aboutsummaryrefslogtreecommitdiff
path: root/drivers/oprofile/oprofile_perf.c
blob: 59acf9ef78a42a33870300c307ef97a70b3dc087 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
/*
 * Copyright 2010 ARM Ltd.
 *
 * Perf-events backend for OProfile.
 */
#include <linux/perf_event.h>
#include <linux/platform_device.h>
#include <linux/oprofile.h>
#include <linux/slab.h>

/*
 * 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 oprofile_perf_enabled;
static DEFINE_MUTEX(oprofile_perf_mutex);

static struct op_counter_config *counter_config;
static struct perf_event **perf_events[nr_cpumask_bits];
static int 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 < num_counters; ++id)
		if (perf_events[cpu][id] == event)
			break;

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

/*
 * Called by oprofile_perf_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 < 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)
{
	struct perf_event *pevent;

	if (!counter_config[event].enabled || perf_events[cpu][event])
		return 0;

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

	if (IS_ERR(pevent))
		return PTR_ERR(pevent);

	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);
		return -EBUSY;
	}

	perf_events[cpu][event] = pevent;

	return 0;
}

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 oprofile_perf_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 < num_counters; ++event) {
			ret = op_create_counter(cpu, event);
			if (ret)
				return ret;
		}
	}

	return ret;
}

/*
 * Called by oprofile_perf_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 < num_counters; ++event)
			op_destroy_counter(cpu, event);
}

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

	for (i = 0; i < 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 oprofile_perf_setup(void)
{
	spin_lock(&oprofilefs_lock);
	op_perf_setup();
	spin_unlock(&oprofilefs_lock);
	return 0;
}

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

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

static void oprofile_perf_stop(void)
{
	mutex_lock(&oprofile_perf_mutex);
	if (oprofile_perf_enabled)
		op_perf_stop();
	oprofile_perf_enabled = 0;
	mutex_unlock(&oprofile_perf_mutex);
}

#ifdef CONFIG_PM

static int oprofile_perf_suspend(struct platform_device *dev, pm_message_t state)
{
	mutex_lock(&oprofile_perf_mutex);
	if (oprofile_perf_enabled)
		op_perf_stop();
	mutex_unlock(&oprofile_perf_mutex);
	return 0;
}

static int oprofile_perf_resume(struct platform_device *dev)
{
	mutex_lock(&oprofile_perf_mutex);
	if (oprofile_perf_enabled && op_perf_start())
		oprofile_perf_enabled = 0;
	mutex_unlock(&oprofile_perf_mutex);
	return 0;
}

static struct platform_driver oprofile_driver = {
	.driver		= {
		.name		= "oprofile-perf",
	},
	.resume		= oprofile_perf_resume,
	.suspend	= oprofile_perf_suspend,
};

static struct platform_device *oprofile_pdev;

static int __init init_driverfs(void)
{
	int ret;

	ret = platform_driver_register(&oprofile_driver);
	if (ret)
		return ret;

	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);
	}

	return ret;
}

static void exit_driverfs(void)
{
	platform_device_unregister(oprofile_pdev);
	platform_driver_unregister(&oprofile_driver);
}

#else

static inline int  init_driverfs(void) { return 0; }
static inline void exit_driverfs(void) { }

#endif /* CONFIG_PM */

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

	for_each_possible_cpu(cpu) {
		for (id = 0; id < num_counters; ++id) {
			event = perf_events[cpu][id];
			if (event)
				perf_event_release_kernel(event);
		}

		kfree(perf_events[cpu]);
	}

	kfree(counter_config);
	exit_driverfs();
}

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

	ret = init_driverfs();
	if (ret)
		return ret;

	memset(&perf_events, 0, sizeof(perf_events));

	num_counters = perf_num_counters();
	if (num_counters <= 0) {
		pr_info("oprofile: no performance counters\n");
		ret = -ENODEV;
		goto out;
	}

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

	if (!counter_config) {
		pr_info("oprofile: failed to allocate %d "
				"counters\n", num_counters);
		ret = -ENOMEM;
		num_counters = 0;
		goto out;
	}

	for_each_possible_cpu(cpu) {
		perf_events[cpu] = kcalloc(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", num_counters, cpu);
			ret = -ENOMEM;
			goto out;
		}
	}

	ops->create_files	= oprofile_perf_create_files;
	ops->setup		= oprofile_perf_setup;
	ops->start		= oprofile_perf_start;
	ops->stop		= oprofile_perf_stop;
	ops->shutdown		= oprofile_perf_stop;
	ops->cpu_type		= op_name_from_perf_id();

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

out:
	if (ret)
		oprofile_perf_exit();

	return ret;
}