/* * 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();}