tracing: Introduce trace_buffer_{lock_reserve,unlock_commit}
[linux-2.6.git] / 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 #include "trace_output.h"
15
16 static struct trace_array *boot_trace;
17 static bool pre_initcalls_finished;
18
19 /* Tells the boot tracer that the pre_smp_initcalls are finished.
20  * So we are ready .
21  * It doesn't enable sched events tracing however.
22  * You have to call enable_boot_trace to do so.
23  */
24 void start_boot_trace(void)
25 {
26         pre_initcalls_finished = true;
27 }
28
29 void enable_boot_trace(void)
30 {
31         if (boot_trace && pre_initcalls_finished)
32                 tracing_start_sched_switch_record();
33 }
34
35 void disable_boot_trace(void)
36 {
37         if (boot_trace && pre_initcalls_finished)
38                 tracing_stop_sched_switch_record();
39 }
40
41 static int boot_trace_init(struct trace_array *tr)
42 {
43         int cpu;
44         boot_trace = tr;
45
46         if (!tr)
47                 return 0;
48
49         for_each_cpu(cpu, cpu_possible_mask)
50                 tracing_reset(tr, cpu);
51
52         tracing_sched_switch_assign_trace(tr);
53         return 0;
54 }
55
56 static enum print_line_t
57 initcall_call_print_line(struct trace_iterator *iter)
58 {
59         struct trace_entry *entry = iter->ent;
60         struct trace_seq *s = &iter->seq;
61         struct trace_boot_call *field;
62         struct boot_trace_call *call;
63         u64 ts;
64         unsigned long nsec_rem;
65         int ret;
66
67         trace_assign_type(field, entry);
68         call = &field->boot_call;
69         ts = iter->ts;
70         nsec_rem = do_div(ts, 1000000000);
71
72         ret = trace_seq_printf(s, "[%5ld.%09ld] calling  %s @ %i\n",
73                         (unsigned long)ts, nsec_rem, call->func, call->caller);
74
75         if (!ret)
76                 return TRACE_TYPE_PARTIAL_LINE;
77         else
78                 return TRACE_TYPE_HANDLED;
79 }
80
81 static enum print_line_t
82 initcall_ret_print_line(struct trace_iterator *iter)
83 {
84         struct trace_entry *entry = iter->ent;
85         struct trace_seq *s = &iter->seq;
86         struct trace_boot_ret *field;
87         struct boot_trace_ret *init_ret;
88         u64 ts;
89         unsigned long nsec_rem;
90         int ret;
91
92         trace_assign_type(field, entry);
93         init_ret = &field->boot_ret;
94         ts = iter->ts;
95         nsec_rem = do_div(ts, 1000000000);
96
97         ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s "
98                         "returned %d after %llu msecs\n",
99                         (unsigned long) ts,
100                         nsec_rem,
101                         init_ret->func, init_ret->result, init_ret->duration);
102
103         if (!ret)
104                 return TRACE_TYPE_PARTIAL_LINE;
105         else
106                 return TRACE_TYPE_HANDLED;
107 }
108
109 static enum print_line_t initcall_print_line(struct trace_iterator *iter)
110 {
111         struct trace_entry *entry = iter->ent;
112
113         switch (entry->type) {
114         case TRACE_BOOT_CALL:
115                 return initcall_call_print_line(iter);
116         case TRACE_BOOT_RET:
117                 return initcall_ret_print_line(iter);
118         default:
119                 return TRACE_TYPE_UNHANDLED;
120         }
121 }
122
123 struct tracer boot_tracer __read_mostly =
124 {
125         .name           = "initcall",
126         .init           = boot_trace_init,
127         .reset          = tracing_reset_online_cpus,
128         .print_line     = initcall_print_line,
129 };
130
131 void trace_boot_call(struct boot_trace_call *bt, initcall_t fn)
132 {
133         struct ring_buffer_event *event;
134         struct trace_boot_call *entry;
135         struct trace_array *tr = boot_trace;
136
137         if (!tr || !pre_initcalls_finished)
138                 return;
139
140         /* Get its name now since this function could
141          * disappear because it is in the .init section.
142          */
143         sprint_symbol(bt->func, (unsigned long)fn);
144         preempt_disable();
145
146         event = trace_buffer_lock_reserve(tr, TRACE_BOOT_CALL,
147                                           sizeof(*entry), 0, 0);
148         if (!event)
149                 goto out;
150         entry   = ring_buffer_event_data(event);
151         entry->boot_call = *bt;
152         trace_buffer_unlock_commit(tr, event, 0, 0);
153  out:
154         preempt_enable();
155 }
156
157 void trace_boot_ret(struct boot_trace_ret *bt, initcall_t fn)
158 {
159         struct ring_buffer_event *event;
160         struct trace_boot_ret *entry;
161         struct trace_array *tr = boot_trace;
162
163         if (!tr || !pre_initcalls_finished)
164                 return;
165
166         sprint_symbol(bt->func, (unsigned long)fn);
167         preempt_disable();
168
169         event = trace_buffer_lock_reserve(tr, TRACE_BOOT_RET,
170                                           sizeof(*entry), 0, 0);
171         if (!event)
172                 goto out;
173         entry   = ring_buffer_event_data(event);
174         entry->boot_ret = *bt;
175         trace_buffer_unlock_commit(tr, event, 0, 0);
176  out:
177         preempt_enable();
178 }