = 0x1, | |
21f67940 AV |
81 | }; |
82 | ||
83 | static struct tracer_flags func_flags; | |
84 | ||
bb3c3c95 | 85 | static void |
2f5f6ad9 | 86 | function_trace_call(unsigned long ip, unsigned long parent_ip, |
a1e2e31d SR |
87 | struct ftrace_ops *op, struct pt_regs *pt_regs) |
88 | ||
bb3c3c95 SR |
89 | { |
90 | struct trace_array *tr = func_trace; | |
91 | struct trace_array_cpu *data; | |
92 | unsigned long flags; | |
93 | long disabled; | |
94 | int cpu; | |
95 | int pc; | |
96 | ||
97 | if (unlikely(!ftrace_function_enabled)) | |
98 | return; | |
99 | ||
100 | /* | |
101 | * Need to use raw, since this must be called before the | |
102 | * recursive protection is performed. | |
103 | */ | |
104 | local_irq_save(flags); | |
105 | cpu = raw_smp_processor_id(); | |
106 | data = tr->data[cpu]; | |
107 | disabled = atomic_inc_return(&data->disabled); | |
108 | ||
109 | if (likely(disabled == 1)) { | |
110 | pc = preempt_count(); | |
7be42151 | 111 | trace_function(tr, ip, parent_ip, flags, pc); |
bb3c3c95 SR |
112 | } |
113 | ||
114 | atomic_dec(&data->disabled); | |
115 | local_irq_restore(flags); | |
116 | } | |
117 | ||
53614991 | 118 | static void |
2f5f6ad9 | 119 | function_stack_trace_call(unsigned long ip, unsigned long parent_ip, |
a1e2e31d | 120 | struct ftrace_ops *op, struct pt_regs *pt_regs) |
53614991 SR |
121 | { |
122 | struct trace_array *tr = func_trace; | |
123 | struct trace_array_cpu *data; | |
124 | unsigned long flags; | |
125 | long disabled; | |
126 | int cpu; | |
127 | int pc; | |
128 | ||
129 | if (unlikely(!ftrace_function_enabled)) | |
130 | return; | |
131 | ||
132 | /* | |
133 | * Need to use raw, since this must be called before the | |
134 | * recursive protection is performed. | |
135 | */ | |
136 | local_irq_save(flags); | |
137 | cpu = raw_smp_processor_id(); | |
138 | data = tr->data[cpu]; | |
139 | disabled = atomic_inc_return(&data->disabled); | |
140 | ||
141 | if (likely(disabled == 1)) { | |
142 | pc = preempt_count(); | |
7be42151 | 143 | trace_function(tr, ip, parent_ip, flags, pc); |
53614991 SR |
144 | /* |
145 | * skip over 5 funcs: | |
146 | * __ftrace_trace_stack, | |
147 | * __trace_stack, | |
148 | * function_stack_trace_call | |
149 | * ftrace_list_func | |
150 | * ftrace_call | |
151 | */ | |
7be42151 | 152 | __trace_stack(tr, flags, 5, pc); |
53614991 SR |
153 | } |
154 | ||
155 | atomic_dec(&data->disabled); | |
156 | local_irq_restore(flags); | |
157 | } | |
158 | ||
bb3c3c95 SR |
159 | |
160 | static struct ftrace_ops trace_ops __read_mostly = | |
161 | { | |
162 | .func = function_trace_call, | |
4740974a | 163 | .flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE, |
bb3c3c95 SR |
164 | }; |
165 | ||
53614991 SR |
166 | static struct ftrace_ops trace_stack_ops __read_mostly = |
167 | { | |
168 | .func = function_stack_trace_call, | |
4740974a | 169 | .flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE, |
53614991 SR |
170 | }; |
171 | ||
53614991 SR |
172 | static struct tracer_opt func_opts[] = { |
173 | #ifdef CONFIG_STACKTRACE | |
174 | { TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) }, | |
175 | #endif | |
176 | { } /* Always set a last empty entry */ | |
177 | }; | |
178 | ||
179 | static struct tracer_flags func_flags = { | |
180 | .val = 0, /* By default: all flags disabled */ | |
181 | .opts = func_opts | |
182 | }; | |
183 | ||
a225cdd2 | 184 | static void tracing_start_function_trace(void) |
3eb36aa0 SR |
185 | { |
186 | ftrace_function_enabled = 0; | |
187 | ||
188 | if (trace_flags & TRACE_ITER_PREEMPTONLY) | |
189 | trace_ops.func = function_trace_call_preempt_only; | |
190 | else | |
191 | trace_ops.func = function_trace_call; | |
192 | ||
193 | if (func_flags.val & TRACE_FUNC_OPT_STACK) | |
194 | register_ftrace_function(&trace_stack_ops); | |
195 | else | |
196 | register_ftrace_function(&trace_ops); | |
197 | ||
198 | ftrace_function_enabled = 1; | |
199 | } | |
200 | ||
a225cdd2 | 201 | static void tracing_stop_function_trace(void) |
3eb36aa0 SR |
202 | { |
203 | ftrace_function_enabled = 0; | |
c85a17e2 FW |
204 | |
205 | if (func_flags.val & TRACE_FUNC_OPT_STACK) | |
206 | unregister_ftrace_function(&trace_stack_ops); | |
207 | else | |
208 | unregister_ftrace_function(&trace_ops); | |
3eb36aa0 SR |
209 | } |
210 | ||
53614991 SR |
211 | static int func_set_flag(u32 old_flags, u32 bit, int set) |
212 | { | |
f555f123 AV |
213 | switch (bit) { |
214 | case TRACE_FUNC_OPT_STACK: | |
53614991 SR |
215 | /* do nothing if already set */ |
216 | if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK)) | |
f555f123 | 217 | break; |
53614991 | 218 | |
3eb36aa0 SR |
219 | if (set) { |
220 | unregister_ftrace_function(&trace_ops); | |
53614991 | 221 | register_ftrace_function(&trace_stack_ops); |
3eb36aa0 | 222 | } else { |
53614991 | 223 | unregister_ftrace_function(&trace_stack_ops); |
3eb36aa0 SR |
224 | register_ftrace_function(&trace_ops); |
225 | } | |
53614991 | 226 | |
f555f123 AV |
227 | break; |
228 | default: | |
229 | return -EINVAL; | |
53614991 SR |
230 | } |
231 | ||
f555f123 | 232 | return 0; |
53614991 SR |
233 | } |
234 | ||
1b29b018 SR |
235 | static struct tracer function_trace __read_mostly = |
236 | { | |
3eb36aa0 SR |
237 | .name = "function", |
238 | .init = function_trace_init, | |
239 | .reset = function_trace_reset, | |
240 | .start = function_trace_start, | |
6eaaa5d5 | 241 | .wait_pipe = poll_wait_pipe, |
53614991 SR |
242 | .flags = &func_flags, |
243 | .set_flag = func_set_flag, | |
60a11774 | 244 | #ifdef CONFIG_FTRACE_SELFTEST |
3eb36aa0 | 245 | .selftest = trace_selftest_startup_function, |
60a11774 | 246 | #endif |
1b29b018 SR |
247 | }; |
248 | ||
23b4ff3a SR |
249 | #ifdef CONFIG_DYNAMIC_FTRACE |
250 | static void | |
251 | ftrace_traceon(unsigned long ip, unsigned long parent_ip, void **data) | |
252 | { | |
253 | long *count = (long *)data; | |
254 | ||
255 | if (tracing_is_on()) | |
256 | return; | |
257 | ||
258 | if (!*count) | |
259 | return; | |
260 | ||
261 | if (*count != -1) | |
262 | (*count)--; | |
263 | ||
264 | tracing_on(); | |
265 | } | |
266 | ||
267 | static void | |
268 | ftrace_traceoff(unsigned long ip, unsigned long parent_ip, void **data) | |
269 | { | |
270 | long *count = (long *)data; | |
271 | ||
272 | if (!tracing_is_on()) | |
273 | return; | |
274 | ||
275 | if (!*count) | |
276 | return; | |
277 | ||
278 | if (*count != -1) | |
279 | (*count)--; | |
280 | ||
281 | tracing_off(); | |
282 | } | |
283 | ||
e110e3d1 SR |
284 | static int |
285 | ftrace_trace_onoff_print(struct seq_file *m, unsigned long ip, | |
b6887d79 | 286 | struct ftrace_probe_ops *ops, void *data); |
e110e3d1 | 287 | |
b6887d79 | 288 | static struct ftrace_probe_ops traceon_probe_ops = { |
23b4ff3a | 289 | .func = ftrace_traceon, |
e110e3d1 | 290 | .print = ftrace_trace_onoff_print, |
23b4ff3a SR |
291 | }; |
292 | ||
b6887d79 | 293 | static struct ftrace_probe_ops traceoff_probe_ops = { |
23b4ff3a | 294 | .func = ftrace_traceoff, |
e110e3d1 | 295 | .print = ftrace_trace_onoff_print, |
23b4ff3a SR |
296 | }; |
297 | ||
e110e3d1 SR |
298 | static int |
299 | ftrace_trace_onoff_print(struct seq_file *m, unsigned long ip, | |
b6887d79 | 300 | struct ftrace_probe_ops *ops, void *data) |
e110e3d1 | 301 | { |
e110e3d1 SR |
302 | long count = (long)data; |
303 | ||
b375a11a | 304 | seq_printf(m, "%ps:", (void *)ip); |
e110e3d1 | 305 | |
b6887d79 | 306 | if (ops == &traceon_probe_ops) |
e110e3d1 SR |
307 | seq_printf(m, "traceon"); |
308 | else | |
309 | seq_printf(m, "traceoff"); | |
310 | ||
35ebf1ca SR |
311 | if (count == -1) |
312 | seq_printf(m, ":unlimited\n"); | |
313 | else | |
00e54d08 | 314 | seq_printf(m, ":count=%ld\n", count); |
e110e3d1 SR |
315 | |
316 | return 0; | |
317 | } | |
318 | ||
23b4ff3a SR |
319 | static int |
320 | ftrace_trace_onoff_unreg(char *glob, char *cmd, char *param) | |
321 | { | |
b6887d79 | 322 | struct ftrace_probe_ops *ops; |
23b4ff3a SR |
323 | |
324 | /* we register both traceon and traceoff to this callback */ | |
325 | if (strcmp(cmd, "traceon") == 0) | |
b6887d79 | 326 | ops = &traceon_probe_ops; |
23b4ff3a | 327 | else |
b6887d79 | 328 | ops = &traceoff_probe_ops; |
23b4ff3a | 329 | |
b6887d79 | 330 | unregister_ftrace_function_probe_func(glob, ops); |
23b4ff3a SR |
331 | |
332 | return 0; | |
333 | } | |
334 | ||
335 | static int | |
43dd61c9 SR |
336 | ftrace_trace_onoff_callback(struct ftrace_hash *hash, |
337 | char *glob, char *cmd, char *param, int enable) | |
23b4ff3a | 338 | { |
b6887d79 | 339 | struct ftrace_probe_ops *ops; |
23b4ff3a SR |
340 | void *count = (void *)-1; |
341 | char *number; | |
342 | int ret; | |
343 | ||
344 | /* hash funcs only work with set_ftrace_filter */ | |
345 | if (!enable) | |
346 | return -EINVAL; | |
347 | ||
348 | if (glob[0] == '!') | |
349 | return ftrace_trace_onoff_unreg(glob+1, cmd, param); | |
350 | ||
351 | /* we register both traceon and traceoff to this callback */ | |
352 | if (strcmp(cmd, "traceon") == 0) | |
b6887d79 | 353 | ops = &traceon_probe_ops; |
23b4ff3a | 354 | else |
b6887d79 | 355 | ops = &traceoff_probe_ops; |
23b4ff3a SR |
356 | |
357 | if (!param) | |
358 | goto out_reg; | |
359 | ||
360 | number = strsep(¶m, ":"); | |
361 | ||
362 | if (!strlen(number)) | |
363 | goto out_reg; | |
364 | ||
365 | /* | |
366 | * We use the callback data field (which is a pointer) | |
367 | * as our counter. | |
368 | */ | |
369 | ret = strict_strtoul(number, 0, (unsigned long *)&count); | |
370 | if (ret) | |
371 | return ret; | |
372 | ||
373 | out_reg: | |
b6887d79 | 374 | ret = register_ftrace_function_probe(glob, ops, count); |
23b4ff3a | 375 | |
04aef32d | 376 | return ret < 0 ? ret : 0; |
23b4ff3a SR |
377 | } |
378 | ||
379 | static struct ftrace_func_command ftrace_traceon_cmd = { | |
380 | .name = "traceon", | |
381 | .func = ftrace_trace_onoff_callback, | |
382 | }; | |
383 | ||
384 | static struct ftrace_func_command ftrace_traceoff_cmd = { | |
385 | .name = "traceoff", | |
386 | .func = ftrace_trace_onoff_callback, | |
387 | }; | |
388 | ||
389 | static int __init init_func_cmd_traceon(void) | |
390 | { | |
391 | int ret; | |
392 | ||
393 | ret = register_ftrace_command(&ftrace_traceoff_cmd); | |
394 | if (ret) | |
395 | return ret; | |
396 | ||
397 | ret = register_ftrace_command(&ftrace_traceon_cmd); | |
398 | if (ret) | |
399 | unregister_ftrace_command(&ftrace_traceoff_cmd); | |
400 | return ret; | |
401 | } | |
402 | #else | |
403 | static inline int init_func_cmd_traceon(void) | |
404 | { | |
405 | return 0; | |
406 | } | |
407 | #endif /* CONFIG_DYNAMIC_FTRACE */ | |
408 | ||
1b29b018 SR |
409 | static __init int init_function_trace(void) |
410 | { | |
23b4ff3a | 411 | init_func_cmd_traceon(); |
1b29b018 SR |
412 | return register_tracer(&function_trace); |
413 | } | |
1b29b018 | 414 | device_initcall(init_function_trace); |
23b4ff3a | 415 |