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);
352 * Warn if this pid has more than 50 transactions, or more than 50% of
353 * async space (which is 25% of total buffer size). Oneway spam is only
354 * detected when the threshold is exceeded.
356 if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) {
357 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
358 "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n",
359 alloc->pid, pid, num_buffers, total_alloc_size);
360 if (!alloc->oneway_spam_detected) {
361 alloc->oneway_spam_detected = true;
368 static struct binder_buffer *binder_alloc_new_buf_locked(
369 struct binder_alloc *alloc,
372 size_t extra_buffers_size,
376 struct rb_node *n = alloc->free_buffers.rb_node;
377 struct binder_buffer *buffer;
379 struct rb_node *best_fit = NULL;
380 void __user *has_page_addr;
381 void __user *end_page_addr;
382 size_t size, data_offsets_size;
385 /* Check binder_alloc is fully initialized */
386 if (!binder_alloc_get_vma(alloc)) {
387 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
388 "%d: binder_alloc_buf, no vma\n",
390 return ERR_PTR(-ESRCH);
393 data_offsets_size = ALIGN(data_size, sizeof(void *)) +
394 ALIGN(offsets_size, sizeof(void *));
396 if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
397 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
398 "%d: got transaction with invalid size %zd-%zd\n",
399 alloc->pid, data_size, offsets_size);
400 return ERR_PTR(-EINVAL);
402 size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
403 if (size < data_offsets_size || size < extra_buffers_size) {
404 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
405 "%d: got transaction with invalid extra_buffers_size %zd\n",
406 alloc->pid, extra_buffers_size);
407 return ERR_PTR(-EINVAL);
410 /* Pad 0-size buffers so they get assigned unique addresses */
411 size = max(size, sizeof(void *));
413 if (is_async && alloc->free_async_space < size) {
414 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
415 "%d: binder_alloc_buf size %zd failed, no async space left\n",
417 return ERR_PTR(-ENOSPC);
421 buffer = rb_entry(n, struct binder_buffer, rb_node);
422 BUG_ON(!buffer->free);
423 buffer_size = binder_alloc_buffer_size(alloc, buffer);
425 if (size < buffer_size) {
428 } else if (size > buffer_size)
435 if (best_fit == NULL) {
436 size_t allocated_buffers = 0;
437 size_t largest_alloc_size = 0;
438 size_t total_alloc_size = 0;
439 size_t free_buffers = 0;
440 size_t largest_free_size = 0;
441 size_t total_free_size = 0;
443 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
445 buffer = rb_entry(n, struct binder_buffer, rb_node);
446 buffer_size = binder_alloc_buffer_size(alloc, buffer);
448 total_alloc_size += buffer_size;
449 if (buffer_size > largest_alloc_size)
450 largest_alloc_size = buffer_size;
452 for (n = rb_first(&alloc->free_buffers); n != NULL;
454 buffer = rb_entry(n, struct binder_buffer, rb_node);
455 buffer_size = binder_alloc_buffer_size(alloc, buffer);
457 total_free_size += buffer_size;
458 if (buffer_size > largest_free_size)
459 largest_free_size = buffer_size;
461 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
462 "%d: binder_alloc_buf size %zd failed, no address space\n",
464 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
465 "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
466 total_alloc_size, allocated_buffers,
467 largest_alloc_size, total_free_size,
468 free_buffers, largest_free_size);
469 return ERR_PTR(-ENOSPC);
472 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
473 buffer_size = binder_alloc_buffer_size(alloc, buffer);
476 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
477 "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
478 alloc->pid, size, buffer, buffer_size);
480 has_page_addr = (void __user *)
481 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
482 WARN_ON(n && buffer_size != size);
484 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
485 if (end_page_addr > has_page_addr)
486 end_page_addr = has_page_addr;
487 ret = binder_update_page_range(alloc, 1, (void __user *)
488 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
492 if (buffer_size != size) {
493 struct binder_buffer *new_buffer;
495 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
497 pr_err("%s: %d failed to alloc new buffer struct\n",
498 __func__, alloc->pid);
499 goto err_alloc_buf_struct_failed;
501 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
502 list_add(&new_buffer->entry, &buffer->entry);
503 new_buffer->free = 1;
504 binder_insert_free_buffer(alloc, new_buffer);
507 rb_erase(best_fit, &alloc->free_buffers);
509 buffer->allow_user_free = 0;
510 binder_insert_allocated_buffer_locked(alloc, buffer);
511 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
512 "%d: binder_alloc_buf size %zd got %pK\n",
513 alloc->pid, size, buffer);
514 buffer->data_size = data_size;
515 buffer->offsets_size = offsets_size;
516 buffer->async_transaction = is_async;
517 buffer->extra_buffers_size = extra_buffers_size;
519 buffer->oneway_spam_suspect = false;
521 alloc->free_async_space -= size;
522 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
523 "%d: binder_alloc_buf size %zd async free %zd\n",
524 alloc->pid, size, alloc->free_async_space);
525 if (alloc->free_async_space < alloc->buffer_size / 10) {
527 * Start detecting spammers once we have less than 20%
528 * of async space left (which is less than 10% of total
531 buffer->oneway_spam_suspect = debug_low_async_space_locked(alloc, pid);
533 alloc->oneway_spam_detected = false;
538 err_alloc_buf_struct_failed:
539 binder_update_page_range(alloc, 0, (void __user *)
540 PAGE_ALIGN((uintptr_t)buffer->user_data),
542 return ERR_PTR(-ENOMEM);
546 * binder_alloc_new_buf() - Allocate a new binder buffer
547 * @alloc: binder_alloc for this proc
548 * @data_size: size of user data buffer
549 * @offsets_size: user specified buffer offset
550 * @extra_buffers_size: size of extra space for meta-data (eg, security context)
551 * @is_async: buffer for async transaction
552 * @pid: pid to attribute allocation to (used for debugging)
554 * Allocate a new buffer given the requested sizes. Returns
555 * the kernel version of the buffer pointer. The size allocated
556 * is the sum of the three given sizes (each rounded up to
557 * pointer-sized boundary)
559 * Return: The allocated buffer or %ERR_PTR(-errno) if error
561 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
564 size_t extra_buffers_size,
568 struct binder_buffer *buffer;
570 mutex_lock(&alloc->mutex);
571 buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
572 extra_buffers_size, is_async, pid);
573 mutex_unlock(&alloc->mutex);
577 static void __user *buffer_start_page(struct binder_buffer *buffer)
579 return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
582 static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
584 return (void __user *)
585 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
588 static void binder_delete_free_buffer(struct binder_alloc *alloc,
589 struct binder_buffer *buffer)
591 struct binder_buffer *prev, *next = NULL;
594 BUG_ON(alloc->buffers.next == &buffer->entry);
595 prev = binder_buffer_prev(buffer);
597 if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
599 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
600 "%d: merge free, buffer %pK share page with %pK\n",
601 alloc->pid, buffer->user_data,
605 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
606 next = binder_buffer_next(buffer);
607 if (buffer_start_page(next) == buffer_start_page(buffer)) {
609 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
610 "%d: merge free, buffer %pK share page with %pK\n",
617 if (PAGE_ALIGNED(buffer->user_data)) {
618 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
619 "%d: merge free, buffer start %pK is page aligned\n",
620 alloc->pid, buffer->user_data);
625 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
626 "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
627 alloc->pid, buffer->user_data,
629 next ? next->user_data : NULL);
630 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
631 buffer_start_page(buffer) + PAGE_SIZE);
633 list_del(&buffer->entry);
637 static void binder_free_buf_locked(struct binder_alloc *alloc,
638 struct binder_buffer *buffer)
640 size_t size, buffer_size;
642 buffer_size = binder_alloc_buffer_size(alloc, buffer);
644 size = ALIGN(buffer->data_size, sizeof(void *)) +
645 ALIGN(buffer->offsets_size, sizeof(void *)) +
646 ALIGN(buffer->extra_buffers_size, sizeof(void *));
648 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
649 "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
650 alloc->pid, buffer, size, buffer_size);
652 BUG_ON(buffer->free);
653 BUG_ON(size > buffer_size);
654 BUG_ON(buffer->transaction != NULL);
655 BUG_ON(buffer->user_data < alloc->buffer);
656 BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
658 if (buffer->async_transaction) {
659 alloc->free_async_space += buffer_size;
660 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
661 "%d: binder_free_buf size %zd async free %zd\n",
662 alloc->pid, size, alloc->free_async_space);
665 binder_update_page_range(alloc, 0,
666 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
667 (void __user *)(((uintptr_t)
668 buffer->user_data + buffer_size) & PAGE_MASK));
670 rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
672 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
673 struct binder_buffer *next = binder_buffer_next(buffer);
676 rb_erase(&next->rb_node, &alloc->free_buffers);
677 binder_delete_free_buffer(alloc, next);
680 if (alloc->buffers.next != &buffer->entry) {
681 struct binder_buffer *prev = binder_buffer_prev(buffer);
684 binder_delete_free_buffer(alloc, buffer);
685 rb_erase(&prev->rb_node, &alloc->free_buffers);
689 binder_insert_free_buffer(alloc, buffer);
692 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
693 struct binder_buffer *buffer);
695 * binder_alloc_free_buf() - free a binder buffer
696 * @alloc: binder_alloc for this proc
697 * @buffer: kernel pointer to buffer
699 * Free the buffer allocated via binder_alloc_new_buf()
701 void binder_alloc_free_buf(struct binder_alloc *alloc,
702 struct binder_buffer *buffer)
705 * We could eliminate the call to binder_alloc_clear_buf()
706 * from binder_alloc_deferred_release() by moving this to
707 * binder_free_buf_locked(). However, that could
708 * increase contention for the alloc mutex if clear_on_free
709 * is used frequently for large buffers. The mutex is not
710 * needed for correctness here.
712 if (buffer->clear_on_free) {
713 binder_alloc_clear_buf(alloc, buffer);
714 buffer->clear_on_free = false;
716 mutex_lock(&alloc->mutex);
717 binder_free_buf_locked(alloc, buffer);
718 mutex_unlock(&alloc->mutex);
722 * binder_alloc_mmap_handler() - map virtual address space for proc
723 * @alloc: alloc structure for this proc
724 * @vma: vma passed to mmap()
726 * Called by binder_mmap() to initialize the space specified in
727 * vma for allocating binder buffers
731 * -EBUSY = address space already mapped
732 * -ENOMEM = failed to map memory to given address space
734 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
735 struct vm_area_struct *vma)
738 const char *failure_string;
739 struct binder_buffer *buffer;
741 if (unlikely(vma->vm_mm != alloc->mm)) {
743 failure_string = "invalid vma->vm_mm";
747 mutex_lock(&binder_alloc_mmap_lock);
748 if (alloc->buffer_size) {
750 failure_string = "already mapped";
751 goto err_already_mapped;
753 alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
755 mutex_unlock(&binder_alloc_mmap_lock);
757 alloc->buffer = (void __user *)vma->vm_start;
759 alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
760 sizeof(alloc->pages[0]),
762 if (alloc->pages == NULL) {
764 failure_string = "alloc page array";
765 goto err_alloc_pages_failed;
768 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
771 failure_string = "alloc buffer struct";
772 goto err_alloc_buf_struct_failed;
775 buffer->user_data = alloc->buffer;
776 list_add(&buffer->entry, &alloc->buffers);
778 binder_insert_free_buffer(alloc, buffer);
779 alloc->free_async_space = alloc->buffer_size / 2;
781 /* Signal binder_alloc is fully initialized */
782 binder_alloc_set_vma(alloc, vma);
786 err_alloc_buf_struct_failed:
789 err_alloc_pages_failed:
790 alloc->buffer = NULL;
791 mutex_lock(&binder_alloc_mmap_lock);
792 alloc->buffer_size = 0;
794 mutex_unlock(&binder_alloc_mmap_lock);
796 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
797 "%s: %d %lx-%lx %s failed %d\n", __func__,
798 alloc->pid, vma->vm_start, vma->vm_end,
799 failure_string, ret);
804 void binder_alloc_deferred_release(struct binder_alloc *alloc)
807 int buffers, page_count;
808 struct binder_buffer *buffer;
811 mutex_lock(&alloc->mutex);
814 while ((n = rb_first(&alloc->allocated_buffers))) {
815 buffer = rb_entry(n, struct binder_buffer, rb_node);
817 /* Transaction should already have been freed */
818 BUG_ON(buffer->transaction);
820 if (buffer->clear_on_free) {
821 binder_alloc_clear_buf(alloc, buffer);
822 buffer->clear_on_free = false;
824 binder_free_buf_locked(alloc, buffer);
828 while (!list_empty(&alloc->buffers)) {
829 buffer = list_first_entry(&alloc->buffers,
830 struct binder_buffer, entry);
831 WARN_ON(!buffer->free);
833 list_del(&buffer->entry);
834 WARN_ON_ONCE(!list_empty(&alloc->buffers));
842 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
843 void __user *page_addr;
846 if (!alloc->pages[i].page_ptr)
849 on_lru = list_lru_del(&binder_alloc_lru,
850 &alloc->pages[i].lru);
851 page_addr = alloc->buffer + i * PAGE_SIZE;
852 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
853 "%s: %d: page %d at %pK %s\n",
854 __func__, alloc->pid, i, page_addr,
855 on_lru ? "on lru" : "active");
856 __free_page(alloc->pages[i].page_ptr);
861 mutex_unlock(&alloc->mutex);
865 binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
866 "%s: %d buffers %d, pages %d\n",
867 __func__, alloc->pid, buffers, page_count);
870 static void print_binder_buffer(struct seq_file *m, const char *prefix,
871 struct binder_buffer *buffer)
873 seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
874 prefix, buffer->debug_id, buffer->user_data,
875 buffer->data_size, buffer->offsets_size,
876 buffer->extra_buffers_size,
877 buffer->transaction ? "active" : "delivered");
881 * binder_alloc_print_allocated() - print buffer info
882 * @m: seq_file for output via seq_printf()
883 * @alloc: binder_alloc for this proc
885 * Prints information about every buffer associated with
886 * the binder_alloc state to the given seq_file
888 void binder_alloc_print_allocated(struct seq_file *m,
889 struct binder_alloc *alloc)
893 mutex_lock(&alloc->mutex);
894 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
895 print_binder_buffer(m, " buffer",
896 rb_entry(n, struct binder_buffer, rb_node));
897 mutex_unlock(&alloc->mutex);
901 * binder_alloc_print_pages() - print page usage
902 * @m: seq_file for output via seq_printf()
903 * @alloc: binder_alloc for this proc
905 void binder_alloc_print_pages(struct seq_file *m,
906 struct binder_alloc *alloc)
908 struct binder_lru_page *page;
914 mutex_lock(&alloc->mutex);
916 * Make sure the binder_alloc is fully initialized, otherwise we might
917 * read inconsistent state.
919 if (binder_alloc_get_vma(alloc) != NULL) {
920 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
921 page = &alloc->pages[i];
924 else if (list_empty(&page->lru))
930 mutex_unlock(&alloc->mutex);
931 seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
932 seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);
936 * binder_alloc_get_allocated_count() - return count of buffers
937 * @alloc: binder_alloc for this proc
939 * Return: count of allocated buffers
941 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
946 mutex_lock(&alloc->mutex);
947 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
949 mutex_unlock(&alloc->mutex);
955 * binder_alloc_vma_close() - invalidate address space
956 * @alloc: binder_alloc for this proc
958 * Called from binder_vma_close() when releasing address space.
959 * Clears alloc->vma to prevent new incoming transactions from
960 * allocating more buffers.
962 void binder_alloc_vma_close(struct binder_alloc *alloc)
964 binder_alloc_set_vma(alloc, NULL);
968 * binder_alloc_free_page() - shrinker callback to free pages
969 * @item: item to free
970 * @lock: lock protecting the item
971 * @cb_arg: callback argument
973 * Called from list_lru_walk() in binder_shrink_scan() to free
974 * up pages when the system is under memory pressure.
976 enum lru_status binder_alloc_free_page(struct list_head *item,
977 struct list_lru_one *lru,
982 struct mm_struct *mm = NULL;
983 struct binder_lru_page *page = container_of(item,
984 struct binder_lru_page,
986 struct binder_alloc *alloc;
989 struct vm_area_struct *vma;
992 if (!mutex_trylock(&alloc->mutex))
993 goto err_get_alloc_mutex_failed;
996 goto err_page_already_freed;
998 index = page - alloc->pages;
999 page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
1002 if (!mmget_not_zero(mm))
1004 if (!mmap_read_trylock(mm))
1005 goto err_mmap_read_lock_failed;
1006 vma = vma_lookup(mm, page_addr);
1007 if (vma && vma != binder_alloc_get_vma(alloc))
1008 goto err_invalid_vma;
1010 list_lru_isolate(lru, item);
1014 trace_binder_unmap_user_start(alloc, index);
1016 zap_page_range_single(vma, page_addr, PAGE_SIZE, NULL);
1018 trace_binder_unmap_user_end(alloc, index);
1020 mmap_read_unlock(mm);
1023 trace_binder_unmap_kernel_start(alloc, index);
1025 __free_page(page->page_ptr);
1026 page->page_ptr = NULL;
1028 trace_binder_unmap_kernel_end(alloc, index);
1031 mutex_unlock(&alloc->mutex);
1032 return LRU_REMOVED_RETRY;
1035 mmap_read_unlock(mm);
1036 err_mmap_read_lock_failed:
1039 err_page_already_freed:
1040 mutex_unlock(&alloc->mutex);
1041 err_get_alloc_mutex_failed:
1045 static unsigned long
1046 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
1048 return list_lru_count(&binder_alloc_lru);
1051 static unsigned long
1052 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1054 return list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
1055 NULL, sc->nr_to_scan);
1058 static struct shrinker binder_shrinker = {
1059 .count_objects = binder_shrink_count,
1060 .scan_objects = binder_shrink_scan,
1061 .seeks = DEFAULT_SEEKS,
1065 * binder_alloc_init() - called by binder_open() for per-proc initialization
1066 * @alloc: binder_alloc for this proc
1068 * Called from binder_open() to initialize binder_alloc fields for
1071 void binder_alloc_init(struct binder_alloc *alloc)
1073 alloc->pid = current->group_leader->pid;
1074 alloc->mm = current->mm;
1076 mutex_init(&alloc->mutex);
1077 INIT_LIST_HEAD(&alloc->buffers);
1080 int binder_alloc_shrinker_init(void)
1082 int ret = list_lru_init(&binder_alloc_lru);
1085 ret = register_shrinker(&binder_shrinker, "android-binder");
1087 list_lru_destroy(&binder_alloc_lru);
1092 void binder_alloc_shrinker_exit(void)
1094 unregister_shrinker(&binder_shrinker);
1095 list_lru_destroy(&binder_alloc_lru);
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
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:
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).
1115 * Return: true if the buffer is safe to access
1117 static inline bool check_buffer(struct binder_alloc *alloc,
1118 struct binder_buffer *buffer,
1119 binder_size_t offset, size_t bytes)
1121 size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1123 return buffer_size >= bytes &&
1124 offset <= buffer_size - bytes &&
1125 IS_ALIGNED(offset, sizeof(u32)) &&
1127 (!buffer->allow_user_free || !buffer->transaction);
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
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.
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[]
1147 * Return: struct page
1149 static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1150 struct binder_buffer *buffer,
1151 binder_size_t buffer_offset,
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;
1160 lru_page = &alloc->pages[index];
1162 return lru_page->page_ptr;
1166 * binder_alloc_clear_buf() - zero out buffer
1167 * @alloc: binder_alloc for this proc
1168 * @buffer: binder buffer to be cleared
1170 * memset the given buffer to 0
1172 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
1173 struct binder_buffer *buffer)
1175 size_t bytes = binder_alloc_buffer_size(alloc, buffer);
1176 binder_size_t buffer_offset = 0;
1183 page = binder_alloc_get_page(alloc, buffer,
1184 buffer_offset, &pgoff);
1185 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1186 memset_page(page, pgoff, 0, size);
1188 buffer_offset += size;
1193 * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1194 * @alloc: binder_alloc for this proc
1195 * @buffer: binder buffer to be accessed
1196 * @buffer_offset: offset into @buffer data
1197 * @from: userspace pointer to source buffer
1198 * @bytes: bytes to copy
1200 * Copy bytes from source userspace to target buffer.
1202 * Return: bytes remaining to be copied
1205 binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1206 struct binder_buffer *buffer,
1207 binder_size_t buffer_offset,
1208 const void __user *from,
1211 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1221 page = binder_alloc_get_page(alloc, buffer,
1222 buffer_offset, &pgoff);
1223 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1224 kptr = kmap_local_page(page) + pgoff;
1225 ret = copy_from_user(kptr, from, size);
1228 return bytes - size + ret;
1231 buffer_offset += size;
1236 static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1238 struct binder_buffer *buffer,
1239 binder_size_t buffer_offset,
1243 /* All copies must be 32-bit aligned and 32-bit size */
1244 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1252 page = binder_alloc_get_page(alloc, buffer,
1253 buffer_offset, &pgoff);
1254 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1256 memcpy_to_page(page, pgoff, ptr, size);
1258 memcpy_from_page(ptr, page, pgoff, size);
1262 buffer_offset += size;
1267 int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1268 struct binder_buffer *buffer,
1269 binder_size_t buffer_offset,
1273 return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1277 int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1279 struct binder_buffer *buffer,
1280 binder_size_t buffer_offset,
1283 return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,