1 // SPDX-License-Identifier: GPL-2.0
5 * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
7 #include <linux/kallsyms.h>
8 #include <linux/seq_file.h>
9 #include <linux/spinlock.h>
10 #include <linux/irqflags.h>
11 #include <linux/uaccess.h>
12 #include <linux/module.h>
13 #include <linux/ftrace.h>
14 #include <linux/hash.h>
16 #include <asm/local.h>
19 #include "trace_stat.h"
20 #include "trace_output.h"
22 #ifdef CONFIG_BRANCH_TRACER
24 static struct tracer branch_trace;
25 static int branch_tracing_enabled __read_mostly;
26 static DEFINE_MUTEX(branch_tracing_mutex);
28 static struct trace_array *branch_tracer;
31 probe_likely_condition(struct ftrace_likely_data *f, int val, int expect)
33 struct trace_event_call *call = &event_branch;
34 struct trace_array *tr = branch_tracer;
35 struct trace_buffer *buffer;
36 struct trace_array_cpu *data;
37 struct ring_buffer_event *event;
38 struct trace_branch *entry;
40 unsigned int trace_ctx;
43 if (current->trace_recursion & TRACE_BRANCH_BIT)
47 * I would love to save just the ftrace_likely_data pointer, but
48 * this code can also be used by modules. Ugly things can happen
49 * if the module is unloaded, and then we go and read the
50 * pointer. This is slower, but much safer.
56 raw_local_irq_save(flags);
57 current->trace_recursion |= TRACE_BRANCH_BIT;
58 data = this_cpu_ptr(tr->array_buffer.data);
59 if (atomic_read(&data->disabled))
62 trace_ctx = tracing_gen_ctx_flags(flags);
63 buffer = tr->array_buffer.buffer;
64 event = trace_buffer_lock_reserve(buffer, TRACE_BRANCH,
65 sizeof(*entry), trace_ctx);
69 entry = ring_buffer_event_data(event);
71 /* Strip off the path, only save the file */
72 p = f->data.file + strlen(f->data.file);
73 while (p >= f->data.file && *p != '/')
77 strncpy(entry->func, f->data.func, TRACE_FUNC_SIZE);
78 strncpy(entry->file, p, TRACE_FILE_SIZE);
79 entry->func[TRACE_FUNC_SIZE] = 0;
80 entry->file[TRACE_FILE_SIZE] = 0;
81 entry->constant = f->constant;
82 entry->line = f->data.line;
83 entry->correct = val == expect;
85 if (!call_filter_check_discard(call, entry, buffer, event))
86 trace_buffer_unlock_commit_nostack(buffer, event);
89 current->trace_recursion &= ~TRACE_BRANCH_BIT;
90 raw_local_irq_restore(flags);
94 void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)
96 if (!branch_tracing_enabled)
99 probe_likely_condition(f, val, expect);
102 int enable_branch_tracing(struct trace_array *tr)
104 mutex_lock(&branch_tracing_mutex);
107 * Must be seen before enabling. The reader is a condition
108 * where we do not need a matching rmb()
111 branch_tracing_enabled++;
112 mutex_unlock(&branch_tracing_mutex);
117 void disable_branch_tracing(void)
119 mutex_lock(&branch_tracing_mutex);
121 if (!branch_tracing_enabled)
124 branch_tracing_enabled--;
127 mutex_unlock(&branch_tracing_mutex);
130 static int branch_trace_init(struct trace_array *tr)
132 return enable_branch_tracing(tr);
135 static void branch_trace_reset(struct trace_array *tr)
137 disable_branch_tracing();
140 static enum print_line_t trace_branch_print(struct trace_iterator *iter,
141 int flags, struct trace_event *event)
143 struct trace_branch *field;
145 trace_assign_type(field, iter->ent);
147 trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n",
148 field->correct ? " ok " : " MISS ",
153 return trace_handle_return(&iter->seq);
156 static void branch_print_header(struct seq_file *s)
158 seq_puts(s, "# TASK-PID CPU# TIMESTAMP CORRECT"
164 static struct trace_event_functions trace_branch_funcs = {
165 .trace = trace_branch_print,
168 static struct trace_event trace_branch_event = {
169 .type = TRACE_BRANCH,
170 .funcs = &trace_branch_funcs,
173 static struct tracer branch_trace __read_mostly =
176 .init = branch_trace_init,
177 .reset = branch_trace_reset,
178 #ifdef CONFIG_FTRACE_SELFTEST
179 .selftest = trace_selftest_startup_branch,
180 #endif /* CONFIG_FTRACE_SELFTEST */
181 .print_header = branch_print_header,
184 __init static int init_branch_tracer(void)
188 ret = register_trace_event(&trace_branch_event);
190 printk(KERN_WARNING "Warning: could not register "
194 return register_tracer(&branch_trace);
196 core_initcall(init_branch_tracer);
200 void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)
203 #endif /* CONFIG_BRANCH_TRACER */
205 void ftrace_likely_update(struct ftrace_likely_data *f, int val,
206 int expect, int is_constant)
208 unsigned long flags = user_access_save();
210 /* A constant is always correct */
216 * I would love to have a trace point here instead, but the
217 * trace point code is so inundated with unlikely and likely
218 * conditions that the recursive nightmare that exists is too
219 * much to try to get working. At least for now.
221 trace_likely_condition(f, val, expect);
223 /* FIXME: Make this atomic! */
229 user_access_restore(flags);
231 EXPORT_SYMBOL(ftrace_likely_update);
233 extern unsigned long __start_annotated_branch_profile[];
234 extern unsigned long __stop_annotated_branch_profile[];
236 static int annotated_branch_stat_headers(struct seq_file *m)
238 seq_puts(m, " correct incorrect % "
241 " ------- --------- - "
247 static inline long get_incorrect_percent(const struct ftrace_branch_data *p)
252 percent = p->incorrect * 100;
253 percent /= p->correct + p->incorrect;
255 percent = p->incorrect ? 100 : -1;
260 static const char *branch_stat_process_file(struct ftrace_branch_data *p)
264 /* Only print the file, not the path */
265 f = p->file + strlen(p->file);
266 while (f >= p->file && *f != '/')
271 static void branch_stat_show(struct seq_file *m,
272 struct ftrace_branch_data *p, const char *f)
277 * The miss is overlayed on correct, and hit on incorrect.
279 percent = get_incorrect_percent(p);
284 seq_printf(m, "%3ld ", percent);
286 seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line);
289 static int branch_stat_show_normal(struct seq_file *m,
290 struct ftrace_branch_data *p, const char *f)
292 seq_printf(m, "%8lu %8lu ", p->correct, p->incorrect);
293 branch_stat_show(m, p, f);
297 static int annotate_branch_stat_show(struct seq_file *m, void *v)
299 struct ftrace_likely_data *p = v;
303 f = branch_stat_process_file(&p->data);
306 return branch_stat_show_normal(m, &p->data, f);
308 l = snprintf(NULL, 0, "/%lu", p->constant);
309 l = l > 8 ? 0 : 8 - l;
311 seq_printf(m, "%8lu/%lu %*lu ",
312 p->data.correct, p->constant, l, p->data.incorrect);
313 branch_stat_show(m, &p->data, f);
317 static void *annotated_branch_stat_start(struct tracer_stat *trace)
319 return __start_annotated_branch_profile;
323 annotated_branch_stat_next(void *v, int idx)
325 struct ftrace_likely_data *p = v;
329 if ((void *)p >= (void *)__stop_annotated_branch_profile)
335 static int annotated_branch_stat_cmp(const void *p1, const void *p2)
337 const struct ftrace_branch_data *a = p1;
338 const struct ftrace_branch_data *b = p2;
340 long percent_a, percent_b;
342 percent_a = get_incorrect_percent(a);
343 percent_b = get_incorrect_percent(b);
345 if (percent_a < percent_b)
347 if (percent_a > percent_b)
350 if (a->incorrect < b->incorrect)
352 if (a->incorrect > b->incorrect)
356 * Since the above shows worse (incorrect) cases
357 * first, we continue that by showing best (correct)
360 if (a->correct > b->correct)
362 if (a->correct < b->correct)
368 static struct tracer_stat annotated_branch_stats = {
369 .name = "branch_annotated",
370 .stat_start = annotated_branch_stat_start,
371 .stat_next = annotated_branch_stat_next,
372 .stat_cmp = annotated_branch_stat_cmp,
373 .stat_headers = annotated_branch_stat_headers,
374 .stat_show = annotate_branch_stat_show
377 __init static int init_annotated_branch_stats(void)
381 ret = register_stat_tracer(&annotated_branch_stats);
383 printk(KERN_WARNING "Warning: could not register "
384 "annotated branches stats\n");
389 fs_initcall(init_annotated_branch_stats);
391 #ifdef CONFIG_PROFILE_ALL_BRANCHES
393 extern unsigned long __start_branch_profile[];
394 extern unsigned long __stop_branch_profile[];
396 static int all_branch_stat_headers(struct seq_file *m)
398 seq_puts(m, " miss hit % "
401 " ------- --------- - "
407 static void *all_branch_stat_start(struct tracer_stat *trace)
409 return __start_branch_profile;
413 all_branch_stat_next(void *v, int idx)
415 struct ftrace_branch_data *p = v;
419 if ((void *)p >= (void *)__stop_branch_profile)
425 static int all_branch_stat_show(struct seq_file *m, void *v)
427 struct ftrace_branch_data *p = v;
430 f = branch_stat_process_file(p);
431 return branch_stat_show_normal(m, p, f);
434 static struct tracer_stat all_branch_stats = {
435 .name = "branch_all",
436 .stat_start = all_branch_stat_start,
437 .stat_next = all_branch_stat_next,
438 .stat_headers = all_branch_stat_headers,
439 .stat_show = all_branch_stat_show
442 __init static int all_annotated_branch_stats(void)
446 ret = register_stat_tracer(&all_branch_stats);
448 printk(KERN_WARNING "Warning: could not register "
449 "all branches stats\n");
454 fs_initcall(all_annotated_branch_stats);
455 #endif /* CONFIG_PROFILE_ALL_BRANCHES */