microblaze: uaccess: fix put_user and get_user macros
[linux-2.6.git] / kernel / profile.c
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  *      William Irwin, Oracle, July 2004
12  *  Amortized hit count accounting via per-cpu open-addressed hashtables
13  *      to resolve timer interrupt livelocks, William Irwin, Oracle, 2004
14  */
15
16 #include <linux/module.h>
17 #include <linux/profile.h>
18 #include <linux/bootmem.h>
19 #include <linux/notifier.h>
20 #include <linux/mm.h>
21 #include <linux/cpumask.h>
22 #include <linux/cpu.h>
23 #include <linux/highmem.h>
24 #include <linux/mutex.h>
25 #include <linux/slab.h>
26 #include <linux/vmalloc.h>
27 #include <asm/sections.h>
28 #include <asm/irq_regs.h>
29 #include <asm/ptrace.h>
30
31 struct profile_hit {
32         u32 pc, hits;
33 };
34 #define PROFILE_GRPSHIFT        3
35 #define PROFILE_GRPSZ           (1 << PROFILE_GRPSHIFT)
36 #define NR_PROFILE_HIT          (PAGE_SIZE/sizeof(struct profile_hit))
37 #define NR_PROFILE_GRP          (NR_PROFILE_HIT/PROFILE_GRPSZ)
38
39 /* Oprofile timer tick hook */
40 static int (*timer_hook)(struct pt_regs *) __read_mostly;
41
42 static atomic_t *prof_buffer;
43 static unsigned long prof_len, prof_shift;
44
45 int prof_on __read_mostly;
46 EXPORT_SYMBOL_GPL(prof_on);
47
48 static cpumask_var_t prof_cpu_mask;
49 #ifdef CONFIG_SMP
50 static DEFINE_PER_CPU(struct profile_hit *[2], cpu_profile_hits);
51 static DEFINE_PER_CPU(int, cpu_profile_flip);
52 static DEFINE_MUTEX(profile_flip_mutex);
53 #endif /* CONFIG_SMP */
54
55 int profile_setup(char *str)
56 {
57         static char schedstr[] = "schedule";
58         static char sleepstr[] = "sleep";
59         static char kvmstr[] = "kvm";
60         int par;
61
62         if (!strncmp(str, sleepstr, strlen(sleepstr))) {
63 #ifdef CONFIG_SCHEDSTATS
64                 prof_on = SLEEP_PROFILING;
65                 if (str[strlen(sleepstr)] == ',')
66                         str += strlen(sleepstr) + 1;
67                 if (get_option(&str, &par))
68                         prof_shift = par;
69                 printk(KERN_INFO
70                         "kernel sleep profiling enabled (shift: %ld)\n",
71                         prof_shift);
72 #else
73                 printk(KERN_WARNING
74                         "kernel sleep profiling requires CONFIG_SCHEDSTATS\n");
75 #endif /* CONFIG_SCHEDSTATS */
76         } else if (!strncmp(str, schedstr, strlen(schedstr))) {
77                 prof_on = SCHED_PROFILING;
78                 if (str[strlen(schedstr)] == ',')
79                         str += strlen(schedstr) + 1;
80                 if (get_option(&str, &par))
81                         prof_shift = par;
82                 printk(KERN_INFO
83                         "kernel schedule profiling enabled (shift: %ld)\n",
84                         prof_shift);
85         } else if (!strncmp(str, kvmstr, strlen(kvmstr))) {
86                 prof_on = KVM_PROFILING;
87                 if (str[strlen(kvmstr)] == ',')
88                         str += strlen(kvmstr) + 1;
89                 if (get_option(&str, &par))
90                         prof_shift = par;
91                 printk(KERN_INFO
92                         "kernel KVM profiling enabled (shift: %ld)\n",
93                         prof_shift);
94         } else if (get_option(&str, &par)) {
95                 prof_shift = par;
96                 prof_on = CPU_PROFILING;
97                 printk(KERN_INFO "kernel profiling enabled (shift: %ld)\n",
98                         prof_shift);
99         }
100         return 1;
101 }
102 __setup("profile=", profile_setup);
103
104
105 int __ref profile_init(void)
106 {
107         int buffer_bytes;
108         if (!prof_on)
109                 return 0;
110
111         /* only text is profiled */
112         prof_len = (_etext - _stext) >> prof_shift;
113         buffer_bytes = prof_len*sizeof(atomic_t);
114
115         if (!alloc_cpumask_var(&prof_cpu_mask, GFP_KERNEL))
116                 return -ENOMEM;
117
118         cpumask_copy(prof_cpu_mask, cpu_possible_mask);
119
120         prof_buffer = kzalloc(buffer_bytes, GFP_KERNEL|__GFP_NOWARN);
121         if (prof_buffer)
122                 return 0;
123
124         prof_buffer = alloc_pages_exact(buffer_bytes,
125                                         GFP_KERNEL|__GFP_ZERO|__GFP_NOWARN);
126         if (prof_buffer)
127                 return 0;
128
129         prof_buffer = vmalloc(buffer_bytes);
130         if (prof_buffer)
131                 return 0;
132
133         free_cpumask_var(prof_cpu_mask);
134         return -ENOMEM;
135 }
136
137 /* Profile event notifications */
138
139 static BLOCKING_NOTIFIER_HEAD(task_exit_notifier);
140 static ATOMIC_NOTIFIER_HEAD(task_free_notifier);
141 static BLOCKING_NOTIFIER_HEAD(munmap_notifier);
142
143 void profile_task_exit(struct task_struct *task)
144 {
145         blocking_notifier_call_chain(&task_exit_notifier, 0, task);
146 }
147
148 int profile_handoff_task(struct task_struct *task)
149 {
150         int ret;
151         ret = atomic_notifier_call_chain(&task_free_notifier, 0, task);
152         return (ret == NOTIFY_OK) ? 1 : 0;
153 }
154
155 void profile_munmap(unsigned long addr)
156 {
157         blocking_notifier_call_chain(&munmap_notifier, 0, (void *)addr);
158 }
159
160 int task_handoff_register(struct notifier_block *n)
161 {
162         return atomic_notifier_chain_register(&task_free_notifier, n);
163 }
164 EXPORT_SYMBOL_GPL(task_handoff_register);
165
166 int task_handoff_unregister(struct notifier_block *n)
167 {
168         return atomic_notifier_chain_unregister(&task_free_notifier, n);
169 }
170 EXPORT_SYMBOL_GPL(task_handoff_unregister);
171
172 int profile_event_register(enum profile_type type, struct notifier_block *n)
173 {
174         int err = -EINVAL;
175
176         switch (type) {
177         case PROFILE_TASK_EXIT:
178                 err = blocking_notifier_chain_register(
179                                 &task_exit_notifier, n);
180                 break;
181         case PROFILE_MUNMAP:
182                 err = blocking_notifier_chain_register(
183                                 &munmap_notifier, n);
184                 break;
185         }
186
187         return err;
188 }
189 EXPORT_SYMBOL_GPL(profile_event_register);
190
191 int profile_event_unregister(enum profile_type type, struct notifier_block *n)
192 {
193         int err = -EINVAL;
194
195         switch (type) {
196         case PROFILE_TASK_EXIT:
197                 err = blocking_notifier_chain_unregister(
198                                 &task_exit_notifier, n);
199                 break;
200         case PROFILE_MUNMAP:
201                 err = blocking_notifier_chain_unregister(
202                                 &munmap_notifier, n);
203                 break;
204         }
205
206         return err;
207 }
208 EXPORT_SYMBOL_GPL(profile_event_unregister);
209
210 int register_timer_hook(int (*hook)(struct pt_regs *))
211 {
212         if (timer_hook)
213                 return -EBUSY;
214         timer_hook = hook;
215         return 0;
216 }
217 EXPORT_SYMBOL_GPL(register_timer_hook);
218
219 void unregister_timer_hook(int (*hook)(struct pt_regs *))
220 {
221         WARN_ON(hook != timer_hook);
222         timer_hook = NULL;
223         /* make sure all CPUs see the NULL hook */
224         synchronize_sched();  /* Allow ongoing interrupts to complete. */
225 }
226 EXPORT_SYMBOL_GPL(unregister_timer_hook);
227
228
229 #ifdef CONFIG_SMP
230 /*
231  * Each cpu has a pair of open-addressed hashtables for pending
232  * profile hits. read_profile() IPI's all cpus to request them
233  * to flip buffers and flushes their contents to prof_buffer itself.
234  * Flip requests are serialized by the profile_flip_mutex. The sole
235  * use of having a second hashtable is for avoiding cacheline
236  * contention that would otherwise happen during flushes of pending
237  * profile hits required for the accuracy of reported profile hits
238  * and so resurrect the interrupt livelock issue.
239  *
240  * The open-addressed hashtables are indexed by profile buffer slot
241  * and hold the number of pending hits to that profile buffer slot on
242  * a cpu in an entry. When the hashtable overflows, all pending hits
243  * are accounted to their corresponding profile buffer slots with
244  * atomic_add() and the hashtable emptied. As numerous pending hits
245  * may be accounted to a profile buffer slot in a hashtable entry,
246  * this amortizes a number of atomic profile buffer increments likely
247  * to be far larger than the number of entries in the hashtable,
248  * particularly given that the number of distinct profile buffer
249  * positions to which hits are accounted during short intervals (e.g.
250  * several seconds) is usually very small. Exclusion from buffer
251  * flipping is provided by interrupt disablement (note that for
252  * SCHED_PROFILING or SLEEP_PROFILING profile_hit() may be called from
253  * process context).
254  * The hash function is meant to be lightweight as opposed to strong,
255  * and was vaguely inspired by ppc64 firmware-supported inverted
256  * pagetable hash functions, but uses a full hashtable full of finite
257  * collision chains, not just pairs of them.
258  *
259  * -- wli
260  */
261 static void __profile_flip_buffers(void *unused)
262 {
263         int cpu = smp_processor_id();
264
265         per_cpu(cpu_profile_flip, cpu) = !per_cpu(cpu_profile_flip, cpu);
266 }
267
268 static void profile_flip_buffers(void)
269 {
270         int i, j, cpu;
271
272         mutex_lock(&profile_flip_mutex);
273         j = per_cpu(cpu_profile_flip, get_cpu());
274         put_cpu();
275         on_each_cpu(__profile_flip_buffers, NULL, 1);
276         for_each_online_cpu(cpu) {
277                 struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[j];
278                 for (i = 0; i < NR_PROFILE_HIT; ++i) {
279                         if (!hits[i].hits) {
280                                 if (hits[i].pc)
281                                         hits[i].pc = 0;
282                                 continue;
283                         }
284                         atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
285                         hits[i].hits = hits[i].pc = 0;
286                 }
287         }
288         mutex_unlock(&profile_flip_mutex);
289 }
290
291 static void profile_discard_flip_buffers(void)
292 {
293         int i, cpu;
294
295         mutex_lock(&profile_flip_mutex);
296         i = per_cpu(cpu_profile_flip, get_cpu());
297         put_cpu();
298         on_each_cpu(__profile_flip_buffers, NULL, 1);
299         for_each_online_cpu(cpu) {
300                 struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[i];
301                 memset(hits, 0, NR_PROFILE_HIT*sizeof(struct profile_hit));
302         }
303         mutex_unlock(&profile_flip_mutex);
304 }
305
306 void profile_hits(int type, void *__pc, unsigned int nr_hits)
307 {
308         unsigned long primary, secondary, flags, pc = (unsigned long)__pc;
309         int i, j, cpu;
310         struct profile_hit *hits;
311
312         if (prof_on != type || !prof_buffer)
313                 return;
314         pc = min((pc - (unsigned long)_stext) >> prof_shift, prof_len - 1);
315         i = primary = (pc & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
316         secondary = (~(pc << 1) & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
317         cpu = get_cpu();
318         hits = per_cpu(cpu_profile_hits, cpu)[per_cpu(cpu_profile_flip, cpu)];
319         if (!hits) {
320                 put_cpu();
321                 return;
322         }
323         /*
324          * We buffer the global profiler buffer into a per-CPU
325          * queue and thus reduce the number of global (and possibly
326          * NUMA-alien) accesses. The write-queue is self-coalescing:
327          */
328         local_irq_save(flags);
329         do {
330                 for (j = 0; j < PROFILE_GRPSZ; ++j) {
331                         if (hits[i + j].pc == pc) {
332                                 hits[i + j].hits += nr_hits;
333                                 goto out;
334                         } else if (!hits[i + j].hits) {
335                                 hits[i + j].pc = pc;
336                                 hits[i + j].hits = nr_hits;
337                                 goto out;
338                         }
339                 }
340                 i = (i + secondary) & (NR_PROFILE_HIT - 1);
341         } while (i != primary);
342
343         /*
344          * Add the current hit(s) and flush the write-queue out
345          * to the global buffer:
346          */
347         atomic_add(nr_hits, &prof_buffer[pc]);
348         for (i = 0; i < NR_PROFILE_HIT; ++i) {
349                 atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
350                 hits[i].pc = hits[i].hits = 0;
351         }
352 out:
353         local_irq_restore(flags);
354         put_cpu();
355 }
356
357 static int __cpuinit profile_cpu_callback(struct notifier_block *info,
358                                         unsigned long action, void *__cpu)
359 {
360         int node, cpu = (unsigned long)__cpu;
361         struct page *page;
362
363         switch (action) {
364         case CPU_UP_PREPARE:
365         case CPU_UP_PREPARE_FROZEN:
366                 node = cpu_to_node(cpu);
367                 per_cpu(cpu_profile_flip, cpu) = 0;
368                 if (!per_cpu(cpu_profile_hits, cpu)[1]) {
369                         page = alloc_pages_exact_node(node,
370                                         GFP_KERNEL | __GFP_ZERO,
371                                         0);
372                         if (!page)
373                                 return NOTIFY_BAD;
374                         per_cpu(cpu_profile_hits, cpu)[1] = page_address(page);
375                 }
376                 if (!per_cpu(cpu_profile_hits, cpu)[0]) {
377                         page = alloc_pages_exact_node(node,
378                                         GFP_KERNEL | __GFP_ZERO,
379                                         0);
380                         if (!page)
381                                 goto out_free;
382                         per_cpu(cpu_profile_hits, cpu)[0] = page_address(page);
383                 }
384                 break;
385 out_free:
386                 page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
387                 per_cpu(cpu_profile_hits, cpu)[1] = NULL;
388                 __free_page(page);
389                 return NOTIFY_BAD;
390         case CPU_ONLINE:
391         case CPU_ONLINE_FROZEN:
392                 if (prof_cpu_mask != NULL)
393                         cpumask_set_cpu(cpu, prof_cpu_mask);
394                 break;
395         case CPU_UP_CANCELED:
396         case CPU_UP_CANCELED_FROZEN:
397         case CPU_DEAD:
398         case CPU_DEAD_FROZEN:
399                 if (prof_cpu_mask != NULL)
400                         cpumask_clear_cpu(cpu, prof_cpu_mask);
401                 if (per_cpu(cpu_profile_hits, cpu)[0]) {
402                         page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
403                         per_cpu(cpu_profile_hits, cpu)[0] = NULL;
404                         __free_page(page);
405                 }
406                 if (per_cpu(cpu_profile_hits, cpu)[1]) {
407                         page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
408                         per_cpu(cpu_profile_hits, cpu)[1] = NULL;
409                         __free_page(page);
410                 }
411                 break;
412         }
413         return NOTIFY_OK;
414 }
415 #else /* !CONFIG_SMP */
416 #define profile_flip_buffers()          do { } while (0)
417 #define profile_discard_flip_buffers()  do { } while (0)
418 #define profile_cpu_callback            NULL
419
420 void profile_hits(int type, void *__pc, unsigned int nr_hits)
421 {
422         unsigned long pc;
423
424         if (prof_on != type || !prof_buffer)
425                 return;
426         pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift;
427         atomic_add(nr_hits, &prof_buffer[min(pc, prof_len - 1)]);
428 }
429 #endif /* !CONFIG_SMP */
430 EXPORT_SYMBOL_GPL(profile_hits);
431
432 void profile_tick(int type)
433 {
434         struct pt_regs *regs = get_irq_regs();
435
436         if (type == CPU_PROFILING && timer_hook)
437                 timer_hook(regs);
438         if (!user_mode(regs) && prof_cpu_mask != NULL &&
439             cpumask_test_cpu(smp_processor_id(), prof_cpu_mask))
440                 profile_hit(type, (void *)profile_pc(regs));
441 }
442
443 #ifdef CONFIG_PROC_FS
444 #include <linux/proc_fs.h>
445 #include <linux/seq_file.h>
446 #include <asm/uaccess.h>
447
448 static int prof_cpu_mask_proc_show(struct seq_file *m, void *v)
449 {
450         seq_cpumask(m, prof_cpu_mask);
451         seq_putc(m, '\n');
452         return 0;
453 }
454
455 static int prof_cpu_mask_proc_open(struct inode *inode, struct file *file)
456 {
457         return single_open(file, prof_cpu_mask_proc_show, NULL);
458 }
459
460 static ssize_t prof_cpu_mask_proc_write(struct file *file,
461         const char __user *buffer, size_t count, loff_t *pos)
462 {
463         cpumask_var_t new_value;
464         int err;
465
466         if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
467                 return -ENOMEM;
468
469         err = cpumask_parse_user(buffer, count, new_value);
470         if (!err) {
471                 cpumask_copy(prof_cpu_mask, new_value);
472                 err = count;
473         }
474         free_cpumask_var(new_value);
475         return err;
476 }
477
478 static const struct file_operations prof_cpu_mask_proc_fops = {
479         .open           = prof_cpu_mask_proc_open,
480         .read           = seq_read,
481         .llseek         = seq_lseek,
482         .release        = single_release,
483         .write          = prof_cpu_mask_proc_write,
484 };
485
486 void create_prof_cpu_mask(struct proc_dir_entry *root_irq_dir)
487 {
488         /* create /proc/irq/prof_cpu_mask */
489         proc_create("prof_cpu_mask", 0600, root_irq_dir, &prof_cpu_mask_proc_fops);
490 }
491
492 /*
493  * This function accesses profiling information. The returned data is
494  * binary: the sampling step and the actual contents of the profile
495  * buffer. Use of the program readprofile is recommended in order to
496  * get meaningful info out of these data.
497  */
498 static ssize_t
499 read_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos)
500 {
501         unsigned long p = *ppos;
502         ssize_t read;
503         char *pnt;
504         unsigned int sample_step = 1 << prof_shift;
505
506         profile_flip_buffers();
507         if (p >= (prof_len+1)*sizeof(unsigned int))
508                 return 0;
509         if (count > (prof_len+1)*sizeof(unsigned int) - p)
510                 count = (prof_len+1)*sizeof(unsigned int) - p;
511         read = 0;
512
513         while (p < sizeof(unsigned int) && count > 0) {
514                 if (put_user(*((char *)(&sample_step)+p), buf))
515                         return -EFAULT;
516                 buf++; p++; count--; read++;
517         }
518         pnt = (char *)prof_buffer + p - sizeof(atomic_t);
519         if (copy_to_user(buf, (void *)pnt, count))
520                 return -EFAULT;
521         read += count;
522         *ppos += read;
523         return read;
524 }
525
526 /*
527  * Writing to /proc/profile resets the counters
528  *
529  * Writing a 'profiling multiplier' value into it also re-sets the profiling
530  * interrupt frequency, on architectures that support this.
531  */
532 static ssize_t write_profile(struct file *file, const char __user *buf,
533                              size_t count, loff_t *ppos)
534 {
535 #ifdef CONFIG_SMP
536         extern int setup_profiling_timer(unsigned int multiplier);
537
538         if (count == sizeof(int)) {
539                 unsigned int multiplier;
540
541                 if (copy_from_user(&multiplier, buf, sizeof(int)))
542                         return -EFAULT;
543
544                 if (setup_profiling_timer(multiplier))
545                         return -EINVAL;
546         }
547 #endif
548         profile_discard_flip_buffers();
549         memset(prof_buffer, 0, prof_len * sizeof(atomic_t));
550         return count;
551 }
552
553 static const struct file_operations proc_profile_operations = {
554         .read           = read_profile,
555         .write          = write_profile,
556 };
557
558 #ifdef CONFIG_SMP
559 static void profile_nop(void *unused)
560 {
561 }
562
563 static int create_hash_tables(void)
564 {
565         int cpu;
566
567         for_each_online_cpu(cpu) {
568                 int node = cpu_to_node(cpu);
569                 struct page *page;
570
571                 page = alloc_pages_exact_node(node,
572                                 GFP_KERNEL | __GFP_ZERO | GFP_THISNODE,
573                                 0);
574                 if (!page)
575                         goto out_cleanup;
576                 per_cpu(cpu_profile_hits, cpu)[1]
577                                 = (struct profile_hit *)page_address(page);
578                 page = alloc_pages_exact_node(node,
579                                 GFP_KERNEL | __GFP_ZERO | GFP_THISNODE,
580                                 0);
581                 if (!page)
582                         goto out_cleanup;
583                 per_cpu(cpu_profile_hits, cpu)[0]
584                                 = (struct profile_hit *)page_address(page);
585         }
586         return 0;
587 out_cleanup:
588         prof_on = 0;
589         smp_mb();
590         on_each_cpu(profile_nop, NULL, 1);
591         for_each_online_cpu(cpu) {
592                 struct page *page;
593
594                 if (per_cpu(cpu_profile_hits, cpu)[0]) {
595                         page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
596                         per_cpu(cpu_profile_hits, cpu)[0] = NULL;
597                         __free_page(page);
598                 }
599                 if (per_cpu(cpu_profile_hits, cpu)[1]) {
600                         page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
601                         per_cpu(cpu_profile_hits, cpu)[1] = NULL;
602                         __free_page(page);
603                 }
604         }
605         return -1;
606 }
607 #else
608 #define create_hash_tables()                    ({ 0; })
609 #endif
610
611 int __ref create_proc_profile(void) /* false positive from hotcpu_notifier */
612 {
613         struct proc_dir_entry *entry;
614
615         if (!prof_on)
616                 return 0;
617         if (create_hash_tables())
618                 return -ENOMEM;
619         entry = proc_create("profile", S_IWUSR | S_IRUGO,
620                             NULL, &proc_profile_operations);
621         if (!entry)
622                 return 0;
623         entry->size = (1+prof_len) * sizeof(atomic_t);
624         hotcpu_notifier(profile_cpu_callback, 0);
625         return 0;
626 }
627 module_init(create_proc_profile);
628 #endif /* CONFIG_PROC_FS */