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1// SPDX-License-Identifier: GPL-2.0-only
2/* binder_alloc.c
3 *
4 * Android IPC Subsystem
5 *
6 * Copyright (C) 2007-2017 Google, Inc.
7 */
8
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11#include <linux/list.h>
12#include <linux/sched/mm.h>
13#include <linux/module.h>
14#include <linux/rtmutex.h>
15#include <linux/rbtree.h>
16#include <linux/seq_file.h>
17#include <linux/vmalloc.h>
18#include <linux/slab.h>
19#include <linux/sched.h>
20#include <linux/list_lru.h>
21#include <linux/ratelimit.h>
22#include <asm/cacheflush.h>
23#include <linux/uaccess.h>
24#include <linux/highmem.h>
25#include <linux/sizes.h>
26#include "binder_alloc.h"
27#include "binder_trace.h"
28
29struct list_lru binder_freelist;
30
31static DEFINE_MUTEX(binder_alloc_mmap_lock);
32
33enum {
34 BINDER_DEBUG_USER_ERROR = 1U << 0,
35 BINDER_DEBUG_OPEN_CLOSE = 1U << 1,
36 BINDER_DEBUG_BUFFER_ALLOC = 1U << 2,
37 BINDER_DEBUG_BUFFER_ALLOC_ASYNC = 1U << 3,
38};
39static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
40
41module_param_named(debug_mask, binder_alloc_debug_mask,
42 uint, 0644);
43
44#define binder_alloc_debug(mask, x...) \
45 do { \
46 if (binder_alloc_debug_mask & mask) \
47 pr_info_ratelimited(x); \
48 } while (0)
49
50static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
51{
52 return list_entry(buffer->entry.next, struct binder_buffer, entry);
53}
54
55static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
56{
57 return list_entry(buffer->entry.prev, struct binder_buffer, entry);
58}
59
60static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
61 struct binder_buffer *buffer)
62{
63 if (list_is_last(&buffer->entry, &alloc->buffers))
64 return alloc->buffer + alloc->buffer_size - buffer->user_data;
65 return binder_buffer_next(buffer)->user_data - buffer->user_data;
66}
67
68static void binder_insert_free_buffer(struct binder_alloc *alloc,
69 struct binder_buffer *new_buffer)
70{
71 struct rb_node **p = &alloc->free_buffers.rb_node;
72 struct rb_node *parent = NULL;
73 struct binder_buffer *buffer;
74 size_t buffer_size;
75 size_t new_buffer_size;
76
77 BUG_ON(!new_buffer->free);
78
79 new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
80
81 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
82 "%d: add free buffer, size %zd, at %pK\n",
83 alloc->pid, new_buffer_size, new_buffer);
84
85 while (*p) {
86 parent = *p;
87 buffer = rb_entry(parent, struct binder_buffer, rb_node);
88 BUG_ON(!buffer->free);
89
90 buffer_size = binder_alloc_buffer_size(alloc, buffer);
91
92 if (new_buffer_size < buffer_size)
93 p = &parent->rb_left;
94 else
95 p = &parent->rb_right;
96 }
97 rb_link_node(&new_buffer->rb_node, parent, p);
98 rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
99}
100
101static void binder_insert_allocated_buffer_locked(
102 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
103{
104 struct rb_node **p = &alloc->allocated_buffers.rb_node;
105 struct rb_node *parent = NULL;
106 struct binder_buffer *buffer;
107
108 BUG_ON(new_buffer->free);
109
110 while (*p) {
111 parent = *p;
112 buffer = rb_entry(parent, struct binder_buffer, rb_node);
113 BUG_ON(buffer->free);
114
115 if (new_buffer->user_data < buffer->user_data)
116 p = &parent->rb_left;
117 else if (new_buffer->user_data > buffer->user_data)
118 p = &parent->rb_right;
119 else
120 BUG();
121 }
122 rb_link_node(&new_buffer->rb_node, parent, p);
123 rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
124}
125
126static struct binder_buffer *binder_alloc_prepare_to_free_locked(
127 struct binder_alloc *alloc,
128 unsigned long user_ptr)
129{
130 struct rb_node *n = alloc->allocated_buffers.rb_node;
131 struct binder_buffer *buffer;
132
133 while (n) {
134 buffer = rb_entry(n, struct binder_buffer, rb_node);
135 BUG_ON(buffer->free);
136
137 if (user_ptr < buffer->user_data) {
138 n = n->rb_left;
139 } else if (user_ptr > buffer->user_data) {
140 n = n->rb_right;
141 } else {
142 /*
143 * Guard against user threads attempting to
144 * free the buffer when in use by kernel or
145 * after it's already been freed.
146 */
147 if (!buffer->allow_user_free)
148 return ERR_PTR(-EPERM);
149 buffer->allow_user_free = 0;
150 return buffer;
151 }
152 }
153 return NULL;
154}
155
156/**
157 * binder_alloc_prepare_to_free() - get buffer given user ptr
158 * @alloc: binder_alloc for this proc
159 * @user_ptr: User pointer to buffer data
160 *
161 * Validate userspace pointer to buffer data and return buffer corresponding to
162 * that user pointer. Search the rb tree for buffer that matches user data
163 * pointer.
164 *
165 * Return: Pointer to buffer or NULL
166 */
167struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
168 unsigned long user_ptr)
169{
170 struct binder_buffer *buffer;
171
172 spin_lock(&alloc->lock);
173 buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
174 spin_unlock(&alloc->lock);
175 return buffer;
176}
177
178static inline void
179binder_set_installed_page(struct binder_lru_page *lru_page,
180 struct page *page)
181{
182 /* Pairs with acquire in binder_get_installed_page() */
183 smp_store_release(&lru_page->page_ptr, page);
184}
185
186static inline struct page *
187binder_get_installed_page(struct binder_lru_page *lru_page)
188{
189 /* Pairs with release in binder_set_installed_page() */
190 return smp_load_acquire(&lru_page->page_ptr);
191}
192
193static void binder_lru_freelist_add(struct binder_alloc *alloc,
194 unsigned long start, unsigned long end)
195{
196 struct binder_lru_page *page;
197 unsigned long page_addr;
198
199 trace_binder_update_page_range(alloc, false, start, end);
200
201 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
202 size_t index;
203 int ret;
204
205 index = (page_addr - alloc->buffer) / PAGE_SIZE;
206 page = &alloc->pages[index];
207
208 if (!binder_get_installed_page(page))
209 continue;
210
211 trace_binder_free_lru_start(alloc, index);
212
213 ret = list_lru_add_obj(&binder_freelist, &page->lru);
214 WARN_ON(!ret);
215
216 trace_binder_free_lru_end(alloc, index);
217 }
218}
219
220static int binder_install_single_page(struct binder_alloc *alloc,
221 struct binder_lru_page *lru_page,
222 unsigned long addr)
223{
224 struct page *page;
225 int ret = 0;
226
227 if (!mmget_not_zero(alloc->mm))
228 return -ESRCH;
229
230 /*
231 * Protected with mmap_sem in write mode as multiple tasks
232 * might race to install the same page.
233 */
234 mmap_write_lock(alloc->mm);
235 if (binder_get_installed_page(lru_page))
236 goto out;
237
238 if (!alloc->vma) {
239 pr_err("%d: %s failed, no vma\n", alloc->pid, __func__);
240 ret = -ESRCH;
241 goto out;
242 }
243
244 page = alloc_page(GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
245 if (!page) {
246 pr_err("%d: failed to allocate page\n", alloc->pid);
247 ret = -ENOMEM;
248 goto out;
249 }
250
251 ret = vm_insert_page(alloc->vma, addr, page);
252 if (ret) {
253 pr_err("%d: %s failed to insert page at offset %lx with %d\n",
254 alloc->pid, __func__, addr - alloc->buffer, ret);
255 __free_page(page);
256 ret = -ENOMEM;
257 goto out;
258 }
259
260 /* Mark page installation complete and safe to use */
261 binder_set_installed_page(lru_page, page);
262out:
263 mmap_write_unlock(alloc->mm);
264 mmput_async(alloc->mm);
265 return ret;
266}
267
268static int binder_install_buffer_pages(struct binder_alloc *alloc,
269 struct binder_buffer *buffer,
270 size_t size)
271{
272 struct binder_lru_page *page;
273 unsigned long start, final;
274 unsigned long page_addr;
275
276 start = buffer->user_data & PAGE_MASK;
277 final = PAGE_ALIGN(buffer->user_data + size);
278
279 for (page_addr = start; page_addr < final; page_addr += PAGE_SIZE) {
280 unsigned long index;
281 int ret;
282
283 index = (page_addr - alloc->buffer) / PAGE_SIZE;
284 page = &alloc->pages[index];
285
286 if (binder_get_installed_page(page))
287 continue;
288
289 trace_binder_alloc_page_start(alloc, index);
290
291 ret = binder_install_single_page(alloc, page, page_addr);
292 if (ret)
293 return ret;
294
295 trace_binder_alloc_page_end(alloc, index);
296 }
297
298 return 0;
299}
300
301/* The range of pages should exclude those shared with other buffers */
302static void binder_lru_freelist_del(struct binder_alloc *alloc,
303 unsigned long start, unsigned long end)
304{
305 struct binder_lru_page *page;
306 unsigned long page_addr;
307
308 trace_binder_update_page_range(alloc, true, start, end);
309
310 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
311 unsigned long index;
312 bool on_lru;
313
314 index = (page_addr - alloc->buffer) / PAGE_SIZE;
315 page = &alloc->pages[index];
316
317 if (page->page_ptr) {
318 trace_binder_alloc_lru_start(alloc, index);
319
320 on_lru = list_lru_del_obj(&binder_freelist, &page->lru);
321 WARN_ON(!on_lru);
322
323 trace_binder_alloc_lru_end(alloc, index);
324 continue;
325 }
326
327 if (index + 1 > alloc->pages_high)
328 alloc->pages_high = index + 1;
329 }
330}
331
332static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
333 struct vm_area_struct *vma)
334{
335 /* pairs with smp_load_acquire in binder_alloc_get_vma() */
336 smp_store_release(&alloc->vma, vma);
337}
338
339static inline struct vm_area_struct *binder_alloc_get_vma(
340 struct binder_alloc *alloc)
341{
342 /* pairs with smp_store_release in binder_alloc_set_vma() */
343 return smp_load_acquire(&alloc->vma);
344}
345
346static void debug_no_space_locked(struct binder_alloc *alloc)
347{
348 size_t largest_alloc_size = 0;
349 struct binder_buffer *buffer;
350 size_t allocated_buffers = 0;
351 size_t largest_free_size = 0;
352 size_t total_alloc_size = 0;
353 size_t total_free_size = 0;
354 size_t free_buffers = 0;
355 size_t buffer_size;
356 struct rb_node *n;
357
358 for (n = rb_first(&alloc->allocated_buffers); n; n = rb_next(n)) {
359 buffer = rb_entry(n, struct binder_buffer, rb_node);
360 buffer_size = binder_alloc_buffer_size(alloc, buffer);
361 allocated_buffers++;
362 total_alloc_size += buffer_size;
363 if (buffer_size > largest_alloc_size)
364 largest_alloc_size = buffer_size;
365 }
366
367 for (n = rb_first(&alloc->free_buffers); n; n = rb_next(n)) {
368 buffer = rb_entry(n, struct binder_buffer, rb_node);
369 buffer_size = binder_alloc_buffer_size(alloc, buffer);
370 free_buffers++;
371 total_free_size += buffer_size;
372 if (buffer_size > largest_free_size)
373 largest_free_size = buffer_size;
374 }
375
376 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
377 "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
378 total_alloc_size, allocated_buffers,
379 largest_alloc_size, total_free_size,
380 free_buffers, largest_free_size);
381}
382
383static bool debug_low_async_space_locked(struct binder_alloc *alloc)
384{
385 /*
386 * Find the amount and size of buffers allocated by the current caller;
387 * The idea is that once we cross the threshold, whoever is responsible
388 * for the low async space is likely to try to send another async txn,
389 * and at some point we'll catch them in the act. This is more efficient
390 * than keeping a map per pid.
391 */
392 struct binder_buffer *buffer;
393 size_t total_alloc_size = 0;
394 int pid = current->tgid;
395 size_t num_buffers = 0;
396 struct rb_node *n;
397
398 /*
399 * Only start detecting spammers once we have less than 20% of async
400 * space left (which is less than 10% of total buffer size).
401 */
402 if (alloc->free_async_space >= alloc->buffer_size / 10) {
403 alloc->oneway_spam_detected = false;
404 return false;
405 }
406
407 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
408 n = rb_next(n)) {
409 buffer = rb_entry(n, struct binder_buffer, rb_node);
410 if (buffer->pid != pid)
411 continue;
412 if (!buffer->async_transaction)
413 continue;
414 total_alloc_size += binder_alloc_buffer_size(alloc, buffer);
415 num_buffers++;
416 }
417
418 /*
419 * Warn if this pid has more than 50 transactions, or more than 50% of
420 * async space (which is 25% of total buffer size). Oneway spam is only
421 * detected when the threshold is exceeded.
422 */
423 if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) {
424 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
425 "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n",
426 alloc->pid, pid, num_buffers, total_alloc_size);
427 if (!alloc->oneway_spam_detected) {
428 alloc->oneway_spam_detected = true;
429 return true;
430 }
431 }
432 return false;
433}
434
435/* Callers preallocate @new_buffer, it is freed by this function if unused */
436static struct binder_buffer *binder_alloc_new_buf_locked(
437 struct binder_alloc *alloc,
438 struct binder_buffer *new_buffer,
439 size_t size,
440 int is_async)
441{
442 struct rb_node *n = alloc->free_buffers.rb_node;
443 struct rb_node *best_fit = NULL;
444 struct binder_buffer *buffer;
445 unsigned long next_used_page;
446 unsigned long curr_last_page;
447 size_t buffer_size;
448
449 if (is_async && alloc->free_async_space < size) {
450 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
451 "%d: binder_alloc_buf size %zd failed, no async space left\n",
452 alloc->pid, size);
453 buffer = ERR_PTR(-ENOSPC);
454 goto out;
455 }
456
457 while (n) {
458 buffer = rb_entry(n, struct binder_buffer, rb_node);
459 BUG_ON(!buffer->free);
460 buffer_size = binder_alloc_buffer_size(alloc, buffer);
461
462 if (size < buffer_size) {
463 best_fit = n;
464 n = n->rb_left;
465 } else if (size > buffer_size) {
466 n = n->rb_right;
467 } else {
468 best_fit = n;
469 break;
470 }
471 }
472
473 if (unlikely(!best_fit)) {
474 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
475 "%d: binder_alloc_buf size %zd failed, no address space\n",
476 alloc->pid, size);
477 debug_no_space_locked(alloc);
478 buffer = ERR_PTR(-ENOSPC);
479 goto out;
480 }
481
482 if (buffer_size != size) {
483 /* Found an oversized buffer and needs to be split */
484 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
485 buffer_size = binder_alloc_buffer_size(alloc, buffer);
486
487 WARN_ON(n || buffer_size == size);
488 new_buffer->user_data = buffer->user_data + size;
489 list_add(&new_buffer->entry, &buffer->entry);
490 new_buffer->free = 1;
491 binder_insert_free_buffer(alloc, new_buffer);
492 new_buffer = NULL;
493 }
494
495 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
496 "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
497 alloc->pid, size, buffer, buffer_size);
498
499 /*
500 * Now we remove the pages from the freelist. A clever calculation
501 * with buffer_size determines if the last page is shared with an
502 * adjacent in-use buffer. In such case, the page has been already
503 * removed from the freelist so we trim our range short.
504 */
505 next_used_page = (buffer->user_data + buffer_size) & PAGE_MASK;
506 curr_last_page = PAGE_ALIGN(buffer->user_data + size);
507 binder_lru_freelist_del(alloc, PAGE_ALIGN(buffer->user_data),
508 min(next_used_page, curr_last_page));
509
510 rb_erase(&buffer->rb_node, &alloc->free_buffers);
511 buffer->free = 0;
512 buffer->allow_user_free = 0;
513 binder_insert_allocated_buffer_locked(alloc, buffer);
514 buffer->async_transaction = is_async;
515 buffer->oneway_spam_suspect = false;
516 if (is_async) {
517 alloc->free_async_space -= size;
518 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
519 "%d: binder_alloc_buf size %zd async free %zd\n",
520 alloc->pid, size, alloc->free_async_space);
521 if (debug_low_async_space_locked(alloc))
522 buffer->oneway_spam_suspect = true;
523 }
524
525out:
526 /* Discard possibly unused new_buffer */
527 kfree(new_buffer);
528 return buffer;
529}
530
531/* Calculate the sanitized total size, returns 0 for invalid request */
532static inline size_t sanitized_size(size_t data_size,
533 size_t offsets_size,
534 size_t extra_buffers_size)
535{
536 size_t total, tmp;
537
538 /* Align to pointer size and check for overflows */
539 tmp = ALIGN(data_size, sizeof(void *)) +
540 ALIGN(offsets_size, sizeof(void *));
541 if (tmp < data_size || tmp < offsets_size)
542 return 0;
543 total = tmp + ALIGN(extra_buffers_size, sizeof(void *));
544 if (total < tmp || total < extra_buffers_size)
545 return 0;
546
547 /* Pad 0-sized buffers so they get a unique address */
548 total = max(total, sizeof(void *));
549
550 return total;
551}
552
553/**
554 * binder_alloc_new_buf() - Allocate a new binder buffer
555 * @alloc: binder_alloc for this proc
556 * @data_size: size of user data buffer
557 * @offsets_size: user specified buffer offset
558 * @extra_buffers_size: size of extra space for meta-data (eg, security context)
559 * @is_async: buffer for async transaction
560 *
561 * Allocate a new buffer given the requested sizes. Returns
562 * the kernel version of the buffer pointer. The size allocated
563 * is the sum of the three given sizes (each rounded up to
564 * pointer-sized boundary)
565 *
566 * Return: The allocated buffer or %ERR_PTR(-errno) if error
567 */
568struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
569 size_t data_size,
570 size_t offsets_size,
571 size_t extra_buffers_size,
572 int is_async)
573{
574 struct binder_buffer *buffer, *next;
575 size_t size;
576 int ret;
577
578 /* Check binder_alloc is fully initialized */
579 if (!binder_alloc_get_vma(alloc)) {
580 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
581 "%d: binder_alloc_buf, no vma\n",
582 alloc->pid);
583 return ERR_PTR(-ESRCH);
584 }
585
586 size = sanitized_size(data_size, offsets_size, extra_buffers_size);
587 if (unlikely(!size)) {
588 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
589 "%d: got transaction with invalid size %zd-%zd-%zd\n",
590 alloc->pid, data_size, offsets_size,
591 extra_buffers_size);
592 return ERR_PTR(-EINVAL);
593 }
594
595 /* Preallocate the next buffer */
596 next = kzalloc(sizeof(*next), GFP_KERNEL);
597 if (!next)
598 return ERR_PTR(-ENOMEM);
599
600 spin_lock(&alloc->lock);
601 buffer = binder_alloc_new_buf_locked(alloc, next, size, is_async);
602 if (IS_ERR(buffer)) {
603 spin_unlock(&alloc->lock);
604 goto out;
605 }
606
607 buffer->data_size = data_size;
608 buffer->offsets_size = offsets_size;
609 buffer->extra_buffers_size = extra_buffers_size;
610 buffer->pid = current->tgid;
611 spin_unlock(&alloc->lock);
612
613 ret = binder_install_buffer_pages(alloc, buffer, size);
614 if (ret) {
615 binder_alloc_free_buf(alloc, buffer);
616 buffer = ERR_PTR(ret);
617 }
618out:
619 return buffer;
620}
621
622static unsigned long buffer_start_page(struct binder_buffer *buffer)
623{
624 return buffer->user_data & PAGE_MASK;
625}
626
627static unsigned long prev_buffer_end_page(struct binder_buffer *buffer)
628{
629 return (buffer->user_data - 1) & PAGE_MASK;
630}
631
632static void binder_delete_free_buffer(struct binder_alloc *alloc,
633 struct binder_buffer *buffer)
634{
635 struct binder_buffer *prev, *next;
636
637 if (PAGE_ALIGNED(buffer->user_data))
638 goto skip_freelist;
639
640 BUG_ON(alloc->buffers.next == &buffer->entry);
641 prev = binder_buffer_prev(buffer);
642 BUG_ON(!prev->free);
643 if (prev_buffer_end_page(prev) == buffer_start_page(buffer))
644 goto skip_freelist;
645
646 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
647 next = binder_buffer_next(buffer);
648 if (buffer_start_page(next) == buffer_start_page(buffer))
649 goto skip_freelist;
650 }
651
652 binder_lru_freelist_add(alloc, buffer_start_page(buffer),
653 buffer_start_page(buffer) + PAGE_SIZE);
654skip_freelist:
655 list_del(&buffer->entry);
656 kfree(buffer);
657}
658
659static void binder_free_buf_locked(struct binder_alloc *alloc,
660 struct binder_buffer *buffer)
661{
662 size_t size, buffer_size;
663
664 buffer_size = binder_alloc_buffer_size(alloc, buffer);
665
666 size = ALIGN(buffer->data_size, sizeof(void *)) +
667 ALIGN(buffer->offsets_size, sizeof(void *)) +
668 ALIGN(buffer->extra_buffers_size, sizeof(void *));
669
670 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
671 "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
672 alloc->pid, buffer, size, buffer_size);
673
674 BUG_ON(buffer->free);
675 BUG_ON(size > buffer_size);
676 BUG_ON(buffer->transaction != NULL);
677 BUG_ON(buffer->user_data < alloc->buffer);
678 BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
679
680 if (buffer->async_transaction) {
681 alloc->free_async_space += buffer_size;
682 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
683 "%d: binder_free_buf size %zd async free %zd\n",
684 alloc->pid, size, alloc->free_async_space);
685 }
686
687 binder_lru_freelist_add(alloc, PAGE_ALIGN(buffer->user_data),
688 (buffer->user_data + buffer_size) & PAGE_MASK);
689
690 rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
691 buffer->free = 1;
692 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
693 struct binder_buffer *next = binder_buffer_next(buffer);
694
695 if (next->free) {
696 rb_erase(&next->rb_node, &alloc->free_buffers);
697 binder_delete_free_buffer(alloc, next);
698 }
699 }
700 if (alloc->buffers.next != &buffer->entry) {
701 struct binder_buffer *prev = binder_buffer_prev(buffer);
702
703 if (prev->free) {
704 binder_delete_free_buffer(alloc, buffer);
705 rb_erase(&prev->rb_node, &alloc->free_buffers);
706 buffer = prev;
707 }
708 }
709 binder_insert_free_buffer(alloc, buffer);
710}
711
712/**
713 * binder_alloc_get_page() - get kernel pointer for given buffer offset
714 * @alloc: binder_alloc for this proc
715 * @buffer: binder buffer to be accessed
716 * @buffer_offset: offset into @buffer data
717 * @pgoffp: address to copy final page offset to
718 *
719 * Lookup the struct page corresponding to the address
720 * at @buffer_offset into @buffer->user_data. If @pgoffp is not
721 * NULL, the byte-offset into the page is written there.
722 *
723 * The caller is responsible to ensure that the offset points
724 * to a valid address within the @buffer and that @buffer is
725 * not freeable by the user. Since it can't be freed, we are
726 * guaranteed that the corresponding elements of @alloc->pages[]
727 * cannot change.
728 *
729 * Return: struct page
730 */
731static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
732 struct binder_buffer *buffer,
733 binder_size_t buffer_offset,
734 pgoff_t *pgoffp)
735{
736 binder_size_t buffer_space_offset = buffer_offset +
737 (buffer->user_data - alloc->buffer);
738 pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
739 size_t index = buffer_space_offset >> PAGE_SHIFT;
740 struct binder_lru_page *lru_page;
741
742 lru_page = &alloc->pages[index];
743 *pgoffp = pgoff;
744 return lru_page->page_ptr;
745}
746
747/**
748 * binder_alloc_clear_buf() - zero out buffer
749 * @alloc: binder_alloc for this proc
750 * @buffer: binder buffer to be cleared
751 *
752 * memset the given buffer to 0
753 */
754static void binder_alloc_clear_buf(struct binder_alloc *alloc,
755 struct binder_buffer *buffer)
756{
757 size_t bytes = binder_alloc_buffer_size(alloc, buffer);
758 binder_size_t buffer_offset = 0;
759
760 while (bytes) {
761 unsigned long size;
762 struct page *page;
763 pgoff_t pgoff;
764
765 page = binder_alloc_get_page(alloc, buffer,
766 buffer_offset, &pgoff);
767 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
768 memset_page(page, pgoff, 0, size);
769 bytes -= size;
770 buffer_offset += size;
771 }
772}
773
774/**
775 * binder_alloc_free_buf() - free a binder buffer
776 * @alloc: binder_alloc for this proc
777 * @buffer: kernel pointer to buffer
778 *
779 * Free the buffer allocated via binder_alloc_new_buf()
780 */
781void binder_alloc_free_buf(struct binder_alloc *alloc,
782 struct binder_buffer *buffer)
783{
784 /*
785 * We could eliminate the call to binder_alloc_clear_buf()
786 * from binder_alloc_deferred_release() by moving this to
787 * binder_free_buf_locked(). However, that could
788 * increase contention for the alloc->lock if clear_on_free
789 * is used frequently for large buffers. This lock is not
790 * needed for correctness here.
791 */
792 if (buffer->clear_on_free) {
793 binder_alloc_clear_buf(alloc, buffer);
794 buffer->clear_on_free = false;
795 }
796 spin_lock(&alloc->lock);
797 binder_free_buf_locked(alloc, buffer);
798 spin_unlock(&alloc->lock);
799}
800
801/**
802 * binder_alloc_mmap_handler() - map virtual address space for proc
803 * @alloc: alloc structure for this proc
804 * @vma: vma passed to mmap()
805 *
806 * Called by binder_mmap() to initialize the space specified in
807 * vma for allocating binder buffers
808 *
809 * Return:
810 * 0 = success
811 * -EBUSY = address space already mapped
812 * -ENOMEM = failed to map memory to given address space
813 */
814int binder_alloc_mmap_handler(struct binder_alloc *alloc,
815 struct vm_area_struct *vma)
816{
817 struct binder_buffer *buffer;
818 const char *failure_string;
819 int ret, i;
820
821 if (unlikely(vma->vm_mm != alloc->mm)) {
822 ret = -EINVAL;
823 failure_string = "invalid vma->vm_mm";
824 goto err_invalid_mm;
825 }
826
827 mutex_lock(&binder_alloc_mmap_lock);
828 if (alloc->buffer_size) {
829 ret = -EBUSY;
830 failure_string = "already mapped";
831 goto err_already_mapped;
832 }
833 alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
834 SZ_4M);
835 mutex_unlock(&binder_alloc_mmap_lock);
836
837 alloc->buffer = vma->vm_start;
838
839 alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
840 sizeof(alloc->pages[0]),
841 GFP_KERNEL);
842 if (alloc->pages == NULL) {
843 ret = -ENOMEM;
844 failure_string = "alloc page array";
845 goto err_alloc_pages_failed;
846 }
847
848 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
849 alloc->pages[i].alloc = alloc;
850 INIT_LIST_HEAD(&alloc->pages[i].lru);
851 }
852
853 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
854 if (!buffer) {
855 ret = -ENOMEM;
856 failure_string = "alloc buffer struct";
857 goto err_alloc_buf_struct_failed;
858 }
859
860 buffer->user_data = alloc->buffer;
861 list_add(&buffer->entry, &alloc->buffers);
862 buffer->free = 1;
863 binder_insert_free_buffer(alloc, buffer);
864 alloc->free_async_space = alloc->buffer_size / 2;
865
866 /* Signal binder_alloc is fully initialized */
867 binder_alloc_set_vma(alloc, vma);
868
869 return 0;
870
871err_alloc_buf_struct_failed:
872 kfree(alloc->pages);
873 alloc->pages = NULL;
874err_alloc_pages_failed:
875 alloc->buffer = 0;
876 mutex_lock(&binder_alloc_mmap_lock);
877 alloc->buffer_size = 0;
878err_already_mapped:
879 mutex_unlock(&binder_alloc_mmap_lock);
880err_invalid_mm:
881 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
882 "%s: %d %lx-%lx %s failed %d\n", __func__,
883 alloc->pid, vma->vm_start, vma->vm_end,
884 failure_string, ret);
885 return ret;
886}
887
888
889void binder_alloc_deferred_release(struct binder_alloc *alloc)
890{
891 struct rb_node *n;
892 int buffers, page_count;
893 struct binder_buffer *buffer;
894
895 buffers = 0;
896 spin_lock(&alloc->lock);
897 BUG_ON(alloc->vma);
898
899 while ((n = rb_first(&alloc->allocated_buffers))) {
900 buffer = rb_entry(n, struct binder_buffer, rb_node);
901
902 /* Transaction should already have been freed */
903 BUG_ON(buffer->transaction);
904
905 if (buffer->clear_on_free) {
906 binder_alloc_clear_buf(alloc, buffer);
907 buffer->clear_on_free = false;
908 }
909 binder_free_buf_locked(alloc, buffer);
910 buffers++;
911 }
912
913 while (!list_empty(&alloc->buffers)) {
914 buffer = list_first_entry(&alloc->buffers,
915 struct binder_buffer, entry);
916 WARN_ON(!buffer->free);
917
918 list_del(&buffer->entry);
919 WARN_ON_ONCE(!list_empty(&alloc->buffers));
920 kfree(buffer);
921 }
922
923 page_count = 0;
924 if (alloc->pages) {
925 int i;
926
927 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
928 unsigned long page_addr;
929 bool on_lru;
930
931 if (!alloc->pages[i].page_ptr)
932 continue;
933
934 on_lru = list_lru_del_obj(&binder_freelist,
935 &alloc->pages[i].lru);
936 page_addr = alloc->buffer + i * PAGE_SIZE;
937 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
938 "%s: %d: page %d %s\n",
939 __func__, alloc->pid, i,
940 on_lru ? "on lru" : "active");
941 __free_page(alloc->pages[i].page_ptr);
942 page_count++;
943 }
944 kfree(alloc->pages);
945 }
946 spin_unlock(&alloc->lock);
947 if (alloc->mm)
948 mmdrop(alloc->mm);
949
950 binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
951 "%s: %d buffers %d, pages %d\n",
952 __func__, alloc->pid, buffers, page_count);
953}
954
955/**
956 * binder_alloc_print_allocated() - print buffer info
957 * @m: seq_file for output via seq_printf()
958 * @alloc: binder_alloc for this proc
959 *
960 * Prints information about every buffer associated with
961 * the binder_alloc state to the given seq_file
962 */
963void binder_alloc_print_allocated(struct seq_file *m,
964 struct binder_alloc *alloc)
965{
966 struct binder_buffer *buffer;
967 struct rb_node *n;
968
969 spin_lock(&alloc->lock);
970 for (n = rb_first(&alloc->allocated_buffers); n; n = rb_next(n)) {
971 buffer = rb_entry(n, struct binder_buffer, rb_node);
972 seq_printf(m, " buffer %d: %lx size %zd:%zd:%zd %s\n",
973 buffer->debug_id,
974 buffer->user_data - alloc->buffer,
975 buffer->data_size, buffer->offsets_size,
976 buffer->extra_buffers_size,
977 buffer->transaction ? "active" : "delivered");
978 }
979 spin_unlock(&alloc->lock);
980}
981
982/**
983 * binder_alloc_print_pages() - print page usage
984 * @m: seq_file for output via seq_printf()
985 * @alloc: binder_alloc for this proc
986 */
987void binder_alloc_print_pages(struct seq_file *m,
988 struct binder_alloc *alloc)
989{
990 struct binder_lru_page *page;
991 int i;
992 int active = 0;
993 int lru = 0;
994 int free = 0;
995
996 spin_lock(&alloc->lock);
997 /*
998 * Make sure the binder_alloc is fully initialized, otherwise we might
999 * read inconsistent state.
1000 */
1001 if (binder_alloc_get_vma(alloc) != NULL) {
1002 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
1003 page = &alloc->pages[i];
1004 if (!page->page_ptr)
1005 free++;
1006 else if (list_empty(&page->lru))
1007 active++;
1008 else
1009 lru++;
1010 }
1011 }
1012 spin_unlock(&alloc->lock);
1013 seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
1014 seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);
1015}
1016
1017/**
1018 * binder_alloc_get_allocated_count() - return count of buffers
1019 * @alloc: binder_alloc for this proc
1020 *
1021 * Return: count of allocated buffers
1022 */
1023int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
1024{
1025 struct rb_node *n;
1026 int count = 0;
1027
1028 spin_lock(&alloc->lock);
1029 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
1030 count++;
1031 spin_unlock(&alloc->lock);
1032 return count;
1033}
1034
1035
1036/**
1037 * binder_alloc_vma_close() - invalidate address space
1038 * @alloc: binder_alloc for this proc
1039 *
1040 * Called from binder_vma_close() when releasing address space.
1041 * Clears alloc->vma to prevent new incoming transactions from
1042 * allocating more buffers.
1043 */
1044void binder_alloc_vma_close(struct binder_alloc *alloc)
1045{
1046 binder_alloc_set_vma(alloc, NULL);
1047}
1048
1049/**
1050 * binder_alloc_free_page() - shrinker callback to free pages
1051 * @item: item to free
1052 * @lock: lock protecting the item
1053 * @cb_arg: callback argument
1054 *
1055 * Called from list_lru_walk() in binder_shrink_scan() to free
1056 * up pages when the system is under memory pressure.
1057 */
1058enum lru_status binder_alloc_free_page(struct list_head *item,
1059 struct list_lru_one *lru,
1060 spinlock_t *lock,
1061 void *cb_arg)
1062 __must_hold(lock)
1063{
1064 struct binder_lru_page *page = container_of(item, typeof(*page), lru);
1065 struct binder_alloc *alloc = page->alloc;
1066 struct mm_struct *mm = alloc->mm;
1067 struct vm_area_struct *vma;
1068 struct page *page_to_free;
1069 unsigned long page_addr;
1070 size_t index;
1071
1072 if (!mmget_not_zero(mm))
1073 goto err_mmget;
1074 if (!mmap_read_trylock(mm))
1075 goto err_mmap_read_lock_failed;
1076 if (!spin_trylock(&alloc->lock))
1077 goto err_get_alloc_lock_failed;
1078 if (!page->page_ptr)
1079 goto err_page_already_freed;
1080
1081 index = page - alloc->pages;
1082 page_addr = alloc->buffer + index * PAGE_SIZE;
1083
1084 vma = vma_lookup(mm, page_addr);
1085 if (vma && vma != binder_alloc_get_vma(alloc))
1086 goto err_invalid_vma;
1087
1088 trace_binder_unmap_kernel_start(alloc, index);
1089
1090 page_to_free = page->page_ptr;
1091 page->page_ptr = NULL;
1092
1093 trace_binder_unmap_kernel_end(alloc, index);
1094
1095 list_lru_isolate(lru, item);
1096 spin_unlock(&alloc->lock);
1097 spin_unlock(lock);
1098
1099 if (vma) {
1100 trace_binder_unmap_user_start(alloc, index);
1101
1102 zap_page_range_single(vma, page_addr, PAGE_SIZE, NULL);
1103
1104 trace_binder_unmap_user_end(alloc, index);
1105 }
1106
1107 mmap_read_unlock(mm);
1108 mmput_async(mm);
1109 __free_page(page_to_free);
1110
1111 spin_lock(lock);
1112 return LRU_REMOVED_RETRY;
1113
1114err_invalid_vma:
1115err_page_already_freed:
1116 spin_unlock(&alloc->lock);
1117err_get_alloc_lock_failed:
1118 mmap_read_unlock(mm);
1119err_mmap_read_lock_failed:
1120 mmput_async(mm);
1121err_mmget:
1122 return LRU_SKIP;
1123}
1124
1125static unsigned long
1126binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
1127{
1128 return list_lru_count(&binder_freelist);
1129}
1130
1131static unsigned long
1132binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1133{
1134 return list_lru_walk(&binder_freelist, binder_alloc_free_page,
1135 NULL, sc->nr_to_scan);
1136}
1137
1138static struct shrinker *binder_shrinker;
1139
1140/**
1141 * binder_alloc_init() - called by binder_open() for per-proc initialization
1142 * @alloc: binder_alloc for this proc
1143 *
1144 * Called from binder_open() to initialize binder_alloc fields for
1145 * new binder proc
1146 */
1147void binder_alloc_init(struct binder_alloc *alloc)
1148{
1149 alloc->pid = current->group_leader->pid;
1150 alloc->mm = current->mm;
1151 mmgrab(alloc->mm);
1152 spin_lock_init(&alloc->lock);
1153 INIT_LIST_HEAD(&alloc->buffers);
1154}
1155
1156int binder_alloc_shrinker_init(void)
1157{
1158 int ret;
1159
1160 ret = list_lru_init(&binder_freelist);
1161 if (ret)
1162 return ret;
1163
1164 binder_shrinker = shrinker_alloc(0, "android-binder");
1165 if (!binder_shrinker) {
1166 list_lru_destroy(&binder_freelist);
1167 return -ENOMEM;
1168 }
1169
1170 binder_shrinker->count_objects = binder_shrink_count;
1171 binder_shrinker->scan_objects = binder_shrink_scan;
1172
1173 shrinker_register(binder_shrinker);
1174
1175 return 0;
1176}
1177
1178void binder_alloc_shrinker_exit(void)
1179{
1180 shrinker_free(binder_shrinker);
1181 list_lru_destroy(&binder_freelist);
1182}
1183
1184/**
1185 * check_buffer() - verify that buffer/offset is safe to access
1186 * @alloc: binder_alloc for this proc
1187 * @buffer: binder buffer to be accessed
1188 * @offset: offset into @buffer data
1189 * @bytes: bytes to access from offset
1190 *
1191 * Check that the @offset/@bytes are within the size of the given
1192 * @buffer and that the buffer is currently active and not freeable.
1193 * Offsets must also be multiples of sizeof(u32). The kernel is
1194 * allowed to touch the buffer in two cases:
1195 *
1196 * 1) when the buffer is being created:
1197 * (buffer->free == 0 && buffer->allow_user_free == 0)
1198 * 2) when the buffer is being torn down:
1199 * (buffer->free == 0 && buffer->transaction == NULL).
1200 *
1201 * Return: true if the buffer is safe to access
1202 */
1203static inline bool check_buffer(struct binder_alloc *alloc,
1204 struct binder_buffer *buffer,
1205 binder_size_t offset, size_t bytes)
1206{
1207 size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1208
1209 return buffer_size >= bytes &&
1210 offset <= buffer_size - bytes &&
1211 IS_ALIGNED(offset, sizeof(u32)) &&
1212 !buffer->free &&
1213 (!buffer->allow_user_free || !buffer->transaction);
1214}
1215
1216/**
1217 * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1218 * @alloc: binder_alloc for this proc
1219 * @buffer: binder buffer to be accessed
1220 * @buffer_offset: offset into @buffer data
1221 * @from: userspace pointer to source buffer
1222 * @bytes: bytes to copy
1223 *
1224 * Copy bytes from source userspace to target buffer.
1225 *
1226 * Return: bytes remaining to be copied
1227 */
1228unsigned long
1229binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1230 struct binder_buffer *buffer,
1231 binder_size_t buffer_offset,
1232 const void __user *from,
1233 size_t bytes)
1234{
1235 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1236 return bytes;
1237
1238 while (bytes) {
1239 unsigned long size;
1240 unsigned long ret;
1241 struct page *page;
1242 pgoff_t pgoff;
1243 void *kptr;
1244
1245 page = binder_alloc_get_page(alloc, buffer,
1246 buffer_offset, &pgoff);
1247 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1248 kptr = kmap_local_page(page) + pgoff;
1249 ret = copy_from_user(kptr, from, size);
1250 kunmap_local(kptr);
1251 if (ret)
1252 return bytes - size + ret;
1253 bytes -= size;
1254 from += size;
1255 buffer_offset += size;
1256 }
1257 return 0;
1258}
1259
1260static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1261 bool to_buffer,
1262 struct binder_buffer *buffer,
1263 binder_size_t buffer_offset,
1264 void *ptr,
1265 size_t bytes)
1266{
1267 /* All copies must be 32-bit aligned and 32-bit size */
1268 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1269 return -EINVAL;
1270
1271 while (bytes) {
1272 unsigned long size;
1273 struct page *page;
1274 pgoff_t pgoff;
1275
1276 page = binder_alloc_get_page(alloc, buffer,
1277 buffer_offset, &pgoff);
1278 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1279 if (to_buffer)
1280 memcpy_to_page(page, pgoff, ptr, size);
1281 else
1282 memcpy_from_page(ptr, page, pgoff, size);
1283 bytes -= size;
1284 pgoff = 0;
1285 ptr = ptr + size;
1286 buffer_offset += size;
1287 }
1288 return 0;
1289}
1290
1291int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1292 struct binder_buffer *buffer,
1293 binder_size_t buffer_offset,
1294 void *src,
1295 size_t bytes)
1296{
1297 return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1298 src, bytes);
1299}
1300
1301int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1302 void *dest,
1303 struct binder_buffer *buffer,
1304 binder_size_t buffer_offset,
1305 size_t bytes)
1306{
1307 return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
1308 dest, bytes);
1309}
1// SPDX-License-Identifier: GPL-2.0-only
2/* binder_alloc.c
3 *
4 * Android IPC Subsystem
5 *
6 * Copyright (C) 2007-2017 Google, Inc.
7 */
8
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11#include <linux/list.h>
12#include <linux/sched/mm.h>
13#include <linux/module.h>
14#include <linux/rtmutex.h>
15#include <linux/rbtree.h>
16#include <linux/seq_file.h>
17#include <linux/vmalloc.h>
18#include <linux/slab.h>
19#include <linux/sched.h>
20#include <linux/list_lru.h>
21#include <linux/ratelimit.h>
22#include <asm/cacheflush.h>
23#include <linux/uaccess.h>
24#include <linux/highmem.h>
25#include <linux/sizes.h>
26#include "binder_alloc.h"
27#include "binder_trace.h"
28
29struct list_lru binder_alloc_lru;
30
31static DEFINE_MUTEX(binder_alloc_mmap_lock);
32
33enum {
34 BINDER_DEBUG_USER_ERROR = 1U << 0,
35 BINDER_DEBUG_OPEN_CLOSE = 1U << 1,
36 BINDER_DEBUG_BUFFER_ALLOC = 1U << 2,
37 BINDER_DEBUG_BUFFER_ALLOC_ASYNC = 1U << 3,
38};
39static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
40
41module_param_named(debug_mask, binder_alloc_debug_mask,
42 uint, 0644);
43
44#define binder_alloc_debug(mask, x...) \
45 do { \
46 if (binder_alloc_debug_mask & mask) \
47 pr_info_ratelimited(x); \
48 } while (0)
49
50static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
51{
52 return list_entry(buffer->entry.next, struct binder_buffer, entry);
53}
54
55static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
56{
57 return list_entry(buffer->entry.prev, struct binder_buffer, entry);
58}
59
60static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
61 struct binder_buffer *buffer)
62{
63 if (list_is_last(&buffer->entry, &alloc->buffers))
64 return alloc->buffer + alloc->buffer_size - buffer->user_data;
65 return binder_buffer_next(buffer)->user_data - buffer->user_data;
66}
67
68static void binder_insert_free_buffer(struct binder_alloc *alloc,
69 struct binder_buffer *new_buffer)
70{
71 struct rb_node **p = &alloc->free_buffers.rb_node;
72 struct rb_node *parent = NULL;
73 struct binder_buffer *buffer;
74 size_t buffer_size;
75 size_t new_buffer_size;
76
77 BUG_ON(!new_buffer->free);
78
79 new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
80
81 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
82 "%d: add free buffer, size %zd, at %pK\n",
83 alloc->pid, new_buffer_size, new_buffer);
84
85 while (*p) {
86 parent = *p;
87 buffer = rb_entry(parent, struct binder_buffer, rb_node);
88 BUG_ON(!buffer->free);
89
90 buffer_size = binder_alloc_buffer_size(alloc, buffer);
91
92 if (new_buffer_size < buffer_size)
93 p = &parent->rb_left;
94 else
95 p = &parent->rb_right;
96 }
97 rb_link_node(&new_buffer->rb_node, parent, p);
98 rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
99}
100
101static void binder_insert_allocated_buffer_locked(
102 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
103{
104 struct rb_node **p = &alloc->allocated_buffers.rb_node;
105 struct rb_node *parent = NULL;
106 struct binder_buffer *buffer;
107
108 BUG_ON(new_buffer->free);
109
110 while (*p) {
111 parent = *p;
112 buffer = rb_entry(parent, struct binder_buffer, rb_node);
113 BUG_ON(buffer->free);
114
115 if (new_buffer->user_data < buffer->user_data)
116 p = &parent->rb_left;
117 else if (new_buffer->user_data > buffer->user_data)
118 p = &parent->rb_right;
119 else
120 BUG();
121 }
122 rb_link_node(&new_buffer->rb_node, parent, p);
123 rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
124}
125
126static struct binder_buffer *binder_alloc_prepare_to_free_locked(
127 struct binder_alloc *alloc,
128 uintptr_t user_ptr)
129{
130 struct rb_node *n = alloc->allocated_buffers.rb_node;
131 struct binder_buffer *buffer;
132 void __user *uptr;
133
134 uptr = (void __user *)user_ptr;
135
136 while (n) {
137 buffer = rb_entry(n, struct binder_buffer, rb_node);
138 BUG_ON(buffer->free);
139
140 if (uptr < buffer->user_data)
141 n = n->rb_left;
142 else if (uptr > buffer->user_data)
143 n = n->rb_right;
144 else {
145 /*
146 * Guard against user threads attempting to
147 * free the buffer when in use by kernel or
148 * after it's already been freed.
149 */
150 if (!buffer->allow_user_free)
151 return ERR_PTR(-EPERM);
152 buffer->allow_user_free = 0;
153 return buffer;
154 }
155 }
156 return NULL;
157}
158
159/**
160 * binder_alloc_prepare_to_free() - get buffer given user ptr
161 * @alloc: binder_alloc for this proc
162 * @user_ptr: User pointer to buffer data
163 *
164 * Validate userspace pointer to buffer data and return buffer corresponding to
165 * that user pointer. Search the rb tree for buffer that matches user data
166 * pointer.
167 *
168 * Return: Pointer to buffer or NULL
169 */
170struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
171 uintptr_t user_ptr)
172{
173 struct binder_buffer *buffer;
174
175 mutex_lock(&alloc->mutex);
176 buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
177 mutex_unlock(&alloc->mutex);
178 return buffer;
179}
180
181static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
182 void __user *start, void __user *end)
183{
184 void __user *page_addr;
185 unsigned long user_page_addr;
186 struct binder_lru_page *page;
187 struct vm_area_struct *vma = NULL;
188 struct mm_struct *mm = NULL;
189 bool need_mm = false;
190
191 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
192 "%d: %s pages %pK-%pK\n", alloc->pid,
193 allocate ? "allocate" : "free", start, end);
194
195 if (end <= start)
196 return 0;
197
198 trace_binder_update_page_range(alloc, allocate, start, end);
199
200 if (allocate == 0)
201 goto free_range;
202
203 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
204 page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
205 if (!page->page_ptr) {
206 need_mm = true;
207 break;
208 }
209 }
210
211 if (need_mm && mmget_not_zero(alloc->vma_vm_mm))
212 mm = alloc->vma_vm_mm;
213
214 if (mm) {
215 mmap_read_lock(mm);
216 vma = alloc->vma;
217 }
218
219 if (!vma && need_mm) {
220 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
221 "%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
222 alloc->pid);
223 goto err_no_vma;
224 }
225
226 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
227 int ret;
228 bool on_lru;
229 size_t index;
230
231 index = (page_addr - alloc->buffer) / PAGE_SIZE;
232 page = &alloc->pages[index];
233
234 if (page->page_ptr) {
235 trace_binder_alloc_lru_start(alloc, index);
236
237 on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
238 WARN_ON(!on_lru);
239
240 trace_binder_alloc_lru_end(alloc, index);
241 continue;
242 }
243
244 if (WARN_ON(!vma))
245 goto err_page_ptr_cleared;
246
247 trace_binder_alloc_page_start(alloc, index);
248 page->page_ptr = alloc_page(GFP_KERNEL |
249 __GFP_HIGHMEM |
250 __GFP_ZERO);
251 if (!page->page_ptr) {
252 pr_err("%d: binder_alloc_buf failed for page at %pK\n",
253 alloc->pid, page_addr);
254 goto err_alloc_page_failed;
255 }
256 page->alloc = alloc;
257 INIT_LIST_HEAD(&page->lru);
258
259 user_page_addr = (uintptr_t)page_addr;
260 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
261 if (ret) {
262 pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
263 alloc->pid, user_page_addr);
264 goto err_vm_insert_page_failed;
265 }
266
267 if (index + 1 > alloc->pages_high)
268 alloc->pages_high = index + 1;
269
270 trace_binder_alloc_page_end(alloc, index);
271 }
272 if (mm) {
273 mmap_read_unlock(mm);
274 mmput(mm);
275 }
276 return 0;
277
278free_range:
279 for (page_addr = end - PAGE_SIZE; 1; page_addr -= PAGE_SIZE) {
280 bool ret;
281 size_t index;
282
283 index = (page_addr - alloc->buffer) / PAGE_SIZE;
284 page = &alloc->pages[index];
285
286 trace_binder_free_lru_start(alloc, index);
287
288 ret = list_lru_add(&binder_alloc_lru, &page->lru);
289 WARN_ON(!ret);
290
291 trace_binder_free_lru_end(alloc, index);
292 if (page_addr == start)
293 break;
294 continue;
295
296err_vm_insert_page_failed:
297 __free_page(page->page_ptr);
298 page->page_ptr = NULL;
299err_alloc_page_failed:
300err_page_ptr_cleared:
301 if (page_addr == start)
302 break;
303 }
304err_no_vma:
305 if (mm) {
306 mmap_read_unlock(mm);
307 mmput(mm);
308 }
309 return vma ? -ENOMEM : -ESRCH;
310}
311
312
313static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
314 struct vm_area_struct *vma)
315{
316 if (vma)
317 alloc->vma_vm_mm = vma->vm_mm;
318 /*
319 * If we see alloc->vma is not NULL, buffer data structures set up
320 * completely. Look at smp_rmb side binder_alloc_get_vma.
321 * We also want to guarantee new alloc->vma_vm_mm is always visible
322 * if alloc->vma is set.
323 */
324 smp_wmb();
325 alloc->vma = vma;
326}
327
328static inline struct vm_area_struct *binder_alloc_get_vma(
329 struct binder_alloc *alloc)
330{
331 struct vm_area_struct *vma = NULL;
332
333 if (alloc->vma) {
334 /* Look at description in binder_alloc_set_vma */
335 smp_rmb();
336 vma = alloc->vma;
337 }
338 return vma;
339}
340
341static bool debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
342{
343 /*
344 * Find the amount and size of buffers allocated by the current caller;
345 * The idea is that once we cross the threshold, whoever is responsible
346 * for the low async space is likely to try to send another async txn,
347 * and at some point we'll catch them in the act. This is more efficient
348 * than keeping a map per pid.
349 */
350 struct rb_node *n;
351 struct binder_buffer *buffer;
352 size_t total_alloc_size = 0;
353 size_t num_buffers = 0;
354
355 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
356 n = rb_next(n)) {
357 buffer = rb_entry(n, struct binder_buffer, rb_node);
358 if (buffer->pid != pid)
359 continue;
360 if (!buffer->async_transaction)
361 continue;
362 total_alloc_size += binder_alloc_buffer_size(alloc, buffer)
363 + sizeof(struct binder_buffer);
364 num_buffers++;
365 }
366
367 /*
368 * Warn if this pid has more than 50 transactions, or more than 50% of
369 * async space (which is 25% of total buffer size). Oneway spam is only
370 * detected when the threshold is exceeded.
371 */
372 if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) {
373 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
374 "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n",
375 alloc->pid, pid, num_buffers, total_alloc_size);
376 if (!alloc->oneway_spam_detected) {
377 alloc->oneway_spam_detected = true;
378 return true;
379 }
380 }
381 return false;
382}
383
384static struct binder_buffer *binder_alloc_new_buf_locked(
385 struct binder_alloc *alloc,
386 size_t data_size,
387 size_t offsets_size,
388 size_t extra_buffers_size,
389 int is_async,
390 int pid)
391{
392 struct rb_node *n = alloc->free_buffers.rb_node;
393 struct binder_buffer *buffer;
394 size_t buffer_size;
395 struct rb_node *best_fit = NULL;
396 void __user *has_page_addr;
397 void __user *end_page_addr;
398 size_t size, data_offsets_size;
399 int ret;
400
401 if (!binder_alloc_get_vma(alloc)) {
402 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
403 "%d: binder_alloc_buf, no vma\n",
404 alloc->pid);
405 return ERR_PTR(-ESRCH);
406 }
407
408 data_offsets_size = ALIGN(data_size, sizeof(void *)) +
409 ALIGN(offsets_size, sizeof(void *));
410
411 if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
412 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
413 "%d: got transaction with invalid size %zd-%zd\n",
414 alloc->pid, data_size, offsets_size);
415 return ERR_PTR(-EINVAL);
416 }
417 size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
418 if (size < data_offsets_size || size < extra_buffers_size) {
419 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
420 "%d: got transaction with invalid extra_buffers_size %zd\n",
421 alloc->pid, extra_buffers_size);
422 return ERR_PTR(-EINVAL);
423 }
424 if (is_async &&
425 alloc->free_async_space < size + sizeof(struct binder_buffer)) {
426 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
427 "%d: binder_alloc_buf size %zd failed, no async space left\n",
428 alloc->pid, size);
429 return ERR_PTR(-ENOSPC);
430 }
431
432 /* Pad 0-size buffers so they get assigned unique addresses */
433 size = max(size, sizeof(void *));
434
435 while (n) {
436 buffer = rb_entry(n, struct binder_buffer, rb_node);
437 BUG_ON(!buffer->free);
438 buffer_size = binder_alloc_buffer_size(alloc, buffer);
439
440 if (size < buffer_size) {
441 best_fit = n;
442 n = n->rb_left;
443 } else if (size > buffer_size)
444 n = n->rb_right;
445 else {
446 best_fit = n;
447 break;
448 }
449 }
450 if (best_fit == NULL) {
451 size_t allocated_buffers = 0;
452 size_t largest_alloc_size = 0;
453 size_t total_alloc_size = 0;
454 size_t free_buffers = 0;
455 size_t largest_free_size = 0;
456 size_t total_free_size = 0;
457
458 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
459 n = rb_next(n)) {
460 buffer = rb_entry(n, struct binder_buffer, rb_node);
461 buffer_size = binder_alloc_buffer_size(alloc, buffer);
462 allocated_buffers++;
463 total_alloc_size += buffer_size;
464 if (buffer_size > largest_alloc_size)
465 largest_alloc_size = buffer_size;
466 }
467 for (n = rb_first(&alloc->free_buffers); n != NULL;
468 n = rb_next(n)) {
469 buffer = rb_entry(n, struct binder_buffer, rb_node);
470 buffer_size = binder_alloc_buffer_size(alloc, buffer);
471 free_buffers++;
472 total_free_size += buffer_size;
473 if (buffer_size > largest_free_size)
474 largest_free_size = buffer_size;
475 }
476 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
477 "%d: binder_alloc_buf size %zd failed, no address space\n",
478 alloc->pid, size);
479 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
480 "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
481 total_alloc_size, allocated_buffers,
482 largest_alloc_size, total_free_size,
483 free_buffers, largest_free_size);
484 return ERR_PTR(-ENOSPC);
485 }
486 if (n == NULL) {
487 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
488 buffer_size = binder_alloc_buffer_size(alloc, buffer);
489 }
490
491 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
492 "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
493 alloc->pid, size, buffer, buffer_size);
494
495 has_page_addr = (void __user *)
496 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
497 WARN_ON(n && buffer_size != size);
498 end_page_addr =
499 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
500 if (end_page_addr > has_page_addr)
501 end_page_addr = has_page_addr;
502 ret = binder_update_page_range(alloc, 1, (void __user *)
503 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
504 if (ret)
505 return ERR_PTR(ret);
506
507 if (buffer_size != size) {
508 struct binder_buffer *new_buffer;
509
510 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
511 if (!new_buffer) {
512 pr_err("%s: %d failed to alloc new buffer struct\n",
513 __func__, alloc->pid);
514 goto err_alloc_buf_struct_failed;
515 }
516 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
517 list_add(&new_buffer->entry, &buffer->entry);
518 new_buffer->free = 1;
519 binder_insert_free_buffer(alloc, new_buffer);
520 }
521
522 rb_erase(best_fit, &alloc->free_buffers);
523 buffer->free = 0;
524 buffer->allow_user_free = 0;
525 binder_insert_allocated_buffer_locked(alloc, buffer);
526 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
527 "%d: binder_alloc_buf size %zd got %pK\n",
528 alloc->pid, size, buffer);
529 buffer->data_size = data_size;
530 buffer->offsets_size = offsets_size;
531 buffer->async_transaction = is_async;
532 buffer->extra_buffers_size = extra_buffers_size;
533 buffer->pid = pid;
534 buffer->oneway_spam_suspect = false;
535 if (is_async) {
536 alloc->free_async_space -= size + sizeof(struct binder_buffer);
537 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
538 "%d: binder_alloc_buf size %zd async free %zd\n",
539 alloc->pid, size, alloc->free_async_space);
540 if (alloc->free_async_space < alloc->buffer_size / 10) {
541 /*
542 * Start detecting spammers once we have less than 20%
543 * of async space left (which is less than 10% of total
544 * buffer size).
545 */
546 buffer->oneway_spam_suspect = debug_low_async_space_locked(alloc, pid);
547 } else {
548 alloc->oneway_spam_detected = false;
549 }
550 }
551 return buffer;
552
553err_alloc_buf_struct_failed:
554 binder_update_page_range(alloc, 0, (void __user *)
555 PAGE_ALIGN((uintptr_t)buffer->user_data),
556 end_page_addr);
557 return ERR_PTR(-ENOMEM);
558}
559
560/**
561 * binder_alloc_new_buf() - Allocate a new binder buffer
562 * @alloc: binder_alloc for this proc
563 * @data_size: size of user data buffer
564 * @offsets_size: user specified buffer offset
565 * @extra_buffers_size: size of extra space for meta-data (eg, security context)
566 * @is_async: buffer for async transaction
567 * @pid: pid to attribute allocation to (used for debugging)
568 *
569 * Allocate a new buffer given the requested sizes. Returns
570 * the kernel version of the buffer pointer. The size allocated
571 * is the sum of the three given sizes (each rounded up to
572 * pointer-sized boundary)
573 *
574 * Return: The allocated buffer or %NULL if error
575 */
576struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
577 size_t data_size,
578 size_t offsets_size,
579 size_t extra_buffers_size,
580 int is_async,
581 int pid)
582{
583 struct binder_buffer *buffer;
584
585 mutex_lock(&alloc->mutex);
586 buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
587 extra_buffers_size, is_async, pid);
588 mutex_unlock(&alloc->mutex);
589 return buffer;
590}
591
592static void __user *buffer_start_page(struct binder_buffer *buffer)
593{
594 return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
595}
596
597static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
598{
599 return (void __user *)
600 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
601}
602
603static void binder_delete_free_buffer(struct binder_alloc *alloc,
604 struct binder_buffer *buffer)
605{
606 struct binder_buffer *prev, *next = NULL;
607 bool to_free = true;
608
609 BUG_ON(alloc->buffers.next == &buffer->entry);
610 prev = binder_buffer_prev(buffer);
611 BUG_ON(!prev->free);
612 if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
613 to_free = false;
614 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
615 "%d: merge free, buffer %pK share page with %pK\n",
616 alloc->pid, buffer->user_data,
617 prev->user_data);
618 }
619
620 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
621 next = binder_buffer_next(buffer);
622 if (buffer_start_page(next) == buffer_start_page(buffer)) {
623 to_free = false;
624 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
625 "%d: merge free, buffer %pK share page with %pK\n",
626 alloc->pid,
627 buffer->user_data,
628 next->user_data);
629 }
630 }
631
632 if (PAGE_ALIGNED(buffer->user_data)) {
633 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
634 "%d: merge free, buffer start %pK is page aligned\n",
635 alloc->pid, buffer->user_data);
636 to_free = false;
637 }
638
639 if (to_free) {
640 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
641 "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
642 alloc->pid, buffer->user_data,
643 prev->user_data,
644 next ? next->user_data : NULL);
645 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
646 buffer_start_page(buffer) + PAGE_SIZE);
647 }
648 list_del(&buffer->entry);
649 kfree(buffer);
650}
651
652static void binder_free_buf_locked(struct binder_alloc *alloc,
653 struct binder_buffer *buffer)
654{
655 size_t size, buffer_size;
656
657 buffer_size = binder_alloc_buffer_size(alloc, buffer);
658
659 size = ALIGN(buffer->data_size, sizeof(void *)) +
660 ALIGN(buffer->offsets_size, sizeof(void *)) +
661 ALIGN(buffer->extra_buffers_size, sizeof(void *));
662
663 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
664 "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
665 alloc->pid, buffer, size, buffer_size);
666
667 BUG_ON(buffer->free);
668 BUG_ON(size > buffer_size);
669 BUG_ON(buffer->transaction != NULL);
670 BUG_ON(buffer->user_data < alloc->buffer);
671 BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
672
673 if (buffer->async_transaction) {
674 alloc->free_async_space += size + sizeof(struct binder_buffer);
675
676 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
677 "%d: binder_free_buf size %zd async free %zd\n",
678 alloc->pid, size, alloc->free_async_space);
679 }
680
681 binder_update_page_range(alloc, 0,
682 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
683 (void __user *)(((uintptr_t)
684 buffer->user_data + buffer_size) & PAGE_MASK));
685
686 rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
687 buffer->free = 1;
688 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
689 struct binder_buffer *next = binder_buffer_next(buffer);
690
691 if (next->free) {
692 rb_erase(&next->rb_node, &alloc->free_buffers);
693 binder_delete_free_buffer(alloc, next);
694 }
695 }
696 if (alloc->buffers.next != &buffer->entry) {
697 struct binder_buffer *prev = binder_buffer_prev(buffer);
698
699 if (prev->free) {
700 binder_delete_free_buffer(alloc, buffer);
701 rb_erase(&prev->rb_node, &alloc->free_buffers);
702 buffer = prev;
703 }
704 }
705 binder_insert_free_buffer(alloc, buffer);
706}
707
708static void binder_alloc_clear_buf(struct binder_alloc *alloc,
709 struct binder_buffer *buffer);
710/**
711 * binder_alloc_free_buf() - free a binder buffer
712 * @alloc: binder_alloc for this proc
713 * @buffer: kernel pointer to buffer
714 *
715 * Free the buffer allocated via binder_alloc_new_buf()
716 */
717void binder_alloc_free_buf(struct binder_alloc *alloc,
718 struct binder_buffer *buffer)
719{
720 /*
721 * We could eliminate the call to binder_alloc_clear_buf()
722 * from binder_alloc_deferred_release() by moving this to
723 * binder_alloc_free_buf_locked(). However, that could
724 * increase contention for the alloc mutex if clear_on_free
725 * is used frequently for large buffers. The mutex is not
726 * needed for correctness here.
727 */
728 if (buffer->clear_on_free) {
729 binder_alloc_clear_buf(alloc, buffer);
730 buffer->clear_on_free = false;
731 }
732 mutex_lock(&alloc->mutex);
733 binder_free_buf_locked(alloc, buffer);
734 mutex_unlock(&alloc->mutex);
735}
736
737/**
738 * binder_alloc_mmap_handler() - map virtual address space for proc
739 * @alloc: alloc structure for this proc
740 * @vma: vma passed to mmap()
741 *
742 * Called by binder_mmap() to initialize the space specified in
743 * vma for allocating binder buffers
744 *
745 * Return:
746 * 0 = success
747 * -EBUSY = address space already mapped
748 * -ENOMEM = failed to map memory to given address space
749 */
750int binder_alloc_mmap_handler(struct binder_alloc *alloc,
751 struct vm_area_struct *vma)
752{
753 int ret;
754 const char *failure_string;
755 struct binder_buffer *buffer;
756
757 mutex_lock(&binder_alloc_mmap_lock);
758 if (alloc->buffer_size) {
759 ret = -EBUSY;
760 failure_string = "already mapped";
761 goto err_already_mapped;
762 }
763 alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
764 SZ_4M);
765 mutex_unlock(&binder_alloc_mmap_lock);
766
767 alloc->buffer = (void __user *)vma->vm_start;
768
769 alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
770 sizeof(alloc->pages[0]),
771 GFP_KERNEL);
772 if (alloc->pages == NULL) {
773 ret = -ENOMEM;
774 failure_string = "alloc page array";
775 goto err_alloc_pages_failed;
776 }
777
778 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
779 if (!buffer) {
780 ret = -ENOMEM;
781 failure_string = "alloc buffer struct";
782 goto err_alloc_buf_struct_failed;
783 }
784
785 buffer->user_data = alloc->buffer;
786 list_add(&buffer->entry, &alloc->buffers);
787 buffer->free = 1;
788 binder_insert_free_buffer(alloc, buffer);
789 alloc->free_async_space = alloc->buffer_size / 2;
790 binder_alloc_set_vma(alloc, vma);
791 mmgrab(alloc->vma_vm_mm);
792
793 return 0;
794
795err_alloc_buf_struct_failed:
796 kfree(alloc->pages);
797 alloc->pages = NULL;
798err_alloc_pages_failed:
799 alloc->buffer = NULL;
800 mutex_lock(&binder_alloc_mmap_lock);
801 alloc->buffer_size = 0;
802err_already_mapped:
803 mutex_unlock(&binder_alloc_mmap_lock);
804 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
805 "%s: %d %lx-%lx %s failed %d\n", __func__,
806 alloc->pid, vma->vm_start, vma->vm_end,
807 failure_string, ret);
808 return ret;
809}
810
811
812void binder_alloc_deferred_release(struct binder_alloc *alloc)
813{
814 struct rb_node *n;
815 int buffers, page_count;
816 struct binder_buffer *buffer;
817
818 buffers = 0;
819 mutex_lock(&alloc->mutex);
820 BUG_ON(alloc->vma);
821
822 while ((n = rb_first(&alloc->allocated_buffers))) {
823 buffer = rb_entry(n, struct binder_buffer, rb_node);
824
825 /* Transaction should already have been freed */
826 BUG_ON(buffer->transaction);
827
828 if (buffer->clear_on_free) {
829 binder_alloc_clear_buf(alloc, buffer);
830 buffer->clear_on_free = false;
831 }
832 binder_free_buf_locked(alloc, buffer);
833 buffers++;
834 }
835
836 while (!list_empty(&alloc->buffers)) {
837 buffer = list_first_entry(&alloc->buffers,
838 struct binder_buffer, entry);
839 WARN_ON(!buffer->free);
840
841 list_del(&buffer->entry);
842 WARN_ON_ONCE(!list_empty(&alloc->buffers));
843 kfree(buffer);
844 }
845
846 page_count = 0;
847 if (alloc->pages) {
848 int i;
849
850 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
851 void __user *page_addr;
852 bool on_lru;
853
854 if (!alloc->pages[i].page_ptr)
855 continue;
856
857 on_lru = list_lru_del(&binder_alloc_lru,
858 &alloc->pages[i].lru);
859 page_addr = alloc->buffer + i * PAGE_SIZE;
860 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
861 "%s: %d: page %d at %pK %s\n",
862 __func__, alloc->pid, i, page_addr,
863 on_lru ? "on lru" : "active");
864 __free_page(alloc->pages[i].page_ptr);
865 page_count++;
866 }
867 kfree(alloc->pages);
868 }
869 mutex_unlock(&alloc->mutex);
870 if (alloc->vma_vm_mm)
871 mmdrop(alloc->vma_vm_mm);
872
873 binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
874 "%s: %d buffers %d, pages %d\n",
875 __func__, alloc->pid, buffers, page_count);
876}
877
878static void print_binder_buffer(struct seq_file *m, const char *prefix,
879 struct binder_buffer *buffer)
880{
881 seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
882 prefix, buffer->debug_id, buffer->user_data,
883 buffer->data_size, buffer->offsets_size,
884 buffer->extra_buffers_size,
885 buffer->transaction ? "active" : "delivered");
886}
887
888/**
889 * binder_alloc_print_allocated() - print buffer info
890 * @m: seq_file for output via seq_printf()
891 * @alloc: binder_alloc for this proc
892 *
893 * Prints information about every buffer associated with
894 * the binder_alloc state to the given seq_file
895 */
896void binder_alloc_print_allocated(struct seq_file *m,
897 struct binder_alloc *alloc)
898{
899 struct rb_node *n;
900
901 mutex_lock(&alloc->mutex);
902 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
903 print_binder_buffer(m, " buffer",
904 rb_entry(n, struct binder_buffer, rb_node));
905 mutex_unlock(&alloc->mutex);
906}
907
908/**
909 * binder_alloc_print_pages() - print page usage
910 * @m: seq_file for output via seq_printf()
911 * @alloc: binder_alloc for this proc
912 */
913void binder_alloc_print_pages(struct seq_file *m,
914 struct binder_alloc *alloc)
915{
916 struct binder_lru_page *page;
917 int i;
918 int active = 0;
919 int lru = 0;
920 int free = 0;
921
922 mutex_lock(&alloc->mutex);
923 /*
924 * Make sure the binder_alloc is fully initialized, otherwise we might
925 * read inconsistent state.
926 */
927 if (binder_alloc_get_vma(alloc) != NULL) {
928 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
929 page = &alloc->pages[i];
930 if (!page->page_ptr)
931 free++;
932 else if (list_empty(&page->lru))
933 active++;
934 else
935 lru++;
936 }
937 }
938 mutex_unlock(&alloc->mutex);
939 seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
940 seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);
941}
942
943/**
944 * binder_alloc_get_allocated_count() - return count of buffers
945 * @alloc: binder_alloc for this proc
946 *
947 * Return: count of allocated buffers
948 */
949int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
950{
951 struct rb_node *n;
952 int count = 0;
953
954 mutex_lock(&alloc->mutex);
955 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
956 count++;
957 mutex_unlock(&alloc->mutex);
958 return count;
959}
960
961
962/**
963 * binder_alloc_vma_close() - invalidate address space
964 * @alloc: binder_alloc for this proc
965 *
966 * Called from binder_vma_close() when releasing address space.
967 * Clears alloc->vma to prevent new incoming transactions from
968 * allocating more buffers.
969 */
970void binder_alloc_vma_close(struct binder_alloc *alloc)
971{
972 binder_alloc_set_vma(alloc, NULL);
973}
974
975/**
976 * binder_alloc_free_page() - shrinker callback to free pages
977 * @item: item to free
978 * @lock: lock protecting the item
979 * @cb_arg: callback argument
980 *
981 * Called from list_lru_walk() in binder_shrink_scan() to free
982 * up pages when the system is under memory pressure.
983 */
984enum lru_status binder_alloc_free_page(struct list_head *item,
985 struct list_lru_one *lru,
986 spinlock_t *lock,
987 void *cb_arg)
988 __must_hold(lock)
989{
990 struct mm_struct *mm = NULL;
991 struct binder_lru_page *page = container_of(item,
992 struct binder_lru_page,
993 lru);
994 struct binder_alloc *alloc;
995 uintptr_t page_addr;
996 size_t index;
997 struct vm_area_struct *vma;
998
999 alloc = page->alloc;
1000 if (!mutex_trylock(&alloc->mutex))
1001 goto err_get_alloc_mutex_failed;
1002
1003 if (!page->page_ptr)
1004 goto err_page_already_freed;
1005
1006 index = page - alloc->pages;
1007 page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
1008
1009 mm = alloc->vma_vm_mm;
1010 if (!mmget_not_zero(mm))
1011 goto err_mmget;
1012 if (!mmap_read_trylock(mm))
1013 goto err_mmap_read_lock_failed;
1014 vma = binder_alloc_get_vma(alloc);
1015
1016 list_lru_isolate(lru, item);
1017 spin_unlock(lock);
1018
1019 if (vma) {
1020 trace_binder_unmap_user_start(alloc, index);
1021
1022 zap_page_range(vma, page_addr, PAGE_SIZE);
1023
1024 trace_binder_unmap_user_end(alloc, index);
1025 }
1026 mmap_read_unlock(mm);
1027 mmput_async(mm);
1028
1029 trace_binder_unmap_kernel_start(alloc, index);
1030
1031 __free_page(page->page_ptr);
1032 page->page_ptr = NULL;
1033
1034 trace_binder_unmap_kernel_end(alloc, index);
1035
1036 spin_lock(lock);
1037 mutex_unlock(&alloc->mutex);
1038 return LRU_REMOVED_RETRY;
1039
1040err_mmap_read_lock_failed:
1041 mmput_async(mm);
1042err_mmget:
1043err_page_already_freed:
1044 mutex_unlock(&alloc->mutex);
1045err_get_alloc_mutex_failed:
1046 return LRU_SKIP;
1047}
1048
1049static unsigned long
1050binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
1051{
1052 unsigned long ret = list_lru_count(&binder_alloc_lru);
1053 return ret;
1054}
1055
1056static unsigned long
1057binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1058{
1059 unsigned long ret;
1060
1061 ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
1062 NULL, sc->nr_to_scan);
1063 return ret;
1064}
1065
1066static struct shrinker binder_shrinker = {
1067 .count_objects = binder_shrink_count,
1068 .scan_objects = binder_shrink_scan,
1069 .seeks = DEFAULT_SEEKS,
1070};
1071
1072/**
1073 * binder_alloc_init() - called by binder_open() for per-proc initialization
1074 * @alloc: binder_alloc for this proc
1075 *
1076 * Called from binder_open() to initialize binder_alloc fields for
1077 * new binder proc
1078 */
1079void binder_alloc_init(struct binder_alloc *alloc)
1080{
1081 alloc->pid = current->group_leader->pid;
1082 mutex_init(&alloc->mutex);
1083 INIT_LIST_HEAD(&alloc->buffers);
1084}
1085
1086int binder_alloc_shrinker_init(void)
1087{
1088 int ret = list_lru_init(&binder_alloc_lru);
1089
1090 if (ret == 0) {
1091 ret = register_shrinker(&binder_shrinker);
1092 if (ret)
1093 list_lru_destroy(&binder_alloc_lru);
1094 }
1095 return ret;
1096}
1097
1098/**
1099 * check_buffer() - verify that buffer/offset is safe to access
1100 * @alloc: binder_alloc for this proc
1101 * @buffer: binder buffer to be accessed
1102 * @offset: offset into @buffer data
1103 * @bytes: bytes to access from offset
1104 *
1105 * Check that the @offset/@bytes are within the size of the given
1106 * @buffer and that the buffer is currently active and not freeable.
1107 * Offsets must also be multiples of sizeof(u32). The kernel is
1108 * allowed to touch the buffer in two cases:
1109 *
1110 * 1) when the buffer is being created:
1111 * (buffer->free == 0 && buffer->allow_user_free == 0)
1112 * 2) when the buffer is being torn down:
1113 * (buffer->free == 0 && buffer->transaction == NULL).
1114 *
1115 * Return: true if the buffer is safe to access
1116 */
1117static inline bool check_buffer(struct binder_alloc *alloc,
1118 struct binder_buffer *buffer,
1119 binder_size_t offset, size_t bytes)
1120{
1121 size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1122
1123 return buffer_size >= bytes &&
1124 offset <= buffer_size - bytes &&
1125 IS_ALIGNED(offset, sizeof(u32)) &&
1126 !buffer->free &&
1127 (!buffer->allow_user_free || !buffer->transaction);
1128}
1129
1130/**
1131 * binder_alloc_get_page() - get kernel pointer for given buffer offset
1132 * @alloc: binder_alloc for this proc
1133 * @buffer: binder buffer to be accessed
1134 * @buffer_offset: offset into @buffer data
1135 * @pgoffp: address to copy final page offset to
1136 *
1137 * Lookup the struct page corresponding to the address
1138 * at @buffer_offset into @buffer->user_data. If @pgoffp is not
1139 * NULL, the byte-offset into the page is written there.
1140 *
1141 * The caller is responsible to ensure that the offset points
1142 * to a valid address within the @buffer and that @buffer is
1143 * not freeable by the user. Since it can't be freed, we are
1144 * guaranteed that the corresponding elements of @alloc->pages[]
1145 * cannot change.
1146 *
1147 * Return: struct page
1148 */
1149static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1150 struct binder_buffer *buffer,
1151 binder_size_t buffer_offset,
1152 pgoff_t *pgoffp)
1153{
1154 binder_size_t buffer_space_offset = buffer_offset +
1155 (buffer->user_data - alloc->buffer);
1156 pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
1157 size_t index = buffer_space_offset >> PAGE_SHIFT;
1158 struct binder_lru_page *lru_page;
1159
1160 lru_page = &alloc->pages[index];
1161 *pgoffp = pgoff;
1162 return lru_page->page_ptr;
1163}
1164
1165/**
1166 * binder_alloc_clear_buf() - zero out buffer
1167 * @alloc: binder_alloc for this proc
1168 * @buffer: binder buffer to be cleared
1169 *
1170 * memset the given buffer to 0
1171 */
1172static void binder_alloc_clear_buf(struct binder_alloc *alloc,
1173 struct binder_buffer *buffer)
1174{
1175 size_t bytes = binder_alloc_buffer_size(alloc, buffer);
1176 binder_size_t buffer_offset = 0;
1177
1178 while (bytes) {
1179 unsigned long size;
1180 struct page *page;
1181 pgoff_t pgoff;
1182 void *kptr;
1183
1184 page = binder_alloc_get_page(alloc, buffer,
1185 buffer_offset, &pgoff);
1186 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1187 kptr = kmap(page) + pgoff;
1188 memset(kptr, 0, size);
1189 kunmap(page);
1190 bytes -= size;
1191 buffer_offset += size;
1192 }
1193}
1194
1195/**
1196 * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1197 * @alloc: binder_alloc for this proc
1198 * @buffer: binder buffer to be accessed
1199 * @buffer_offset: offset into @buffer data
1200 * @from: userspace pointer to source buffer
1201 * @bytes: bytes to copy
1202 *
1203 * Copy bytes from source userspace to target buffer.
1204 *
1205 * Return: bytes remaining to be copied
1206 */
1207unsigned long
1208binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1209 struct binder_buffer *buffer,
1210 binder_size_t buffer_offset,
1211 const void __user *from,
1212 size_t bytes)
1213{
1214 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1215 return bytes;
1216
1217 while (bytes) {
1218 unsigned long size;
1219 unsigned long ret;
1220 struct page *page;
1221 pgoff_t pgoff;
1222 void *kptr;
1223
1224 page = binder_alloc_get_page(alloc, buffer,
1225 buffer_offset, &pgoff);
1226 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1227 kptr = kmap(page) + pgoff;
1228 ret = copy_from_user(kptr, from, size);
1229 kunmap(page);
1230 if (ret)
1231 return bytes - size + ret;
1232 bytes -= size;
1233 from += size;
1234 buffer_offset += size;
1235 }
1236 return 0;
1237}
1238
1239static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1240 bool to_buffer,
1241 struct binder_buffer *buffer,
1242 binder_size_t buffer_offset,
1243 void *ptr,
1244 size_t bytes)
1245{
1246 /* All copies must be 32-bit aligned and 32-bit size */
1247 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1248 return -EINVAL;
1249
1250 while (bytes) {
1251 unsigned long size;
1252 struct page *page;
1253 pgoff_t pgoff;
1254 void *tmpptr;
1255 void *base_ptr;
1256
1257 page = binder_alloc_get_page(alloc, buffer,
1258 buffer_offset, &pgoff);
1259 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1260 base_ptr = kmap_atomic(page);
1261 tmpptr = base_ptr + pgoff;
1262 if (to_buffer)
1263 memcpy(tmpptr, ptr, size);
1264 else
1265 memcpy(ptr, tmpptr, size);
1266 /*
1267 * kunmap_atomic() takes care of flushing the cache
1268 * if this device has VIVT cache arch
1269 */
1270 kunmap_atomic(base_ptr);
1271 bytes -= size;
1272 pgoff = 0;
1273 ptr = ptr + size;
1274 buffer_offset += size;
1275 }
1276 return 0;
1277}
1278
1279int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1280 struct binder_buffer *buffer,
1281 binder_size_t buffer_offset,
1282 void *src,
1283 size_t bytes)
1284{
1285 return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1286 src, bytes);
1287}
1288
1289int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1290 void *dest,
1291 struct binder_buffer *buffer,
1292 binder_size_t buffer_offset,
1293 size_t bytes)
1294{
1295 return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
1296 dest, bytes);
1297}
1298