[deliverable/linux.git] / kernel / trace / trace_hw_branches.c

/*
 * h/w branch tracer for x86 based on bts
 *
 * Copyright (C) 2008 Markus Metzger <markus.t.metzger@gmail.com>
 *
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/debugfs.h>
#include <linux/ftrace.h>
#include <linux/kallsyms.h>

#include <asm/ds.h>

#include "trace.h"


#define SIZEOF_BTS (1 << 13)

static DEFINE_PER_CPU(struct bts_tracer *, tracer);
static DEFINE_PER_CPU(unsigned char[SIZEOF_BTS], buffer);

#define this_tracer per_cpu(tracer, smp_processor_id())
#define this_buffer per_cpu(buffer, smp_processor_id())


static void bts_trace_start_cpu(void *arg)
{
	if (this_tracer)
		ds_release_bts(this_tracer);

	this_tracer =
		ds_request_bts(/* task = */ NULL, this_buffer, SIZEOF_BTS,
			       /* ovfl = */ NULL, /* th = */ (size_t)-1,
			       BTS_KERNEL);
	if (IS_ERR(this_tracer)) {
		this_tracer = NULL;
		return;
	}
}

static void bts_trace_start(struct trace_array *tr)
{
	int cpu;

	tracing_reset_online_cpus(tr);

	for_each_cpu(cpu, cpu_possible_mask)
		smp_call_function_single(cpu, bts_trace_start_cpu, NULL, 1);
}

static void bts_trace_stop_cpu(void *arg)
{
	if (this_tracer) {
		ds_release_bts(this_tracer);
		this_tracer = NULL;
	}
}

static void bts_trace_stop(struct trace_array *tr)
{
	int cpu;

	for_each_cpu(cpu, cpu_possible_mask)
		smp_call_function_single(cpu, bts_trace_stop_cpu, NULL, 1);
}

static int bts_trace_init(struct trace_array *tr)
{
	tracing_reset_online_cpus(tr);
	bts_trace_start(tr);

	return 0;
}

static void bts_trace_print_header(struct seq_file *m)
{
	seq_puts(m,
		 "# CPU#        FROM                   TO         FUNCTION\n");
	seq_puts(m,
		 "#  |           |                     |             |\n");
}

static enum print_line_t bts_trace_print_line(struct trace_iterator *iter)
{
	struct trace_entry *entry = iter->ent;
	struct trace_seq *seq = &iter->seq;
	struct hw_branch_entry *it;

	trace_assign_type(it, entry);

	if (entry->type == TRACE_HW_BRANCHES) {
		if (trace_seq_printf(seq, "%4d  ", entry->cpu) &&
		    trace_seq_printf(seq, "0x%016llx -> 0x%016llx ",
				     it->from, it->to) &&
		    (!it->from ||
		     seq_print_ip_sym(seq, it->from, /* sym_flags = */ 0)) &&
		    trace_seq_printf(seq, "\n"))
			return TRACE_TYPE_HANDLED;
		return TRACE_TYPE_PARTIAL_LINE;;
	}
	return TRACE_TYPE_UNHANDLED;
}

void trace_hw_branch(struct trace_array *tr, u64 from, u64 to)
{
	struct ring_buffer_event *event;
	struct hw_branch_entry *entry;
	unsigned long irq;

	event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), &irq);
	if (!event)
		return;
	entry	= ring_buffer_event_data(event);
	tracing_generic_entry_update(&entry->ent, 0, from);
	entry->ent.type = TRACE_HW_BRANCHES;
	entry->ent.cpu = smp_processor_id();
	entry->from = from;
	entry->to   = to;
	ring_buffer_unlock_commit(tr->buffer, event, irq);
}

static void trace_bts_at(struct trace_array *tr,
			 const struct bts_trace *trace, void *at)
{
	struct bts_struct bts;
	int err = 0;

	WARN_ON_ONCE(!trace->read);
	if (!trace->read)
		return;

	err = trace->read(this_tracer, at, &bts);
	if (err < 0)
		return;

	switch (bts.qualifier) {
	case BTS_BRANCH:
		trace_hw_branch(tr, bts.variant.lbr.from, bts.variant.lbr.to);
		break;
	}
}

static void trace_bts_cpu(void *arg)
{
	struct trace_array *tr = (struct trace_array *) arg;
	const struct bts_trace *trace;
	unsigned char *at;

	if (!this_tracer)
		return;

	ds_suspend_bts(this_tracer);
	trace = ds_read_bts(this_tracer);
	if (!trace)
		goto out;

	for (at = trace->ds.top; (void *)at < trace->ds.end;
	     at += trace->ds.size)
		trace_bts_at(tr, trace, at);

	for (at = trace->ds.begin; (void *)at < trace->ds.top;
	     at += trace->ds.size)
		trace_bts_at(tr, trace, at);

out:
	ds_resume_bts(this_tracer);
}

static void trace_bts_prepare(struct trace_iterator *iter)
{
	int cpu;

	for_each_cpu(cpu, cpu_possible_mask)
		smp_call_function_single(cpu, trace_bts_cpu, iter->tr, 1);
}

struct tracer bts_tracer __read_mostly =
{
	.name		= "hw-branch-tracer",
	.init		= bts_trace_init,
	.reset		= bts_trace_stop,
	.print_header	= bts_trace_print_header,
	.print_line	= bts_trace_print_line,
	.start		= bts_trace_start,
	.stop		= bts_trace_stop,
	.open		= trace_bts_prepare
};

__init static int init_bts_trace(void)
{
	return register_tracer(&bts_tracer);
}
device_initcall(init_bts_trace);
Commit	Line	Data
1e9b51c2	1	/*
a93751ca	2	* h/w branch tracer for x86 based on bts
1e9b51c2 MM	3	*
	4	* Copyright (C) 2008 Markus Metzger <markus.t.metzger@gmail.com>
	5	*
	6	*/
	7
	8	#include <linux/module.h>
	9	#include <linux/fs.h>
	10	#include <linux/debugfs.h>
	11	#include <linux/ftrace.h>
	12	#include <linux/kallsyms.h>
	13
	14	#include <asm/ds.h>
	15
	16	#include "trace.h"
	17
	18
	19	#define SIZEOF_BTS (1 << 13)
	20
	21	static DEFINE_PER_CPU(struct bts_tracer *, tracer);
	22	static DEFINE_PER_CPU(unsigned char[SIZEOF_BTS], buffer);
	23
	24	#define this_tracer per_cpu(tracer, smp_processor_id())
	25	#define this_buffer per_cpu(buffer, smp_processor_id())
	26
	27
1e9b51c2 MM	28	static void bts_trace_start_cpu(void *arg)
1e9b51c2 MM	29	{
a93751ca MM	30	if (this_tracer)
	31	ds_release_bts(this_tracer);
	32
1e9b51c2 MM	33	this_tracer =
1e9b51c2 MM	34	ds_request_bts(/* task = */ NULL, this_buffer, SIZEOF_BTS,
a93751ca MM	35	/* ovfl = / NULL, / th = */ (size_t)-1,
a93751ca MM	36	BTS_KERNEL);
1e9b51c2 MM	37	if (IS_ERR(this_tracer)) {
	38	this_tracer = NULL;
	39	return;
	40	}
1e9b51c2 MM	41	}
	42
	43	static void bts_trace_start(struct trace_array *tr)
	44	{
	45	int cpu;
	46
213cc060	47	tracing_reset_online_cpus(tr);
1e9b51c2	48
4462344e	49	for_each_cpu(cpu, cpu_possible_mask)
1e9b51c2 MM	50	smp_call_function_single(cpu, bts_trace_start_cpu, NULL, 1);
	51	}
	52
	53	static void bts_trace_stop_cpu(void *arg)
	54	{
	55	if (this_tracer) {
1e9b51c2 MM	56	ds_release_bts(this_tracer);
	57	this_tracer = NULL;
	58	}
	59	}
	60
	61	static void bts_trace_stop(struct trace_array *tr)
	62	{
	63	int cpu;
	64
4462344e	65	for_each_cpu(cpu, cpu_possible_mask)
1e9b51c2 MM	66	smp_call_function_single(cpu, bts_trace_stop_cpu, NULL, 1);
	67	}
	68
	69	static int bts_trace_init(struct trace_array *tr)
	70	{
213cc060	71	tracing_reset_online_cpus(tr);
1e9b51c2 MM	72	bts_trace_start(tr);
	73
	74	return 0;
	75	}
	76
	77	static void bts_trace_print_header(struct seq_file *m)
	78	{
1e9b51c2 MM	79	seq_puts(m,
	80	"# CPU# FROM TO FUNCTION\n");
	81	seq_puts(m,
	82	"# \| \| \| \|\n");
1e9b51c2 MM	83	}
	84
	85	static enum print_line_t bts_trace_print_line(struct trace_iterator *iter)
	86	{
	87	struct trace_entry *entry = iter->ent;
	88	struct trace_seq *seq = &iter->seq;
a93751ca	89	struct hw_branch_entry *it;
1e9b51c2 MM	90
	91	trace_assign_type(it, entry);
	92
a93751ca MM	93	if (entry->type == TRACE_HW_BRANCHES) {
	94	if (trace_seq_printf(seq, "%4d ", entry->cpu) &&
	95	trace_seq_printf(seq, "0x%016llx -> 0x%016llx ",
	96	it->from, it->to) &&
	97	(!it->from \|\|
	98	seq_print_ip_sym(seq, it->from, /* sym_flags = */ 0)) &&
	99	trace_seq_printf(seq, "\n"))
	100	return TRACE_TYPE_HANDLED;
	101	return TRACE_TYPE_PARTIAL_LINE;;
1e9b51c2 MM	102	}
	103	return TRACE_TYPE_UNHANDLED;
	104	}
	105
a93751ca	106	void trace_hw_branch(struct trace_array *tr, u64 from, u64 to)
1e9b51c2 MM	107	{
1e9b51c2 MM	108	struct ring_buffer_event *event;
a93751ca	109	struct hw_branch_entry *entry;
1e9b51c2 MM	110	unsigned long irq;
	111
	112	event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), &irq);
	113	if (!event)
	114	return;
	115	entry = ring_buffer_event_data(event);
	116	tracing_generic_entry_update(&entry->ent, 0, from);
a93751ca	117	entry->ent.type = TRACE_HW_BRANCHES;
1e9b51c2 MM	118	entry->ent.cpu = smp_processor_id();
	119	entry->from = from;
	120	entry->to = to;
	121	ring_buffer_unlock_commit(tr->buffer, event, irq);
	122	}
	123
a93751ca MM	124	static void trace_bts_at(struct trace_array *tr,
a93751ca MM	125	const struct bts_trace trace, void at)
1e9b51c2	126	{
a93751ca MM	127	struct bts_struct bts;
a93751ca MM	128	int err = 0;
1e9b51c2	129
a93751ca MM	130	WARN_ON_ONCE(!trace->read);
a93751ca MM	131	if (!trace->read)
1e9b51c2 MM	132	return;
1e9b51c2 MM	133
a93751ca MM	134	err = trace->read(this_tracer, at, &bts);
	135	if (err < 0)
	136	return;
1e9b51c2	137
a93751ca MM	138	switch (bts.qualifier) {
	139	case BTS_BRANCH:
	140	trace_hw_branch(tr, bts.variant.lbr.from, bts.variant.lbr.to);
	141	break;
	142	}
1e9b51c2 MM	143	}
	144
	145	static void trace_bts_cpu(void *arg)
	146	{
	147	struct trace_array tr = (struct trace_array ) arg;
a93751ca MM	148	const struct bts_trace *trace;
a93751ca MM	149	unsigned char *at;
1e9b51c2 MM	150
	151	if (!this_tracer)
	152	return;
	153
a93751ca MM	154	ds_suspend_bts(this_tracer);
	155	trace = ds_read_bts(this_tracer);
	156	if (!trace)
1e9b51c2 MM	157	goto out;
1e9b51c2 MM	158
a93751ca MM	159	for (at = trace->ds.top; (void *)at < trace->ds.end;
	160	at += trace->ds.size)
	161	trace_bts_at(tr, trace, at);
1e9b51c2	162
a93751ca MM	163	for (at = trace->ds.begin; (void *)at < trace->ds.top;
	164	at += trace->ds.size)
	165	trace_bts_at(tr, trace, at);
1e9b51c2 MM	166
1e9b51c2 MM	167	out:
a93751ca	168	ds_resume_bts(this_tracer);
1e9b51c2 MM	169	}
	170
	171	static void trace_bts_prepare(struct trace_iterator *iter)
	172	{
	173	int cpu;
	174
4462344e	175	for_each_cpu(cpu, cpu_possible_mask)
1e9b51c2 MM	176	smp_call_function_single(cpu, trace_bts_cpu, iter->tr, 1);
	177	}
	178
	179	struct tracer bts_tracer __read_mostly =
	180	{
a93751ca	181	.name = "hw-branch-tracer",
1e9b51c2 MM	182	.init = bts_trace_init,
	183	.reset = bts_trace_stop,
	184	.print_header = bts_trace_print_header,
	185	.print_line = bts_trace_print_line,
	186	.start = bts_trace_start,
	187	.stop = bts_trace_stop,
	188	.open = trace_bts_prepare
	189	};
	190
	191	__init static int init_bts_trace(void)
	192	{
	193	return register_tracer(&bts_tracer);
	194	}
	195	device_initcall(init_bts_trace);