[mirror_ubuntu-bionic-kernel.git] / drivers / oprofile / cpu_buffer.c

/**
 * @file cpu_buffer.c
 *
 * @remark Copyright 2002-2009 OProfile authors
 * @remark Read the file COPYING
 *
 * @author John Levon <levon@movementarian.org>
 * @author Barry Kasindorf <barry.kasindorf@amd.com>
 * @author Robert Richter <robert.richter@amd.com>
 *
 * Each CPU has a local buffer that stores PC value/event
 * pairs. We also log context switches when we notice them.
 * Eventually each CPU's buffer is processed into the global
 * event buffer by sync_buffer().
 *
 * We use a local buffer for two reasons: an NMI or similar
 * interrupt cannot synchronise, and high sampling rates
 * would lead to catastrophic global synchronisation if
 * a global buffer was used.
 */

#include <linux/sched.h>
#include <linux/oprofile.h>
#include <linux/errno.h>

#include <asm/ptrace.h>

#include "event_buffer.h"
#include "cpu_buffer.h"
#include "buffer_sync.h"
#include "oprof.h"

#define OP_BUFFER_FLAGS	0

static struct ring_buffer *op_ring_buffer;
DEFINE_PER_CPU(struct oprofile_cpu_buffer, op_cpu_buffer);

static void wq_sync_buffer(struct work_struct *work);

#define DEFAULT_TIMER_EXPIRE (HZ / 10)
static int work_enabled;

unsigned long oprofile_get_cpu_buffer_size(void)
{
	return oprofile_cpu_buffer_size;
}

void oprofile_cpu_buffer_inc_smpl_lost(void)
{
	struct oprofile_cpu_buffer *cpu_buf = this_cpu_ptr(&op_cpu_buffer);

	cpu_buf->sample_lost_overflow++;
}

void free_cpu_buffers(void)
{
	if (op_ring_buffer)
		ring_buffer_free(op_ring_buffer);
	op_ring_buffer = NULL;
}

#define RB_EVENT_HDR_SIZE 4

int alloc_cpu_buffers(void)
{
	int i;

	unsigned long buffer_size = oprofile_cpu_buffer_size;
	unsigned long byte_size = buffer_size * (sizeof(struct op_sample) +
						 RB_EVENT_HDR_SIZE);

	op_ring_buffer = ring_buffer_alloc(byte_size, OP_BUFFER_FLAGS);
	if (!op_ring_buffer)
		goto fail;

	for_each_possible_cpu(i) {
		struct oprofile_cpu_buffer *b = &per_cpu(op_cpu_buffer, i);

		b->last_task = NULL;
		b->last_is_kernel = -1;
		b->tracing = 0;
		b->buffer_size = buffer_size;
		b->sample_received = 0;
		b->sample_lost_overflow = 0;
		b->backtrace_aborted = 0;
		b->sample_invalid_eip = 0;
		b->cpu = i;
		INIT_DELAYED_WORK(&b->work, wq_sync_buffer);
	}
	return 0;

fail:
	free_cpu_buffers();
	return -ENOMEM;
}

void start_cpu_work(void)
{
	int i;

	work_enabled = 1;

	for_each_online_cpu(i) {
		struct oprofile_cpu_buffer *b = &per_cpu(op_cpu_buffer, i);

		/*
		 * Spread the work by 1 jiffy per cpu so they dont all
		 * fire at once.
		 */
		schedule_delayed_work_on(i, &b->work, DEFAULT_TIMER_EXPIRE + i);
	}
}

void end_cpu_work(void)
{
	work_enabled = 0;
}

void flush_cpu_work(void)
{
	int i;

	for_each_online_cpu(i) {
		struct oprofile_cpu_buffer *b = &per_cpu(op_cpu_buffer, i);

		/* these works are per-cpu, no need for flush_sync */
		flush_delayed_work(&b->work);
	}
}

/*
 * This function prepares the cpu buffer to write a sample.
 *
 * Struct op_entry is used during operations on the ring buffer while
 * struct op_sample contains the data that is stored in the ring
 * buffer. Struct entry can be uninitialized. The function reserves a
 * data array that is specified by size. Use
 * op_cpu_buffer_write_commit() after preparing the sample. In case of
 * errors a null pointer is returned, otherwise the pointer to the
 * sample.
 *
 */
struct op_sample
*op_cpu_buffer_write_reserve(struct op_entry *entry, unsigned long size)
{
	entry->event = ring_buffer_lock_reserve
		(op_ring_buffer, sizeof(struct op_sample) +
		 size * sizeof(entry->sample->data[0]));
	if (!entry->event)
		return NULL;
	entry->sample = ring_buffer_event_data(entry->event);
	entry->size = size;
	entry->data = entry->sample->data;

	return entry->sample;
}

int op_cpu_buffer_write_commit(struct op_entry *entry)
{
	return ring_buffer_unlock_commit(op_ring_buffer, entry->event);
}

struct op_sample *op_cpu_buffer_read_entry(struct op_entry *entry, int cpu)
{
	struct ring_buffer_event *e;
	e = ring_buffer_consume(op_ring_buffer, cpu, NULL, NULL);
	if (!e)
		return NULL;

	entry->event = e;
	entry->sample = ring_buffer_event_data(e);
	entry->size = (ring_buffer_event_length(e) - sizeof(struct op_sample))
		/ sizeof(entry->sample->data[0]);
	entry->data = entry->sample->data;
	return entry->sample;
}

unsigned long op_cpu_buffer_entries(int cpu)
{
	return ring_buffer_entries_cpu(op_ring_buffer, cpu);
}

static int
op_add_code(struct oprofile_cpu_buffer *cpu_buf, unsigned long backtrace,
	    int is_kernel, struct task_struct *task)
{
	struct op_entry entry;
	struct op_sample *sample;
	unsigned long flags;
	int size;

	flags = 0;

	if (backtrace)
		flags |= TRACE_BEGIN;

	/* notice a switch from user->kernel or vice versa */
	is_kernel = !!is_kernel;
	if (cpu_buf->last_is_kernel != is_kernel) {
		cpu_buf->last_is_kernel = is_kernel;
		flags |= KERNEL_CTX_SWITCH;
		if (is_kernel)
			flags |= IS_KERNEL;
	}

	/* notice a task switch */
	if (cpu_buf->last_task != task) {
		cpu_buf->last_task = task;
		flags |= USER_CTX_SWITCH;
	}

	if (!flags)
		/* nothing to do */
		return 0;

	if (flags & USER_CTX_SWITCH)
		size = 1;
	else
		size = 0;

	sample = op_cpu_buffer_write_reserve(&entry, size);
	if (!sample)
		return -ENOMEM;

	sample->eip = ESCAPE_CODE;
	sample->event = flags;

	if (size)
		op_cpu_buffer_add_data(&entry, (unsigned long)task);

	op_cpu_buffer_write_commit(&entry);

	return 0;
}

static inline int
op_add_sample(struct oprofile_cpu_buffer *cpu_buf,
	      unsigned long pc, unsigned long event)
{
	struct op_entry entry;
	struct op_sample *sample;

	sample = op_cpu_buffer_write_reserve(&entry, 0);
	if (!sample)
		return -ENOMEM;

	sample->eip = pc;
	sample->event = event;

	return op_cpu_buffer_write_commit(&entry);
}

/*
 * This must be safe from any context.
 *
 * is_kernel is needed because on some architectures you cannot
 * tell if you are in kernel or user space simply by looking at
 * pc. We tag this in the buffer by generating kernel enter/exit
 * events whenever is_kernel changes
 */
static int
log_sample(struct oprofile_cpu_buffer *cpu_buf, unsigned long pc,
	   unsigned long backtrace, int is_kernel, unsigned long event,
	   struct task_struct *task)
{
	struct task_struct *tsk = task ? task : current;
	cpu_buf->sample_received++;

	if (pc == ESCAPE_CODE) {
		cpu_buf->sample_invalid_eip++;
		return 0;
	}

	if (op_add_code(cpu_buf, backtrace, is_kernel, tsk))
		goto fail;

	if (op_add_sample(cpu_buf, pc, event))
		goto fail;

	return 1;

fail:
	cpu_buf->sample_lost_overflow++;
	return 0;
}

static inline void oprofile_begin_trace(struct oprofile_cpu_buffer *cpu_buf)
{
	cpu_buf->tracing = 1;
}

static inline void oprofile_end_trace(struct oprofile_cpu_buffer *cpu_buf)
{
	cpu_buf->tracing = 0;
}

static inline void
__oprofile_add_ext_sample(unsigned long pc, struct pt_regs * const regs,
			  unsigned long event, int is_kernel,
			  struct task_struct *task)
{
	struct oprofile_cpu_buffer *cpu_buf = this_cpu_ptr(&op_cpu_buffer);
	unsigned long backtrace = oprofile_backtrace_depth;

	/*
	 * if log_sample() fail we can't backtrace since we lost the
	 * source of this event
	 */
	if (!log_sample(cpu_buf, pc, backtrace, is_kernel, event, task))
		/* failed */
		return;

	if (!backtrace)
		return;

	oprofile_begin_trace(cpu_buf);
	oprofile_ops.backtrace(regs, backtrace);
	oprofile_end_trace(cpu_buf);
}

void oprofile_add_ext_hw_sample(unsigned long pc, struct pt_regs * const regs,
				unsigned long event, int is_kernel,
				struct task_struct *task)
{
	__oprofile_add_ext_sample(pc, regs, event, is_kernel, task);
}

void oprofile_add_ext_sample(unsigned long pc, struct pt_regs * const regs,
			     unsigned long event, int is_kernel)
{
	__oprofile_add_ext_sample(pc, regs, event, is_kernel, NULL);
}

void oprofile_add_sample(struct pt_regs * const regs, unsigned long event)
{
	int is_kernel;
	unsigned long pc;

	if (likely(regs)) {
		is_kernel = !user_mode(regs);
		pc = profile_pc(regs);
	} else {
		is_kernel = 0;    /* This value will not be used */
		pc = ESCAPE_CODE; /* as this causes an early return. */
	}

	__oprofile_add_ext_sample(pc, regs, event, is_kernel, NULL);
}

/*
 * Add samples with data to the ring buffer.
 *
 * Use oprofile_add_data(&entry, val) to add data and
 * oprofile_write_commit(&entry) to commit the sample.
 */
void
oprofile_write_reserve(struct op_entry *entry, struct pt_regs * const regs,
		       unsigned long pc, int code, int size)
{
	struct op_sample *sample;
	int is_kernel = !user_mode(regs);
	struct oprofile_cpu_buffer *cpu_buf = this_cpu_ptr(&op_cpu_buffer);

	cpu_buf->sample_received++;

	/* no backtraces for samples with data */
	if (op_add_code(cpu_buf, 0, is_kernel, current))
		goto fail;

	sample = op_cpu_buffer_write_reserve(entry, size + 2);
	if (!sample)
		goto fail;
	sample->eip = ESCAPE_CODE;
	sample->event = 0;		/* no flags */

	op_cpu_buffer_add_data(entry, code);
	op_cpu_buffer_add_data(entry, pc);

	return;

fail:
	entry->event = NULL;
	cpu_buf->sample_lost_overflow++;
}

int oprofile_add_data(struct op_entry *entry, unsigned long val)
{
	if (!entry->event)
		return 0;
	return op_cpu_buffer_add_data(entry, val);
}

int oprofile_add_data64(struct op_entry *entry, u64 val)
{
	if (!entry->event)
		return 0;
	if (op_cpu_buffer_get_size(entry) < 2)
		/*
		 * the function returns 0 to indicate a too small
		 * buffer, even if there is some space left
		 */
		return 0;
	if (!op_cpu_buffer_add_data(entry, (u32)val))
		return 0;
	return op_cpu_buffer_add_data(entry, (u32)(val >> 32));
}

int oprofile_write_commit(struct op_entry *entry)
{
	if (!entry->event)
		return -EINVAL;
	return op_cpu_buffer_write_commit(entry);
}

void oprofile_add_pc(unsigned long pc, int is_kernel, unsigned long event)
{
	struct oprofile_cpu_buffer *cpu_buf = this_cpu_ptr(&op_cpu_buffer);
	log_sample(cpu_buf, pc, 0, is_kernel, event, NULL);
}

void oprofile_add_trace(unsigned long pc)
{
	struct oprofile_cpu_buffer *cpu_buf = this_cpu_ptr(&op_cpu_buffer);

	if (!cpu_buf->tracing)
		return;

	/*
	 * broken frame can give an eip with the same value as an
	 * escape code, abort the trace if we get it
	 */
	if (pc == ESCAPE_CODE)
		goto fail;

	if (op_add_sample(cpu_buf, pc, 0))
		goto fail;

	return;
fail:
	cpu_buf->tracing = 0;
	cpu_buf->backtrace_aborted++;
	return;
}

/*
 * This serves to avoid cpu buffer overflow, and makes sure
 * the task mortuary progresses
 *
 * By using schedule_delayed_work_on and then schedule_delayed_work
 * we guarantee this will stay on the correct cpu
 */
static void wq_sync_buffer(struct work_struct *work)
{
	struct oprofile_cpu_buffer *b =
		container_of(work, struct oprofile_cpu_buffer, work.work);
	if (b->cpu != smp_processor_id() && !cpu_online(b->cpu)) {
		cancel_delayed_work(&b->work);
		return;
	}
	sync_buffer(b->cpu);

	/* don't re-add the work if we're shutting down */
	if (work_enabled)
		schedule_delayed_work(&b->work, DEFAULT_TIMER_EXPIRE);
}
Commit	Line	Data
1da177e4 LT	1	/**
	2	* @file cpu_buffer.c
	3	*
2cc28b9f	4	* @remark Copyright 2002-2009 OProfile authors
1da177e4 LT	5	* @remark Read the file COPYING
	6	*
	7	* @author John Levon <levon@movementarian.org>
345c2573	8	* @author Barry Kasindorf <barry.kasindorf@amd.com>
2cc28b9f	9	* @author Robert Richter <robert.richter@amd.com>
1da177e4 LT	10	*
	11	* Each CPU has a local buffer that stores PC value/event
	12	* pairs. We also log context switches when we notice them.
	13	* Eventually each CPU's buffer is processed into the global
	14	* event buffer by sync_buffer().
	15	*
	16	* We use a local buffer for two reasons: an NMI or similar
	17	* interrupt cannot synchronise, and high sampling rates
	18	* would lead to catastrophic global synchronisation if
	19	* a global buffer was used.
	20	*/
	21
	22	#include <linux/sched.h>
	23	#include <linux/oprofile.h>
1da177e4	24	#include <linux/errno.h>
6a18037d	25
4cf421e5 IM	26	#include <asm/ptrace.h>
4cf421e5 IM	27
1da177e4 LT	28	#include "event_buffer.h"
	29	#include "cpu_buffer.h"
	30	#include "buffer_sync.h"
	31	#include "oprof.h"
	32
6dad828b RR	33	#define OP_BUFFER_FLAGS 0
6dad828b RR	34
cb6e943c	35	static struct ring_buffer *op_ring_buffer;
b3e9f672	36	DEFINE_PER_CPU(struct oprofile_cpu_buffer, op_cpu_buffer);
1da177e4	37
c4028958	38	static void wq_sync_buffer(struct work_struct *work);
1da177e4 LT	39
	40	#define DEFAULT_TIMER_EXPIRE (HZ / 10)
	41	static int work_enabled;
	42
a5598ca0 CL	43	unsigned long oprofile_get_cpu_buffer_size(void)
a5598ca0 CL	44	{
bd2172f5	45	return oprofile_cpu_buffer_size;
a5598ca0 CL	46	}
	47
	48	void oprofile_cpu_buffer_inc_smpl_lost(void)
	49	{
879d9274	50	struct oprofile_cpu_buffer *cpu_buf = this_cpu_ptr(&op_cpu_buffer);
a5598ca0 CL	51
	52	cpu_buf->sample_lost_overflow++;
	53	}
	54
30015776 RR	55	void free_cpu_buffers(void)
30015776 RR	56	{
cb6e943c AK	57	if (op_ring_buffer)
	58	ring_buffer_free(op_ring_buffer);
	59	op_ring_buffer = NULL;
30015776 RR	60	}
30015776 RR	61
54f2c841 RR	62	#define RB_EVENT_HDR_SIZE 4
54f2c841 RR	63
1da177e4 LT	64	int alloc_cpu_buffers(void)
	65	{
	66	int i;
6a18037d	67
bd2172f5	68	unsigned long buffer_size = oprofile_cpu_buffer_size;
54f2c841 RR	69	unsigned long byte_size = buffer_size * (sizeof(struct op_sample) +
54f2c841 RR	70	RB_EVENT_HDR_SIZE);
6a18037d	71
cb6e943c AK	72	op_ring_buffer = ring_buffer_alloc(byte_size, OP_BUFFER_FLAGS);
cb6e943c AK	73	if (!op_ring_buffer)
6dad828b RR	74	goto fail;
6dad828b RR	75
4bd9b9dc	76	for_each_possible_cpu(i) {
b3e9f672	77	struct oprofile_cpu_buffer *b = &per_cpu(op_cpu_buffer, i);
6a18037d	78
1da177e4 LT	79	b->last_task = NULL;
	80	b->last_is_kernel = -1;
	81	b->tracing = 0;
	82	b->buffer_size = buffer_size;
1da177e4 LT	83	b->sample_received = 0;
1da177e4 LT	84	b->sample_lost_overflow = 0;
df9d177a PE	85	b->backtrace_aborted = 0;
df9d177a PE	86	b->sample_invalid_eip = 0;
1da177e4	87	b->cpu = i;
c4028958	88	INIT_DELAYED_WORK(&b->work, wq_sync_buffer);
1da177e4 LT	89	}
	90	return 0;
	91
	92	fail:
	93	free_cpu_buffers();
	94	return -ENOMEM;
	95	}
1da177e4 LT	96
	97	void start_cpu_work(void)
	98	{
	99	int i;
	100
	101	work_enabled = 1;
	102
	103	for_each_online_cpu(i) {
b3e9f672	104	struct oprofile_cpu_buffer *b = &per_cpu(op_cpu_buffer, i);
1da177e4 LT	105
	106	/*
	107	* Spread the work by 1 jiffy per cpu so they dont all
	108	* fire at once.
	109	*/
	110	schedule_delayed_work_on(i, &b->work, DEFAULT_TIMER_EXPIRE + i);
	111	}
	112	}
	113
1da177e4 LT	114	void end_cpu_work(void)
1da177e4 LT	115	{
1da177e4	116	work_enabled = 0;
3d7851b3 TH	117	}
	118
	119	void flush_cpu_work(void)
	120	{
	121	int i;
1da177e4 LT	122
1da177e4 LT	123	for_each_online_cpu(i) {
b3e9f672	124	struct oprofile_cpu_buffer *b = &per_cpu(op_cpu_buffer, i);
1da177e4	125
3d7851b3 TH	126	/* these works are per-cpu, no need for flush_sync */
3d7851b3 TH	127	flush_delayed_work(&b->work);
1da177e4	128	}
1da177e4 LT	129	}
1da177e4 LT	130
2cc28b9f RR	131	/*
	132	* This function prepares the cpu buffer to write a sample.
	133	*
	134	* Struct op_entry is used during operations on the ring buffer while
	135	* struct op_sample contains the data that is stored in the ring
	136	* buffer. Struct entry can be uninitialized. The function reserves a
	137	* data array that is specified by size. Use
	138	* op_cpu_buffer_write_commit() after preparing the sample. In case of
	139	* errors a null pointer is returned, otherwise the pointer to the
	140	* sample.
	141	*
	142	*/
	143	struct op_sample
	144	op_cpu_buffer_write_reserve(struct op_entry entry, unsigned long size)
9966718d	145	{
2cc28b9f	146	entry->event = ring_buffer_lock_reserve
cb6e943c	147	(op_ring_buffer, sizeof(struct op_sample) +
304cc6ae	148	size * sizeof(entry->sample->data[0]));
cb6e943c	149	if (!entry->event)
2cc28b9f	150	return NULL;
cb6e943c	151	entry->sample = ring_buffer_event_data(entry->event);
2cc28b9f RR	152	entry->size = size;
	153	entry->data = entry->sample->data;
	154
	155	return entry->sample;
9966718d RR	156	}
	157
	158	int op_cpu_buffer_write_commit(struct op_entry *entry)
	159	{
cb6e943c	160	return ring_buffer_unlock_commit(op_ring_buffer, entry->event);
9966718d RR	161	}
9966718d RR	162
2d87b14c	163	struct op_sample op_cpu_buffer_read_entry(struct op_entry entry, int cpu)
9966718d RR	164	{
9966718d RR	165	struct ring_buffer_event *e;
b971f061	166	e = ring_buffer_consume(op_ring_buffer, cpu, NULL, NULL);
cb6e943c	167	if (!e)
9966718d	168	return NULL;
2d87b14c	169
2d87b14c RR	170	entry->event = e;
	171	entry->sample = ring_buffer_event_data(e);
	172	entry->size = (ring_buffer_event_length(e) - sizeof(struct op_sample))
	173	/ sizeof(entry->sample->data[0]);
	174	entry->data = entry->sample->data;
	175	return entry->sample;
9966718d RR	176	}
	177
	178	unsigned long op_cpu_buffer_entries(int cpu)
	179	{
cb6e943c	180	return ring_buffer_entries_cpu(op_ring_buffer, cpu);
9966718d RR	181	}
9966718d RR	182
ae735e99 RR	183	static int
	184	op_add_code(struct oprofile_cpu_buffer *cpu_buf, unsigned long backtrace,
	185	int is_kernel, struct task_struct *task)
	186	{
	187	struct op_entry entry;
	188	struct op_sample *sample;
	189	unsigned long flags;
	190	int size;
	191
	192	flags = 0;
	193
	194	if (backtrace)
	195	flags \|= TRACE_BEGIN;
	196
	197	/* notice a switch from user->kernel or vice versa */
	198	is_kernel = !!is_kernel;
	199	if (cpu_buf->last_is_kernel != is_kernel) {
	200	cpu_buf->last_is_kernel = is_kernel;
	201	flags \|= KERNEL_CTX_SWITCH;
	202	if (is_kernel)
	203	flags \|= IS_KERNEL;
	204	}
	205
	206	/* notice a task switch */
	207	if (cpu_buf->last_task != task) {
	208	cpu_buf->last_task = task;
	209	flags \|= USER_CTX_SWITCH;
	210	}
	211
	212	if (!flags)
	213	/* nothing to do */
	214	return 0;
	215
	216	if (flags & USER_CTX_SWITCH)
	217	size = 1;
	218	else
	219	size = 0;
	220
	221	sample = op_cpu_buffer_write_reserve(&entry, size);
	222	if (!sample)
	223	return -ENOMEM;
	224
	225	sample->eip = ESCAPE_CODE;
	226	sample->event = flags;
	227
	228	if (size)
d9928c25	229	op_cpu_buffer_add_data(&entry, (unsigned long)task);
ae735e99 RR	230
	231	op_cpu_buffer_write_commit(&entry);
	232
	233	return 0;
	234	}
	235
211117ff	236	static inline int
d0e23384 RR	237	op_add_sample(struct oprofile_cpu_buffer *cpu_buf,
d0e23384 RR	238	unsigned long pc, unsigned long event)
1da177e4	239	{
6dad828b	240	struct op_entry entry;
2cc28b9f	241	struct op_sample *sample;
6dad828b	242
2cc28b9f RR	243	sample = op_cpu_buffer_write_reserve(&entry, 0);
	244	if (!sample)
	245	return -ENOMEM;
6dad828b	246
2cc28b9f RR	247	sample->eip = pc;
2cc28b9f RR	248	sample->event = event;
6dad828b	249
3967e93e	250	return op_cpu_buffer_write_commit(&entry);
1da177e4 LT	251	}
1da177e4 LT	252
ae735e99 RR	253	/*
ae735e99 RR	254	* This must be safe from any context.
1da177e4 LT	255	*
	256	* is_kernel is needed because on some architectures you cannot
	257	* tell if you are in kernel or user space simply by looking at
	258	* pc. We tag this in the buffer by generating kernel enter/exit
	259	* events whenever is_kernel changes
	260	*/
ae735e99 RR	261	static int
ae735e99 RR	262	log_sample(struct oprofile_cpu_buffer *cpu_buf, unsigned long pc,
54ebbe7b HG	263	unsigned long backtrace, int is_kernel, unsigned long event,
54ebbe7b HG	264	struct task_struct *task)
1da177e4	265	{
54ebbe7b	266	struct task_struct *tsk = task ? task : current;
1da177e4 LT	267	cpu_buf->sample_received++;
1da177e4 LT	268
df9d177a PE	269	if (pc == ESCAPE_CODE) {
	270	cpu_buf->sample_invalid_eip++;
	271	return 0;
	272	}
	273
54ebbe7b	274	if (op_add_code(cpu_buf, backtrace, is_kernel, tsk))
ae735e99	275	goto fail;
6a18037d	276
d0e23384	277	if (op_add_sample(cpu_buf, pc, event))
211117ff RR	278	goto fail;
211117ff RR	279
1da177e4	280	return 1;
211117ff RR	281
	282	fail:
	283	cpu_buf->sample_lost_overflow++;
	284	return 0;
1da177e4 LT	285	}
1da177e4 LT	286
6352d92d	287	static inline void oprofile_begin_trace(struct oprofile_cpu_buffer *cpu_buf)
1da177e4	288	{
1da177e4	289	cpu_buf->tracing = 1;
1da177e4 LT	290	}
1da177e4 LT	291
6352d92d	292	static inline void oprofile_end_trace(struct oprofile_cpu_buffer *cpu_buf)
1da177e4 LT	293	{
	294	cpu_buf->tracing = 0;
	295	}
	296
d45d23be RR	297	static inline void
d45d23be RR	298	__oprofile_add_ext_sample(unsigned long pc, struct pt_regs * const regs,
54ebbe7b HG	299	unsigned long event, int is_kernel,
54ebbe7b HG	300	struct task_struct *task)
1da177e4	301	{
879d9274	302	struct oprofile_cpu_buffer *cpu_buf = this_cpu_ptr(&op_cpu_buffer);
ae735e99	303	unsigned long backtrace = oprofile_backtrace_depth;
1da177e4	304
fd13f6c8 RR	305	/*
	306	* if log_sample() fail we can't backtrace since we lost the
	307	* source of this event
	308	*/
54ebbe7b	309	if (!log_sample(cpu_buf, pc, backtrace, is_kernel, event, task))
ae735e99 RR	310	/* failed */
	311	return;
	312
	313	if (!backtrace)
	314	return;
6352d92d	315
ae735e99 RR	316	oprofile_begin_trace(cpu_buf);
ae735e99 RR	317	oprofile_ops.backtrace(regs, backtrace);
1da177e4 LT	318	oprofile_end_trace(cpu_buf);
	319	}
	320
54ebbe7b HG	321	void oprofile_add_ext_hw_sample(unsigned long pc, struct pt_regs * const regs,
	322	unsigned long event, int is_kernel,
	323	struct task_struct *task)
	324	{
	325	__oprofile_add_ext_sample(pc, regs, event, is_kernel, task);
	326	}
	327
d45d23be RR	328	void oprofile_add_ext_sample(unsigned long pc, struct pt_regs * const regs,
	329	unsigned long event, int is_kernel)
	330	{
54ebbe7b	331	__oprofile_add_ext_sample(pc, regs, event, is_kernel, NULL);
d45d23be RR	332	}
d45d23be RR	333
27357716 BR	334	void oprofile_add_sample(struct pt_regs * const regs, unsigned long event)
27357716 BR	335	{
9414e996 PC	336	int is_kernel;
	337	unsigned long pc;
	338
	339	if (likely(regs)) {
	340	is_kernel = !user_mode(regs);
	341	pc = profile_pc(regs);
	342	} else {
	343	is_kernel = 0; /* This value will not be used */
	344	pc = ESCAPE_CODE; /* as this causes an early return. */
	345	}
27357716	346
54ebbe7b	347	__oprofile_add_ext_sample(pc, regs, event, is_kernel, NULL);
27357716 BR	348	}
27357716 BR	349
1acda878 RR	350	/*
	351	* Add samples with data to the ring buffer.
	352	*
14f0ca8e RR	353	* Use oprofile_add_data(&entry, val) to add data and
14f0ca8e RR	354	* oprofile_write_commit(&entry) to commit the sample.
1acda878	355	*/
14f0ca8e RR	356	void
14f0ca8e RR	357	oprofile_write_reserve(struct op_entry entry, struct pt_regs const regs,
1acda878	358	unsigned long pc, int code, int size)
345c2573	359	{
1acda878	360	struct op_sample *sample;
e2fee276	361	int is_kernel = !user_mode(regs);
879d9274	362	struct oprofile_cpu_buffer *cpu_buf = this_cpu_ptr(&op_cpu_buffer);
345c2573 BK	363
	364	cpu_buf->sample_received++;
	365
1acda878 RR	366	/* no backtraces for samples with data */
	367	if (op_add_code(cpu_buf, 0, is_kernel, current))
	368	goto fail;
	369
	370	sample = op_cpu_buffer_write_reserve(entry, size + 2);
	371	if (!sample)
	372	goto fail;
	373	sample->eip = ESCAPE_CODE;
	374	sample->event = 0; /* no flags */
345c2573	375
1acda878 RR	376	op_cpu_buffer_add_data(entry, code);
1acda878 RR	377	op_cpu_buffer_add_data(entry, pc);
345c2573	378
1acda878	379	return;
345c2573	380
1acda878	381	fail:
fdb6a8f4	382	entry->event = NULL;
1acda878	383	cpu_buf->sample_lost_overflow++;
345c2573 BK	384	}
345c2573 BK	385
14f0ca8e RR	386	int oprofile_add_data(struct op_entry *entry, unsigned long val)
14f0ca8e RR	387	{
fdb6a8f4 RR	388	if (!entry->event)
fdb6a8f4 RR	389	return 0;
14f0ca8e RR	390	return op_cpu_buffer_add_data(entry, val);
	391	}
	392
51563a0e RR	393	int oprofile_add_data64(struct op_entry *entry, u64 val)
	394	{
	395	if (!entry->event)
	396	return 0;
	397	if (op_cpu_buffer_get_size(entry) < 2)
	398	/*
	399	* the function returns 0 to indicate a too small
	400	* buffer, even if there is some space left
	401	*/
	402	return 0;
	403	if (!op_cpu_buffer_add_data(entry, (u32)val))
	404	return 0;
	405	return op_cpu_buffer_add_data(entry, (u32)(val >> 32));
	406	}
	407
14f0ca8e RR	408	int oprofile_write_commit(struct op_entry *entry)
14f0ca8e RR	409	{
fdb6a8f4 RR	410	if (!entry->event)
fdb6a8f4 RR	411	return -EINVAL;
14f0ca8e RR	412	return op_cpu_buffer_write_commit(entry);
	413	}
	414
1da177e4 LT	415	void oprofile_add_pc(unsigned long pc, int is_kernel, unsigned long event)
1da177e4 LT	416	{
879d9274	417	struct oprofile_cpu_buffer *cpu_buf = this_cpu_ptr(&op_cpu_buffer);
54ebbe7b	418	log_sample(cpu_buf, pc, 0, is_kernel, event, NULL);
1da177e4 LT	419	}
1da177e4 LT	420
1da177e4 LT	421	void oprofile_add_trace(unsigned long pc)
1da177e4 LT	422	{
879d9274	423	struct oprofile_cpu_buffer *cpu_buf = this_cpu_ptr(&op_cpu_buffer);
1da177e4 LT	424
	425	if (!cpu_buf->tracing)
	426	return;
	427
fd13f6c8 RR	428	/*
	429	* broken frame can give an eip with the same value as an
	430	* escape code, abort the trace if we get it
	431	*/
211117ff RR	432	if (pc == ESCAPE_CODE)
	433	goto fail;
	434
d0e23384	435	if (op_add_sample(cpu_buf, pc, 0))
211117ff	436	goto fail;
1da177e4	437
211117ff RR	438	return;
	439	fail:
	440	cpu_buf->tracing = 0;
	441	cpu_buf->backtrace_aborted++;
	442	return;
1da177e4 LT	443	}
1da177e4 LT	444
1da177e4 LT	445	/*
	446	* This serves to avoid cpu buffer overflow, and makes sure
	447	* the task mortuary progresses
	448	*
	449	* By using schedule_delayed_work_on and then schedule_delayed_work
	450	* we guarantee this will stay on the correct cpu
	451	*/
c4028958	452	static void wq_sync_buffer(struct work_struct *work)
1da177e4	453	{
25ad2913	454	struct oprofile_cpu_buffer *b =
c4028958	455	container_of(work, struct oprofile_cpu_buffer, work.work);
61bccf19 RR	456	if (b->cpu != smp_processor_id() && !cpu_online(b->cpu)) {
	457	cancel_delayed_work(&b->work);
	458	return;
1da177e4 LT	459	}
	460	sync_buffer(b->cpu);
	461
	462	/* don't re-add the work if we're shutting down */
	463	if (work_enabled)
	464	schedule_delayed_work(&b->work, DEFAULT_TIMER_EXPIRE);
	465	}