8718311cb530ccfd237ec39a062f2951dba44601
[linux-3.10.git] / arch / arm / oprofile / common.c
1 /**
2  * @file common.c
3  *
4  * @remark Copyright 2004 Oprofile Authors
5  * @remark Copyright 2010 ARM Ltd.
6  * @remark Read the file COPYING
7  *
8  * @author Zwane Mwaikambo
9  * @author Will Deacon [move to perf]
10  */
11
12 #include <linux/cpumask.h>
13 #include <linux/err.h>
14 #include <linux/errno.h>
15 #include <linux/init.h>
16 #include <linux/mutex.h>
17 #include <linux/oprofile.h>
18 #include <linux/perf_event.h>
19 #include <linux/platform_device.h>
20 #include <linux/slab.h>
21 #include <asm/stacktrace.h>
22 #include <linux/uaccess.h>
23
24 #include <asm/perf_event.h>
25 #include <asm/ptrace.h>
26
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 };
40
41 static int oprofile_perf_enabled;
42 static DEFINE_MUTEX(oprofile_perf_mutex);
43
44 static struct op_counter_config *counter_config;
45 static struct perf_event **perf_events[nr_cpumask_bits];
46 static int 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 < num_counters; ++id)
58                 if (perf_events[cpu][id] == event)
59                         break;
60
61         if (id != 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 oprofile_perf_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 < 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) {
105                 pr_warning("oprofile: failed to enable event %d "
106                                 "on CPU %d\n", event, cpu);
107                 ret = -EBUSY;
108         } else {
109                 perf_events[cpu][event] = pevent;
110         }
111
112         return ret;
113 }
114
115 static void op_destroy_counter(int cpu, int event)
116 {
117         struct perf_event *pevent = perf_events[cpu][event];
118
119         if (pevent) {
120                 perf_event_release_kernel(pevent);
121                 perf_events[cpu][event] = NULL;
122         }
123 }
124
125 /*
126  * Called by oprofile_perf_start to create active perf events based on the
127  * perviously configured attributes.
128  */
129 static int op_perf_start(void)
130 {
131         int cpu, event, ret = 0;
132
133         for_each_online_cpu(cpu) {
134                 for (event = 0; event < num_counters; ++event) {
135                         ret = op_create_counter(cpu, event);
136                         if (ret)
137                                 goto out;
138                 }
139         }
140
141 out:
142         return ret;
143 }
144
145 /*
146  * Called by oprofile_perf_stop at the end of a profiling run.
147  */
148 static void op_perf_stop(void)
149 {
150         int cpu, event;
151
152         for_each_online_cpu(cpu)
153                 for (event = 0; event < num_counters; ++event)
154                         op_destroy_counter(cpu, event);
155 }
156
157
158 char *op_name_from_perf_id(void)
159 {
160         enum arm_perf_pmu_ids id = armpmu_get_pmu_id();
161
162         switch (id) {
163         case ARM_PERF_PMU_ID_XSCALE1:
164                 return "arm/xscale1";
165         case ARM_PERF_PMU_ID_XSCALE2:
166                 return "arm/xscale2";
167         case ARM_PERF_PMU_ID_V6:
168                 return "arm/armv6";
169         case ARM_PERF_PMU_ID_V6MP:
170                 return "arm/mpcore";
171         case ARM_PERF_PMU_ID_CA8:
172                 return "arm/armv7";
173         case ARM_PERF_PMU_ID_CA9:
174                 return "arm/armv7-ca9";
175         default:
176                 return NULL;
177         }
178 }
179
180 static int oprofile_perf_create_files(struct super_block *sb, struct dentry *root)
181 {
182         unsigned int i;
183
184         for (i = 0; i < num_counters; i++) {
185                 struct dentry *dir;
186                 char buf[4];
187
188                 snprintf(buf, sizeof buf, "%d", i);
189                 dir = oprofilefs_mkdir(sb, root, buf);
190                 oprofilefs_create_ulong(sb, dir, "enabled", &counter_config[i].enabled);
191                 oprofilefs_create_ulong(sb, dir, "event", &counter_config[i].event);
192                 oprofilefs_create_ulong(sb, dir, "count", &counter_config[i].count);
193                 oprofilefs_create_ulong(sb, dir, "unit_mask", &counter_config[i].unit_mask);
194                 oprofilefs_create_ulong(sb, dir, "kernel", &counter_config[i].kernel);
195                 oprofilefs_create_ulong(sb, dir, "user", &counter_config[i].user);
196         }
197
198         return 0;
199 }
200
201 static int oprofile_perf_setup(void)
202 {
203         spin_lock(&oprofilefs_lock);
204         op_perf_setup();
205         spin_unlock(&oprofilefs_lock);
206         return 0;
207 }
208
209 static int oprofile_perf_start(void)
210 {
211         int ret = -EBUSY;
212
213         mutex_lock(&oprofile_perf_mutex);
214         if (!oprofile_perf_enabled) {
215                 ret = 0;
216                 op_perf_start();
217                 oprofile_perf_enabled = 1;
218         }
219         mutex_unlock(&oprofile_perf_mutex);
220         return ret;
221 }
222
223 static void oprofile_perf_stop(void)
224 {
225         mutex_lock(&oprofile_perf_mutex);
226         if (oprofile_perf_enabled)
227                 op_perf_stop();
228         oprofile_perf_enabled = 0;
229         mutex_unlock(&oprofile_perf_mutex);
230 }
231
232 #ifdef CONFIG_PM
233 static int oprofile_perf_suspend(struct platform_device *dev, pm_message_t state)
234 {
235         mutex_lock(&oprofile_perf_mutex);
236         if (oprofile_perf_enabled)
237                 op_perf_stop();
238         mutex_unlock(&oprofile_perf_mutex);
239         return 0;
240 }
241
242 static int oprofile_perf_resume(struct platform_device *dev)
243 {
244         mutex_lock(&oprofile_perf_mutex);
245         if (oprofile_perf_enabled && op_perf_start())
246                 oprofile_perf_enabled = 0;
247         mutex_unlock(&oprofile_perf_mutex);
248         return 0;
249 }
250
251 static struct platform_driver oprofile_driver = {
252         .driver         = {
253                 .name           = "oprofile-perf",
254         },
255         .resume         = oprofile_perf_resume,
256         .suspend        = oprofile_perf_suspend,
257 };
258
259 static struct platform_device *oprofile_pdev;
260
261 static int __init init_driverfs(void)
262 {
263         int ret;
264
265         ret = platform_driver_register(&oprofile_driver);
266         if (ret)
267                 goto out;
268
269         oprofile_pdev = platform_device_register_simple(
270                                 oprofile_driver.driver.name, 0, NULL, 0);
271         if (IS_ERR(oprofile_pdev)) {
272                 ret = PTR_ERR(oprofile_pdev);
273                 platform_driver_unregister(&oprofile_driver);
274         }
275
276 out:
277         return ret;
278 }
279
280 static void __exit exit_driverfs(void)
281 {
282         platform_device_unregister(oprofile_pdev);
283         platform_driver_unregister(&oprofile_driver);
284 }
285 #else
286 static int __init init_driverfs(void) { return 0; }
287 #define exit_driverfs() do { } while (0)
288 #endif /* CONFIG_PM */
289
290 static int report_trace(struct stackframe *frame, void *d)
291 {
292         unsigned int *depth = d;
293
294         if (*depth) {
295                 oprofile_add_trace(frame->pc);
296                 (*depth)--;
297         }
298
299         return *depth == 0;
300 }
301
302 /*
303  * The registers we're interested in are at the end of the variable
304  * length saved register structure. The fp points at the end of this
305  * structure so the address of this struct is:
306  * (struct frame_tail *)(xxx->fp)-1
307  */
308 struct frame_tail {
309         struct frame_tail *fp;
310         unsigned long sp;
311         unsigned long lr;
312 } __attribute__((packed));
313
314 static struct frame_tail* user_backtrace(struct frame_tail *tail)
315 {
316         struct frame_tail buftail[2];
317
318         /* Also check accessibility of one struct frame_tail beyond */
319         if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
320                 return NULL;
321         if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail)))
322                 return NULL;
323
324         oprofile_add_trace(buftail[0].lr);
325
326         /* frame pointers should strictly progress back up the stack
327          * (towards higher addresses) */
328         if (tail >= buftail[0].fp)
329                 return NULL;
330
331         return buftail[0].fp-1;
332 }
333
334 static void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
335 {
336         struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;
337
338         if (!user_mode(regs)) {
339                 struct stackframe frame;
340                 frame.fp = regs->ARM_fp;
341                 frame.sp = regs->ARM_sp;
342                 frame.lr = regs->ARM_lr;
343                 frame.pc = regs->ARM_pc;
344                 walk_stackframe(&frame, report_trace, &depth);
345                 return;
346         }
347
348         while (depth-- && tail && !((unsigned long) tail & 3))
349                 tail = user_backtrace(tail);
350 }
351
352 int __init oprofile_perf_init(struct oprofile_operations *ops)
353 {
354         int cpu, ret = 0;
355
356         memset(&perf_events, 0, sizeof(perf_events));
357
358         num_counters = perf_num_counters();
359         if (num_counters <= 0) {
360                 pr_info("oprofile: no performance counters\n");
361                 ret = -ENODEV;
362                 goto out;
363         }
364
365         counter_config = kcalloc(num_counters,
366                         sizeof(struct op_counter_config), GFP_KERNEL);
367
368         if (!counter_config) {
369                 pr_info("oprofile: failed to allocate %d "
370                                 "counters\n", num_counters);
371                 ret = -ENOMEM;
372                 goto out;
373         }
374
375         ret = init_driverfs();
376         if (ret)
377                 goto out;
378
379         for_each_possible_cpu(cpu) {
380                 perf_events[cpu] = kcalloc(num_counters,
381                                 sizeof(struct perf_event *), GFP_KERNEL);
382                 if (!perf_events[cpu]) {
383                         pr_info("oprofile: failed to allocate %d perf events "
384                                         "for cpu %d\n", num_counters, cpu);
385                         ret = -ENOMEM;
386                         goto out;
387                 }
388         }
389
390         ops->create_files       = oprofile_perf_create_files;
391         ops->setup              = oprofile_perf_setup;
392         ops->start              = oprofile_perf_start;
393         ops->stop               = oprofile_perf_stop;
394         ops->shutdown           = oprofile_perf_stop;
395         ops->cpu_type           = op_name_from_perf_id();
396
397         if (!ops->cpu_type)
398                 ret = -ENODEV;
399         else
400                 pr_info("oprofile: using %s\n", ops->cpu_type);
401
402 out:
403         if (ret) {
404                 for_each_possible_cpu(cpu)
405                         kfree(perf_events[cpu]);
406                 kfree(counter_config);
407         }
408
409         return ret;
410 }
411
412 int __init oprofile_arch_init(struct oprofile_operations *ops)
413 {
414         ops->backtrace          = arm_backtrace;
415
416         return oprofile_perf_init(ops);
417 }
418
419 void __exit oprofile_perf_exit(void)
420 {
421         int cpu, id;
422         struct perf_event *event;
423
424         for_each_possible_cpu(cpu) {
425                 for (id = 0; id < num_counters; ++id) {
426                         event = perf_events[cpu][id];
427                         if (event)
428                                 perf_event_release_kernel(event);
429                 }
430
431                 kfree(perf_events[cpu]);
432         }
433
434         kfree(counter_config);
435         exit_driverfs();
436 }
437
438 void __exit oprofile_arch_exit(void)
439 {
440         oprofile_perf_exit();
441 }
442 #else
443 int __init oprofile_arch_init(struct oprofile_operations *ops)
444 {
445         pr_info("oprofile: hardware counters not available\n");
446         return -ENODEV;
447 }
448 void __exit oprofile_arch_exit(void) {}
449 #endif /* CONFIG_HW_PERF_EVENTS */