Commit | Line | Data |
---|---|---|
1da177e4 LT |
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, | |
6d49e352 | 11 | * Nadia Yvette Chambers, Oracle, July 2004 |
1da177e4 | 12 | * Amortized hit count accounting via per-cpu open-addressed hashtables |
6d49e352 NYC |
13 | * to resolve timer interrupt livelocks, Nadia Yvette Chambers, |
14 | * Oracle, 2004 | |
1da177e4 LT |
15 | */ |
16 | ||
9984de1a | 17 | #include <linux/export.h> |
1da177e4 LT |
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> | |
1da177e4 | 24 | #include <linux/highmem.h> |
97d1f15b | 25 | #include <linux/mutex.h> |
22b8ce94 DH |
26 | #include <linux/slab.h> |
27 | #include <linux/vmalloc.h> | |
1da177e4 | 28 | #include <asm/sections.h> |
7d12e780 | 29 | #include <asm/irq_regs.h> |
e8edc6e0 | 30 | #include <asm/ptrace.h> |
1da177e4 LT |
31 | |
32 | struct 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 | ||
1da177e4 LT |
40 | static atomic_t *prof_buffer; |
41 | static unsigned long prof_len, prof_shift; | |
07031e14 | 42 | |
ece8a684 | 43 | int prof_on __read_mostly; |
07031e14 IM |
44 | EXPORT_SYMBOL_GPL(prof_on); |
45 | ||
c309b917 | 46 | static cpumask_var_t prof_cpu_mask; |
ade356b9 | 47 | #if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS) |
1da177e4 LT |
48 | static DEFINE_PER_CPU(struct profile_hit *[2], cpu_profile_hits); |
49 | static DEFINE_PER_CPU(int, cpu_profile_flip); | |
97d1f15b | 50 | static DEFINE_MUTEX(profile_flip_mutex); |
1da177e4 LT |
51 | #endif /* CONFIG_SMP */ |
52 | ||
22b8ce94 | 53 | int profile_setup(char *str) |
1da177e4 | 54 | { |
f3da64d1 FF |
55 | static const char schedstr[] = "schedule"; |
56 | static const char sleepstr[] = "sleep"; | |
57 | static const char kvmstr[] = "kvm"; | |
1da177e4 LT |
58 | int par; |
59 | ||
ece8a684 | 60 | if (!strncmp(str, sleepstr, strlen(sleepstr))) { |
b3da2a73 | 61 | #ifdef CONFIG_SCHEDSTATS |
cb251765 | 62 | force_schedstat_enabled(); |
ece8a684 IM |
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; | |
aba871f1 | 68 | pr_info("kernel sleep profiling enabled (shift: %ld)\n", |
ece8a684 | 69 | prof_shift); |
b3da2a73 | 70 | #else |
aba871f1 | 71 | pr_warn("kernel sleep profiling requires CONFIG_SCHEDSTATS\n"); |
b3da2a73 | 72 | #endif /* CONFIG_SCHEDSTATS */ |
a75acf85 | 73 | } else if (!strncmp(str, schedstr, strlen(schedstr))) { |
1da177e4 | 74 | prof_on = SCHED_PROFILING; |
dfaa9c94 WLII |
75 | if (str[strlen(schedstr)] == ',') |
76 | str += strlen(schedstr) + 1; | |
77 | if (get_option(&str, &par)) | |
78 | prof_shift = par; | |
aba871f1 | 79 | pr_info("kernel schedule profiling enabled (shift: %ld)\n", |
dfaa9c94 | 80 | prof_shift); |
07031e14 IM |
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; | |
aba871f1 | 87 | pr_info("kernel KVM profiling enabled (shift: %ld)\n", |
07031e14 | 88 | prof_shift); |
dfaa9c94 | 89 | } else if (get_option(&str, &par)) { |
1da177e4 LT |
90 | prof_shift = par; |
91 | prof_on = CPU_PROFILING; | |
aba871f1 | 92 | pr_info("kernel profiling enabled (shift: %ld)\n", |
1da177e4 LT |
93 | prof_shift); |
94 | } | |
95 | return 1; | |
96 | } | |
97 | __setup("profile=", profile_setup); | |
98 | ||
99 | ||
ce05fcc3 | 100 | int __ref profile_init(void) |
1da177e4 | 101 | { |
22b8ce94 | 102 | int buffer_bytes; |
1ad82fd5 | 103 | if (!prof_on) |
22b8ce94 | 104 | return 0; |
1ad82fd5 | 105 | |
1da177e4 LT |
106 | /* only text is profiled */ |
107 | prof_len = (_etext - _stext) >> prof_shift; | |
22b8ce94 | 108 | buffer_bytes = prof_len*sizeof(atomic_t); |
22b8ce94 | 109 | |
c309b917 RR |
110 | if (!alloc_cpumask_var(&prof_cpu_mask, GFP_KERNEL)) |
111 | return -ENOMEM; | |
112 | ||
acd89579 HD |
113 | cpumask_copy(prof_cpu_mask, cpu_possible_mask); |
114 | ||
b62f495d | 115 | prof_buffer = kzalloc(buffer_bytes, GFP_KERNEL|__GFP_NOWARN); |
22b8ce94 DH |
116 | if (prof_buffer) |
117 | return 0; | |
118 | ||
b62f495d MG |
119 | prof_buffer = alloc_pages_exact(buffer_bytes, |
120 | GFP_KERNEL|__GFP_ZERO|__GFP_NOWARN); | |
22b8ce94 DH |
121 | if (prof_buffer) |
122 | return 0; | |
123 | ||
559fa6e7 JJ |
124 | prof_buffer = vzalloc(buffer_bytes); |
125 | if (prof_buffer) | |
22b8ce94 DH |
126 | return 0; |
127 | ||
c309b917 | 128 | free_cpumask_var(prof_cpu_mask); |
22b8ce94 | 129 | return -ENOMEM; |
1da177e4 LT |
130 | } |
131 | ||
132 | /* Profile event notifications */ | |
1ad82fd5 | 133 | |
e041c683 AS |
134 | static BLOCKING_NOTIFIER_HEAD(task_exit_notifier); |
135 | static ATOMIC_NOTIFIER_HEAD(task_free_notifier); | |
136 | static BLOCKING_NOTIFIER_HEAD(munmap_notifier); | |
1ad82fd5 PC |
137 | |
138 | void profile_task_exit(struct task_struct *task) | |
1da177e4 | 139 | { |
e041c683 | 140 | blocking_notifier_call_chain(&task_exit_notifier, 0, task); |
1da177e4 | 141 | } |
1ad82fd5 PC |
142 | |
143 | int profile_handoff_task(struct task_struct *task) | |
1da177e4 LT |
144 | { |
145 | int ret; | |
e041c683 | 146 | ret = atomic_notifier_call_chain(&task_free_notifier, 0, task); |
1da177e4 LT |
147 | return (ret == NOTIFY_OK) ? 1 : 0; |
148 | } | |
149 | ||
150 | void profile_munmap(unsigned long addr) | |
151 | { | |
e041c683 | 152 | blocking_notifier_call_chain(&munmap_notifier, 0, (void *)addr); |
1da177e4 LT |
153 | } |
154 | ||
1ad82fd5 | 155 | int task_handoff_register(struct notifier_block *n) |
1da177e4 | 156 | { |
e041c683 | 157 | return atomic_notifier_chain_register(&task_free_notifier, n); |
1da177e4 | 158 | } |
1ad82fd5 | 159 | EXPORT_SYMBOL_GPL(task_handoff_register); |
1da177e4 | 160 | |
1ad82fd5 | 161 | int task_handoff_unregister(struct notifier_block *n) |
1da177e4 | 162 | { |
e041c683 | 163 | return atomic_notifier_chain_unregister(&task_free_notifier, n); |
1da177e4 | 164 | } |
1ad82fd5 | 165 | EXPORT_SYMBOL_GPL(task_handoff_unregister); |
1da177e4 | 166 | |
1ad82fd5 | 167 | int profile_event_register(enum profile_type type, struct notifier_block *n) |
1da177e4 LT |
168 | { |
169 | int err = -EINVAL; | |
1ad82fd5 | 170 | |
1da177e4 | 171 | switch (type) { |
1ad82fd5 PC |
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; | |
1da177e4 | 180 | } |
1ad82fd5 | 181 | |
1da177e4 LT |
182 | return err; |
183 | } | |
1ad82fd5 | 184 | EXPORT_SYMBOL_GPL(profile_event_register); |
1da177e4 | 185 | |
1ad82fd5 | 186 | int profile_event_unregister(enum profile_type type, struct notifier_block *n) |
1da177e4 LT |
187 | { |
188 | int err = -EINVAL; | |
1ad82fd5 | 189 | |
1da177e4 | 190 | switch (type) { |
1ad82fd5 PC |
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; | |
1da177e4 LT |
199 | } |
200 | ||
1da177e4 LT |
201 | return err; |
202 | } | |
1ad82fd5 | 203 | EXPORT_SYMBOL_GPL(profile_event_unregister); |
1da177e4 | 204 | |
ade356b9 | 205 | #if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS) |
1da177e4 LT |
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 | |
ece8a684 IM |
228 | * SCHED_PROFILING or SLEEP_PROFILING profile_hit() may be called from |
229 | * process context). | |
1da177e4 LT |
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 | * | |
6d49e352 | 235 | * -- nyc |
1da177e4 LT |
236 | */ |
237 | static 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 | ||
244 | static void profile_flip_buffers(void) | |
245 | { | |
246 | int i, j, cpu; | |
247 | ||
97d1f15b | 248 | mutex_lock(&profile_flip_mutex); |
1da177e4 LT |
249 | j = per_cpu(cpu_profile_flip, get_cpu()); |
250 | put_cpu(); | |
15c8b6c1 | 251 | on_each_cpu(__profile_flip_buffers, NULL, 1); |
1da177e4 LT |
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 | } | |
97d1f15b | 264 | mutex_unlock(&profile_flip_mutex); |
1da177e4 LT |
265 | } |
266 | ||
267 | static void profile_discard_flip_buffers(void) | |
268 | { | |
269 | int i, cpu; | |
270 | ||
97d1f15b | 271 | mutex_lock(&profile_flip_mutex); |
1da177e4 LT |
272 | i = per_cpu(cpu_profile_flip, get_cpu()); |
273 | put_cpu(); | |
15c8b6c1 | 274 | on_each_cpu(__profile_flip_buffers, NULL, 1); |
1da177e4 LT |
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 | } | |
97d1f15b | 279 | mutex_unlock(&profile_flip_mutex); |
1da177e4 LT |
280 | } |
281 | ||
6f7bd76f | 282 | static void do_profile_hits(int type, void *__pc, unsigned int nr_hits) |
1da177e4 LT |
283 | { |
284 | unsigned long primary, secondary, flags, pc = (unsigned long)__pc; | |
285 | int i, j, cpu; | |
286 | struct profile_hit *hits; | |
287 | ||
1da177e4 LT |
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 | } | |
ece8a684 IM |
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 | */ | |
1da177e4 LT |
302 | local_irq_save(flags); |
303 | do { | |
304 | for (j = 0; j < PROFILE_GRPSZ; ++j) { | |
305 | if (hits[i + j].pc == pc) { | |
ece8a684 | 306 | hits[i + j].hits += nr_hits; |
1da177e4 LT |
307 | goto out; |
308 | } else if (!hits[i + j].hits) { | |
309 | hits[i + j].pc = pc; | |
ece8a684 | 310 | hits[i + j].hits = nr_hits; |
1da177e4 LT |
311 | goto out; |
312 | } | |
313 | } | |
314 | i = (i + secondary) & (NR_PROFILE_HIT - 1); | |
315 | } while (i != primary); | |
ece8a684 IM |
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]); | |
1da177e4 LT |
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 | } | |
326 | out: | |
327 | local_irq_restore(flags); | |
328 | put_cpu(); | |
329 | } | |
330 | ||
e722d8da | 331 | static int profile_dead_cpu(unsigned int cpu) |
1da177e4 | 332 | { |
1da177e4 | 333 | struct page *page; |
e722d8da | 334 | int i; |
1da177e4 | 335 | |
e722d8da SAS |
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; | |
1da177e4 LT |
343 | __free_page(page); |
344 | } | |
e722d8da SAS |
345 | } |
346 | return 0; | |
347 | } | |
348 | ||
349 | static 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; | |
1da177e4 | 364 | } |
e722d8da SAS |
365 | per_cpu(cpu_profile_hits, cpu)[i] = page_address(page); |
366 | ||
1da177e4 | 367 | } |
e722d8da SAS |
368 | return 0; |
369 | } | |
370 | ||
371 | static 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; | |
1da177e4 | 377 | } |
e722d8da | 378 | |
1da177e4 LT |
379 | #else /* !CONFIG_SMP */ |
380 | #define profile_flip_buffers() do { } while (0) | |
381 | #define profile_discard_flip_buffers() do { } while (0) | |
382 | ||
6f7bd76f | 383 | static void do_profile_hits(int type, void *__pc, unsigned int nr_hits) |
1da177e4 LT |
384 | { |
385 | unsigned long pc; | |
1da177e4 | 386 | pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift; |
ece8a684 | 387 | atomic_add(nr_hits, &prof_buffer[min(pc, prof_len - 1)]); |
1da177e4 LT |
388 | } |
389 | #endif /* !CONFIG_SMP */ | |
6f7bd76f RM |
390 | |
391 | void 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 | } | |
bbe1a59b AM |
397 | EXPORT_SYMBOL_GPL(profile_hits); |
398 | ||
7d12e780 | 399 | void profile_tick(int type) |
1da177e4 | 400 | { |
7d12e780 DH |
401 | struct pt_regs *regs = get_irq_regs(); |
402 | ||
c309b917 RR |
403 | if (!user_mode(regs) && prof_cpu_mask != NULL && |
404 | cpumask_test_cpu(smp_processor_id(), prof_cpu_mask)) | |
1da177e4 LT |
405 | profile_hit(type, (void *)profile_pc(regs)); |
406 | } | |
407 | ||
408 | #ifdef CONFIG_PROC_FS | |
409 | #include <linux/proc_fs.h> | |
583a22e7 | 410 | #include <linux/seq_file.h> |
1da177e4 | 411 | #include <asm/uaccess.h> |
1da177e4 | 412 | |
583a22e7 | 413 | static int prof_cpu_mask_proc_show(struct seq_file *m, void *v) |
1da177e4 | 414 | { |
ccbd59c1 | 415 | seq_printf(m, "%*pb\n", cpumask_pr_args(prof_cpu_mask)); |
583a22e7 AD |
416 | return 0; |
417 | } | |
418 | ||
419 | static int prof_cpu_mask_proc_open(struct inode *inode, struct file *file) | |
420 | { | |
421 | return single_open(file, prof_cpu_mask_proc_show, NULL); | |
1da177e4 LT |
422 | } |
423 | ||
583a22e7 AD |
424 | static ssize_t prof_cpu_mask_proc_write(struct file *file, |
425 | const char __user *buffer, size_t count, loff_t *pos) | |
1da177e4 | 426 | { |
c309b917 | 427 | cpumask_var_t new_value; |
583a22e7 | 428 | int err; |
1da177e4 | 429 | |
c309b917 RR |
430 | if (!alloc_cpumask_var(&new_value, GFP_KERNEL)) |
431 | return -ENOMEM; | |
1da177e4 | 432 | |
c309b917 RR |
433 | err = cpumask_parse_user(buffer, count, new_value); |
434 | if (!err) { | |
583a22e7 AD |
435 | cpumask_copy(prof_cpu_mask, new_value); |
436 | err = count; | |
c309b917 RR |
437 | } |
438 | free_cpumask_var(new_value); | |
439 | return err; | |
1da177e4 LT |
440 | } |
441 | ||
583a22e7 AD |
442 | static 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 | ||
fbd387ae | 450 | void create_prof_cpu_mask(void) |
1da177e4 | 451 | { |
1da177e4 | 452 | /* create /proc/irq/prof_cpu_mask */ |
fbd387ae | 453 | proc_create("irq/prof_cpu_mask", 0600, NULL, &prof_cpu_mask_proc_fops); |
1da177e4 LT |
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 | */ | |
462 | static ssize_t | |
463 | read_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
464 | { | |
465 | unsigned long p = *ppos; | |
466 | ssize_t read; | |
1ad82fd5 | 467 | char *pnt; |
1da177e4 LT |
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) { | |
1ad82fd5 | 478 | if (put_user(*((char *)(&sample_step)+p), buf)) |
064b022c | 479 | return -EFAULT; |
1da177e4 LT |
480 | buf++; p++; count--; read++; |
481 | } | |
482 | pnt = (char *)prof_buffer + p - sizeof(atomic_t); | |
1ad82fd5 | 483 | if (copy_to_user(buf, (void *)pnt, count)) |
1da177e4 LT |
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 | */ | |
496 | static ssize_t write_profile(struct file *file, const char __user *buf, | |
497 | size_t count, loff_t *ppos) | |
498 | { | |
499 | #ifdef CONFIG_SMP | |
1ad82fd5 | 500 | extern int setup_profiling_timer(unsigned int multiplier); |
1da177e4 LT |
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 | ||
15ad7cdc | 517 | static const struct file_operations proc_profile_operations = { |
1da177e4 LT |
518 | .read = read_profile, |
519 | .write = write_profile, | |
6038f373 | 520 | .llseek = default_llseek, |
1da177e4 LT |
521 | }; |
522 | ||
e722d8da | 523 | int __ref create_proc_profile(void) |
1da177e4 | 524 | { |
e722d8da SAS |
525 | struct proc_dir_entry *entry; |
526 | #ifdef CONFIG_SMP | |
527 | enum cpuhp_state online_state; | |
1da177e4 LT |
528 | #endif |
529 | ||
c270a817 | 530 | int err = 0; |
1da177e4 LT |
531 | |
532 | if (!prof_on) | |
533 | return 0; | |
e722d8da SAS |
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 | |
c33fff0a DL |
547 | entry = proc_create("profile", S_IWUSR | S_IRUGO, |
548 | NULL, &proc_profile_operations); | |
1ad82fd5 | 549 | if (!entry) |
e722d8da | 550 | goto err_state_onl; |
271a15ea | 551 | proc_set_size(entry, (1 + prof_len) * sizeof(atomic_t)); |
c270a817 | 552 | |
e722d8da SAS |
553 | return err; |
554 | err_state_onl: | |
555 | #ifdef CONFIG_SMP | |
556 | cpuhp_remove_state(online_state); | |
557 | err_state_prep: | |
558 | cpuhp_remove_state(CPUHP_PROFILE_PREPARE); | |
559 | #endif | |
c270a817 | 560 | return err; |
1da177e4 | 561 | } |
c96d6660 | 562 | subsys_initcall(create_proc_profile); |
1da177e4 | 563 | #endif /* CONFIG_PROC_FS */ |