1 // SPDX-License-Identifier: GPL-2.0-only
4 * Android IPC Subsystem
6 * Copyright (C) 2007-2017 Google, Inc.
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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"
29 struct list_lru binder_alloc_lru;
31 static DEFINE_MUTEX(binder_alloc_mmap_lock);
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,
39 static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
41 module_param_named(debug_mask, binder_alloc_debug_mask,
44 #define binder_alloc_debug(mask, x...) \
46 if (binder_alloc_debug_mask & mask) \
47 pr_info_ratelimited(x); \
50 static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
52 return list_entry(buffer->entry.next, struct binder_buffer, entry);
55 static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
57 return list_entry(buffer->entry.prev, struct binder_buffer, entry);
60 static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
61 struct binder_buffer *buffer)
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;
68 static void binder_insert_free_buffer(struct binder_alloc *alloc,
69 struct binder_buffer *new_buffer)
71 struct rb_node **p = &alloc->free_buffers.rb_node;
72 struct rb_node *parent = NULL;
73 struct binder_buffer *buffer;
75 size_t new_buffer_size;
77 BUG_ON(!new_buffer->free);
79 new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
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);
87 buffer = rb_entry(parent, struct binder_buffer, rb_node);
88 BUG_ON(!buffer->free);
90 buffer_size = binder_alloc_buffer_size(alloc, buffer);
92 if (new_buffer_size < buffer_size)
95 p = &parent->rb_right;
97 rb_link_node(&new_buffer->rb_node, parent, p);
98 rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
101 static void binder_insert_allocated_buffer_locked(
102 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
104 struct rb_node **p = &alloc->allocated_buffers.rb_node;
105 struct rb_node *parent = NULL;
106 struct binder_buffer *buffer;
108 BUG_ON(new_buffer->free);
112 buffer = rb_entry(parent, struct binder_buffer, rb_node);
113 BUG_ON(buffer->free);
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;
122 rb_link_node(&new_buffer->rb_node, parent, p);
123 rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
126 static struct binder_buffer *binder_alloc_prepare_to_free_locked(
127 struct binder_alloc *alloc,
130 struct rb_node *n = alloc->allocated_buffers.rb_node;
131 struct binder_buffer *buffer;
134 uptr = (void __user *)user_ptr;
137 buffer = rb_entry(n, struct binder_buffer, rb_node);
138 BUG_ON(buffer->free);
140 if (uptr < buffer->user_data)
142 else if (uptr > buffer->user_data)
146 * Guard against user threads attempting to
147 * free the buffer when in use by kernel or
148 * after it's already been freed.
150 if (!buffer->allow_user_free)
151 return ERR_PTR(-EPERM);
152 buffer->allow_user_free = 0;
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
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
168 * Return: Pointer to buffer or NULL
170 struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
173 struct binder_buffer *buffer;
175 mutex_lock(&alloc->mutex);
176 buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
177 mutex_unlock(&alloc->mutex);
181 static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
182 void __user *start, void __user *end)
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;
191 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
192 "%d: %s pages %pK-%pK\n", alloc->pid,
193 allocate ? "allocate" : "free", start, end);
198 trace_binder_update_page_range(alloc, allocate, start, end);
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) {
211 if (need_mm && mmget_not_zero(alloc->mm))
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",
226 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
231 index = (page_addr - alloc->buffer) / PAGE_SIZE;
232 page = &alloc->pages[index];
234 if (page->page_ptr) {
235 trace_binder_alloc_lru_start(alloc, index);
237 on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
240 trace_binder_alloc_lru_end(alloc, index);
245 goto err_page_ptr_cleared;
247 trace_binder_alloc_page_start(alloc, index);
248 page->page_ptr = alloc_page(GFP_KERNEL |
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;
257 INIT_LIST_HEAD(&page->lru);
259 user_page_addr = (uintptr_t)page_addr;
260 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
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;
267 if (index + 1 > alloc->pages_high)
268 alloc->pages_high = index + 1;
270 trace_binder_alloc_page_end(alloc, index);
273 mmap_write_unlock(mm);
279 for (page_addr = end - PAGE_SIZE; 1; page_addr -= PAGE_SIZE) {
283 index = (page_addr - alloc->buffer) / PAGE_SIZE;
284 page = &alloc->pages[index];
286 trace_binder_free_lru_start(alloc, index);
288 ret = list_lru_add(&binder_alloc_lru, &page->lru);
291 trace_binder_free_lru_end(alloc, index);
292 if (page_addr == start)
296 err_vm_insert_page_failed:
297 __free_page(page->page_ptr);
298 page->page_ptr = NULL;
299 err_alloc_page_failed:
300 err_page_ptr_cleared:
301 if (page_addr == start)
306 mmap_write_unlock(mm);
309 return vma ? -ENOMEM : -ESRCH;
312 static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
313 struct vm_area_struct *vma)
315 /* pairs with smp_load_acquire in binder_alloc_get_vma() */
316 smp_store_release(&alloc->vma, vma);
319 static inline struct vm_area_struct *binder_alloc_get_vma(
320 struct binder_alloc *alloc)
322 /* pairs with smp_store_release in binder_alloc_set_vma() */
323 return smp_load_acquire(&alloc->vma);
326 static bool debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
329 * Find the amount and size of buffers allocated by the current caller;
330 * The idea is that once we cross the threshold, whoever is responsible
331 * for the low async space is likely to try to send another async txn,
332 * and at some point we'll catch them in the act. This is more efficient
333 * than keeping a map per pid.
336 struct binder_buffer *buffer;
337 size_t total_alloc_size = 0;
338 size_t num_buffers = 0;
340 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
342 buffer = rb_entry(n, struct binder_buffer, rb_node);
343 if (buffer->pid != pid)
345 if (!buffer->async_transaction)
347 total_alloc_size += binder_alloc_buffer_size(alloc, buffer)
348 + sizeof(struct binder_buffer);
353 * Warn if this pid has more than 50 transactions, or more than 50% of
354 * async space (which is 25% of total buffer size). Oneway spam is only
355 * detected when the threshold is exceeded.
357 if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) {
358 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
359 "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n",
360 alloc->pid, pid, num_buffers, total_alloc_size);
361 if (!alloc->oneway_spam_detected) {
362 alloc->oneway_spam_detected = true;
369 static struct binder_buffer *binder_alloc_new_buf_locked(
370 struct binder_alloc *alloc,
373 size_t extra_buffers_size,
377 struct rb_node *n = alloc->free_buffers.rb_node;
378 struct binder_buffer *buffer;
380 struct rb_node *best_fit = NULL;
381 void __user *has_page_addr;
382 void __user *end_page_addr;
383 size_t size, data_offsets_size;
386 /* Check binder_alloc is fully initialized */
387 if (!binder_alloc_get_vma(alloc)) {
388 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
389 "%d: binder_alloc_buf, no vma\n",
391 return ERR_PTR(-ESRCH);
394 data_offsets_size = ALIGN(data_size, sizeof(void *)) +
395 ALIGN(offsets_size, sizeof(void *));
397 if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
398 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
399 "%d: got transaction with invalid size %zd-%zd\n",
400 alloc->pid, data_size, offsets_size);
401 return ERR_PTR(-EINVAL);
403 size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
404 if (size < data_offsets_size || size < extra_buffers_size) {
405 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
406 "%d: got transaction with invalid extra_buffers_size %zd\n",
407 alloc->pid, extra_buffers_size);
408 return ERR_PTR(-EINVAL);
411 alloc->free_async_space < size + sizeof(struct binder_buffer)) {
412 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
413 "%d: binder_alloc_buf size %zd failed, no async space left\n",
415 return ERR_PTR(-ENOSPC);
418 /* Pad 0-size buffers so they get assigned unique addresses */
419 size = max(size, sizeof(void *));
422 buffer = rb_entry(n, struct binder_buffer, rb_node);
423 BUG_ON(!buffer->free);
424 buffer_size = binder_alloc_buffer_size(alloc, buffer);
426 if (size < buffer_size) {
429 } else if (size > buffer_size)
436 if (best_fit == NULL) {
437 size_t allocated_buffers = 0;
438 size_t largest_alloc_size = 0;
439 size_t total_alloc_size = 0;
440 size_t free_buffers = 0;
441 size_t largest_free_size = 0;
442 size_t total_free_size = 0;
444 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
446 buffer = rb_entry(n, struct binder_buffer, rb_node);
447 buffer_size = binder_alloc_buffer_size(alloc, buffer);
449 total_alloc_size += buffer_size;
450 if (buffer_size > largest_alloc_size)
451 largest_alloc_size = buffer_size;
453 for (n = rb_first(&alloc->free_buffers); n != NULL;
455 buffer = rb_entry(n, struct binder_buffer, rb_node);
456 buffer_size = binder_alloc_buffer_size(alloc, buffer);
458 total_free_size += buffer_size;
459 if (buffer_size > largest_free_size)
460 largest_free_size = buffer_size;
462 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
463 "%d: binder_alloc_buf size %zd failed, no address space\n",
465 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
466 "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
467 total_alloc_size, allocated_buffers,
468 largest_alloc_size, total_free_size,
469 free_buffers, largest_free_size);
470 return ERR_PTR(-ENOSPC);
473 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
474 buffer_size = binder_alloc_buffer_size(alloc, buffer);
477 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
478 "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
479 alloc->pid, size, buffer, buffer_size);
481 has_page_addr = (void __user *)
482 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
483 WARN_ON(n && buffer_size != size);
485 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
486 if (end_page_addr > has_page_addr)
487 end_page_addr = has_page_addr;
488 ret = binder_update_page_range(alloc, 1, (void __user *)
489 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
493 if (buffer_size != size) {
494 struct binder_buffer *new_buffer;
496 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
498 pr_err("%s: %d failed to alloc new buffer struct\n",
499 __func__, alloc->pid);
500 goto err_alloc_buf_struct_failed;
502 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
503 list_add(&new_buffer->entry, &buffer->entry);
504 new_buffer->free = 1;
505 binder_insert_free_buffer(alloc, new_buffer);
508 rb_erase(best_fit, &alloc->free_buffers);
510 buffer->allow_user_free = 0;
511 binder_insert_allocated_buffer_locked(alloc, buffer);
512 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
513 "%d: binder_alloc_buf size %zd got %pK\n",
514 alloc->pid, size, buffer);
515 buffer->data_size = data_size;
516 buffer->offsets_size = offsets_size;
517 buffer->async_transaction = is_async;
518 buffer->extra_buffers_size = extra_buffers_size;
520 buffer->oneway_spam_suspect = false;
522 alloc->free_async_space -= size + sizeof(struct binder_buffer);
523 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
524 "%d: binder_alloc_buf size %zd async free %zd\n",
525 alloc->pid, size, alloc->free_async_space);
526 if (alloc->free_async_space < alloc->buffer_size / 10) {
528 * Start detecting spammers once we have less than 20%
529 * of async space left (which is less than 10% of total
532 buffer->oneway_spam_suspect = debug_low_async_space_locked(alloc, pid);
534 alloc->oneway_spam_detected = false;
539 err_alloc_buf_struct_failed:
540 binder_update_page_range(alloc, 0, (void __user *)
541 PAGE_ALIGN((uintptr_t)buffer->user_data),
543 return ERR_PTR(-ENOMEM);
547 * binder_alloc_new_buf() - Allocate a new binder buffer
548 * @alloc: binder_alloc for this proc
549 * @data_size: size of user data buffer
550 * @offsets_size: user specified buffer offset
551 * @extra_buffers_size: size of extra space for meta-data (eg, security context)
552 * @is_async: buffer for async transaction
553 * @pid: pid to attribute allocation to (used for debugging)
555 * Allocate a new buffer given the requested sizes. Returns
556 * the kernel version of the buffer pointer. The size allocated
557 * is the sum of the three given sizes (each rounded up to
558 * pointer-sized boundary)
560 * Return: The allocated buffer or %ERR_PTR(-errno) if error
562 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
565 size_t extra_buffers_size,
569 struct binder_buffer *buffer;
571 mutex_lock(&alloc->mutex);
572 buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
573 extra_buffers_size, is_async, pid);
574 mutex_unlock(&alloc->mutex);
578 static void __user *buffer_start_page(struct binder_buffer *buffer)
580 return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
583 static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
585 return (void __user *)
586 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
589 static void binder_delete_free_buffer(struct binder_alloc *alloc,
590 struct binder_buffer *buffer)
592 struct binder_buffer *prev, *next = NULL;
595 BUG_ON(alloc->buffers.next == &buffer->entry);
596 prev = binder_buffer_prev(buffer);
598 if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
600 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
601 "%d: merge free, buffer %pK share page with %pK\n",
602 alloc->pid, buffer->user_data,
606 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
607 next = binder_buffer_next(buffer);
608 if (buffer_start_page(next) == buffer_start_page(buffer)) {
610 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
611 "%d: merge free, buffer %pK share page with %pK\n",
618 if (PAGE_ALIGNED(buffer->user_data)) {
619 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
620 "%d: merge free, buffer start %pK is page aligned\n",
621 alloc->pid, buffer->user_data);
626 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
627 "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
628 alloc->pid, buffer->user_data,
630 next ? next->user_data : NULL);
631 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
632 buffer_start_page(buffer) + PAGE_SIZE);
634 list_del(&buffer->entry);
638 static void binder_free_buf_locked(struct binder_alloc *alloc,
639 struct binder_buffer *buffer)
641 size_t size, buffer_size;
643 buffer_size = binder_alloc_buffer_size(alloc, buffer);
645 size = ALIGN(buffer->data_size, sizeof(void *)) +
646 ALIGN(buffer->offsets_size, sizeof(void *)) +
647 ALIGN(buffer->extra_buffers_size, sizeof(void *));
649 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
650 "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
651 alloc->pid, buffer, size, buffer_size);
653 BUG_ON(buffer->free);
654 BUG_ON(size > buffer_size);
655 BUG_ON(buffer->transaction != NULL);
656 BUG_ON(buffer->user_data < alloc->buffer);
657 BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
659 if (buffer->async_transaction) {
660 alloc->free_async_space += buffer_size + sizeof(struct binder_buffer);
662 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
663 "%d: binder_free_buf size %zd async free %zd\n",
664 alloc->pid, size, alloc->free_async_space);
667 binder_update_page_range(alloc, 0,
668 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
669 (void __user *)(((uintptr_t)
670 buffer->user_data + buffer_size) & PAGE_MASK));
672 rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
674 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
675 struct binder_buffer *next = binder_buffer_next(buffer);
678 rb_erase(&next->rb_node, &alloc->free_buffers);
679 binder_delete_free_buffer(alloc, next);
682 if (alloc->buffers.next != &buffer->entry) {
683 struct binder_buffer *prev = binder_buffer_prev(buffer);
686 binder_delete_free_buffer(alloc, buffer);
687 rb_erase(&prev->rb_node, &alloc->free_buffers);
691 binder_insert_free_buffer(alloc, buffer);
694 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
695 struct binder_buffer *buffer);
697 * binder_alloc_free_buf() - free a binder buffer
698 * @alloc: binder_alloc for this proc
699 * @buffer: kernel pointer to buffer
701 * Free the buffer allocated via binder_alloc_new_buf()
703 void binder_alloc_free_buf(struct binder_alloc *alloc,
704 struct binder_buffer *buffer)
707 * We could eliminate the call to binder_alloc_clear_buf()
708 * from binder_alloc_deferred_release() by moving this to
709 * binder_free_buf_locked(). However, that could
710 * increase contention for the alloc mutex if clear_on_free
711 * is used frequently for large buffers. The mutex is not
712 * needed for correctness here.
714 if (buffer->clear_on_free) {
715 binder_alloc_clear_buf(alloc, buffer);
716 buffer->clear_on_free = false;
718 mutex_lock(&alloc->mutex);
719 binder_free_buf_locked(alloc, buffer);
720 mutex_unlock(&alloc->mutex);
724 * binder_alloc_mmap_handler() - map virtual address space for proc
725 * @alloc: alloc structure for this proc
726 * @vma: vma passed to mmap()
728 * Called by binder_mmap() to initialize the space specified in
729 * vma for allocating binder buffers
733 * -EBUSY = address space already mapped
734 * -ENOMEM = failed to map memory to given address space
736 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
737 struct vm_area_struct *vma)
740 const char *failure_string;
741 struct binder_buffer *buffer;
743 if (unlikely(vma->vm_mm != alloc->mm)) {
745 failure_string = "invalid vma->vm_mm";
749 mutex_lock(&binder_alloc_mmap_lock);
750 if (alloc->buffer_size) {
752 failure_string = "already mapped";
753 goto err_already_mapped;
755 alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
757 mutex_unlock(&binder_alloc_mmap_lock);
759 alloc->buffer = (void __user *)vma->vm_start;
761 alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
762 sizeof(alloc->pages[0]),
764 if (alloc->pages == NULL) {
766 failure_string = "alloc page array";
767 goto err_alloc_pages_failed;
770 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
773 failure_string = "alloc buffer struct";
774 goto err_alloc_buf_struct_failed;
777 buffer->user_data = alloc->buffer;
778 list_add(&buffer->entry, &alloc->buffers);
780 binder_insert_free_buffer(alloc, buffer);
781 alloc->free_async_space = alloc->buffer_size / 2;
783 /* Signal binder_alloc is fully initialized */
784 binder_alloc_set_vma(alloc, vma);
788 err_alloc_buf_struct_failed:
791 err_alloc_pages_failed:
792 alloc->buffer = NULL;
793 mutex_lock(&binder_alloc_mmap_lock);
794 alloc->buffer_size = 0;
796 mutex_unlock(&binder_alloc_mmap_lock);
798 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
799 "%s: %d %lx-%lx %s failed %d\n", __func__,
800 alloc->pid, vma->vm_start, vma->vm_end,
801 failure_string, ret);
806 void binder_alloc_deferred_release(struct binder_alloc *alloc)
809 int buffers, page_count;
810 struct binder_buffer *buffer;
813 mutex_lock(&alloc->mutex);
816 while ((n = rb_first(&alloc->allocated_buffers))) {
817 buffer = rb_entry(n, struct binder_buffer, rb_node);
819 /* Transaction should already have been freed */
820 BUG_ON(buffer->transaction);
822 if (buffer->clear_on_free) {
823 binder_alloc_clear_buf(alloc, buffer);
824 buffer->clear_on_free = false;
826 binder_free_buf_locked(alloc, buffer);
830 while (!list_empty(&alloc->buffers)) {
831 buffer = list_first_entry(&alloc->buffers,
832 struct binder_buffer, entry);
833 WARN_ON(!buffer->free);
835 list_del(&buffer->entry);
836 WARN_ON_ONCE(!list_empty(&alloc->buffers));
844 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
845 void __user *page_addr;
848 if (!alloc->pages[i].page_ptr)
851 on_lru = list_lru_del(&binder_alloc_lru,
852 &alloc->pages[i].lru);
853 page_addr = alloc->buffer + i * PAGE_SIZE;
854 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
855 "%s: %d: page %d at %pK %s\n",
856 __func__, alloc->pid, i, page_addr,
857 on_lru ? "on lru" : "active");
858 __free_page(alloc->pages[i].page_ptr);
863 mutex_unlock(&alloc->mutex);
867 binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
868 "%s: %d buffers %d, pages %d\n",
869 __func__, alloc->pid, buffers, page_count);
872 static void print_binder_buffer(struct seq_file *m, const char *prefix,
873 struct binder_buffer *buffer)
875 seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
876 prefix, buffer->debug_id, buffer->user_data,
877 buffer->data_size, buffer->offsets_size,
878 buffer->extra_buffers_size,
879 buffer->transaction ? "active" : "delivered");
883 * binder_alloc_print_allocated() - print buffer info
884 * @m: seq_file for output via seq_printf()
885 * @alloc: binder_alloc for this proc
887 * Prints information about every buffer associated with
888 * the binder_alloc state to the given seq_file
890 void binder_alloc_print_allocated(struct seq_file *m,
891 struct binder_alloc *alloc)
895 mutex_lock(&alloc->mutex);
896 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
897 print_binder_buffer(m, " buffer",
898 rb_entry(n, struct binder_buffer, rb_node));
899 mutex_unlock(&alloc->mutex);
903 * binder_alloc_print_pages() - print page usage
904 * @m: seq_file for output via seq_printf()
905 * @alloc: binder_alloc for this proc
907 void binder_alloc_print_pages(struct seq_file *m,
908 struct binder_alloc *alloc)
910 struct binder_lru_page *page;
916 mutex_lock(&alloc->mutex);
918 * Make sure the binder_alloc is fully initialized, otherwise we might
919 * read inconsistent state.
921 if (binder_alloc_get_vma(alloc) != NULL) {
922 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
923 page = &alloc->pages[i];
926 else if (list_empty(&page->lru))
932 mutex_unlock(&alloc->mutex);
933 seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
934 seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);
938 * binder_alloc_get_allocated_count() - return count of buffers
939 * @alloc: binder_alloc for this proc
941 * Return: count of allocated buffers
943 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
948 mutex_lock(&alloc->mutex);
949 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
951 mutex_unlock(&alloc->mutex);
957 * binder_alloc_vma_close() - invalidate address space
958 * @alloc: binder_alloc for this proc
960 * Called from binder_vma_close() when releasing address space.
961 * Clears alloc->vma to prevent new incoming transactions from
962 * allocating more buffers.
964 void binder_alloc_vma_close(struct binder_alloc *alloc)
966 binder_alloc_set_vma(alloc, NULL);
970 * binder_alloc_free_page() - shrinker callback to free pages
971 * @item: item to free
972 * @lock: lock protecting the item
973 * @cb_arg: callback argument
975 * Called from list_lru_walk() in binder_shrink_scan() to free
976 * up pages when the system is under memory pressure.
978 enum lru_status binder_alloc_free_page(struct list_head *item,
979 struct list_lru_one *lru,
984 struct mm_struct *mm = NULL;
985 struct binder_lru_page *page = container_of(item,
986 struct binder_lru_page,
988 struct binder_alloc *alloc;
991 struct vm_area_struct *vma;
994 if (!mutex_trylock(&alloc->mutex))
995 goto err_get_alloc_mutex_failed;
998 goto err_page_already_freed;
1000 index = page - alloc->pages;
1001 page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
1004 if (!mmget_not_zero(mm))
1006 if (!mmap_read_trylock(mm))
1007 goto err_mmap_read_lock_failed;
1008 vma = vma_lookup(mm, page_addr);
1009 if (vma && vma != binder_alloc_get_vma(alloc))
1010 goto err_invalid_vma;
1012 list_lru_isolate(lru, item);
1016 trace_binder_unmap_user_start(alloc, index);
1018 zap_page_range_single(vma, page_addr, PAGE_SIZE, NULL);
1020 trace_binder_unmap_user_end(alloc, index);
1022 mmap_read_unlock(mm);
1025 trace_binder_unmap_kernel_start(alloc, index);
1027 __free_page(page->page_ptr);
1028 page->page_ptr = NULL;
1030 trace_binder_unmap_kernel_end(alloc, index);
1033 mutex_unlock(&alloc->mutex);
1034 return LRU_REMOVED_RETRY;
1037 mmap_read_unlock(mm);
1038 err_mmap_read_lock_failed:
1041 err_page_already_freed:
1042 mutex_unlock(&alloc->mutex);
1043 err_get_alloc_mutex_failed:
1047 static unsigned long
1048 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
1050 return list_lru_count(&binder_alloc_lru);
1053 static unsigned long
1054 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1056 return list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
1057 NULL, sc->nr_to_scan);
1060 static struct shrinker binder_shrinker = {
1061 .count_objects = binder_shrink_count,
1062 .scan_objects = binder_shrink_scan,
1063 .seeks = DEFAULT_SEEKS,
1067 * binder_alloc_init() - called by binder_open() for per-proc initialization
1068 * @alloc: binder_alloc for this proc
1070 * Called from binder_open() to initialize binder_alloc fields for
1073 void binder_alloc_init(struct binder_alloc *alloc)
1075 alloc->pid = current->group_leader->pid;
1076 alloc->mm = current->mm;
1078 mutex_init(&alloc->mutex);
1079 INIT_LIST_HEAD(&alloc->buffers);
1082 int binder_alloc_shrinker_init(void)
1084 int ret = list_lru_init(&binder_alloc_lru);
1087 ret = register_shrinker(&binder_shrinker, "android-binder");
1089 list_lru_destroy(&binder_alloc_lru);
1094 void binder_alloc_shrinker_exit(void)
1096 unregister_shrinker(&binder_shrinker);
1097 list_lru_destroy(&binder_alloc_lru);
1101 * check_buffer() - verify that buffer/offset is safe to access
1102 * @alloc: binder_alloc for this proc
1103 * @buffer: binder buffer to be accessed
1104 * @offset: offset into @buffer data
1105 * @bytes: bytes to access from offset
1107 * Check that the @offset/@bytes are within the size of the given
1108 * @buffer and that the buffer is currently active and not freeable.
1109 * Offsets must also be multiples of sizeof(u32). The kernel is
1110 * allowed to touch the buffer in two cases:
1112 * 1) when the buffer is being created:
1113 * (buffer->free == 0 && buffer->allow_user_free == 0)
1114 * 2) when the buffer is being torn down:
1115 * (buffer->free == 0 && buffer->transaction == NULL).
1117 * Return: true if the buffer is safe to access
1119 static inline bool check_buffer(struct binder_alloc *alloc,
1120 struct binder_buffer *buffer,
1121 binder_size_t offset, size_t bytes)
1123 size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1125 return buffer_size >= bytes &&
1126 offset <= buffer_size - bytes &&
1127 IS_ALIGNED(offset, sizeof(u32)) &&
1129 (!buffer->allow_user_free || !buffer->transaction);
1133 * binder_alloc_get_page() - get kernel pointer for given buffer offset
1134 * @alloc: binder_alloc for this proc
1135 * @buffer: binder buffer to be accessed
1136 * @buffer_offset: offset into @buffer data
1137 * @pgoffp: address to copy final page offset to
1139 * Lookup the struct page corresponding to the address
1140 * at @buffer_offset into @buffer->user_data. If @pgoffp is not
1141 * NULL, the byte-offset into the page is written there.
1143 * The caller is responsible to ensure that the offset points
1144 * to a valid address within the @buffer and that @buffer is
1145 * not freeable by the user. Since it can't be freed, we are
1146 * guaranteed that the corresponding elements of @alloc->pages[]
1149 * Return: struct page
1151 static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1152 struct binder_buffer *buffer,
1153 binder_size_t buffer_offset,
1156 binder_size_t buffer_space_offset = buffer_offset +
1157 (buffer->user_data - alloc->buffer);
1158 pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
1159 size_t index = buffer_space_offset >> PAGE_SHIFT;
1160 struct binder_lru_page *lru_page;
1162 lru_page = &alloc->pages[index];
1164 return lru_page->page_ptr;
1168 * binder_alloc_clear_buf() - zero out buffer
1169 * @alloc: binder_alloc for this proc
1170 * @buffer: binder buffer to be cleared
1172 * memset the given buffer to 0
1174 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
1175 struct binder_buffer *buffer)
1177 size_t bytes = binder_alloc_buffer_size(alloc, buffer);
1178 binder_size_t buffer_offset = 0;
1185 page = binder_alloc_get_page(alloc, buffer,
1186 buffer_offset, &pgoff);
1187 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1188 memset_page(page, pgoff, 0, size);
1190 buffer_offset += size;
1195 * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1196 * @alloc: binder_alloc for this proc
1197 * @buffer: binder buffer to be accessed
1198 * @buffer_offset: offset into @buffer data
1199 * @from: userspace pointer to source buffer
1200 * @bytes: bytes to copy
1202 * Copy bytes from source userspace to target buffer.
1204 * Return: bytes remaining to be copied
1207 binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1208 struct binder_buffer *buffer,
1209 binder_size_t buffer_offset,
1210 const void __user *from,
1213 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1223 page = binder_alloc_get_page(alloc, buffer,
1224 buffer_offset, &pgoff);
1225 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1226 kptr = kmap_local_page(page) + pgoff;
1227 ret = copy_from_user(kptr, from, size);
1230 return bytes - size + ret;
1233 buffer_offset += size;
1238 static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1240 struct binder_buffer *buffer,
1241 binder_size_t buffer_offset,
1245 /* All copies must be 32-bit aligned and 32-bit size */
1246 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1254 page = binder_alloc_get_page(alloc, buffer,
1255 buffer_offset, &pgoff);
1256 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1258 memcpy_to_page(page, pgoff, ptr, size);
1260 memcpy_from_page(ptr, page, pgoff, size);
1264 buffer_offset += size;
1269 int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1270 struct binder_buffer *buffer,
1271 binder_size_t buffer_offset,
1275 return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1279 int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1281 struct binder_buffer *buffer,
1282 binder_size_t buffer_offset,
1285 return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,