git.oblomov.eu Git - linux-2.6/blob - 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 bool pre_initcalls_finished;
  17
  18 /* Tells the boot tracer that the pre_smp_initcalls are finished.
  19  * So we are ready .
  20  * It doesn't enable sched events tracing however.
  21  * You have to call enable_boot_trace to do so.
  22  */
  23 void start_boot_trace(void)
  24 {
  25         pre_initcalls_finished = true;
  26 }
  27
  28 void enable_boot_trace(void)
  29 {
  30         if (pre_initcalls_finished)
  31                 tracing_start_sched_switch_record();
  32 }
  33
  34 void disable_boot_trace(void)
  35 {
  36         if (pre_initcalls_finished)
  37                 tracing_stop_sched_switch_record();
  38 }
  39
  40 static void reset_boot_trace(struct trace_array *tr)
  41 {
  42         int cpu;
  43
  44         tr->time_start = ftrace_now(tr->cpu);
  45
  46         for_each_online_cpu(cpu)
  47                 tracing_reset(tr, cpu);
  48 }
  49
  50 static void boot_trace_init(struct trace_array *tr)
  51 {
  52         int cpu;
  53         boot_trace = tr;
  54
  55         for_each_cpu_mask(cpu, cpu_possible_map)
  56                 tracing_reset(tr, cpu);
  57
  58         tracing_sched_switch_assign_trace(tr);
  59 }
  60
  61 static enum print_line_t
  62 initcall_call_print_line(struct trace_iterator *iter)
  63 {
  64         struct trace_entry *entry = iter->ent;
  65         struct trace_seq *s = &iter->seq;
  66         struct trace_boot_call *field;
  67         struct boot_trace_call *call;
  68         u64 ts;
  69         unsigned long nsec_rem;
  70         int ret;
  71
  72         trace_assign_type(field, entry);
  73         call = &field->boot_call;
  74         ts = iter->ts;
  75         nsec_rem = do_div(ts, 1000000000);
  76
  77         ret = trace_seq_printf(s, "[%5ld.%09ld] calling  %s @ %i\n",
  78                         (unsigned long)ts, nsec_rem, call->func, call->caller);
  79
  80         if (!ret)
  81                 return TRACE_TYPE_PARTIAL_LINE;
  82         else
  83                 return TRACE_TYPE_HANDLED;
  84 }
  85
  86 static enum print_line_t
  87 initcall_ret_print_line(struct trace_iterator *iter)
  88 {
  89         struct trace_entry *entry = iter->ent;
  90         struct trace_seq *s = &iter->seq;
  91         struct trace_boot_ret *field;
  92         struct boot_trace_ret *init_ret;
  93         u64 ts;
  94         unsigned long nsec_rem;
  95         int ret;
  96
  97         trace_assign_type(field, entry);
  98         init_ret = &field->boot_ret;
  99         ts = iter->ts;
 100         nsec_rem = do_div(ts, 1000000000);
 101
 102         ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s "
 103                         "returned %d after %llu msecs\n",
 104                         (unsigned long) ts,
 105                         nsec_rem,
 106                         init_ret->func, init_ret->result, init_ret->duration);
 107
 108         if (!ret)
 109                 return TRACE_TYPE_PARTIAL_LINE;
 110         else
 111                 return TRACE_TYPE_HANDLED;
 112 }
 113
 114 static enum print_line_t initcall_print_line(struct trace_iterator *iter)
 115 {
 116         struct trace_entry *entry = iter->ent;
 117
 118         switch (entry->type) {
 119         case TRACE_BOOT_CALL:
 120                 return initcall_call_print_line(iter);
 121         case TRACE_BOOT_RET:
 122                 return initcall_ret_print_line(iter);
 123         default:
 124                 return TRACE_TYPE_UNHANDLED;
 125         }
 126 }
 127
 128 struct tracer boot_tracer __read_mostly =
 129 {
 130         .name           = "initcall",
 131         .init           = boot_trace_init,
 132         .reset          = reset_boot_trace,
 133         .print_line     = initcall_print_line,
 134 };
 135
 136 void trace_boot_call(struct boot_trace_call *bt, initcall_t fn)
 137 {
 138         struct ring_buffer_event *event;
 139         struct trace_boot_call *entry;
 140         unsigned long irq_flags;
 141         struct trace_array *tr = boot_trace;
 142
 143         if (!pre_initcalls_finished)
 144                 return;
 145
 146         /* Get its name now since this function could
 147          * disappear because it is in the .init section.
 148          */
 149         sprint_symbol(bt->func, (unsigned long)fn);
 150         preempt_disable();
 151
 152         event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 153                                          &irq_flags);
 154         if (!event)
 155                 goto out;
 156         entry   = ring_buffer_event_data(event);
 157         tracing_generic_entry_update(&entry->ent, 0, 0);
 158         entry->ent.type = TRACE_BOOT_CALL;
 159         entry->boot_call = *bt;
 160         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 161
 162         trace_wake_up();
 163
 164  out:
 165         preempt_enable();
 166 }
 167
 168 void trace_boot_ret(struct boot_trace_ret *bt, initcall_t fn)
 169 {
 170         struct ring_buffer_event *event;
 171         struct trace_boot_ret *entry;
 172         unsigned long irq_flags;
 173         struct trace_array *tr = boot_trace;
 174
 175         if (!pre_initcalls_finished)
 176                 return;
 177
 178         sprint_symbol(bt->func, (unsigned long)fn);
 179         preempt_disable();
 180
 181         event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 182                                          &irq_flags);
 183         if (!event)
 184                 goto out;
 185         entry   = ring_buffer_event_data(event);
 186         tracing_generic_entry_update(&entry->ent, 0, 0);
 187         entry->ent.type = TRACE_BOOT_RET;
 188         entry->boot_ret = *bt;
 189         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 190
 191         trace_wake_up();
 192
 193  out:
 194         preempt_enable();
 195 }