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 
29 struct list_lru binder_alloc_lru;
30 
31 static DEFINE_MUTEX(binder_alloc_mmap_lock);
32 
33 enum {
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 };
39 static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
40 
41 module_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 
50 static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
51 {
52 	return list_entry(buffer->entry.next, struct binder_buffer, entry);
53 }
54 
55 static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
56 {
57 	return list_entry(buffer->entry.prev, struct binder_buffer, entry);
58 }
59 
60 static 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 
68 static 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 
101 static 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 
126 static 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  */
170 struct 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 
181 static 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 
278 free_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 
296 err_vm_insert_page_failed:
297 		__free_page(page->page_ptr);
298 		page->page_ptr = NULL;
299 err_alloc_page_failed:
300 err_page_ptr_cleared:
301 		if (page_addr == start)
302 			break;
303 	}
304 err_no_vma:
305 	if (mm) {
306 		mmap_read_unlock(mm);
307 		mmput(mm);
308 	}
309 	return vma ? -ENOMEM : -ESRCH;
310 }
311 
312 
313 static 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 
328 static 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 
341 static 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 
384 static 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 
553 err_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  */
576 struct 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 
592 static void __user *buffer_start_page(struct binder_buffer *buffer)
593 {
594 	return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
595 }
596 
597 static 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 
603 static 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 
652 static 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 += buffer_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 
708 static 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  */
717 void 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  */
750 int 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 
795 err_alloc_buf_struct_failed:
796 	kfree(alloc->pages);
797 	alloc->pages = NULL;
798 err_alloc_pages_failed:
799 	alloc->buffer = NULL;
800 	mutex_lock(&binder_alloc_mmap_lock);
801 	alloc->buffer_size = 0;
802 err_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 
812 void 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 
878 static 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  */
896 void 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  */
913 void 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  */
949 int 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  */
970 void 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  */
984 enum 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 
1040 err_mmap_read_lock_failed:
1041 	mmput_async(mm);
1042 err_mmget:
1043 err_page_already_freed:
1044 	mutex_unlock(&alloc->mutex);
1045 err_get_alloc_mutex_failed:
1046 	return LRU_SKIP;
1047 }
1048 
1049 static unsigned long
1050 binder_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 
1056 static unsigned long
1057 binder_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 
1066 static 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  */
1079 void 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 
1086 int 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  */
1117 static 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  */
1149 static 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  */
1172 static 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  */
1207 unsigned long
1208 binder_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 
1239 static 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 
1279 int 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 
1289 int 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 
1299