Commit | Line | Data |
---|---|---|
8e86e015 | 1 | // SPDX-License-Identifier: GPL-2.0 |
76369139 FW |
2 | /* |
3 | * Performance events ring-buffer code: | |
4 | * | |
5 | * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de> | |
6 | * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar | |
90eec103 | 7 | * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra |
d36b6910 | 8 | * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com> |
76369139 FW |
9 | */ |
10 | ||
11 | #include <linux/perf_event.h> | |
12 | #include <linux/vmalloc.h> | |
13 | #include <linux/slab.h> | |
26c86da8 | 14 | #include <linux/circ_buf.h> |
7c60fc0e | 15 | #include <linux/poll.h> |
4411ec1d | 16 | #include <linux/nospec.h> |
76369139 FW |
17 | |
18 | #include "internal.h" | |
19 | ||
76369139 FW |
20 | static void perf_output_wakeup(struct perf_output_handle *handle) |
21 | { | |
a9a08845 | 22 | atomic_set(&handle->rb->poll, EPOLLIN); |
76369139 | 23 | |
a8b0ca17 | 24 | handle->event->pending_wakeup = 1; |
ca6c2132 | 25 | irq_work_queue(&handle->event->pending_irq); |
76369139 FW |
26 | } |
27 | ||
28 | /* | |
29 | * We need to ensure a later event_id doesn't publish a head when a former | |
30 | * event isn't done writing. However since we need to deal with NMIs we | |
31 | * cannot fully serialize things. | |
32 | * | |
33 | * We only publish the head (and generate a wakeup) when the outer-most | |
34 | * event completes. | |
35 | */ | |
36 | static void perf_output_get_handle(struct perf_output_handle *handle) | |
37 | { | |
56de4e8f | 38 | struct perf_buffer *rb = handle->rb; |
76369139 FW |
39 | |
40 | preempt_disable(); | |
5322ea58 PZ |
41 | |
42 | /* | |
43 | * Avoid an explicit LOAD/STORE such that architectures with memops | |
44 | * can use them. | |
45 | */ | |
46 | (*(volatile unsigned int *)&rb->nest)++; | |
76369139 FW |
47 | handle->wakeup = local_read(&rb->wakeup); |
48 | } | |
49 | ||
50 | static void perf_output_put_handle(struct perf_output_handle *handle) | |
51 | { | |
56de4e8f | 52 | struct perf_buffer *rb = handle->rb; |
76369139 | 53 | unsigned long head; |
5322ea58 PZ |
54 | unsigned int nest; |
55 | ||
56 | /* | |
57 | * If this isn't the outermost nesting, we don't have to update | |
58 | * @rb->user_page->data_head. | |
59 | */ | |
60 | nest = READ_ONCE(rb->nest); | |
61 | if (nest > 1) { | |
62 | WRITE_ONCE(rb->nest, nest - 1); | |
63 | goto out; | |
64 | } | |
76369139 FW |
65 | |
66 | again: | |
3f9fbe9b PZ |
67 | /* |
68 | * In order to avoid publishing a head value that goes backwards, | |
69 | * we must ensure the load of @rb->head happens after we've | |
70 | * incremented @rb->nest. | |
71 | * | |
72 | * Otherwise we can observe a @rb->head value before one published | |
73 | * by an IRQ/NMI happening between the load and the increment. | |
74 | */ | |
75 | barrier(); | |
76369139 FW |
76 | head = local_read(&rb->head); |
77 | ||
78 | /* | |
1b038c6e YC |
79 | * IRQ/NMI can happen here and advance @rb->head, causing our |
80 | * load above to be stale. | |
76369139 FW |
81 | */ |
82 | ||
76369139 | 83 | /* |
bf378d34 PZ |
84 | * Since the mmap() consumer (userspace) can run on a different CPU: |
85 | * | |
86 | * kernel user | |
87 | * | |
c7f2e3cd PZ |
88 | * if (LOAD ->data_tail) { LOAD ->data_head |
89 | * (A) smp_rmb() (C) | |
90 | * STORE $data LOAD $data | |
91 | * smp_wmb() (B) smp_mb() (D) | |
92 | * STORE ->data_head STORE ->data_tail | |
93 | * } | |
bf378d34 PZ |
94 | * |
95 | * Where A pairs with D, and B pairs with C. | |
96 | * | |
c7f2e3cd PZ |
97 | * In our case (A) is a control dependency that separates the load of |
98 | * the ->data_tail and the stores of $data. In case ->data_tail | |
99 | * indicates there is no room in the buffer to store $data we do not. | |
bf378d34 | 100 | * |
c7f2e3cd | 101 | * D needs to be a full barrier since it separates the data READ |
bf378d34 PZ |
102 | * from the tail WRITE. |
103 | * | |
104 | * For B a WMB is sufficient since it separates two WRITEs, and for C | |
105 | * an RMB is sufficient since it separates two READs. | |
106 | * | |
107 | * See perf_output_begin(). | |
76369139 | 108 | */ |
c7f2e3cd | 109 | smp_wmb(); /* B, matches C */ |
4d839dd9 | 110 | WRITE_ONCE(rb->user_page->data_head, head); |
76369139 FW |
111 | |
112 | /* | |
1b038c6e YC |
113 | * We must publish the head before decrementing the nest count, |
114 | * otherwise an IRQ/NMI can publish a more recent head value and our | |
115 | * write will (temporarily) publish a stale value. | |
116 | */ | |
117 | barrier(); | |
5322ea58 | 118 | WRITE_ONCE(rb->nest, 0); |
1b038c6e YC |
119 | |
120 | /* | |
121 | * Ensure we decrement @rb->nest before we validate the @rb->head. | |
122 | * Otherwise we cannot be sure we caught the 'last' nested update. | |
76369139 | 123 | */ |
1b038c6e | 124 | barrier(); |
76369139 | 125 | if (unlikely(head != local_read(&rb->head))) { |
5322ea58 | 126 | WRITE_ONCE(rb->nest, 1); |
76369139 FW |
127 | goto again; |
128 | } | |
129 | ||
130 | if (handle->wakeup != local_read(&rb->wakeup)) | |
131 | perf_output_wakeup(handle); | |
132 | ||
133 | out: | |
134 | preempt_enable(); | |
135 | } | |
136 | ||
57d6a793 | 137 | static __always_inline bool |
d1b26c70 WN |
138 | ring_buffer_has_space(unsigned long head, unsigned long tail, |
139 | unsigned long data_size, unsigned int size, | |
140 | bool backward) | |
141 | { | |
142 | if (!backward) | |
143 | return CIRC_SPACE(head, tail, data_size) >= size; | |
144 | else | |
145 | return CIRC_SPACE(tail, head, data_size) >= size; | |
146 | } | |
147 | ||
57d6a793 | 148 | static __always_inline int |
d1b26c70 | 149 | __perf_output_begin(struct perf_output_handle *handle, |
267fb273 | 150 | struct perf_sample_data *data, |
d1b26c70 WN |
151 | struct perf_event *event, unsigned int size, |
152 | bool backward) | |
76369139 | 153 | { |
56de4e8f | 154 | struct perf_buffer *rb; |
76369139 | 155 | unsigned long tail, offset, head; |
524feca5 | 156 | int have_lost, page_shift; |
76369139 FW |
157 | struct { |
158 | struct perf_event_header header; | |
159 | u64 id; | |
160 | u64 lost; | |
161 | } lost_event; | |
162 | ||
163 | rcu_read_lock(); | |
164 | /* | |
165 | * For inherited events we send all the output towards the parent. | |
166 | */ | |
167 | if (event->parent) | |
168 | event = event->parent; | |
169 | ||
170 | rb = rcu_dereference(event->rb); | |
c72b42a3 | 171 | if (unlikely(!rb)) |
76369139 FW |
172 | goto out; |
173 | ||
86e7972f | 174 | if (unlikely(rb->paused)) { |
119a784c | 175 | if (rb->nr_pages) { |
86e7972f | 176 | local_inc(&rb->lost); |
119a784c NK |
177 | atomic64_inc(&event->lost_samples); |
178 | } | |
76369139 | 179 | goto out; |
86e7972f | 180 | } |
76369139 | 181 | |
c72b42a3 PZ |
182 | handle->rb = rb; |
183 | handle->event = event; | |
184 | ||
76369139 | 185 | have_lost = local_read(&rb->lost); |
c72b42a3 | 186 | if (unlikely(have_lost)) { |
d20a973f PZ |
187 | size += sizeof(lost_event); |
188 | if (event->attr.sample_id_all) | |
189 | size += event->id_header_size; | |
76369139 FW |
190 | } |
191 | ||
192 | perf_output_get_handle(handle); | |
193 | ||
1af61adb | 194 | offset = local_read(&rb->head); |
76369139 | 195 | do { |
1af61adb | 196 | head = offset; |
105ff3cb | 197 | tail = READ_ONCE(rb->user_page->data_tail); |
d1b26c70 WN |
198 | if (!rb->overwrite) { |
199 | if (unlikely(!ring_buffer_has_space(head, tail, | |
200 | perf_data_size(rb), | |
201 | size, backward))) | |
202 | goto fail; | |
203 | } | |
c7f2e3cd PZ |
204 | |
205 | /* | |
206 | * The above forms a control dependency barrier separating the | |
207 | * @tail load above from the data stores below. Since the @tail | |
208 | * load is required to compute the branch to fail below. | |
209 | * | |
210 | * A, matches D; the full memory barrier userspace SHOULD issue | |
211 | * after reading the data and before storing the new tail | |
212 | * position. | |
213 | * | |
214 | * See perf_output_put_handle(). | |
215 | */ | |
216 | ||
d1b26c70 WN |
217 | if (!backward) |
218 | head += size; | |
219 | else | |
220 | head -= size; | |
1af61adb | 221 | } while (!local_try_cmpxchg(&rb->head, &offset, head)); |
76369139 | 222 | |
d1b26c70 WN |
223 | if (backward) { |
224 | offset = head; | |
225 | head = (u64)(-head); | |
226 | } | |
227 | ||
85f59edf | 228 | /* |
c7f2e3cd PZ |
229 | * We rely on the implied barrier() by local_cmpxchg() to ensure |
230 | * none of the data stores below can be lifted up by the compiler. | |
85f59edf | 231 | */ |
85f59edf | 232 | |
c72b42a3 | 233 | if (unlikely(head - local_read(&rb->wakeup) > rb->watermark)) |
76369139 FW |
234 | local_add(rb->watermark, &rb->wakeup); |
235 | ||
524feca5 PZ |
236 | page_shift = PAGE_SHIFT + page_order(rb); |
237 | ||
238 | handle->page = (offset >> page_shift) & (rb->nr_pages - 1); | |
239 | offset &= (1UL << page_shift) - 1; | |
240 | handle->addr = rb->data_pages[handle->page] + offset; | |
241 | handle->size = (1UL << page_shift) - offset; | |
76369139 | 242 | |
c72b42a3 | 243 | if (unlikely(have_lost)) { |
d20a973f | 244 | lost_event.header.size = sizeof(lost_event); |
76369139 FW |
245 | lost_event.header.type = PERF_RECORD_LOST; |
246 | lost_event.header.misc = 0; | |
247 | lost_event.id = event->id; | |
248 | lost_event.lost = local_xchg(&rb->lost, 0); | |
249 | ||
267fb273 PZ |
250 | /* XXX mostly redundant; @data is already fully initializes */ |
251 | perf_event_header__init_id(&lost_event.header, data, event); | |
76369139 | 252 | perf_output_put(handle, lost_event); |
267fb273 | 253 | perf_event__output_id_sample(event, handle, data); |
76369139 FW |
254 | } |
255 | ||
256 | return 0; | |
257 | ||
258 | fail: | |
259 | local_inc(&rb->lost); | |
119a784c | 260 | atomic64_inc(&event->lost_samples); |
76369139 FW |
261 | perf_output_put_handle(handle); |
262 | out: | |
263 | rcu_read_unlock(); | |
264 | ||
265 | return -ENOSPC; | |
266 | } | |
267 | ||
9ecda41a | 268 | int perf_output_begin_forward(struct perf_output_handle *handle, |
267fb273 PZ |
269 | struct perf_sample_data *data, |
270 | struct perf_event *event, unsigned int size) | |
9ecda41a | 271 | { |
267fb273 | 272 | return __perf_output_begin(handle, data, event, size, false); |
9ecda41a WN |
273 | } |
274 | ||
275 | int perf_output_begin_backward(struct perf_output_handle *handle, | |
267fb273 | 276 | struct perf_sample_data *data, |
9ecda41a WN |
277 | struct perf_event *event, unsigned int size) |
278 | { | |
267fb273 | 279 | return __perf_output_begin(handle, data, event, size, true); |
9ecda41a WN |
280 | } |
281 | ||
d1b26c70 | 282 | int perf_output_begin(struct perf_output_handle *handle, |
267fb273 | 283 | struct perf_sample_data *data, |
d1b26c70 WN |
284 | struct perf_event *event, unsigned int size) |
285 | { | |
9ecda41a | 286 | |
267fb273 | 287 | return __perf_output_begin(handle, data, event, size, |
9ecda41a | 288 | unlikely(is_write_backward(event))); |
d1b26c70 WN |
289 | } |
290 | ||
91d7753a | 291 | unsigned int perf_output_copy(struct perf_output_handle *handle, |
76369139 FW |
292 | const void *buf, unsigned int len) |
293 | { | |
91d7753a | 294 | return __output_copy(handle, buf, len); |
76369139 FW |
295 | } |
296 | ||
5685e0ff JO |
297 | unsigned int perf_output_skip(struct perf_output_handle *handle, |
298 | unsigned int len) | |
299 | { | |
300 | return __output_skip(handle, NULL, len); | |
301 | } | |
302 | ||
76369139 FW |
303 | void perf_output_end(struct perf_output_handle *handle) |
304 | { | |
76369139 FW |
305 | perf_output_put_handle(handle); |
306 | rcu_read_unlock(); | |
307 | } | |
308 | ||
309 | static void | |
56de4e8f | 310 | ring_buffer_init(struct perf_buffer *rb, long watermark, int flags) |
76369139 FW |
311 | { |
312 | long max_size = perf_data_size(rb); | |
313 | ||
314 | if (watermark) | |
315 | rb->watermark = min(max_size, watermark); | |
316 | ||
317 | if (!rb->watermark) | |
318 | rb->watermark = max_size / 2; | |
319 | ||
320 | if (flags & RING_BUFFER_WRITABLE) | |
dd9c086d SE |
321 | rb->overwrite = 0; |
322 | else | |
323 | rb->overwrite = 1; | |
76369139 | 324 | |
fecb8ed2 | 325 | refcount_set(&rb->refcount, 1); |
10c6db11 PZ |
326 | |
327 | INIT_LIST_HEAD(&rb->event_list); | |
328 | spin_lock_init(&rb->event_lock); | |
86e7972f WN |
329 | |
330 | /* | |
331 | * perf_output_begin() only checks rb->paused, therefore | |
332 | * rb->paused must be true if we have no pages for output. | |
333 | */ | |
334 | if (!rb->nr_pages) | |
335 | rb->paused = 1; | |
76369139 FW |
336 | } |
337 | ||
f4c0b0aa WD |
338 | void perf_aux_output_flag(struct perf_output_handle *handle, u64 flags) |
339 | { | |
340 | /* | |
341 | * OVERWRITE is determined by perf_aux_output_end() and can't | |
342 | * be passed in directly. | |
343 | */ | |
344 | if (WARN_ON_ONCE(flags & PERF_AUX_FLAG_OVERWRITE)) | |
345 | return; | |
346 | ||
347 | handle->aux_flags |= flags; | |
348 | } | |
349 | EXPORT_SYMBOL_GPL(perf_aux_output_flag); | |
350 | ||
fdc26706 AS |
351 | /* |
352 | * This is called before hardware starts writing to the AUX area to | |
353 | * obtain an output handle and make sure there's room in the buffer. | |
354 | * When the capture completes, call perf_aux_output_end() to commit | |
355 | * the recorded data to the buffer. | |
356 | * | |
357 | * The ordering is similar to that of perf_output_{begin,end}, with | |
358 | * the exception of (B), which should be taken care of by the pmu | |
359 | * driver, since ordering rules will differ depending on hardware. | |
af5bb4ed AS |
360 | * |
361 | * Call this from pmu::start(); see the comment in perf_aux_output_end() | |
362 | * about its use in pmu callbacks. Both can also be called from the PMI | |
363 | * handler if needed. | |
fdc26706 AS |
364 | */ |
365 | void *perf_aux_output_begin(struct perf_output_handle *handle, | |
366 | struct perf_event *event) | |
367 | { | |
368 | struct perf_event *output_event = event; | |
369 | unsigned long aux_head, aux_tail; | |
56de4e8f | 370 | struct perf_buffer *rb; |
5322ea58 | 371 | unsigned int nest; |
fdc26706 AS |
372 | |
373 | if (output_event->parent) | |
374 | output_event = output_event->parent; | |
375 | ||
376 | /* | |
377 | * Since this will typically be open across pmu::add/pmu::del, we | |
378 | * grab ring_buffer's refcount instead of holding rcu read lock | |
379 | * to make sure it doesn't disappear under us. | |
380 | */ | |
381 | rb = ring_buffer_get(output_event); | |
382 | if (!rb) | |
383 | return NULL; | |
384 | ||
b79ccadd | 385 | if (!rb_has_aux(rb)) |
fdc26706 AS |
386 | goto err; |
387 | ||
dcb10a96 | 388 | /* |
b79ccadd AS |
389 | * If aux_mmap_count is zero, the aux buffer is in perf_mmap_close(), |
390 | * about to get freed, so we leave immediately. | |
391 | * | |
392 | * Checking rb::aux_mmap_count and rb::refcount has to be done in | |
393 | * the same order, see perf_mmap_close. Otherwise we end up freeing | |
394 | * aux pages in this path, which is a bug, because in_atomic(). | |
dcb10a96 AS |
395 | */ |
396 | if (!atomic_read(&rb->aux_mmap_count)) | |
b79ccadd AS |
397 | goto err; |
398 | ||
ca3bb3d0 | 399 | if (!refcount_inc_not_zero(&rb->aux_refcount)) |
b79ccadd | 400 | goto err; |
dcb10a96 | 401 | |
5322ea58 | 402 | nest = READ_ONCE(rb->aux_nest); |
fdc26706 AS |
403 | /* |
404 | * Nesting is not supported for AUX area, make sure nested | |
405 | * writers are caught early | |
406 | */ | |
5322ea58 | 407 | if (WARN_ON_ONCE(nest)) |
fdc26706 AS |
408 | goto err_put; |
409 | ||
5322ea58 PZ |
410 | WRITE_ONCE(rb->aux_nest, nest + 1); |
411 | ||
2ab346cf | 412 | aux_head = rb->aux_head; |
fdc26706 AS |
413 | |
414 | handle->rb = rb; | |
415 | handle->event = event; | |
416 | handle->head = aux_head; | |
2023a0d2 | 417 | handle->size = 0; |
f4c0b0aa | 418 | handle->aux_flags = 0; |
fdc26706 AS |
419 | |
420 | /* | |
2023a0d2 AS |
421 | * In overwrite mode, AUX data stores do not depend on aux_tail, |
422 | * therefore (A) control dependency barrier does not exist. The | |
423 | * (B) <-> (C) ordering is still observed by the pmu driver. | |
fdc26706 | 424 | */ |
2023a0d2 | 425 | if (!rb->aux_overwrite) { |
6aa7de05 | 426 | aux_tail = READ_ONCE(rb->user_page->aux_tail); |
2ab346cf | 427 | handle->wakeup = rb->aux_wakeup + rb->aux_watermark; |
2023a0d2 AS |
428 | if (aux_head - aux_tail < perf_aux_size(rb)) |
429 | handle->size = CIRC_SPACE(aux_head, aux_tail, perf_aux_size(rb)); | |
430 | ||
431 | /* | |
432 | * handle->size computation depends on aux_tail load; this forms a | |
433 | * control dependency barrier separating aux_tail load from aux data | |
434 | * store that will be enabled on successful return | |
435 | */ | |
436 | if (!handle->size) { /* A, matches D */ | |
1d54ad94 | 437 | event->pending_disable = smp_processor_id(); |
2023a0d2 | 438 | perf_output_wakeup(handle); |
5322ea58 | 439 | WRITE_ONCE(rb->aux_nest, 0); |
2023a0d2 AS |
440 | goto err_put; |
441 | } | |
fdc26706 AS |
442 | } |
443 | ||
444 | return handle->rb->aux_priv; | |
445 | ||
446 | err_put: | |
af5bb4ed | 447 | /* can't be last */ |
fdc26706 AS |
448 | rb_free_aux(rb); |
449 | ||
450 | err: | |
95ff4ca2 | 451 | ring_buffer_put(rb); |
fdc26706 AS |
452 | handle->event = NULL; |
453 | ||
454 | return NULL; | |
455 | } | |
bc1d2020 | 456 | EXPORT_SYMBOL_GPL(perf_aux_output_begin); |
fdc26706 | 457 | |
56de4e8f | 458 | static __always_inline bool rb_need_aux_wakeup(struct perf_buffer *rb) |
441430eb AS |
459 | { |
460 | if (rb->aux_overwrite) | |
461 | return false; | |
462 | ||
463 | if (rb->aux_head - rb->aux_wakeup >= rb->aux_watermark) { | |
464 | rb->aux_wakeup = rounddown(rb->aux_head, rb->aux_watermark); | |
465 | return true; | |
466 | } | |
467 | ||
468 | return false; | |
469 | } | |
470 | ||
fdc26706 AS |
471 | /* |
472 | * Commit the data written by hardware into the ring buffer by adjusting | |
473 | * aux_head and posting a PERF_RECORD_AUX into the perf buffer. It is the | |
474 | * pmu driver's responsibility to observe ordering rules of the hardware, | |
475 | * so that all the data is externally visible before this is called. | |
af5bb4ed AS |
476 | * |
477 | * Note: this has to be called from pmu::stop() callback, as the assumption | |
478 | * of the AUX buffer management code is that after pmu::stop(), the AUX | |
479 | * transaction must be stopped and therefore drop the AUX reference count. | |
fdc26706 | 480 | */ |
f4c0b0aa | 481 | void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size) |
fdc26706 | 482 | { |
ae0c2d99 | 483 | bool wakeup = !!(handle->aux_flags & PERF_AUX_FLAG_TRUNCATED); |
56de4e8f | 484 | struct perf_buffer *rb = handle->rb; |
2023a0d2 | 485 | unsigned long aux_head; |
fdc26706 | 486 | |
2023a0d2 AS |
487 | /* in overwrite mode, driver provides aux_head via handle */ |
488 | if (rb->aux_overwrite) { | |
f4c0b0aa | 489 | handle->aux_flags |= PERF_AUX_FLAG_OVERWRITE; |
2023a0d2 AS |
490 | |
491 | aux_head = handle->head; | |
2ab346cf | 492 | rb->aux_head = aux_head; |
2023a0d2 | 493 | } else { |
f4c0b0aa WD |
494 | handle->aux_flags &= ~PERF_AUX_FLAG_OVERWRITE; |
495 | ||
2ab346cf WD |
496 | aux_head = rb->aux_head; |
497 | rb->aux_head += size; | |
2023a0d2 | 498 | } |
fdc26706 | 499 | |
339bc418 AS |
500 | /* |
501 | * Only send RECORD_AUX if we have something useful to communicate | |
502 | * | |
503 | * Note: the OVERWRITE records by themselves are not considered | |
504 | * useful, as they don't communicate any *new* information, | |
505 | * aside from the short-lived offset, that becomes history at | |
506 | * the next event sched-in and therefore isn't useful. | |
507 | * The userspace that needs to copy out AUX data in overwrite | |
508 | * mode should know to use user_page::aux_head for the actual | |
509 | * offset. So, from now on we don't output AUX records that | |
510 | * have *only* OVERWRITE flag set. | |
511 | */ | |
512 | if (size || (handle->aux_flags & ~(u64)PERF_AUX_FLAG_OVERWRITE)) | |
513 | perf_event_aux_event(handle->event, aux_head, size, | |
514 | handle->aux_flags); | |
fdc26706 | 515 | |
4d839dd9 | 516 | WRITE_ONCE(rb->user_page->aux_head, rb->aux_head); |
441430eb | 517 | if (rb_need_aux_wakeup(rb)) |
3f56e687 | 518 | wakeup = true; |
3f56e687 AS |
519 | |
520 | if (wakeup) { | |
f4c0b0aa | 521 | if (handle->aux_flags & PERF_AUX_FLAG_TRUNCATED) |
1d54ad94 | 522 | handle->event->pending_disable = smp_processor_id(); |
3f56e687 AS |
523 | perf_output_wakeup(handle); |
524 | } | |
525 | ||
fdc26706 AS |
526 | handle->event = NULL; |
527 | ||
5322ea58 | 528 | WRITE_ONCE(rb->aux_nest, 0); |
af5bb4ed | 529 | /* can't be last */ |
fdc26706 | 530 | rb_free_aux(rb); |
95ff4ca2 | 531 | ring_buffer_put(rb); |
fdc26706 | 532 | } |
bc1d2020 | 533 | EXPORT_SYMBOL_GPL(perf_aux_output_end); |
fdc26706 AS |
534 | |
535 | /* | |
536 | * Skip over a given number of bytes in the AUX buffer, due to, for example, | |
537 | * hardware's alignment constraints. | |
538 | */ | |
539 | int perf_aux_output_skip(struct perf_output_handle *handle, unsigned long size) | |
540 | { | |
56de4e8f | 541 | struct perf_buffer *rb = handle->rb; |
fdc26706 AS |
542 | |
543 | if (size > handle->size) | |
544 | return -ENOSPC; | |
545 | ||
2ab346cf | 546 | rb->aux_head += size; |
fdc26706 | 547 | |
4d839dd9 | 548 | WRITE_ONCE(rb->user_page->aux_head, rb->aux_head); |
441430eb | 549 | if (rb_need_aux_wakeup(rb)) { |
1a594131 | 550 | perf_output_wakeup(handle); |
2ab346cf | 551 | handle->wakeup = rb->aux_wakeup + rb->aux_watermark; |
1a594131 AS |
552 | } |
553 | ||
2ab346cf | 554 | handle->head = rb->aux_head; |
fdc26706 AS |
555 | handle->size -= size; |
556 | ||
557 | return 0; | |
558 | } | |
bc1d2020 | 559 | EXPORT_SYMBOL_GPL(perf_aux_output_skip); |
fdc26706 AS |
560 | |
561 | void *perf_get_aux(struct perf_output_handle *handle) | |
562 | { | |
563 | /* this is only valid between perf_aux_output_begin and *_end */ | |
564 | if (!handle->event) | |
565 | return NULL; | |
566 | ||
567 | return handle->rb->aux_priv; | |
568 | } | |
bc1d2020 | 569 | EXPORT_SYMBOL_GPL(perf_get_aux); |
fdc26706 | 570 | |
a4faf00d AS |
571 | /* |
572 | * Copy out AUX data from an AUX handle. | |
573 | */ | |
574 | long perf_output_copy_aux(struct perf_output_handle *aux_handle, | |
575 | struct perf_output_handle *handle, | |
576 | unsigned long from, unsigned long to) | |
577 | { | |
56de4e8f | 578 | struct perf_buffer *rb = aux_handle->rb; |
a4faf00d | 579 | unsigned long tocopy, remainder, len = 0; |
a4faf00d AS |
580 | void *addr; |
581 | ||
582 | from &= (rb->aux_nr_pages << PAGE_SHIFT) - 1; | |
583 | to &= (rb->aux_nr_pages << PAGE_SHIFT) - 1; | |
584 | ||
585 | do { | |
586 | tocopy = PAGE_SIZE - offset_in_page(from); | |
587 | if (to > from) | |
588 | tocopy = min(tocopy, to - from); | |
589 | if (!tocopy) | |
590 | break; | |
591 | ||
592 | addr = rb->aux_pages[from >> PAGE_SHIFT]; | |
593 | addr += offset_in_page(from); | |
594 | ||
595 | remainder = perf_output_copy(handle, addr, tocopy); | |
596 | if (remainder) | |
597 | return -EFAULT; | |
598 | ||
599 | len += tocopy; | |
600 | from += tocopy; | |
601 | from &= (rb->aux_nr_pages << PAGE_SHIFT) - 1; | |
602 | } while (to != from); | |
603 | ||
604 | return len; | |
605 | } | |
606 | ||
0a4e38e6 AS |
607 | #define PERF_AUX_GFP (GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_NORETRY) |
608 | ||
609 | static struct page *rb_alloc_aux_page(int node, int order) | |
610 | { | |
611 | struct page *page; | |
612 | ||
5e0a760b KS |
613 | if (order > MAX_PAGE_ORDER) |
614 | order = MAX_PAGE_ORDER; | |
0a4e38e6 AS |
615 | |
616 | do { | |
617 | page = alloc_pages_node(node, PERF_AUX_GFP, order); | |
618 | } while (!page && order--); | |
619 | ||
620 | if (page && order) { | |
621 | /* | |
c2ad6b51 AS |
622 | * Communicate the allocation size to the driver: |
623 | * if we managed to secure a high-order allocation, | |
624 | * set its first page's private to this order; | |
625 | * !PagePrivate(page) means it's just a normal page. | |
0a4e38e6 AS |
626 | */ |
627 | split_page(page, order); | |
628 | SetPagePrivate(page); | |
629 | set_page_private(page, order); | |
630 | } | |
631 | ||
632 | return page; | |
633 | } | |
634 | ||
56de4e8f | 635 | static void rb_free_aux_page(struct perf_buffer *rb, int idx) |
0a4e38e6 AS |
636 | { |
637 | struct page *page = virt_to_page(rb->aux_pages[idx]); | |
638 | ||
639 | ClearPagePrivate(page); | |
640 | page->mapping = NULL; | |
641 | __free_page(page); | |
642 | } | |
643 | ||
56de4e8f | 644 | static void __rb_free_aux(struct perf_buffer *rb) |
45c815f0 AS |
645 | { |
646 | int pg; | |
647 | ||
95ff4ca2 AS |
648 | /* |
649 | * Should never happen, the last reference should be dropped from | |
650 | * perf_mmap_close() path, which first stops aux transactions (which | |
651 | * in turn are the atomic holders of aux_refcount) and then does the | |
652 | * last rb_free_aux(). | |
653 | */ | |
654 | WARN_ON_ONCE(in_atomic()); | |
655 | ||
45c815f0 AS |
656 | if (rb->aux_priv) { |
657 | rb->free_aux(rb->aux_priv); | |
658 | rb->free_aux = NULL; | |
659 | rb->aux_priv = NULL; | |
660 | } | |
661 | ||
662 | if (rb->aux_nr_pages) { | |
663 | for (pg = 0; pg < rb->aux_nr_pages; pg++) | |
664 | rb_free_aux_page(rb, pg); | |
665 | ||
666 | kfree(rb->aux_pages); | |
667 | rb->aux_nr_pages = 0; | |
668 | } | |
669 | } | |
670 | ||
56de4e8f | 671 | int rb_alloc_aux(struct perf_buffer *rb, struct perf_event *event, |
1a594131 | 672 | pgoff_t pgoff, int nr_pages, long watermark, int flags) |
45bfb2e5 PZ |
673 | { |
674 | bool overwrite = !(flags & RING_BUFFER_WRITABLE); | |
675 | int node = (event->cpu == -1) ? -1 : cpu_to_node(event->cpu); | |
5768402f | 676 | int ret = -ENOMEM, max_order; |
45bfb2e5 PZ |
677 | |
678 | if (!has_aux(event)) | |
8a1898db | 679 | return -EOPNOTSUPP; |
45bfb2e5 | 680 | |
26ae4f44 | 681 | if (!overwrite) { |
d68e6799 AS |
682 | /* |
683 | * Watermark defaults to half the buffer, and so does the | |
684 | * max_order, to aid PMU drivers in double buffering. | |
685 | */ | |
686 | if (!watermark) | |
687 | watermark = nr_pages << (PAGE_SHIFT - 1); | |
6a279230 | 688 | |
d68e6799 AS |
689 | /* |
690 | * Use aux_watermark as the basis for chunking to | |
691 | * help PMU drivers honor the watermark. | |
692 | */ | |
693 | max_order = get_order(watermark); | |
694 | } else { | |
695 | /* | |
696 | * We need to start with the max_order that fits in nr_pages, | |
697 | * not the other way around, hence ilog2() and not get_order. | |
698 | */ | |
699 | max_order = ilog2(nr_pages); | |
700 | watermark = 0; | |
6a279230 AS |
701 | } |
702 | ||
54aee5f1 SX |
703 | /* |
704 | * kcalloc_node() is unable to allocate buffer if the size is larger | |
5e0a760b | 705 | * than: PAGE_SIZE << MAX_PAGE_ORDER; directly bail out in this case. |
54aee5f1 | 706 | */ |
5e0a760b | 707 | if (get_order((unsigned long)nr_pages * sizeof(void *)) > MAX_PAGE_ORDER) |
54aee5f1 | 708 | return -ENOMEM; |
590b5b7d KC |
709 | rb->aux_pages = kcalloc_node(nr_pages, sizeof(void *), GFP_KERNEL, |
710 | node); | |
45bfb2e5 PZ |
711 | if (!rb->aux_pages) |
712 | return -ENOMEM; | |
713 | ||
714 | rb->free_aux = event->pmu->free_aux; | |
0a4e38e6 | 715 | for (rb->aux_nr_pages = 0; rb->aux_nr_pages < nr_pages;) { |
45bfb2e5 | 716 | struct page *page; |
0a4e38e6 | 717 | int last, order; |
45bfb2e5 | 718 | |
0a4e38e6 AS |
719 | order = min(max_order, ilog2(nr_pages - rb->aux_nr_pages)); |
720 | page = rb_alloc_aux_page(node, order); | |
45bfb2e5 PZ |
721 | if (!page) |
722 | goto out; | |
723 | ||
0a4e38e6 AS |
724 | for (last = rb->aux_nr_pages + (1 << page_private(page)); |
725 | last > rb->aux_nr_pages; rb->aux_nr_pages++) | |
726 | rb->aux_pages[rb->aux_nr_pages] = page_address(page++); | |
45bfb2e5 PZ |
727 | } |
728 | ||
aa319bcd AS |
729 | /* |
730 | * In overwrite mode, PMUs that don't support SG may not handle more | |
731 | * than one contiguous allocation, since they rely on PMI to do double | |
732 | * buffering. In this case, the entire buffer has to be one contiguous | |
733 | * chunk. | |
734 | */ | |
735 | if ((event->pmu->capabilities & PERF_PMU_CAP_AUX_NO_SG) && | |
736 | overwrite) { | |
737 | struct page *page = virt_to_page(rb->aux_pages[0]); | |
738 | ||
739 | if (page_private(page) != max_order) | |
740 | goto out; | |
741 | } | |
742 | ||
84001866 | 743 | rb->aux_priv = event->pmu->setup_aux(event, rb->aux_pages, nr_pages, |
45bfb2e5 PZ |
744 | overwrite); |
745 | if (!rb->aux_priv) | |
746 | goto out; | |
747 | ||
748 | ret = 0; | |
749 | ||
750 | /* | |
751 | * aux_pages (and pmu driver's private data, aux_priv) will be | |
752 | * referenced in both producer's and consumer's contexts, thus | |
753 | * we keep a refcount here to make sure either of the two can | |
754 | * reference them safely. | |
755 | */ | |
ca3bb3d0 | 756 | refcount_set(&rb->aux_refcount, 1); |
45bfb2e5 | 757 | |
2023a0d2 | 758 | rb->aux_overwrite = overwrite; |
1a594131 AS |
759 | rb->aux_watermark = watermark; |
760 | ||
45bfb2e5 PZ |
761 | out: |
762 | if (!ret) | |
763 | rb->aux_pgoff = pgoff; | |
764 | else | |
45c815f0 | 765 | __rb_free_aux(rb); |
45bfb2e5 PZ |
766 | |
767 | return ret; | |
768 | } | |
769 | ||
56de4e8f | 770 | void rb_free_aux(struct perf_buffer *rb) |
45bfb2e5 | 771 | { |
ca3bb3d0 | 772 | if (refcount_dec_and_test(&rb->aux_refcount)) |
45bfb2e5 PZ |
773 | __rb_free_aux(rb); |
774 | } | |
775 | ||
76369139 FW |
776 | #ifndef CONFIG_PERF_USE_VMALLOC |
777 | ||
778 | /* | |
779 | * Back perf_mmap() with regular GFP_KERNEL-0 pages. | |
780 | */ | |
781 | ||
45bfb2e5 | 782 | static struct page * |
56de4e8f | 783 | __perf_mmap_to_page(struct perf_buffer *rb, unsigned long pgoff) |
76369139 FW |
784 | { |
785 | if (pgoff > rb->nr_pages) | |
786 | return NULL; | |
787 | ||
788 | if (pgoff == 0) | |
789 | return virt_to_page(rb->user_page); | |
790 | ||
791 | return virt_to_page(rb->data_pages[pgoff - 1]); | |
792 | } | |
793 | ||
794 | static void *perf_mmap_alloc_page(int cpu) | |
795 | { | |
796 | struct page *page; | |
797 | int node; | |
798 | ||
799 | node = (cpu == -1) ? cpu : cpu_to_node(cpu); | |
800 | page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0); | |
801 | if (!page) | |
802 | return NULL; | |
803 | ||
804 | return page_address(page); | |
805 | } | |
806 | ||
d7e78706 YY |
807 | static void perf_mmap_free_page(void *addr) |
808 | { | |
809 | struct page *page = virt_to_page(addr); | |
810 | ||
811 | page->mapping = NULL; | |
812 | __free_page(page); | |
813 | } | |
814 | ||
56de4e8f | 815 | struct perf_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags) |
76369139 | 816 | { |
56de4e8f | 817 | struct perf_buffer *rb; |
76369139 | 818 | unsigned long size; |
9483409a | 819 | int i, node; |
76369139 | 820 | |
56de4e8f | 821 | size = sizeof(struct perf_buffer); |
76369139 FW |
822 | size += nr_pages * sizeof(void *); |
823 | ||
5e0a760b | 824 | if (order_base_2(size) > PAGE_SHIFT+MAX_PAGE_ORDER) |
9dff0aa9 MR |
825 | goto fail; |
826 | ||
9483409a NK |
827 | node = (cpu == -1) ? cpu : cpu_to_node(cpu); |
828 | rb = kzalloc_node(size, GFP_KERNEL, node); | |
76369139 FW |
829 | if (!rb) |
830 | goto fail; | |
831 | ||
832 | rb->user_page = perf_mmap_alloc_page(cpu); | |
833 | if (!rb->user_page) | |
834 | goto fail_user_page; | |
835 | ||
836 | for (i = 0; i < nr_pages; i++) { | |
837 | rb->data_pages[i] = perf_mmap_alloc_page(cpu); | |
838 | if (!rb->data_pages[i]) | |
839 | goto fail_data_pages; | |
840 | } | |
841 | ||
842 | rb->nr_pages = nr_pages; | |
843 | ||
844 | ring_buffer_init(rb, watermark, flags); | |
845 | ||
846 | return rb; | |
847 | ||
848 | fail_data_pages: | |
849 | for (i--; i >= 0; i--) | |
d7e78706 | 850 | perf_mmap_free_page(rb->data_pages[i]); |
76369139 | 851 | |
d7e78706 | 852 | perf_mmap_free_page(rb->user_page); |
76369139 FW |
853 | |
854 | fail_user_page: | |
855 | kfree(rb); | |
856 | ||
857 | fail: | |
858 | return NULL; | |
859 | } | |
860 | ||
56de4e8f | 861 | void rb_free(struct perf_buffer *rb) |
76369139 FW |
862 | { |
863 | int i; | |
864 | ||
8a9f91c5 | 865 | perf_mmap_free_page(rb->user_page); |
76369139 | 866 | for (i = 0; i < rb->nr_pages; i++) |
8a9f91c5 | 867 | perf_mmap_free_page(rb->data_pages[i]); |
76369139 FW |
868 | kfree(rb); |
869 | } | |
870 | ||
871 | #else | |
45bfb2e5 | 872 | static struct page * |
56de4e8f | 873 | __perf_mmap_to_page(struct perf_buffer *rb, unsigned long pgoff) |
76369139 | 874 | { |
5919b309 JO |
875 | /* The '>' counts in the user page. */ |
876 | if (pgoff > data_page_nr(rb)) | |
76369139 FW |
877 | return NULL; |
878 | ||
879 | return vmalloc_to_page((void *)rb->user_page + pgoff * PAGE_SIZE); | |
880 | } | |
881 | ||
882 | static void perf_mmap_unmark_page(void *addr) | |
883 | { | |
884 | struct page *page = vmalloc_to_page(addr); | |
885 | ||
886 | page->mapping = NULL; | |
887 | } | |
888 | ||
889 | static void rb_free_work(struct work_struct *work) | |
890 | { | |
56de4e8f | 891 | struct perf_buffer *rb; |
76369139 FW |
892 | void *base; |
893 | int i, nr; | |
894 | ||
56de4e8f | 895 | rb = container_of(work, struct perf_buffer, work); |
5919b309 | 896 | nr = data_page_nr(rb); |
76369139 FW |
897 | |
898 | base = rb->user_page; | |
5919b309 JO |
899 | /* The '<=' counts in the user page. */ |
900 | for (i = 0; i <= nr; i++) | |
76369139 FW |
901 | perf_mmap_unmark_page(base + (i * PAGE_SIZE)); |
902 | ||
903 | vfree(base); | |
904 | kfree(rb); | |
905 | } | |
906 | ||
56de4e8f | 907 | void rb_free(struct perf_buffer *rb) |
76369139 FW |
908 | { |
909 | schedule_work(&rb->work); | |
910 | } | |
911 | ||
56de4e8f | 912 | struct perf_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags) |
76369139 | 913 | { |
56de4e8f | 914 | struct perf_buffer *rb; |
76369139 FW |
915 | unsigned long size; |
916 | void *all_buf; | |
9483409a | 917 | int node; |
76369139 | 918 | |
56de4e8f | 919 | size = sizeof(struct perf_buffer); |
76369139 FW |
920 | size += sizeof(void *); |
921 | ||
9483409a NK |
922 | node = (cpu == -1) ? cpu : cpu_to_node(cpu); |
923 | rb = kzalloc_node(size, GFP_KERNEL, node); | |
76369139 FW |
924 | if (!rb) |
925 | goto fail; | |
926 | ||
927 | INIT_WORK(&rb->work, rb_free_work); | |
928 | ||
929 | all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE); | |
930 | if (!all_buf) | |
931 | goto fail_all_buf; | |
932 | ||
933 | rb->user_page = all_buf; | |
934 | rb->data_pages[0] = all_buf + PAGE_SIZE; | |
8184059e PZ |
935 | if (nr_pages) { |
936 | rb->nr_pages = 1; | |
937 | rb->page_order = ilog2(nr_pages); | |
938 | } | |
76369139 FW |
939 | |
940 | ring_buffer_init(rb, watermark, flags); | |
941 | ||
942 | return rb; | |
943 | ||
944 | fail_all_buf: | |
945 | kfree(rb); | |
946 | ||
947 | fail: | |
948 | return NULL; | |
949 | } | |
950 | ||
951 | #endif | |
45bfb2e5 PZ |
952 | |
953 | struct page * | |
56de4e8f | 954 | perf_mmap_to_page(struct perf_buffer *rb, unsigned long pgoff) |
45bfb2e5 PZ |
955 | { |
956 | if (rb->aux_nr_pages) { | |
957 | /* above AUX space */ | |
958 | if (pgoff > rb->aux_pgoff + rb->aux_nr_pages) | |
959 | return NULL; | |
960 | ||
961 | /* AUX space */ | |
4411ec1d PZ |
962 | if (pgoff >= rb->aux_pgoff) { |
963 | int aux_pgoff = array_index_nospec(pgoff - rb->aux_pgoff, rb->aux_nr_pages); | |
964 | return virt_to_page(rb->aux_pages[aux_pgoff]); | |
965 | } | |
45bfb2e5 PZ |
966 | } |
967 | ||
968 | return __perf_mmap_to_page(rb, pgoff); | |
969 | } |