[linux-block.git] / kernel / trace / trace_irqsoff.c

/*
 * trace irqs off criticall timings
 *
 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
 *
 * From code in the latency_tracer, that is:
 *
 *  Copyright (C) 2004-2006 Ingo Molnar
 *  Copyright (C) 2004 William Lee Irwin III
 */
#include <linux/kallsyms.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/ftrace.h>
#include <linux/fs.h>

#include "trace.h"

static struct trace_array		*irqsoff_trace __read_mostly;
static int				tracer_enabled __read_mostly;

static DEFINE_PER_CPU(int, tracing_cpu);

static DEFINE_SPINLOCK(max_trace_lock);

enum {
	TRACER_IRQS_OFF		= (1 << 1),
	TRACER_PREEMPT_OFF	= (1 << 2),
};

static int trace_type __read_mostly;

#ifdef CONFIG_PREEMPT_TRACER
static inline int
preempt_trace(void)
{
	return ((trace_type & TRACER_PREEMPT_OFF) && preempt_count());
}
#else
# define preempt_trace() (0)
#endif

#ifdef CONFIG_IRQSOFF_TRACER
static inline int
irq_trace(void)
{
	return ((trace_type & TRACER_IRQS_OFF) &&
		irqs_disabled());
}
#else
# define irq_trace() (0)
#endif

/*
 * Sequence count - we record it when starting a measurement and
 * skip the latency if the sequence has changed - some other section
 * did a maximum and could disturb our measurement with serial console
 * printouts, etc. Truly coinciding maximum latencies should be rare
 * and what happens together happens separately as well, so this doesnt
 * decrease the validity of the maximum found:
 */
static __cacheline_aligned_in_smp	unsigned long max_sequence;

#ifdef CONFIG_FUNCTION_TRACER
/*
 * irqsoff uses its own tracer function to keep the overhead down:
 */
static void
irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip)
{
	struct trace_array *tr = irqsoff_trace;
	struct trace_array_cpu *data;
	unsigned long flags;
	long disabled;
	int cpu;

	/*
	 * Does not matter if we preempt. We test the flags
	 * afterward, to see if irqs are disabled or not.
	 * If we preempt and get a false positive, the flags
	 * test will fail.
	 */
	cpu = raw_smp_processor_id();
	if (likely(!per_cpu(tracing_cpu, cpu)))
		return;

	local_save_flags(flags);
	/* slight chance to get a false positive on tracing_cpu */
	if (!irqs_disabled_flags(flags))
		return;

	data = tr->data[cpu];
	disabled = atomic_inc_return(&data->disabled);

	if (likely(disabled == 1))
		trace_function(tr, data, ip, parent_ip, flags, preempt_count());

	atomic_dec(&data->disabled);
}

static struct ftrace_ops trace_ops __read_mostly =
{
	.func = irqsoff_tracer_call,
};
#endif /* CONFIG_FUNCTION_TRACER */

/*
 * Should this new latency be reported/recorded?
 */
static int report_latency(cycle_t delta)
{
	if (tracing_thresh) {
		if (delta < tracing_thresh)
			return 0;
	} else {
		if (delta <= tracing_max_latency)
			return 0;
	}
	return 1;
}

static void
check_critical_timing(struct trace_array *tr,
		      struct trace_array_cpu *data,
		      unsigned long parent_ip,
		      int cpu)
{
	unsigned long latency, t0, t1;
	cycle_t T0, T1, delta;
	unsigned long flags;
	int pc;

	/*
	 * usecs conversion is slow so we try to delay the conversion
	 * as long as possible:
	 */
	T0 = data->preempt_timestamp;
	T1 = ftrace_now(cpu);
	delta = T1-T0;

	local_save_flags(flags);

	pc = preempt_count();

	if (!report_latency(delta))
		goto out;

	spin_lock_irqsave(&max_trace_lock, flags);

	/* check if we are still the max latency */
	if (!report_latency(delta))
		goto out_unlock;

	trace_function(tr, data, CALLER_ADDR0, parent_ip, flags, pc);

	latency = nsecs_to_usecs(delta);

	if (data->critical_sequence != max_sequence)
		goto out_unlock;

	tracing_max_latency = delta;
	t0 = nsecs_to_usecs(T0);
	t1 = nsecs_to_usecs(T1);

	data->critical_end = parent_ip;

	update_max_tr_single(tr, current, cpu);

	max_sequence++;

out_unlock:
	spin_unlock_irqrestore(&max_trace_lock, flags);

out:
	data->critical_sequence = max_sequence;
	data->preempt_timestamp = ftrace_now(cpu);
	tracing_reset(tr, cpu);
	trace_function(tr, data, CALLER_ADDR0, parent_ip, flags, pc);
}

static inline void
start_critical_timing(unsigned long ip, unsigned long parent_ip)
{
	int cpu;
	struct trace_array *tr = irqsoff_trace;
	struct trace_array_cpu *data;
	unsigned long flags;

	if (likely(!tracer_enabled))
		return;

	cpu = raw_smp_processor_id();

	if (per_cpu(tracing_cpu, cpu))
		return;

	data = tr->data[cpu];

	if (unlikely(!data) || atomic_read(&data->disabled))
		return;

	atomic_inc(&data->disabled);

	data->critical_sequence = max_sequence;
	data->preempt_timestamp = ftrace_now(cpu);
	data->critical_start = parent_ip ? : ip;
	tracing_reset(tr, cpu);

	local_save_flags(flags);

	trace_function(tr, data, ip, parent_ip, flags, preempt_count());

	per_cpu(tracing_cpu, cpu) = 1;

	atomic_dec(&data->disabled);
}

static inline void
stop_critical_timing(unsigned long ip, unsigned long parent_ip)
{
	int cpu;
	struct trace_array *tr = irqsoff_trace;
	struct trace_array_cpu *data;
	unsigned long flags;

	cpu = raw_smp_processor_id();
	/* Always clear the tracing cpu on stopping the trace */
	if (unlikely(per_cpu(tracing_cpu, cpu)))
		per_cpu(tracing_cpu, cpu) = 0;
	else
		return;

	if (!tracer_enabled)
		return;

	data = tr->data[cpu];

	if (unlikely(!data) ||
	    !data->critical_start || atomic_read(&data->disabled))
		return;

	atomic_inc(&data->disabled);

	local_save_flags(flags);
	trace_function(tr, data, ip, parent_ip, flags, preempt_count());
	check_critical_timing(tr, data, parent_ip ? : ip, cpu);
	data->critical_start = 0;
	atomic_dec(&data->disabled);
}

/* start and stop critical timings used to for stoppage (in idle) */
void start_critical_timings(void)
{
	if (preempt_trace() || irq_trace())
		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
}
EXPORT_SYMBOL_GPL(start_critical_timings);

void stop_critical_timings(void)
{
	if (preempt_trace() || irq_trace())
		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
}
EXPORT_SYMBOL_GPL(stop_critical_timings);

#ifdef CONFIG_IRQSOFF_TRACER
#ifdef CONFIG_PROVE_LOCKING
void time_hardirqs_on(unsigned long a0, unsigned long a1)
{
	if (!preempt_trace() && irq_trace())
		stop_critical_timing(a0, a1);
}

void time_hardirqs_off(unsigned long a0, unsigned long a1)
{
	if (!preempt_trace() && irq_trace())
		start_critical_timing(a0, a1);
}

#else /* !CONFIG_PROVE_LOCKING */

/*
 * Stubs:
 */

void early_boot_irqs_off(void)
{
}

void early_boot_irqs_on(void)
{
}

void trace_softirqs_on(unsigned long ip)
{
}

void trace_softirqs_off(unsigned long ip)
{
}

inline void print_irqtrace_events(struct task_struct *curr)
{
}

/*
 * We are only interested in hardirq on/off events:
 */
void trace_hardirqs_on(void)
{
	if (!preempt_trace() && irq_trace())
		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
}
EXPORT_SYMBOL(trace_hardirqs_on);

void trace_hardirqs_off(void)
{
	if (!preempt_trace() && irq_trace())
		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
}
EXPORT_SYMBOL(trace_hardirqs_off);

void trace_hardirqs_on_caller(unsigned long caller_addr)
{
	if (!preempt_trace() && irq_trace())
		stop_critical_timing(CALLER_ADDR0, caller_addr);
}
EXPORT_SYMBOL(trace_hardirqs_on_caller);

void trace_hardirqs_off_caller(unsigned long caller_addr)
{
	if (!preempt_trace() && irq_trace())
		start_critical_timing(CALLER_ADDR0, caller_addr);
}
EXPORT_SYMBOL(trace_hardirqs_off_caller);

#endif /* CONFIG_PROVE_LOCKING */
#endif /*  CONFIG_IRQSOFF_TRACER */

#ifdef CONFIG_PREEMPT_TRACER
void trace_preempt_on(unsigned long a0, unsigned long a1)
{
	if (preempt_trace())
		stop_critical_timing(a0, a1);
}

void trace_preempt_off(unsigned long a0, unsigned long a1)
{
	if (preempt_trace())
		start_critical_timing(a0, a1);
}
#endif /* CONFIG_PREEMPT_TRACER */

/*
 * save_tracer_enabled is used to save the state of the tracer_enabled
 * variable when we disable it when we open a trace output file.
 */
static int save_tracer_enabled;

static void start_irqsoff_tracer(struct trace_array *tr)
{
	register_ftrace_function(&trace_ops);
	if (tracing_is_enabled()) {
		tracer_enabled = 1;
		save_tracer_enabled = 1;
	} else {
		tracer_enabled = 0;
		save_tracer_enabled = 0;
	}
}

static void stop_irqsoff_tracer(struct trace_array *tr)
{
	tracer_enabled = 0;
	save_tracer_enabled = 0;
	unregister_ftrace_function(&trace_ops);
}

static void __irqsoff_tracer_init(struct trace_array *tr)
{
	tracing_max_latency = 0;
	irqsoff_trace = tr;
	/* make sure that the tracer is visible */
	smp_wmb();
	start_irqsoff_tracer(tr);
}

static void irqsoff_tracer_reset(struct trace_array *tr)
{
	stop_irqsoff_tracer(tr);
}

static void irqsoff_tracer_start(struct trace_array *tr)
{
	tracer_enabled = 1;
	save_tracer_enabled = 1;
}

static void irqsoff_tracer_stop(struct trace_array *tr)
{
	tracer_enabled = 0;
	save_tracer_enabled = 0;
}

static void irqsoff_tracer_open(struct trace_iterator *iter)
{
	/* stop the trace while dumping */
	tracer_enabled = 0;
}

static void irqsoff_tracer_close(struct trace_iterator *iter)
{
	/* restart tracing */
	tracer_enabled = save_tracer_enabled;
}

#ifdef CONFIG_IRQSOFF_TRACER
static int irqsoff_tracer_init(struct trace_array *tr)
{
	trace_type = TRACER_IRQS_OFF;

	__irqsoff_tracer_init(tr);
	return 0;
}
static struct tracer irqsoff_tracer __read_mostly =
{
	.name		= "irqsoff",
	.init		= irqsoff_tracer_init,
	.reset		= irqsoff_tracer_reset,
	.start		= irqsoff_tracer_start,
	.stop		= irqsoff_tracer_stop,
	.open		= irqsoff_tracer_open,
	.close		= irqsoff_tracer_close,
	.print_max	= 1,
#ifdef CONFIG_FTRACE_SELFTEST
	.selftest    = trace_selftest_startup_irqsoff,
#endif
};
# define register_irqsoff(trace) register_tracer(&trace)
#else
# define register_irqsoff(trace) do { } while (0)
#endif

#ifdef CONFIG_PREEMPT_TRACER
static int preemptoff_tracer_init(struct trace_array *tr)
{
	trace_type = TRACER_PREEMPT_OFF;

	__irqsoff_tracer_init(tr);
	return 0;
}

static struct tracer preemptoff_tracer __read_mostly =
{
	.name		= "preemptoff",
	.init		= preemptoff_tracer_init,
	.reset		= irqsoff_tracer_reset,
	.start		= irqsoff_tracer_start,
	.stop		= irqsoff_tracer_stop,
	.open		= irqsoff_tracer_open,
	.close		= irqsoff_tracer_close,
	.print_max	= 1,
#ifdef CONFIG_FTRACE_SELFTEST
	.selftest    = trace_selftest_startup_preemptoff,
#endif
};
# define register_preemptoff(trace) register_tracer(&trace)
#else
# define register_preemptoff(trace) do { } while (0)
#endif

#if defined(CONFIG_IRQSOFF_TRACER) && \
	defined(CONFIG_PREEMPT_TRACER)

static int preemptirqsoff_tracer_init(struct trace_array *tr)
{
	trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;

	__irqsoff_tracer_init(tr);
	return 0;
}

static struct tracer preemptirqsoff_tracer __read_mostly =
{
	.name		= "preemptirqsoff",
	.init		= preemptirqsoff_tracer_init,
	.reset		= irqsoff_tracer_reset,
	.start		= irqsoff_tracer_start,
	.stop		= irqsoff_tracer_stop,
	.open		= irqsoff_tracer_open,
	.close		= irqsoff_tracer_close,
	.print_max	= 1,
#ifdef CONFIG_FTRACE_SELFTEST
	.selftest    = trace_selftest_startup_preemptirqsoff,
#endif
};

# define register_preemptirqsoff(trace) register_tracer(&trace)
#else
# define register_preemptirqsoff(trace) do { } while (0)
#endif

__init static int init_irqsoff_tracer(void)
{
	register_irqsoff(irqsoff_tracer);
	register_preemptoff(preemptoff_tracer);
	register_preemptirqsoff(preemptirqsoff_tracer);

	return 0;
}
device_initcall(init_irqsoff_tracer);
Commit	Line	Data
81d68a96 SR	1	/*
	2	* trace irqs off criticall timings
	3	*
	4	* Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
	5	* Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
	6	*
	7	* From code in the latency_tracer, that is:
	8	*
	9	* Copyright (C) 2004-2006 Ingo Molnar
	10	* Copyright (C) 2004 William Lee Irwin III
	11	*/
	12	#include <linux/kallsyms.h>
	13	#include <linux/debugfs.h>
	14	#include <linux/uaccess.h>
	15	#include <linux/module.h>
	16	#include <linux/ftrace.h>
	17	#include <linux/fs.h>
	18
	19	#include "trace.h"
	20
	21	static struct trace_array *irqsoff_trace __read_mostly;
	22	static int tracer_enabled __read_mostly;
	23
6cd8a4bb SR	24	static DEFINE_PER_CPU(int, tracing_cpu);
6cd8a4bb SR	25
89b2f978 SR	26	static DEFINE_SPINLOCK(max_trace_lock);
89b2f978 SR	27
6cd8a4bb SR	28	enum {
	29	TRACER_IRQS_OFF = (1 << 1),
	30	TRACER_PREEMPT_OFF = (1 << 2),
	31	};
	32
	33	static int trace_type __read_mostly;
	34
	35	#ifdef CONFIG_PREEMPT_TRACER
e309b41d	36	static inline int
6cd8a4bb SR	37	preempt_trace(void)
	38	{
	39	return ((trace_type & TRACER_PREEMPT_OFF) && preempt_count());
	40	}
	41	#else
	42	# define preempt_trace() (0)
	43	#endif
	44
	45	#ifdef CONFIG_IRQSOFF_TRACER
e309b41d	46	static inline int
6cd8a4bb SR	47	irq_trace(void)
	48	{
	49	return ((trace_type & TRACER_IRQS_OFF) &&
	50	irqs_disabled());
	51	}
	52	#else
	53	# define irq_trace() (0)
	54	#endif
	55
81d68a96 SR	56	/*
	57	* Sequence count - we record it when starting a measurement and
	58	* skip the latency if the sequence has changed - some other section
	59	* did a maximum and could disturb our measurement with serial console
	60	* printouts, etc. Truly coinciding maximum latencies should be rare
	61	* and what happens together happens separately as well, so this doesnt
	62	* decrease the validity of the maximum found:
	63	*/
	64	static __cacheline_aligned_in_smp unsigned long max_sequence;
	65
606576ce	66	#ifdef CONFIG_FUNCTION_TRACER
81d68a96 SR	67	/*
	68	* irqsoff uses its own tracer function to keep the overhead down:
	69	*/
e309b41d	70	static void
81d68a96 SR	71	irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip)
	72	{
	73	struct trace_array *tr = irqsoff_trace;
	74	struct trace_array_cpu *data;
	75	unsigned long flags;
	76	long disabled;
	77	int cpu;
	78
361943ad SR	79	/*
	80	* Does not matter if we preempt. We test the flags
	81	* afterward, to see if irqs are disabled or not.
	82	* If we preempt and get a false positive, the flags
	83	* test will fail.
	84	*/
	85	cpu = raw_smp_processor_id();
	86	if (likely(!per_cpu(tracing_cpu, cpu)))
81d68a96 SR	87	return;
	88
	89	local_save_flags(flags);
361943ad SR	90	/* slight chance to get a false positive on tracing_cpu */
	91	if (!irqs_disabled_flags(flags))
	92	return;
81d68a96	93
81d68a96 SR	94	data = tr->data[cpu];
	95	disabled = atomic_inc_return(&data->disabled);
	96
	97	if (likely(disabled == 1))
38697053	98	trace_function(tr, data, ip, parent_ip, flags, preempt_count());
81d68a96 SR	99
	100	atomic_dec(&data->disabled);
	101	}
	102
	103	static struct ftrace_ops trace_ops __read_mostly =
	104	{
	105	.func = irqsoff_tracer_call,
	106	};
606576ce	107	#endif /* CONFIG_FUNCTION_TRACER */
81d68a96 SR	108
	109	/*
	110	* Should this new latency be reported/recorded?
	111	*/
e309b41d	112	static int report_latency(cycle_t delta)
81d68a96 SR	113	{
	114	if (tracing_thresh) {
	115	if (delta < tracing_thresh)
	116	return 0;
	117	} else {
	118	if (delta <= tracing_max_latency)
	119	return 0;
	120	}
	121	return 1;
	122	}
	123
e309b41d	124	static void
81d68a96 SR	125	check_critical_timing(struct trace_array *tr,
	126	struct trace_array_cpu *data,
	127	unsigned long parent_ip,
	128	int cpu)
	129	{
	130	unsigned long latency, t0, t1;
89b2f978	131	cycle_t T0, T1, delta;
81d68a96	132	unsigned long flags;
38697053	133	int pc;
81d68a96 SR	134
	135	/*
	136	* usecs conversion is slow so we try to delay the conversion
	137	* as long as possible:
	138	*/
	139	T0 = data->preempt_timestamp;
750ed1a4	140	T1 = ftrace_now(cpu);
81d68a96 SR	141	delta = T1-T0;
	142
	143	local_save_flags(flags);
	144
6450c1d3 SR	145	pc = preempt_count();
6450c1d3 SR	146
81d68a96 SR	147	if (!report_latency(delta))
	148	goto out;
	149
c7aafc54	150	spin_lock_irqsave(&max_trace_lock, flags);
81d68a96	151
89b2f978 SR	152	/* check if we are still the max latency */
	153	if (!report_latency(delta))
	154	goto out_unlock;
	155
38697053	156	trace_function(tr, data, CALLER_ADDR0, parent_ip, flags, pc);
81d68a96 SR	157
	158	latency = nsecs_to_usecs(delta);
	159
	160	if (data->critical_sequence != max_sequence)
89b2f978	161	goto out_unlock;
81d68a96 SR	162
	163	tracing_max_latency = delta;
	164	t0 = nsecs_to_usecs(T0);
	165	t1 = nsecs_to_usecs(T1);
	166
	167	data->critical_end = parent_ip;
	168
	169	update_max_tr_single(tr, current, cpu);
	170
81d68a96 SR	171	max_sequence++;
81d68a96 SR	172
89b2f978	173	out_unlock:
c7aafc54	174	spin_unlock_irqrestore(&max_trace_lock, flags);
89b2f978	175
81d68a96 SR	176	out:
81d68a96 SR	177	data->critical_sequence = max_sequence;
750ed1a4	178	data->preempt_timestamp = ftrace_now(cpu);
3928a8a2	179	tracing_reset(tr, cpu);
38697053	180	trace_function(tr, data, CALLER_ADDR0, parent_ip, flags, pc);
81d68a96 SR	181	}
81d68a96 SR	182
e309b41d	183	static inline void
81d68a96 SR	184	start_critical_timing(unsigned long ip, unsigned long parent_ip)
	185	{
	186	int cpu;
	187	struct trace_array *tr = irqsoff_trace;
	188	struct trace_array_cpu *data;
	189	unsigned long flags;
	190
	191	if (likely(!tracer_enabled))
	192	return;
	193
c5f888ca SR	194	cpu = raw_smp_processor_id();
	195
	196	if (per_cpu(tracing_cpu, cpu))
6cd8a4bb SR	197	return;
6cd8a4bb SR	198
81d68a96 SR	199	data = tr->data[cpu];
81d68a96 SR	200
c5f888ca	201	if (unlikely(!data) \|\| atomic_read(&data->disabled))
81d68a96 SR	202	return;
	203
	204	atomic_inc(&data->disabled);
	205
	206	data->critical_sequence = max_sequence;
750ed1a4	207	data->preempt_timestamp = ftrace_now(cpu);
6cd8a4bb	208	data->critical_start = parent_ip ? : ip;
3928a8a2	209	tracing_reset(tr, cpu);
81d68a96 SR	210
81d68a96 SR	211	local_save_flags(flags);
6cd8a4bb	212
38697053	213	trace_function(tr, data, ip, parent_ip, flags, preempt_count());
81d68a96	214
c5f888ca	215	per_cpu(tracing_cpu, cpu) = 1;
6cd8a4bb	216
81d68a96 SR	217	atomic_dec(&data->disabled);
	218	}
	219
e309b41d	220	static inline void
81d68a96 SR	221	stop_critical_timing(unsigned long ip, unsigned long parent_ip)
	222	{
	223	int cpu;
	224	struct trace_array *tr = irqsoff_trace;
	225	struct trace_array_cpu *data;
	226	unsigned long flags;
	227
c5f888ca	228	cpu = raw_smp_processor_id();
6cd8a4bb	229	/* Always clear the tracing cpu on stopping the trace */
c5f888ca SR	230	if (unlikely(per_cpu(tracing_cpu, cpu)))
c5f888ca SR	231	per_cpu(tracing_cpu, cpu) = 0;
6cd8a4bb SR	232	else
	233	return;
	234
	235	if (!tracer_enabled)
81d68a96 SR	236	return;
81d68a96 SR	237
81d68a96 SR	238	data = tr->data[cpu];
81d68a96 SR	239
3928a8a2	240	if (unlikely(!data) \|\|
81d68a96 SR	241	!data->critical_start \|\| atomic_read(&data->disabled))
	242	return;
	243
	244	atomic_inc(&data->disabled);
c5f888ca	245
81d68a96	246	local_save_flags(flags);
38697053	247	trace_function(tr, data, ip, parent_ip, flags, preempt_count());
6cd8a4bb	248	check_critical_timing(tr, data, parent_ip ? : ip, cpu);
81d68a96 SR	249	data->critical_start = 0;
	250	atomic_dec(&data->disabled);
	251	}
	252
6cd8a4bb	253	/* start and stop critical timings used to for stoppage (in idle) */
e309b41d	254	void start_critical_timings(void)
81d68a96	255	{
6cd8a4bb	256	if (preempt_trace() \|\| irq_trace())
81d68a96 SR	257	start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
81d68a96 SR	258	}
1fe37104	259	EXPORT_SYMBOL_GPL(start_critical_timings);
81d68a96	260
e309b41d	261	void stop_critical_timings(void)
81d68a96	262	{
6cd8a4bb	263	if (preempt_trace() \|\| irq_trace())
81d68a96 SR	264	stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
81d68a96 SR	265	}
1fe37104	266	EXPORT_SYMBOL_GPL(stop_critical_timings);
81d68a96	267
6cd8a4bb	268	#ifdef CONFIG_IRQSOFF_TRACER
81d68a96	269	#ifdef CONFIG_PROVE_LOCKING
e309b41d	270	void time_hardirqs_on(unsigned long a0, unsigned long a1)
81d68a96	271	{
6cd8a4bb	272	if (!preempt_trace() && irq_trace())
81d68a96 SR	273	stop_critical_timing(a0, a1);
	274	}
	275
e309b41d	276	void time_hardirqs_off(unsigned long a0, unsigned long a1)
81d68a96	277	{
6cd8a4bb	278	if (!preempt_trace() && irq_trace())
81d68a96 SR	279	start_critical_timing(a0, a1);
	280	}
	281
	282	#else /* !CONFIG_PROVE_LOCKING */
	283
	284	/*
	285	* Stubs:
	286	*/
	287
	288	void early_boot_irqs_off(void)
	289	{
	290	}
	291
	292	void early_boot_irqs_on(void)
	293	{
	294	}
	295
	296	void trace_softirqs_on(unsigned long ip)
	297	{
	298	}
	299
	300	void trace_softirqs_off(unsigned long ip)
	301	{
	302	}
	303
e309b41d	304	inline void print_irqtrace_events(struct task_struct *curr)
81d68a96 SR	305	{
	306	}
	307
	308	/*
	309	* We are only interested in hardirq on/off events:
	310	*/
e309b41d	311	void trace_hardirqs_on(void)
81d68a96	312	{
6cd8a4bb	313	if (!preempt_trace() && irq_trace())
81d68a96 SR	314	stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
	315	}
	316	EXPORT_SYMBOL(trace_hardirqs_on);
	317
e309b41d	318	void trace_hardirqs_off(void)
81d68a96	319	{
6cd8a4bb	320	if (!preempt_trace() && irq_trace())
81d68a96 SR	321	start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
	322	}
	323	EXPORT_SYMBOL(trace_hardirqs_off);
	324
e309b41d	325	void trace_hardirqs_on_caller(unsigned long caller_addr)
81d68a96	326	{
6cd8a4bb	327	if (!preempt_trace() && irq_trace())
81d68a96 SR	328	stop_critical_timing(CALLER_ADDR0, caller_addr);
	329	}
	330	EXPORT_SYMBOL(trace_hardirqs_on_caller);
	331
e309b41d	332	void trace_hardirqs_off_caller(unsigned long caller_addr)
81d68a96	333	{
6cd8a4bb	334	if (!preempt_trace() && irq_trace())
81d68a96 SR	335	start_critical_timing(CALLER_ADDR0, caller_addr);
	336	}
	337	EXPORT_SYMBOL(trace_hardirqs_off_caller);
	338
	339	#endif /* CONFIG_PROVE_LOCKING */
6cd8a4bb SR	340	#endif /* CONFIG_IRQSOFF_TRACER */
	341
	342	#ifdef CONFIG_PREEMPT_TRACER
e309b41d	343	void trace_preempt_on(unsigned long a0, unsigned long a1)
6cd8a4bb	344	{
1e01cb0c SR	345	if (preempt_trace())
1e01cb0c SR	346	stop_critical_timing(a0, a1);
6cd8a4bb SR	347	}
6cd8a4bb SR	348
e309b41d	349	void trace_preempt_off(unsigned long a0, unsigned long a1)
6cd8a4bb	350	{
1e01cb0c SR	351	if (preempt_trace())
1e01cb0c SR	352	start_critical_timing(a0, a1);
6cd8a4bb SR	353	}
6cd8a4bb SR	354	#endif /* CONFIG_PREEMPT_TRACER */
81d68a96	355
9036990d SR	356	/*
	357	* save_tracer_enabled is used to save the state of the tracer_enabled
	358	* variable when we disable it when we open a trace output file.
	359	*/
	360	static int save_tracer_enabled;
	361
81d68a96 SR	362	static void start_irqsoff_tracer(struct trace_array *tr)
81d68a96 SR	363	{
81d68a96	364	register_ftrace_function(&trace_ops);
9036990d SR	365	if (tracing_is_enabled()) {
	366	tracer_enabled = 1;
	367	save_tracer_enabled = 1;
	368	} else {
	369	tracer_enabled = 0;
	370	save_tracer_enabled = 0;
	371	}
81d68a96 SR	372	}
	373
	374	static void stop_irqsoff_tracer(struct trace_array *tr)
	375	{
81d68a96	376	tracer_enabled = 0;
9036990d	377	save_tracer_enabled = 0;
89b2f978	378	unregister_ftrace_function(&trace_ops);
81d68a96 SR	379	}
81d68a96 SR	380
6cd8a4bb	381	static void __irqsoff_tracer_init(struct trace_array *tr)
81d68a96	382	{
1092307d	383	tracing_max_latency = 0;
81d68a96	384	irqsoff_trace = tr;
c5f888ca	385	/* make sure that the tracer is visible */
81d68a96	386	smp_wmb();
c76f0694	387	start_irqsoff_tracer(tr);
81d68a96 SR	388	}
	389
	390	static void irqsoff_tracer_reset(struct trace_array *tr)
	391	{
c76f0694	392	stop_irqsoff_tracer(tr);
81d68a96 SR	393	}
81d68a96 SR	394
9036990d SR	395	static void irqsoff_tracer_start(struct trace_array *tr)
9036990d SR	396	{
9036990d SR	397	tracer_enabled = 1;
	398	save_tracer_enabled = 1;
	399	}
	400
	401	static void irqsoff_tracer_stop(struct trace_array *tr)
	402	{
	403	tracer_enabled = 0;
	404	save_tracer_enabled = 0;
	405	}
	406
e309b41d	407	static void irqsoff_tracer_open(struct trace_iterator *iter)
81d68a96 SR	408	{
81d68a96 SR	409	/* stop the trace while dumping */
9036990d	410	tracer_enabled = 0;
81d68a96 SR	411	}
81d68a96 SR	412
e309b41d	413	static void irqsoff_tracer_close(struct trace_iterator *iter)
81d68a96	414	{
9036990d SR	415	/* restart tracing */
9036990d SR	416	tracer_enabled = save_tracer_enabled;
81d68a96 SR	417	}
81d68a96 SR	418
6cd8a4bb	419	#ifdef CONFIG_IRQSOFF_TRACER
1c80025a	420	static int irqsoff_tracer_init(struct trace_array *tr)
6cd8a4bb SR	421	{
	422	trace_type = TRACER_IRQS_OFF;
	423
	424	__irqsoff_tracer_init(tr);
1c80025a	425	return 0;
6cd8a4bb	426	}
81d68a96 SR	427	static struct tracer irqsoff_tracer __read_mostly =
	428	{
	429	.name = "irqsoff",
	430	.init = irqsoff_tracer_init,
	431	.reset = irqsoff_tracer_reset,
9036990d SR	432	.start = irqsoff_tracer_start,
9036990d SR	433	.stop = irqsoff_tracer_stop,
81d68a96 SR	434	.open = irqsoff_tracer_open,
81d68a96 SR	435	.close = irqsoff_tracer_close,
81d68a96	436	.print_max = 1,
60a11774 SR	437	#ifdef CONFIG_FTRACE_SELFTEST
	438	.selftest = trace_selftest_startup_irqsoff,
	439	#endif
81d68a96	440	};
6cd8a4bb SR	441	# define register_irqsoff(trace) register_tracer(&trace)
	442	#else
	443	# define register_irqsoff(trace) do { } while (0)
	444	#endif
	445
	446	#ifdef CONFIG_PREEMPT_TRACER
1c80025a	447	static int preemptoff_tracer_init(struct trace_array *tr)
6cd8a4bb SR	448	{
	449	trace_type = TRACER_PREEMPT_OFF;
	450
	451	__irqsoff_tracer_init(tr);
1c80025a	452	return 0;
6cd8a4bb SR	453	}
	454
	455	static struct tracer preemptoff_tracer __read_mostly =
	456	{
	457	.name = "preemptoff",
	458	.init = preemptoff_tracer_init,
	459	.reset = irqsoff_tracer_reset,
9036990d SR	460	.start = irqsoff_tracer_start,
9036990d SR	461	.stop = irqsoff_tracer_stop,
6cd8a4bb SR	462	.open = irqsoff_tracer_open,
6cd8a4bb SR	463	.close = irqsoff_tracer_close,
6cd8a4bb	464	.print_max = 1,
60a11774 SR	465	#ifdef CONFIG_FTRACE_SELFTEST
	466	.selftest = trace_selftest_startup_preemptoff,
	467	#endif
6cd8a4bb SR	468	};
	469	# define register_preemptoff(trace) register_tracer(&trace)
	470	#else
	471	# define register_preemptoff(trace) do { } while (0)
	472	#endif
	473
	474	#if defined(CONFIG_IRQSOFF_TRACER) && \
	475	defined(CONFIG_PREEMPT_TRACER)
	476
1c80025a	477	static int preemptirqsoff_tracer_init(struct trace_array *tr)
6cd8a4bb SR	478	{
	479	trace_type = TRACER_IRQS_OFF \| TRACER_PREEMPT_OFF;
	480
	481	__irqsoff_tracer_init(tr);
1c80025a	482	return 0;
6cd8a4bb SR	483	}
	484
	485	static struct tracer preemptirqsoff_tracer __read_mostly =
	486	{
	487	.name = "preemptirqsoff",
	488	.init = preemptirqsoff_tracer_init,
	489	.reset = irqsoff_tracer_reset,
9036990d SR	490	.start = irqsoff_tracer_start,
9036990d SR	491	.stop = irqsoff_tracer_stop,
6cd8a4bb SR	492	.open = irqsoff_tracer_open,
6cd8a4bb SR	493	.close = irqsoff_tracer_close,
6cd8a4bb	494	.print_max = 1,
60a11774 SR	495	#ifdef CONFIG_FTRACE_SELFTEST
	496	.selftest = trace_selftest_startup_preemptirqsoff,
	497	#endif
6cd8a4bb SR	498	};
	499
	500	# define register_preemptirqsoff(trace) register_tracer(&trace)
	501	#else
	502	# define register_preemptirqsoff(trace) do { } while (0)
	503	#endif
81d68a96 SR	504
	505	__init static int init_irqsoff_tracer(void)
	506	{
6cd8a4bb SR	507	register_irqsoff(irqsoff_tracer);
	508	register_preemptoff(preemptoff_tracer);
	509	register_preemptirqsoff(preemptirqsoff_tracer);
81d68a96 SR	510
	511	return 0;
	512	}
	513	device_initcall(init_irqsoff_tracer);