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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 | |
6d49e352 | 10 | * Copyright (C) 2004 Nadia Yvette Chambers |
1b29b018 | 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; |
12883efb | 31 | tr->trace_buffer.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 | { | |
12883efb | 47 | tracing_reset_online_cpus(&tr->trace_buffer); |
9036990d SR |
48 | } |
49 | ||
65f8c95e | 50 | /* Our option */ |
21f67940 AV |
51 | enum { |
52 | TRACE_FUNC_OPT_STACK = 0x1, | |
21f67940 AV |
53 | }; |
54 | ||
55 | static struct tracer_flags func_flags; | |
56 | ||
bb3c3c95 | 57 | static void |
2f5f6ad9 | 58 | function_trace_call(unsigned long ip, unsigned long parent_ip, |
a1e2e31d | 59 | struct ftrace_ops *op, struct pt_regs *pt_regs) |
bb3c3c95 SR |
60 | { |
61 | struct trace_array *tr = func_trace; | |
62 | struct trace_array_cpu *data; | |
63 | unsigned long flags; | |
d41032a8 | 64 | int bit; |
bb3c3c95 SR |
65 | int cpu; |
66 | int pc; | |
67 | ||
68 | if (unlikely(!ftrace_function_enabled)) | |
69 | return; | |
70 | ||
897f68a4 SR |
71 | pc = preempt_count(); |
72 | preempt_disable_notrace(); | |
bb3c3c95 | 73 | |
897f68a4 SR |
74 | bit = trace_test_and_set_recursion(TRACE_FTRACE_START, TRACE_FTRACE_MAX); |
75 | if (bit < 0) | |
76 | goto out; | |
77 | ||
78 | cpu = smp_processor_id(); | |
12883efb | 79 | data = per_cpu_ptr(tr->trace_buffer.data, cpu); |
897f68a4 SR |
80 | if (!atomic_read(&data->disabled)) { |
81 | local_save_flags(flags); | |
7be42151 | 82 | trace_function(tr, ip, parent_ip, flags, pc); |
bb3c3c95 | 83 | } |
897f68a4 | 84 | trace_clear_recursion(bit); |
bb3c3c95 | 85 | |
897f68a4 SR |
86 | out: |
87 | preempt_enable_notrace(); | |
bb3c3c95 SR |
88 | } |
89 | ||
53614991 | 90 | static void |
2f5f6ad9 | 91 | function_stack_trace_call(unsigned long ip, unsigned long parent_ip, |
a1e2e31d | 92 | struct ftrace_ops *op, struct pt_regs *pt_regs) |
53614991 SR |
93 | { |
94 | struct trace_array *tr = func_trace; | |
95 | struct trace_array_cpu *data; | |
96 | unsigned long flags; | |
97 | long disabled; | |
98 | int cpu; | |
99 | int pc; | |
100 | ||
101 | if (unlikely(!ftrace_function_enabled)) | |
102 | return; | |
103 | ||
104 | /* | |
105 | * Need to use raw, since this must be called before the | |
106 | * recursive protection is performed. | |
107 | */ | |
108 | local_irq_save(flags); | |
109 | cpu = raw_smp_processor_id(); | |
12883efb | 110 | data = per_cpu_ptr(tr->trace_buffer.data, cpu); |
53614991 SR |
111 | disabled = atomic_inc_return(&data->disabled); |
112 | ||
113 | if (likely(disabled == 1)) { | |
114 | pc = preempt_count(); | |
7be42151 | 115 | trace_function(tr, ip, parent_ip, flags, pc); |
53614991 SR |
116 | /* |
117 | * skip over 5 funcs: | |
118 | * __ftrace_trace_stack, | |
119 | * __trace_stack, | |
120 | * function_stack_trace_call | |
121 | * ftrace_list_func | |
122 | * ftrace_call | |
123 | */ | |
7be42151 | 124 | __trace_stack(tr, flags, 5, pc); |
53614991 SR |
125 | } |
126 | ||
127 | atomic_dec(&data->disabled); | |
128 | local_irq_restore(flags); | |
129 | } | |
130 | ||
bb3c3c95 SR |
131 | |
132 | static struct ftrace_ops trace_ops __read_mostly = | |
133 | { | |
134 | .func = function_trace_call, | |
4740974a | 135 | .flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE, |
bb3c3c95 SR |
136 | }; |
137 | ||
53614991 SR |
138 | static struct ftrace_ops trace_stack_ops __read_mostly = |
139 | { | |
140 | .func = function_stack_trace_call, | |
4740974a | 141 | .flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE, |
53614991 SR |
142 | }; |
143 | ||
53614991 SR |
144 | static struct tracer_opt func_opts[] = { |
145 | #ifdef CONFIG_STACKTRACE | |
146 | { TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) }, | |
147 | #endif | |
148 | { } /* Always set a last empty entry */ | |
149 | }; | |
150 | ||
151 | static struct tracer_flags func_flags = { | |
152 | .val = 0, /* By default: all flags disabled */ | |
153 | .opts = func_opts | |
154 | }; | |
155 | ||
a225cdd2 | 156 | static void tracing_start_function_trace(void) |
3eb36aa0 SR |
157 | { |
158 | ftrace_function_enabled = 0; | |
159 | ||
3eb36aa0 SR |
160 | if (func_flags.val & TRACE_FUNC_OPT_STACK) |
161 | register_ftrace_function(&trace_stack_ops); | |
162 | else | |
163 | register_ftrace_function(&trace_ops); | |
164 | ||
165 | ftrace_function_enabled = 1; | |
166 | } | |
167 | ||
a225cdd2 | 168 | static void tracing_stop_function_trace(void) |
3eb36aa0 SR |
169 | { |
170 | ftrace_function_enabled = 0; | |
c85a17e2 FW |
171 | |
172 | if (func_flags.val & TRACE_FUNC_OPT_STACK) | |
173 | unregister_ftrace_function(&trace_stack_ops); | |
174 | else | |
175 | unregister_ftrace_function(&trace_ops); | |
3eb36aa0 SR |
176 | } |
177 | ||
53614991 SR |
178 | static int func_set_flag(u32 old_flags, u32 bit, int set) |
179 | { | |
f555f123 AV |
180 | switch (bit) { |
181 | case TRACE_FUNC_OPT_STACK: | |
53614991 SR |
182 | /* do nothing if already set */ |
183 | if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK)) | |
f555f123 | 184 | break; |
53614991 | 185 | |
3eb36aa0 SR |
186 | if (set) { |
187 | unregister_ftrace_function(&trace_ops); | |
53614991 | 188 | register_ftrace_function(&trace_stack_ops); |
3eb36aa0 | 189 | } else { |
53614991 | 190 | unregister_ftrace_function(&trace_stack_ops); |
3eb36aa0 SR |
191 | register_ftrace_function(&trace_ops); |
192 | } | |
53614991 | 193 | |
f555f123 AV |
194 | break; |
195 | default: | |
196 | return -EINVAL; | |
53614991 SR |
197 | } |
198 | ||
f555f123 | 199 | return 0; |
53614991 SR |
200 | } |
201 | ||
1b29b018 SR |
202 | static struct tracer function_trace __read_mostly = |
203 | { | |
3eb36aa0 SR |
204 | .name = "function", |
205 | .init = function_trace_init, | |
206 | .reset = function_trace_reset, | |
207 | .start = function_trace_start, | |
6eaaa5d5 | 208 | .wait_pipe = poll_wait_pipe, |
53614991 SR |
209 | .flags = &func_flags, |
210 | .set_flag = func_set_flag, | |
60a11774 | 211 | #ifdef CONFIG_FTRACE_SELFTEST |
3eb36aa0 | 212 | .selftest = trace_selftest_startup_function, |
60a11774 | 213 | #endif |
1b29b018 SR |
214 | }; |
215 | ||
23b4ff3a | 216 | #ifdef CONFIG_DYNAMIC_FTRACE |
1c317143 | 217 | static int update_count(void **data) |
23b4ff3a | 218 | { |
1c317143 | 219 | unsigned long *count = (long *)data; |
23b4ff3a SR |
220 | |
221 | if (!*count) | |
1c317143 | 222 | return 0; |
23b4ff3a SR |
223 | |
224 | if (*count != -1) | |
225 | (*count)--; | |
226 | ||
1c317143 | 227 | return 1; |
23b4ff3a SR |
228 | } |
229 | ||
230 | static void | |
1c317143 | 231 | ftrace_traceon(unsigned long ip, unsigned long parent_ip, void **data) |
23b4ff3a | 232 | { |
1c317143 | 233 | if (tracing_is_on()) |
23b4ff3a SR |
234 | return; |
235 | ||
1c317143 SRRH |
236 | if (update_count(data)) |
237 | tracing_on(); | |
238 | } | |
23b4ff3a | 239 | |
1c317143 SRRH |
240 | static void |
241 | ftrace_traceoff(unsigned long ip, unsigned long parent_ip, void **data) | |
242 | { | |
243 | if (!tracing_is_on()) | |
244 | return; | |
23b4ff3a | 245 | |
1c317143 SRRH |
246 | if (update_count(data)) |
247 | tracing_off(); | |
23b4ff3a SR |
248 | } |
249 | ||
e110e3d1 SR |
250 | static int |
251 | ftrace_trace_onoff_print(struct seq_file *m, unsigned long ip, | |
b6887d79 | 252 | struct ftrace_probe_ops *ops, void *data); |
e110e3d1 | 253 | |
b6887d79 | 254 | static struct ftrace_probe_ops traceon_probe_ops = { |
23b4ff3a | 255 | .func = ftrace_traceon, |
e110e3d1 | 256 | .print = ftrace_trace_onoff_print, |
23b4ff3a SR |
257 | }; |
258 | ||
b6887d79 | 259 | static struct ftrace_probe_ops traceoff_probe_ops = { |
23b4ff3a | 260 | .func = ftrace_traceoff, |
e110e3d1 | 261 | .print = ftrace_trace_onoff_print, |
23b4ff3a SR |
262 | }; |
263 | ||
e110e3d1 SR |
264 | static int |
265 | ftrace_trace_onoff_print(struct seq_file *m, unsigned long ip, | |
b6887d79 | 266 | struct ftrace_probe_ops *ops, void *data) |
e110e3d1 | 267 | { |
e110e3d1 SR |
268 | long count = (long)data; |
269 | ||
b375a11a | 270 | seq_printf(m, "%ps:", (void *)ip); |
e110e3d1 | 271 | |
b6887d79 | 272 | if (ops == &traceon_probe_ops) |
e110e3d1 SR |
273 | seq_printf(m, "traceon"); |
274 | else | |
275 | seq_printf(m, "traceoff"); | |
276 | ||
35ebf1ca SR |
277 | if (count == -1) |
278 | seq_printf(m, ":unlimited\n"); | |
279 | else | |
00e54d08 | 280 | seq_printf(m, ":count=%ld\n", count); |
e110e3d1 SR |
281 | |
282 | return 0; | |
283 | } | |
284 | ||
23b4ff3a | 285 | static int |
43dd61c9 SR |
286 | ftrace_trace_onoff_callback(struct ftrace_hash *hash, |
287 | char *glob, char *cmd, char *param, int enable) | |
23b4ff3a | 288 | { |
b6887d79 | 289 | struct ftrace_probe_ops *ops; |
23b4ff3a SR |
290 | void *count = (void *)-1; |
291 | char *number; | |
292 | int ret; | |
293 | ||
294 | /* hash funcs only work with set_ftrace_filter */ | |
295 | if (!enable) | |
296 | return -EINVAL; | |
297 | ||
23b4ff3a SR |
298 | /* we register both traceon and traceoff to this callback */ |
299 | if (strcmp(cmd, "traceon") == 0) | |
b6887d79 | 300 | ops = &traceon_probe_ops; |
23b4ff3a | 301 | else |
b6887d79 | 302 | ops = &traceoff_probe_ops; |
23b4ff3a | 303 | |
8b8fa62c SRRH |
304 | if (glob[0] == '!') { |
305 | unregister_ftrace_function_probe_func(glob+1, ops); | |
306 | return 0; | |
307 | } | |
308 | ||
23b4ff3a SR |
309 | if (!param) |
310 | goto out_reg; | |
311 | ||
312 | number = strsep(¶m, ":"); | |
313 | ||
314 | if (!strlen(number)) | |
315 | goto out_reg; | |
316 | ||
317 | /* | |
318 | * We use the callback data field (which is a pointer) | |
319 | * as our counter. | |
320 | */ | |
bcd83ea6 | 321 | ret = kstrtoul(number, 0, (unsigned long *)&count); |
23b4ff3a SR |
322 | if (ret) |
323 | return ret; | |
324 | ||
325 | out_reg: | |
b6887d79 | 326 | ret = register_ftrace_function_probe(glob, ops, count); |
23b4ff3a | 327 | |
04aef32d | 328 | return ret < 0 ? ret : 0; |
23b4ff3a SR |
329 | } |
330 | ||
331 | static struct ftrace_func_command ftrace_traceon_cmd = { | |
332 | .name = "traceon", | |
333 | .func = ftrace_trace_onoff_callback, | |
334 | }; | |
335 | ||
336 | static struct ftrace_func_command ftrace_traceoff_cmd = { | |
337 | .name = "traceoff", | |
338 | .func = ftrace_trace_onoff_callback, | |
339 | }; | |
340 | ||
341 | static int __init init_func_cmd_traceon(void) | |
342 | { | |
343 | int ret; | |
344 | ||
345 | ret = register_ftrace_command(&ftrace_traceoff_cmd); | |
346 | if (ret) | |
347 | return ret; | |
348 | ||
349 | ret = register_ftrace_command(&ftrace_traceon_cmd); | |
350 | if (ret) | |
351 | unregister_ftrace_command(&ftrace_traceoff_cmd); | |
352 | return ret; | |
353 | } | |
354 | #else | |
355 | static inline int init_func_cmd_traceon(void) | |
356 | { | |
357 | return 0; | |
358 | } | |
359 | #endif /* CONFIG_DYNAMIC_FTRACE */ | |
360 | ||
1b29b018 SR |
361 | static __init int init_function_trace(void) |
362 | { | |
23b4ff3a | 363 | init_func_cmd_traceon(); |
1b29b018 SR |
364 | return register_tracer(&function_trace); |
365 | } | |
6f415672 | 366 | core_initcall(init_function_trace); |