tracing: Remove ftrace_preempt_disable/enable
[linux-2.6.git] / kernel / trace / trace_functions.c
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  */
12 #include <linux/ring_buffer.h>
13 #include <linux/debugfs.h>
14 #include <linux/uaccess.h>
15 #include <linux/ftrace.h>
16 #include <linux/fs.h>
17
18 #include "trace.h"
19
20 /* function tracing enabled */
21 static int                      ftrace_function_enabled;
22
23 static struct trace_array       *func_trace;
24
25 static void tracing_start_function_trace(void);
26 static void tracing_stop_function_trace(void);
27
28 static int function_trace_init(struct trace_array *tr)
29 {
30         func_trace = tr;
31         tr->cpu = get_cpu();
32         put_cpu();
33
34         tracing_start_cmdline_record();
35         tracing_start_function_trace();
36         return 0;
37 }
38
39 static void function_trace_reset(struct trace_array *tr)
40 {
41         tracing_stop_function_trace();
42         tracing_stop_cmdline_record();
43 }
44
45 static void function_trace_start(struct trace_array *tr)
46 {
47         tracing_reset_online_cpus(tr);
48 }
49
50 static void
51 function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip)
52 {
53         struct trace_array *tr = func_trace;
54         struct trace_array_cpu *data;
55         unsigned long flags;
56         long disabled;
57         int cpu;
58         int pc;
59
60         if (unlikely(!ftrace_function_enabled))
61                 return;
62
63         pc = preempt_count();
64         preempt_disable_notrace();
65         local_save_flags(flags);
66         cpu = raw_smp_processor_id();
67         data = tr->data[cpu];
68         disabled = atomic_inc_return(&data->disabled);
69
70         if (likely(disabled == 1))
71                 trace_function(tr, ip, parent_ip, flags, pc);
72
73         atomic_dec(&data->disabled);
74         preempt_enable_notrace();
75 }
76
77 static void
78 function_trace_call(unsigned long ip, unsigned long parent_ip)
79 {
80         struct trace_array *tr = func_trace;
81         struct trace_array_cpu *data;
82         unsigned long flags;
83         long disabled;
84         int cpu;
85         int pc;
86
87         if (unlikely(!ftrace_function_enabled))
88                 return;
89
90         /*
91          * Need to use raw, since this must be called before the
92          * recursive protection is performed.
93          */
94         local_irq_save(flags);
95         cpu = raw_smp_processor_id();
96         data = tr->data[cpu];
97         disabled = atomic_inc_return(&data->disabled);
98
99         if (likely(disabled == 1)) {
100                 pc = preempt_count();
101                 trace_function(tr, ip, parent_ip, flags, pc);
102         }
103
104         atomic_dec(&data->disabled);
105         local_irq_restore(flags);
106 }
107
108 static void
109 function_stack_trace_call(unsigned long ip, unsigned long parent_ip)
110 {
111         struct trace_array *tr = func_trace;
112         struct trace_array_cpu *data;
113         unsigned long flags;
114         long disabled;
115         int cpu;
116         int pc;
117
118         if (unlikely(!ftrace_function_enabled))
119                 return;
120
121         /*
122          * Need to use raw, since this must be called before the
123          * recursive protection is performed.
124          */
125         local_irq_save(flags);
126         cpu = raw_smp_processor_id();
127         data = tr->data[cpu];
128         disabled = atomic_inc_return(&data->disabled);
129
130         if (likely(disabled == 1)) {
131                 pc = preempt_count();
132                 trace_function(tr, ip, parent_ip, flags, pc);
133                 /*
134                  * skip over 5 funcs:
135                  *    __ftrace_trace_stack,
136                  *    __trace_stack,
137                  *    function_stack_trace_call
138                  *    ftrace_list_func
139                  *    ftrace_call
140                  */
141                 __trace_stack(tr, flags, 5, pc);
142         }
143
144         atomic_dec(&data->disabled);
145         local_irq_restore(flags);
146 }
147
148
149 static struct ftrace_ops trace_ops __read_mostly =
150 {
151         .func = function_trace_call,
152 };
153
154 static struct ftrace_ops trace_stack_ops __read_mostly =
155 {
156         .func = function_stack_trace_call,
157 };
158
159 /* Our two options */
160 enum {
161         TRACE_FUNC_OPT_STACK = 0x1,
162 };
163
164 static struct tracer_opt func_opts[] = {
165 #ifdef CONFIG_STACKTRACE
166         { TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) },
167 #endif
168         { } /* Always set a last empty entry */
169 };
170
171 static struct tracer_flags func_flags = {
172         .val = 0, /* By default: all flags disabled */
173         .opts = func_opts
174 };
175
176 static void tracing_start_function_trace(void)
177 {
178         ftrace_function_enabled = 0;
179
180         if (trace_flags & TRACE_ITER_PREEMPTONLY)
181                 trace_ops.func = function_trace_call_preempt_only;
182         else
183                 trace_ops.func = function_trace_call;
184
185         if (func_flags.val & TRACE_FUNC_OPT_STACK)
186                 register_ftrace_function(&trace_stack_ops);
187         else
188                 register_ftrace_function(&trace_ops);
189
190         ftrace_function_enabled = 1;
191 }
192
193 static void tracing_stop_function_trace(void)
194 {
195         ftrace_function_enabled = 0;
196
197         if (func_flags.val & TRACE_FUNC_OPT_STACK)
198                 unregister_ftrace_function(&trace_stack_ops);
199         else
200                 unregister_ftrace_function(&trace_ops);
201 }
202
203 static int func_set_flag(u32 old_flags, u32 bit, int set)
204 {
205         if (bit == TRACE_FUNC_OPT_STACK) {
206                 /* do nothing if already set */
207                 if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK))
208                         return 0;
209
210                 if (set) {
211                         unregister_ftrace_function(&trace_ops);
212                         register_ftrace_function(&trace_stack_ops);
213                 } else {
214                         unregister_ftrace_function(&trace_stack_ops);
215                         register_ftrace_function(&trace_ops);
216                 }
217
218                 return 0;
219         }
220
221         return -EINVAL;
222 }
223
224 static struct tracer function_trace __read_mostly =
225 {
226         .name           = "function",
227         .init           = function_trace_init,
228         .reset          = function_trace_reset,
229         .start          = function_trace_start,
230         .wait_pipe      = poll_wait_pipe,
231         .flags          = &func_flags,
232         .set_flag       = func_set_flag,
233 #ifdef CONFIG_FTRACE_SELFTEST
234         .selftest       = trace_selftest_startup_function,
235 #endif
236 };
237
238 #ifdef CONFIG_DYNAMIC_FTRACE
239 static void
240 ftrace_traceon(unsigned long ip, unsigned long parent_ip, void **data)
241 {
242         long *count = (long *)data;
243
244         if (tracing_is_on())
245                 return;
246
247         if (!*count)
248                 return;
249
250         if (*count != -1)
251                 (*count)--;
252
253         tracing_on();
254 }
255
256 static void
257 ftrace_traceoff(unsigned long ip, unsigned long parent_ip, void **data)
258 {
259         long *count = (long *)data;
260
261         if (!tracing_is_on())
262                 return;
263
264         if (!*count)
265                 return;
266
267         if (*count != -1)
268                 (*count)--;
269
270         tracing_off();
271 }
272
273 static int
274 ftrace_trace_onoff_print(struct seq_file *m, unsigned long ip,
275                          struct ftrace_probe_ops *ops, void *data);
276
277 static struct ftrace_probe_ops traceon_probe_ops = {
278         .func                   = ftrace_traceon,
279         .print                  = ftrace_trace_onoff_print,
280 };
281
282 static struct ftrace_probe_ops traceoff_probe_ops = {
283         .func                   = ftrace_traceoff,
284         .print                  = ftrace_trace_onoff_print,
285 };
286
287 static int
288 ftrace_trace_onoff_print(struct seq_file *m, unsigned long ip,
289                          struct ftrace_probe_ops *ops, void *data)
290 {
291         long count = (long)data;
292
293         seq_printf(m, "%ps:", (void *)ip);
294
295         if (ops == &traceon_probe_ops)
296                 seq_printf(m, "traceon");
297         else
298                 seq_printf(m, "traceoff");
299
300         if (count == -1)
301                 seq_printf(m, ":unlimited\n");
302         else
303                 seq_printf(m, ":count=%ld\n", count);
304
305         return 0;
306 }
307
308 static int
309 ftrace_trace_onoff_unreg(char *glob, char *cmd, char *param)
310 {
311         struct ftrace_probe_ops *ops;
312
313         /* we register both traceon and traceoff to this callback */
314         if (strcmp(cmd, "traceon") == 0)
315                 ops = &traceon_probe_ops;
316         else
317                 ops = &traceoff_probe_ops;
318
319         unregister_ftrace_function_probe_func(glob, ops);
320
321         return 0;
322 }
323
324 static int
325 ftrace_trace_onoff_callback(char *glob, char *cmd, char *param, int enable)
326 {
327         struct ftrace_probe_ops *ops;
328         void *count = (void *)-1;
329         char *number;
330         int ret;
331
332         /* hash funcs only work with set_ftrace_filter */
333         if (!enable)
334                 return -EINVAL;
335
336         if (glob[0] == '!')
337                 return ftrace_trace_onoff_unreg(glob+1, cmd, param);
338
339         /* we register both traceon and traceoff to this callback */
340         if (strcmp(cmd, "traceon") == 0)
341                 ops = &traceon_probe_ops;
342         else
343                 ops = &traceoff_probe_ops;
344
345         if (!param)
346                 goto out_reg;
347
348         number = strsep(&param, ":");
349
350         if (!strlen(number))
351                 goto out_reg;
352
353         /*
354          * We use the callback data field (which is a pointer)
355          * as our counter.
356          */
357         ret = strict_strtoul(number, 0, (unsigned long *)&count);
358         if (ret)
359                 return ret;
360
361  out_reg:
362         ret = register_ftrace_function_probe(glob, ops, count);
363
364         return ret < 0 ? ret : 0;
365 }
366
367 static struct ftrace_func_command ftrace_traceon_cmd = {
368         .name                   = "traceon",
369         .func                   = ftrace_trace_onoff_callback,
370 };
371
372 static struct ftrace_func_command ftrace_traceoff_cmd = {
373         .name                   = "traceoff",
374         .func                   = ftrace_trace_onoff_callback,
375 };
376
377 static int __init init_func_cmd_traceon(void)
378 {
379         int ret;
380
381         ret = register_ftrace_command(&ftrace_traceoff_cmd);
382         if (ret)
383                 return ret;
384
385         ret = register_ftrace_command(&ftrace_traceon_cmd);
386         if (ret)
387                 unregister_ftrace_command(&ftrace_traceoff_cmd);
388         return ret;
389 }
390 #else
391 static inline int init_func_cmd_traceon(void)
392 {
393         return 0;
394 }
395 #endif /* CONFIG_DYNAMIC_FTRACE */
396
397 static __init int init_function_trace(void)
398 {
399         init_func_cmd_traceon();
400         return register_tracer(&function_trace);
401 }
402 device_initcall(init_function_trace);
403