2 * ring buffer based initcalls tracer
4 * Copyright (C) 2008 Frederic Weisbecker <fweisbec@gmail.com>
8 #include <linux/init.h>
9 #include <linux/debugfs.h>
10 #include <linux/ftrace.h>
11 #include <linux/kallsyms.h>
15 static struct trace_array *boot_trace;
16 static bool pre_initcalls_finished;
18 /* Tells the boot tracer that the pre_smp_initcalls are finished.
20 * It doesn't enable sched events tracing however.
21 * You have to call enable_boot_trace to do so.
23 void start_boot_trace(void)
25 pre_initcalls_finished = true;
28 void enable_boot_trace(void)
30 if (pre_initcalls_finished)
31 tracing_start_sched_switch_record();
34 void disable_boot_trace(void)
36 if (pre_initcalls_finished)
37 tracing_stop_sched_switch_record();
40 static void reset_boot_trace(struct trace_array *tr)
44 tr->time_start = ftrace_now(tr->cpu);
46 for_each_online_cpu(cpu)
47 tracing_reset(tr, cpu);
50 static void boot_trace_init(struct trace_array *tr)
55 for_each_cpu_mask(cpu, cpu_possible_map)
56 tracing_reset(tr, cpu);
58 tracing_sched_switch_assign_trace(tr);
61 static void boot_trace_ctrl_update(struct trace_array *tr)
69 static enum print_line_t initcall_print_line(struct trace_iterator *iter)
72 struct trace_entry *entry = iter->ent;
73 struct trace_boot *field = (struct trace_boot *)entry;
74 struct boot_trace *it = &field->initcall;
75 struct trace_seq *s = &iter->seq;
76 struct timespec calltime = ktime_to_timespec(it->calltime);
77 struct timespec rettime = ktime_to_timespec(it->rettime);
79 if (entry->type == TRACE_BOOT) {
80 ret = trace_seq_printf(s, "[%5ld.%09ld] calling %s @ %i\n",
83 it->func, it->caller);
85 return TRACE_TYPE_PARTIAL_LINE;
87 ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s "
88 "returned %d after %lld msecs\n",
91 it->func, it->result, it->duration);
94 return TRACE_TYPE_PARTIAL_LINE;
95 return TRACE_TYPE_HANDLED;
97 return TRACE_TYPE_UNHANDLED;
100 struct tracer boot_tracer __read_mostly =
103 .init = boot_trace_init,
104 .reset = reset_boot_trace,
105 .ctrl_update = boot_trace_ctrl_update,
106 .print_line = initcall_print_line,
109 void trace_boot(struct boot_trace *it, initcall_t fn)
111 struct ring_buffer_event *event;
112 struct trace_boot *entry;
113 struct trace_array_cpu *data;
114 unsigned long irq_flags;
115 struct trace_array *tr = boot_trace;
117 if (!pre_initcalls_finished)
120 /* Get its name now since this function could
121 * disappear because it is in the .init section.
123 sprint_symbol(it->func, (unsigned long)fn);
125 data = tr->data[smp_processor_id()];
127 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
131 entry = ring_buffer_event_data(event);
132 tracing_generic_entry_update(&entry->ent, 0, 0);
133 entry->ent.type = TRACE_BOOT;
134 entry->initcall = *it;
135 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);