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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->mm))
212 mm = alloc->mm;
213
214 if (mm) {
215 mmap_read_lock(mm);
216 vma = vma_lookup(mm, alloc->vma_addr);
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
312static inline struct vm_area_struct *binder_alloc_get_vma(
313 struct binder_alloc *alloc)
314{
315 struct vm_area_struct *vma = NULL;
316
317 if (alloc->vma_addr)
318 vma = vma_lookup(alloc->mm, alloc->vma_addr);
319
320 return vma;
321}
322
323static bool debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
324{
325 /*
326 * Find the amount and size of buffers allocated by the current caller;
327 * The idea is that once we cross the threshold, whoever is responsible
328 * for the low async space is likely to try to send another async txn,
329 * and at some point we'll catch them in the act. This is more efficient
330 * than keeping a map per pid.
331 */
332 struct rb_node *n;
333 struct binder_buffer *buffer;
334 size_t total_alloc_size = 0;
335 size_t num_buffers = 0;
336
337 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
338 n = rb_next(n)) {
339 buffer = rb_entry(n, struct binder_buffer, rb_node);
340 if (buffer->pid != pid)
341 continue;
342 if (!buffer->async_transaction)
343 continue;
344 total_alloc_size += binder_alloc_buffer_size(alloc, buffer)
345 + sizeof(struct binder_buffer);
346 num_buffers++;
347 }
348
349 /*
350 * Warn if this pid has more than 50 transactions, or more than 50% of
351 * async space (which is 25% of total buffer size). Oneway spam is only
352 * detected when the threshold is exceeded.
353 */
354 if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) {
355 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
356 "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n",
357 alloc->pid, pid, num_buffers, total_alloc_size);
358 if (!alloc->oneway_spam_detected) {
359 alloc->oneway_spam_detected = true;
360 return true;
361 }
362 }
363 return false;
364}
365
366static struct binder_buffer *binder_alloc_new_buf_locked(
367 struct binder_alloc *alloc,
368 size_t data_size,
369 size_t offsets_size,
370 size_t extra_buffers_size,
371 int is_async,
372 int pid)
373{
374 struct rb_node *n = alloc->free_buffers.rb_node;
375 struct binder_buffer *buffer;
376 size_t buffer_size;
377 struct rb_node *best_fit = NULL;
378 void __user *has_page_addr;
379 void __user *end_page_addr;
380 size_t size, data_offsets_size;
381 int ret;
382
383 mmap_read_lock(alloc->mm);
384 if (!binder_alloc_get_vma(alloc)) {
385 mmap_read_unlock(alloc->mm);
386 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
387 "%d: binder_alloc_buf, no vma\n",
388 alloc->pid);
389 return ERR_PTR(-ESRCH);
390 }
391 mmap_read_unlock(alloc->mm);
392
393 data_offsets_size = ALIGN(data_size, sizeof(void *)) +
394 ALIGN(offsets_size, sizeof(void *));
395
396 if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
397 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
398 "%d: got transaction with invalid size %zd-%zd\n",
399 alloc->pid, data_size, offsets_size);
400 return ERR_PTR(-EINVAL);
401 }
402 size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
403 if (size < data_offsets_size || size < extra_buffers_size) {
404 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
405 "%d: got transaction with invalid extra_buffers_size %zd\n",
406 alloc->pid, extra_buffers_size);
407 return ERR_PTR(-EINVAL);
408 }
409 if (is_async &&
410 alloc->free_async_space < size + sizeof(struct binder_buffer)) {
411 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
412 "%d: binder_alloc_buf size %zd failed, no async space left\n",
413 alloc->pid, size);
414 return ERR_PTR(-ENOSPC);
415 }
416
417 /* Pad 0-size buffers so they get assigned unique addresses */
418 size = max(size, sizeof(void *));
419
420 while (n) {
421 buffer = rb_entry(n, struct binder_buffer, rb_node);
422 BUG_ON(!buffer->free);
423 buffer_size = binder_alloc_buffer_size(alloc, buffer);
424
425 if (size < buffer_size) {
426 best_fit = n;
427 n = n->rb_left;
428 } else if (size > buffer_size)
429 n = n->rb_right;
430 else {
431 best_fit = n;
432 break;
433 }
434 }
435 if (best_fit == NULL) {
436 size_t allocated_buffers = 0;
437 size_t largest_alloc_size = 0;
438 size_t total_alloc_size = 0;
439 size_t free_buffers = 0;
440 size_t largest_free_size = 0;
441 size_t total_free_size = 0;
442
443 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
444 n = rb_next(n)) {
445 buffer = rb_entry(n, struct binder_buffer, rb_node);
446 buffer_size = binder_alloc_buffer_size(alloc, buffer);
447 allocated_buffers++;
448 total_alloc_size += buffer_size;
449 if (buffer_size > largest_alloc_size)
450 largest_alloc_size = buffer_size;
451 }
452 for (n = rb_first(&alloc->free_buffers); n != NULL;
453 n = rb_next(n)) {
454 buffer = rb_entry(n, struct binder_buffer, rb_node);
455 buffer_size = binder_alloc_buffer_size(alloc, buffer);
456 free_buffers++;
457 total_free_size += buffer_size;
458 if (buffer_size > largest_free_size)
459 largest_free_size = buffer_size;
460 }
461 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
462 "%d: binder_alloc_buf size %zd failed, no address space\n",
463 alloc->pid, size);
464 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
465 "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
466 total_alloc_size, allocated_buffers,
467 largest_alloc_size, total_free_size,
468 free_buffers, largest_free_size);
469 return ERR_PTR(-ENOSPC);
470 }
471 if (n == NULL) {
472 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
473 buffer_size = binder_alloc_buffer_size(alloc, buffer);
474 }
475
476 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
477 "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
478 alloc->pid, size, buffer, buffer_size);
479
480 has_page_addr = (void __user *)
481 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
482 WARN_ON(n && buffer_size != size);
483 end_page_addr =
484 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
485 if (end_page_addr > has_page_addr)
486 end_page_addr = has_page_addr;
487 ret = binder_update_page_range(alloc, 1, (void __user *)
488 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
489 if (ret)
490 return ERR_PTR(ret);
491
492 if (buffer_size != size) {
493 struct binder_buffer *new_buffer;
494
495 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
496 if (!new_buffer) {
497 pr_err("%s: %d failed to alloc new buffer struct\n",
498 __func__, alloc->pid);
499 goto err_alloc_buf_struct_failed;
500 }
501 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
502 list_add(&new_buffer->entry, &buffer->entry);
503 new_buffer->free = 1;
504 binder_insert_free_buffer(alloc, new_buffer);
505 }
506
507 rb_erase(best_fit, &alloc->free_buffers);
508 buffer->free = 0;
509 buffer->allow_user_free = 0;
510 binder_insert_allocated_buffer_locked(alloc, buffer);
511 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
512 "%d: binder_alloc_buf size %zd got %pK\n",
513 alloc->pid, size, buffer);
514 buffer->data_size = data_size;
515 buffer->offsets_size = offsets_size;
516 buffer->async_transaction = is_async;
517 buffer->extra_buffers_size = extra_buffers_size;
518 buffer->pid = pid;
519 buffer->oneway_spam_suspect = false;
520 if (is_async) {
521 alloc->free_async_space -= size + sizeof(struct binder_buffer);
522 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
523 "%d: binder_alloc_buf size %zd async free %zd\n",
524 alloc->pid, size, alloc->free_async_space);
525 if (alloc->free_async_space < alloc->buffer_size / 10) {
526 /*
527 * Start detecting spammers once we have less than 20%
528 * of async space left (which is less than 10% of total
529 * buffer size).
530 */
531 buffer->oneway_spam_suspect = debug_low_async_space_locked(alloc, pid);
532 } else {
533 alloc->oneway_spam_detected = false;
534 }
535 }
536 return buffer;
537
538err_alloc_buf_struct_failed:
539 binder_update_page_range(alloc, 0, (void __user *)
540 PAGE_ALIGN((uintptr_t)buffer->user_data),
541 end_page_addr);
542 return ERR_PTR(-ENOMEM);
543}
544
545/**
546 * binder_alloc_new_buf() - Allocate a new binder buffer
547 * @alloc: binder_alloc for this proc
548 * @data_size: size of user data buffer
549 * @offsets_size: user specified buffer offset
550 * @extra_buffers_size: size of extra space for meta-data (eg, security context)
551 * @is_async: buffer for async transaction
552 * @pid: pid to attribute allocation to (used for debugging)
553 *
554 * Allocate a new buffer given the requested sizes. Returns
555 * the kernel version of the buffer pointer. The size allocated
556 * is the sum of the three given sizes (each rounded up to
557 * pointer-sized boundary)
558 *
559 * Return: The allocated buffer or %NULL if error
560 */
561struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
562 size_t data_size,
563 size_t offsets_size,
564 size_t extra_buffers_size,
565 int is_async,
566 int pid)
567{
568 struct binder_buffer *buffer;
569
570 mutex_lock(&alloc->mutex);
571 buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
572 extra_buffers_size, is_async, pid);
573 mutex_unlock(&alloc->mutex);
574 return buffer;
575}
576
577static void __user *buffer_start_page(struct binder_buffer *buffer)
578{
579 return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
580}
581
582static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
583{
584 return (void __user *)
585 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
586}
587
588static void binder_delete_free_buffer(struct binder_alloc *alloc,
589 struct binder_buffer *buffer)
590{
591 struct binder_buffer *prev, *next = NULL;
592 bool to_free = true;
593
594 BUG_ON(alloc->buffers.next == &buffer->entry);
595 prev = binder_buffer_prev(buffer);
596 BUG_ON(!prev->free);
597 if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
598 to_free = false;
599 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
600 "%d: merge free, buffer %pK share page with %pK\n",
601 alloc->pid, buffer->user_data,
602 prev->user_data);
603 }
604
605 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
606 next = binder_buffer_next(buffer);
607 if (buffer_start_page(next) == buffer_start_page(buffer)) {
608 to_free = false;
609 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
610 "%d: merge free, buffer %pK share page with %pK\n",
611 alloc->pid,
612 buffer->user_data,
613 next->user_data);
614 }
615 }
616
617 if (PAGE_ALIGNED(buffer->user_data)) {
618 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
619 "%d: merge free, buffer start %pK is page aligned\n",
620 alloc->pid, buffer->user_data);
621 to_free = false;
622 }
623
624 if (to_free) {
625 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
626 "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
627 alloc->pid, buffer->user_data,
628 prev->user_data,
629 next ? next->user_data : NULL);
630 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
631 buffer_start_page(buffer) + PAGE_SIZE);
632 }
633 list_del(&buffer->entry);
634 kfree(buffer);
635}
636
637static void binder_free_buf_locked(struct binder_alloc *alloc,
638 struct binder_buffer *buffer)
639{
640 size_t size, buffer_size;
641
642 buffer_size = binder_alloc_buffer_size(alloc, buffer);
643
644 size = ALIGN(buffer->data_size, sizeof(void *)) +
645 ALIGN(buffer->offsets_size, sizeof(void *)) +
646 ALIGN(buffer->extra_buffers_size, sizeof(void *));
647
648 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
649 "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
650 alloc->pid, buffer, size, buffer_size);
651
652 BUG_ON(buffer->free);
653 BUG_ON(size > buffer_size);
654 BUG_ON(buffer->transaction != NULL);
655 BUG_ON(buffer->user_data < alloc->buffer);
656 BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
657
658 if (buffer->async_transaction) {
659 alloc->free_async_space += buffer_size + sizeof(struct binder_buffer);
660
661 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
662 "%d: binder_free_buf size %zd async free %zd\n",
663 alloc->pid, size, alloc->free_async_space);
664 }
665
666 binder_update_page_range(alloc, 0,
667 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
668 (void __user *)(((uintptr_t)
669 buffer->user_data + buffer_size) & PAGE_MASK));
670
671 rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
672 buffer->free = 1;
673 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
674 struct binder_buffer *next = binder_buffer_next(buffer);
675
676 if (next->free) {
677 rb_erase(&next->rb_node, &alloc->free_buffers);
678 binder_delete_free_buffer(alloc, next);
679 }
680 }
681 if (alloc->buffers.next != &buffer->entry) {
682 struct binder_buffer *prev = binder_buffer_prev(buffer);
683
684 if (prev->free) {
685 binder_delete_free_buffer(alloc, buffer);
686 rb_erase(&prev->rb_node, &alloc->free_buffers);
687 buffer = prev;
688 }
689 }
690 binder_insert_free_buffer(alloc, buffer);
691}
692
693static void binder_alloc_clear_buf(struct binder_alloc *alloc,
694 struct binder_buffer *buffer);
695/**
696 * binder_alloc_free_buf() - free a binder buffer
697 * @alloc: binder_alloc for this proc
698 * @buffer: kernel pointer to buffer
699 *
700 * Free the buffer allocated via binder_alloc_new_buf()
701 */
702void binder_alloc_free_buf(struct binder_alloc *alloc,
703 struct binder_buffer *buffer)
704{
705 /*
706 * We could eliminate the call to binder_alloc_clear_buf()
707 * from binder_alloc_deferred_release() by moving this to
708 * binder_alloc_free_buf_locked(). However, that could
709 * increase contention for the alloc mutex if clear_on_free
710 * is used frequently for large buffers. The mutex is not
711 * needed for correctness here.
712 */
713 if (buffer->clear_on_free) {
714 binder_alloc_clear_buf(alloc, buffer);
715 buffer->clear_on_free = false;
716 }
717 mutex_lock(&alloc->mutex);
718 binder_free_buf_locked(alloc, buffer);
719 mutex_unlock(&alloc->mutex);
720}
721
722/**
723 * binder_alloc_mmap_handler() - map virtual address space for proc
724 * @alloc: alloc structure for this proc
725 * @vma: vma passed to mmap()
726 *
727 * Called by binder_mmap() to initialize the space specified in
728 * vma for allocating binder buffers
729 *
730 * Return:
731 * 0 = success
732 * -EBUSY = address space already mapped
733 * -ENOMEM = failed to map memory to given address space
734 */
735int binder_alloc_mmap_handler(struct binder_alloc *alloc,
736 struct vm_area_struct *vma)
737{
738 int ret;
739 const char *failure_string;
740 struct binder_buffer *buffer;
741
742 if (unlikely(vma->vm_mm != alloc->mm)) {
743 ret = -EINVAL;
744 failure_string = "invalid vma->vm_mm";
745 goto err_invalid_mm;
746 }
747
748 mutex_lock(&binder_alloc_mmap_lock);
749 if (alloc->buffer_size) {
750 ret = -EBUSY;
751 failure_string = "already mapped";
752 goto err_already_mapped;
753 }
754 alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
755 SZ_4M);
756 mutex_unlock(&binder_alloc_mmap_lock);
757
758 alloc->buffer = (void __user *)vma->vm_start;
759
760 alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
761 sizeof(alloc->pages[0]),
762 GFP_KERNEL);
763 if (alloc->pages == NULL) {
764 ret = -ENOMEM;
765 failure_string = "alloc page array";
766 goto err_alloc_pages_failed;
767 }
768
769 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
770 if (!buffer) {
771 ret = -ENOMEM;
772 failure_string = "alloc buffer struct";
773 goto err_alloc_buf_struct_failed;
774 }
775
776 buffer->user_data = alloc->buffer;
777 list_add(&buffer->entry, &alloc->buffers);
778 buffer->free = 1;
779 binder_insert_free_buffer(alloc, buffer);
780 alloc->free_async_space = alloc->buffer_size / 2;
781 alloc->vma_addr = vma->vm_start;
782
783 return 0;
784
785err_alloc_buf_struct_failed:
786 kfree(alloc->pages);
787 alloc->pages = NULL;
788err_alloc_pages_failed:
789 alloc->buffer = NULL;
790 mutex_lock(&binder_alloc_mmap_lock);
791 alloc->buffer_size = 0;
792err_already_mapped:
793 mutex_unlock(&binder_alloc_mmap_lock);
794err_invalid_mm:
795 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
796 "%s: %d %lx-%lx %s failed %d\n", __func__,
797 alloc->pid, vma->vm_start, vma->vm_end,
798 failure_string, ret);
799 return ret;
800}
801
802
803void binder_alloc_deferred_release(struct binder_alloc *alloc)
804{
805 struct rb_node *n;
806 int buffers, page_count;
807 struct binder_buffer *buffer;
808
809 buffers = 0;
810 mutex_lock(&alloc->mutex);
811 BUG_ON(alloc->vma_addr &&
812 vma_lookup(alloc->mm, alloc->vma_addr));
813
814 while ((n = rb_first(&alloc->allocated_buffers))) {
815 buffer = rb_entry(n, struct binder_buffer, rb_node);
816
817 /* Transaction should already have been freed */
818 BUG_ON(buffer->transaction);
819
820 if (buffer->clear_on_free) {
821 binder_alloc_clear_buf(alloc, buffer);
822 buffer->clear_on_free = false;
823 }
824 binder_free_buf_locked(alloc, buffer);
825 buffers++;
826 }
827
828 while (!list_empty(&alloc->buffers)) {
829 buffer = list_first_entry(&alloc->buffers,
830 struct binder_buffer, entry);
831 WARN_ON(!buffer->free);
832
833 list_del(&buffer->entry);
834 WARN_ON_ONCE(!list_empty(&alloc->buffers));
835 kfree(buffer);
836 }
837
838 page_count = 0;
839 if (alloc->pages) {
840 int i;
841
842 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
843 void __user *page_addr;
844 bool on_lru;
845
846 if (!alloc->pages[i].page_ptr)
847 continue;
848
849 on_lru = list_lru_del(&binder_alloc_lru,
850 &alloc->pages[i].lru);
851 page_addr = alloc->buffer + i * PAGE_SIZE;
852 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
853 "%s: %d: page %d at %pK %s\n",
854 __func__, alloc->pid, i, page_addr,
855 on_lru ? "on lru" : "active");
856 __free_page(alloc->pages[i].page_ptr);
857 page_count++;
858 }
859 kfree(alloc->pages);
860 }
861 mutex_unlock(&alloc->mutex);
862 if (alloc->mm)
863 mmdrop(alloc->mm);
864
865 binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
866 "%s: %d buffers %d, pages %d\n",
867 __func__, alloc->pid, buffers, page_count);
868}
869
870static void print_binder_buffer(struct seq_file *m, const char *prefix,
871 struct binder_buffer *buffer)
872{
873 seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
874 prefix, buffer->debug_id, buffer->user_data,
875 buffer->data_size, buffer->offsets_size,
876 buffer->extra_buffers_size,
877 buffer->transaction ? "active" : "delivered");
878}
879
880/**
881 * binder_alloc_print_allocated() - print buffer info
882 * @m: seq_file for output via seq_printf()
883 * @alloc: binder_alloc for this proc
884 *
885 * Prints information about every buffer associated with
886 * the binder_alloc state to the given seq_file
887 */
888void binder_alloc_print_allocated(struct seq_file *m,
889 struct binder_alloc *alloc)
890{
891 struct rb_node *n;
892
893 mutex_lock(&alloc->mutex);
894 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
895 print_binder_buffer(m, " buffer",
896 rb_entry(n, struct binder_buffer, rb_node));
897 mutex_unlock(&alloc->mutex);
898}
899
900/**
901 * binder_alloc_print_pages() - print page usage
902 * @m: seq_file for output via seq_printf()
903 * @alloc: binder_alloc for this proc
904 */
905void binder_alloc_print_pages(struct seq_file *m,
906 struct binder_alloc *alloc)
907{
908 struct binder_lru_page *page;
909 int i;
910 int active = 0;
911 int lru = 0;
912 int free = 0;
913
914 mutex_lock(&alloc->mutex);
915 /*
916 * Make sure the binder_alloc is fully initialized, otherwise we might
917 * read inconsistent state.
918 */
919
920 mmap_read_lock(alloc->mm);
921 if (binder_alloc_get_vma(alloc) == NULL) {
922 mmap_read_unlock(alloc->mm);
923 goto uninitialized;
924 }
925
926 mmap_read_unlock(alloc->mm);
927 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
928 page = &alloc->pages[i];
929 if (!page->page_ptr)
930 free++;
931 else if (list_empty(&page->lru))
932 active++;
933 else
934 lru++;
935 }
936
937uninitialized:
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 alloc->vma_addr = 0;
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->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 return list_lru_count(&binder_alloc_lru);
1053}
1054
1055static unsigned long
1056binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1057{
1058 return list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
1059 NULL, sc->nr_to_scan);
1060}
1061
1062static struct shrinker binder_shrinker = {
1063 .count_objects = binder_shrink_count,
1064 .scan_objects = binder_shrink_scan,
1065 .seeks = DEFAULT_SEEKS,
1066};
1067
1068/**
1069 * binder_alloc_init() - called by binder_open() for per-proc initialization
1070 * @alloc: binder_alloc for this proc
1071 *
1072 * Called from binder_open() to initialize binder_alloc fields for
1073 * new binder proc
1074 */
1075void binder_alloc_init(struct binder_alloc *alloc)
1076{
1077 alloc->pid = current->group_leader->pid;
1078 alloc->mm = current->mm;
1079 mmgrab(alloc->mm);
1080 mutex_init(&alloc->mutex);
1081 INIT_LIST_HEAD(&alloc->buffers);
1082}
1083
1084int binder_alloc_shrinker_init(void)
1085{
1086 int ret = list_lru_init(&binder_alloc_lru);
1087
1088 if (ret == 0) {
1089 ret = register_shrinker(&binder_shrinker, "android-binder");
1090 if (ret)
1091 list_lru_destroy(&binder_alloc_lru);
1092 }
1093 return ret;
1094}
1095
1096/**
1097 * check_buffer() - verify that buffer/offset is safe to access
1098 * @alloc: binder_alloc for this proc
1099 * @buffer: binder buffer to be accessed
1100 * @offset: offset into @buffer data
1101 * @bytes: bytes to access from offset
1102 *
1103 * Check that the @offset/@bytes are within the size of the given
1104 * @buffer and that the buffer is currently active and not freeable.
1105 * Offsets must also be multiples of sizeof(u32). The kernel is
1106 * allowed to touch the buffer in two cases:
1107 *
1108 * 1) when the buffer is being created:
1109 * (buffer->free == 0 && buffer->allow_user_free == 0)
1110 * 2) when the buffer is being torn down:
1111 * (buffer->free == 0 && buffer->transaction == NULL).
1112 *
1113 * Return: true if the buffer is safe to access
1114 */
1115static inline bool check_buffer(struct binder_alloc *alloc,
1116 struct binder_buffer *buffer,
1117 binder_size_t offset, size_t bytes)
1118{
1119 size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1120
1121 return buffer_size >= bytes &&
1122 offset <= buffer_size - bytes &&
1123 IS_ALIGNED(offset, sizeof(u32)) &&
1124 !buffer->free &&
1125 (!buffer->allow_user_free || !buffer->transaction);
1126}
1127
1128/**
1129 * binder_alloc_get_page() - get kernel pointer for given buffer offset
1130 * @alloc: binder_alloc for this proc
1131 * @buffer: binder buffer to be accessed
1132 * @buffer_offset: offset into @buffer data
1133 * @pgoffp: address to copy final page offset to
1134 *
1135 * Lookup the struct page corresponding to the address
1136 * at @buffer_offset into @buffer->user_data. If @pgoffp is not
1137 * NULL, the byte-offset into the page is written there.
1138 *
1139 * The caller is responsible to ensure that the offset points
1140 * to a valid address within the @buffer and that @buffer is
1141 * not freeable by the user. Since it can't be freed, we are
1142 * guaranteed that the corresponding elements of @alloc->pages[]
1143 * cannot change.
1144 *
1145 * Return: struct page
1146 */
1147static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1148 struct binder_buffer *buffer,
1149 binder_size_t buffer_offset,
1150 pgoff_t *pgoffp)
1151{
1152 binder_size_t buffer_space_offset = buffer_offset +
1153 (buffer->user_data - alloc->buffer);
1154 pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
1155 size_t index = buffer_space_offset >> PAGE_SHIFT;
1156 struct binder_lru_page *lru_page;
1157
1158 lru_page = &alloc->pages[index];
1159 *pgoffp = pgoff;
1160 return lru_page->page_ptr;
1161}
1162
1163/**
1164 * binder_alloc_clear_buf() - zero out buffer
1165 * @alloc: binder_alloc for this proc
1166 * @buffer: binder buffer to be cleared
1167 *
1168 * memset the given buffer to 0
1169 */
1170static void binder_alloc_clear_buf(struct binder_alloc *alloc,
1171 struct binder_buffer *buffer)
1172{
1173 size_t bytes = binder_alloc_buffer_size(alloc, buffer);
1174 binder_size_t buffer_offset = 0;
1175
1176 while (bytes) {
1177 unsigned long size;
1178 struct page *page;
1179 pgoff_t pgoff;
1180
1181 page = binder_alloc_get_page(alloc, buffer,
1182 buffer_offset, &pgoff);
1183 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1184 memset_page(page, pgoff, 0, size);
1185 bytes -= size;
1186 buffer_offset += size;
1187 }
1188}
1189
1190/**
1191 * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1192 * @alloc: binder_alloc for this proc
1193 * @buffer: binder buffer to be accessed
1194 * @buffer_offset: offset into @buffer data
1195 * @from: userspace pointer to source buffer
1196 * @bytes: bytes to copy
1197 *
1198 * Copy bytes from source userspace to target buffer.
1199 *
1200 * Return: bytes remaining to be copied
1201 */
1202unsigned long
1203binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1204 struct binder_buffer *buffer,
1205 binder_size_t buffer_offset,
1206 const void __user *from,
1207 size_t bytes)
1208{
1209 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1210 return bytes;
1211
1212 while (bytes) {
1213 unsigned long size;
1214 unsigned long ret;
1215 struct page *page;
1216 pgoff_t pgoff;
1217 void *kptr;
1218
1219 page = binder_alloc_get_page(alloc, buffer,
1220 buffer_offset, &pgoff);
1221 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1222 kptr = kmap_local_page(page) + pgoff;
1223 ret = copy_from_user(kptr, from, size);
1224 kunmap_local(kptr);
1225 if (ret)
1226 return bytes - size + ret;
1227 bytes -= size;
1228 from += size;
1229 buffer_offset += size;
1230 }
1231 return 0;
1232}
1233
1234static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1235 bool to_buffer,
1236 struct binder_buffer *buffer,
1237 binder_size_t buffer_offset,
1238 void *ptr,
1239 size_t bytes)
1240{
1241 /* All copies must be 32-bit aligned and 32-bit size */
1242 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1243 return -EINVAL;
1244
1245 while (bytes) {
1246 unsigned long size;
1247 struct page *page;
1248 pgoff_t pgoff;
1249
1250 page = binder_alloc_get_page(alloc, buffer,
1251 buffer_offset, &pgoff);
1252 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1253 if (to_buffer)
1254 memcpy_to_page(page, pgoff, ptr, size);
1255 else
1256 memcpy_from_page(ptr, page, pgoff, size);
1257 bytes -= size;
1258 pgoff = 0;
1259 ptr = ptr + size;
1260 buffer_offset += size;
1261 }
1262 return 0;
1263}
1264
1265int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1266 struct binder_buffer *buffer,
1267 binder_size_t buffer_offset,
1268 void *src,
1269 size_t bytes)
1270{
1271 return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1272 src, bytes);
1273}
1274
1275int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1276 void *dest,
1277 struct binder_buffer *buffer,
1278 binder_size_t buffer_offset,
1279 size_t bytes)
1280{
1281 return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
1282 dest, bytes);
1283}
1284