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1/* binder_alloc.c
2 *
3 * Android IPC Subsystem
4 *
5 * Copyright (C) 2007-2017 Google, Inc.
6 *
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.
10 *
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.
15 *
16 */
17
18#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19
20#include <asm/cacheflush.h>
21#include <linux/list.h>
22#include <linux/sched/mm.h>
23#include <linux/module.h>
24#include <linux/rtmutex.h>
25#include <linux/rbtree.h>
26#include <linux/seq_file.h>
27#include <linux/vmalloc.h>
28#include <linux/slab.h>
29#include <linux/sched.h>
30#include <linux/list_lru.h>
31#include "binder_alloc.h"
32#include "binder_trace.h"
33
34struct list_lru binder_alloc_lru;
35
36static DEFINE_MUTEX(binder_alloc_mmap_lock);
37
38enum {
39 BINDER_DEBUG_OPEN_CLOSE = 1U << 1,
40 BINDER_DEBUG_BUFFER_ALLOC = 1U << 2,
41 BINDER_DEBUG_BUFFER_ALLOC_ASYNC = 1U << 3,
42};
43static uint32_t binder_alloc_debug_mask;
44
45module_param_named(debug_mask, binder_alloc_debug_mask,
46 uint, 0644);
47
48#define binder_alloc_debug(mask, x...) \
49 do { \
50 if (binder_alloc_debug_mask & mask) \
51 pr_info(x); \
52 } while (0)
53
54static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
55{
56 return list_entry(buffer->entry.next, struct binder_buffer, entry);
57}
58
59static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
60{
61 return list_entry(buffer->entry.prev, struct binder_buffer, entry);
62}
63
64static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
65 struct binder_buffer *buffer)
66{
67 if (list_is_last(&buffer->entry, &alloc->buffers))
68 return (u8 *)alloc->buffer +
69 alloc->buffer_size - (u8 *)buffer->data;
70 return (u8 *)binder_buffer_next(buffer)->data - (u8 *)buffer->data;
71}
72
73static void binder_insert_free_buffer(struct binder_alloc *alloc,
74 struct binder_buffer *new_buffer)
75{
76 struct rb_node **p = &alloc->free_buffers.rb_node;
77 struct rb_node *parent = NULL;
78 struct binder_buffer *buffer;
79 size_t buffer_size;
80 size_t new_buffer_size;
81
82 BUG_ON(!new_buffer->free);
83
84 new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
85
86 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
87 "%d: add free buffer, size %zd, at %pK\n",
88 alloc->pid, new_buffer_size, new_buffer);
89
90 while (*p) {
91 parent = *p;
92 buffer = rb_entry(parent, struct binder_buffer, rb_node);
93 BUG_ON(!buffer->free);
94
95 buffer_size = binder_alloc_buffer_size(alloc, buffer);
96
97 if (new_buffer_size < buffer_size)
98 p = &parent->rb_left;
99 else
100 p = &parent->rb_right;
101 }
102 rb_link_node(&new_buffer->rb_node, parent, p);
103 rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
104}
105
106static void binder_insert_allocated_buffer_locked(
107 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
108{
109 struct rb_node **p = &alloc->allocated_buffers.rb_node;
110 struct rb_node *parent = NULL;
111 struct binder_buffer *buffer;
112
113 BUG_ON(new_buffer->free);
114
115 while (*p) {
116 parent = *p;
117 buffer = rb_entry(parent, struct binder_buffer, rb_node);
118 BUG_ON(buffer->free);
119
120 if (new_buffer->data < buffer->data)
121 p = &parent->rb_left;
122 else if (new_buffer->data > buffer->data)
123 p = &parent->rb_right;
124 else
125 BUG();
126 }
127 rb_link_node(&new_buffer->rb_node, parent, p);
128 rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
129}
130
131static struct binder_buffer *binder_alloc_prepare_to_free_locked(
132 struct binder_alloc *alloc,
133 uintptr_t user_ptr)
134{
135 struct rb_node *n = alloc->allocated_buffers.rb_node;
136 struct binder_buffer *buffer;
137 void *kern_ptr;
138
139 kern_ptr = (void *)(user_ptr - alloc->user_buffer_offset);
140
141 while (n) {
142 buffer = rb_entry(n, struct binder_buffer, rb_node);
143 BUG_ON(buffer->free);
144
145 if (kern_ptr < buffer->data)
146 n = n->rb_left;
147 else if (kern_ptr > buffer->data)
148 n = n->rb_right;
149 else {
150 /*
151 * Guard against user threads attempting to
152 * free the buffer twice
153 */
154 if (buffer->free_in_progress) {
155 pr_err("%d:%d FREE_BUFFER u%016llx user freed buffer twice\n",
156 alloc->pid, current->pid, (u64)user_ptr);
157 return NULL;
158 }
159 buffer->free_in_progress = 1;
160 return buffer;
161 }
162 }
163 return NULL;
164}
165
166/**
167 * binder_alloc_buffer_lookup() - get buffer given user ptr
168 * @alloc: binder_alloc for this proc
169 * @user_ptr: User pointer to buffer data
170 *
171 * Validate userspace pointer to buffer data and return buffer corresponding to
172 * that user pointer. Search the rb tree for buffer that matches user data
173 * pointer.
174 *
175 * Return: Pointer to buffer or NULL
176 */
177struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
178 uintptr_t user_ptr)
179{
180 struct binder_buffer *buffer;
181
182 mutex_lock(&alloc->mutex);
183 buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
184 mutex_unlock(&alloc->mutex);
185 return buffer;
186}
187
188static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
189 void *start, void *end)
190{
191 void *page_addr;
192 unsigned long user_page_addr;
193 struct binder_lru_page *page;
194 struct vm_area_struct *vma = NULL;
195 struct mm_struct *mm = NULL;
196 bool need_mm = false;
197
198 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
199 "%d: %s pages %pK-%pK\n", alloc->pid,
200 allocate ? "allocate" : "free", start, end);
201
202 if (end <= start)
203 return 0;
204
205 trace_binder_update_page_range(alloc, allocate, start, end);
206
207 if (allocate == 0)
208 goto free_range;
209
210 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
211 page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
212 if (!page->page_ptr) {
213 need_mm = true;
214 break;
215 }
216 }
217
218 if (need_mm && mmget_not_zero(alloc->vma_vm_mm))
219 mm = alloc->vma_vm_mm;
220
221 if (mm) {
222 down_write(&mm->mmap_sem);
223 vma = alloc->vma;
224 }
225
226 if (!vma && need_mm) {
227 pr_err("%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
228 alloc->pid);
229 goto err_no_vma;
230 }
231
232 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
233 int ret;
234 bool on_lru;
235 size_t index;
236
237 index = (page_addr - alloc->buffer) / PAGE_SIZE;
238 page = &alloc->pages[index];
239
240 if (page->page_ptr) {
241 trace_binder_alloc_lru_start(alloc, index);
242
243 on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
244 WARN_ON(!on_lru);
245
246 trace_binder_alloc_lru_end(alloc, index);
247 continue;
248 }
249
250 if (WARN_ON(!vma))
251 goto err_page_ptr_cleared;
252
253 trace_binder_alloc_page_start(alloc, index);
254 page->page_ptr = alloc_page(GFP_KERNEL |
255 __GFP_HIGHMEM |
256 __GFP_ZERO);
257 if (!page->page_ptr) {
258 pr_err("%d: binder_alloc_buf failed for page at %pK\n",
259 alloc->pid, page_addr);
260 goto err_alloc_page_failed;
261 }
262 page->alloc = alloc;
263 INIT_LIST_HEAD(&page->lru);
264
265 ret = map_kernel_range_noflush((unsigned long)page_addr,
266 PAGE_SIZE, PAGE_KERNEL,
267 &page->page_ptr);
268 flush_cache_vmap((unsigned long)page_addr,
269 (unsigned long)page_addr + PAGE_SIZE);
270 if (ret != 1) {
271 pr_err("%d: binder_alloc_buf failed to map page at %pK in kernel\n",
272 alloc->pid, page_addr);
273 goto err_map_kernel_failed;
274 }
275 user_page_addr =
276 (uintptr_t)page_addr + alloc->user_buffer_offset;
277 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
278 if (ret) {
279 pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
280 alloc->pid, user_page_addr);
281 goto err_vm_insert_page_failed;
282 }
283
284 if (index + 1 > alloc->pages_high)
285 alloc->pages_high = index + 1;
286
287 trace_binder_alloc_page_end(alloc, index);
288 /* vm_insert_page does not seem to increment the refcount */
289 }
290 if (mm) {
291 up_write(&mm->mmap_sem);
292 mmput(mm);
293 }
294 return 0;
295
296free_range:
297 for (page_addr = end - PAGE_SIZE; page_addr >= start;
298 page_addr -= PAGE_SIZE) {
299 bool ret;
300 size_t index;
301
302 index = (page_addr - alloc->buffer) / PAGE_SIZE;
303 page = &alloc->pages[index];
304
305 trace_binder_free_lru_start(alloc, index);
306
307 ret = list_lru_add(&binder_alloc_lru, &page->lru);
308 WARN_ON(!ret);
309
310 trace_binder_free_lru_end(alloc, index);
311 continue;
312
313err_vm_insert_page_failed:
314 unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
315err_map_kernel_failed:
316 __free_page(page->page_ptr);
317 page->page_ptr = NULL;
318err_alloc_page_failed:
319err_page_ptr_cleared:
320 ;
321 }
322err_no_vma:
323 if (mm) {
324 up_write(&mm->mmap_sem);
325 mmput(mm);
326 }
327 return vma ? -ENOMEM : -ESRCH;
328}
329
330static struct binder_buffer *binder_alloc_new_buf_locked(
331 struct binder_alloc *alloc,
332 size_t data_size,
333 size_t offsets_size,
334 size_t extra_buffers_size,
335 int is_async)
336{
337 struct rb_node *n = alloc->free_buffers.rb_node;
338 struct binder_buffer *buffer;
339 size_t buffer_size;
340 struct rb_node *best_fit = NULL;
341 void *has_page_addr;
342 void *end_page_addr;
343 size_t size, data_offsets_size;
344 int ret;
345
346 if (alloc->vma == NULL) {
347 pr_err("%d: binder_alloc_buf, no vma\n",
348 alloc->pid);
349 return ERR_PTR(-ESRCH);
350 }
351
352 data_offsets_size = ALIGN(data_size, sizeof(void *)) +
353 ALIGN(offsets_size, sizeof(void *));
354
355 if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
356 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
357 "%d: got transaction with invalid size %zd-%zd\n",
358 alloc->pid, data_size, offsets_size);
359 return ERR_PTR(-EINVAL);
360 }
361 size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
362 if (size < data_offsets_size || size < extra_buffers_size) {
363 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
364 "%d: got transaction with invalid extra_buffers_size %zd\n",
365 alloc->pid, extra_buffers_size);
366 return ERR_PTR(-EINVAL);
367 }
368 if (is_async &&
369 alloc->free_async_space < size + sizeof(struct binder_buffer)) {
370 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
371 "%d: binder_alloc_buf size %zd failed, no async space left\n",
372 alloc->pid, size);
373 return ERR_PTR(-ENOSPC);
374 }
375
376 /* Pad 0-size buffers so they get assigned unique addresses */
377 size = max(size, sizeof(void *));
378
379 while (n) {
380 buffer = rb_entry(n, struct binder_buffer, rb_node);
381 BUG_ON(!buffer->free);
382 buffer_size = binder_alloc_buffer_size(alloc, buffer);
383
384 if (size < buffer_size) {
385 best_fit = n;
386 n = n->rb_left;
387 } else if (size > buffer_size)
388 n = n->rb_right;
389 else {
390 best_fit = n;
391 break;
392 }
393 }
394 if (best_fit == NULL) {
395 size_t allocated_buffers = 0;
396 size_t largest_alloc_size = 0;
397 size_t total_alloc_size = 0;
398 size_t free_buffers = 0;
399 size_t largest_free_size = 0;
400 size_t total_free_size = 0;
401
402 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
403 n = rb_next(n)) {
404 buffer = rb_entry(n, struct binder_buffer, rb_node);
405 buffer_size = binder_alloc_buffer_size(alloc, buffer);
406 allocated_buffers++;
407 total_alloc_size += buffer_size;
408 if (buffer_size > largest_alloc_size)
409 largest_alloc_size = buffer_size;
410 }
411 for (n = rb_first(&alloc->free_buffers); n != NULL;
412 n = rb_next(n)) {
413 buffer = rb_entry(n, struct binder_buffer, rb_node);
414 buffer_size = binder_alloc_buffer_size(alloc, buffer);
415 free_buffers++;
416 total_free_size += buffer_size;
417 if (buffer_size > largest_free_size)
418 largest_free_size = buffer_size;
419 }
420 pr_err("%d: binder_alloc_buf size %zd failed, no address space\n",
421 alloc->pid, size);
422 pr_err("allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
423 total_alloc_size, allocated_buffers, largest_alloc_size,
424 total_free_size, free_buffers, largest_free_size);
425 return ERR_PTR(-ENOSPC);
426 }
427 if (n == NULL) {
428 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
429 buffer_size = binder_alloc_buffer_size(alloc, buffer);
430 }
431
432 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
433 "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
434 alloc->pid, size, buffer, buffer_size);
435
436 has_page_addr =
437 (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK);
438 WARN_ON(n && buffer_size != size);
439 end_page_addr =
440 (void *)PAGE_ALIGN((uintptr_t)buffer->data + size);
441 if (end_page_addr > has_page_addr)
442 end_page_addr = has_page_addr;
443 ret = binder_update_page_range(alloc, 1,
444 (void *)PAGE_ALIGN((uintptr_t)buffer->data), end_page_addr);
445 if (ret)
446 return ERR_PTR(ret);
447
448 if (buffer_size != size) {
449 struct binder_buffer *new_buffer;
450
451 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
452 if (!new_buffer) {
453 pr_err("%s: %d failed to alloc new buffer struct\n",
454 __func__, alloc->pid);
455 goto err_alloc_buf_struct_failed;
456 }
457 new_buffer->data = (u8 *)buffer->data + size;
458 list_add(&new_buffer->entry, &buffer->entry);
459 new_buffer->free = 1;
460 binder_insert_free_buffer(alloc, new_buffer);
461 }
462
463 rb_erase(best_fit, &alloc->free_buffers);
464 buffer->free = 0;
465 buffer->free_in_progress = 0;
466 binder_insert_allocated_buffer_locked(alloc, buffer);
467 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
468 "%d: binder_alloc_buf size %zd got %pK\n",
469 alloc->pid, size, buffer);
470 buffer->data_size = data_size;
471 buffer->offsets_size = offsets_size;
472 buffer->async_transaction = is_async;
473 buffer->extra_buffers_size = extra_buffers_size;
474 if (is_async) {
475 alloc->free_async_space -= size + sizeof(struct binder_buffer);
476 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
477 "%d: binder_alloc_buf size %zd async free %zd\n",
478 alloc->pid, size, alloc->free_async_space);
479 }
480 return buffer;
481
482err_alloc_buf_struct_failed:
483 binder_update_page_range(alloc, 0,
484 (void *)PAGE_ALIGN((uintptr_t)buffer->data),
485 end_page_addr);
486 return ERR_PTR(-ENOMEM);
487}
488
489/**
490 * binder_alloc_new_buf() - Allocate a new binder buffer
491 * @alloc: binder_alloc for this proc
492 * @data_size: size of user data buffer
493 * @offsets_size: user specified buffer offset
494 * @extra_buffers_size: size of extra space for meta-data (eg, security context)
495 * @is_async: buffer for async transaction
496 *
497 * Allocate a new buffer given the requested sizes. Returns
498 * the kernel version of the buffer pointer. The size allocated
499 * is the sum of the three given sizes (each rounded up to
500 * pointer-sized boundary)
501 *
502 * Return: The allocated buffer or %NULL if error
503 */
504struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
505 size_t data_size,
506 size_t offsets_size,
507 size_t extra_buffers_size,
508 int is_async)
509{
510 struct binder_buffer *buffer;
511
512 mutex_lock(&alloc->mutex);
513 buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
514 extra_buffers_size, is_async);
515 mutex_unlock(&alloc->mutex);
516 return buffer;
517}
518
519static void *buffer_start_page(struct binder_buffer *buffer)
520{
521 return (void *)((uintptr_t)buffer->data & PAGE_MASK);
522}
523
524static void *prev_buffer_end_page(struct binder_buffer *buffer)
525{
526 return (void *)(((uintptr_t)(buffer->data) - 1) & PAGE_MASK);
527}
528
529static void binder_delete_free_buffer(struct binder_alloc *alloc,
530 struct binder_buffer *buffer)
531{
532 struct binder_buffer *prev, *next = NULL;
533 bool to_free = true;
534 BUG_ON(alloc->buffers.next == &buffer->entry);
535 prev = binder_buffer_prev(buffer);
536 BUG_ON(!prev->free);
537 if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
538 to_free = false;
539 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
540 "%d: merge free, buffer %pK share page with %pK\n",
541 alloc->pid, buffer->data, prev->data);
542 }
543
544 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
545 next = binder_buffer_next(buffer);
546 if (buffer_start_page(next) == buffer_start_page(buffer)) {
547 to_free = false;
548 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
549 "%d: merge free, buffer %pK share page with %pK\n",
550 alloc->pid,
551 buffer->data,
552 next->data);
553 }
554 }
555
556 if (PAGE_ALIGNED(buffer->data)) {
557 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
558 "%d: merge free, buffer start %pK is page aligned\n",
559 alloc->pid, buffer->data);
560 to_free = false;
561 }
562
563 if (to_free) {
564 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
565 "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
566 alloc->pid, buffer->data,
567 prev->data, next ? next->data : NULL);
568 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
569 buffer_start_page(buffer) + PAGE_SIZE);
570 }
571 list_del(&buffer->entry);
572 kfree(buffer);
573}
574
575static void binder_free_buf_locked(struct binder_alloc *alloc,
576 struct binder_buffer *buffer)
577{
578 size_t size, buffer_size;
579
580 buffer_size = binder_alloc_buffer_size(alloc, buffer);
581
582 size = ALIGN(buffer->data_size, sizeof(void *)) +
583 ALIGN(buffer->offsets_size, sizeof(void *)) +
584 ALIGN(buffer->extra_buffers_size, sizeof(void *));
585
586 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
587 "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
588 alloc->pid, buffer, size, buffer_size);
589
590 BUG_ON(buffer->free);
591 BUG_ON(size > buffer_size);
592 BUG_ON(buffer->transaction != NULL);
593 BUG_ON(buffer->data < alloc->buffer);
594 BUG_ON(buffer->data > alloc->buffer + alloc->buffer_size);
595
596 if (buffer->async_transaction) {
597 alloc->free_async_space += size + sizeof(struct binder_buffer);
598
599 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
600 "%d: binder_free_buf size %zd async free %zd\n",
601 alloc->pid, size, alloc->free_async_space);
602 }
603
604 binder_update_page_range(alloc, 0,
605 (void *)PAGE_ALIGN((uintptr_t)buffer->data),
606 (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK));
607
608 rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
609 buffer->free = 1;
610 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
611 struct binder_buffer *next = binder_buffer_next(buffer);
612
613 if (next->free) {
614 rb_erase(&next->rb_node, &alloc->free_buffers);
615 binder_delete_free_buffer(alloc, next);
616 }
617 }
618 if (alloc->buffers.next != &buffer->entry) {
619 struct binder_buffer *prev = binder_buffer_prev(buffer);
620
621 if (prev->free) {
622 binder_delete_free_buffer(alloc, buffer);
623 rb_erase(&prev->rb_node, &alloc->free_buffers);
624 buffer = prev;
625 }
626 }
627 binder_insert_free_buffer(alloc, buffer);
628}
629
630/**
631 * binder_alloc_free_buf() - free a binder buffer
632 * @alloc: binder_alloc for this proc
633 * @buffer: kernel pointer to buffer
634 *
635 * Free the buffer allocated via binder_alloc_new_buffer()
636 */
637void binder_alloc_free_buf(struct binder_alloc *alloc,
638 struct binder_buffer *buffer)
639{
640 mutex_lock(&alloc->mutex);
641 binder_free_buf_locked(alloc, buffer);
642 mutex_unlock(&alloc->mutex);
643}
644
645/**
646 * binder_alloc_mmap_handler() - map virtual address space for proc
647 * @alloc: alloc structure for this proc
648 * @vma: vma passed to mmap()
649 *
650 * Called by binder_mmap() to initialize the space specified in
651 * vma for allocating binder buffers
652 *
653 * Return:
654 * 0 = success
655 * -EBUSY = address space already mapped
656 * -ENOMEM = failed to map memory to given address space
657 */
658int binder_alloc_mmap_handler(struct binder_alloc *alloc,
659 struct vm_area_struct *vma)
660{
661 int ret;
662 struct vm_struct *area;
663 const char *failure_string;
664 struct binder_buffer *buffer;
665
666 mutex_lock(&binder_alloc_mmap_lock);
667 if (alloc->buffer) {
668 ret = -EBUSY;
669 failure_string = "already mapped";
670 goto err_already_mapped;
671 }
672
673 area = get_vm_area(vma->vm_end - vma->vm_start, VM_ALLOC);
674 if (area == NULL) {
675 ret = -ENOMEM;
676 failure_string = "get_vm_area";
677 goto err_get_vm_area_failed;
678 }
679 alloc->buffer = area->addr;
680 alloc->user_buffer_offset =
681 vma->vm_start - (uintptr_t)alloc->buffer;
682 mutex_unlock(&binder_alloc_mmap_lock);
683
684#ifdef CONFIG_CPU_CACHE_VIPT
685 if (cache_is_vipt_aliasing()) {
686 while (CACHE_COLOUR(
687 (vma->vm_start ^ (uint32_t)alloc->buffer))) {
688 pr_info("%s: %d %lx-%lx maps %pK bad alignment\n",
689 __func__, alloc->pid, vma->vm_start,
690 vma->vm_end, alloc->buffer);
691 vma->vm_start += PAGE_SIZE;
692 }
693 }
694#endif
695 alloc->pages = kzalloc(sizeof(alloc->pages[0]) *
696 ((vma->vm_end - vma->vm_start) / PAGE_SIZE),
697 GFP_KERNEL);
698 if (alloc->pages == NULL) {
699 ret = -ENOMEM;
700 failure_string = "alloc page array";
701 goto err_alloc_pages_failed;
702 }
703 alloc->buffer_size = vma->vm_end - vma->vm_start;
704
705 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
706 if (!buffer) {
707 ret = -ENOMEM;
708 failure_string = "alloc buffer struct";
709 goto err_alloc_buf_struct_failed;
710 }
711
712 buffer->data = alloc->buffer;
713 list_add(&buffer->entry, &alloc->buffers);
714 buffer->free = 1;
715 binder_insert_free_buffer(alloc, buffer);
716 alloc->free_async_space = alloc->buffer_size / 2;
717 barrier();
718 alloc->vma = vma;
719 alloc->vma_vm_mm = vma->vm_mm;
720 mmgrab(alloc->vma_vm_mm);
721
722 return 0;
723
724err_alloc_buf_struct_failed:
725 kfree(alloc->pages);
726 alloc->pages = NULL;
727err_alloc_pages_failed:
728 mutex_lock(&binder_alloc_mmap_lock);
729 vfree(alloc->buffer);
730 alloc->buffer = NULL;
731err_get_vm_area_failed:
732err_already_mapped:
733 mutex_unlock(&binder_alloc_mmap_lock);
734 pr_err("%s: %d %lx-%lx %s failed %d\n", __func__,
735 alloc->pid, vma->vm_start, vma->vm_end, failure_string, ret);
736 return ret;
737}
738
739
740void binder_alloc_deferred_release(struct binder_alloc *alloc)
741{
742 struct rb_node *n;
743 int buffers, page_count;
744 struct binder_buffer *buffer;
745
746 BUG_ON(alloc->vma);
747
748 buffers = 0;
749 mutex_lock(&alloc->mutex);
750 while ((n = rb_first(&alloc->allocated_buffers))) {
751 buffer = rb_entry(n, struct binder_buffer, rb_node);
752
753 /* Transaction should already have been freed */
754 BUG_ON(buffer->transaction);
755
756 binder_free_buf_locked(alloc, buffer);
757 buffers++;
758 }
759
760 while (!list_empty(&alloc->buffers)) {
761 buffer = list_first_entry(&alloc->buffers,
762 struct binder_buffer, entry);
763 WARN_ON(!buffer->free);
764
765 list_del(&buffer->entry);
766 WARN_ON_ONCE(!list_empty(&alloc->buffers));
767 kfree(buffer);
768 }
769
770 page_count = 0;
771 if (alloc->pages) {
772 int i;
773
774 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
775 void *page_addr;
776 bool on_lru;
777
778 if (!alloc->pages[i].page_ptr)
779 continue;
780
781 on_lru = list_lru_del(&binder_alloc_lru,
782 &alloc->pages[i].lru);
783 page_addr = alloc->buffer + i * PAGE_SIZE;
784 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
785 "%s: %d: page %d at %pK %s\n",
786 __func__, alloc->pid, i, page_addr,
787 on_lru ? "on lru" : "active");
788 unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
789 __free_page(alloc->pages[i].page_ptr);
790 page_count++;
791 }
792 kfree(alloc->pages);
793 vfree(alloc->buffer);
794 }
795 mutex_unlock(&alloc->mutex);
796 if (alloc->vma_vm_mm)
797 mmdrop(alloc->vma_vm_mm);
798
799 binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
800 "%s: %d buffers %d, pages %d\n",
801 __func__, alloc->pid, buffers, page_count);
802}
803
804static void print_binder_buffer(struct seq_file *m, const char *prefix,
805 struct binder_buffer *buffer)
806{
807 seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
808 prefix, buffer->debug_id, buffer->data,
809 buffer->data_size, buffer->offsets_size,
810 buffer->extra_buffers_size,
811 buffer->transaction ? "active" : "delivered");
812}
813
814/**
815 * binder_alloc_print_allocated() - print buffer info
816 * @m: seq_file for output via seq_printf()
817 * @alloc: binder_alloc for this proc
818 *
819 * Prints information about every buffer associated with
820 * the binder_alloc state to the given seq_file
821 */
822void binder_alloc_print_allocated(struct seq_file *m,
823 struct binder_alloc *alloc)
824{
825 struct rb_node *n;
826
827 mutex_lock(&alloc->mutex);
828 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
829 print_binder_buffer(m, " buffer",
830 rb_entry(n, struct binder_buffer, rb_node));
831 mutex_unlock(&alloc->mutex);
832}
833
834/**
835 * binder_alloc_print_pages() - print page usage
836 * @m: seq_file for output via seq_printf()
837 * @alloc: binder_alloc for this proc
838 */
839void binder_alloc_print_pages(struct seq_file *m,
840 struct binder_alloc *alloc)
841{
842 struct binder_lru_page *page;
843 int i;
844 int active = 0;
845 int lru = 0;
846 int free = 0;
847
848 mutex_lock(&alloc->mutex);
849 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
850 page = &alloc->pages[i];
851 if (!page->page_ptr)
852 free++;
853 else if (list_empty(&page->lru))
854 active++;
855 else
856 lru++;
857 }
858 mutex_unlock(&alloc->mutex);
859 seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
860 seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);
861}
862
863/**
864 * binder_alloc_get_allocated_count() - return count of buffers
865 * @alloc: binder_alloc for this proc
866 *
867 * Return: count of allocated buffers
868 */
869int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
870{
871 struct rb_node *n;
872 int count = 0;
873
874 mutex_lock(&alloc->mutex);
875 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
876 count++;
877 mutex_unlock(&alloc->mutex);
878 return count;
879}
880
881
882/**
883 * binder_alloc_vma_close() - invalidate address space
884 * @alloc: binder_alloc for this proc
885 *
886 * Called from binder_vma_close() when releasing address space.
887 * Clears alloc->vma to prevent new incoming transactions from
888 * allocating more buffers.
889 */
890void binder_alloc_vma_close(struct binder_alloc *alloc)
891{
892 WRITE_ONCE(alloc->vma, NULL);
893}
894
895/**
896 * binder_alloc_free_page() - shrinker callback to free pages
897 * @item: item to free
898 * @lock: lock protecting the item
899 * @cb_arg: callback argument
900 *
901 * Called from list_lru_walk() in binder_shrink_scan() to free
902 * up pages when the system is under memory pressure.
903 */
904enum lru_status binder_alloc_free_page(struct list_head *item,
905 struct list_lru_one *lru,
906 spinlock_t *lock,
907 void *cb_arg)
908{
909 struct mm_struct *mm = NULL;
910 struct binder_lru_page *page = container_of(item,
911 struct binder_lru_page,
912 lru);
913 struct binder_alloc *alloc;
914 uintptr_t page_addr;
915 size_t index;
916 struct vm_area_struct *vma;
917
918 alloc = page->alloc;
919 if (!mutex_trylock(&alloc->mutex))
920 goto err_get_alloc_mutex_failed;
921
922 if (!page->page_ptr)
923 goto err_page_already_freed;
924
925 index = page - alloc->pages;
926 page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
927 vma = alloc->vma;
928 if (vma) {
929 if (!mmget_not_zero(alloc->vma_vm_mm))
930 goto err_mmget;
931 mm = alloc->vma_vm_mm;
932 if (!down_write_trylock(&mm->mmap_sem))
933 goto err_down_write_mmap_sem_failed;
934 }
935
936 list_lru_isolate(lru, item);
937 spin_unlock(lock);
938
939 if (vma) {
940 trace_binder_unmap_user_start(alloc, index);
941
942 zap_page_range(vma,
943 page_addr + alloc->user_buffer_offset,
944 PAGE_SIZE);
945
946 trace_binder_unmap_user_end(alloc, index);
947
948 up_write(&mm->mmap_sem);
949 mmput(mm);
950 }
951
952 trace_binder_unmap_kernel_start(alloc, index);
953
954 unmap_kernel_range(page_addr, PAGE_SIZE);
955 __free_page(page->page_ptr);
956 page->page_ptr = NULL;
957
958 trace_binder_unmap_kernel_end(alloc, index);
959
960 spin_lock(lock);
961 mutex_unlock(&alloc->mutex);
962 return LRU_REMOVED_RETRY;
963
964err_down_write_mmap_sem_failed:
965 mmput_async(mm);
966err_mmget:
967err_page_already_freed:
968 mutex_unlock(&alloc->mutex);
969err_get_alloc_mutex_failed:
970 return LRU_SKIP;
971}
972
973static unsigned long
974binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
975{
976 unsigned long ret = list_lru_count(&binder_alloc_lru);
977 return ret;
978}
979
980static unsigned long
981binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
982{
983 unsigned long ret;
984
985 ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
986 NULL, sc->nr_to_scan);
987 return ret;
988}
989
990static struct shrinker binder_shrinker = {
991 .count_objects = binder_shrink_count,
992 .scan_objects = binder_shrink_scan,
993 .seeks = DEFAULT_SEEKS,
994};
995
996/**
997 * binder_alloc_init() - called by binder_open() for per-proc initialization
998 * @alloc: binder_alloc for this proc
999 *
1000 * Called from binder_open() to initialize binder_alloc fields for
1001 * new binder proc
1002 */
1003void binder_alloc_init(struct binder_alloc *alloc)
1004{
1005 alloc->pid = current->group_leader->pid;
1006 mutex_init(&alloc->mutex);
1007 INIT_LIST_HEAD(&alloc->buffers);
1008}
1009
1010int binder_alloc_shrinker_init(void)
1011{
1012 int ret = list_lru_init(&binder_alloc_lru);
1013
1014 if (ret == 0) {
1015 ret = register_shrinker(&binder_shrinker);
1016 if (ret)
1017 list_lru_destroy(&binder_alloc_lru);
1018 }
1019 return ret;
1020}
1// SPDX-License-Identifier: GPL-2.0-only
2/* binder_alloc.c
3 *
4 * Android IPC Subsystem
5 *
6 * Copyright (C) 2007-2017 Google, Inc.
7 */
8
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
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"
28
29struct list_lru binder_freelist;
30
31static DEFINE_MUTEX(binder_alloc_mmap_lock);
32
33enum {
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,
38};
39static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
40
41module_param_named(debug_mask, binder_alloc_debug_mask,
42 uint, 0644);
43
44#define binder_alloc_debug(mask, x...) \
45 do { \
46 if (binder_alloc_debug_mask & mask) \
47 pr_info_ratelimited(x); \
48 } while (0)
49
50static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
51{
52 return list_entry(buffer->entry.next, struct binder_buffer, entry);
53}
54
55static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
56{
57 return list_entry(buffer->entry.prev, struct binder_buffer, entry);
58}
59
60static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
61 struct binder_buffer *buffer)
62{
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;
66}
67
68static void binder_insert_free_buffer(struct binder_alloc *alloc,
69 struct binder_buffer *new_buffer)
70{
71 struct rb_node **p = &alloc->free_buffers.rb_node;
72 struct rb_node *parent = NULL;
73 struct binder_buffer *buffer;
74 size_t buffer_size;
75 size_t new_buffer_size;
76
77 BUG_ON(!new_buffer->free);
78
79 new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
80
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);
84
85 while (*p) {
86 parent = *p;
87 buffer = rb_entry(parent, struct binder_buffer, rb_node);
88 BUG_ON(!buffer->free);
89
90 buffer_size = binder_alloc_buffer_size(alloc, buffer);
91
92 if (new_buffer_size < buffer_size)
93 p = &parent->rb_left;
94 else
95 p = &parent->rb_right;
96 }
97 rb_link_node(&new_buffer->rb_node, parent, p);
98 rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
99}
100
101static void binder_insert_allocated_buffer_locked(
102 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
103{
104 struct rb_node **p = &alloc->allocated_buffers.rb_node;
105 struct rb_node *parent = NULL;
106 struct binder_buffer *buffer;
107
108 BUG_ON(new_buffer->free);
109
110 while (*p) {
111 parent = *p;
112 buffer = rb_entry(parent, struct binder_buffer, rb_node);
113 BUG_ON(buffer->free);
114
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;
119 else
120 BUG();
121 }
122 rb_link_node(&new_buffer->rb_node, parent, p);
123 rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
124}
125
126static struct binder_buffer *binder_alloc_prepare_to_free_locked(
127 struct binder_alloc *alloc,
128 unsigned long user_ptr)
129{
130 struct rb_node *n = alloc->allocated_buffers.rb_node;
131 struct binder_buffer *buffer;
132
133 while (n) {
134 buffer = rb_entry(n, struct binder_buffer, rb_node);
135 BUG_ON(buffer->free);
136
137 if (user_ptr < buffer->user_data) {
138 n = n->rb_left;
139 } else if (user_ptr > buffer->user_data) {
140 n = n->rb_right;
141 } else {
142 /*
143 * Guard against user threads attempting to
144 * free the buffer when in use by kernel or
145 * after it's already been freed.
146 */
147 if (!buffer->allow_user_free)
148 return ERR_PTR(-EPERM);
149 buffer->allow_user_free = 0;
150 return buffer;
151 }
152 }
153 return NULL;
154}
155
156/**
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
160 *
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
163 * pointer.
164 *
165 * Return: Pointer to buffer or NULL
166 */
167struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
168 unsigned long user_ptr)
169{
170 struct binder_buffer *buffer;
171
172 spin_lock(&alloc->lock);
173 buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
174 spin_unlock(&alloc->lock);
175 return buffer;
176}
177
178static inline void
179binder_set_installed_page(struct binder_lru_page *lru_page,
180 struct page *page)
181{
182 /* Pairs with acquire in binder_get_installed_page() */
183 smp_store_release(&lru_page->page_ptr, page);
184}
185
186static inline struct page *
187binder_get_installed_page(struct binder_lru_page *lru_page)
188{
189 /* Pairs with release in binder_set_installed_page() */
190 return smp_load_acquire(&lru_page->page_ptr);
191}
192
193static void binder_lru_freelist_add(struct binder_alloc *alloc,
194 unsigned long start, unsigned long end)
195{
196 struct binder_lru_page *page;
197 unsigned long page_addr;
198
199 trace_binder_update_page_range(alloc, false, start, end);
200
201 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
202 size_t index;
203 int ret;
204
205 index = (page_addr - alloc->buffer) / PAGE_SIZE;
206 page = &alloc->pages[index];
207
208 if (!binder_get_installed_page(page))
209 continue;
210
211 trace_binder_free_lru_start(alloc, index);
212
213 ret = list_lru_add_obj(&binder_freelist, &page->lru);
214 WARN_ON(!ret);
215
216 trace_binder_free_lru_end(alloc, index);
217 }
218}
219
220static int binder_install_single_page(struct binder_alloc *alloc,
221 struct binder_lru_page *lru_page,
222 unsigned long addr)
223{
224 struct page *page;
225 int ret = 0;
226
227 if (!mmget_not_zero(alloc->mm))
228 return -ESRCH;
229
230 /*
231 * Protected with mmap_sem in write mode as multiple tasks
232 * might race to install the same page.
233 */
234 mmap_write_lock(alloc->mm);
235 if (binder_get_installed_page(lru_page))
236 goto out;
237
238 if (!alloc->vma) {
239 pr_err("%d: %s failed, no vma\n", alloc->pid, __func__);
240 ret = -ESRCH;
241 goto out;
242 }
243
244 page = alloc_page(GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
245 if (!page) {
246 pr_err("%d: failed to allocate page\n", alloc->pid);
247 ret = -ENOMEM;
248 goto out;
249 }
250
251 ret = vm_insert_page(alloc->vma, addr, page);
252 if (ret) {
253 pr_err("%d: %s failed to insert page at offset %lx with %d\n",
254 alloc->pid, __func__, addr - alloc->buffer, ret);
255 __free_page(page);
256 ret = -ENOMEM;
257 goto out;
258 }
259
260 /* Mark page installation complete and safe to use */
261 binder_set_installed_page(lru_page, page);
262out:
263 mmap_write_unlock(alloc->mm);
264 mmput_async(alloc->mm);
265 return ret;
266}
267
268static int binder_install_buffer_pages(struct binder_alloc *alloc,
269 struct binder_buffer *buffer,
270 size_t size)
271{
272 struct binder_lru_page *page;
273 unsigned long start, final;
274 unsigned long page_addr;
275
276 start = buffer->user_data & PAGE_MASK;
277 final = PAGE_ALIGN(buffer->user_data + size);
278
279 for (page_addr = start; page_addr < final; page_addr += PAGE_SIZE) {
280 unsigned long index;
281 int ret;
282
283 index = (page_addr - alloc->buffer) / PAGE_SIZE;
284 page = &alloc->pages[index];
285
286 if (binder_get_installed_page(page))
287 continue;
288
289 trace_binder_alloc_page_start(alloc, index);
290
291 ret = binder_install_single_page(alloc, page, page_addr);
292 if (ret)
293 return ret;
294
295 trace_binder_alloc_page_end(alloc, index);
296 }
297
298 return 0;
299}
300
301/* The range of pages should exclude those shared with other buffers */
302static void binder_lru_freelist_del(struct binder_alloc *alloc,
303 unsigned long start, unsigned long end)
304{
305 struct binder_lru_page *page;
306 unsigned long page_addr;
307
308 trace_binder_update_page_range(alloc, true, start, end);
309
310 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
311 unsigned long index;
312 bool on_lru;
313
314 index = (page_addr - alloc->buffer) / PAGE_SIZE;
315 page = &alloc->pages[index];
316
317 if (page->page_ptr) {
318 trace_binder_alloc_lru_start(alloc, index);
319
320 on_lru = list_lru_del_obj(&binder_freelist, &page->lru);
321 WARN_ON(!on_lru);
322
323 trace_binder_alloc_lru_end(alloc, index);
324 continue;
325 }
326
327 if (index + 1 > alloc->pages_high)
328 alloc->pages_high = index + 1;
329 }
330}
331
332static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
333 struct vm_area_struct *vma)
334{
335 /* pairs with smp_load_acquire in binder_alloc_get_vma() */
336 smp_store_release(&alloc->vma, vma);
337}
338
339static inline struct vm_area_struct *binder_alloc_get_vma(
340 struct binder_alloc *alloc)
341{
342 /* pairs with smp_store_release in binder_alloc_set_vma() */
343 return smp_load_acquire(&alloc->vma);
344}
345
346static void debug_no_space_locked(struct binder_alloc *alloc)
347{
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;
355 size_t buffer_size;
356 struct rb_node *n;
357
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);
361 allocated_buffers++;
362 total_alloc_size += buffer_size;
363 if (buffer_size > largest_alloc_size)
364 largest_alloc_size = buffer_size;
365 }
366
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);
370 free_buffers++;
371 total_free_size += buffer_size;
372 if (buffer_size > largest_free_size)
373 largest_free_size = buffer_size;
374 }
375
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);
381}
382
383static bool debug_low_async_space_locked(struct binder_alloc *alloc)
384{
385 /*
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.
391 */
392 struct binder_buffer *buffer;
393 size_t total_alloc_size = 0;
394 int pid = current->tgid;
395 size_t num_buffers = 0;
396 struct rb_node *n;
397
398 /*
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).
401 */
402 if (alloc->free_async_space >= alloc->buffer_size / 10) {
403 alloc->oneway_spam_detected = false;
404 return false;
405 }
406
407 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
408 n = rb_next(n)) {
409 buffer = rb_entry(n, struct binder_buffer, rb_node);
410 if (buffer->pid != pid)
411 continue;
412 if (!buffer->async_transaction)
413 continue;
414 total_alloc_size += binder_alloc_buffer_size(alloc, buffer);
415 num_buffers++;
416 }
417
418 /*
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.
422 */
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;
429 return true;
430 }
431 }
432 return false;
433}
434
435/* Callers preallocate @new_buffer, it is freed by this function if unused */
436static struct binder_buffer *binder_alloc_new_buf_locked(
437 struct binder_alloc *alloc,
438 struct binder_buffer *new_buffer,
439 size_t size,
440 int is_async)
441{
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;
447 size_t buffer_size;
448
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",
452 alloc->pid, size);
453 buffer = ERR_PTR(-ENOSPC);
454 goto out;
455 }
456
457 while (n) {
458 buffer = rb_entry(n, struct binder_buffer, rb_node);
459 BUG_ON(!buffer->free);
460 buffer_size = binder_alloc_buffer_size(alloc, buffer);
461
462 if (size < buffer_size) {
463 best_fit = n;
464 n = n->rb_left;
465 } else if (size > buffer_size) {
466 n = n->rb_right;
467 } else {
468 best_fit = n;
469 break;
470 }
471 }
472
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",
476 alloc->pid, size);
477 debug_no_space_locked(alloc);
478 buffer = ERR_PTR(-ENOSPC);
479 goto out;
480 }
481
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);
486
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);
492 new_buffer = NULL;
493 }
494
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);
498
499 /*
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.
504 */
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));
509
510 rb_erase(&buffer->rb_node, &alloc->free_buffers);
511 buffer->free = 0;
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;
516 if (is_async) {
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;
523 }
524
525out:
526 /* Discard possibly unused new_buffer */
527 kfree(new_buffer);
528 return buffer;
529}
530
531/* Calculate the sanitized total size, returns 0 for invalid request */
532static inline size_t sanitized_size(size_t data_size,
533 size_t offsets_size,
534 size_t extra_buffers_size)
535{
536 size_t total, tmp;
537
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)
542 return 0;
543 total = tmp + ALIGN(extra_buffers_size, sizeof(void *));
544 if (total < tmp || total < extra_buffers_size)
545 return 0;
546
547 /* Pad 0-sized buffers so they get a unique address */
548 total = max(total, sizeof(void *));
549
550 return total;
551}
552
553/**
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
560 *
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)
565 *
566 * Return: The allocated buffer or %ERR_PTR(-errno) if error
567 */
568struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
569 size_t data_size,
570 size_t offsets_size,
571 size_t extra_buffers_size,
572 int is_async)
573{
574 struct binder_buffer *buffer, *next;
575 size_t size;
576 int ret;
577
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",
582 alloc->pid);
583 return ERR_PTR(-ESRCH);
584 }
585
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,
591 extra_buffers_size);
592 return ERR_PTR(-EINVAL);
593 }
594
595 /* Preallocate the next buffer */
596 next = kzalloc(sizeof(*next), GFP_KERNEL);
597 if (!next)
598 return ERR_PTR(-ENOMEM);
599
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);
604 goto out;
605 }
606
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);
612
613 ret = binder_install_buffer_pages(alloc, buffer, size);
614 if (ret) {
615 binder_alloc_free_buf(alloc, buffer);
616 buffer = ERR_PTR(ret);
617 }
618out:
619 return buffer;
620}
621
622static unsigned long buffer_start_page(struct binder_buffer *buffer)
623{
624 return buffer->user_data & PAGE_MASK;
625}
626
627static unsigned long prev_buffer_end_page(struct binder_buffer *buffer)
628{
629 return (buffer->user_data - 1) & PAGE_MASK;
630}
631
632static void binder_delete_free_buffer(struct binder_alloc *alloc,
633 struct binder_buffer *buffer)
634{
635 struct binder_buffer *prev, *next;
636
637 if (PAGE_ALIGNED(buffer->user_data))
638 goto skip_freelist;
639
640 BUG_ON(alloc->buffers.next == &buffer->entry);
641 prev = binder_buffer_prev(buffer);
642 BUG_ON(!prev->free);
643 if (prev_buffer_end_page(prev) == buffer_start_page(buffer))
644 goto skip_freelist;
645
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))
649 goto skip_freelist;
650 }
651
652 binder_lru_freelist_add(alloc, buffer_start_page(buffer),
653 buffer_start_page(buffer) + PAGE_SIZE);
654skip_freelist:
655 list_del(&buffer->entry);
656 kfree(buffer);
657}
658
659static void binder_free_buf_locked(struct binder_alloc *alloc,
660 struct binder_buffer *buffer)
661{
662 size_t size, buffer_size;
663
664 buffer_size = binder_alloc_buffer_size(alloc, buffer);
665
666 size = ALIGN(buffer->data_size, sizeof(void *)) +
667 ALIGN(buffer->offsets_size, sizeof(void *)) +
668 ALIGN(buffer->extra_buffers_size, sizeof(void *));
669
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);
673
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);
679
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);
685 }
686
687 binder_lru_freelist_add(alloc, PAGE_ALIGN(buffer->user_data),
688 (buffer->user_data + buffer_size) & PAGE_MASK);
689
690 rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
691 buffer->free = 1;
692 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
693 struct binder_buffer *next = binder_buffer_next(buffer);
694
695 if (next->free) {
696 rb_erase(&next->rb_node, &alloc->free_buffers);
697 binder_delete_free_buffer(alloc, next);
698 }
699 }
700 if (alloc->buffers.next != &buffer->entry) {
701 struct binder_buffer *prev = binder_buffer_prev(buffer);
702
703 if (prev->free) {
704 binder_delete_free_buffer(alloc, buffer);
705 rb_erase(&prev->rb_node, &alloc->free_buffers);
706 buffer = prev;
707 }
708 }
709 binder_insert_free_buffer(alloc, buffer);
710}
711
712/**
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
718 *
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.
722 *
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[]
727 * cannot change.
728 *
729 * Return: struct page
730 */
731static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
732 struct binder_buffer *buffer,
733 binder_size_t buffer_offset,
734 pgoff_t *pgoffp)
735{
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;
741
742 lru_page = &alloc->pages[index];
743 *pgoffp = pgoff;
744 return lru_page->page_ptr;
745}
746
747/**
748 * binder_alloc_clear_buf() - zero out buffer
749 * @alloc: binder_alloc for this proc
750 * @buffer: binder buffer to be cleared
751 *
752 * memset the given buffer to 0
753 */
754static void binder_alloc_clear_buf(struct binder_alloc *alloc,
755 struct binder_buffer *buffer)
756{
757 size_t bytes = binder_alloc_buffer_size(alloc, buffer);
758 binder_size_t buffer_offset = 0;
759
760 while (bytes) {
761 unsigned long size;
762 struct page *page;
763 pgoff_t pgoff;
764
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);
769 bytes -= size;
770 buffer_offset += size;
771 }
772}
773
774/**
775 * binder_alloc_free_buf() - free a binder buffer
776 * @alloc: binder_alloc for this proc
777 * @buffer: kernel pointer to buffer
778 *
779 * Free the buffer allocated via binder_alloc_new_buf()
780 */
781void binder_alloc_free_buf(struct binder_alloc *alloc,
782 struct binder_buffer *buffer)
783{
784 /*
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.
791 */
792 if (buffer->clear_on_free) {
793 binder_alloc_clear_buf(alloc, buffer);
794 buffer->clear_on_free = false;
795 }
796 spin_lock(&alloc->lock);
797 binder_free_buf_locked(alloc, buffer);
798 spin_unlock(&alloc->lock);
799}
800
801/**
802 * binder_alloc_mmap_handler() - map virtual address space for proc
803 * @alloc: alloc structure for this proc
804 * @vma: vma passed to mmap()
805 *
806 * Called by binder_mmap() to initialize the space specified in
807 * vma for allocating binder buffers
808 *
809 * Return:
810 * 0 = success
811 * -EBUSY = address space already mapped
812 * -ENOMEM = failed to map memory to given address space
813 */
814int binder_alloc_mmap_handler(struct binder_alloc *alloc,
815 struct vm_area_struct *vma)
816{
817 struct binder_buffer *buffer;
818 const char *failure_string;
819 int ret, i;
820
821 if (unlikely(vma->vm_mm != alloc->mm)) {
822 ret = -EINVAL;
823 failure_string = "invalid vma->vm_mm";
824 goto err_invalid_mm;
825 }
826
827 mutex_lock(&binder_alloc_mmap_lock);
828 if (alloc->buffer_size) {
829 ret = -EBUSY;
830 failure_string = "already mapped";
831 goto err_already_mapped;
832 }
833 alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
834 SZ_4M);
835 mutex_unlock(&binder_alloc_mmap_lock);
836
837 alloc->buffer = vma->vm_start;
838
839 alloc->pages = kvcalloc(alloc->buffer_size / PAGE_SIZE,
840 sizeof(alloc->pages[0]),
841 GFP_KERNEL);
842 if (alloc->pages == NULL) {
843 ret = -ENOMEM;
844 failure_string = "alloc page array";
845 goto err_alloc_pages_failed;
846 }
847
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);
851 }
852
853 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
854 if (!buffer) {
855 ret = -ENOMEM;
856 failure_string = "alloc buffer struct";
857 goto err_alloc_buf_struct_failed;
858 }
859
860 buffer->user_data = alloc->buffer;
861 list_add(&buffer->entry, &alloc->buffers);
862 buffer->free = 1;
863 binder_insert_free_buffer(alloc, buffer);
864 alloc->free_async_space = alloc->buffer_size / 2;
865
866 /* Signal binder_alloc is fully initialized */
867 binder_alloc_set_vma(alloc, vma);
868
869 return 0;
870
871err_alloc_buf_struct_failed:
872 kvfree(alloc->pages);
873 alloc->pages = NULL;
874err_alloc_pages_failed:
875 alloc->buffer = 0;
876 mutex_lock(&binder_alloc_mmap_lock);
877 alloc->buffer_size = 0;
878err_already_mapped:
879 mutex_unlock(&binder_alloc_mmap_lock);
880err_invalid_mm:
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);
885 return ret;
886}
887
888
889void binder_alloc_deferred_release(struct binder_alloc *alloc)
890{
891 struct rb_node *n;
892 int buffers, page_count;
893 struct binder_buffer *buffer;
894
895 buffers = 0;
896 spin_lock(&alloc->lock);
897 BUG_ON(alloc->vma);
898
899 while ((n = rb_first(&alloc->allocated_buffers))) {
900 buffer = rb_entry(n, struct binder_buffer, rb_node);
901
902 /* Transaction should already have been freed */
903 BUG_ON(buffer->transaction);
904
905 if (buffer->clear_on_free) {
906 binder_alloc_clear_buf(alloc, buffer);
907 buffer->clear_on_free = false;
908 }
909 binder_free_buf_locked(alloc, buffer);
910 buffers++;
911 }
912
913 while (!list_empty(&alloc->buffers)) {
914 buffer = list_first_entry(&alloc->buffers,
915 struct binder_buffer, entry);
916 WARN_ON(!buffer->free);
917
918 list_del(&buffer->entry);
919 WARN_ON_ONCE(!list_empty(&alloc->buffers));
920 kfree(buffer);
921 }
922
923 page_count = 0;
924 if (alloc->pages) {
925 int i;
926
927 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
928 bool on_lru;
929
930 if (!alloc->pages[i].page_ptr)
931 continue;
932
933 on_lru = list_lru_del_obj(&binder_freelist,
934 &alloc->pages[i].lru);
935 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
936 "%s: %d: page %d %s\n",
937 __func__, alloc->pid, i,
938 on_lru ? "on lru" : "active");
939 __free_page(alloc->pages[i].page_ptr);
940 page_count++;
941 }
942 }
943 spin_unlock(&alloc->lock);
944 kvfree(alloc->pages);
945 if (alloc->mm)
946 mmdrop(alloc->mm);
947
948 binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
949 "%s: %d buffers %d, pages %d\n",
950 __func__, alloc->pid, buffers, page_count);
951}
952
953/**
954 * binder_alloc_print_allocated() - print buffer info
955 * @m: seq_file for output via seq_printf()
956 * @alloc: binder_alloc for this proc
957 *
958 * Prints information about every buffer associated with
959 * the binder_alloc state to the given seq_file
960 */
961void binder_alloc_print_allocated(struct seq_file *m,
962 struct binder_alloc *alloc)
963{
964 struct binder_buffer *buffer;
965 struct rb_node *n;
966
967 spin_lock(&alloc->lock);
968 for (n = rb_first(&alloc->allocated_buffers); n; n = rb_next(n)) {
969 buffer = rb_entry(n, struct binder_buffer, rb_node);
970 seq_printf(m, " buffer %d: %lx size %zd:%zd:%zd %s\n",
971 buffer->debug_id,
972 buffer->user_data - alloc->buffer,
973 buffer->data_size, buffer->offsets_size,
974 buffer->extra_buffers_size,
975 buffer->transaction ? "active" : "delivered");
976 }
977 spin_unlock(&alloc->lock);
978}
979
980/**
981 * binder_alloc_print_pages() - print page usage
982 * @m: seq_file for output via seq_printf()
983 * @alloc: binder_alloc for this proc
984 */
985void binder_alloc_print_pages(struct seq_file *m,
986 struct binder_alloc *alloc)
987{
988 struct binder_lru_page *page;
989 int i;
990 int active = 0;
991 int lru = 0;
992 int free = 0;
993
994 spin_lock(&alloc->lock);
995 /*
996 * Make sure the binder_alloc is fully initialized, otherwise we might
997 * read inconsistent state.
998 */
999 if (binder_alloc_get_vma(alloc) != NULL) {
1000 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
1001 page = &alloc->pages[i];
1002 if (!page->page_ptr)
1003 free++;
1004 else if (list_empty(&page->lru))
1005 active++;
1006 else
1007 lru++;
1008 }
1009 }
1010 spin_unlock(&alloc->lock);
1011 seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
1012 seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);
1013}
1014
1015/**
1016 * binder_alloc_get_allocated_count() - return count of buffers
1017 * @alloc: binder_alloc for this proc
1018 *
1019 * Return: count of allocated buffers
1020 */
1021int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
1022{
1023 struct rb_node *n;
1024 int count = 0;
1025
1026 spin_lock(&alloc->lock);
1027 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
1028 count++;
1029 spin_unlock(&alloc->lock);
1030 return count;
1031}
1032
1033
1034/**
1035 * binder_alloc_vma_close() - invalidate address space
1036 * @alloc: binder_alloc for this proc
1037 *
1038 * Called from binder_vma_close() when releasing address space.
1039 * Clears alloc->vma to prevent new incoming transactions from
1040 * allocating more buffers.
1041 */
1042void binder_alloc_vma_close(struct binder_alloc *alloc)
1043{
1044 binder_alloc_set_vma(alloc, NULL);
1045}
1046
1047/**
1048 * binder_alloc_free_page() - shrinker callback to free pages
1049 * @item: item to free
1050 * @lru: list_lru instance of the item
1051 * @cb_arg: callback argument
1052 *
1053 * Called from list_lru_walk() in binder_shrink_scan() to free
1054 * up pages when the system is under memory pressure.
1055 */
1056enum lru_status binder_alloc_free_page(struct list_head *item,
1057 struct list_lru_one *lru,
1058 void *cb_arg)
1059 __must_hold(&lru->lock)
1060{
1061 struct binder_lru_page *page = container_of(item, typeof(*page), lru);
1062 struct binder_alloc *alloc = page->alloc;
1063 struct mm_struct *mm = alloc->mm;
1064 struct vm_area_struct *vma;
1065 struct page *page_to_free;
1066 unsigned long page_addr;
1067 size_t index;
1068
1069 if (!mmget_not_zero(mm))
1070 goto err_mmget;
1071 if (!mmap_read_trylock(mm))
1072 goto err_mmap_read_lock_failed;
1073 if (!spin_trylock(&alloc->lock))
1074 goto err_get_alloc_lock_failed;
1075 if (!page->page_ptr)
1076 goto err_page_already_freed;
1077
1078 index = page - alloc->pages;
1079 page_addr = alloc->buffer + index * PAGE_SIZE;
1080
1081 vma = vma_lookup(mm, page_addr);
1082 if (vma && vma != binder_alloc_get_vma(alloc))
1083 goto err_invalid_vma;
1084
1085 trace_binder_unmap_kernel_start(alloc, index);
1086
1087 page_to_free = page->page_ptr;
1088 page->page_ptr = NULL;
1089
1090 trace_binder_unmap_kernel_end(alloc, index);
1091
1092 list_lru_isolate(lru, item);
1093 spin_unlock(&alloc->lock);
1094 spin_unlock(&lru->lock);
1095
1096 if (vma) {
1097 trace_binder_unmap_user_start(alloc, index);
1098
1099 zap_page_range_single(vma, page_addr, PAGE_SIZE, NULL);
1100
1101 trace_binder_unmap_user_end(alloc, index);
1102 }
1103
1104 mmap_read_unlock(mm);
1105 mmput_async(mm);
1106 __free_page(page_to_free);
1107
1108 return LRU_REMOVED_RETRY;
1109
1110err_invalid_vma:
1111err_page_already_freed:
1112 spin_unlock(&alloc->lock);
1113err_get_alloc_lock_failed:
1114 mmap_read_unlock(mm);
1115err_mmap_read_lock_failed:
1116 mmput_async(mm);
1117err_mmget:
1118 return LRU_SKIP;
1119}
1120
1121static unsigned long
1122binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
1123{
1124 return list_lru_count(&binder_freelist);
1125}
1126
1127static unsigned long
1128binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1129{
1130 return list_lru_walk(&binder_freelist, binder_alloc_free_page,
1131 NULL, sc->nr_to_scan);
1132}
1133
1134static struct shrinker *binder_shrinker;
1135
1136/**
1137 * binder_alloc_init() - called by binder_open() for per-proc initialization
1138 * @alloc: binder_alloc for this proc
1139 *
1140 * Called from binder_open() to initialize binder_alloc fields for
1141 * new binder proc
1142 */
1143void binder_alloc_init(struct binder_alloc *alloc)
1144{
1145 alloc->pid = current->group_leader->pid;
1146 alloc->mm = current->mm;
1147 mmgrab(alloc->mm);
1148 spin_lock_init(&alloc->lock);
1149 INIT_LIST_HEAD(&alloc->buffers);
1150}
1151
1152int binder_alloc_shrinker_init(void)
1153{
1154 int ret;
1155
1156 ret = list_lru_init(&binder_freelist);
1157 if (ret)
1158 return ret;
1159
1160 binder_shrinker = shrinker_alloc(0, "android-binder");
1161 if (!binder_shrinker) {
1162 list_lru_destroy(&binder_freelist);
1163 return -ENOMEM;
1164 }
1165
1166 binder_shrinker->count_objects = binder_shrink_count;
1167 binder_shrinker->scan_objects = binder_shrink_scan;
1168
1169 shrinker_register(binder_shrinker);
1170
1171 return 0;
1172}
1173
1174void binder_alloc_shrinker_exit(void)
1175{
1176 shrinker_free(binder_shrinker);
1177 list_lru_destroy(&binder_freelist);
1178}
1179
1180/**
1181 * check_buffer() - verify that buffer/offset is safe to access
1182 * @alloc: binder_alloc for this proc
1183 * @buffer: binder buffer to be accessed
1184 * @offset: offset into @buffer data
1185 * @bytes: bytes to access from offset
1186 *
1187 * Check that the @offset/@bytes are within the size of the given
1188 * @buffer and that the buffer is currently active and not freeable.
1189 * Offsets must also be multiples of sizeof(u32). The kernel is
1190 * allowed to touch the buffer in two cases:
1191 *
1192 * 1) when the buffer is being created:
1193 * (buffer->free == 0 && buffer->allow_user_free == 0)
1194 * 2) when the buffer is being torn down:
1195 * (buffer->free == 0 && buffer->transaction == NULL).
1196 *
1197 * Return: true if the buffer is safe to access
1198 */
1199static inline bool check_buffer(struct binder_alloc *alloc,
1200 struct binder_buffer *buffer,
1201 binder_size_t offset, size_t bytes)
1202{
1203 size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1204
1205 return buffer_size >= bytes &&
1206 offset <= buffer_size - bytes &&
1207 IS_ALIGNED(offset, sizeof(u32)) &&
1208 !buffer->free &&
1209 (!buffer->allow_user_free || !buffer->transaction);
1210}
1211
1212/**
1213 * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1214 * @alloc: binder_alloc for this proc
1215 * @buffer: binder buffer to be accessed
1216 * @buffer_offset: offset into @buffer data
1217 * @from: userspace pointer to source buffer
1218 * @bytes: bytes to copy
1219 *
1220 * Copy bytes from source userspace to target buffer.
1221 *
1222 * Return: bytes remaining to be copied
1223 */
1224unsigned long
1225binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1226 struct binder_buffer *buffer,
1227 binder_size_t buffer_offset,
1228 const void __user *from,
1229 size_t bytes)
1230{
1231 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1232 return bytes;
1233
1234 while (bytes) {
1235 unsigned long size;
1236 unsigned long ret;
1237 struct page *page;
1238 pgoff_t pgoff;
1239 void *kptr;
1240
1241 page = binder_alloc_get_page(alloc, buffer,
1242 buffer_offset, &pgoff);
1243 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1244 kptr = kmap_local_page(page) + pgoff;
1245 ret = copy_from_user(kptr, from, size);
1246 kunmap_local(kptr);
1247 if (ret)
1248 return bytes - size + ret;
1249 bytes -= size;
1250 from += size;
1251 buffer_offset += size;
1252 }
1253 return 0;
1254}
1255
1256static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1257 bool to_buffer,
1258 struct binder_buffer *buffer,
1259 binder_size_t buffer_offset,
1260 void *ptr,
1261 size_t bytes)
1262{
1263 /* All copies must be 32-bit aligned and 32-bit size */
1264 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1265 return -EINVAL;
1266
1267 while (bytes) {
1268 unsigned long size;
1269 struct page *page;
1270 pgoff_t pgoff;
1271
1272 page = binder_alloc_get_page(alloc, buffer,
1273 buffer_offset, &pgoff);
1274 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1275 if (to_buffer)
1276 memcpy_to_page(page, pgoff, ptr, size);
1277 else
1278 memcpy_from_page(ptr, page, pgoff, size);
1279 bytes -= size;
1280 pgoff = 0;
1281 ptr = ptr + size;
1282 buffer_offset += size;
1283 }
1284 return 0;
1285}
1286
1287int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1288 struct binder_buffer *buffer,
1289 binder_size_t buffer_offset,
1290 void *src,
1291 size_t bytes)
1292{
1293 return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1294 src, bytes);
1295}
1296
1297int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1298 void *dest,
1299 struct binder_buffer *buffer,
1300 binder_size_t buffer_offset,
1301 size_t bytes)
1302{
1303 return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
1304 dest, bytes);
1305}