3 * Android IPC Subsystem
5 * Copyright (C) 2007-2017 Google, Inc.
7 * This software is licensed under the terms of the GNU General Public
8 * License version 2, as published by the Free Software Foundation, and
9 * may be copied, distributed, and modified under those terms.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 #include <linux/list.h>
21 #include <linux/sched/mm.h>
22 #include <linux/module.h>
23 #include <linux/rtmutex.h>
24 #include <linux/rbtree.h>
25 #include <linux/seq_file.h>
26 #include <linux/vmalloc.h>
27 #include <linux/slab.h>
28 #include <linux/sched.h>
29 #include <linux/list_lru.h>
30 #include <linux/ratelimit.h>
31 #include <asm/cacheflush.h>
32 #include <linux/uaccess.h>
33 #include <linux/highmem.h>
34 #include "binder_alloc.h"
35 #include "binder_trace.h"
37 struct list_lru binder_alloc_lru;
39 static DEFINE_MUTEX(binder_alloc_mmap_lock);
42 BINDER_DEBUG_USER_ERROR = 1U << 0,
43 BINDER_DEBUG_OPEN_CLOSE = 1U << 1,
44 BINDER_DEBUG_BUFFER_ALLOC = 1U << 2,
45 BINDER_DEBUG_BUFFER_ALLOC_ASYNC = 1U << 3,
47 static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
49 module_param_named(debug_mask, binder_alloc_debug_mask,
52 #define binder_alloc_debug(mask, x...) \
54 if (binder_alloc_debug_mask & mask) \
55 pr_info_ratelimited(x); \
58 static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
60 return list_entry(buffer->entry.next, struct binder_buffer, entry);
63 static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
65 return list_entry(buffer->entry.prev, struct binder_buffer, entry);
68 static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
69 struct binder_buffer *buffer)
71 if (list_is_last(&buffer->entry, &alloc->buffers))
72 return alloc->buffer + alloc->buffer_size - buffer->user_data;
73 return binder_buffer_next(buffer)->user_data - buffer->user_data;
76 static void binder_insert_free_buffer(struct binder_alloc *alloc,
77 struct binder_buffer *new_buffer)
79 struct rb_node **p = &alloc->free_buffers.rb_node;
80 struct rb_node *parent = NULL;
81 struct binder_buffer *buffer;
83 size_t new_buffer_size;
85 BUG_ON(!new_buffer->free);
87 new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
89 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
90 "%d: add free buffer, size %zd, at %pK\n",
91 alloc->pid, new_buffer_size, new_buffer);
95 buffer = rb_entry(parent, struct binder_buffer, rb_node);
96 BUG_ON(!buffer->free);
98 buffer_size = binder_alloc_buffer_size(alloc, buffer);
100 if (new_buffer_size < buffer_size)
101 p = &parent->rb_left;
103 p = &parent->rb_right;
105 rb_link_node(&new_buffer->rb_node, parent, p);
106 rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
109 static void binder_insert_allocated_buffer_locked(
110 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
112 struct rb_node **p = &alloc->allocated_buffers.rb_node;
113 struct rb_node *parent = NULL;
114 struct binder_buffer *buffer;
116 BUG_ON(new_buffer->free);
120 buffer = rb_entry(parent, struct binder_buffer, rb_node);
121 BUG_ON(buffer->free);
123 if (new_buffer->user_data < buffer->user_data)
124 p = &parent->rb_left;
125 else if (new_buffer->user_data > buffer->user_data)
126 p = &parent->rb_right;
130 rb_link_node(&new_buffer->rb_node, parent, p);
131 rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
134 static struct binder_buffer *binder_alloc_prepare_to_free_locked(
135 struct binder_alloc *alloc,
138 struct rb_node *n = alloc->allocated_buffers.rb_node;
139 struct binder_buffer *buffer;
142 uptr = (void __user *)user_ptr;
145 buffer = rb_entry(n, struct binder_buffer, rb_node);
146 BUG_ON(buffer->free);
148 if (uptr < buffer->user_data)
150 else if (uptr > buffer->user_data)
154 * Guard against user threads attempting to
155 * free the buffer when in use by kernel or
156 * after it's already been freed.
158 if (!buffer->allow_user_free)
159 return ERR_PTR(-EPERM);
160 buffer->allow_user_free = 0;
168 * binder_alloc_buffer_lookup() - get buffer given user ptr
169 * @alloc: binder_alloc for this proc
170 * @user_ptr: User pointer to buffer data
172 * Validate userspace pointer to buffer data and return buffer corresponding to
173 * that user pointer. Search the rb tree for buffer that matches user data
176 * Return: Pointer to buffer or NULL
178 struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
181 struct binder_buffer *buffer;
183 mutex_lock(&alloc->mutex);
184 buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
185 mutex_unlock(&alloc->mutex);
189 static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
190 void __user *start, void __user *end)
192 void __user *page_addr;
193 unsigned long user_page_addr;
194 struct binder_lru_page *page;
195 struct vm_area_struct *vma = NULL;
196 struct mm_struct *mm = NULL;
197 bool need_mm = false;
199 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
200 "%d: %s pages %pK-%pK\n", alloc->pid,
201 allocate ? "allocate" : "free", start, end);
206 trace_binder_update_page_range(alloc, allocate, start, end);
211 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
212 page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
213 if (!page->page_ptr) {
219 if (need_mm && mmget_not_zero(alloc->vma_vm_mm))
220 mm = alloc->vma_vm_mm;
223 down_read(&mm->mmap_sem);
227 if (!vma && need_mm) {
228 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
229 "%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
234 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
239 index = (page_addr - alloc->buffer) / PAGE_SIZE;
240 page = &alloc->pages[index];
242 if (page->page_ptr) {
243 trace_binder_alloc_lru_start(alloc, index);
245 on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
248 trace_binder_alloc_lru_end(alloc, index);
253 goto err_page_ptr_cleared;
255 trace_binder_alloc_page_start(alloc, index);
256 page->page_ptr = alloc_page(GFP_KERNEL |
259 if (!page->page_ptr) {
260 pr_err("%d: binder_alloc_buf failed for page at %pK\n",
261 alloc->pid, page_addr);
262 goto err_alloc_page_failed;
265 INIT_LIST_HEAD(&page->lru);
267 user_page_addr = (uintptr_t)page_addr;
268 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
270 pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
271 alloc->pid, user_page_addr);
272 goto err_vm_insert_page_failed;
275 if (index + 1 > alloc->pages_high)
276 alloc->pages_high = index + 1;
278 trace_binder_alloc_page_end(alloc, index);
279 /* vm_insert_page does not seem to increment the refcount */
282 up_read(&mm->mmap_sem);
288 for (page_addr = end - PAGE_SIZE; page_addr >= start;
289 page_addr -= PAGE_SIZE) {
293 index = (page_addr - alloc->buffer) / PAGE_SIZE;
294 page = &alloc->pages[index];
296 trace_binder_free_lru_start(alloc, index);
298 ret = list_lru_add(&binder_alloc_lru, &page->lru);
301 trace_binder_free_lru_end(alloc, index);
304 err_vm_insert_page_failed:
305 __free_page(page->page_ptr);
306 page->page_ptr = NULL;
307 err_alloc_page_failed:
308 err_page_ptr_cleared:
313 up_read(&mm->mmap_sem);
316 return vma ? -ENOMEM : -ESRCH;
320 static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
321 struct vm_area_struct *vma)
324 alloc->vma_vm_mm = vma->vm_mm;
326 * If we see alloc->vma is not NULL, buffer data structures set up
327 * completely. Look at smp_rmb side binder_alloc_get_vma.
328 * We also want to guarantee new alloc->vma_vm_mm is always visible
329 * if alloc->vma is set.
335 static inline struct vm_area_struct *binder_alloc_get_vma(
336 struct binder_alloc *alloc)
338 struct vm_area_struct *vma = NULL;
341 /* Look at description in binder_alloc_set_vma */
348 static struct binder_buffer *binder_alloc_new_buf_locked(
349 struct binder_alloc *alloc,
352 size_t extra_buffers_size,
355 struct rb_node *n = alloc->free_buffers.rb_node;
356 struct binder_buffer *buffer;
358 struct rb_node *best_fit = NULL;
359 void __user *has_page_addr;
360 void __user *end_page_addr;
361 size_t size, data_offsets_size;
364 if (!binder_alloc_get_vma(alloc)) {
365 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
366 "%d: binder_alloc_buf, no vma\n",
368 return ERR_PTR(-ESRCH);
371 data_offsets_size = ALIGN(data_size, sizeof(void *)) +
372 ALIGN(offsets_size, sizeof(void *));
374 if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
375 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
376 "%d: got transaction with invalid size %zd-%zd\n",
377 alloc->pid, data_size, offsets_size);
378 return ERR_PTR(-EINVAL);
380 size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
381 if (size < data_offsets_size || size < extra_buffers_size) {
382 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
383 "%d: got transaction with invalid extra_buffers_size %zd\n",
384 alloc->pid, extra_buffers_size);
385 return ERR_PTR(-EINVAL);
388 alloc->free_async_space < size + sizeof(struct binder_buffer)) {
389 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
390 "%d: binder_alloc_buf size %zd failed, no async space left\n",
392 return ERR_PTR(-ENOSPC);
395 /* Pad 0-size buffers so they get assigned unique addresses */
396 size = max(size, sizeof(void *));
399 buffer = rb_entry(n, struct binder_buffer, rb_node);
400 BUG_ON(!buffer->free);
401 buffer_size = binder_alloc_buffer_size(alloc, buffer);
403 if (size < buffer_size) {
406 } else if (size > buffer_size)
413 if (best_fit == NULL) {
414 size_t allocated_buffers = 0;
415 size_t largest_alloc_size = 0;
416 size_t total_alloc_size = 0;
417 size_t free_buffers = 0;
418 size_t largest_free_size = 0;
419 size_t total_free_size = 0;
421 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
423 buffer = rb_entry(n, struct binder_buffer, rb_node);
424 buffer_size = binder_alloc_buffer_size(alloc, buffer);
426 total_alloc_size += buffer_size;
427 if (buffer_size > largest_alloc_size)
428 largest_alloc_size = buffer_size;
430 for (n = rb_first(&alloc->free_buffers); n != NULL;
432 buffer = rb_entry(n, struct binder_buffer, rb_node);
433 buffer_size = binder_alloc_buffer_size(alloc, buffer);
435 total_free_size += buffer_size;
436 if (buffer_size > largest_free_size)
437 largest_free_size = buffer_size;
439 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
440 "%d: binder_alloc_buf size %zd failed, no address space\n",
442 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
443 "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
444 total_alloc_size, allocated_buffers,
445 largest_alloc_size, total_free_size,
446 free_buffers, largest_free_size);
447 return ERR_PTR(-ENOSPC);
450 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
451 buffer_size = binder_alloc_buffer_size(alloc, buffer);
454 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
455 "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
456 alloc->pid, size, buffer, buffer_size);
458 has_page_addr = (void __user *)
459 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
460 WARN_ON(n && buffer_size != size);
462 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
463 if (end_page_addr > has_page_addr)
464 end_page_addr = has_page_addr;
465 ret = binder_update_page_range(alloc, 1, (void __user *)
466 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
470 if (buffer_size != size) {
471 struct binder_buffer *new_buffer;
473 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
475 pr_err("%s: %d failed to alloc new buffer struct\n",
476 __func__, alloc->pid);
477 goto err_alloc_buf_struct_failed;
479 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
480 list_add(&new_buffer->entry, &buffer->entry);
481 new_buffer->free = 1;
482 binder_insert_free_buffer(alloc, new_buffer);
485 rb_erase(best_fit, &alloc->free_buffers);
487 buffer->allow_user_free = 0;
488 binder_insert_allocated_buffer_locked(alloc, buffer);
489 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
490 "%d: binder_alloc_buf size %zd got %pK\n",
491 alloc->pid, size, buffer);
492 buffer->data_size = data_size;
493 buffer->offsets_size = offsets_size;
494 buffer->async_transaction = is_async;
495 buffer->extra_buffers_size = extra_buffers_size;
497 alloc->free_async_space -= size + sizeof(struct binder_buffer);
498 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
499 "%d: binder_alloc_buf size %zd async free %zd\n",
500 alloc->pid, size, alloc->free_async_space);
504 err_alloc_buf_struct_failed:
505 binder_update_page_range(alloc, 0, (void __user *)
506 PAGE_ALIGN((uintptr_t)buffer->user_data),
508 return ERR_PTR(-ENOMEM);
512 * binder_alloc_new_buf() - Allocate a new binder buffer
513 * @alloc: binder_alloc for this proc
514 * @data_size: size of user data buffer
515 * @offsets_size: user specified buffer offset
516 * @extra_buffers_size: size of extra space for meta-data (eg, security context)
517 * @is_async: buffer for async transaction
519 * Allocate a new buffer given the requested sizes. Returns
520 * the kernel version of the buffer pointer. The size allocated
521 * is the sum of the three given sizes (each rounded up to
522 * pointer-sized boundary)
524 * Return: The allocated buffer or %NULL if error
526 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
529 size_t extra_buffers_size,
532 struct binder_buffer *buffer;
534 mutex_lock(&alloc->mutex);
535 buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
536 extra_buffers_size, is_async);
537 mutex_unlock(&alloc->mutex);
541 static void __user *buffer_start_page(struct binder_buffer *buffer)
543 return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
546 static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
548 return (void __user *)
549 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
552 static void binder_delete_free_buffer(struct binder_alloc *alloc,
553 struct binder_buffer *buffer)
555 struct binder_buffer *prev, *next = NULL;
557 BUG_ON(alloc->buffers.next == &buffer->entry);
558 prev = binder_buffer_prev(buffer);
560 if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
562 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
563 "%d: merge free, buffer %pK share page with %pK\n",
564 alloc->pid, buffer->user_data,
568 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
569 next = binder_buffer_next(buffer);
570 if (buffer_start_page(next) == buffer_start_page(buffer)) {
572 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
573 "%d: merge free, buffer %pK share page with %pK\n",
580 if (PAGE_ALIGNED(buffer->user_data)) {
581 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
582 "%d: merge free, buffer start %pK is page aligned\n",
583 alloc->pid, buffer->user_data);
588 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
589 "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
590 alloc->pid, buffer->user_data,
592 next ? next->user_data : NULL);
593 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
594 buffer_start_page(buffer) + PAGE_SIZE);
596 list_del(&buffer->entry);
600 static void binder_free_buf_locked(struct binder_alloc *alloc,
601 struct binder_buffer *buffer)
603 size_t size, buffer_size;
605 buffer_size = binder_alloc_buffer_size(alloc, buffer);
607 size = ALIGN(buffer->data_size, sizeof(void *)) +
608 ALIGN(buffer->offsets_size, sizeof(void *)) +
609 ALIGN(buffer->extra_buffers_size, sizeof(void *));
611 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
612 "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
613 alloc->pid, buffer, size, buffer_size);
615 BUG_ON(buffer->free);
616 BUG_ON(size > buffer_size);
617 BUG_ON(buffer->transaction != NULL);
618 BUG_ON(buffer->user_data < alloc->buffer);
619 BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
621 if (buffer->async_transaction) {
622 alloc->free_async_space += size + sizeof(struct binder_buffer);
624 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
625 "%d: binder_free_buf size %zd async free %zd\n",
626 alloc->pid, size, alloc->free_async_space);
629 binder_update_page_range(alloc, 0,
630 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
631 (void __user *)(((uintptr_t)
632 buffer->user_data + buffer_size) & PAGE_MASK));
634 rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
636 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
637 struct binder_buffer *next = binder_buffer_next(buffer);
640 rb_erase(&next->rb_node, &alloc->free_buffers);
641 binder_delete_free_buffer(alloc, next);
644 if (alloc->buffers.next != &buffer->entry) {
645 struct binder_buffer *prev = binder_buffer_prev(buffer);
648 binder_delete_free_buffer(alloc, buffer);
649 rb_erase(&prev->rb_node, &alloc->free_buffers);
653 binder_insert_free_buffer(alloc, buffer);
657 * binder_alloc_free_buf() - free a binder buffer
658 * @alloc: binder_alloc for this proc
659 * @buffer: kernel pointer to buffer
661 * Free the buffer allocated via binder_alloc_new_buffer()
663 void binder_alloc_free_buf(struct binder_alloc *alloc,
664 struct binder_buffer *buffer)
666 mutex_lock(&alloc->mutex);
667 binder_free_buf_locked(alloc, buffer);
668 mutex_unlock(&alloc->mutex);
672 * binder_alloc_mmap_handler() - map virtual address space for proc
673 * @alloc: alloc structure for this proc
674 * @vma: vma passed to mmap()
676 * Called by binder_mmap() to initialize the space specified in
677 * vma for allocating binder buffers
681 * -EBUSY = address space already mapped
682 * -ENOMEM = failed to map memory to given address space
684 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
685 struct vm_area_struct *vma)
688 const char *failure_string;
689 struct binder_buffer *buffer;
691 mutex_lock(&binder_alloc_mmap_lock);
694 failure_string = "already mapped";
695 goto err_already_mapped;
698 alloc->buffer = (void __user *)vma->vm_start;
699 mutex_unlock(&binder_alloc_mmap_lock);
701 alloc->pages = kcalloc((vma->vm_end - vma->vm_start) / PAGE_SIZE,
702 sizeof(alloc->pages[0]),
704 if (alloc->pages == NULL) {
706 failure_string = "alloc page array";
707 goto err_alloc_pages_failed;
709 alloc->buffer_size = vma->vm_end - vma->vm_start;
711 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
714 failure_string = "alloc buffer struct";
715 goto err_alloc_buf_struct_failed;
718 buffer->user_data = alloc->buffer;
719 list_add(&buffer->entry, &alloc->buffers);
721 binder_insert_free_buffer(alloc, buffer);
722 alloc->free_async_space = alloc->buffer_size / 2;
723 binder_alloc_set_vma(alloc, vma);
724 mmgrab(alloc->vma_vm_mm);
728 err_alloc_buf_struct_failed:
731 err_alloc_pages_failed:
732 mutex_lock(&binder_alloc_mmap_lock);
733 alloc->buffer = NULL;
735 mutex_unlock(&binder_alloc_mmap_lock);
736 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
737 "%s: %d %lx-%lx %s failed %d\n", __func__,
738 alloc->pid, vma->vm_start, vma->vm_end,
739 failure_string, ret);
744 void binder_alloc_deferred_release(struct binder_alloc *alloc)
747 int buffers, page_count;
748 struct binder_buffer *buffer;
751 mutex_lock(&alloc->mutex);
754 while ((n = rb_first(&alloc->allocated_buffers))) {
755 buffer = rb_entry(n, struct binder_buffer, rb_node);
757 /* Transaction should already have been freed */
758 BUG_ON(buffer->transaction);
760 binder_free_buf_locked(alloc, buffer);
764 while (!list_empty(&alloc->buffers)) {
765 buffer = list_first_entry(&alloc->buffers,
766 struct binder_buffer, entry);
767 WARN_ON(!buffer->free);
769 list_del(&buffer->entry);
770 WARN_ON_ONCE(!list_empty(&alloc->buffers));
778 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
779 void __user *page_addr;
782 if (!alloc->pages[i].page_ptr)
785 on_lru = list_lru_del(&binder_alloc_lru,
786 &alloc->pages[i].lru);
787 page_addr = alloc->buffer + i * PAGE_SIZE;
788 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
789 "%s: %d: page %d at %pK %s\n",
790 __func__, alloc->pid, i, page_addr,
791 on_lru ? "on lru" : "active");
792 __free_page(alloc->pages[i].page_ptr);
797 mutex_unlock(&alloc->mutex);
798 if (alloc->vma_vm_mm)
799 mmdrop(alloc->vma_vm_mm);
801 binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
802 "%s: %d buffers %d, pages %d\n",
803 __func__, alloc->pid, buffers, page_count);
806 static void print_binder_buffer(struct seq_file *m, const char *prefix,
807 struct binder_buffer *buffer)
809 seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
810 prefix, buffer->debug_id, buffer->user_data,
811 buffer->data_size, buffer->offsets_size,
812 buffer->extra_buffers_size,
813 buffer->transaction ? "active" : "delivered");
817 * binder_alloc_print_allocated() - print buffer info
818 * @m: seq_file for output via seq_printf()
819 * @alloc: binder_alloc for this proc
821 * Prints information about every buffer associated with
822 * the binder_alloc state to the given seq_file
824 void binder_alloc_print_allocated(struct seq_file *m,
825 struct binder_alloc *alloc)
829 mutex_lock(&alloc->mutex);
830 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
831 print_binder_buffer(m, " buffer",
832 rb_entry(n, struct binder_buffer, rb_node));
833 mutex_unlock(&alloc->mutex);
837 * binder_alloc_print_pages() - print page usage
838 * @m: seq_file for output via seq_printf()
839 * @alloc: binder_alloc for this proc
841 void binder_alloc_print_pages(struct seq_file *m,
842 struct binder_alloc *alloc)
844 struct binder_lru_page *page;
850 mutex_lock(&alloc->mutex);
851 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
852 page = &alloc->pages[i];
855 else if (list_empty(&page->lru))
860 mutex_unlock(&alloc->mutex);
861 seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
862 seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);
866 * binder_alloc_get_allocated_count() - return count of buffers
867 * @alloc: binder_alloc for this proc
869 * Return: count of allocated buffers
871 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
876 mutex_lock(&alloc->mutex);
877 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
879 mutex_unlock(&alloc->mutex);
885 * binder_alloc_vma_close() - invalidate address space
886 * @alloc: binder_alloc for this proc
888 * Called from binder_vma_close() when releasing address space.
889 * Clears alloc->vma to prevent new incoming transactions from
890 * allocating more buffers.
892 void binder_alloc_vma_close(struct binder_alloc *alloc)
894 binder_alloc_set_vma(alloc, NULL);
898 * binder_alloc_free_page() - shrinker callback to free pages
899 * @item: item to free
900 * @lock: lock protecting the item
901 * @cb_arg: callback argument
903 * Called from list_lru_walk() in binder_shrink_scan() to free
904 * up pages when the system is under memory pressure.
906 enum lru_status binder_alloc_free_page(struct list_head *item,
907 struct list_lru_one *lru,
912 struct mm_struct *mm = NULL;
913 struct binder_lru_page *page = container_of(item,
914 struct binder_lru_page,
916 struct binder_alloc *alloc;
919 struct vm_area_struct *vma;
922 if (!mutex_trylock(&alloc->mutex))
923 goto err_get_alloc_mutex_failed;
926 goto err_page_already_freed;
928 index = page - alloc->pages;
929 page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
931 mm = alloc->vma_vm_mm;
932 if (!mmget_not_zero(mm))
934 if (!down_read_trylock(&mm->mmap_sem))
935 goto err_down_read_mmap_sem_failed;
936 vma = binder_alloc_get_vma(alloc);
938 list_lru_isolate(lru, item);
942 trace_binder_unmap_user_start(alloc, index);
944 zap_page_range(vma, page_addr, PAGE_SIZE);
946 trace_binder_unmap_user_end(alloc, index);
948 up_read(&mm->mmap_sem);
951 trace_binder_unmap_kernel_start(alloc, index);
953 __free_page(page->page_ptr);
954 page->page_ptr = NULL;
956 trace_binder_unmap_kernel_end(alloc, index);
959 mutex_unlock(&alloc->mutex);
960 return LRU_REMOVED_RETRY;
962 err_down_read_mmap_sem_failed:
965 err_page_already_freed:
966 mutex_unlock(&alloc->mutex);
967 err_get_alloc_mutex_failed:
972 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
974 unsigned long ret = list_lru_count(&binder_alloc_lru);
979 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
983 ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
984 NULL, sc->nr_to_scan);
988 static struct shrinker binder_shrinker = {
989 .count_objects = binder_shrink_count,
990 .scan_objects = binder_shrink_scan,
991 .seeks = DEFAULT_SEEKS,
995 * binder_alloc_init() - called by binder_open() for per-proc initialization
996 * @alloc: binder_alloc for this proc
998 * Called from binder_open() to initialize binder_alloc fields for
1001 void binder_alloc_init(struct binder_alloc *alloc)
1003 alloc->pid = current->group_leader->pid;
1004 mutex_init(&alloc->mutex);
1005 INIT_LIST_HEAD(&alloc->buffers);
1008 int binder_alloc_shrinker_init(void)
1010 int ret = list_lru_init(&binder_alloc_lru);
1013 ret = register_shrinker(&binder_shrinker);
1015 list_lru_destroy(&binder_alloc_lru);
1021 * check_buffer() - verify that buffer/offset is safe to access
1022 * @alloc: binder_alloc for this proc
1023 * @buffer: binder buffer to be accessed
1024 * @offset: offset into @buffer data
1025 * @bytes: bytes to access from offset
1027 * Check that the @offset/@bytes are within the size of the given
1028 * @buffer and that the buffer is currently active and not freeable.
1029 * Offsets must also be multiples of sizeof(u32). The kernel is
1030 * allowed to touch the buffer in two cases:
1032 * 1) when the buffer is being created:
1033 * (buffer->free == 0 && buffer->allow_user_free == 0)
1034 * 2) when the buffer is being torn down:
1035 * (buffer->free == 0 && buffer->transaction == NULL).
1037 * Return: true if the buffer is safe to access
1039 static inline bool check_buffer(struct binder_alloc *alloc,
1040 struct binder_buffer *buffer,
1041 binder_size_t offset, size_t bytes)
1043 size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1045 return buffer_size >= bytes &&
1046 offset <= buffer_size - bytes &&
1047 IS_ALIGNED(offset, sizeof(u32)) &&
1049 (!buffer->allow_user_free || !buffer->transaction);
1053 * binder_alloc_get_page() - get kernel pointer for given buffer offset
1054 * @alloc: binder_alloc for this proc
1055 * @buffer: binder buffer to be accessed
1056 * @buffer_offset: offset into @buffer data
1057 * @pgoffp: address to copy final page offset to
1059 * Lookup the struct page corresponding to the address
1060 * at @buffer_offset into @buffer->user_data. If @pgoffp is not
1061 * NULL, the byte-offset into the page is written there.
1063 * The caller is responsible to ensure that the offset points
1064 * to a valid address within the @buffer and that @buffer is
1065 * not freeable by the user. Since it can't be freed, we are
1066 * guaranteed that the corresponding elements of @alloc->pages[]
1069 * Return: struct page
1071 static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1072 struct binder_buffer *buffer,
1073 binder_size_t buffer_offset,
1076 binder_size_t buffer_space_offset = buffer_offset +
1077 (buffer->user_data - alloc->buffer);
1078 pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
1079 size_t index = buffer_space_offset >> PAGE_SHIFT;
1080 struct binder_lru_page *lru_page;
1082 lru_page = &alloc->pages[index];
1084 return lru_page->page_ptr;
1088 * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1089 * @alloc: binder_alloc for this proc
1090 * @buffer: binder buffer to be accessed
1091 * @buffer_offset: offset into @buffer data
1092 * @from: userspace pointer to source buffer
1093 * @bytes: bytes to copy
1095 * Copy bytes from source userspace to target buffer.
1097 * Return: bytes remaining to be copied
1100 binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1101 struct binder_buffer *buffer,
1102 binder_size_t buffer_offset,
1103 const void __user *from,
1106 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1116 page = binder_alloc_get_page(alloc, buffer,
1117 buffer_offset, &pgoff);
1118 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1119 kptr = kmap(page) + pgoff;
1120 ret = copy_from_user(kptr, from, size);
1123 return bytes - size + ret;
1126 buffer_offset += size;
1131 static void binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1133 struct binder_buffer *buffer,
1134 binder_size_t buffer_offset,
1138 /* All copies must be 32-bit aligned and 32-bit size */
1139 BUG_ON(!check_buffer(alloc, buffer, buffer_offset, bytes));
1148 page = binder_alloc_get_page(alloc, buffer,
1149 buffer_offset, &pgoff);
1150 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1151 base_ptr = kmap_atomic(page);
1152 tmpptr = base_ptr + pgoff;
1154 memcpy(tmpptr, ptr, size);
1156 memcpy(ptr, tmpptr, size);
1158 * kunmap_atomic() takes care of flushing the cache
1159 * if this device has VIVT cache arch
1161 kunmap_atomic(base_ptr);
1165 buffer_offset += size;
1169 void binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1170 struct binder_buffer *buffer,
1171 binder_size_t buffer_offset,
1175 binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1179 void binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1181 struct binder_buffer *buffer,
1182 binder_size_t buffer_offset,
1185 binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,