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->vma_vm_mm))
212 mm = alloc->vma_vm_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_read_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_read_unlock(mm);
309 return vma ? -ENOMEM : -ESRCH;
313 static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
314 struct vm_area_struct *vma)
317 alloc->vma_vm_mm = vma->vm_mm;
319 * If we see alloc->vma is not NULL, buffer data structures set up
320 * completely. Look at smp_rmb side binder_alloc_get_vma.
321 * We also want to guarantee new alloc->vma_vm_mm is always visible
322 * if alloc->vma is set.
328 static inline struct vm_area_struct *binder_alloc_get_vma(
329 struct binder_alloc *alloc)
331 struct vm_area_struct *vma = NULL;
334 /* Look at description in binder_alloc_set_vma */
341 static void debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
344 * Find the amount and size of buffers allocated by the current caller;
345 * The idea is that once we cross the threshold, whoever is responsible
346 * for the low async space is likely to try to send another async txn,
347 * and at some point we'll catch them in the act. This is more efficient
348 * than keeping a map per pid.
351 struct binder_buffer *buffer;
352 size_t total_alloc_size = 0;
353 size_t num_buffers = 0;
355 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
357 buffer = rb_entry(n, struct binder_buffer, rb_node);
358 if (buffer->pid != pid)
360 if (!buffer->async_transaction)
362 total_alloc_size += binder_alloc_buffer_size(alloc, buffer)
363 + sizeof(struct binder_buffer);
368 * Warn if this pid has more than 50 transactions, or more than 50% of
369 * async space (which is 25% of total buffer size).
371 if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) {
372 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
373 "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n",
374 alloc->pid, pid, num_buffers, total_alloc_size);
378 static struct binder_buffer *binder_alloc_new_buf_locked(
379 struct binder_alloc *alloc,
382 size_t extra_buffers_size,
386 struct rb_node *n = alloc->free_buffers.rb_node;
387 struct binder_buffer *buffer;
389 struct rb_node *best_fit = NULL;
390 void __user *has_page_addr;
391 void __user *end_page_addr;
392 size_t size, data_offsets_size;
395 if (!binder_alloc_get_vma(alloc)) {
396 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
397 "%d: binder_alloc_buf, no vma\n",
399 return ERR_PTR(-ESRCH);
402 data_offsets_size = ALIGN(data_size, sizeof(void *)) +
403 ALIGN(offsets_size, sizeof(void *));
405 if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
406 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
407 "%d: got transaction with invalid size %zd-%zd\n",
408 alloc->pid, data_size, offsets_size);
409 return ERR_PTR(-EINVAL);
411 size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
412 if (size < data_offsets_size || size < extra_buffers_size) {
413 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
414 "%d: got transaction with invalid extra_buffers_size %zd\n",
415 alloc->pid, extra_buffers_size);
416 return ERR_PTR(-EINVAL);
419 alloc->free_async_space < size + sizeof(struct binder_buffer)) {
420 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
421 "%d: binder_alloc_buf size %zd failed, no async space left\n",
423 return ERR_PTR(-ENOSPC);
426 /* Pad 0-size buffers so they get assigned unique addresses */
427 size = max(size, sizeof(void *));
430 buffer = rb_entry(n, struct binder_buffer, rb_node);
431 BUG_ON(!buffer->free);
432 buffer_size = binder_alloc_buffer_size(alloc, buffer);
434 if (size < buffer_size) {
437 } else if (size > buffer_size)
444 if (best_fit == NULL) {
445 size_t allocated_buffers = 0;
446 size_t largest_alloc_size = 0;
447 size_t total_alloc_size = 0;
448 size_t free_buffers = 0;
449 size_t largest_free_size = 0;
450 size_t total_free_size = 0;
452 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
454 buffer = rb_entry(n, struct binder_buffer, rb_node);
455 buffer_size = binder_alloc_buffer_size(alloc, buffer);
457 total_alloc_size += buffer_size;
458 if (buffer_size > largest_alloc_size)
459 largest_alloc_size = buffer_size;
461 for (n = rb_first(&alloc->free_buffers); n != NULL;
463 buffer = rb_entry(n, struct binder_buffer, rb_node);
464 buffer_size = binder_alloc_buffer_size(alloc, buffer);
466 total_free_size += buffer_size;
467 if (buffer_size > largest_free_size)
468 largest_free_size = buffer_size;
470 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
471 "%d: binder_alloc_buf size %zd failed, no address space\n",
473 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
474 "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
475 total_alloc_size, allocated_buffers,
476 largest_alloc_size, total_free_size,
477 free_buffers, largest_free_size);
478 return ERR_PTR(-ENOSPC);
481 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
482 buffer_size = binder_alloc_buffer_size(alloc, buffer);
485 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
486 "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
487 alloc->pid, size, buffer, buffer_size);
489 has_page_addr = (void __user *)
490 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
491 WARN_ON(n && buffer_size != size);
493 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
494 if (end_page_addr > has_page_addr)
495 end_page_addr = has_page_addr;
496 ret = binder_update_page_range(alloc, 1, (void __user *)
497 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
501 if (buffer_size != size) {
502 struct binder_buffer *new_buffer;
504 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
506 pr_err("%s: %d failed to alloc new buffer struct\n",
507 __func__, alloc->pid);
508 goto err_alloc_buf_struct_failed;
510 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
511 list_add(&new_buffer->entry, &buffer->entry);
512 new_buffer->free = 1;
513 binder_insert_free_buffer(alloc, new_buffer);
516 rb_erase(best_fit, &alloc->free_buffers);
518 buffer->allow_user_free = 0;
519 binder_insert_allocated_buffer_locked(alloc, buffer);
520 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
521 "%d: binder_alloc_buf size %zd got %pK\n",
522 alloc->pid, size, buffer);
523 buffer->data_size = data_size;
524 buffer->offsets_size = offsets_size;
525 buffer->async_transaction = is_async;
526 buffer->extra_buffers_size = extra_buffers_size;
529 alloc->free_async_space -= size + sizeof(struct binder_buffer);
530 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
531 "%d: binder_alloc_buf size %zd async free %zd\n",
532 alloc->pid, size, alloc->free_async_space);
533 if (alloc->free_async_space < alloc->buffer_size / 10) {
535 * Start detecting spammers once we have less than 20%
536 * of async space left (which is less than 10% of total
539 debug_low_async_space_locked(alloc, pid);
544 err_alloc_buf_struct_failed:
545 binder_update_page_range(alloc, 0, (void __user *)
546 PAGE_ALIGN((uintptr_t)buffer->user_data),
548 return ERR_PTR(-ENOMEM);
552 * binder_alloc_new_buf() - Allocate a new binder buffer
553 * @alloc: binder_alloc for this proc
554 * @data_size: size of user data buffer
555 * @offsets_size: user specified buffer offset
556 * @extra_buffers_size: size of extra space for meta-data (eg, security context)
557 * @is_async: buffer for async transaction
558 * @pid: pid to attribute allocation to (used for debugging)
560 * Allocate a new buffer given the requested sizes. Returns
561 * the kernel version of the buffer pointer. The size allocated
562 * is the sum of the three given sizes (each rounded up to
563 * pointer-sized boundary)
565 * Return: The allocated buffer or %NULL if error
567 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
570 size_t extra_buffers_size,
574 struct binder_buffer *buffer;
576 mutex_lock(&alloc->mutex);
577 buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
578 extra_buffers_size, is_async, pid);
579 mutex_unlock(&alloc->mutex);
583 static void __user *buffer_start_page(struct binder_buffer *buffer)
585 return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
588 static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
590 return (void __user *)
591 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
594 static void binder_delete_free_buffer(struct binder_alloc *alloc,
595 struct binder_buffer *buffer)
597 struct binder_buffer *prev, *next = NULL;
600 BUG_ON(alloc->buffers.next == &buffer->entry);
601 prev = binder_buffer_prev(buffer);
603 if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
605 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
606 "%d: merge free, buffer %pK share page with %pK\n",
607 alloc->pid, buffer->user_data,
611 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
612 next = binder_buffer_next(buffer);
613 if (buffer_start_page(next) == buffer_start_page(buffer)) {
615 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
616 "%d: merge free, buffer %pK share page with %pK\n",
623 if (PAGE_ALIGNED(buffer->user_data)) {
624 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
625 "%d: merge free, buffer start %pK is page aligned\n",
626 alloc->pid, buffer->user_data);
631 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
632 "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
633 alloc->pid, buffer->user_data,
635 next ? next->user_data : NULL);
636 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
637 buffer_start_page(buffer) + PAGE_SIZE);
639 list_del(&buffer->entry);
643 static void binder_free_buf_locked(struct binder_alloc *alloc,
644 struct binder_buffer *buffer)
646 size_t size, buffer_size;
648 buffer_size = binder_alloc_buffer_size(alloc, buffer);
650 size = ALIGN(buffer->data_size, sizeof(void *)) +
651 ALIGN(buffer->offsets_size, sizeof(void *)) +
652 ALIGN(buffer->extra_buffers_size, sizeof(void *));
654 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
655 "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
656 alloc->pid, buffer, size, buffer_size);
658 BUG_ON(buffer->free);
659 BUG_ON(size > buffer_size);
660 BUG_ON(buffer->transaction != NULL);
661 BUG_ON(buffer->user_data < alloc->buffer);
662 BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
664 if (buffer->async_transaction) {
665 alloc->free_async_space += size + sizeof(struct binder_buffer);
667 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
668 "%d: binder_free_buf size %zd async free %zd\n",
669 alloc->pid, size, alloc->free_async_space);
672 binder_update_page_range(alloc, 0,
673 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
674 (void __user *)(((uintptr_t)
675 buffer->user_data + buffer_size) & PAGE_MASK));
677 rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
679 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
680 struct binder_buffer *next = binder_buffer_next(buffer);
683 rb_erase(&next->rb_node, &alloc->free_buffers);
684 binder_delete_free_buffer(alloc, next);
687 if (alloc->buffers.next != &buffer->entry) {
688 struct binder_buffer *prev = binder_buffer_prev(buffer);
691 binder_delete_free_buffer(alloc, buffer);
692 rb_erase(&prev->rb_node, &alloc->free_buffers);
696 binder_insert_free_buffer(alloc, buffer);
700 * binder_alloc_free_buf() - free a binder buffer
701 * @alloc: binder_alloc for this proc
702 * @buffer: kernel pointer to buffer
704 * Free the buffer allocated via binder_alloc_new_buf()
706 void binder_alloc_free_buf(struct binder_alloc *alloc,
707 struct binder_buffer *buffer)
709 mutex_lock(&alloc->mutex);
710 binder_free_buf_locked(alloc, buffer);
711 mutex_unlock(&alloc->mutex);
715 * binder_alloc_mmap_handler() - map virtual address space for proc
716 * @alloc: alloc structure for this proc
717 * @vma: vma passed to mmap()
719 * Called by binder_mmap() to initialize the space specified in
720 * vma for allocating binder buffers
724 * -EBUSY = address space already mapped
725 * -ENOMEM = failed to map memory to given address space
727 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
728 struct vm_area_struct *vma)
731 const char *failure_string;
732 struct binder_buffer *buffer;
734 mutex_lock(&binder_alloc_mmap_lock);
735 if (alloc->buffer_size) {
737 failure_string = "already mapped";
738 goto err_already_mapped;
740 alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
742 mutex_unlock(&binder_alloc_mmap_lock);
744 alloc->buffer = (void __user *)vma->vm_start;
746 alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
747 sizeof(alloc->pages[0]),
749 if (alloc->pages == NULL) {
751 failure_string = "alloc page array";
752 goto err_alloc_pages_failed;
755 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
758 failure_string = "alloc buffer struct";
759 goto err_alloc_buf_struct_failed;
762 buffer->user_data = alloc->buffer;
763 list_add(&buffer->entry, &alloc->buffers);
765 binder_insert_free_buffer(alloc, buffer);
766 alloc->free_async_space = alloc->buffer_size / 2;
767 binder_alloc_set_vma(alloc, vma);
768 mmgrab(alloc->vma_vm_mm);
772 err_alloc_buf_struct_failed:
775 err_alloc_pages_failed:
776 alloc->buffer = NULL;
777 mutex_lock(&binder_alloc_mmap_lock);
778 alloc->buffer_size = 0;
780 mutex_unlock(&binder_alloc_mmap_lock);
781 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
782 "%s: %d %lx-%lx %s failed %d\n", __func__,
783 alloc->pid, vma->vm_start, vma->vm_end,
784 failure_string, ret);
789 void binder_alloc_deferred_release(struct binder_alloc *alloc)
792 int buffers, page_count;
793 struct binder_buffer *buffer;
796 mutex_lock(&alloc->mutex);
799 while ((n = rb_first(&alloc->allocated_buffers))) {
800 buffer = rb_entry(n, struct binder_buffer, rb_node);
802 /* Transaction should already have been freed */
803 BUG_ON(buffer->transaction);
805 binder_free_buf_locked(alloc, buffer);
809 while (!list_empty(&alloc->buffers)) {
810 buffer = list_first_entry(&alloc->buffers,
811 struct binder_buffer, entry);
812 WARN_ON(!buffer->free);
814 list_del(&buffer->entry);
815 WARN_ON_ONCE(!list_empty(&alloc->buffers));
823 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
824 void __user *page_addr;
827 if (!alloc->pages[i].page_ptr)
830 on_lru = list_lru_del(&binder_alloc_lru,
831 &alloc->pages[i].lru);
832 page_addr = alloc->buffer + i * PAGE_SIZE;
833 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
834 "%s: %d: page %d at %pK %s\n",
835 __func__, alloc->pid, i, page_addr,
836 on_lru ? "on lru" : "active");
837 __free_page(alloc->pages[i].page_ptr);
842 mutex_unlock(&alloc->mutex);
843 if (alloc->vma_vm_mm)
844 mmdrop(alloc->vma_vm_mm);
846 binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
847 "%s: %d buffers %d, pages %d\n",
848 __func__, alloc->pid, buffers, page_count);
851 static void print_binder_buffer(struct seq_file *m, const char *prefix,
852 struct binder_buffer *buffer)
854 seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
855 prefix, buffer->debug_id, buffer->user_data,
856 buffer->data_size, buffer->offsets_size,
857 buffer->extra_buffers_size,
858 buffer->transaction ? "active" : "delivered");
862 * binder_alloc_print_allocated() - print buffer info
863 * @m: seq_file for output via seq_printf()
864 * @alloc: binder_alloc for this proc
866 * Prints information about every buffer associated with
867 * the binder_alloc state to the given seq_file
869 void binder_alloc_print_allocated(struct seq_file *m,
870 struct binder_alloc *alloc)
874 mutex_lock(&alloc->mutex);
875 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
876 print_binder_buffer(m, " buffer",
877 rb_entry(n, struct binder_buffer, rb_node));
878 mutex_unlock(&alloc->mutex);
882 * binder_alloc_print_pages() - print page usage
883 * @m: seq_file for output via seq_printf()
884 * @alloc: binder_alloc for this proc
886 void binder_alloc_print_pages(struct seq_file *m,
887 struct binder_alloc *alloc)
889 struct binder_lru_page *page;
895 mutex_lock(&alloc->mutex);
897 * Make sure the binder_alloc is fully initialized, otherwise we might
898 * read inconsistent state.
900 if (binder_alloc_get_vma(alloc) != NULL) {
901 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
902 page = &alloc->pages[i];
905 else if (list_empty(&page->lru))
911 mutex_unlock(&alloc->mutex);
912 seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
913 seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);
917 * binder_alloc_get_allocated_count() - return count of buffers
918 * @alloc: binder_alloc for this proc
920 * Return: count of allocated buffers
922 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
927 mutex_lock(&alloc->mutex);
928 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
930 mutex_unlock(&alloc->mutex);
936 * binder_alloc_vma_close() - invalidate address space
937 * @alloc: binder_alloc for this proc
939 * Called from binder_vma_close() when releasing address space.
940 * Clears alloc->vma to prevent new incoming transactions from
941 * allocating more buffers.
943 void binder_alloc_vma_close(struct binder_alloc *alloc)
945 binder_alloc_set_vma(alloc, NULL);
949 * binder_alloc_free_page() - shrinker callback to free pages
950 * @item: item to free
951 * @lock: lock protecting the item
952 * @cb_arg: callback argument
954 * Called from list_lru_walk() in binder_shrink_scan() to free
955 * up pages when the system is under memory pressure.
957 enum lru_status binder_alloc_free_page(struct list_head *item,
958 struct list_lru_one *lru,
963 struct mm_struct *mm = NULL;
964 struct binder_lru_page *page = container_of(item,
965 struct binder_lru_page,
967 struct binder_alloc *alloc;
970 struct vm_area_struct *vma;
973 if (!mutex_trylock(&alloc->mutex))
974 goto err_get_alloc_mutex_failed;
977 goto err_page_already_freed;
979 index = page - alloc->pages;
980 page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
982 mm = alloc->vma_vm_mm;
983 if (!mmget_not_zero(mm))
985 if (!mmap_read_trylock(mm))
986 goto err_mmap_read_lock_failed;
987 vma = binder_alloc_get_vma(alloc);
989 list_lru_isolate(lru, item);
993 trace_binder_unmap_user_start(alloc, index);
995 zap_page_range(vma, page_addr, PAGE_SIZE);
997 trace_binder_unmap_user_end(alloc, index);
999 mmap_read_unlock(mm);
1002 trace_binder_unmap_kernel_start(alloc, index);
1004 __free_page(page->page_ptr);
1005 page->page_ptr = NULL;
1007 trace_binder_unmap_kernel_end(alloc, index);
1010 mutex_unlock(&alloc->mutex);
1011 return LRU_REMOVED_RETRY;
1013 err_mmap_read_lock_failed:
1016 err_page_already_freed:
1017 mutex_unlock(&alloc->mutex);
1018 err_get_alloc_mutex_failed:
1022 static unsigned long
1023 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
1025 unsigned long ret = list_lru_count(&binder_alloc_lru);
1029 static unsigned long
1030 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1034 ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
1035 NULL, sc->nr_to_scan);
1039 static struct shrinker binder_shrinker = {
1040 .count_objects = binder_shrink_count,
1041 .scan_objects = binder_shrink_scan,
1042 .seeks = DEFAULT_SEEKS,
1046 * binder_alloc_init() - called by binder_open() for per-proc initialization
1047 * @alloc: binder_alloc for this proc
1049 * Called from binder_open() to initialize binder_alloc fields for
1052 void binder_alloc_init(struct binder_alloc *alloc)
1054 alloc->pid = current->group_leader->pid;
1055 mutex_init(&alloc->mutex);
1056 INIT_LIST_HEAD(&alloc->buffers);
1059 int binder_alloc_shrinker_init(void)
1061 int ret = list_lru_init(&binder_alloc_lru);
1064 ret = register_shrinker(&binder_shrinker);
1066 list_lru_destroy(&binder_alloc_lru);
1072 * check_buffer() - verify that buffer/offset is safe to access
1073 * @alloc: binder_alloc for this proc
1074 * @buffer: binder buffer to be accessed
1075 * @offset: offset into @buffer data
1076 * @bytes: bytes to access from offset
1078 * Check that the @offset/@bytes are within the size of the given
1079 * @buffer and that the buffer is currently active and not freeable.
1080 * Offsets must also be multiples of sizeof(u32). The kernel is
1081 * allowed to touch the buffer in two cases:
1083 * 1) when the buffer is being created:
1084 * (buffer->free == 0 && buffer->allow_user_free == 0)
1085 * 2) when the buffer is being torn down:
1086 * (buffer->free == 0 && buffer->transaction == NULL).
1088 * Return: true if the buffer is safe to access
1090 static inline bool check_buffer(struct binder_alloc *alloc,
1091 struct binder_buffer *buffer,
1092 binder_size_t offset, size_t bytes)
1094 size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1096 return buffer_size >= bytes &&
1097 offset <= buffer_size - bytes &&
1098 IS_ALIGNED(offset, sizeof(u32)) &&
1100 (!buffer->allow_user_free || !buffer->transaction);
1104 * binder_alloc_get_page() - get kernel pointer for given buffer offset
1105 * @alloc: binder_alloc for this proc
1106 * @buffer: binder buffer to be accessed
1107 * @buffer_offset: offset into @buffer data
1108 * @pgoffp: address to copy final page offset to
1110 * Lookup the struct page corresponding to the address
1111 * at @buffer_offset into @buffer->user_data. If @pgoffp is not
1112 * NULL, the byte-offset into the page is written there.
1114 * The caller is responsible to ensure that the offset points
1115 * to a valid address within the @buffer and that @buffer is
1116 * not freeable by the user. Since it can't be freed, we are
1117 * guaranteed that the corresponding elements of @alloc->pages[]
1120 * Return: struct page
1122 static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1123 struct binder_buffer *buffer,
1124 binder_size_t buffer_offset,
1127 binder_size_t buffer_space_offset = buffer_offset +
1128 (buffer->user_data - alloc->buffer);
1129 pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
1130 size_t index = buffer_space_offset >> PAGE_SHIFT;
1131 struct binder_lru_page *lru_page;
1133 lru_page = &alloc->pages[index];
1135 return lru_page->page_ptr;
1139 * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1140 * @alloc: binder_alloc for this proc
1141 * @buffer: binder buffer to be accessed
1142 * @buffer_offset: offset into @buffer data
1143 * @from: userspace pointer to source buffer
1144 * @bytes: bytes to copy
1146 * Copy bytes from source userspace to target buffer.
1148 * Return: bytes remaining to be copied
1151 binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1152 struct binder_buffer *buffer,
1153 binder_size_t buffer_offset,
1154 const void __user *from,
1157 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1167 page = binder_alloc_get_page(alloc, buffer,
1168 buffer_offset, &pgoff);
1169 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1170 kptr = kmap(page) + pgoff;
1171 ret = copy_from_user(kptr, from, size);
1174 return bytes - size + ret;
1177 buffer_offset += size;
1182 static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1184 struct binder_buffer *buffer,
1185 binder_size_t buffer_offset,
1189 /* All copies must be 32-bit aligned and 32-bit size */
1190 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1200 page = binder_alloc_get_page(alloc, buffer,
1201 buffer_offset, &pgoff);
1202 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1203 base_ptr = kmap_atomic(page);
1204 tmpptr = base_ptr + pgoff;
1206 memcpy(tmpptr, ptr, size);
1208 memcpy(ptr, tmpptr, size);
1210 * kunmap_atomic() takes care of flushing the cache
1211 * if this device has VIVT cache arch
1213 kunmap_atomic(base_ptr);
1217 buffer_offset += size;
1222 int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1223 struct binder_buffer *buffer,
1224 binder_size_t buffer_offset,
1228 return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1232 int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1234 struct binder_buffer *buffer,
1235 binder_size_t buffer_offset,
1238 return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,