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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_alloc_lru;
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 uintptr_t user_ptr)
129{
130 struct rb_node *n = alloc->allocated_buffers.rb_node;
131 struct binder_buffer *buffer;
132 void __user *uptr;
133
134 uptr = (void __user *)user_ptr;
135
136 while (n) {
137 buffer = rb_entry(n, struct binder_buffer, rb_node);
138 BUG_ON(buffer->free);
139
140 if (uptr < buffer->user_data)
141 n = n->rb_left;
142 else if (uptr > buffer->user_data)
143 n = n->rb_right;
144 else {
145 /*
146 * Guard against user threads attempting to
147 * free the buffer when in use by kernel or
148 * after it's already been freed.
149 */
150 if (!buffer->allow_user_free)
151 return ERR_PTR(-EPERM);
152 buffer->allow_user_free = 0;
153 return buffer;
154 }
155 }
156 return NULL;
157}
158
159/**
160 * binder_alloc_prepare_to_free() - get buffer given user ptr
161 * @alloc: binder_alloc for this proc
162 * @user_ptr: User pointer to buffer data
163 *
164 * Validate userspace pointer to buffer data and return buffer corresponding to
165 * that user pointer. Search the rb tree for buffer that matches user data
166 * pointer.
167 *
168 * Return: Pointer to buffer or NULL
169 */
170struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
171 uintptr_t user_ptr)
172{
173 struct binder_buffer *buffer;
174
175 mutex_lock(&alloc->mutex);
176 buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
177 mutex_unlock(&alloc->mutex);
178 return buffer;
179}
180
181static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
182 void __user *start, void __user *end)
183{
184 void __user *page_addr;
185 unsigned long user_page_addr;
186 struct binder_lru_page *page;
187 struct vm_area_struct *vma = NULL;
188 struct mm_struct *mm = NULL;
189 bool need_mm = false;
190
191 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
192 "%d: %s pages %pK-%pK\n", alloc->pid,
193 allocate ? "allocate" : "free", start, end);
194
195 if (end <= start)
196 return 0;
197
198 trace_binder_update_page_range(alloc, allocate, start, end);
199
200 if (allocate == 0)
201 goto free_range;
202
203 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
204 page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
205 if (!page->page_ptr) {
206 need_mm = true;
207 break;
208 }
209 }
210
211 if (need_mm && mmget_not_zero(alloc->vma_vm_mm))
212 mm = alloc->vma_vm_mm;
213
214 if (mm) {
215 mmap_read_lock(mm);
216 vma = alloc->vma;
217 }
218
219 if (!vma && need_mm) {
220 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
221 "%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
222 alloc->pid);
223 goto err_no_vma;
224 }
225
226 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
227 int ret;
228 bool on_lru;
229 size_t index;
230
231 index = (page_addr - alloc->buffer) / PAGE_SIZE;
232 page = &alloc->pages[index];
233
234 if (page->page_ptr) {
235 trace_binder_alloc_lru_start(alloc, index);
236
237 on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
238 WARN_ON(!on_lru);
239
240 trace_binder_alloc_lru_end(alloc, index);
241 continue;
242 }
243
244 if (WARN_ON(!vma))
245 goto err_page_ptr_cleared;
246
247 trace_binder_alloc_page_start(alloc, index);
248 page->page_ptr = alloc_page(GFP_KERNEL |
249 __GFP_HIGHMEM |
250 __GFP_ZERO);
251 if (!page->page_ptr) {
252 pr_err("%d: binder_alloc_buf failed for page at %pK\n",
253 alloc->pid, page_addr);
254 goto err_alloc_page_failed;
255 }
256 page->alloc = alloc;
257 INIT_LIST_HEAD(&page->lru);
258
259 user_page_addr = (uintptr_t)page_addr;
260 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
261 if (ret) {
262 pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
263 alloc->pid, user_page_addr);
264 goto err_vm_insert_page_failed;
265 }
266
267 if (index + 1 > alloc->pages_high)
268 alloc->pages_high = index + 1;
269
270 trace_binder_alloc_page_end(alloc, index);
271 }
272 if (mm) {
273 mmap_read_unlock(mm);
274 mmput(mm);
275 }
276 return 0;
277
278free_range:
279 for (page_addr = end - PAGE_SIZE; 1; page_addr -= PAGE_SIZE) {
280 bool ret;
281 size_t index;
282
283 index = (page_addr - alloc->buffer) / PAGE_SIZE;
284 page = &alloc->pages[index];
285
286 trace_binder_free_lru_start(alloc, index);
287
288 ret = list_lru_add(&binder_alloc_lru, &page->lru);
289 WARN_ON(!ret);
290
291 trace_binder_free_lru_end(alloc, index);
292 if (page_addr == start)
293 break;
294 continue;
295
296err_vm_insert_page_failed:
297 __free_page(page->page_ptr);
298 page->page_ptr = NULL;
299err_alloc_page_failed:
300err_page_ptr_cleared:
301 if (page_addr == start)
302 break;
303 }
304err_no_vma:
305 if (mm) {
306 mmap_read_unlock(mm);
307 mmput(mm);
308 }
309 return vma ? -ENOMEM : -ESRCH;
310}
311
312
313static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
314 struct vm_area_struct *vma)
315{
316 if (vma)
317 alloc->vma_vm_mm = vma->vm_mm;
318 /*
319 * If we see alloc->vma is not NULL, buffer data structures set up
320 * completely. Look at smp_rmb side binder_alloc_get_vma.
321 * We also want to guarantee new alloc->vma_vm_mm is always visible
322 * if alloc->vma is set.
323 */
324 smp_wmb();
325 alloc->vma = vma;
326}
327
328static inline struct vm_area_struct *binder_alloc_get_vma(
329 struct binder_alloc *alloc)
330{
331 struct vm_area_struct *vma = NULL;
332
333 if (alloc->vma) {
334 /* Look at description in binder_alloc_set_vma */
335 smp_rmb();
336 vma = alloc->vma;
337 }
338 return vma;
339}
340
341static struct binder_buffer *binder_alloc_new_buf_locked(
342 struct binder_alloc *alloc,
343 size_t data_size,
344 size_t offsets_size,
345 size_t extra_buffers_size,
346 int is_async)
347{
348 struct rb_node *n = alloc->free_buffers.rb_node;
349 struct binder_buffer *buffer;
350 size_t buffer_size;
351 struct rb_node *best_fit = NULL;
352 void __user *has_page_addr;
353 void __user *end_page_addr;
354 size_t size, data_offsets_size;
355 int ret;
356
357 if (!binder_alloc_get_vma(alloc)) {
358 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
359 "%d: binder_alloc_buf, no vma\n",
360 alloc->pid);
361 return ERR_PTR(-ESRCH);
362 }
363
364 data_offsets_size = ALIGN(data_size, sizeof(void *)) +
365 ALIGN(offsets_size, sizeof(void *));
366
367 if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
368 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
369 "%d: got transaction with invalid size %zd-%zd\n",
370 alloc->pid, data_size, offsets_size);
371 return ERR_PTR(-EINVAL);
372 }
373 size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
374 if (size < data_offsets_size || size < extra_buffers_size) {
375 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
376 "%d: got transaction with invalid extra_buffers_size %zd\n",
377 alloc->pid, extra_buffers_size);
378 return ERR_PTR(-EINVAL);
379 }
380 if (is_async &&
381 alloc->free_async_space < size + sizeof(struct binder_buffer)) {
382 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
383 "%d: binder_alloc_buf size %zd failed, no async space left\n",
384 alloc->pid, size);
385 return ERR_PTR(-ENOSPC);
386 }
387
388 /* Pad 0-size buffers so they get assigned unique addresses */
389 size = max(size, sizeof(void *));
390
391 while (n) {
392 buffer = rb_entry(n, struct binder_buffer, rb_node);
393 BUG_ON(!buffer->free);
394 buffer_size = binder_alloc_buffer_size(alloc, buffer);
395
396 if (size < buffer_size) {
397 best_fit = n;
398 n = n->rb_left;
399 } else if (size > buffer_size)
400 n = n->rb_right;
401 else {
402 best_fit = n;
403 break;
404 }
405 }
406 if (best_fit == NULL) {
407 size_t allocated_buffers = 0;
408 size_t largest_alloc_size = 0;
409 size_t total_alloc_size = 0;
410 size_t free_buffers = 0;
411 size_t largest_free_size = 0;
412 size_t total_free_size = 0;
413
414 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
415 n = rb_next(n)) {
416 buffer = rb_entry(n, struct binder_buffer, rb_node);
417 buffer_size = binder_alloc_buffer_size(alloc, buffer);
418 allocated_buffers++;
419 total_alloc_size += buffer_size;
420 if (buffer_size > largest_alloc_size)
421 largest_alloc_size = buffer_size;
422 }
423 for (n = rb_first(&alloc->free_buffers); n != NULL;
424 n = rb_next(n)) {
425 buffer = rb_entry(n, struct binder_buffer, rb_node);
426 buffer_size = binder_alloc_buffer_size(alloc, buffer);
427 free_buffers++;
428 total_free_size += buffer_size;
429 if (buffer_size > largest_free_size)
430 largest_free_size = buffer_size;
431 }
432 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
433 "%d: binder_alloc_buf size %zd failed, no address space\n",
434 alloc->pid, size);
435 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
436 "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
437 total_alloc_size, allocated_buffers,
438 largest_alloc_size, total_free_size,
439 free_buffers, largest_free_size);
440 return ERR_PTR(-ENOSPC);
441 }
442 if (n == NULL) {
443 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
444 buffer_size = binder_alloc_buffer_size(alloc, buffer);
445 }
446
447 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
448 "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
449 alloc->pid, size, buffer, buffer_size);
450
451 has_page_addr = (void __user *)
452 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
453 WARN_ON(n && buffer_size != size);
454 end_page_addr =
455 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
456 if (end_page_addr > has_page_addr)
457 end_page_addr = has_page_addr;
458 ret = binder_update_page_range(alloc, 1, (void __user *)
459 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
460 if (ret)
461 return ERR_PTR(ret);
462
463 if (buffer_size != size) {
464 struct binder_buffer *new_buffer;
465
466 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
467 if (!new_buffer) {
468 pr_err("%s: %d failed to alloc new buffer struct\n",
469 __func__, alloc->pid);
470 goto err_alloc_buf_struct_failed;
471 }
472 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
473 list_add(&new_buffer->entry, &buffer->entry);
474 new_buffer->free = 1;
475 binder_insert_free_buffer(alloc, new_buffer);
476 }
477
478 rb_erase(best_fit, &alloc->free_buffers);
479 buffer->free = 0;
480 buffer->allow_user_free = 0;
481 binder_insert_allocated_buffer_locked(alloc, buffer);
482 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
483 "%d: binder_alloc_buf size %zd got %pK\n",
484 alloc->pid, size, buffer);
485 buffer->data_size = data_size;
486 buffer->offsets_size = offsets_size;
487 buffer->async_transaction = is_async;
488 buffer->extra_buffers_size = extra_buffers_size;
489 if (is_async) {
490 alloc->free_async_space -= size + sizeof(struct binder_buffer);
491 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
492 "%d: binder_alloc_buf size %zd async free %zd\n",
493 alloc->pid, size, alloc->free_async_space);
494 }
495 return buffer;
496
497err_alloc_buf_struct_failed:
498 binder_update_page_range(alloc, 0, (void __user *)
499 PAGE_ALIGN((uintptr_t)buffer->user_data),
500 end_page_addr);
501 return ERR_PTR(-ENOMEM);
502}
503
504/**
505 * binder_alloc_new_buf() - Allocate a new binder buffer
506 * @alloc: binder_alloc for this proc
507 * @data_size: size of user data buffer
508 * @offsets_size: user specified buffer offset
509 * @extra_buffers_size: size of extra space for meta-data (eg, security context)
510 * @is_async: buffer for async transaction
511 *
512 * Allocate a new buffer given the requested sizes. Returns
513 * the kernel version of the buffer pointer. The size allocated
514 * is the sum of the three given sizes (each rounded up to
515 * pointer-sized boundary)
516 *
517 * Return: The allocated buffer or %NULL if error
518 */
519struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
520 size_t data_size,
521 size_t offsets_size,
522 size_t extra_buffers_size,
523 int is_async)
524{
525 struct binder_buffer *buffer;
526
527 mutex_lock(&alloc->mutex);
528 buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
529 extra_buffers_size, is_async);
530 mutex_unlock(&alloc->mutex);
531 return buffer;
532}
533
534static void __user *buffer_start_page(struct binder_buffer *buffer)
535{
536 return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
537}
538
539static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
540{
541 return (void __user *)
542 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
543}
544
545static void binder_delete_free_buffer(struct binder_alloc *alloc,
546 struct binder_buffer *buffer)
547{
548 struct binder_buffer *prev, *next = NULL;
549 bool to_free = true;
550
551 BUG_ON(alloc->buffers.next == &buffer->entry);
552 prev = binder_buffer_prev(buffer);
553 BUG_ON(!prev->free);
554 if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
555 to_free = false;
556 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
557 "%d: merge free, buffer %pK share page with %pK\n",
558 alloc->pid, buffer->user_data,
559 prev->user_data);
560 }
561
562 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
563 next = binder_buffer_next(buffer);
564 if (buffer_start_page(next) == buffer_start_page(buffer)) {
565 to_free = false;
566 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
567 "%d: merge free, buffer %pK share page with %pK\n",
568 alloc->pid,
569 buffer->user_data,
570 next->user_data);
571 }
572 }
573
574 if (PAGE_ALIGNED(buffer->user_data)) {
575 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
576 "%d: merge free, buffer start %pK is page aligned\n",
577 alloc->pid, buffer->user_data);
578 to_free = false;
579 }
580
581 if (to_free) {
582 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
583 "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
584 alloc->pid, buffer->user_data,
585 prev->user_data,
586 next ? next->user_data : NULL);
587 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
588 buffer_start_page(buffer) + PAGE_SIZE);
589 }
590 list_del(&buffer->entry);
591 kfree(buffer);
592}
593
594static void binder_free_buf_locked(struct binder_alloc *alloc,
595 struct binder_buffer *buffer)
596{
597 size_t size, buffer_size;
598
599 buffer_size = binder_alloc_buffer_size(alloc, buffer);
600
601 size = ALIGN(buffer->data_size, sizeof(void *)) +
602 ALIGN(buffer->offsets_size, sizeof(void *)) +
603 ALIGN(buffer->extra_buffers_size, sizeof(void *));
604
605 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
606 "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
607 alloc->pid, buffer, size, buffer_size);
608
609 BUG_ON(buffer->free);
610 BUG_ON(size > buffer_size);
611 BUG_ON(buffer->transaction != NULL);
612 BUG_ON(buffer->user_data < alloc->buffer);
613 BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
614
615 if (buffer->async_transaction) {
616 alloc->free_async_space += size + sizeof(struct binder_buffer);
617
618 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
619 "%d: binder_free_buf size %zd async free %zd\n",
620 alloc->pid, size, alloc->free_async_space);
621 }
622
623 binder_update_page_range(alloc, 0,
624 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
625 (void __user *)(((uintptr_t)
626 buffer->user_data + buffer_size) & PAGE_MASK));
627
628 rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
629 buffer->free = 1;
630 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
631 struct binder_buffer *next = binder_buffer_next(buffer);
632
633 if (next->free) {
634 rb_erase(&next->rb_node, &alloc->free_buffers);
635 binder_delete_free_buffer(alloc, next);
636 }
637 }
638 if (alloc->buffers.next != &buffer->entry) {
639 struct binder_buffer *prev = binder_buffer_prev(buffer);
640
641 if (prev->free) {
642 binder_delete_free_buffer(alloc, buffer);
643 rb_erase(&prev->rb_node, &alloc->free_buffers);
644 buffer = prev;
645 }
646 }
647 binder_insert_free_buffer(alloc, buffer);
648}
649
650/**
651 * binder_alloc_free_buf() - free a binder buffer
652 * @alloc: binder_alloc for this proc
653 * @buffer: kernel pointer to buffer
654 *
655 * Free the buffer allocated via binder_alloc_new_buffer()
656 */
657void binder_alloc_free_buf(struct binder_alloc *alloc,
658 struct binder_buffer *buffer)
659{
660 mutex_lock(&alloc->mutex);
661 binder_free_buf_locked(alloc, buffer);
662 mutex_unlock(&alloc->mutex);
663}
664
665/**
666 * binder_alloc_mmap_handler() - map virtual address space for proc
667 * @alloc: alloc structure for this proc
668 * @vma: vma passed to mmap()
669 *
670 * Called by binder_mmap() to initialize the space specified in
671 * vma for allocating binder buffers
672 *
673 * Return:
674 * 0 = success
675 * -EBUSY = address space already mapped
676 * -ENOMEM = failed to map memory to given address space
677 */
678int binder_alloc_mmap_handler(struct binder_alloc *alloc,
679 struct vm_area_struct *vma)
680{
681 int ret;
682 const char *failure_string;
683 struct binder_buffer *buffer;
684
685 mutex_lock(&binder_alloc_mmap_lock);
686 if (alloc->buffer_size) {
687 ret = -EBUSY;
688 failure_string = "already mapped";
689 goto err_already_mapped;
690 }
691 alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
692 SZ_4M);
693 mutex_unlock(&binder_alloc_mmap_lock);
694
695 alloc->buffer = (void __user *)vma->vm_start;
696
697 alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
698 sizeof(alloc->pages[0]),
699 GFP_KERNEL);
700 if (alloc->pages == NULL) {
701 ret = -ENOMEM;
702 failure_string = "alloc page array";
703 goto err_alloc_pages_failed;
704 }
705
706 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
707 if (!buffer) {
708 ret = -ENOMEM;
709 failure_string = "alloc buffer struct";
710 goto err_alloc_buf_struct_failed;
711 }
712
713 buffer->user_data = alloc->buffer;
714 list_add(&buffer->entry, &alloc->buffers);
715 buffer->free = 1;
716 binder_insert_free_buffer(alloc, buffer);
717 alloc->free_async_space = alloc->buffer_size / 2;
718 binder_alloc_set_vma(alloc, vma);
719 mmgrab(alloc->vma_vm_mm);
720
721 return 0;
722
723err_alloc_buf_struct_failed:
724 kfree(alloc->pages);
725 alloc->pages = NULL;
726err_alloc_pages_failed:
727 alloc->buffer = NULL;
728 mutex_lock(&binder_alloc_mmap_lock);
729 alloc->buffer_size = 0;
730err_already_mapped:
731 mutex_unlock(&binder_alloc_mmap_lock);
732 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
733 "%s: %d %lx-%lx %s failed %d\n", __func__,
734 alloc->pid, vma->vm_start, vma->vm_end,
735 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 buffers = 0;
747 mutex_lock(&alloc->mutex);
748 BUG_ON(alloc->vma);
749
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 __user *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 __free_page(alloc->pages[i].page_ptr);
789 page_count++;
790 }
791 kfree(alloc->pages);
792 }
793 mutex_unlock(&alloc->mutex);
794 if (alloc->vma_vm_mm)
795 mmdrop(alloc->vma_vm_mm);
796
797 binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
798 "%s: %d buffers %d, pages %d\n",
799 __func__, alloc->pid, buffers, page_count);
800}
801
802static void print_binder_buffer(struct seq_file *m, const char *prefix,
803 struct binder_buffer *buffer)
804{
805 seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
806 prefix, buffer->debug_id, buffer->user_data,
807 buffer->data_size, buffer->offsets_size,
808 buffer->extra_buffers_size,
809 buffer->transaction ? "active" : "delivered");
810}
811
812/**
813 * binder_alloc_print_allocated() - print buffer info
814 * @m: seq_file for output via seq_printf()
815 * @alloc: binder_alloc for this proc
816 *
817 * Prints information about every buffer associated with
818 * the binder_alloc state to the given seq_file
819 */
820void binder_alloc_print_allocated(struct seq_file *m,
821 struct binder_alloc *alloc)
822{
823 struct rb_node *n;
824
825 mutex_lock(&alloc->mutex);
826 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
827 print_binder_buffer(m, " buffer",
828 rb_entry(n, struct binder_buffer, rb_node));
829 mutex_unlock(&alloc->mutex);
830}
831
832/**
833 * binder_alloc_print_pages() - print page usage
834 * @m: seq_file for output via seq_printf()
835 * @alloc: binder_alloc for this proc
836 */
837void binder_alloc_print_pages(struct seq_file *m,
838 struct binder_alloc *alloc)
839{
840 struct binder_lru_page *page;
841 int i;
842 int active = 0;
843 int lru = 0;
844 int free = 0;
845
846 mutex_lock(&alloc->mutex);
847 /*
848 * Make sure the binder_alloc is fully initialized, otherwise we might
849 * read inconsistent state.
850 */
851 if (binder_alloc_get_vma(alloc) != NULL) {
852 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
853 page = &alloc->pages[i];
854 if (!page->page_ptr)
855 free++;
856 else if (list_empty(&page->lru))
857 active++;
858 else
859 lru++;
860 }
861 }
862 mutex_unlock(&alloc->mutex);
863 seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
864 seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);
865}
866
867/**
868 * binder_alloc_get_allocated_count() - return count of buffers
869 * @alloc: binder_alloc for this proc
870 *
871 * Return: count of allocated buffers
872 */
873int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
874{
875 struct rb_node *n;
876 int count = 0;
877
878 mutex_lock(&alloc->mutex);
879 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
880 count++;
881 mutex_unlock(&alloc->mutex);
882 return count;
883}
884
885
886/**
887 * binder_alloc_vma_close() - invalidate address space
888 * @alloc: binder_alloc for this proc
889 *
890 * Called from binder_vma_close() when releasing address space.
891 * Clears alloc->vma to prevent new incoming transactions from
892 * allocating more buffers.
893 */
894void binder_alloc_vma_close(struct binder_alloc *alloc)
895{
896 binder_alloc_set_vma(alloc, NULL);
897}
898
899/**
900 * binder_alloc_free_page() - shrinker callback to free pages
901 * @item: item to free
902 * @lock: lock protecting the item
903 * @cb_arg: callback argument
904 *
905 * Called from list_lru_walk() in binder_shrink_scan() to free
906 * up pages when the system is under memory pressure.
907 */
908enum lru_status binder_alloc_free_page(struct list_head *item,
909 struct list_lru_one *lru,
910 spinlock_t *lock,
911 void *cb_arg)
912 __must_hold(lock)
913{
914 struct mm_struct *mm = NULL;
915 struct binder_lru_page *page = container_of(item,
916 struct binder_lru_page,
917 lru);
918 struct binder_alloc *alloc;
919 uintptr_t page_addr;
920 size_t index;
921 struct vm_area_struct *vma;
922
923 alloc = page->alloc;
924 if (!mutex_trylock(&alloc->mutex))
925 goto err_get_alloc_mutex_failed;
926
927 if (!page->page_ptr)
928 goto err_page_already_freed;
929
930 index = page - alloc->pages;
931 page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
932
933 mm = alloc->vma_vm_mm;
934 if (!mmget_not_zero(mm))
935 goto err_mmget;
936 if (!mmap_read_trylock(mm))
937 goto err_mmap_read_lock_failed;
938 vma = binder_alloc_get_vma(alloc);
939
940 list_lru_isolate(lru, item);
941 spin_unlock(lock);
942
943 if (vma) {
944 trace_binder_unmap_user_start(alloc, index);
945
946 zap_page_range(vma, page_addr, PAGE_SIZE);
947
948 trace_binder_unmap_user_end(alloc, index);
949 }
950 mmap_read_unlock(mm);
951 mmput_async(mm);
952
953 trace_binder_unmap_kernel_start(alloc, index);
954
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_mmap_read_lock_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}
1021
1022/**
1023 * check_buffer() - verify that buffer/offset is safe to access
1024 * @alloc: binder_alloc for this proc
1025 * @buffer: binder buffer to be accessed
1026 * @offset: offset into @buffer data
1027 * @bytes: bytes to access from offset
1028 *
1029 * Check that the @offset/@bytes are within the size of the given
1030 * @buffer and that the buffer is currently active and not freeable.
1031 * Offsets must also be multiples of sizeof(u32). The kernel is
1032 * allowed to touch the buffer in two cases:
1033 *
1034 * 1) when the buffer is being created:
1035 * (buffer->free == 0 && buffer->allow_user_free == 0)
1036 * 2) when the buffer is being torn down:
1037 * (buffer->free == 0 && buffer->transaction == NULL).
1038 *
1039 * Return: true if the buffer is safe to access
1040 */
1041static inline bool check_buffer(struct binder_alloc *alloc,
1042 struct binder_buffer *buffer,
1043 binder_size_t offset, size_t bytes)
1044{
1045 size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1046
1047 return buffer_size >= bytes &&
1048 offset <= buffer_size - bytes &&
1049 IS_ALIGNED(offset, sizeof(u32)) &&
1050 !buffer->free &&
1051 (!buffer->allow_user_free || !buffer->transaction);
1052}
1053
1054/**
1055 * binder_alloc_get_page() - get kernel pointer for given buffer offset
1056 * @alloc: binder_alloc for this proc
1057 * @buffer: binder buffer to be accessed
1058 * @buffer_offset: offset into @buffer data
1059 * @pgoffp: address to copy final page offset to
1060 *
1061 * Lookup the struct page corresponding to the address
1062 * at @buffer_offset into @buffer->user_data. If @pgoffp is not
1063 * NULL, the byte-offset into the page is written there.
1064 *
1065 * The caller is responsible to ensure that the offset points
1066 * to a valid address within the @buffer and that @buffer is
1067 * not freeable by the user. Since it can't be freed, we are
1068 * guaranteed that the corresponding elements of @alloc->pages[]
1069 * cannot change.
1070 *
1071 * Return: struct page
1072 */
1073static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1074 struct binder_buffer *buffer,
1075 binder_size_t buffer_offset,
1076 pgoff_t *pgoffp)
1077{
1078 binder_size_t buffer_space_offset = buffer_offset +
1079 (buffer->user_data - alloc->buffer);
1080 pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
1081 size_t index = buffer_space_offset >> PAGE_SHIFT;
1082 struct binder_lru_page *lru_page;
1083
1084 lru_page = &alloc->pages[index];
1085 *pgoffp = pgoff;
1086 return lru_page->page_ptr;
1087}
1088
1089/**
1090 * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1091 * @alloc: binder_alloc for this proc
1092 * @buffer: binder buffer to be accessed
1093 * @buffer_offset: offset into @buffer data
1094 * @from: userspace pointer to source buffer
1095 * @bytes: bytes to copy
1096 *
1097 * Copy bytes from source userspace to target buffer.
1098 *
1099 * Return: bytes remaining to be copied
1100 */
1101unsigned long
1102binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1103 struct binder_buffer *buffer,
1104 binder_size_t buffer_offset,
1105 const void __user *from,
1106 size_t bytes)
1107{
1108 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1109 return bytes;
1110
1111 while (bytes) {
1112 unsigned long size;
1113 unsigned long ret;
1114 struct page *page;
1115 pgoff_t pgoff;
1116 void *kptr;
1117
1118 page = binder_alloc_get_page(alloc, buffer,
1119 buffer_offset, &pgoff);
1120 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1121 kptr = kmap(page) + pgoff;
1122 ret = copy_from_user(kptr, from, size);
1123 kunmap(page);
1124 if (ret)
1125 return bytes - size + ret;
1126 bytes -= size;
1127 from += size;
1128 buffer_offset += size;
1129 }
1130 return 0;
1131}
1132
1133static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1134 bool to_buffer,
1135 struct binder_buffer *buffer,
1136 binder_size_t buffer_offset,
1137 void *ptr,
1138 size_t bytes)
1139{
1140 /* All copies must be 32-bit aligned and 32-bit size */
1141 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1142 return -EINVAL;
1143
1144 while (bytes) {
1145 unsigned long size;
1146 struct page *page;
1147 pgoff_t pgoff;
1148 void *tmpptr;
1149 void *base_ptr;
1150
1151 page = binder_alloc_get_page(alloc, buffer,
1152 buffer_offset, &pgoff);
1153 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1154 base_ptr = kmap_atomic(page);
1155 tmpptr = base_ptr + pgoff;
1156 if (to_buffer)
1157 memcpy(tmpptr, ptr, size);
1158 else
1159 memcpy(ptr, tmpptr, size);
1160 /*
1161 * kunmap_atomic() takes care of flushing the cache
1162 * if this device has VIVT cache arch
1163 */
1164 kunmap_atomic(base_ptr);
1165 bytes -= size;
1166 pgoff = 0;
1167 ptr = ptr + size;
1168 buffer_offset += size;
1169 }
1170 return 0;
1171}
1172
1173int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1174 struct binder_buffer *buffer,
1175 binder_size_t buffer_offset,
1176 void *src,
1177 size_t bytes)
1178{
1179 return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1180 src, bytes);
1181}
1182
1183int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1184 void *dest,
1185 struct binder_buffer *buffer,
1186 binder_size_t buffer_offset,
1187 size_t bytes)
1188{
1189 return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
1190 dest, bytes);
1191}
1192