Merge branch 'linus' into tracing-v28-for-linus-v3
[linux-2.6] / kernel / trace / trace_boot.c
1 /*
2  * ring buffer based initcalls tracer
3  *
4  * Copyright (C) 2008 Frederic Weisbecker <fweisbec@gmail.com>
5  *
6  */
7
8 #include <linux/init.h>
9 #include <linux/debugfs.h>
10 #include <linux/ftrace.h>
11 #include <linux/kallsyms.h>
12
13 #include "trace.h"
14
15 static struct trace_array *boot_trace;
16 static int trace_boot_enabled;
17
18
19 /* Should be started after do_pre_smp_initcalls() in init/main.c */
20 void start_boot_trace(void)
21 {
22         trace_boot_enabled = 1;
23 }
24
25 void stop_boot_trace(void)
26 {
27         trace_boot_enabled = 0;
28 }
29
30 void reset_boot_trace(struct trace_array *tr)
31 {
32         stop_boot_trace();
33 }
34
35 static void boot_trace_init(struct trace_array *tr)
36 {
37         int cpu;
38         boot_trace = tr;
39
40         trace_boot_enabled = 0;
41
42         for_each_cpu_mask(cpu, cpu_possible_map)
43                 tracing_reset(tr, cpu);
44 }
45
46 static void boot_trace_ctrl_update(struct trace_array *tr)
47 {
48         if (tr->ctrl)
49                 start_boot_trace();
50         else
51                 stop_boot_trace();
52 }
53
54 static enum print_line_t initcall_print_line(struct trace_iterator *iter)
55 {
56         int ret;
57         struct trace_entry *entry = iter->ent;
58         struct trace_boot *field = (struct trace_boot *)entry;
59         struct boot_trace *it = &field->initcall;
60         struct trace_seq *s = &iter->seq;
61         struct timespec calltime = ktime_to_timespec(it->calltime);
62         struct timespec rettime = ktime_to_timespec(it->rettime);
63
64         if (entry->type == TRACE_BOOT) {
65                 ret = trace_seq_printf(s, "[%5ld.%09ld] calling  %s @ %i\n",
66                                           calltime.tv_sec,
67                                           calltime.tv_nsec,
68                                           it->func, it->caller);
69                 if (!ret)
70                         return TRACE_TYPE_PARTIAL_LINE;
71
72                 ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s "
73                                           "returned %d after %lld msecs\n",
74                                           rettime.tv_sec,
75                                           rettime.tv_nsec,
76                                           it->func, it->result, it->duration);
77
78                 if (!ret)
79                         return TRACE_TYPE_PARTIAL_LINE;
80                 return TRACE_TYPE_HANDLED;
81         }
82         return TRACE_TYPE_UNHANDLED;
83 }
84
85 struct tracer boot_tracer __read_mostly =
86 {
87         .name           = "initcall",
88         .init           = boot_trace_init,
89         .reset          = reset_boot_trace,
90         .ctrl_update    = boot_trace_ctrl_update,
91         .print_line     = initcall_print_line,
92 };
93
94 void trace_boot(struct boot_trace *it, initcall_t fn)
95 {
96         struct ring_buffer_event *event;
97         struct trace_boot *entry;
98         struct trace_array_cpu *data;
99         unsigned long irq_flags;
100         struct trace_array *tr = boot_trace;
101
102         if (!trace_boot_enabled)
103                 return;
104
105         /* Get its name now since this function could
106          * disappear because it is in the .init section.
107          */
108         sprint_symbol(it->func, (unsigned long)fn);
109         preempt_disable();
110         data = tr->data[smp_processor_id()];
111
112         event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
113                                          &irq_flags);
114         if (!event)
115                 goto out;
116         entry   = ring_buffer_event_data(event);
117         tracing_generic_entry_update(&entry->ent, 0, 0);
118         entry->ent.type = TRACE_BOOT;
119         entry->initcall = *it;
120         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
121
122         trace_wake_up();
123
124  out:
125         preempt_enable();
126 }