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