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1/*
2 * linux/kernel/profile.c
3 * Simple profiling. Manages a direct-mapped profile hit count buffer,
4 * with configurable resolution, support for restricting the cpus on
5 * which profiling is done, and switching between cpu time and
6 * schedule() calls via kernel command line parameters passed at boot.
7 *
8 * Scheduler profiling support, Arjan van de Ven and Ingo Molnar,
9 * Red Hat, July 2004
10 * Consolidation of architecture support code for profiling,
11 * Nadia Yvette Chambers, Oracle, July 2004
12 * Amortized hit count accounting via per-cpu open-addressed hashtables
13 * to resolve timer interrupt livelocks, Nadia Yvette Chambers,
14 * Oracle, 2004
15 */
16
17#include <linux/export.h>
18#include <linux/profile.h>
19#include <linux/bootmem.h>
20#include <linux/notifier.h>
21#include <linux/mm.h>
22#include <linux/cpumask.h>
23#include <linux/cpu.h>
24#include <linux/highmem.h>
25#include <linux/mutex.h>
26#include <linux/slab.h>
27#include <linux/vmalloc.h>
28#include <asm/sections.h>
29#include <asm/irq_regs.h>
30#include <asm/ptrace.h>
31
32struct profile_hit {
33 u32 pc, hits;
34};
35#define PROFILE_GRPSHIFT 3
36#define PROFILE_GRPSZ (1 << PROFILE_GRPSHIFT)
37#define NR_PROFILE_HIT (PAGE_SIZE/sizeof(struct profile_hit))
38#define NR_PROFILE_GRP (NR_PROFILE_HIT/PROFILE_GRPSZ)
39
40static atomic_t *prof_buffer;
41static unsigned long prof_len, prof_shift;
42
43int prof_on __read_mostly;
44EXPORT_SYMBOL_GPL(prof_on);
45
46static cpumask_var_t prof_cpu_mask;
47#if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
48static DEFINE_PER_CPU(struct profile_hit *[2], cpu_profile_hits);
49static DEFINE_PER_CPU(int, cpu_profile_flip);
50static DEFINE_MUTEX(profile_flip_mutex);
51#endif /* CONFIG_SMP */
52
53int profile_setup(char *str)
54{
55 static const char schedstr[] = "schedule";
56 static const char sleepstr[] = "sleep";
57 static const char kvmstr[] = "kvm";
58 int par;
59
60 if (!strncmp(str, sleepstr, strlen(sleepstr))) {
61#ifdef CONFIG_SCHEDSTATS
62 force_schedstat_enabled();
63 prof_on = SLEEP_PROFILING;
64 if (str[strlen(sleepstr)] == ',')
65 str += strlen(sleepstr) + 1;
66 if (get_option(&str, &par))
67 prof_shift = par;
68 pr_info("kernel sleep profiling enabled (shift: %ld)\n",
69 prof_shift);
70#else
71 pr_warn("kernel sleep profiling requires CONFIG_SCHEDSTATS\n");
72#endif /* CONFIG_SCHEDSTATS */
73 } else if (!strncmp(str, schedstr, strlen(schedstr))) {
74 prof_on = SCHED_PROFILING;
75 if (str[strlen(schedstr)] == ',')
76 str += strlen(schedstr) + 1;
77 if (get_option(&str, &par))
78 prof_shift = par;
79 pr_info("kernel schedule profiling enabled (shift: %ld)\n",
80 prof_shift);
81 } else if (!strncmp(str, kvmstr, strlen(kvmstr))) {
82 prof_on = KVM_PROFILING;
83 if (str[strlen(kvmstr)] == ',')
84 str += strlen(kvmstr) + 1;
85 if (get_option(&str, &par))
86 prof_shift = par;
87 pr_info("kernel KVM profiling enabled (shift: %ld)\n",
88 prof_shift);
89 } else if (get_option(&str, &par)) {
90 prof_shift = par;
91 prof_on = CPU_PROFILING;
92 pr_info("kernel profiling enabled (shift: %ld)\n",
93 prof_shift);
94 }
95 return 1;
96}
97__setup("profile=", profile_setup);
98
99
100int __ref profile_init(void)
101{
102 int buffer_bytes;
103 if (!prof_on)
104 return 0;
105
106 /* only text is profiled */
107 prof_len = (_etext - _stext) >> prof_shift;
108 buffer_bytes = prof_len*sizeof(atomic_t);
109
110 if (!alloc_cpumask_var(&prof_cpu_mask, GFP_KERNEL))
111 return -ENOMEM;
112
113 cpumask_copy(prof_cpu_mask, cpu_possible_mask);
114
115 prof_buffer = kzalloc(buffer_bytes, GFP_KERNEL|__GFP_NOWARN);
116 if (prof_buffer)
117 return 0;
118
119 prof_buffer = alloc_pages_exact(buffer_bytes,
120 GFP_KERNEL|__GFP_ZERO|__GFP_NOWARN);
121 if (prof_buffer)
122 return 0;
123
124 prof_buffer = vzalloc(buffer_bytes);
125 if (prof_buffer)
126 return 0;
127
128 free_cpumask_var(prof_cpu_mask);
129 return -ENOMEM;
130}
131
132/* Profile event notifications */
133
134static BLOCKING_NOTIFIER_HEAD(task_exit_notifier);
135static ATOMIC_NOTIFIER_HEAD(task_free_notifier);
136static BLOCKING_NOTIFIER_HEAD(munmap_notifier);
137
138void profile_task_exit(struct task_struct *task)
139{
140 blocking_notifier_call_chain(&task_exit_notifier, 0, task);
141}
142
143int profile_handoff_task(struct task_struct *task)
144{
145 int ret;
146 ret = atomic_notifier_call_chain(&task_free_notifier, 0, task);
147 return (ret == NOTIFY_OK) ? 1 : 0;
148}
149
150void profile_munmap(unsigned long addr)
151{
152 blocking_notifier_call_chain(&munmap_notifier, 0, (void *)addr);
153}
154
155int task_handoff_register(struct notifier_block *n)
156{
157 return atomic_notifier_chain_register(&task_free_notifier, n);
158}
159EXPORT_SYMBOL_GPL(task_handoff_register);
160
161int task_handoff_unregister(struct notifier_block *n)
162{
163 return atomic_notifier_chain_unregister(&task_free_notifier, n);
164}
165EXPORT_SYMBOL_GPL(task_handoff_unregister);
166
167int profile_event_register(enum profile_type type, struct notifier_block *n)
168{
169 int err = -EINVAL;
170
171 switch (type) {
172 case PROFILE_TASK_EXIT:
173 err = blocking_notifier_chain_register(
174 &task_exit_notifier, n);
175 break;
176 case PROFILE_MUNMAP:
177 err = blocking_notifier_chain_register(
178 &munmap_notifier, n);
179 break;
180 }
181
182 return err;
183}
184EXPORT_SYMBOL_GPL(profile_event_register);
185
186int profile_event_unregister(enum profile_type type, struct notifier_block *n)
187{
188 int err = -EINVAL;
189
190 switch (type) {
191 case PROFILE_TASK_EXIT:
192 err = blocking_notifier_chain_unregister(
193 &task_exit_notifier, n);
194 break;
195 case PROFILE_MUNMAP:
196 err = blocking_notifier_chain_unregister(
197 &munmap_notifier, n);
198 break;
199 }
200
201 return err;
202}
203EXPORT_SYMBOL_GPL(profile_event_unregister);
204
205#if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
206/*
207 * Each cpu has a pair of open-addressed hashtables for pending
208 * profile hits. read_profile() IPI's all cpus to request them
209 * to flip buffers and flushes their contents to prof_buffer itself.
210 * Flip requests are serialized by the profile_flip_mutex. The sole
211 * use of having a second hashtable is for avoiding cacheline
212 * contention that would otherwise happen during flushes of pending
213 * profile hits required for the accuracy of reported profile hits
214 * and so resurrect the interrupt livelock issue.
215 *
216 * The open-addressed hashtables are indexed by profile buffer slot
217 * and hold the number of pending hits to that profile buffer slot on
218 * a cpu in an entry. When the hashtable overflows, all pending hits
219 * are accounted to their corresponding profile buffer slots with
220 * atomic_add() and the hashtable emptied. As numerous pending hits
221 * may be accounted to a profile buffer slot in a hashtable entry,
222 * this amortizes a number of atomic profile buffer increments likely
223 * to be far larger than the number of entries in the hashtable,
224 * particularly given that the number of distinct profile buffer
225 * positions to which hits are accounted during short intervals (e.g.
226 * several seconds) is usually very small. Exclusion from buffer
227 * flipping is provided by interrupt disablement (note that for
228 * SCHED_PROFILING or SLEEP_PROFILING profile_hit() may be called from
229 * process context).
230 * The hash function is meant to be lightweight as opposed to strong,
231 * and was vaguely inspired by ppc64 firmware-supported inverted
232 * pagetable hash functions, but uses a full hashtable full of finite
233 * collision chains, not just pairs of them.
234 *
235 * -- nyc
236 */
237static void __profile_flip_buffers(void *unused)
238{
239 int cpu = smp_processor_id();
240
241 per_cpu(cpu_profile_flip, cpu) = !per_cpu(cpu_profile_flip, cpu);
242}
243
244static void profile_flip_buffers(void)
245{
246 int i, j, cpu;
247
248 mutex_lock(&profile_flip_mutex);
249 j = per_cpu(cpu_profile_flip, get_cpu());
250 put_cpu();
251 on_each_cpu(__profile_flip_buffers, NULL, 1);
252 for_each_online_cpu(cpu) {
253 struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[j];
254 for (i = 0; i < NR_PROFILE_HIT; ++i) {
255 if (!hits[i].hits) {
256 if (hits[i].pc)
257 hits[i].pc = 0;
258 continue;
259 }
260 atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
261 hits[i].hits = hits[i].pc = 0;
262 }
263 }
264 mutex_unlock(&profile_flip_mutex);
265}
266
267static void profile_discard_flip_buffers(void)
268{
269 int i, cpu;
270
271 mutex_lock(&profile_flip_mutex);
272 i = per_cpu(cpu_profile_flip, get_cpu());
273 put_cpu();
274 on_each_cpu(__profile_flip_buffers, NULL, 1);
275 for_each_online_cpu(cpu) {
276 struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[i];
277 memset(hits, 0, NR_PROFILE_HIT*sizeof(struct profile_hit));
278 }
279 mutex_unlock(&profile_flip_mutex);
280}
281
282static void do_profile_hits(int type, void *__pc, unsigned int nr_hits)
283{
284 unsigned long primary, secondary, flags, pc = (unsigned long)__pc;
285 int i, j, cpu;
286 struct profile_hit *hits;
287
288 pc = min((pc - (unsigned long)_stext) >> prof_shift, prof_len - 1);
289 i = primary = (pc & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
290 secondary = (~(pc << 1) & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
291 cpu = get_cpu();
292 hits = per_cpu(cpu_profile_hits, cpu)[per_cpu(cpu_profile_flip, cpu)];
293 if (!hits) {
294 put_cpu();
295 return;
296 }
297 /*
298 * We buffer the global profiler buffer into a per-CPU
299 * queue and thus reduce the number of global (and possibly
300 * NUMA-alien) accesses. The write-queue is self-coalescing:
301 */
302 local_irq_save(flags);
303 do {
304 for (j = 0; j < PROFILE_GRPSZ; ++j) {
305 if (hits[i + j].pc == pc) {
306 hits[i + j].hits += nr_hits;
307 goto out;
308 } else if (!hits[i + j].hits) {
309 hits[i + j].pc = pc;
310 hits[i + j].hits = nr_hits;
311 goto out;
312 }
313 }
314 i = (i + secondary) & (NR_PROFILE_HIT - 1);
315 } while (i != primary);
316
317 /*
318 * Add the current hit(s) and flush the write-queue out
319 * to the global buffer:
320 */
321 atomic_add(nr_hits, &prof_buffer[pc]);
322 for (i = 0; i < NR_PROFILE_HIT; ++i) {
323 atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
324 hits[i].pc = hits[i].hits = 0;
325 }
326out:
327 local_irq_restore(flags);
328 put_cpu();
329}
330
331static int profile_dead_cpu(unsigned int cpu)
332{
333 struct page *page;
334 int i;
335
336 if (prof_cpu_mask != NULL)
337 cpumask_clear_cpu(cpu, prof_cpu_mask);
338
339 for (i = 0; i < 2; i++) {
340 if (per_cpu(cpu_profile_hits, cpu)[i]) {
341 page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[i]);
342 per_cpu(cpu_profile_hits, cpu)[i] = NULL;
343 __free_page(page);
344 }
345 }
346 return 0;
347}
348
349static int profile_prepare_cpu(unsigned int cpu)
350{
351 int i, node = cpu_to_mem(cpu);
352 struct page *page;
353
354 per_cpu(cpu_profile_flip, cpu) = 0;
355
356 for (i = 0; i < 2; i++) {
357 if (per_cpu(cpu_profile_hits, cpu)[i])
358 continue;
359
360 page = __alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
361 if (!page) {
362 profile_dead_cpu(cpu);
363 return -ENOMEM;
364 }
365 per_cpu(cpu_profile_hits, cpu)[i] = page_address(page);
366
367 }
368 return 0;
369}
370
371static int profile_online_cpu(unsigned int cpu)
372{
373 if (prof_cpu_mask != NULL)
374 cpumask_set_cpu(cpu, prof_cpu_mask);
375
376 return 0;
377}
378
379#else /* !CONFIG_SMP */
380#define profile_flip_buffers() do { } while (0)
381#define profile_discard_flip_buffers() do { } while (0)
382
383static void do_profile_hits(int type, void *__pc, unsigned int nr_hits)
384{
385 unsigned long pc;
386 pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift;
387 atomic_add(nr_hits, &prof_buffer[min(pc, prof_len - 1)]);
388}
389#endif /* !CONFIG_SMP */
390
391void profile_hits(int type, void *__pc, unsigned int nr_hits)
392{
393 if (prof_on != type || !prof_buffer)
394 return;
395 do_profile_hits(type, __pc, nr_hits);
396}
397EXPORT_SYMBOL_GPL(profile_hits);
398
399void profile_tick(int type)
400{
401 struct pt_regs *regs = get_irq_regs();
402
403 if (!user_mode(regs) && prof_cpu_mask != NULL &&
404 cpumask_test_cpu(smp_processor_id(), prof_cpu_mask))
405 profile_hit(type, (void *)profile_pc(regs));
406}
407
408#ifdef CONFIG_PROC_FS
409#include <linux/proc_fs.h>
410#include <linux/seq_file.h>
411#include <linux/uaccess.h>
412
413static int prof_cpu_mask_proc_show(struct seq_file *m, void *v)
414{
415 seq_printf(m, "%*pb\n", cpumask_pr_args(prof_cpu_mask));
416 return 0;
417}
418
419static int prof_cpu_mask_proc_open(struct inode *inode, struct file *file)
420{
421 return single_open(file, prof_cpu_mask_proc_show, NULL);
422}
423
424static ssize_t prof_cpu_mask_proc_write(struct file *file,
425 const char __user *buffer, size_t count, loff_t *pos)
426{
427 cpumask_var_t new_value;
428 int err;
429
430 if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
431 return -ENOMEM;
432
433 err = cpumask_parse_user(buffer, count, new_value);
434 if (!err) {
435 cpumask_copy(prof_cpu_mask, new_value);
436 err = count;
437 }
438 free_cpumask_var(new_value);
439 return err;
440}
441
442static const struct file_operations prof_cpu_mask_proc_fops = {
443 .open = prof_cpu_mask_proc_open,
444 .read = seq_read,
445 .llseek = seq_lseek,
446 .release = single_release,
447 .write = prof_cpu_mask_proc_write,
448};
449
450void create_prof_cpu_mask(void)
451{
452 /* create /proc/irq/prof_cpu_mask */
453 proc_create("irq/prof_cpu_mask", 0600, NULL, &prof_cpu_mask_proc_fops);
454}
455
456/*
457 * This function accesses profiling information. The returned data is
458 * binary: the sampling step and the actual contents of the profile
459 * buffer. Use of the program readprofile is recommended in order to
460 * get meaningful info out of these data.
461 */
462static ssize_t
463read_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos)
464{
465 unsigned long p = *ppos;
466 ssize_t read;
467 char *pnt;
468 unsigned int sample_step = 1 << prof_shift;
469
470 profile_flip_buffers();
471 if (p >= (prof_len+1)*sizeof(unsigned int))
472 return 0;
473 if (count > (prof_len+1)*sizeof(unsigned int) - p)
474 count = (prof_len+1)*sizeof(unsigned int) - p;
475 read = 0;
476
477 while (p < sizeof(unsigned int) && count > 0) {
478 if (put_user(*((char *)(&sample_step)+p), buf))
479 return -EFAULT;
480 buf++; p++; count--; read++;
481 }
482 pnt = (char *)prof_buffer + p - sizeof(atomic_t);
483 if (copy_to_user(buf, (void *)pnt, count))
484 return -EFAULT;
485 read += count;
486 *ppos += read;
487 return read;
488}
489
490/*
491 * Writing to /proc/profile resets the counters
492 *
493 * Writing a 'profiling multiplier' value into it also re-sets the profiling
494 * interrupt frequency, on architectures that support this.
495 */
496static ssize_t write_profile(struct file *file, const char __user *buf,
497 size_t count, loff_t *ppos)
498{
499#ifdef CONFIG_SMP
500 extern int setup_profiling_timer(unsigned int multiplier);
501
502 if (count == sizeof(int)) {
503 unsigned int multiplier;
504
505 if (copy_from_user(&multiplier, buf, sizeof(int)))
506 return -EFAULT;
507
508 if (setup_profiling_timer(multiplier))
509 return -EINVAL;
510 }
511#endif
512 profile_discard_flip_buffers();
513 memset(prof_buffer, 0, prof_len * sizeof(atomic_t));
514 return count;
515}
516
517static const struct file_operations proc_profile_operations = {
518 .read = read_profile,
519 .write = write_profile,
520 .llseek = default_llseek,
521};
522
523int __ref create_proc_profile(void)
524{
525 struct proc_dir_entry *entry;
526#ifdef CONFIG_SMP
527 enum cpuhp_state online_state;
528#endif
529
530 int err = 0;
531
532 if (!prof_on)
533 return 0;
534#ifdef CONFIG_SMP
535 err = cpuhp_setup_state(CPUHP_PROFILE_PREPARE, "PROFILE_PREPARE",
536 profile_prepare_cpu, profile_dead_cpu);
537 if (err)
538 return err;
539
540 err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "AP_PROFILE_ONLINE",
541 profile_online_cpu, NULL);
542 if (err < 0)
543 goto err_state_prep;
544 online_state = err;
545 err = 0;
546#endif
547 entry = proc_create("profile", S_IWUSR | S_IRUGO,
548 NULL, &proc_profile_operations);
549 if (!entry)
550 goto err_state_onl;
551 proc_set_size(entry, (1 + prof_len) * sizeof(atomic_t));
552
553 return err;
554err_state_onl:
555#ifdef CONFIG_SMP
556 cpuhp_remove_state(online_state);
557err_state_prep:
558 cpuhp_remove_state(CPUHP_PROFILE_PREPARE);
559#endif
560 return err;
561}
562subsys_initcall(create_proc_profile);
563#endif /* CONFIG_PROC_FS */
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/kernel/profile.c
4 * Simple profiling. Manages a direct-mapped profile hit count buffer,
5 * with configurable resolution, support for restricting the cpus on
6 * which profiling is done, and switching between cpu time and
7 * schedule() calls via kernel command line parameters passed at boot.
8 *
9 * Scheduler profiling support, Arjan van de Ven and Ingo Molnar,
10 * Red Hat, July 2004
11 * Consolidation of architecture support code for profiling,
12 * Nadia Yvette Chambers, Oracle, July 2004
13 * Amortized hit count accounting via per-cpu open-addressed hashtables
14 * to resolve timer interrupt livelocks, Nadia Yvette Chambers,
15 * Oracle, 2004
16 */
17
18#include <linux/export.h>
19#include <linux/profile.h>
20#include <linux/memblock.h>
21#include <linux/notifier.h>
22#include <linux/mm.h>
23#include <linux/cpumask.h>
24#include <linux/cpu.h>
25#include <linux/highmem.h>
26#include <linux/mutex.h>
27#include <linux/slab.h>
28#include <linux/vmalloc.h>
29#include <linux/sched/stat.h>
30
31#include <asm/sections.h>
32#include <asm/irq_regs.h>
33#include <asm/ptrace.h>
34
35struct profile_hit {
36 u32 pc, hits;
37};
38#define PROFILE_GRPSHIFT 3
39#define PROFILE_GRPSZ (1 << PROFILE_GRPSHIFT)
40#define NR_PROFILE_HIT (PAGE_SIZE/sizeof(struct profile_hit))
41#define NR_PROFILE_GRP (NR_PROFILE_HIT/PROFILE_GRPSZ)
42
43static atomic_t *prof_buffer;
44static unsigned long prof_len;
45static unsigned short int prof_shift;
46
47int prof_on __read_mostly;
48EXPORT_SYMBOL_GPL(prof_on);
49
50int profile_setup(char *str)
51{
52 static const char schedstr[] = "schedule";
53 static const char kvmstr[] = "kvm";
54 const char *select = NULL;
55 int par;
56
57 if (!strncmp(str, schedstr, strlen(schedstr))) {
58 prof_on = SCHED_PROFILING;
59 select = schedstr;
60 } else if (!strncmp(str, kvmstr, strlen(kvmstr))) {
61 prof_on = KVM_PROFILING;
62 select = kvmstr;
63 } else if (get_option(&str, &par)) {
64 prof_shift = clamp(par, 0, BITS_PER_LONG - 1);
65 prof_on = CPU_PROFILING;
66 pr_info("kernel profiling enabled (shift: %u)\n",
67 prof_shift);
68 }
69
70 if (select) {
71 if (str[strlen(select)] == ',')
72 str += strlen(select) + 1;
73 if (get_option(&str, &par))
74 prof_shift = clamp(par, 0, BITS_PER_LONG - 1);
75 pr_info("kernel %s profiling enabled (shift: %u)\n",
76 select, prof_shift);
77 }
78
79 return 1;
80}
81__setup("profile=", profile_setup);
82
83
84int __ref profile_init(void)
85{
86 int buffer_bytes;
87 if (!prof_on)
88 return 0;
89
90 /* only text is profiled */
91 prof_len = (_etext - _stext) >> prof_shift;
92
93 if (!prof_len) {
94 pr_warn("profiling shift: %u too large\n", prof_shift);
95 prof_on = 0;
96 return -EINVAL;
97 }
98
99 buffer_bytes = prof_len*sizeof(atomic_t);
100
101 prof_buffer = kzalloc(buffer_bytes, GFP_KERNEL|__GFP_NOWARN);
102 if (prof_buffer)
103 return 0;
104
105 prof_buffer = alloc_pages_exact(buffer_bytes,
106 GFP_KERNEL|__GFP_ZERO|__GFP_NOWARN);
107 if (prof_buffer)
108 return 0;
109
110 prof_buffer = vzalloc(buffer_bytes);
111 if (prof_buffer)
112 return 0;
113
114 return -ENOMEM;
115}
116
117static void do_profile_hits(int type, void *__pc, unsigned int nr_hits)
118{
119 unsigned long pc;
120 pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift;
121 if (pc < prof_len)
122 atomic_add(nr_hits, &prof_buffer[pc]);
123}
124
125void profile_hits(int type, void *__pc, unsigned int nr_hits)
126{
127 if (prof_on != type || !prof_buffer)
128 return;
129 do_profile_hits(type, __pc, nr_hits);
130}
131EXPORT_SYMBOL_GPL(profile_hits);
132
133void profile_tick(int type)
134{
135 struct pt_regs *regs = get_irq_regs();
136
137 /* This is the old kernel-only legacy profiling */
138 if (!user_mode(regs))
139 profile_hit(type, (void *)profile_pc(regs));
140}
141
142#ifdef CONFIG_PROC_FS
143#include <linux/proc_fs.h>
144#include <linux/seq_file.h>
145#include <linux/uaccess.h>
146
147/*
148 * This function accesses profiling information. The returned data is
149 * binary: the sampling step and the actual contents of the profile
150 * buffer. Use of the program readprofile is recommended in order to
151 * get meaningful info out of these data.
152 */
153static ssize_t
154read_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos)
155{
156 unsigned long p = *ppos;
157 ssize_t read;
158 char *pnt;
159 unsigned long sample_step = 1UL << prof_shift;
160
161 if (p >= (prof_len+1)*sizeof(unsigned int))
162 return 0;
163 if (count > (prof_len+1)*sizeof(unsigned int) - p)
164 count = (prof_len+1)*sizeof(unsigned int) - p;
165 read = 0;
166
167 while (p < sizeof(unsigned int) && count > 0) {
168 if (put_user(*((char *)(&sample_step)+p), buf))
169 return -EFAULT;
170 buf++; p++; count--; read++;
171 }
172 pnt = (char *)prof_buffer + p - sizeof(atomic_t);
173 if (copy_to_user(buf, (void *)pnt, count))
174 return -EFAULT;
175 read += count;
176 *ppos += read;
177 return read;
178}
179
180/* default is to not implement this call */
181int __weak setup_profiling_timer(unsigned mult)
182{
183 return -EINVAL;
184}
185
186/*
187 * Writing to /proc/profile resets the counters
188 *
189 * Writing a 'profiling multiplier' value into it also re-sets the profiling
190 * interrupt frequency, on architectures that support this.
191 */
192static ssize_t write_profile(struct file *file, const char __user *buf,
193 size_t count, loff_t *ppos)
194{
195#ifdef CONFIG_SMP
196 if (count == sizeof(int)) {
197 unsigned int multiplier;
198
199 if (copy_from_user(&multiplier, buf, sizeof(int)))
200 return -EFAULT;
201
202 if (setup_profiling_timer(multiplier))
203 return -EINVAL;
204 }
205#endif
206 memset(prof_buffer, 0, prof_len * sizeof(atomic_t));
207 return count;
208}
209
210static const struct proc_ops profile_proc_ops = {
211 .proc_read = read_profile,
212 .proc_write = write_profile,
213 .proc_lseek = default_llseek,
214};
215
216int __ref create_proc_profile(void)
217{
218 struct proc_dir_entry *entry;
219 int err = 0;
220
221 if (!prof_on)
222 return 0;
223 entry = proc_create("profile", S_IWUSR | S_IRUGO,
224 NULL, &profile_proc_ops);
225 if (entry)
226 proc_set_size(entry, (1 + prof_len) * sizeof(atomic_t));
227 return err;
228}
229subsys_initcall(create_proc_profile);
230#endif /* CONFIG_PROC_FS */