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1// SPDX-License-Identifier: GPL-2.0-only
2/* binder_alloc.c
3 *
4 * Android IPC Subsystem
5 *
6 * Copyright (C) 2007-2017 Google, Inc.
7 */
8
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11#include <linux/list.h>
12#include <linux/sched/mm.h>
13#include <linux/module.h>
14#include <linux/rtmutex.h>
15#include <linux/rbtree.h>
16#include <linux/seq_file.h>
17#include <linux/vmalloc.h>
18#include <linux/slab.h>
19#include <linux/sched.h>
20#include <linux/list_lru.h>
21#include <linux/ratelimit.h>
22#include <asm/cacheflush.h>
23#include <linux/uaccess.h>
24#include <linux/highmem.h>
25#include <linux/sizes.h>
26#include "binder_alloc.h"
27#include "binder_trace.h"
28
29struct list_lru binder_alloc_lru;
30
31static DEFINE_MUTEX(binder_alloc_mmap_lock);
32
33enum {
34 BINDER_DEBUG_USER_ERROR = 1U << 0,
35 BINDER_DEBUG_OPEN_CLOSE = 1U << 1,
36 BINDER_DEBUG_BUFFER_ALLOC = 1U << 2,
37 BINDER_DEBUG_BUFFER_ALLOC_ASYNC = 1U << 3,
38};
39static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
40
41module_param_named(debug_mask, binder_alloc_debug_mask,
42 uint, 0644);
43
44#define binder_alloc_debug(mask, x...) \
45 do { \
46 if (binder_alloc_debug_mask & mask) \
47 pr_info_ratelimited(x); \
48 } while (0)
49
50static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
51{
52 return list_entry(buffer->entry.next, struct binder_buffer, entry);
53}
54
55static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
56{
57 return list_entry(buffer->entry.prev, struct binder_buffer, entry);
58}
59
60static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
61 struct binder_buffer *buffer)
62{
63 if (list_is_last(&buffer->entry, &alloc->buffers))
64 return alloc->buffer + alloc->buffer_size - buffer->user_data;
65 return binder_buffer_next(buffer)->user_data - buffer->user_data;
66}
67
68static void binder_insert_free_buffer(struct binder_alloc *alloc,
69 struct binder_buffer *new_buffer)
70{
71 struct rb_node **p = &alloc->free_buffers.rb_node;
72 struct rb_node *parent = NULL;
73 struct binder_buffer *buffer;
74 size_t buffer_size;
75 size_t new_buffer_size;
76
77 BUG_ON(!new_buffer->free);
78
79 new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
80
81 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
82 "%d: add free buffer, size %zd, at %pK\n",
83 alloc->pid, new_buffer_size, new_buffer);
84
85 while (*p) {
86 parent = *p;
87 buffer = rb_entry(parent, struct binder_buffer, rb_node);
88 BUG_ON(!buffer->free);
89
90 buffer_size = binder_alloc_buffer_size(alloc, buffer);
91
92 if (new_buffer_size < buffer_size)
93 p = &parent->rb_left;
94 else
95 p = &parent->rb_right;
96 }
97 rb_link_node(&new_buffer->rb_node, parent, p);
98 rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
99}
100
101static void binder_insert_allocated_buffer_locked(
102 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
103{
104 struct rb_node **p = &alloc->allocated_buffers.rb_node;
105 struct rb_node *parent = NULL;
106 struct binder_buffer *buffer;
107
108 BUG_ON(new_buffer->free);
109
110 while (*p) {
111 parent = *p;
112 buffer = rb_entry(parent, struct binder_buffer, rb_node);
113 BUG_ON(buffer->free);
114
115 if (new_buffer->user_data < buffer->user_data)
116 p = &parent->rb_left;
117 else if (new_buffer->user_data > buffer->user_data)
118 p = &parent->rb_right;
119 else
120 BUG();
121 }
122 rb_link_node(&new_buffer->rb_node, parent, p);
123 rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
124}
125
126static struct binder_buffer *binder_alloc_prepare_to_free_locked(
127 struct binder_alloc *alloc,
128 uintptr_t user_ptr)
129{
130 struct rb_node *n = alloc->allocated_buffers.rb_node;
131 struct binder_buffer *buffer;
132 void __user *uptr;
133
134 uptr = (void __user *)user_ptr;
135
136 while (n) {
137 buffer = rb_entry(n, struct binder_buffer, rb_node);
138 BUG_ON(buffer->free);
139
140 if (uptr < buffer->user_data)
141 n = n->rb_left;
142 else if (uptr > buffer->user_data)
143 n = n->rb_right;
144 else {
145 /*
146 * Guard against user threads attempting to
147 * free the buffer when in use by kernel or
148 * after it's already been freed.
149 */
150 if (!buffer->allow_user_free)
151 return ERR_PTR(-EPERM);
152 buffer->allow_user_free = 0;
153 return buffer;
154 }
155 }
156 return NULL;
157}
158
159/**
160 * binder_alloc_prepare_to_free() - get buffer given user ptr
161 * @alloc: binder_alloc for this proc
162 * @user_ptr: User pointer to buffer data
163 *
164 * Validate userspace pointer to buffer data and return buffer corresponding to
165 * that user pointer. Search the rb tree for buffer that matches user data
166 * pointer.
167 *
168 * Return: Pointer to buffer or NULL
169 */
170struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
171 uintptr_t user_ptr)
172{
173 struct binder_buffer *buffer;
174
175 mutex_lock(&alloc->mutex);
176 buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
177 mutex_unlock(&alloc->mutex);
178 return buffer;
179}
180
181static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
182 void __user *start, void __user *end)
183{
184 void __user *page_addr;
185 unsigned long user_page_addr;
186 struct binder_lru_page *page;
187 struct vm_area_struct *vma = NULL;
188 struct mm_struct *mm = NULL;
189 bool need_mm = false;
190
191 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
192 "%d: %s pages %pK-%pK\n", alloc->pid,
193 allocate ? "allocate" : "free", start, end);
194
195 if (end <= start)
196 return 0;
197
198 trace_binder_update_page_range(alloc, allocate, start, end);
199
200 if (allocate == 0)
201 goto free_range;
202
203 for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
204 page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
205 if (!page->page_ptr) {
206 need_mm = true;
207 break;
208 }
209 }
210
211 if (need_mm && mmget_not_zero(alloc->vma_vm_mm))
212 mm = alloc->vma_vm_mm;
213
214 if (mm) {
215 down_read(&mm->mmap_sem);
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 /* vm_insert_page does not seem to increment the refcount */
272 }
273 if (mm) {
274 up_read(&mm->mmap_sem);
275 mmput(mm);
276 }
277 return 0;
278
279free_range:
280 for (page_addr = end - PAGE_SIZE; page_addr >= start;
281 page_addr -= PAGE_SIZE) {
282 bool ret;
283 size_t index;
284
285 index = (page_addr - alloc->buffer) / PAGE_SIZE;
286 page = &alloc->pages[index];
287
288 trace_binder_free_lru_start(alloc, index);
289
290 ret = list_lru_add(&binder_alloc_lru, &page->lru);
291 WARN_ON(!ret);
292
293 trace_binder_free_lru_end(alloc, index);
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 ;
302 }
303err_no_vma:
304 if (mm) {
305 up_read(&mm->mmap_sem);
306 mmput(mm);
307 }
308 return vma ? -ENOMEM : -ESRCH;
309}
310
311
312static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
313 struct vm_area_struct *vma)
314{
315 if (vma)
316 alloc->vma_vm_mm = vma->vm_mm;
317 /*
318 * If we see alloc->vma is not NULL, buffer data structures set up
319 * completely. Look at smp_rmb side binder_alloc_get_vma.
320 * We also want to guarantee new alloc->vma_vm_mm is always visible
321 * if alloc->vma is set.
322 */
323 smp_wmb();
324 alloc->vma = vma;
325}
326
327static inline struct vm_area_struct *binder_alloc_get_vma(
328 struct binder_alloc *alloc)
329{
330 struct vm_area_struct *vma = NULL;
331
332 if (alloc->vma) {
333 /* Look at description in binder_alloc_set_vma */
334 smp_rmb();
335 vma = alloc->vma;
336 }
337 return vma;
338}
339
340static struct binder_buffer *binder_alloc_new_buf_locked(
341 struct binder_alloc *alloc,
342 size_t data_size,
343 size_t offsets_size,
344 size_t extra_buffers_size,
345 int is_async)
346{
347 struct rb_node *n = alloc->free_buffers.rb_node;
348 struct binder_buffer *buffer;
349 size_t buffer_size;
350 struct rb_node *best_fit = NULL;
351 void __user *has_page_addr;
352 void __user *end_page_addr;
353 size_t size, data_offsets_size;
354 int ret;
355
356 if (!binder_alloc_get_vma(alloc)) {
357 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
358 "%d: binder_alloc_buf, no vma\n",
359 alloc->pid);
360 return ERR_PTR(-ESRCH);
361 }
362
363 data_offsets_size = ALIGN(data_size, sizeof(void *)) +
364 ALIGN(offsets_size, sizeof(void *));
365
366 if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
367 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
368 "%d: got transaction with invalid size %zd-%zd\n",
369 alloc->pid, data_size, offsets_size);
370 return ERR_PTR(-EINVAL);
371 }
372 size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
373 if (size < data_offsets_size || size < extra_buffers_size) {
374 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
375 "%d: got transaction with invalid extra_buffers_size %zd\n",
376 alloc->pid, extra_buffers_size);
377 return ERR_PTR(-EINVAL);
378 }
379 if (is_async &&
380 alloc->free_async_space < size + sizeof(struct binder_buffer)) {
381 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
382 "%d: binder_alloc_buf size %zd failed, no async space left\n",
383 alloc->pid, size);
384 return ERR_PTR(-ENOSPC);
385 }
386
387 /* Pad 0-size buffers so they get assigned unique addresses */
388 size = max(size, sizeof(void *));
389
390 while (n) {
391 buffer = rb_entry(n, struct binder_buffer, rb_node);
392 BUG_ON(!buffer->free);
393 buffer_size = binder_alloc_buffer_size(alloc, buffer);
394
395 if (size < buffer_size) {
396 best_fit = n;
397 n = n->rb_left;
398 } else if (size > buffer_size)
399 n = n->rb_right;
400 else {
401 best_fit = n;
402 break;
403 }
404 }
405 if (best_fit == NULL) {
406 size_t allocated_buffers = 0;
407 size_t largest_alloc_size = 0;
408 size_t total_alloc_size = 0;
409 size_t free_buffers = 0;
410 size_t largest_free_size = 0;
411 size_t total_free_size = 0;
412
413 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
414 n = rb_next(n)) {
415 buffer = rb_entry(n, struct binder_buffer, rb_node);
416 buffer_size = binder_alloc_buffer_size(alloc, buffer);
417 allocated_buffers++;
418 total_alloc_size += buffer_size;
419 if (buffer_size > largest_alloc_size)
420 largest_alloc_size = buffer_size;
421 }
422 for (n = rb_first(&alloc->free_buffers); n != NULL;
423 n = rb_next(n)) {
424 buffer = rb_entry(n, struct binder_buffer, rb_node);
425 buffer_size = binder_alloc_buffer_size(alloc, buffer);
426 free_buffers++;
427 total_free_size += buffer_size;
428 if (buffer_size > largest_free_size)
429 largest_free_size = buffer_size;
430 }
431 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
432 "%d: binder_alloc_buf size %zd failed, no address space\n",
433 alloc->pid, size);
434 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
435 "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
436 total_alloc_size, allocated_buffers,
437 largest_alloc_size, total_free_size,
438 free_buffers, largest_free_size);
439 return ERR_PTR(-ENOSPC);
440 }
441 if (n == NULL) {
442 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
443 buffer_size = binder_alloc_buffer_size(alloc, buffer);
444 }
445
446 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
447 "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
448 alloc->pid, size, buffer, buffer_size);
449
450 has_page_addr = (void __user *)
451 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
452 WARN_ON(n && buffer_size != size);
453 end_page_addr =
454 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
455 if (end_page_addr > has_page_addr)
456 end_page_addr = has_page_addr;
457 ret = binder_update_page_range(alloc, 1, (void __user *)
458 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
459 if (ret)
460 return ERR_PTR(ret);
461
462 if (buffer_size != size) {
463 struct binder_buffer *new_buffer;
464
465 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
466 if (!new_buffer) {
467 pr_err("%s: %d failed to alloc new buffer struct\n",
468 __func__, alloc->pid);
469 goto err_alloc_buf_struct_failed;
470 }
471 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
472 list_add(&new_buffer->entry, &buffer->entry);
473 new_buffer->free = 1;
474 binder_insert_free_buffer(alloc, new_buffer);
475 }
476
477 rb_erase(best_fit, &alloc->free_buffers);
478 buffer->free = 0;
479 buffer->allow_user_free = 0;
480 binder_insert_allocated_buffer_locked(alloc, buffer);
481 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
482 "%d: binder_alloc_buf size %zd got %pK\n",
483 alloc->pid, size, buffer);
484 buffer->data_size = data_size;
485 buffer->offsets_size = offsets_size;
486 buffer->async_transaction = is_async;
487 buffer->extra_buffers_size = extra_buffers_size;
488 if (is_async) {
489 alloc->free_async_space -= size + sizeof(struct binder_buffer);
490 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
491 "%d: binder_alloc_buf size %zd async free %zd\n",
492 alloc->pid, size, alloc->free_async_space);
493 }
494 return buffer;
495
496err_alloc_buf_struct_failed:
497 binder_update_page_range(alloc, 0, (void __user *)
498 PAGE_ALIGN((uintptr_t)buffer->user_data),
499 end_page_addr);
500 return ERR_PTR(-ENOMEM);
501}
502
503/**
504 * binder_alloc_new_buf() - Allocate a new binder buffer
505 * @alloc: binder_alloc for this proc
506 * @data_size: size of user data buffer
507 * @offsets_size: user specified buffer offset
508 * @extra_buffers_size: size of extra space for meta-data (eg, security context)
509 * @is_async: buffer for async transaction
510 *
511 * Allocate a new buffer given the requested sizes. Returns
512 * the kernel version of the buffer pointer. The size allocated
513 * is the sum of the three given sizes (each rounded up to
514 * pointer-sized boundary)
515 *
516 * Return: The allocated buffer or %NULL if error
517 */
518struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
519 size_t data_size,
520 size_t offsets_size,
521 size_t extra_buffers_size,
522 int is_async)
523{
524 struct binder_buffer *buffer;
525
526 mutex_lock(&alloc->mutex);
527 buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
528 extra_buffers_size, is_async);
529 mutex_unlock(&alloc->mutex);
530 return buffer;
531}
532
533static void __user *buffer_start_page(struct binder_buffer *buffer)
534{
535 return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
536}
537
538static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
539{
540 return (void __user *)
541 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
542}
543
544static void binder_delete_free_buffer(struct binder_alloc *alloc,
545 struct binder_buffer *buffer)
546{
547 struct binder_buffer *prev, *next = NULL;
548 bool to_free = true;
549 BUG_ON(alloc->buffers.next == &buffer->entry);
550 prev = binder_buffer_prev(buffer);
551 BUG_ON(!prev->free);
552 if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
553 to_free = false;
554 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
555 "%d: merge free, buffer %pK share page with %pK\n",
556 alloc->pid, buffer->user_data,
557 prev->user_data);
558 }
559
560 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
561 next = binder_buffer_next(buffer);
562 if (buffer_start_page(next) == buffer_start_page(buffer)) {
563 to_free = false;
564 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
565 "%d: merge free, buffer %pK share page with %pK\n",
566 alloc->pid,
567 buffer->user_data,
568 next->user_data);
569 }
570 }
571
572 if (PAGE_ALIGNED(buffer->user_data)) {
573 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
574 "%d: merge free, buffer start %pK is page aligned\n",
575 alloc->pid, buffer->user_data);
576 to_free = false;
577 }
578
579 if (to_free) {
580 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
581 "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
582 alloc->pid, buffer->user_data,
583 prev->user_data,
584 next ? next->user_data : NULL);
585 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
586 buffer_start_page(buffer) + PAGE_SIZE);
587 }
588 list_del(&buffer->entry);
589 kfree(buffer);
590}
591
592static void binder_free_buf_locked(struct binder_alloc *alloc,
593 struct binder_buffer *buffer)
594{
595 size_t size, buffer_size;
596
597 buffer_size = binder_alloc_buffer_size(alloc, buffer);
598
599 size = ALIGN(buffer->data_size, sizeof(void *)) +
600 ALIGN(buffer->offsets_size, sizeof(void *)) +
601 ALIGN(buffer->extra_buffers_size, sizeof(void *));
602
603 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
604 "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
605 alloc->pid, buffer, size, buffer_size);
606
607 BUG_ON(buffer->free);
608 BUG_ON(size > buffer_size);
609 BUG_ON(buffer->transaction != NULL);
610 BUG_ON(buffer->user_data < alloc->buffer);
611 BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
612
613 if (buffer->async_transaction) {
614 alloc->free_async_space += size + sizeof(struct binder_buffer);
615
616 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
617 "%d: binder_free_buf size %zd async free %zd\n",
618 alloc->pid, size, alloc->free_async_space);
619 }
620
621 binder_update_page_range(alloc, 0,
622 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
623 (void __user *)(((uintptr_t)
624 buffer->user_data + buffer_size) & PAGE_MASK));
625
626 rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
627 buffer->free = 1;
628 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
629 struct binder_buffer *next = binder_buffer_next(buffer);
630
631 if (next->free) {
632 rb_erase(&next->rb_node, &alloc->free_buffers);
633 binder_delete_free_buffer(alloc, next);
634 }
635 }
636 if (alloc->buffers.next != &buffer->entry) {
637 struct binder_buffer *prev = binder_buffer_prev(buffer);
638
639 if (prev->free) {
640 binder_delete_free_buffer(alloc, buffer);
641 rb_erase(&prev->rb_node, &alloc->free_buffers);
642 buffer = prev;
643 }
644 }
645 binder_insert_free_buffer(alloc, buffer);
646}
647
648/**
649 * binder_alloc_free_buf() - free a binder buffer
650 * @alloc: binder_alloc for this proc
651 * @buffer: kernel pointer to buffer
652 *
653 * Free the buffer allocated via binder_alloc_new_buffer()
654 */
655void binder_alloc_free_buf(struct binder_alloc *alloc,
656 struct binder_buffer *buffer)
657{
658 mutex_lock(&alloc->mutex);
659 binder_free_buf_locked(alloc, buffer);
660 mutex_unlock(&alloc->mutex);
661}
662
663/**
664 * binder_alloc_mmap_handler() - map virtual address space for proc
665 * @alloc: alloc structure for this proc
666 * @vma: vma passed to mmap()
667 *
668 * Called by binder_mmap() to initialize the space specified in
669 * vma for allocating binder buffers
670 *
671 * Return:
672 * 0 = success
673 * -EBUSY = address space already mapped
674 * -ENOMEM = failed to map memory to given address space
675 */
676int binder_alloc_mmap_handler(struct binder_alloc *alloc,
677 struct vm_area_struct *vma)
678{
679 int ret;
680 const char *failure_string;
681 struct binder_buffer *buffer;
682
683 mutex_lock(&binder_alloc_mmap_lock);
684 if (alloc->buffer) {
685 ret = -EBUSY;
686 failure_string = "already mapped";
687 goto err_already_mapped;
688 }
689
690 alloc->buffer = (void __user *)vma->vm_start;
691 mutex_unlock(&binder_alloc_mmap_lock);
692
693 alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
694 SZ_4M);
695 alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
696 sizeof(alloc->pages[0]),
697 GFP_KERNEL);
698 if (alloc->pages == NULL) {
699 ret = -ENOMEM;
700 failure_string = "alloc page array";
701 goto err_alloc_pages_failed;
702 }
703
704 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
705 if (!buffer) {
706 ret = -ENOMEM;
707 failure_string = "alloc buffer struct";
708 goto err_alloc_buf_struct_failed;
709 }
710
711 buffer->user_data = alloc->buffer;
712 list_add(&buffer->entry, &alloc->buffers);
713 buffer->free = 1;
714 binder_insert_free_buffer(alloc, buffer);
715 alloc->free_async_space = alloc->buffer_size / 2;
716 binder_alloc_set_vma(alloc, vma);
717 mmgrab(alloc->vma_vm_mm);
718
719 return 0;
720
721err_alloc_buf_struct_failed:
722 kfree(alloc->pages);
723 alloc->pages = NULL;
724err_alloc_pages_failed:
725 mutex_lock(&binder_alloc_mmap_lock);
726 alloc->buffer = NULL;
727err_already_mapped:
728 mutex_unlock(&binder_alloc_mmap_lock);
729 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
730 "%s: %d %lx-%lx %s failed %d\n", __func__,
731 alloc->pid, vma->vm_start, vma->vm_end,
732 failure_string, ret);
733 return ret;
734}
735
736
737void binder_alloc_deferred_release(struct binder_alloc *alloc)
738{
739 struct rb_node *n;
740 int buffers, page_count;
741 struct binder_buffer *buffer;
742
743 buffers = 0;
744 mutex_lock(&alloc->mutex);
745 BUG_ON(alloc->vma);
746
747 while ((n = rb_first(&alloc->allocated_buffers))) {
748 buffer = rb_entry(n, struct binder_buffer, rb_node);
749
750 /* Transaction should already have been freed */
751 BUG_ON(buffer->transaction);
752
753 binder_free_buf_locked(alloc, buffer);
754 buffers++;
755 }
756
757 while (!list_empty(&alloc->buffers)) {
758 buffer = list_first_entry(&alloc->buffers,
759 struct binder_buffer, entry);
760 WARN_ON(!buffer->free);
761
762 list_del(&buffer->entry);
763 WARN_ON_ONCE(!list_empty(&alloc->buffers));
764 kfree(buffer);
765 }
766
767 page_count = 0;
768 if (alloc->pages) {
769 int i;
770
771 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
772 void __user *page_addr;
773 bool on_lru;
774
775 if (!alloc->pages[i].page_ptr)
776 continue;
777
778 on_lru = list_lru_del(&binder_alloc_lru,
779 &alloc->pages[i].lru);
780 page_addr = alloc->buffer + i * PAGE_SIZE;
781 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
782 "%s: %d: page %d at %pK %s\n",
783 __func__, alloc->pid, i, page_addr,
784 on_lru ? "on lru" : "active");
785 __free_page(alloc->pages[i].page_ptr);
786 page_count++;
787 }
788 kfree(alloc->pages);
789 }
790 mutex_unlock(&alloc->mutex);
791 if (alloc->vma_vm_mm)
792 mmdrop(alloc->vma_vm_mm);
793
794 binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
795 "%s: %d buffers %d, pages %d\n",
796 __func__, alloc->pid, buffers, page_count);
797}
798
799static void print_binder_buffer(struct seq_file *m, const char *prefix,
800 struct binder_buffer *buffer)
801{
802 seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
803 prefix, buffer->debug_id, buffer->user_data,
804 buffer->data_size, buffer->offsets_size,
805 buffer->extra_buffers_size,
806 buffer->transaction ? "active" : "delivered");
807}
808
809/**
810 * binder_alloc_print_allocated() - print buffer info
811 * @m: seq_file for output via seq_printf()
812 * @alloc: binder_alloc for this proc
813 *
814 * Prints information about every buffer associated with
815 * the binder_alloc state to the given seq_file
816 */
817void binder_alloc_print_allocated(struct seq_file *m,
818 struct binder_alloc *alloc)
819{
820 struct rb_node *n;
821
822 mutex_lock(&alloc->mutex);
823 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
824 print_binder_buffer(m, " buffer",
825 rb_entry(n, struct binder_buffer, rb_node));
826 mutex_unlock(&alloc->mutex);
827}
828
829/**
830 * binder_alloc_print_pages() - print page usage
831 * @m: seq_file for output via seq_printf()
832 * @alloc: binder_alloc for this proc
833 */
834void binder_alloc_print_pages(struct seq_file *m,
835 struct binder_alloc *alloc)
836{
837 struct binder_lru_page *page;
838 int i;
839 int active = 0;
840 int lru = 0;
841 int free = 0;
842
843 mutex_lock(&alloc->mutex);
844 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
845 page = &alloc->pages[i];
846 if (!page->page_ptr)
847 free++;
848 else if (list_empty(&page->lru))
849 active++;
850 else
851 lru++;
852 }
853 mutex_unlock(&alloc->mutex);
854 seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
855 seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);
856}
857
858/**
859 * binder_alloc_get_allocated_count() - return count of buffers
860 * @alloc: binder_alloc for this proc
861 *
862 * Return: count of allocated buffers
863 */
864int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
865{
866 struct rb_node *n;
867 int count = 0;
868
869 mutex_lock(&alloc->mutex);
870 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
871 count++;
872 mutex_unlock(&alloc->mutex);
873 return count;
874}
875
876
877/**
878 * binder_alloc_vma_close() - invalidate address space
879 * @alloc: binder_alloc for this proc
880 *
881 * Called from binder_vma_close() when releasing address space.
882 * Clears alloc->vma to prevent new incoming transactions from
883 * allocating more buffers.
884 */
885void binder_alloc_vma_close(struct binder_alloc *alloc)
886{
887 binder_alloc_set_vma(alloc, NULL);
888}
889
890/**
891 * binder_alloc_free_page() - shrinker callback to free pages
892 * @item: item to free
893 * @lock: lock protecting the item
894 * @cb_arg: callback argument
895 *
896 * Called from list_lru_walk() in binder_shrink_scan() to free
897 * up pages when the system is under memory pressure.
898 */
899enum lru_status binder_alloc_free_page(struct list_head *item,
900 struct list_lru_one *lru,
901 spinlock_t *lock,
902 void *cb_arg)
903 __must_hold(lock)
904{
905 struct mm_struct *mm = NULL;
906 struct binder_lru_page *page = container_of(item,
907 struct binder_lru_page,
908 lru);
909 struct binder_alloc *alloc;
910 uintptr_t page_addr;
911 size_t index;
912 struct vm_area_struct *vma;
913
914 alloc = page->alloc;
915 if (!mutex_trylock(&alloc->mutex))
916 goto err_get_alloc_mutex_failed;
917
918 if (!page->page_ptr)
919 goto err_page_already_freed;
920
921 index = page - alloc->pages;
922 page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
923
924 mm = alloc->vma_vm_mm;
925 if (!mmget_not_zero(mm))
926 goto err_mmget;
927 if (!down_read_trylock(&mm->mmap_sem))
928 goto err_down_read_mmap_sem_failed;
929 vma = binder_alloc_get_vma(alloc);
930
931 list_lru_isolate(lru, item);
932 spin_unlock(lock);
933
934 if (vma) {
935 trace_binder_unmap_user_start(alloc, index);
936
937 zap_page_range(vma, page_addr, PAGE_SIZE);
938
939 trace_binder_unmap_user_end(alloc, index);
940 }
941 up_read(&mm->mmap_sem);
942 mmput(mm);
943
944 trace_binder_unmap_kernel_start(alloc, index);
945
946 __free_page(page->page_ptr);
947 page->page_ptr = NULL;
948
949 trace_binder_unmap_kernel_end(alloc, index);
950
951 spin_lock(lock);
952 mutex_unlock(&alloc->mutex);
953 return LRU_REMOVED_RETRY;
954
955err_down_read_mmap_sem_failed:
956 mmput_async(mm);
957err_mmget:
958err_page_already_freed:
959 mutex_unlock(&alloc->mutex);
960err_get_alloc_mutex_failed:
961 return LRU_SKIP;
962}
963
964static unsigned long
965binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
966{
967 unsigned long ret = list_lru_count(&binder_alloc_lru);
968 return ret;
969}
970
971static unsigned long
972binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
973{
974 unsigned long ret;
975
976 ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
977 NULL, sc->nr_to_scan);
978 return ret;
979}
980
981static struct shrinker binder_shrinker = {
982 .count_objects = binder_shrink_count,
983 .scan_objects = binder_shrink_scan,
984 .seeks = DEFAULT_SEEKS,
985};
986
987/**
988 * binder_alloc_init() - called by binder_open() for per-proc initialization
989 * @alloc: binder_alloc for this proc
990 *
991 * Called from binder_open() to initialize binder_alloc fields for
992 * new binder proc
993 */
994void binder_alloc_init(struct binder_alloc *alloc)
995{
996 alloc->pid = current->group_leader->pid;
997 mutex_init(&alloc->mutex);
998 INIT_LIST_HEAD(&alloc->buffers);
999}
1000
1001int binder_alloc_shrinker_init(void)
1002{
1003 int ret = list_lru_init(&binder_alloc_lru);
1004
1005 if (ret == 0) {
1006 ret = register_shrinker(&binder_shrinker);
1007 if (ret)
1008 list_lru_destroy(&binder_alloc_lru);
1009 }
1010 return ret;
1011}
1012
1013/**
1014 * check_buffer() - verify that buffer/offset is safe to access
1015 * @alloc: binder_alloc for this proc
1016 * @buffer: binder buffer to be accessed
1017 * @offset: offset into @buffer data
1018 * @bytes: bytes to access from offset
1019 *
1020 * Check that the @offset/@bytes are within the size of the given
1021 * @buffer and that the buffer is currently active and not freeable.
1022 * Offsets must also be multiples of sizeof(u32). The kernel is
1023 * allowed to touch the buffer in two cases:
1024 *
1025 * 1) when the buffer is being created:
1026 * (buffer->free == 0 && buffer->allow_user_free == 0)
1027 * 2) when the buffer is being torn down:
1028 * (buffer->free == 0 && buffer->transaction == NULL).
1029 *
1030 * Return: true if the buffer is safe to access
1031 */
1032static inline bool check_buffer(struct binder_alloc *alloc,
1033 struct binder_buffer *buffer,
1034 binder_size_t offset, size_t bytes)
1035{
1036 size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1037
1038 return buffer_size >= bytes &&
1039 offset <= buffer_size - bytes &&
1040 IS_ALIGNED(offset, sizeof(u32)) &&
1041 !buffer->free &&
1042 (!buffer->allow_user_free || !buffer->transaction);
1043}
1044
1045/**
1046 * binder_alloc_get_page() - get kernel pointer for given buffer offset
1047 * @alloc: binder_alloc for this proc
1048 * @buffer: binder buffer to be accessed
1049 * @buffer_offset: offset into @buffer data
1050 * @pgoffp: address to copy final page offset to
1051 *
1052 * Lookup the struct page corresponding to the address
1053 * at @buffer_offset into @buffer->user_data. If @pgoffp is not
1054 * NULL, the byte-offset into the page is written there.
1055 *
1056 * The caller is responsible to ensure that the offset points
1057 * to a valid address within the @buffer and that @buffer is
1058 * not freeable by the user. Since it can't be freed, we are
1059 * guaranteed that the corresponding elements of @alloc->pages[]
1060 * cannot change.
1061 *
1062 * Return: struct page
1063 */
1064static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1065 struct binder_buffer *buffer,
1066 binder_size_t buffer_offset,
1067 pgoff_t *pgoffp)
1068{
1069 binder_size_t buffer_space_offset = buffer_offset +
1070 (buffer->user_data - alloc->buffer);
1071 pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
1072 size_t index = buffer_space_offset >> PAGE_SHIFT;
1073 struct binder_lru_page *lru_page;
1074
1075 lru_page = &alloc->pages[index];
1076 *pgoffp = pgoff;
1077 return lru_page->page_ptr;
1078}
1079
1080/**
1081 * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1082 * @alloc: binder_alloc for this proc
1083 * @buffer: binder buffer to be accessed
1084 * @buffer_offset: offset into @buffer data
1085 * @from: userspace pointer to source buffer
1086 * @bytes: bytes to copy
1087 *
1088 * Copy bytes from source userspace to target buffer.
1089 *
1090 * Return: bytes remaining to be copied
1091 */
1092unsigned long
1093binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1094 struct binder_buffer *buffer,
1095 binder_size_t buffer_offset,
1096 const void __user *from,
1097 size_t bytes)
1098{
1099 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1100 return bytes;
1101
1102 while (bytes) {
1103 unsigned long size;
1104 unsigned long ret;
1105 struct page *page;
1106 pgoff_t pgoff;
1107 void *kptr;
1108
1109 page = binder_alloc_get_page(alloc, buffer,
1110 buffer_offset, &pgoff);
1111 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1112 kptr = kmap(page) + pgoff;
1113 ret = copy_from_user(kptr, from, size);
1114 kunmap(page);
1115 if (ret)
1116 return bytes - size + ret;
1117 bytes -= size;
1118 from += size;
1119 buffer_offset += size;
1120 }
1121 return 0;
1122}
1123
1124static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1125 bool to_buffer,
1126 struct binder_buffer *buffer,
1127 binder_size_t buffer_offset,
1128 void *ptr,
1129 size_t bytes)
1130{
1131 /* All copies must be 32-bit aligned and 32-bit size */
1132 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1133 return -EINVAL;
1134
1135 while (bytes) {
1136 unsigned long size;
1137 struct page *page;
1138 pgoff_t pgoff;
1139 void *tmpptr;
1140 void *base_ptr;
1141
1142 page = binder_alloc_get_page(alloc, buffer,
1143 buffer_offset, &pgoff);
1144 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1145 base_ptr = kmap_atomic(page);
1146 tmpptr = base_ptr + pgoff;
1147 if (to_buffer)
1148 memcpy(tmpptr, ptr, size);
1149 else
1150 memcpy(ptr, tmpptr, size);
1151 /*
1152 * kunmap_atomic() takes care of flushing the cache
1153 * if this device has VIVT cache arch
1154 */
1155 kunmap_atomic(base_ptr);
1156 bytes -= size;
1157 pgoff = 0;
1158 ptr = ptr + size;
1159 buffer_offset += size;
1160 }
1161 return 0;
1162}
1163
1164int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1165 struct binder_buffer *buffer,
1166 binder_size_t buffer_offset,
1167 void *src,
1168 size_t bytes)
1169{
1170 return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1171 src, bytes);
1172}
1173
1174int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1175 void *dest,
1176 struct binder_buffer *buffer,
1177 binder_size_t buffer_offset,
1178 size_t bytes)
1179{
1180 return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
1181 dest, bytes);
1182}
1183