diff options
Diffstat (limited to 'kernel/trace/trace_boot.c')
-rw-r--r-- | kernel/trace/trace_boot.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c new file mode 100644 index 00000000000..d0a5e50eeff --- /dev/null +++ b/kernel/trace/trace_boot.c @@ -0,0 +1,126 @@ +/* + * ring buffer based initcalls tracer + * + * Copyright (C) 2008 Frederic Weisbecker <fweisbec@gmail.com> + * + */ + +#include <linux/init.h> +#include <linux/debugfs.h> +#include <linux/ftrace.h> +#include <linux/kallsyms.h> + +#include "trace.h" + +static struct trace_array *boot_trace; +static int trace_boot_enabled; + + +/* Should be started after do_pre_smp_initcalls() in init/main.c */ +void start_boot_trace(void) +{ + trace_boot_enabled = 1; +} + +void stop_boot_trace(void) +{ + trace_boot_enabled = 0; +} + +void reset_boot_trace(struct trace_array *tr) +{ + stop_boot_trace(); +} + +static void boot_trace_init(struct trace_array *tr) +{ + int cpu; + boot_trace = tr; + + trace_boot_enabled = 0; + + for_each_cpu_mask(cpu, cpu_possible_map) + tracing_reset(tr, cpu); +} + +static void boot_trace_ctrl_update(struct trace_array *tr) +{ + if (tr->ctrl) + start_boot_trace(); + else + stop_boot_trace(); +} + +static enum print_line_t initcall_print_line(struct trace_iterator *iter) +{ + int ret; + struct trace_entry *entry = iter->ent; + struct trace_boot *field = (struct trace_boot *)entry; + struct boot_trace *it = &field->initcall; + struct trace_seq *s = &iter->seq; + struct timespec calltime = ktime_to_timespec(it->calltime); + struct timespec rettime = ktime_to_timespec(it->rettime); + + if (entry->type == TRACE_BOOT) { + ret = trace_seq_printf(s, "[%5ld.%09ld] calling %s @ %i\n", + calltime.tv_sec, + calltime.tv_nsec, + it->func, it->caller); + if (!ret) + return TRACE_TYPE_PARTIAL_LINE; + + ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s " + "returned %d after %lld msecs\n", + rettime.tv_sec, + rettime.tv_nsec, + it->func, it->result, it->duration); + + if (!ret) + return TRACE_TYPE_PARTIAL_LINE; + return TRACE_TYPE_HANDLED; + } + return TRACE_TYPE_UNHANDLED; +} + +struct tracer boot_tracer __read_mostly = +{ + .name = "initcall", + .init = boot_trace_init, + .reset = reset_boot_trace, + .ctrl_update = boot_trace_ctrl_update, + .print_line = initcall_print_line, +}; + +void trace_boot(struct boot_trace *it, initcall_t fn) +{ + struct ring_buffer_event *event; + struct trace_boot *entry; + struct trace_array_cpu *data; + unsigned long irq_flags; + struct trace_array *tr = boot_trace; + + if (!trace_boot_enabled) + return; + + /* Get its name now since this function could + * disappear because it is in the .init section. + */ + sprint_symbol(it->func, (unsigned long)fn); + preempt_disable(); + data = tr->data[smp_processor_id()]; + + event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), + &irq_flags); + if (!event) + goto out; + entry = ring_buffer_event_data(event); + tracing_generic_entry_update(&entry->ent, 0, 0); + entry->ent.type = TRACE_BOOT; + entry->initcall = *it; + ring_buffer_unlock_commit(tr->buffer, event, irq_flags); + + trace_wake_up(); + + out: + preempt_enable(); +} |