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_freelist;
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,
128 unsigned long user_ptr)
130 struct rb_node *n = alloc->allocated_buffers.rb_node;
131 struct binder_buffer *buffer;
134 buffer = rb_entry(n, struct binder_buffer, rb_node);
135 BUG_ON(buffer->free);
137 if (user_ptr < buffer->user_data) {
139 } else if (user_ptr > buffer->user_data) {
143 * Guard against user threads attempting to
144 * free the buffer when in use by kernel or
145 * after it's already been freed.
147 if (!buffer->allow_user_free)
148 return ERR_PTR(-EPERM);
149 buffer->allow_user_free = 0;
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
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
165 * Return: Pointer to buffer or NULL
167 struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
168 unsigned long user_ptr)
170 struct binder_buffer *buffer;
172 spin_lock(&alloc->lock);
173 buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
174 spin_unlock(&alloc->lock);
179 binder_set_installed_page(struct binder_lru_page *lru_page,
182 /* Pairs with acquire in binder_get_installed_page() */
183 smp_store_release(&lru_page->page_ptr, page);
186 static inline struct page *
187 binder_get_installed_page(struct binder_lru_page *lru_page)
189 /* Pairs with release in binder_set_installed_page() */
190 return smp_load_acquire(&lru_page->page_ptr);
193 static void binder_lru_freelist_add(struct binder_alloc *alloc,
194 unsigned long start, unsigned long end)
196 struct binder_lru_page *page;
197 unsigned long page_addr;
199 trace_binder_update_page_range(alloc, false, start, end);
201 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
205 index = (page_addr - alloc->buffer) / PAGE_SIZE;
206 page = &alloc->pages[index];
208 if (!binder_get_installed_page(page))
211 trace_binder_free_lru_start(alloc, index);
213 ret = list_lru_add_obj(&binder_freelist, &page->lru);
216 trace_binder_free_lru_end(alloc, index);
220 static int binder_install_single_page(struct binder_alloc *alloc,
221 struct binder_lru_page *lru_page,
227 if (!mmget_not_zero(alloc->mm))
231 * Protected with mmap_sem in write mode as multiple tasks
232 * might race to install the same page.
234 mmap_write_lock(alloc->mm);
235 if (binder_get_installed_page(lru_page))
239 pr_err("%d: %s failed, no vma\n", alloc->pid, __func__);
244 page = alloc_page(GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
246 pr_err("%d: failed to allocate page\n", alloc->pid);
251 ret = vm_insert_page(alloc->vma, addr, page);
253 pr_err("%d: %s failed to insert page at offset %lx with %d\n",
254 alloc->pid, __func__, addr - alloc->buffer, ret);
260 /* Mark page installation complete and safe to use */
261 binder_set_installed_page(lru_page, page);
263 mmap_write_unlock(alloc->mm);
264 mmput_async(alloc->mm);
268 static int binder_install_buffer_pages(struct binder_alloc *alloc,
269 struct binder_buffer *buffer,
272 struct binder_lru_page *page;
273 unsigned long start, final;
274 unsigned long page_addr;
276 start = buffer->user_data & PAGE_MASK;
277 final = PAGE_ALIGN(buffer->user_data + size);
279 for (page_addr = start; page_addr < final; page_addr += PAGE_SIZE) {
283 index = (page_addr - alloc->buffer) / PAGE_SIZE;
284 page = &alloc->pages[index];
286 if (binder_get_installed_page(page))
289 trace_binder_alloc_page_start(alloc, index);
291 ret = binder_install_single_page(alloc, page, page_addr);
295 trace_binder_alloc_page_end(alloc, index);
301 /* The range of pages should exclude those shared with other buffers */
302 static void binder_lru_freelist_del(struct binder_alloc *alloc,
303 unsigned long start, unsigned long end)
305 struct binder_lru_page *page;
306 unsigned long page_addr;
308 trace_binder_update_page_range(alloc, true, start, end);
310 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
314 index = (page_addr - alloc->buffer) / PAGE_SIZE;
315 page = &alloc->pages[index];
317 if (page->page_ptr) {
318 trace_binder_alloc_lru_start(alloc, index);
320 on_lru = list_lru_del_obj(&binder_freelist, &page->lru);
323 trace_binder_alloc_lru_end(alloc, index);
327 if (index + 1 > alloc->pages_high)
328 alloc->pages_high = index + 1;
332 static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
333 struct vm_area_struct *vma)
335 /* pairs with smp_load_acquire in binder_alloc_get_vma() */
336 smp_store_release(&alloc->vma, vma);
339 static inline struct vm_area_struct *binder_alloc_get_vma(
340 struct binder_alloc *alloc)
342 /* pairs with smp_store_release in binder_alloc_set_vma() */
343 return smp_load_acquire(&alloc->vma);
346 static void debug_no_space_locked(struct binder_alloc *alloc)
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;
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);
362 total_alloc_size += buffer_size;
363 if (buffer_size > largest_alloc_size)
364 largest_alloc_size = buffer_size;
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);
371 total_free_size += buffer_size;
372 if (buffer_size > largest_free_size)
373 largest_free_size = buffer_size;
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);
383 static bool debug_low_async_space_locked(struct binder_alloc *alloc)
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.
392 struct binder_buffer *buffer;
393 size_t total_alloc_size = 0;
394 int pid = current->tgid;
395 size_t num_buffers = 0;
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).
402 if (alloc->free_async_space >= alloc->buffer_size / 10) {
403 alloc->oneway_spam_detected = false;
407 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
409 buffer = rb_entry(n, struct binder_buffer, rb_node);
410 if (buffer->pid != pid)
412 if (!buffer->async_transaction)
414 total_alloc_size += binder_alloc_buffer_size(alloc, buffer);
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.
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;
435 /* Callers preallocate @new_buffer, it is freed by this function if unused */
436 static struct binder_buffer *binder_alloc_new_buf_locked(
437 struct binder_alloc *alloc,
438 struct binder_buffer *new_buffer,
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;
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",
453 buffer = ERR_PTR(-ENOSPC);
458 buffer = rb_entry(n, struct binder_buffer, rb_node);
459 BUG_ON(!buffer->free);
460 buffer_size = binder_alloc_buffer_size(alloc, buffer);
462 if (size < buffer_size) {
465 } else if (size > buffer_size) {
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",
477 debug_no_space_locked(alloc);
478 buffer = ERR_PTR(-ENOSPC);
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);
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);
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);
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.
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));
510 rb_erase(&buffer->rb_node, &alloc->free_buffers);
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;
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;
526 /* Discard possibly unused new_buffer */
531 /* Calculate the sanitized total size, returns 0 for invalid request */
532 static inline size_t sanitized_size(size_t data_size,
534 size_t extra_buffers_size)
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)
543 total = tmp + ALIGN(extra_buffers_size, sizeof(void *));
544 if (total < tmp || total < extra_buffers_size)
547 /* Pad 0-sized buffers so they get a unique address */
548 total = max(total, sizeof(void *));
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
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)
566 * Return: The allocated buffer or %ERR_PTR(-errno) if error
568 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
571 size_t extra_buffers_size,
574 struct binder_buffer *buffer, *next;
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",
583 return ERR_PTR(-ESRCH);
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,
592 return ERR_PTR(-EINVAL);
595 /* Preallocate the next buffer */
596 next = kzalloc(sizeof(*next), GFP_KERNEL);
598 return ERR_PTR(-ENOMEM);
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);
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);
613 ret = binder_install_buffer_pages(alloc, buffer, size);
615 binder_alloc_free_buf(alloc, buffer);
616 buffer = ERR_PTR(ret);
622 static unsigned long buffer_start_page(struct binder_buffer *buffer)
624 return buffer->user_data & PAGE_MASK;
627 static unsigned long prev_buffer_end_page(struct binder_buffer *buffer)
629 return (buffer->user_data - 1) & PAGE_MASK;
632 static void binder_delete_free_buffer(struct binder_alloc *alloc,
633 struct binder_buffer *buffer)
635 struct binder_buffer *prev, *next;
637 if (PAGE_ALIGNED(buffer->user_data))
640 BUG_ON(alloc->buffers.next == &buffer->entry);
641 prev = binder_buffer_prev(buffer);
643 if (prev_buffer_end_page(prev) == buffer_start_page(buffer))
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))
652 binder_lru_freelist_add(alloc, buffer_start_page(buffer),
653 buffer_start_page(buffer) + PAGE_SIZE);
655 list_del(&buffer->entry);
659 static void binder_free_buf_locked(struct binder_alloc *alloc,
660 struct binder_buffer *buffer)
662 size_t size, buffer_size;
664 buffer_size = binder_alloc_buffer_size(alloc, buffer);
666 size = ALIGN(buffer->data_size, sizeof(void *)) +
667 ALIGN(buffer->offsets_size, sizeof(void *)) +
668 ALIGN(buffer->extra_buffers_size, sizeof(void *));
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);
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);
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);
687 binder_lru_freelist_add(alloc, PAGE_ALIGN(buffer->user_data),
688 (buffer->user_data + buffer_size) & PAGE_MASK);
690 rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
692 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
693 struct binder_buffer *next = binder_buffer_next(buffer);
696 rb_erase(&next->rb_node, &alloc->free_buffers);
697 binder_delete_free_buffer(alloc, next);
700 if (alloc->buffers.next != &buffer->entry) {
701 struct binder_buffer *prev = binder_buffer_prev(buffer);
704 binder_delete_free_buffer(alloc, buffer);
705 rb_erase(&prev->rb_node, &alloc->free_buffers);
709 binder_insert_free_buffer(alloc, buffer);
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
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.
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[]
729 * Return: struct page
731 static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
732 struct binder_buffer *buffer,
733 binder_size_t buffer_offset,
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;
742 lru_page = &alloc->pages[index];
744 return lru_page->page_ptr;
748 * binder_alloc_clear_buf() - zero out buffer
749 * @alloc: binder_alloc for this proc
750 * @buffer: binder buffer to be cleared
752 * memset the given buffer to 0
754 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
755 struct binder_buffer *buffer)
757 size_t bytes = binder_alloc_buffer_size(alloc, buffer);
758 binder_size_t buffer_offset = 0;
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);
770 buffer_offset += size;
775 * binder_alloc_free_buf() - free a binder buffer
776 * @alloc: binder_alloc for this proc
777 * @buffer: kernel pointer to buffer
779 * Free the buffer allocated via binder_alloc_new_buf()
781 void binder_alloc_free_buf(struct binder_alloc *alloc,
782 struct binder_buffer *buffer)
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.
792 if (buffer->clear_on_free) {
793 binder_alloc_clear_buf(alloc, buffer);
794 buffer->clear_on_free = false;
796 spin_lock(&alloc->lock);
797 binder_free_buf_locked(alloc, buffer);
798 spin_unlock(&alloc->lock);
802 * binder_alloc_mmap_handler() - map virtual address space for proc
803 * @alloc: alloc structure for this proc
804 * @vma: vma passed to mmap()
806 * Called by binder_mmap() to initialize the space specified in
807 * vma for allocating binder buffers
811 * -EBUSY = address space already mapped
812 * -ENOMEM = failed to map memory to given address space
814 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
815 struct vm_area_struct *vma)
817 struct binder_buffer *buffer;
818 const char *failure_string;
821 if (unlikely(vma->vm_mm != alloc->mm)) {
823 failure_string = "invalid vma->vm_mm";
827 mutex_lock(&binder_alloc_mmap_lock);
828 if (alloc->buffer_size) {
830 failure_string = "already mapped";
831 goto err_already_mapped;
833 alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
835 mutex_unlock(&binder_alloc_mmap_lock);
837 alloc->buffer = vma->vm_start;
839 alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
840 sizeof(alloc->pages[0]),
842 if (alloc->pages == NULL) {
844 failure_string = "alloc page array";
845 goto err_alloc_pages_failed;
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);
853 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
856 failure_string = "alloc buffer struct";
857 goto err_alloc_buf_struct_failed;
860 buffer->user_data = alloc->buffer;
861 list_add(&buffer->entry, &alloc->buffers);
863 binder_insert_free_buffer(alloc, buffer);
864 alloc->free_async_space = alloc->buffer_size / 2;
866 /* Signal binder_alloc is fully initialized */
867 binder_alloc_set_vma(alloc, vma);
871 err_alloc_buf_struct_failed:
874 err_alloc_pages_failed:
876 mutex_lock(&binder_alloc_mmap_lock);
877 alloc->buffer_size = 0;
879 mutex_unlock(&binder_alloc_mmap_lock);
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);
889 void binder_alloc_deferred_release(struct binder_alloc *alloc)
892 int buffers, page_count;
893 struct binder_buffer *buffer;
896 spin_lock(&alloc->lock);
899 while ((n = rb_first(&alloc->allocated_buffers))) {
900 buffer = rb_entry(n, struct binder_buffer, rb_node);
902 /* Transaction should already have been freed */
903 BUG_ON(buffer->transaction);
905 if (buffer->clear_on_free) {
906 binder_alloc_clear_buf(alloc, buffer);
907 buffer->clear_on_free = false;
909 binder_free_buf_locked(alloc, buffer);
913 while (!list_empty(&alloc->buffers)) {
914 buffer = list_first_entry(&alloc->buffers,
915 struct binder_buffer, entry);
916 WARN_ON(!buffer->free);
918 list_del(&buffer->entry);
919 WARN_ON_ONCE(!list_empty(&alloc->buffers));
927 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
928 unsigned long page_addr;
931 if (!alloc->pages[i].page_ptr)
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);
946 spin_unlock(&alloc->lock);
950 binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
951 "%s: %d buffers %d, pages %d\n",
952 __func__, alloc->pid, buffers, page_count);
956 * binder_alloc_print_allocated() - print buffer info
957 * @m: seq_file for output via seq_printf()
958 * @alloc: binder_alloc for this proc
960 * Prints information about every buffer associated with
961 * the binder_alloc state to the given seq_file
963 void binder_alloc_print_allocated(struct seq_file *m,
964 struct binder_alloc *alloc)
966 struct binder_buffer *buffer;
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",
974 buffer->user_data - alloc->buffer,
975 buffer->data_size, buffer->offsets_size,
976 buffer->extra_buffers_size,
977 buffer->transaction ? "active" : "delivered");
979 spin_unlock(&alloc->lock);
983 * binder_alloc_print_pages() - print page usage
984 * @m: seq_file for output via seq_printf()
985 * @alloc: binder_alloc for this proc
987 void binder_alloc_print_pages(struct seq_file *m,
988 struct binder_alloc *alloc)
990 struct binder_lru_page *page;
996 spin_lock(&alloc->lock);
998 * Make sure the binder_alloc is fully initialized, otherwise we might
999 * read inconsistent state.
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)
1006 else if (list_empty(&page->lru))
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);
1018 * binder_alloc_get_allocated_count() - return count of buffers
1019 * @alloc: binder_alloc for this proc
1021 * Return: count of allocated buffers
1023 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
1028 spin_lock(&alloc->lock);
1029 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
1031 spin_unlock(&alloc->lock);
1037 * binder_alloc_vma_close() - invalidate address space
1038 * @alloc: binder_alloc for this proc
1040 * Called from binder_vma_close() when releasing address space.
1041 * Clears alloc->vma to prevent new incoming transactions from
1042 * allocating more buffers.
1044 void binder_alloc_vma_close(struct binder_alloc *alloc)
1046 binder_alloc_set_vma(alloc, NULL);
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
1055 * Called from list_lru_walk() in binder_shrink_scan() to free
1056 * up pages when the system is under memory pressure.
1058 enum lru_status binder_alloc_free_page(struct list_head *item,
1059 struct list_lru_one *lru,
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;
1072 if (!mmget_not_zero(mm))
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;
1081 index = page - alloc->pages;
1082 page_addr = alloc->buffer + index * PAGE_SIZE;
1084 vma = vma_lookup(mm, page_addr);
1085 if (vma && vma != binder_alloc_get_vma(alloc))
1086 goto err_invalid_vma;
1088 trace_binder_unmap_kernel_start(alloc, index);
1090 page_to_free = page->page_ptr;
1091 page->page_ptr = NULL;
1093 trace_binder_unmap_kernel_end(alloc, index);
1095 list_lru_isolate(lru, item);
1096 spin_unlock(&alloc->lock);
1100 trace_binder_unmap_user_start(alloc, index);
1102 zap_page_range_single(vma, page_addr, PAGE_SIZE, NULL);
1104 trace_binder_unmap_user_end(alloc, index);
1107 mmap_read_unlock(mm);
1109 __free_page(page_to_free);
1112 return LRU_REMOVED_RETRY;
1115 err_page_already_freed:
1116 spin_unlock(&alloc->lock);
1117 err_get_alloc_lock_failed:
1118 mmap_read_unlock(mm);
1119 err_mmap_read_lock_failed:
1125 static unsigned long
1126 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
1128 return list_lru_count(&binder_freelist);
1131 static unsigned long
1132 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1134 return list_lru_walk(&binder_freelist, binder_alloc_free_page,
1135 NULL, sc->nr_to_scan);
1138 static struct shrinker *binder_shrinker;
1141 * binder_alloc_init() - called by binder_open() for per-proc initialization
1142 * @alloc: binder_alloc for this proc
1144 * Called from binder_open() to initialize binder_alloc fields for
1147 void binder_alloc_init(struct binder_alloc *alloc)
1149 alloc->pid = current->group_leader->pid;
1150 alloc->mm = current->mm;
1152 spin_lock_init(&alloc->lock);
1153 INIT_LIST_HEAD(&alloc->buffers);
1156 int binder_alloc_shrinker_init(void)
1160 ret = list_lru_init(&binder_freelist);
1164 binder_shrinker = shrinker_alloc(0, "android-binder");
1165 if (!binder_shrinker) {
1166 list_lru_destroy(&binder_freelist);
1170 binder_shrinker->count_objects = binder_shrink_count;
1171 binder_shrinker->scan_objects = binder_shrink_scan;
1173 shrinker_register(binder_shrinker);
1178 void binder_alloc_shrinker_exit(void)
1180 shrinker_free(binder_shrinker);
1181 list_lru_destroy(&binder_freelist);
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
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:
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).
1201 * Return: true if the buffer is safe to access
1203 static inline bool check_buffer(struct binder_alloc *alloc,
1204 struct binder_buffer *buffer,
1205 binder_size_t offset, size_t bytes)
1207 size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1209 return buffer_size >= bytes &&
1210 offset <= buffer_size - bytes &&
1211 IS_ALIGNED(offset, sizeof(u32)) &&
1213 (!buffer->allow_user_free || !buffer->transaction);
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
1224 * Copy bytes from source userspace to target buffer.
1226 * Return: bytes remaining to be copied
1229 binder_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,
1235 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
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);
1252 return bytes - size + ret;
1255 buffer_offset += size;
1260 static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1262 struct binder_buffer *buffer,
1263 binder_size_t buffer_offset,
1267 /* All copies must be 32-bit aligned and 32-bit size */
1268 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1276 page = binder_alloc_get_page(alloc, buffer,
1277 buffer_offset, &pgoff);
1278 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1280 memcpy_to_page(page, pgoff, ptr, size);
1282 memcpy_from_page(ptr, page, pgoff, size);
1286 buffer_offset += size;
1291 int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1292 struct binder_buffer *buffer,
1293 binder_size_t buffer_offset,
1297 return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1301 int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1303 struct binder_buffer *buffer,
1304 binder_size_t buffer_offset,
1307 return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,