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 <linux/list.h>
21#include <linux/sched/mm.h>
22#include <linux/module.h>
23#include <linux/rtmutex.h>
24#include <linux/rbtree.h>
25#include <linux/seq_file.h>
26#include <linux/vmalloc.h>
27#include <linux/slab.h>
28#include <linux/sched.h>
29#include <linux/list_lru.h>
30#include <linux/ratelimit.h>
31#include <asm/cacheflush.h>
32#include <linux/uaccess.h>
33#include <linux/highmem.h>
34#include "binder_alloc.h"
35#include "binder_trace.h"
36
37struct list_lru binder_alloc_lru;
38
39static DEFINE_MUTEX(binder_alloc_mmap_lock);
40
41enum {
42 BINDER_DEBUG_USER_ERROR = 1U << 0,
43 BINDER_DEBUG_OPEN_CLOSE = 1U << 1,
44 BINDER_DEBUG_BUFFER_ALLOC = 1U << 2,
45 BINDER_DEBUG_BUFFER_ALLOC_ASYNC = 1U << 3,
46};
47static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
48
49module_param_named(debug_mask, binder_alloc_debug_mask,
50 uint, 0644);
51
52#define binder_alloc_debug(mask, x...) \
53 do { \
54 if (binder_alloc_debug_mask & mask) \
55 pr_info_ratelimited(x); \
56 } while (0)
57
58static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
59{
60 return list_entry(buffer->entry.next, struct binder_buffer, entry);
61}
62
63static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
64{
65 return list_entry(buffer->entry.prev, struct binder_buffer, entry);
66}
67
68static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
69 struct binder_buffer *buffer)
70{
71 if (list_is_last(&buffer->entry, &alloc->buffers))
72 return alloc->buffer + alloc->buffer_size - buffer->user_data;
73 return binder_buffer_next(buffer)->user_data - buffer->user_data;
74}
75
76static void binder_insert_free_buffer(struct binder_alloc *alloc,
77 struct binder_buffer *new_buffer)
78{
79 struct rb_node **p = &alloc->free_buffers.rb_node;
80 struct rb_node *parent = NULL;
81 struct binder_buffer *buffer;
82 size_t buffer_size;
83 size_t new_buffer_size;
84
85 BUG_ON(!new_buffer->free);
86
87 new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
88
89 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
90 "%d: add free buffer, size %zd, at %pK\n",
91 alloc->pid, new_buffer_size, new_buffer);
92
93 while (*p) {
94 parent = *p;
95 buffer = rb_entry(parent, struct binder_buffer, rb_node);
96 BUG_ON(!buffer->free);
97
98 buffer_size = binder_alloc_buffer_size(alloc, buffer);
99
100 if (new_buffer_size < buffer_size)
101 p = &parent->rb_left;
102 else
103 p = &parent->rb_right;
104 }
105 rb_link_node(&new_buffer->rb_node, parent, p);
106 rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
107}
108
109static void binder_insert_allocated_buffer_locked(
110 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
111{
112 struct rb_node **p = &alloc->allocated_buffers.rb_node;
113 struct rb_node *parent = NULL;
114 struct binder_buffer *buffer;
115
116 BUG_ON(new_buffer->free);
117
118 while (*p) {
119 parent = *p;
120 buffer = rb_entry(parent, struct binder_buffer, rb_node);
121 BUG_ON(buffer->free);
122
123 if (new_buffer->user_data < buffer->user_data)
124 p = &parent->rb_left;
125 else if (new_buffer->user_data > buffer->user_data)
126 p = &parent->rb_right;
127 else
128 BUG();
129 }
130 rb_link_node(&new_buffer->rb_node, parent, p);
131 rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
132}
133
134static struct binder_buffer *binder_alloc_prepare_to_free_locked(
135 struct binder_alloc *alloc,
136 uintptr_t user_ptr)
137{
138 struct rb_node *n = alloc->allocated_buffers.rb_node;
139 struct binder_buffer *buffer;
140 void __user *uptr;
141
142 uptr = (void __user *)user_ptr;
143
144 while (n) {
145 buffer = rb_entry(n, struct binder_buffer, rb_node);
146 BUG_ON(buffer->free);
147
148 if (uptr < buffer->user_data)
149 n = n->rb_left;
150 else if (uptr > buffer->user_data)
151 n = n->rb_right;
152 else {
153 /*
154 * Guard against user threads attempting to
155 * free the buffer when in use by kernel or
156 * after it's already been freed.
157 */
158 if (!buffer->allow_user_free)
159 return ERR_PTR(-EPERM);
160 buffer->allow_user_free = 0;
161 return buffer;
162 }
163 }
164 return NULL;
165}
166
167/**
168 * binder_alloc_buffer_lookup() - get buffer given user ptr
169 * @alloc: binder_alloc for this proc
170 * @user_ptr: User pointer to buffer data
171 *
172 * Validate userspace pointer to buffer data and return buffer corresponding to
173 * that user pointer. Search the rb tree for buffer that matches user data
174 * pointer.
175 *
176 * Return: Pointer to buffer or NULL
177 */
178struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
179 uintptr_t user_ptr)
180{
181 struct binder_buffer *buffer;
182
183 mutex_lock(&alloc->mutex);
184 buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
185 mutex_unlock(&alloc->mutex);
186 return buffer;
187}
188
189static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
190 void __user *start, void __user *end)
191{
192 void __user *page_addr;
193 unsigned long user_page_addr;
194 struct binder_lru_page *page;
195 struct vm_area_struct *vma = NULL;
196 struct mm_struct *mm = NULL;
197 bool need_mm = false;
198
199 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
200 "%d: %s pages %pK-%pK\n", alloc->pid,
201 allocate ? "allocate" : "free", start, end);
202
203 if (end <= start)
204 return 0;
205
206 trace_binder_update_page_range(alloc, allocate, start, end);
207
208 if (allocate == 0)
209 goto free_range;
210
211 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
212 page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
213 if (!page->page_ptr) {
214 need_mm = true;
215 break;
216 }
217 }
218
219 if (need_mm && mmget_not_zero(alloc->vma_vm_mm))
220 mm = alloc->vma_vm_mm;
221
222 if (mm) {
223 down_read(&mm->mmap_sem);
224 vma = alloc->vma;
225 }
226
227 if (!vma && need_mm) {
228 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
229 "%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
230 alloc->pid);
231 goto err_no_vma;
232 }
233
234 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
235 int ret;
236 bool on_lru;
237 size_t index;
238
239 index = (page_addr - alloc->buffer) / PAGE_SIZE;
240 page = &alloc->pages[index];
241
242 if (page->page_ptr) {
243 trace_binder_alloc_lru_start(alloc, index);
244
245 on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
246 WARN_ON(!on_lru);
247
248 trace_binder_alloc_lru_end(alloc, index);
249 continue;
250 }
251
252 if (WARN_ON(!vma))
253 goto err_page_ptr_cleared;
254
255 trace_binder_alloc_page_start(alloc, index);
256 page->page_ptr = alloc_page(GFP_KERNEL |
257 __GFP_HIGHMEM |
258 __GFP_ZERO);
259 if (!page->page_ptr) {
260 pr_err("%d: binder_alloc_buf failed for page at %pK\n",
261 alloc->pid, page_addr);
262 goto err_alloc_page_failed;
263 }
264 page->alloc = alloc;
265 INIT_LIST_HEAD(&page->lru);
266
267 user_page_addr = (uintptr_t)page_addr;
268 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
269 if (ret) {
270 pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
271 alloc->pid, user_page_addr);
272 goto err_vm_insert_page_failed;
273 }
274
275 if (index + 1 > alloc->pages_high)
276 alloc->pages_high = index + 1;
277
278 trace_binder_alloc_page_end(alloc, index);
279 /* vm_insert_page does not seem to increment the refcount */
280 }
281 if (mm) {
282 up_read(&mm->mmap_sem);
283 mmput(mm);
284 }
285 return 0;
286
287free_range:
288 for (page_addr = end - PAGE_SIZE; page_addr >= start;
289 page_addr -= PAGE_SIZE) {
290 bool ret;
291 size_t index;
292
293 index = (page_addr - alloc->buffer) / PAGE_SIZE;
294 page = &alloc->pages[index];
295
296 trace_binder_free_lru_start(alloc, index);
297
298 ret = list_lru_add(&binder_alloc_lru, &page->lru);
299 WARN_ON(!ret);
300
301 trace_binder_free_lru_end(alloc, index);
302 continue;
303
304err_vm_insert_page_failed:
305 __free_page(page->page_ptr);
306 page->page_ptr = NULL;
307err_alloc_page_failed:
308err_page_ptr_cleared:
309 ;
310 }
311err_no_vma:
312 if (mm) {
313 up_read(&mm->mmap_sem);
314 mmput(mm);
315 }
316 return vma ? -ENOMEM : -ESRCH;
317}
318
319
320static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
321 struct vm_area_struct *vma)
322{
323 if (vma)
324 alloc->vma_vm_mm = vma->vm_mm;
325 /*
326 * If we see alloc->vma is not NULL, buffer data structures set up
327 * completely. Look at smp_rmb side binder_alloc_get_vma.
328 * We also want to guarantee new alloc->vma_vm_mm is always visible
329 * if alloc->vma is set.
330 */
331 smp_wmb();
332 alloc->vma = vma;
333}
334
335static inline struct vm_area_struct *binder_alloc_get_vma(
336 struct binder_alloc *alloc)
337{
338 struct vm_area_struct *vma = NULL;
339
340 if (alloc->vma) {
341 /* Look at description in binder_alloc_set_vma */
342 smp_rmb();
343 vma = alloc->vma;
344 }
345 return vma;
346}
347
348static struct binder_buffer *binder_alloc_new_buf_locked(
349 struct binder_alloc *alloc,
350 size_t data_size,
351 size_t offsets_size,
352 size_t extra_buffers_size,
353 int is_async)
354{
355 struct rb_node *n = alloc->free_buffers.rb_node;
356 struct binder_buffer *buffer;
357 size_t buffer_size;
358 struct rb_node *best_fit = NULL;
359 void __user *has_page_addr;
360 void __user *end_page_addr;
361 size_t size, data_offsets_size;
362 int ret;
363
364 if (!binder_alloc_get_vma(alloc)) {
365 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
366 "%d: binder_alloc_buf, no vma\n",
367 alloc->pid);
368 return ERR_PTR(-ESRCH);
369 }
370
371 data_offsets_size = ALIGN(data_size, sizeof(void *)) +
372 ALIGN(offsets_size, sizeof(void *));
373
374 if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
375 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
376 "%d: got transaction with invalid size %zd-%zd\n",
377 alloc->pid, data_size, offsets_size);
378 return ERR_PTR(-EINVAL);
379 }
380 size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
381 if (size < data_offsets_size || size < extra_buffers_size) {
382 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
383 "%d: got transaction with invalid extra_buffers_size %zd\n",
384 alloc->pid, extra_buffers_size);
385 return ERR_PTR(-EINVAL);
386 }
387 if (is_async &&
388 alloc->free_async_space < size + sizeof(struct binder_buffer)) {
389 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
390 "%d: binder_alloc_buf size %zd failed, no async space left\n",
391 alloc->pid, size);
392 return ERR_PTR(-ENOSPC);
393 }
394
395 /* Pad 0-size buffers so they get assigned unique addresses */
396 size = max(size, sizeof(void *));
397
398 while (n) {
399 buffer = rb_entry(n, struct binder_buffer, rb_node);
400 BUG_ON(!buffer->free);
401 buffer_size = binder_alloc_buffer_size(alloc, buffer);
402
403 if (size < buffer_size) {
404 best_fit = n;
405 n = n->rb_left;
406 } else if (size > buffer_size)
407 n = n->rb_right;
408 else {
409 best_fit = n;
410 break;
411 }
412 }
413 if (best_fit == NULL) {
414 size_t allocated_buffers = 0;
415 size_t largest_alloc_size = 0;
416 size_t total_alloc_size = 0;
417 size_t free_buffers = 0;
418 size_t largest_free_size = 0;
419 size_t total_free_size = 0;
420
421 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
422 n = rb_next(n)) {
423 buffer = rb_entry(n, struct binder_buffer, rb_node);
424 buffer_size = binder_alloc_buffer_size(alloc, buffer);
425 allocated_buffers++;
426 total_alloc_size += buffer_size;
427 if (buffer_size > largest_alloc_size)
428 largest_alloc_size = buffer_size;
429 }
430 for (n = rb_first(&alloc->free_buffers); n != NULL;
431 n = rb_next(n)) {
432 buffer = rb_entry(n, struct binder_buffer, rb_node);
433 buffer_size = binder_alloc_buffer_size(alloc, buffer);
434 free_buffers++;
435 total_free_size += buffer_size;
436 if (buffer_size > largest_free_size)
437 largest_free_size = buffer_size;
438 }
439 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
440 "%d: binder_alloc_buf size %zd failed, no address space\n",
441 alloc->pid, size);
442 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
443 "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
444 total_alloc_size, allocated_buffers,
445 largest_alloc_size, total_free_size,
446 free_buffers, largest_free_size);
447 return ERR_PTR(-ENOSPC);
448 }
449 if (n == NULL) {
450 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
451 buffer_size = binder_alloc_buffer_size(alloc, buffer);
452 }
453
454 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
455 "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
456 alloc->pid, size, buffer, buffer_size);
457
458 has_page_addr = (void __user *)
459 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
460 WARN_ON(n && buffer_size != size);
461 end_page_addr =
462 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
463 if (end_page_addr > has_page_addr)
464 end_page_addr = has_page_addr;
465 ret = binder_update_page_range(alloc, 1, (void __user *)
466 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
467 if (ret)
468 return ERR_PTR(ret);
469
470 if (buffer_size != size) {
471 struct binder_buffer *new_buffer;
472
473 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
474 if (!new_buffer) {
475 pr_err("%s: %d failed to alloc new buffer struct\n",
476 __func__, alloc->pid);
477 goto err_alloc_buf_struct_failed;
478 }
479 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
480 list_add(&new_buffer->entry, &buffer->entry);
481 new_buffer->free = 1;
482 binder_insert_free_buffer(alloc, new_buffer);
483 }
484
485 rb_erase(best_fit, &alloc->free_buffers);
486 buffer->free = 0;
487 buffer->allow_user_free = 0;
488 binder_insert_allocated_buffer_locked(alloc, buffer);
489 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
490 "%d: binder_alloc_buf size %zd got %pK\n",
491 alloc->pid, size, buffer);
492 buffer->data_size = data_size;
493 buffer->offsets_size = offsets_size;
494 buffer->async_transaction = is_async;
495 buffer->extra_buffers_size = extra_buffers_size;
496 if (is_async) {
497 alloc->free_async_space -= size + sizeof(struct binder_buffer);
498 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
499 "%d: binder_alloc_buf size %zd async free %zd\n",
500 alloc->pid, size, alloc->free_async_space);
501 }
502 return buffer;
503
504err_alloc_buf_struct_failed:
505 binder_update_page_range(alloc, 0, (void __user *)
506 PAGE_ALIGN((uintptr_t)buffer->user_data),
507 end_page_addr);
508 return ERR_PTR(-ENOMEM);
509}
510
511/**
512 * binder_alloc_new_buf() - Allocate a new binder buffer
513 * @alloc: binder_alloc for this proc
514 * @data_size: size of user data buffer
515 * @offsets_size: user specified buffer offset
516 * @extra_buffers_size: size of extra space for meta-data (eg, security context)
517 * @is_async: buffer for async transaction
518 *
519 * Allocate a new buffer given the requested sizes. Returns
520 * the kernel version of the buffer pointer. The size allocated
521 * is the sum of the three given sizes (each rounded up to
522 * pointer-sized boundary)
523 *
524 * Return: The allocated buffer or %NULL if error
525 */
526struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
527 size_t data_size,
528 size_t offsets_size,
529 size_t extra_buffers_size,
530 int is_async)
531{
532 struct binder_buffer *buffer;
533
534 mutex_lock(&alloc->mutex);
535 buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
536 extra_buffers_size, is_async);
537 mutex_unlock(&alloc->mutex);
538 return buffer;
539}
540
541static void __user *buffer_start_page(struct binder_buffer *buffer)
542{
543 return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
544}
545
546static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
547{
548 return (void __user *)
549 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
550}
551
552static void binder_delete_free_buffer(struct binder_alloc *alloc,
553 struct binder_buffer *buffer)
554{
555 struct binder_buffer *prev, *next = NULL;
556 bool to_free = true;
557 BUG_ON(alloc->buffers.next == &buffer->entry);
558 prev = binder_buffer_prev(buffer);
559 BUG_ON(!prev->free);
560 if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
561 to_free = false;
562 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
563 "%d: merge free, buffer %pK share page with %pK\n",
564 alloc->pid, buffer->user_data,
565 prev->user_data);
566 }
567
568 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
569 next = binder_buffer_next(buffer);
570 if (buffer_start_page(next) == buffer_start_page(buffer)) {
571 to_free = false;
572 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
573 "%d: merge free, buffer %pK share page with %pK\n",
574 alloc->pid,
575 buffer->user_data,
576 next->user_data);
577 }
578 }
579
580 if (PAGE_ALIGNED(buffer->user_data)) {
581 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
582 "%d: merge free, buffer start %pK is page aligned\n",
583 alloc->pid, buffer->user_data);
584 to_free = false;
585 }
586
587 if (to_free) {
588 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
589 "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
590 alloc->pid, buffer->user_data,
591 prev->user_data,
592 next ? next->user_data : NULL);
593 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
594 buffer_start_page(buffer) + PAGE_SIZE);
595 }
596 list_del(&buffer->entry);
597 kfree(buffer);
598}
599
600static void binder_free_buf_locked(struct binder_alloc *alloc,
601 struct binder_buffer *buffer)
602{
603 size_t size, buffer_size;
604
605 buffer_size = binder_alloc_buffer_size(alloc, buffer);
606
607 size = ALIGN(buffer->data_size, sizeof(void *)) +
608 ALIGN(buffer->offsets_size, sizeof(void *)) +
609 ALIGN(buffer->extra_buffers_size, sizeof(void *));
610
611 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
612 "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
613 alloc->pid, buffer, size, buffer_size);
614
615 BUG_ON(buffer->free);
616 BUG_ON(size > buffer_size);
617 BUG_ON(buffer->transaction != NULL);
618 BUG_ON(buffer->user_data < alloc->buffer);
619 BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
620
621 if (buffer->async_transaction) {
622 alloc->free_async_space += size + sizeof(struct binder_buffer);
623
624 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
625 "%d: binder_free_buf size %zd async free %zd\n",
626 alloc->pid, size, alloc->free_async_space);
627 }
628
629 binder_update_page_range(alloc, 0,
630 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
631 (void __user *)(((uintptr_t)
632 buffer->user_data + buffer_size) & PAGE_MASK));
633
634 rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
635 buffer->free = 1;
636 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
637 struct binder_buffer *next = binder_buffer_next(buffer);
638
639 if (next->free) {
640 rb_erase(&next->rb_node, &alloc->free_buffers);
641 binder_delete_free_buffer(alloc, next);
642 }
643 }
644 if (alloc->buffers.next != &buffer->entry) {
645 struct binder_buffer *prev = binder_buffer_prev(buffer);
646
647 if (prev->free) {
648 binder_delete_free_buffer(alloc, buffer);
649 rb_erase(&prev->rb_node, &alloc->free_buffers);
650 buffer = prev;
651 }
652 }
653 binder_insert_free_buffer(alloc, buffer);
654}
655
656/**
657 * binder_alloc_free_buf() - free a binder buffer
658 * @alloc: binder_alloc for this proc
659 * @buffer: kernel pointer to buffer
660 *
661 * Free the buffer allocated via binder_alloc_new_buffer()
662 */
663void binder_alloc_free_buf(struct binder_alloc *alloc,
664 struct binder_buffer *buffer)
665{
666 mutex_lock(&alloc->mutex);
667 binder_free_buf_locked(alloc, buffer);
668 mutex_unlock(&alloc->mutex);
669}
670
671/**
672 * binder_alloc_mmap_handler() - map virtual address space for proc
673 * @alloc: alloc structure for this proc
674 * @vma: vma passed to mmap()
675 *
676 * Called by binder_mmap() to initialize the space specified in
677 * vma for allocating binder buffers
678 *
679 * Return:
680 * 0 = success
681 * -EBUSY = address space already mapped
682 * -ENOMEM = failed to map memory to given address space
683 */
684int binder_alloc_mmap_handler(struct binder_alloc *alloc,
685 struct vm_area_struct *vma)
686{
687 int ret;
688 const char *failure_string;
689 struct binder_buffer *buffer;
690
691 mutex_lock(&binder_alloc_mmap_lock);
692 if (alloc->buffer) {
693 ret = -EBUSY;
694 failure_string = "already mapped";
695 goto err_already_mapped;
696 }
697
698 alloc->buffer = (void __user *)vma->vm_start;
699 mutex_unlock(&binder_alloc_mmap_lock);
700
701 alloc->pages = kcalloc((vma->vm_end - vma->vm_start) / PAGE_SIZE,
702 sizeof(alloc->pages[0]),
703 GFP_KERNEL);
704 if (alloc->pages == NULL) {
705 ret = -ENOMEM;
706 failure_string = "alloc page array";
707 goto err_alloc_pages_failed;
708 }
709 alloc->buffer_size = vma->vm_end - vma->vm_start;
710
711 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
712 if (!buffer) {
713 ret = -ENOMEM;
714 failure_string = "alloc buffer struct";
715 goto err_alloc_buf_struct_failed;
716 }
717
718 buffer->user_data = alloc->buffer;
719 list_add(&buffer->entry, &alloc->buffers);
720 buffer->free = 1;
721 binder_insert_free_buffer(alloc, buffer);
722 alloc->free_async_space = alloc->buffer_size / 2;
723 binder_alloc_set_vma(alloc, vma);
724 mmgrab(alloc->vma_vm_mm);
725
726 return 0;
727
728err_alloc_buf_struct_failed:
729 kfree(alloc->pages);
730 alloc->pages = NULL;
731err_alloc_pages_failed:
732 mutex_lock(&binder_alloc_mmap_lock);
733 alloc->buffer = NULL;
734err_already_mapped:
735 mutex_unlock(&binder_alloc_mmap_lock);
736 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
737 "%s: %d %lx-%lx %s failed %d\n", __func__,
738 alloc->pid, vma->vm_start, vma->vm_end,
739 failure_string, ret);
740 return ret;
741}
742
743
744void binder_alloc_deferred_release(struct binder_alloc *alloc)
745{
746 struct rb_node *n;
747 int buffers, page_count;
748 struct binder_buffer *buffer;
749
750 buffers = 0;
751 mutex_lock(&alloc->mutex);
752 BUG_ON(alloc->vma);
753
754 while ((n = rb_first(&alloc->allocated_buffers))) {
755 buffer = rb_entry(n, struct binder_buffer, rb_node);
756
757 /* Transaction should already have been freed */
758 BUG_ON(buffer->transaction);
759
760 binder_free_buf_locked(alloc, buffer);
761 buffers++;
762 }
763
764 while (!list_empty(&alloc->buffers)) {
765 buffer = list_first_entry(&alloc->buffers,
766 struct binder_buffer, entry);
767 WARN_ON(!buffer->free);
768
769 list_del(&buffer->entry);
770 WARN_ON_ONCE(!list_empty(&alloc->buffers));
771 kfree(buffer);
772 }
773
774 page_count = 0;
775 if (alloc->pages) {
776 int i;
777
778 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
779 void __user *page_addr;
780 bool on_lru;
781
782 if (!alloc->pages[i].page_ptr)
783 continue;
784
785 on_lru = list_lru_del(&binder_alloc_lru,
786 &alloc->pages[i].lru);
787 page_addr = alloc->buffer + i * PAGE_SIZE;
788 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
789 "%s: %d: page %d at %pK %s\n",
790 __func__, alloc->pid, i, page_addr,
791 on_lru ? "on lru" : "active");
792 __free_page(alloc->pages[i].page_ptr);
793 page_count++;
794 }
795 kfree(alloc->pages);
796 }
797 mutex_unlock(&alloc->mutex);
798 if (alloc->vma_vm_mm)
799 mmdrop(alloc->vma_vm_mm);
800
801 binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
802 "%s: %d buffers %d, pages %d\n",
803 __func__, alloc->pid, buffers, page_count);
804}
805
806static void print_binder_buffer(struct seq_file *m, const char *prefix,
807 struct binder_buffer *buffer)
808{
809 seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
810 prefix, buffer->debug_id, buffer->user_data,
811 buffer->data_size, buffer->offsets_size,
812 buffer->extra_buffers_size,
813 buffer->transaction ? "active" : "delivered");
814}
815
816/**
817 * binder_alloc_print_allocated() - print buffer info
818 * @m: seq_file for output via seq_printf()
819 * @alloc: binder_alloc for this proc
820 *
821 * Prints information about every buffer associated with
822 * the binder_alloc state to the given seq_file
823 */
824void binder_alloc_print_allocated(struct seq_file *m,
825 struct binder_alloc *alloc)
826{
827 struct rb_node *n;
828
829 mutex_lock(&alloc->mutex);
830 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
831 print_binder_buffer(m, " buffer",
832 rb_entry(n, struct binder_buffer, rb_node));
833 mutex_unlock(&alloc->mutex);
834}
835
836/**
837 * binder_alloc_print_pages() - print page usage
838 * @m: seq_file for output via seq_printf()
839 * @alloc: binder_alloc for this proc
840 */
841void binder_alloc_print_pages(struct seq_file *m,
842 struct binder_alloc *alloc)
843{
844 struct binder_lru_page *page;
845 int i;
846 int active = 0;
847 int lru = 0;
848 int free = 0;
849
850 mutex_lock(&alloc->mutex);
851 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
852 page = &alloc->pages[i];
853 if (!page->page_ptr)
854 free++;
855 else if (list_empty(&page->lru))
856 active++;
857 else
858 lru++;
859 }
860 mutex_unlock(&alloc->mutex);
861 seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
862 seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);
863}
864
865/**
866 * binder_alloc_get_allocated_count() - return count of buffers
867 * @alloc: binder_alloc for this proc
868 *
869 * Return: count of allocated buffers
870 */
871int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
872{
873 struct rb_node *n;
874 int count = 0;
875
876 mutex_lock(&alloc->mutex);
877 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
878 count++;
879 mutex_unlock(&alloc->mutex);
880 return count;
881}
882
883
884/**
885 * binder_alloc_vma_close() - invalidate address space
886 * @alloc: binder_alloc for this proc
887 *
888 * Called from binder_vma_close() when releasing address space.
889 * Clears alloc->vma to prevent new incoming transactions from
890 * allocating more buffers.
891 */
892void binder_alloc_vma_close(struct binder_alloc *alloc)
893{
894 binder_alloc_set_vma(alloc, NULL);
895}
896
897/**
898 * binder_alloc_free_page() - shrinker callback to free pages
899 * @item: item to free
900 * @lock: lock protecting the item
901 * @cb_arg: callback argument
902 *
903 * Called from list_lru_walk() in binder_shrink_scan() to free
904 * up pages when the system is under memory pressure.
905 */
906enum lru_status binder_alloc_free_page(struct list_head *item,
907 struct list_lru_one *lru,
908 spinlock_t *lock,
909 void *cb_arg)
910 __must_hold(lock)
911{
912 struct mm_struct *mm = NULL;
913 struct binder_lru_page *page = container_of(item,
914 struct binder_lru_page,
915 lru);
916 struct binder_alloc *alloc;
917 uintptr_t page_addr;
918 size_t index;
919 struct vm_area_struct *vma;
920
921 alloc = page->alloc;
922 if (!mutex_trylock(&alloc->mutex))
923 goto err_get_alloc_mutex_failed;
924
925 if (!page->page_ptr)
926 goto err_page_already_freed;
927
928 index = page - alloc->pages;
929 page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
930 vma = binder_alloc_get_vma(alloc);
931 if (vma) {
932 if (!mmget_not_zero(alloc->vma_vm_mm))
933 goto err_mmget;
934 mm = alloc->vma_vm_mm;
935 if (!down_read_trylock(&mm->mmap_sem))
936 goto err_down_write_mmap_sem_failed;
937 }
938
939 list_lru_isolate(lru, item);
940 spin_unlock(lock);
941
942 if (vma) {
943 trace_binder_unmap_user_start(alloc, index);
944
945 zap_page_range(vma, page_addr, PAGE_SIZE);
946
947 trace_binder_unmap_user_end(alloc, index);
948
949 up_read(&mm->mmap_sem);
950 mmput(mm);
951 }
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_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}
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 void 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 BUG_ON(!check_buffer(alloc, buffer, buffer_offset, bytes));
1142
1143 while (bytes) {
1144 unsigned long size;
1145 struct page *page;
1146 pgoff_t pgoff;
1147 void *tmpptr;
1148 void *base_ptr;
1149
1150 page = binder_alloc_get_page(alloc, buffer,
1151 buffer_offset, &pgoff);
1152 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1153 base_ptr = kmap_atomic(page);
1154 tmpptr = base_ptr + pgoff;
1155 if (to_buffer)
1156 memcpy(tmpptr, ptr, size);
1157 else
1158 memcpy(ptr, tmpptr, size);
1159 /*
1160 * kunmap_atomic() takes care of flushing the cache
1161 * if this device has VIVT cache arch
1162 */
1163 kunmap_atomic(base_ptr);
1164 bytes -= size;
1165 pgoff = 0;
1166 ptr = ptr + size;
1167 buffer_offset += size;
1168 }
1169}
1170
1171void binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1172 struct binder_buffer *buffer,
1173 binder_size_t buffer_offset,
1174 void *src,
1175 size_t bytes)
1176{
1177 binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1178 src, bytes);
1179}
1180
1181void binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1182 void *dest,
1183 struct binder_buffer *buffer,
1184 binder_size_t buffer_offset,
1185 size_t bytes)
1186{
1187 binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
1188 dest, bytes);
1189}
1190
1191