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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
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 bool debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
342{
343 /*
344 * Find the amount and size of buffers allocated by the current caller;
345 * The idea is that once we cross the threshold, whoever is responsible
346 * for the low async space is likely to try to send another async txn,
347 * and at some point we'll catch them in the act. This is more efficient
348 * than keeping a map per pid.
349 */
350 struct rb_node *n;
351 struct binder_buffer *buffer;
352 size_t total_alloc_size = 0;
353 size_t num_buffers = 0;
354
355 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
356 n = rb_next(n)) {
357 buffer = rb_entry(n, struct binder_buffer, rb_node);
358 if (buffer->pid != pid)
359 continue;
360 if (!buffer->async_transaction)
361 continue;
362 total_alloc_size += binder_alloc_buffer_size(alloc, buffer)
363 + sizeof(struct binder_buffer);
364 num_buffers++;
365 }
366
367 /*
368 * Warn if this pid has more than 50 transactions, or more than 50% of
369 * async space (which is 25% of total buffer size). Oneway spam is only
370 * detected when the threshold is exceeded.
371 */
372 if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) {
373 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
374 "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n",
375 alloc->pid, pid, num_buffers, total_alloc_size);
376 if (!alloc->oneway_spam_detected) {
377 alloc->oneway_spam_detected = true;
378 return true;
379 }
380 }
381 return false;
382}
383
384static struct binder_buffer *binder_alloc_new_buf_locked(
385 struct binder_alloc *alloc,
386 size_t data_size,
387 size_t offsets_size,
388 size_t extra_buffers_size,
389 int is_async,
390 int pid)
391{
392 struct rb_node *n = alloc->free_buffers.rb_node;
393 struct binder_buffer *buffer;
394 size_t buffer_size;
395 struct rb_node *best_fit = NULL;
396 void __user *has_page_addr;
397 void __user *end_page_addr;
398 size_t size, data_offsets_size;
399 int ret;
400
401 if (!binder_alloc_get_vma(alloc)) {
402 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
403 "%d: binder_alloc_buf, no vma\n",
404 alloc->pid);
405 return ERR_PTR(-ESRCH);
406 }
407
408 data_offsets_size = ALIGN(data_size, sizeof(void *)) +
409 ALIGN(offsets_size, sizeof(void *));
410
411 if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
412 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
413 "%d: got transaction with invalid size %zd-%zd\n",
414 alloc->pid, data_size, offsets_size);
415 return ERR_PTR(-EINVAL);
416 }
417 size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
418 if (size < data_offsets_size || size < extra_buffers_size) {
419 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
420 "%d: got transaction with invalid extra_buffers_size %zd\n",
421 alloc->pid, extra_buffers_size);
422 return ERR_PTR(-EINVAL);
423 }
424 if (is_async &&
425 alloc->free_async_space < size + sizeof(struct binder_buffer)) {
426 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
427 "%d: binder_alloc_buf size %zd failed, no async space left\n",
428 alloc->pid, size);
429 return ERR_PTR(-ENOSPC);
430 }
431
432 /* Pad 0-size buffers so they get assigned unique addresses */
433 size = max(size, sizeof(void *));
434
435 while (n) {
436 buffer = rb_entry(n, struct binder_buffer, rb_node);
437 BUG_ON(!buffer->free);
438 buffer_size = binder_alloc_buffer_size(alloc, buffer);
439
440 if (size < buffer_size) {
441 best_fit = n;
442 n = n->rb_left;
443 } else if (size > buffer_size)
444 n = n->rb_right;
445 else {
446 best_fit = n;
447 break;
448 }
449 }
450 if (best_fit == NULL) {
451 size_t allocated_buffers = 0;
452 size_t largest_alloc_size = 0;
453 size_t total_alloc_size = 0;
454 size_t free_buffers = 0;
455 size_t largest_free_size = 0;
456 size_t total_free_size = 0;
457
458 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
459 n = rb_next(n)) {
460 buffer = rb_entry(n, struct binder_buffer, rb_node);
461 buffer_size = binder_alloc_buffer_size(alloc, buffer);
462 allocated_buffers++;
463 total_alloc_size += buffer_size;
464 if (buffer_size > largest_alloc_size)
465 largest_alloc_size = buffer_size;
466 }
467 for (n = rb_first(&alloc->free_buffers); n != NULL;
468 n = rb_next(n)) {
469 buffer = rb_entry(n, struct binder_buffer, rb_node);
470 buffer_size = binder_alloc_buffer_size(alloc, buffer);
471 free_buffers++;
472 total_free_size += buffer_size;
473 if (buffer_size > largest_free_size)
474 largest_free_size = buffer_size;
475 }
476 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
477 "%d: binder_alloc_buf size %zd failed, no address space\n",
478 alloc->pid, size);
479 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
480 "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
481 total_alloc_size, allocated_buffers,
482 largest_alloc_size, total_free_size,
483 free_buffers, largest_free_size);
484 return ERR_PTR(-ENOSPC);
485 }
486 if (n == NULL) {
487 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
488 buffer_size = binder_alloc_buffer_size(alloc, buffer);
489 }
490
491 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
492 "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
493 alloc->pid, size, buffer, buffer_size);
494
495 has_page_addr = (void __user *)
496 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
497 WARN_ON(n && buffer_size != size);
498 end_page_addr =
499 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
500 if (end_page_addr > has_page_addr)
501 end_page_addr = has_page_addr;
502 ret = binder_update_page_range(alloc, 1, (void __user *)
503 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
504 if (ret)
505 return ERR_PTR(ret);
506
507 if (buffer_size != size) {
508 struct binder_buffer *new_buffer;
509
510 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
511 if (!new_buffer) {
512 pr_err("%s: %d failed to alloc new buffer struct\n",
513 __func__, alloc->pid);
514 goto err_alloc_buf_struct_failed;
515 }
516 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
517 list_add(&new_buffer->entry, &buffer->entry);
518 new_buffer->free = 1;
519 binder_insert_free_buffer(alloc, new_buffer);
520 }
521
522 rb_erase(best_fit, &alloc->free_buffers);
523 buffer->free = 0;
524 buffer->allow_user_free = 0;
525 binder_insert_allocated_buffer_locked(alloc, buffer);
526 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
527 "%d: binder_alloc_buf size %zd got %pK\n",
528 alloc->pid, size, buffer);
529 buffer->data_size = data_size;
530 buffer->offsets_size = offsets_size;
531 buffer->async_transaction = is_async;
532 buffer->extra_buffers_size = extra_buffers_size;
533 buffer->pid = pid;
534 buffer->oneway_spam_suspect = false;
535 if (is_async) {
536 alloc->free_async_space -= size + sizeof(struct binder_buffer);
537 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
538 "%d: binder_alloc_buf size %zd async free %zd\n",
539 alloc->pid, size, alloc->free_async_space);
540 if (alloc->free_async_space < alloc->buffer_size / 10) {
541 /*
542 * Start detecting spammers once we have less than 20%
543 * of async space left (which is less than 10% of total
544 * buffer size).
545 */
546 buffer->oneway_spam_suspect = debug_low_async_space_locked(alloc, pid);
547 } else {
548 alloc->oneway_spam_detected = false;
549 }
550 }
551 return buffer;
552
553err_alloc_buf_struct_failed:
554 binder_update_page_range(alloc, 0, (void __user *)
555 PAGE_ALIGN((uintptr_t)buffer->user_data),
556 end_page_addr);
557 return ERR_PTR(-ENOMEM);
558}
559
560/**
561 * binder_alloc_new_buf() - Allocate a new binder buffer
562 * @alloc: binder_alloc for this proc
563 * @data_size: size of user data buffer
564 * @offsets_size: user specified buffer offset
565 * @extra_buffers_size: size of extra space for meta-data (eg, security context)
566 * @is_async: buffer for async transaction
567 * @pid: pid to attribute allocation to (used for debugging)
568 *
569 * Allocate a new buffer given the requested sizes. Returns
570 * the kernel version of the buffer pointer. The size allocated
571 * is the sum of the three given sizes (each rounded up to
572 * pointer-sized boundary)
573 *
574 * Return: The allocated buffer or %NULL if error
575 */
576struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
577 size_t data_size,
578 size_t offsets_size,
579 size_t extra_buffers_size,
580 int is_async,
581 int pid)
582{
583 struct binder_buffer *buffer;
584
585 mutex_lock(&alloc->mutex);
586 buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
587 extra_buffers_size, is_async, pid);
588 mutex_unlock(&alloc->mutex);
589 return buffer;
590}
591
592static void __user *buffer_start_page(struct binder_buffer *buffer)
593{
594 return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
595}
596
597static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
598{
599 return (void __user *)
600 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
601}
602
603static void binder_delete_free_buffer(struct binder_alloc *alloc,
604 struct binder_buffer *buffer)
605{
606 struct binder_buffer *prev, *next = NULL;
607 bool to_free = true;
608
609 BUG_ON(alloc->buffers.next == &buffer->entry);
610 prev = binder_buffer_prev(buffer);
611 BUG_ON(!prev->free);
612 if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
613 to_free = false;
614 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
615 "%d: merge free, buffer %pK share page with %pK\n",
616 alloc->pid, buffer->user_data,
617 prev->user_data);
618 }
619
620 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
621 next = binder_buffer_next(buffer);
622 if (buffer_start_page(next) == buffer_start_page(buffer)) {
623 to_free = false;
624 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
625 "%d: merge free, buffer %pK share page with %pK\n",
626 alloc->pid,
627 buffer->user_data,
628 next->user_data);
629 }
630 }
631
632 if (PAGE_ALIGNED(buffer->user_data)) {
633 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
634 "%d: merge free, buffer start %pK is page aligned\n",
635 alloc->pid, buffer->user_data);
636 to_free = false;
637 }
638
639 if (to_free) {
640 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
641 "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
642 alloc->pid, buffer->user_data,
643 prev->user_data,
644 next ? next->user_data : NULL);
645 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
646 buffer_start_page(buffer) + PAGE_SIZE);
647 }
648 list_del(&buffer->entry);
649 kfree(buffer);
650}
651
652static void binder_free_buf_locked(struct binder_alloc *alloc,
653 struct binder_buffer *buffer)
654{
655 size_t size, buffer_size;
656
657 buffer_size = binder_alloc_buffer_size(alloc, buffer);
658
659 size = ALIGN(buffer->data_size, sizeof(void *)) +
660 ALIGN(buffer->offsets_size, sizeof(void *)) +
661 ALIGN(buffer->extra_buffers_size, sizeof(void *));
662
663 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
664 "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
665 alloc->pid, buffer, size, buffer_size);
666
667 BUG_ON(buffer->free);
668 BUG_ON(size > buffer_size);
669 BUG_ON(buffer->transaction != NULL);
670 BUG_ON(buffer->user_data < alloc->buffer);
671 BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
672
673 if (buffer->async_transaction) {
674 alloc->free_async_space += size + sizeof(struct binder_buffer);
675
676 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
677 "%d: binder_free_buf size %zd async free %zd\n",
678 alloc->pid, size, alloc->free_async_space);
679 }
680
681 binder_update_page_range(alloc, 0,
682 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
683 (void __user *)(((uintptr_t)
684 buffer->user_data + buffer_size) & PAGE_MASK));
685
686 rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
687 buffer->free = 1;
688 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
689 struct binder_buffer *next = binder_buffer_next(buffer);
690
691 if (next->free) {
692 rb_erase(&next->rb_node, &alloc->free_buffers);
693 binder_delete_free_buffer(alloc, next);
694 }
695 }
696 if (alloc->buffers.next != &buffer->entry) {
697 struct binder_buffer *prev = binder_buffer_prev(buffer);
698
699 if (prev->free) {
700 binder_delete_free_buffer(alloc, buffer);
701 rb_erase(&prev->rb_node, &alloc->free_buffers);
702 buffer = prev;
703 }
704 }
705 binder_insert_free_buffer(alloc, buffer);
706}
707
708static void binder_alloc_clear_buf(struct binder_alloc *alloc,
709 struct binder_buffer *buffer);
710/**
711 * binder_alloc_free_buf() - free a binder buffer
712 * @alloc: binder_alloc for this proc
713 * @buffer: kernel pointer to buffer
714 *
715 * Free the buffer allocated via binder_alloc_new_buf()
716 */
717void binder_alloc_free_buf(struct binder_alloc *alloc,
718 struct binder_buffer *buffer)
719{
720 /*
721 * We could eliminate the call to binder_alloc_clear_buf()
722 * from binder_alloc_deferred_release() by moving this to
723 * binder_alloc_free_buf_locked(). However, that could
724 * increase contention for the alloc mutex if clear_on_free
725 * is used frequently for large buffers. The mutex is not
726 * needed for correctness here.
727 */
728 if (buffer->clear_on_free) {
729 binder_alloc_clear_buf(alloc, buffer);
730 buffer->clear_on_free = false;
731 }
732 mutex_lock(&alloc->mutex);
733 binder_free_buf_locked(alloc, buffer);
734 mutex_unlock(&alloc->mutex);
735}
736
737/**
738 * binder_alloc_mmap_handler() - map virtual address space for proc
739 * @alloc: alloc structure for this proc
740 * @vma: vma passed to mmap()
741 *
742 * Called by binder_mmap() to initialize the space specified in
743 * vma for allocating binder buffers
744 *
745 * Return:
746 * 0 = success
747 * -EBUSY = address space already mapped
748 * -ENOMEM = failed to map memory to given address space
749 */
750int binder_alloc_mmap_handler(struct binder_alloc *alloc,
751 struct vm_area_struct *vma)
752{
753 int ret;
754 const char *failure_string;
755 struct binder_buffer *buffer;
756
757 mutex_lock(&binder_alloc_mmap_lock);
758 if (alloc->buffer_size) {
759 ret = -EBUSY;
760 failure_string = "already mapped";
761 goto err_already_mapped;
762 }
763 alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
764 SZ_4M);
765 mutex_unlock(&binder_alloc_mmap_lock);
766
767 alloc->buffer = (void __user *)vma->vm_start;
768
769 alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
770 sizeof(alloc->pages[0]),
771 GFP_KERNEL);
772 if (alloc->pages == NULL) {
773 ret = -ENOMEM;
774 failure_string = "alloc page array";
775 goto err_alloc_pages_failed;
776 }
777
778 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
779 if (!buffer) {
780 ret = -ENOMEM;
781 failure_string = "alloc buffer struct";
782 goto err_alloc_buf_struct_failed;
783 }
784
785 buffer->user_data = alloc->buffer;
786 list_add(&buffer->entry, &alloc->buffers);
787 buffer->free = 1;
788 binder_insert_free_buffer(alloc, buffer);
789 alloc->free_async_space = alloc->buffer_size / 2;
790 binder_alloc_set_vma(alloc, vma);
791 mmgrab(alloc->vma_vm_mm);
792
793 return 0;
794
795err_alloc_buf_struct_failed:
796 kfree(alloc->pages);
797 alloc->pages = NULL;
798err_alloc_pages_failed:
799 alloc->buffer = NULL;
800 mutex_lock(&binder_alloc_mmap_lock);
801 alloc->buffer_size = 0;
802err_already_mapped:
803 mutex_unlock(&binder_alloc_mmap_lock);
804 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
805 "%s: %d %lx-%lx %s failed %d\n", __func__,
806 alloc->pid, vma->vm_start, vma->vm_end,
807 failure_string, ret);
808 return ret;
809}
810
811
812void binder_alloc_deferred_release(struct binder_alloc *alloc)
813{
814 struct rb_node *n;
815 int buffers, page_count;
816 struct binder_buffer *buffer;
817
818 buffers = 0;
819 mutex_lock(&alloc->mutex);
820 BUG_ON(alloc->vma);
821
822 while ((n = rb_first(&alloc->allocated_buffers))) {
823 buffer = rb_entry(n, struct binder_buffer, rb_node);
824
825 /* Transaction should already have been freed */
826 BUG_ON(buffer->transaction);
827
828 if (buffer->clear_on_free) {
829 binder_alloc_clear_buf(alloc, buffer);
830 buffer->clear_on_free = false;
831 }
832 binder_free_buf_locked(alloc, buffer);
833 buffers++;
834 }
835
836 while (!list_empty(&alloc->buffers)) {
837 buffer = list_first_entry(&alloc->buffers,
838 struct binder_buffer, entry);
839 WARN_ON(!buffer->free);
840
841 list_del(&buffer->entry);
842 WARN_ON_ONCE(!list_empty(&alloc->buffers));
843 kfree(buffer);
844 }
845
846 page_count = 0;
847 if (alloc->pages) {
848 int i;
849
850 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
851 void __user *page_addr;
852 bool on_lru;
853
854 if (!alloc->pages[i].page_ptr)
855 continue;
856
857 on_lru = list_lru_del(&binder_alloc_lru,
858 &alloc->pages[i].lru);
859 page_addr = alloc->buffer + i * PAGE_SIZE;
860 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
861 "%s: %d: page %d at %pK %s\n",
862 __func__, alloc->pid, i, page_addr,
863 on_lru ? "on lru" : "active");
864 __free_page(alloc->pages[i].page_ptr);
865 page_count++;
866 }
867 kfree(alloc->pages);
868 }
869 mutex_unlock(&alloc->mutex);
870 if (alloc->vma_vm_mm)
871 mmdrop(alloc->vma_vm_mm);
872
873 binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
874 "%s: %d buffers %d, pages %d\n",
875 __func__, alloc->pid, buffers, page_count);
876}
877
878static void print_binder_buffer(struct seq_file *m, const char *prefix,
879 struct binder_buffer *buffer)
880{
881 seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
882 prefix, buffer->debug_id, buffer->user_data,
883 buffer->data_size, buffer->offsets_size,
884 buffer->extra_buffers_size,
885 buffer->transaction ? "active" : "delivered");
886}
887
888/**
889 * binder_alloc_print_allocated() - print buffer info
890 * @m: seq_file for output via seq_printf()
891 * @alloc: binder_alloc for this proc
892 *
893 * Prints information about every buffer associated with
894 * the binder_alloc state to the given seq_file
895 */
896void binder_alloc_print_allocated(struct seq_file *m,
897 struct binder_alloc *alloc)
898{
899 struct rb_node *n;
900
901 mutex_lock(&alloc->mutex);
902 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
903 print_binder_buffer(m, " buffer",
904 rb_entry(n, struct binder_buffer, rb_node));
905 mutex_unlock(&alloc->mutex);
906}
907
908/**
909 * binder_alloc_print_pages() - print page usage
910 * @m: seq_file for output via seq_printf()
911 * @alloc: binder_alloc for this proc
912 */
913void binder_alloc_print_pages(struct seq_file *m,
914 struct binder_alloc *alloc)
915{
916 struct binder_lru_page *page;
917 int i;
918 int active = 0;
919 int lru = 0;
920 int free = 0;
921
922 mutex_lock(&alloc->mutex);
923 /*
924 * Make sure the binder_alloc is fully initialized, otherwise we might
925 * read inconsistent state.
926 */
927 if (binder_alloc_get_vma(alloc) != NULL) {
928 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
929 page = &alloc->pages[i];
930 if (!page->page_ptr)
931 free++;
932 else if (list_empty(&page->lru))
933 active++;
934 else
935 lru++;
936 }
937 }
938 mutex_unlock(&alloc->mutex);
939 seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
940 seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);
941}
942
943/**
944 * binder_alloc_get_allocated_count() - return count of buffers
945 * @alloc: binder_alloc for this proc
946 *
947 * Return: count of allocated buffers
948 */
949int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
950{
951 struct rb_node *n;
952 int count = 0;
953
954 mutex_lock(&alloc->mutex);
955 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
956 count++;
957 mutex_unlock(&alloc->mutex);
958 return count;
959}
960
961
962/**
963 * binder_alloc_vma_close() - invalidate address space
964 * @alloc: binder_alloc for this proc
965 *
966 * Called from binder_vma_close() when releasing address space.
967 * Clears alloc->vma to prevent new incoming transactions from
968 * allocating more buffers.
969 */
970void binder_alloc_vma_close(struct binder_alloc *alloc)
971{
972 binder_alloc_set_vma(alloc, NULL);
973}
974
975/**
976 * binder_alloc_free_page() - shrinker callback to free pages
977 * @item: item to free
978 * @lock: lock protecting the item
979 * @cb_arg: callback argument
980 *
981 * Called from list_lru_walk() in binder_shrink_scan() to free
982 * up pages when the system is under memory pressure.
983 */
984enum lru_status binder_alloc_free_page(struct list_head *item,
985 struct list_lru_one *lru,
986 spinlock_t *lock,
987 void *cb_arg)
988 __must_hold(lock)
989{
990 struct mm_struct *mm = NULL;
991 struct binder_lru_page *page = container_of(item,
992 struct binder_lru_page,
993 lru);
994 struct binder_alloc *alloc;
995 uintptr_t page_addr;
996 size_t index;
997 struct vm_area_struct *vma;
998
999 alloc = page->alloc;
1000 if (!mutex_trylock(&alloc->mutex))
1001 goto err_get_alloc_mutex_failed;
1002
1003 if (!page->page_ptr)
1004 goto err_page_already_freed;
1005
1006 index = page - alloc->pages;
1007 page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
1008
1009 mm = alloc->vma_vm_mm;
1010 if (!mmget_not_zero(mm))
1011 goto err_mmget;
1012 if (!mmap_read_trylock(mm))
1013 goto err_mmap_read_lock_failed;
1014 vma = binder_alloc_get_vma(alloc);
1015
1016 list_lru_isolate(lru, item);
1017 spin_unlock(lock);
1018
1019 if (vma) {
1020 trace_binder_unmap_user_start(alloc, index);
1021
1022 zap_page_range(vma, page_addr, PAGE_SIZE);
1023
1024 trace_binder_unmap_user_end(alloc, index);
1025 }
1026 mmap_read_unlock(mm);
1027 mmput_async(mm);
1028
1029 trace_binder_unmap_kernel_start(alloc, index);
1030
1031 __free_page(page->page_ptr);
1032 page->page_ptr = NULL;
1033
1034 trace_binder_unmap_kernel_end(alloc, index);
1035
1036 spin_lock(lock);
1037 mutex_unlock(&alloc->mutex);
1038 return LRU_REMOVED_RETRY;
1039
1040err_mmap_read_lock_failed:
1041 mmput_async(mm);
1042err_mmget:
1043err_page_already_freed:
1044 mutex_unlock(&alloc->mutex);
1045err_get_alloc_mutex_failed:
1046 return LRU_SKIP;
1047}
1048
1049static unsigned long
1050binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
1051{
1052 unsigned long ret = list_lru_count(&binder_alloc_lru);
1053 return ret;
1054}
1055
1056static unsigned long
1057binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1058{
1059 unsigned long ret;
1060
1061 ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
1062 NULL, sc->nr_to_scan);
1063 return ret;
1064}
1065
1066static struct shrinker binder_shrinker = {
1067 .count_objects = binder_shrink_count,
1068 .scan_objects = binder_shrink_scan,
1069 .seeks = DEFAULT_SEEKS,
1070};
1071
1072/**
1073 * binder_alloc_init() - called by binder_open() for per-proc initialization
1074 * @alloc: binder_alloc for this proc
1075 *
1076 * Called from binder_open() to initialize binder_alloc fields for
1077 * new binder proc
1078 */
1079void binder_alloc_init(struct binder_alloc *alloc)
1080{
1081 alloc->pid = current->group_leader->pid;
1082 mutex_init(&alloc->mutex);
1083 INIT_LIST_HEAD(&alloc->buffers);
1084}
1085
1086int binder_alloc_shrinker_init(void)
1087{
1088 int ret = list_lru_init(&binder_alloc_lru);
1089
1090 if (ret == 0) {
1091 ret = register_shrinker(&binder_shrinker);
1092 if (ret)
1093 list_lru_destroy(&binder_alloc_lru);
1094 }
1095 return ret;
1096}
1097
1098/**
1099 * check_buffer() - verify that buffer/offset is safe to access
1100 * @alloc: binder_alloc for this proc
1101 * @buffer: binder buffer to be accessed
1102 * @offset: offset into @buffer data
1103 * @bytes: bytes to access from offset
1104 *
1105 * Check that the @offset/@bytes are within the size of the given
1106 * @buffer and that the buffer is currently active and not freeable.
1107 * Offsets must also be multiples of sizeof(u32). The kernel is
1108 * allowed to touch the buffer in two cases:
1109 *
1110 * 1) when the buffer is being created:
1111 * (buffer->free == 0 && buffer->allow_user_free == 0)
1112 * 2) when the buffer is being torn down:
1113 * (buffer->free == 0 && buffer->transaction == NULL).
1114 *
1115 * Return: true if the buffer is safe to access
1116 */
1117static inline bool check_buffer(struct binder_alloc *alloc,
1118 struct binder_buffer *buffer,
1119 binder_size_t offset, size_t bytes)
1120{
1121 size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1122
1123 return buffer_size >= bytes &&
1124 offset <= buffer_size - bytes &&
1125 IS_ALIGNED(offset, sizeof(u32)) &&
1126 !buffer->free &&
1127 (!buffer->allow_user_free || !buffer->transaction);
1128}
1129
1130/**
1131 * binder_alloc_get_page() - get kernel pointer for given buffer offset
1132 * @alloc: binder_alloc for this proc
1133 * @buffer: binder buffer to be accessed
1134 * @buffer_offset: offset into @buffer data
1135 * @pgoffp: address to copy final page offset to
1136 *
1137 * Lookup the struct page corresponding to the address
1138 * at @buffer_offset into @buffer->user_data. If @pgoffp is not
1139 * NULL, the byte-offset into the page is written there.
1140 *
1141 * The caller is responsible to ensure that the offset points
1142 * to a valid address within the @buffer and that @buffer is
1143 * not freeable by the user. Since it can't be freed, we are
1144 * guaranteed that the corresponding elements of @alloc->pages[]
1145 * cannot change.
1146 *
1147 * Return: struct page
1148 */
1149static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1150 struct binder_buffer *buffer,
1151 binder_size_t buffer_offset,
1152 pgoff_t *pgoffp)
1153{
1154 binder_size_t buffer_space_offset = buffer_offset +
1155 (buffer->user_data - alloc->buffer);
1156 pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
1157 size_t index = buffer_space_offset >> PAGE_SHIFT;
1158 struct binder_lru_page *lru_page;
1159
1160 lru_page = &alloc->pages[index];
1161 *pgoffp = pgoff;
1162 return lru_page->page_ptr;
1163}
1164
1165/**
1166 * binder_alloc_clear_buf() - zero out buffer
1167 * @alloc: binder_alloc for this proc
1168 * @buffer: binder buffer to be cleared
1169 *
1170 * memset the given buffer to 0
1171 */
1172static void binder_alloc_clear_buf(struct binder_alloc *alloc,
1173 struct binder_buffer *buffer)
1174{
1175 size_t bytes = binder_alloc_buffer_size(alloc, buffer);
1176 binder_size_t buffer_offset = 0;
1177
1178 while (bytes) {
1179 unsigned long size;
1180 struct page *page;
1181 pgoff_t pgoff;
1182 void *kptr;
1183
1184 page = binder_alloc_get_page(alloc, buffer,
1185 buffer_offset, &pgoff);
1186 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1187 kptr = kmap(page) + pgoff;
1188 memset(kptr, 0, size);
1189 kunmap(page);
1190 bytes -= size;
1191 buffer_offset += size;
1192 }
1193}
1194
1195/**
1196 * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1197 * @alloc: binder_alloc for this proc
1198 * @buffer: binder buffer to be accessed
1199 * @buffer_offset: offset into @buffer data
1200 * @from: userspace pointer to source buffer
1201 * @bytes: bytes to copy
1202 *
1203 * Copy bytes from source userspace to target buffer.
1204 *
1205 * Return: bytes remaining to be copied
1206 */
1207unsigned long
1208binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1209 struct binder_buffer *buffer,
1210 binder_size_t buffer_offset,
1211 const void __user *from,
1212 size_t bytes)
1213{
1214 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1215 return bytes;
1216
1217 while (bytes) {
1218 unsigned long size;
1219 unsigned long ret;
1220 struct page *page;
1221 pgoff_t pgoff;
1222 void *kptr;
1223
1224 page = binder_alloc_get_page(alloc, buffer,
1225 buffer_offset, &pgoff);
1226 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1227 kptr = kmap(page) + pgoff;
1228 ret = copy_from_user(kptr, from, size);
1229 kunmap(page);
1230 if (ret)
1231 return bytes - size + ret;
1232 bytes -= size;
1233 from += size;
1234 buffer_offset += size;
1235 }
1236 return 0;
1237}
1238
1239static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1240 bool to_buffer,
1241 struct binder_buffer *buffer,
1242 binder_size_t buffer_offset,
1243 void *ptr,
1244 size_t bytes)
1245{
1246 /* All copies must be 32-bit aligned and 32-bit size */
1247 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1248 return -EINVAL;
1249
1250 while (bytes) {
1251 unsigned long size;
1252 struct page *page;
1253 pgoff_t pgoff;
1254 void *tmpptr;
1255 void *base_ptr;
1256
1257 page = binder_alloc_get_page(alloc, buffer,
1258 buffer_offset, &pgoff);
1259 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1260 base_ptr = kmap_atomic(page);
1261 tmpptr = base_ptr + pgoff;
1262 if (to_buffer)
1263 memcpy(tmpptr, ptr, size);
1264 else
1265 memcpy(ptr, tmpptr, size);
1266 /*
1267 * kunmap_atomic() takes care of flushing the cache
1268 * if this device has VIVT cache arch
1269 */
1270 kunmap_atomic(base_ptr);
1271 bytes -= size;
1272 pgoff = 0;
1273 ptr = ptr + size;
1274 buffer_offset += size;
1275 }
1276 return 0;
1277}
1278
1279int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1280 struct binder_buffer *buffer,
1281 binder_size_t buffer_offset,
1282 void *src,
1283 size_t bytes)
1284{
1285 return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1286 src, bytes);
1287}
1288
1289int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1290 void *dest,
1291 struct binder_buffer *buffer,
1292 binder_size_t buffer_offset,
1293 size_t bytes)
1294{
1295 return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
1296 dest, bytes);
1297}
1298