diff options
Diffstat (limited to 'kernel/trace/trace_boot.c')
| -rw-r--r-- | kernel/trace/trace_boot.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c new file mode 100644 index 00000000000..3ccebde2848 --- /dev/null +++ b/kernel/trace/trace_boot.c @@ -0,0 +1,186 @@ +/* + * 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 bool pre_initcalls_finished; + +/* Tells the boot tracer that the pre_smp_initcalls are finished. + * So we are ready . + * It doesn't enable sched events tracing however. + * You have to call enable_boot_trace to do so. + */ +void start_boot_trace(void) +{ + pre_initcalls_finished = true; +} + +void enable_boot_trace(void) +{ + if (pre_initcalls_finished) + tracing_start_sched_switch_record(); +} + +void disable_boot_trace(void) +{ + if (pre_initcalls_finished) + tracing_stop_sched_switch_record(); +} + +static int boot_trace_init(struct trace_array *tr) +{ + int cpu; + boot_trace = tr; + + for_each_cpu_mask(cpu, cpu_possible_map) + tracing_reset(tr, cpu); + + tracing_sched_switch_assign_trace(tr); + return 0; +} + +static enum print_line_t +initcall_call_print_line(struct trace_iterator *iter) +{ + struct trace_entry *entry = iter->ent; + struct trace_seq *s = &iter->seq; + struct trace_boot_call *field; + struct boot_trace_call *call; + u64 ts; + unsigned long nsec_rem; + int ret; + + trace_assign_type(field, entry); + call = &field->boot_call; + ts = iter->ts; + nsec_rem = do_div(ts, 1000000000); + + ret = trace_seq_printf(s, "[%5ld.%09ld] calling %s @ %i\n", + (unsigned long)ts, nsec_rem, call->func, call->caller); + + if (!ret) + return TRACE_TYPE_PARTIAL_LINE; + else + return TRACE_TYPE_HANDLED; +} + +static enum print_line_t +initcall_ret_print_line(struct trace_iterator *iter) +{ + struct trace_entry *entry = iter->ent; + struct trace_seq *s = &iter->seq; + struct trace_boot_ret *field; + struct boot_trace_ret *init_ret; + u64 ts; + unsigned long nsec_rem; + int ret; + + trace_assign_type(field, entry); + init_ret = &field->boot_ret; + ts = iter->ts; + nsec_rem = do_div(ts, 1000000000); + + ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s " + "returned %d after %llu msecs\n", + (unsigned long) ts, + nsec_rem, + init_ret->func, init_ret->result, init_ret->duration); + + if (!ret) + return TRACE_TYPE_PARTIAL_LINE; + else + return TRACE_TYPE_HANDLED; +} + +static enum print_line_t initcall_print_line(struct trace_iterator *iter) +{ + struct trace_entry *entry = iter->ent; + + switch (entry->type) { + case TRACE_BOOT_CALL: + return initcall_call_print_line(iter); + case TRACE_BOOT_RET: + return initcall_ret_print_line(iter); + default: + return TRACE_TYPE_UNHANDLED; + } +} + +struct tracer boot_tracer __read_mostly = +{ + .name = "initcall", + .init = boot_trace_init, + .reset = tracing_reset_online_cpus, + .print_line = initcall_print_line, +}; + +void trace_boot_call(struct boot_trace_call *bt, initcall_t fn) +{ + struct ring_buffer_event *event; + struct trace_boot_call *entry; + unsigned long irq_flags; + struct trace_array *tr = boot_trace; + + if (!pre_initcalls_finished) + return; + + /* Get its name now since this function could + * disappear because it is in the .init section. + */ + sprint_symbol(bt->func, (unsigned long)fn); + preempt_disable(); + + 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_CALL; + entry->boot_call = *bt; + ring_buffer_unlock_commit(tr->buffer, event, irq_flags); + + trace_wake_up(); + + out: + preempt_enable(); +} + +void trace_boot_ret(struct boot_trace_ret *bt, initcall_t fn) +{ + struct ring_buffer_event *event; + struct trace_boot_ret *entry; + unsigned long irq_flags; + struct trace_array *tr = boot_trace; + + if (!pre_initcalls_finished) + return; + + sprint_symbol(bt->func, (unsigned long)fn); + preempt_disable(); + + 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_RET; + entry->boot_ret = *bt; + ring_buffer_unlock_commit(tr->buffer, event, irq_flags); + + trace_wake_up(); + + out: + preempt_enable(); +} |