[net-next-2.6.git] / arch / arm / oprofile / common.c

/**
 * @file common.c
 *
 * @remark Copyright 2004 Oprofile Authors
 * @remark Copyright 2010 ARM Ltd.
 * @remark Read the file COPYING
 *
 * @author Zwane Mwaikambo
 * @author Will Deacon [move to perf]
 */

#include <linux/cpumask.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/oprofile.h>
#include <linux/perf_event.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <asm/stacktrace.h>
#include <linux/uaccess.h>

#include <asm/perf_event.h>
#include <asm/ptrace.h>

#ifdef CONFIG_HW_PERF_EVENTS
/*
 * Per performance monitor configuration as set via oprofilefs.
 */
struct op_counter_config {
	unsigned long count;
	unsigned long enabled;
	unsigned long event;
	unsigned long unit_mask;
	unsigned long kernel;
	unsigned long user;
	struct perf_event_attr attr;
};

static int op_arm_enabled;
static DEFINE_MUTEX(op_arm_mutex);

static struct op_counter_config *counter_config;
static struct perf_event **perf_events[nr_cpumask_bits];
static int perf_num_counters;

/*
 * Overflow callback for oprofile.
 */
static void op_overflow_handler(struct perf_event *event, int unused,
			struct perf_sample_data *data, struct pt_regs *regs)
{
	int id;
	u32 cpu = smp_processor_id();

	for (id = 0; id < perf_num_counters; ++id)
		if (perf_events[cpu][id] == event)
			break;

	if (id != perf_num_counters)
		oprofile_add_sample(regs, id);
	else
		pr_warning("oprofile: ignoring spurious overflow "
				"on cpu %u\n", cpu);
}

/*
 * Called by op_arm_setup to create perf attributes to mirror the oprofile
 * settings in counter_config. Attributes are created as `pinned' events and
 * so are permanently scheduled on the PMU.
 */
static void op_perf_setup(void)
{
	int i;
	u32 size = sizeof(struct perf_event_attr);
	struct perf_event_attr *attr;

	for (i = 0; i < perf_num_counters; ++i) {
		attr = &counter_config[i].attr;
		memset(attr, 0, size);
		attr->type		= PERF_TYPE_RAW;
		attr->size		= size;
		attr->config		= counter_config[i].event;
		attr->sample_period	= counter_config[i].count;
		attr->pinned		= 1;
	}
}

static int op_create_counter(int cpu, int event)
{
	int ret = 0;
	struct perf_event *pevent;

	if (!counter_config[event].enabled || (perf_events[cpu][event] != NULL))
		return ret;

	pevent = perf_event_create_kernel_counter(&counter_config[event].attr,
						  cpu, -1,
						  op_overflow_handler);

	if (IS_ERR(pevent)) {
		ret = PTR_ERR(pevent);
	} else if (pevent->state != PERF_EVENT_STATE_ACTIVE) {
		perf_event_release_kernel(pevent);
		pr_warning("oprofile: failed to enable event %d "
				"on CPU %d\n", event, cpu);
		ret = -EBUSY;
	} else {
		perf_events[cpu][event] = pevent;
	}

	return ret;
}

static void op_destroy_counter(int cpu, int event)
{
	struct perf_event *pevent = perf_events[cpu][event];

	if (pevent) {
		perf_event_release_kernel(pevent);
		perf_events[cpu][event] = NULL;
	}
}

/*
 * Called by op_arm_start to create active perf events based on the
 * perviously configured attributes.
 */
static int op_perf_start(void)
{
	int cpu, event, ret = 0;

	for_each_online_cpu(cpu) {
		for (event = 0; event < perf_num_counters; ++event) {
			ret = op_create_counter(cpu, event);
			if (ret)
				goto out;
		}
	}

out:
	return ret;
}

/*
 * Called by op_arm_stop at the end of a profiling run.
 */
static void op_perf_stop(void)
{
	int cpu, event;

	for_each_online_cpu(cpu)
		for (event = 0; event < perf_num_counters; ++event)
			op_destroy_counter(cpu, event);
}


static char *op_name_from_perf_id(enum arm_perf_pmu_ids id)
{
	switch (id) {
	case ARM_PERF_PMU_ID_XSCALE1:
		return "arm/xscale1";
	case ARM_PERF_PMU_ID_XSCALE2:
		return "arm/xscale2";
	case ARM_PERF_PMU_ID_V6:
		return "arm/armv6";
	case ARM_PERF_PMU_ID_V6MP:
		return "arm/mpcore";
	case ARM_PERF_PMU_ID_CA8:
		return "arm/armv7";
	case ARM_PERF_PMU_ID_CA9:
		return "arm/armv7-ca9";
	default:
		return NULL;
	}
}

static int op_arm_create_files(struct super_block *sb, struct dentry *root)
{
	unsigned int i;

	for (i = 0; i < perf_num_counters; i++) {
		struct dentry *dir;
		char buf[4];

		snprintf(buf, sizeof buf, "%d", i);
		dir = oprofilefs_mkdir(sb, root, buf);
		oprofilefs_create_ulong(sb, dir, "enabled", &counter_config[i].enabled);
		oprofilefs_create_ulong(sb, dir, "event", &counter_config[i].event);
		oprofilefs_create_ulong(sb, dir, "count", &counter_config[i].count);
		oprofilefs_create_ulong(sb, dir, "unit_mask", &counter_config[i].unit_mask);
		oprofilefs_create_ulong(sb, dir, "kernel", &counter_config[i].kernel);
		oprofilefs_create_ulong(sb, dir, "user", &counter_config[i].user);
	}

	return 0;
}

static int op_arm_setup(void)
{
	spin_lock(&oprofilefs_lock);
	op_perf_setup();
	spin_unlock(&oprofilefs_lock);
	return 0;
}

static int op_arm_start(void)
{
	int ret = -EBUSY;

	mutex_lock(&op_arm_mutex);
	if (!op_arm_enabled) {
		ret = 0;
		op_perf_start();
		op_arm_enabled = 1;
	}
	mutex_unlock(&op_arm_mutex);
	return ret;
}

static void op_arm_stop(void)
{
	mutex_lock(&op_arm_mutex);
	if (op_arm_enabled)
		op_perf_stop();
	op_arm_enabled = 0;
	mutex_unlock(&op_arm_mutex);
}

#ifdef CONFIG_PM
static int op_arm_suspend(struct platform_device *dev, pm_message_t state)
{
	mutex_lock(&op_arm_mutex);
	if (op_arm_enabled)
		op_perf_stop();
	mutex_unlock(&op_arm_mutex);
	return 0;
}

static int op_arm_resume(struct platform_device *dev)
{
	mutex_lock(&op_arm_mutex);
	if (op_arm_enabled && op_perf_start())
		op_arm_enabled = 0;
	mutex_unlock(&op_arm_mutex);
	return 0;
}

static struct platform_driver oprofile_driver = {
	.driver		= {
		.name		= "arm-oprofile",
	},
	.resume		= op_arm_resume,
	.suspend	= op_arm_suspend,
};

static struct platform_device *oprofile_pdev;

static int __init init_driverfs(void)
{
	int ret;

	ret = platform_driver_register(&oprofile_driver);
	if (ret)
		goto out;

	oprofile_pdev =	platform_device_register_simple(
				oprofile_driver.driver.name, 0, NULL, 0);
	if (IS_ERR(oprofile_pdev)) {
		ret = PTR_ERR(oprofile_pdev);
		platform_driver_unregister(&oprofile_driver);
	}

out:
	return ret;
}

static void  exit_driverfs(void)
{
	platform_device_unregister(oprofile_pdev);
	platform_driver_unregister(&oprofile_driver);
}
#else
static int __init init_driverfs(void) { return 0; }
#define exit_driverfs() do { } while (0)
#endif /* CONFIG_PM */

static int report_trace(struct stackframe *frame, void *d)
{
	unsigned int *depth = d;

	if (*depth) {
		oprofile_add_trace(frame->pc);
		(*depth)--;
	}

	return *depth == 0;
}

/*
 * The registers we're interested in are at the end of the variable
 * length saved register structure. The fp points at the end of this
 * structure so the address of this struct is:
 * (struct frame_tail *)(xxx->fp)-1
 */
struct frame_tail {
	struct frame_tail *fp;
	unsigned long sp;
	unsigned long lr;
} __attribute__((packed));

static struct frame_tail* user_backtrace(struct frame_tail *tail)
{
	struct frame_tail buftail[2];

	/* Also check accessibility of one struct frame_tail beyond */
	if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
		return NULL;
	if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail)))
		return NULL;

	oprofile_add_trace(buftail[0].lr);

	/* frame pointers should strictly progress back up the stack
	 * (towards higher addresses) */
	if (tail >= buftail[0].fp)
		return NULL;

	return buftail[0].fp-1;
}

static void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
{
	struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;

	if (!user_mode(regs)) {
		struct stackframe frame;
		frame.fp = regs->ARM_fp;
		frame.sp = regs->ARM_sp;
		frame.lr = regs->ARM_lr;
		frame.pc = regs->ARM_pc;
		walk_stackframe(&frame, report_trace, &depth);
		return;
	}

	while (depth-- && tail && !((unsigned long) tail & 3))
		tail = user_backtrace(tail);
}

int __init oprofile_arch_init(struct oprofile_operations *ops)
{
	int cpu, ret = 0;

	perf_num_counters = armpmu_get_max_events();

	counter_config = kcalloc(perf_num_counters,
			sizeof(struct op_counter_config), GFP_KERNEL);

	if (!counter_config) {
		pr_info("oprofile: failed to allocate %d "
				"counters\n", perf_num_counters);
		return -ENOMEM;
	}

	ret = init_driverfs();
	if (ret) {
		kfree(counter_config);
		counter_config = NULL;
		return ret;
	}

	for_each_possible_cpu(cpu) {
		perf_events[cpu] = kcalloc(perf_num_counters,
				sizeof(struct perf_event *), GFP_KERNEL);
		if (!perf_events[cpu]) {
			pr_info("oprofile: failed to allocate %d perf events "
					"for cpu %d\n", perf_num_counters, cpu);
			while (--cpu >= 0)
				kfree(perf_events[cpu]);
			return -ENOMEM;
		}
	}

	ops->backtrace		= arm_backtrace;
	ops->create_files	= op_arm_create_files;
	ops->setup		= op_arm_setup;
	ops->start		= op_arm_start;
	ops->stop		= op_arm_stop;
	ops->shutdown		= op_arm_stop;
	ops->cpu_type		= op_name_from_perf_id(armpmu_get_pmu_id());

	if (!ops->cpu_type)
		ret = -ENODEV;
	else
		pr_info("oprofile: using %s\n", ops->cpu_type);

	return ret;
}

void oprofile_arch_exit(void)
{
	int cpu, id;
	struct perf_event *event;

	if (*perf_events) {
		for_each_possible_cpu(cpu) {
			for (id = 0; id < perf_num_counters; ++id) {
				event = perf_events[cpu][id];
				if (event != NULL)
					perf_event_release_kernel(event);
			}
			kfree(perf_events[cpu]);
		}
	}

	if (counter_config) {
		kfree(counter_config);
		exit_driverfs();
	}
}
#else
int __init oprofile_arch_init(struct oprofile_operations *ops)
{
	pr_info("oprofile: hardware counters not available\n");
	return -ENODEV;
}
void oprofile_arch_exit(void) {}
#endif /* CONFIG_HW_PERF_EVENTS */
Commit	Line	Data
1da177e4 LT	1	/**
	2	* @file common.c
	3	*
	4	* @remark Copyright 2004 Oprofile Authors
8c1fc96f	5	* @remark Copyright 2010 ARM Ltd.
1da177e4 LT	6	* @remark Read the file COPYING
	7	*
	8	* @author Zwane Mwaikambo
8c1fc96f	9	* @author Will Deacon [move to perf]
1da177e4 LT	10	*/
1da177e4 LT	11
8c1fc96f	12	#include <linux/cpumask.h>
d1e86d64	13	#include <linux/err.h>
8c1fc96f	14	#include <linux/errno.h>
1da177e4	15	#include <linux/init.h>
8c1fc96f	16	#include <linux/mutex.h>
1da177e4	17	#include <linux/oprofile.h>
8c1fc96f	18	#include <linux/perf_event.h>
d1e86d64	19	#include <linux/platform_device.h>
ae92dc9f	20	#include <linux/slab.h>
8c1fc96f WD	21	#include <asm/stacktrace.h>
	22	#include <linux/uaccess.h>
	23
	24	#include <asm/perf_event.h>
	25	#include <asm/ptrace.h>
1da177e4	26
8c1fc96f WD	27	#ifdef CONFIG_HW_PERF_EVENTS
	28	/*
	29	* Per performance monitor configuration as set via oprofilefs.
	30	*/
	31	struct op_counter_config {
	32	unsigned long count;
	33	unsigned long enabled;
	34	unsigned long event;
	35	unsigned long unit_mask;
	36	unsigned long kernel;
	37	unsigned long user;
	38	struct perf_event_attr attr;
	39	};
1da177e4	40
55f05234	41	static int op_arm_enabled;
93ad7949	42	static DEFINE_MUTEX(op_arm_mutex);
1da177e4	43
8c1fc96f WD	44	static struct op_counter_config *counter_config;
	45	static struct perf_event **perf_events[nr_cpumask_bits];
	46	static int perf_num_counters;
	47
	48	/*
	49	* Overflow callback for oprofile.
	50	*/
	51	static void op_overflow_handler(struct perf_event *event, int unused,
	52	struct perf_sample_data data, struct pt_regs regs)
	53	{
	54	int id;
	55	u32 cpu = smp_processor_id();
	56
	57	for (id = 0; id < perf_num_counters; ++id)
	58	if (perf_events[cpu][id] == event)
	59	break;
	60
	61	if (id != perf_num_counters)
	62	oprofile_add_sample(regs, id);
	63	else
	64	pr_warning("oprofile: ignoring spurious overflow "
	65	"on cpu %u\n", cpu);
	66	}
	67
	68	/*
	69	* Called by op_arm_setup to create perf attributes to mirror the oprofile
	70	* settings in counter_config. Attributes are created as `pinned' events and
	71	* so are permanently scheduled on the PMU.
	72	*/
	73	static void op_perf_setup(void)
	74	{
	75	int i;
	76	u32 size = sizeof(struct perf_event_attr);
	77	struct perf_event_attr *attr;
	78
	79	for (i = 0; i < perf_num_counters; ++i) {
	80	attr = &counter_config[i].attr;
	81	memset(attr, 0, size);
	82	attr->type = PERF_TYPE_RAW;
	83	attr->size = size;
	84	attr->config = counter_config[i].event;
	85	attr->sample_period = counter_config[i].count;
	86	attr->pinned = 1;
	87	}
	88	}
	89
	90	static int op_create_counter(int cpu, int event)
	91	{
	92	int ret = 0;
	93	struct perf_event *pevent;
	94
	95	if (!counter_config[event].enabled \|\| (perf_events[cpu][event] != NULL))
	96	return ret;
	97
	98	pevent = perf_event_create_kernel_counter(&counter_config[event].attr,
	99	cpu, -1,
	100	op_overflow_handler);
	101
	102	if (IS_ERR(pevent)) {
	103	ret = PTR_ERR(pevent);
	104	} else if (pevent->state != PERF_EVENT_STATE_ACTIVE) {
98d943b0	105	perf_event_release_kernel(pevent);
8c1fc96f WD	106	pr_warning("oprofile: failed to enable event %d "
	107	"on CPU %d\n", event, cpu);
	108	ret = -EBUSY;
	109	} else {
	110	perf_events[cpu][event] = pevent;
	111	}
	112
	113	return ret;
	114	}
	115
	116	static void op_destroy_counter(int cpu, int event)
	117	{
	118	struct perf_event *pevent = perf_events[cpu][event];
	119
	120	if (pevent) {
	121	perf_event_release_kernel(pevent);
	122	perf_events[cpu][event] = NULL;
	123	}
	124	}
	125
	126	/*
	127	* Called by op_arm_start to create active perf events based on the
	128	* perviously configured attributes.
	129	*/
	130	static int op_perf_start(void)
	131	{
	132	int cpu, event, ret = 0;
	133
	134	for_each_online_cpu(cpu) {
	135	for (event = 0; event < perf_num_counters; ++event) {
	136	ret = op_create_counter(cpu, event);
	137	if (ret)
	138	goto out;
	139	}
	140	}
	141
	142	out:
	143	return ret;
	144	}
	145
	146	/*
	147	* Called by op_arm_stop at the end of a profiling run.
	148	*/
	149	static void op_perf_stop(void)
	150	{
	151	int cpu, event;
	152
	153	for_each_online_cpu(cpu)
	154	for (event = 0; event < perf_num_counters; ++event)
	155	op_destroy_counter(cpu, event);
	156	}
	157
	158
	159	static char *op_name_from_perf_id(enum arm_perf_pmu_ids id)
	160	{
	161	switch (id) {
	162	case ARM_PERF_PMU_ID_XSCALE1:
	163	return "arm/xscale1";
	164	case ARM_PERF_PMU_ID_XSCALE2:
	165	return "arm/xscale2";
	166	case ARM_PERF_PMU_ID_V6:
	167	return "arm/armv6";
	168	case ARM_PERF_PMU_ID_V6MP:
	169	return "arm/mpcore";
170	case ARM_PERF_PMU_ID_CA8:
171	return "arm/armv7";
172	case ARM_PERF_PMU_ID_CA9:
173	return "arm/armv7-ca9";
174	default:
175	return NULL;
176	}
177	}
1da177e4	178
55f05234	179	static int op_arm_create_files(struct super_block sb, struct dentry root)
1da177e4 LT	180	{
	181	unsigned int i;
	182
8c1fc96f	183	for (i = 0; i < perf_num_counters; i++) {
1da177e4	184	struct dentry *dir;
ae92dc9f	185	char buf[4];
1da177e4 LT	186
	187	snprintf(buf, sizeof buf, "%d", i);
	188	dir = oprofilefs_mkdir(sb, root, buf);
	189	oprofilefs_create_ulong(sb, dir, "enabled", &counter_config[i].enabled);
	190	oprofilefs_create_ulong(sb, dir, "event", &counter_config[i].event);
	191	oprofilefs_create_ulong(sb, dir, "count", &counter_config[i].count);
	192	oprofilefs_create_ulong(sb, dir, "unit_mask", &counter_config[i].unit_mask);
	193	oprofilefs_create_ulong(sb, dir, "kernel", &counter_config[i].kernel);
	194	oprofilefs_create_ulong(sb, dir, "user", &counter_config[i].user);
	195	}
	196
	197	return 0;
	198	}
	199
55f05234	200	static int op_arm_setup(void)
1da177e4	201	{
1da177e4	202	spin_lock(&oprofilefs_lock);
8c1fc96f	203	op_perf_setup();
1da177e4	204	spin_unlock(&oprofilefs_lock);
8c1fc96f	205	return 0;
1da177e4 LT	206	}
1da177e4 LT	207
55f05234	208	static int op_arm_start(void)
1da177e4 LT	209	{
	210	int ret = -EBUSY;
	211
93ad7949	212	mutex_lock(&op_arm_mutex);
55f05234	213	if (!op_arm_enabled) {
8c1fc96f WD	214	ret = 0;
	215	op_perf_start();
	216	op_arm_enabled = 1;
1da177e4	217	}
93ad7949	218	mutex_unlock(&op_arm_mutex);
1da177e4 LT	219	return ret;
	220	}
	221
55f05234	222	static void op_arm_stop(void)
1da177e4	223	{
93ad7949	224	mutex_lock(&op_arm_mutex);
55f05234	225	if (op_arm_enabled)
8c1fc96f	226	op_perf_stop();
55f05234	227	op_arm_enabled = 0;
93ad7949	228	mutex_unlock(&op_arm_mutex);
1da177e4 LT	229	}
1da177e4 LT	230
b5893c56	231	#ifdef CONFIG_PM
d1e86d64	232	static int op_arm_suspend(struct platform_device *dev, pm_message_t state)
b5893c56	233	{
93ad7949	234	mutex_lock(&op_arm_mutex);
55f05234	235	if (op_arm_enabled)
8c1fc96f	236	op_perf_stop();
93ad7949	237	mutex_unlock(&op_arm_mutex);
b5893c56 RK	238	return 0;
	239	}
	240
d1e86d64	241	static int op_arm_resume(struct platform_device *dev)
b5893c56	242	{
93ad7949	243	mutex_lock(&op_arm_mutex);
8c1fc96f	244	if (op_arm_enabled && op_perf_start())
55f05234	245	op_arm_enabled = 0;
93ad7949	246	mutex_unlock(&op_arm_mutex);
b5893c56 RK	247	return 0;
	248	}
	249
d1e86d64 WD	250	static struct platform_driver oprofile_driver = {
	251	.driver = {
	252	.name = "arm-oprofile",
	253	},
55f05234 RK	254	.resume = op_arm_resume,
55f05234 RK	255	.suspend = op_arm_suspend,
b5893c56 RK	256	};
b5893c56 RK	257
d1e86d64	258	static struct platform_device *oprofile_pdev;
b5893c56 RK	259
	260	static int __init init_driverfs(void)
	261	{
	262	int ret;
	263
d1e86d64 WD	264	ret = platform_driver_register(&oprofile_driver);
	265	if (ret)
	266	goto out;
	267
	268	oprofile_pdev = platform_device_register_simple(
	269	oprofile_driver.driver.name, 0, NULL, 0);
	270	if (IS_ERR(oprofile_pdev)) {
	271	ret = PTR_ERR(oprofile_pdev);
	272	platform_driver_unregister(&oprofile_driver);
	273	}
b5893c56	274
d1e86d64	275	out:
b5893c56 RK	276	return ret;
	277	}
	278
	279	static void exit_driverfs(void)
	280	{
d1e86d64 WD	281	platform_device_unregister(oprofile_pdev);
d1e86d64 WD	282	platform_driver_unregister(&oprofile_driver);
b5893c56 RK	283	}
b5893c56 RK	284	#else
d1e86d64	285	static int __init init_driverfs(void) { return 0; }
b5893c56 RK	286	#define exit_driverfs() do { } while (0)
	287	#endif /* CONFIG_PM */
	288
8c1fc96f	289	static int report_trace(struct stackframe frame, void d)
1da177e4	290	{
8c1fc96f	291	unsigned int *depth = d;
c6b9dafc	292
8c1fc96f WD	293	if (*depth) {
	294	oprofile_add_trace(frame->pc);
	295	(*depth)--;
	296	}
1b7b5698	297
8c1fc96f WD	298	return *depth == 0;
8c1fc96f WD	299	}
c6b9dafc	300
8c1fc96f WD	301	/*
	302	* The registers we're interested in are at the end of the variable
	303	* length saved register structure. The fp points at the end of this
	304	* structure so the address of this struct is:
	305	* (struct frame_tail *)(xxx->fp)-1
	306	*/
	307	struct frame_tail {
	308	struct frame_tail *fp;
	309	unsigned long sp;
	310	unsigned long lr;
	311	} __attribute__((packed));
2d9e1ae0	312
8c1fc96f WD	313	static struct frame_tail* user_backtrace(struct frame_tail *tail)
	314	{
	315	struct frame_tail buftail[2];
10c03f69	316
8c1fc96f WD	317	/* Also check accessibility of one struct frame_tail beyond */
	318	if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
	319	return NULL;
	320	if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail)))
	321	return NULL;
d7ac4e28	322
8c1fc96f	323	oprofile_add_trace(buftail[0].lr);
c6b9dafc	324
8c1fc96f WD	325	/* frame pointers should strictly progress back up the stack
	326	* (towards higher addresses) */
	327	if (tail >= buftail[0].fp)
	328	return NULL;
	329
	330	return buftail[0].fp-1;
	331	}
	332
	333	static void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
	334	{
	335	struct frame_tail tail = ((struct frame_tail ) regs->ARM_fp) - 1;
	336
	337	if (!user_mode(regs)) {
	338	struct stackframe frame;
	339	frame.fp = regs->ARM_fp;
	340	frame.sp = regs->ARM_sp;
	341	frame.lr = regs->ARM_lr;
	342	frame.pc = regs->ARM_pc;
	343	walk_stackframe(&frame, report_trace, &depth);
	344	return;
	345	}
	346
	347	while (depth-- && tail && !((unsigned long) tail & 3))
	348	tail = user_backtrace(tail);
	349	}
	350
	351	int __init oprofile_arch_init(struct oprofile_operations *ops)
	352	{
	353	int cpu, ret = 0;
	354
	355	perf_num_counters = armpmu_get_max_events();
	356
	357	counter_config = kcalloc(perf_num_counters,
	358	sizeof(struct op_counter_config), GFP_KERNEL);
ae92dc9f	359
8c1fc96f WD	360	if (!counter_config) {
	361	pr_info("oprofile: failed to allocate %d "
	362	"counters\n", perf_num_counters);
	363	return -ENOMEM;
c6b9dafc	364	}
1da177e4	365
d1e86d64 WD	366	ret = init_driverfs();
	367	if (ret) {
	368	kfree(counter_config);
98d943b0	369	counter_config = NULL;
d1e86d64 WD	370	return ret;
	371	}
	372
8c1fc96f WD	373	for_each_possible_cpu(cpu) {
	374	perf_events[cpu] = kcalloc(perf_num_counters,
	375	sizeof(struct perf_event *), GFP_KERNEL);
	376	if (!perf_events[cpu]) {
	377	pr_info("oprofile: failed to allocate %d perf events "
	378	"for cpu %d\n", perf_num_counters, cpu);
	379	while (--cpu >= 0)
	380	kfree(perf_events[cpu]);
	381	return -ENOMEM;
	382	}
	383	}
	384
8c1fc96f WD	385	ops->backtrace = arm_backtrace;
	386	ops->create_files = op_arm_create_files;
	387	ops->setup = op_arm_setup;
	388	ops->start = op_arm_start;
	389	ops->stop = op_arm_stop;
	390	ops->shutdown = op_arm_stop;
	391	ops->cpu_type = op_name_from_perf_id(armpmu_get_pmu_id());
	392
	393	if (!ops->cpu_type)
	394	ret = -ENODEV;
	395	else
	396	pr_info("oprofile: using %s\n", ops->cpu_type);
	397
c6b9dafc	398	return ret;
1da177e4 LT	399	}
1da177e4 LT	400
c6b9dafc	401	void oprofile_arch_exit(void)
1da177e4	402	{
8c1fc96f WD	403	int cpu, id;
	404	struct perf_event *event;
	405
	406	if (*perf_events) {
8c1fc96f WD	407	for_each_possible_cpu(cpu) {
	408	for (id = 0; id < perf_num_counters; ++id) {
	409	event = perf_events[cpu][id];
	410	if (event != NULL)
	411	perf_event_release_kernel(event);
	412	}
	413	kfree(perf_events[cpu]);
	414	}
1da177e4	415	}
8c1fc96f	416
98d943b0	417	if (counter_config) {
8c1fc96f	418	kfree(counter_config);
98d943b0 RR	419	exit_driverfs();
98d943b0 RR	420	}
8c1fc96f WD	421	}
	422	#else
	423	int __init oprofile_arch_init(struct oprofile_operations *ops)
	424	{
	425	pr_info("oprofile: hardware counters not available\n");
	426	return -ENODEV;
1da177e4	427	}
8c1fc96f WD	428	void oprofile_arch_exit(void) {}
8c1fc96f WD	429	#endif /* CONFIG_HW_PERF_EVENTS */