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
binder_buffer_next(struct binder_buffer * buffer)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
binder_buffer_prev(struct binder_buffer * buffer)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
binder_alloc_buffer_size(struct binder_alloc * alloc,struct binder_buffer * buffer)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
binder_insert_free_buffer(struct binder_alloc * alloc,struct binder_buffer * new_buffer)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
binder_insert_allocated_buffer_locked(struct binder_alloc * alloc,struct binder_buffer * new_buffer)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
binder_alloc_prepare_to_free_locked(struct binder_alloc * alloc,uintptr_t user_ptr)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 */
binder_alloc_prepare_to_free(struct binder_alloc * alloc,uintptr_t user_ptr)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
binder_update_page_range(struct binder_alloc * alloc,int allocate,void __user * start,void __user * end)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 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
279 free_range:
280 for (page_addr = end - PAGE_SIZE; 1; page_addr -= PAGE_SIZE) {
281 bool ret;
282 size_t index;
283
284 index = (page_addr - alloc->buffer) / PAGE_SIZE;
285 page = &alloc->pages[index];
286
287 trace_binder_free_lru_start(alloc, index);
288
289 ret = list_lru_add(&binder_alloc_lru, &page->lru);
290 WARN_ON(!ret);
291
292 trace_binder_free_lru_end(alloc, index);
293 if (page_addr == start)
294 break;
295 continue;
296
297 err_vm_insert_page_failed:
298 __free_page(page->page_ptr);
299 page->page_ptr = NULL;
300 err_alloc_page_failed:
301 err_page_ptr_cleared:
302 if (page_addr == start)
303 break;
304 }
305 err_no_vma:
306 if (mm) {
307 up_read(&mm->mmap_sem);
308 mmput(mm);
309 }
310 return vma ? -ENOMEM : -ESRCH;
311 }
312
313
binder_alloc_set_vma(struct binder_alloc * alloc,struct vm_area_struct * vma)314 static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
315 struct vm_area_struct *vma)
316 {
317 if (vma)
318 alloc->vma_vm_mm = vma->vm_mm;
319 /*
320 * If we see alloc->vma is not NULL, buffer data structures set up
321 * completely. Look at smp_rmb side binder_alloc_get_vma.
322 * We also want to guarantee new alloc->vma_vm_mm is always visible
323 * if alloc->vma is set.
324 */
325 smp_wmb();
326 alloc->vma = vma;
327 }
328
binder_alloc_get_vma(struct binder_alloc * alloc)329 static inline struct vm_area_struct *binder_alloc_get_vma(
330 struct binder_alloc *alloc)
331 {
332 struct vm_area_struct *vma = NULL;
333
334 if (alloc->vma) {
335 /* Look at description in binder_alloc_set_vma */
336 smp_rmb();
337 vma = alloc->vma;
338 }
339 return vma;
340 }
341
binder_alloc_new_buf_locked(struct binder_alloc * alloc,size_t data_size,size_t offsets_size,size_t extra_buffers_size,int is_async)342 static struct binder_buffer *binder_alloc_new_buf_locked(
343 struct binder_alloc *alloc,
344 size_t data_size,
345 size_t offsets_size,
346 size_t extra_buffers_size,
347 int is_async)
348 {
349 struct rb_node *n = alloc->free_buffers.rb_node;
350 struct binder_buffer *buffer;
351 size_t buffer_size;
352 struct rb_node *best_fit = NULL;
353 void __user *has_page_addr;
354 void __user *end_page_addr;
355 size_t size, data_offsets_size;
356 int ret;
357
358 if (!binder_alloc_get_vma(alloc)) {
359 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
360 "%d: binder_alloc_buf, no vma\n",
361 alloc->pid);
362 return ERR_PTR(-ESRCH);
363 }
364
365 data_offsets_size = ALIGN(data_size, sizeof(void *)) +
366 ALIGN(offsets_size, sizeof(void *));
367
368 if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
369 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
370 "%d: got transaction with invalid size %zd-%zd\n",
371 alloc->pid, data_size, offsets_size);
372 return ERR_PTR(-EINVAL);
373 }
374 size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
375 if (size < data_offsets_size || size < extra_buffers_size) {
376 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
377 "%d: got transaction with invalid extra_buffers_size %zd\n",
378 alloc->pid, extra_buffers_size);
379 return ERR_PTR(-EINVAL);
380 }
381 if (is_async &&
382 alloc->free_async_space < size + sizeof(struct binder_buffer)) {
383 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
384 "%d: binder_alloc_buf size %zd failed, no async space left\n",
385 alloc->pid, size);
386 return ERR_PTR(-ENOSPC);
387 }
388
389 /* Pad 0-size buffers so they get assigned unique addresses */
390 size = max(size, sizeof(void *));
391
392 while (n) {
393 buffer = rb_entry(n, struct binder_buffer, rb_node);
394 BUG_ON(!buffer->free);
395 buffer_size = binder_alloc_buffer_size(alloc, buffer);
396
397 if (size < buffer_size) {
398 best_fit = n;
399 n = n->rb_left;
400 } else if (size > buffer_size)
401 n = n->rb_right;
402 else {
403 best_fit = n;
404 break;
405 }
406 }
407 if (best_fit == NULL) {
408 size_t allocated_buffers = 0;
409 size_t largest_alloc_size = 0;
410 size_t total_alloc_size = 0;
411 size_t free_buffers = 0;
412 size_t largest_free_size = 0;
413 size_t total_free_size = 0;
414
415 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
416 n = rb_next(n)) {
417 buffer = rb_entry(n, struct binder_buffer, rb_node);
418 buffer_size = binder_alloc_buffer_size(alloc, buffer);
419 allocated_buffers++;
420 total_alloc_size += buffer_size;
421 if (buffer_size > largest_alloc_size)
422 largest_alloc_size = buffer_size;
423 }
424 for (n = rb_first(&alloc->free_buffers); n != NULL;
425 n = rb_next(n)) {
426 buffer = rb_entry(n, struct binder_buffer, rb_node);
427 buffer_size = binder_alloc_buffer_size(alloc, buffer);
428 free_buffers++;
429 total_free_size += buffer_size;
430 if (buffer_size > largest_free_size)
431 largest_free_size = buffer_size;
432 }
433 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
434 "%d: binder_alloc_buf size %zd failed, no address space\n",
435 alloc->pid, size);
436 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
437 "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
438 total_alloc_size, allocated_buffers,
439 largest_alloc_size, total_free_size,
440 free_buffers, largest_free_size);
441 return ERR_PTR(-ENOSPC);
442 }
443 if (n == NULL) {
444 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
445 buffer_size = binder_alloc_buffer_size(alloc, buffer);
446 }
447
448 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
449 "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
450 alloc->pid, size, buffer, buffer_size);
451
452 has_page_addr = (void __user *)
453 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
454 WARN_ON(n && buffer_size != size);
455 end_page_addr =
456 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
457 if (end_page_addr > has_page_addr)
458 end_page_addr = has_page_addr;
459 ret = binder_update_page_range(alloc, 1, (void __user *)
460 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
461 if (ret)
462 return ERR_PTR(ret);
463
464 if (buffer_size != size) {
465 struct binder_buffer *new_buffer;
466
467 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
468 if (!new_buffer) {
469 pr_err("%s: %d failed to alloc new buffer struct\n",
470 __func__, alloc->pid);
471 goto err_alloc_buf_struct_failed;
472 }
473 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
474 list_add(&new_buffer->entry, &buffer->entry);
475 new_buffer->free = 1;
476 binder_insert_free_buffer(alloc, new_buffer);
477 }
478
479 rb_erase(best_fit, &alloc->free_buffers);
480 buffer->free = 0;
481 buffer->allow_user_free = 0;
482 binder_insert_allocated_buffer_locked(alloc, buffer);
483 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
484 "%d: binder_alloc_buf size %zd got %pK\n",
485 alloc->pid, size, buffer);
486 buffer->data_size = data_size;
487 buffer->offsets_size = offsets_size;
488 buffer->async_transaction = is_async;
489 buffer->extra_buffers_size = extra_buffers_size;
490 if (is_async) {
491 alloc->free_async_space -= size + sizeof(struct binder_buffer);
492 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
493 "%d: binder_alloc_buf size %zd async free %zd\n",
494 alloc->pid, size, alloc->free_async_space);
495 }
496 return buffer;
497
498 err_alloc_buf_struct_failed:
499 binder_update_page_range(alloc, 0, (void __user *)
500 PAGE_ALIGN((uintptr_t)buffer->user_data),
501 end_page_addr);
502 return ERR_PTR(-ENOMEM);
503 }
504
505 /**
506 * binder_alloc_new_buf() - Allocate a new binder buffer
507 * @alloc: binder_alloc for this proc
508 * @data_size: size of user data buffer
509 * @offsets_size: user specified buffer offset
510 * @extra_buffers_size: size of extra space for meta-data (eg, security context)
511 * @is_async: buffer for async transaction
512 *
513 * Allocate a new buffer given the requested sizes. Returns
514 * the kernel version of the buffer pointer. The size allocated
515 * is the sum of the three given sizes (each rounded up to
516 * pointer-sized boundary)
517 *
518 * Return: The allocated buffer or %NULL if error
519 */
binder_alloc_new_buf(struct binder_alloc * alloc,size_t data_size,size_t offsets_size,size_t extra_buffers_size,int is_async)520 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
521 size_t data_size,
522 size_t offsets_size,
523 size_t extra_buffers_size,
524 int is_async)
525 {
526 struct binder_buffer *buffer;
527
528 mutex_lock(&alloc->mutex);
529 buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
530 extra_buffers_size, is_async);
531 mutex_unlock(&alloc->mutex);
532 return buffer;
533 }
534
buffer_start_page(struct binder_buffer * buffer)535 static void __user *buffer_start_page(struct binder_buffer *buffer)
536 {
537 return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
538 }
539
prev_buffer_end_page(struct binder_buffer * buffer)540 static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
541 {
542 return (void __user *)
543 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
544 }
545
binder_delete_free_buffer(struct binder_alloc * alloc,struct binder_buffer * buffer)546 static void binder_delete_free_buffer(struct binder_alloc *alloc,
547 struct binder_buffer *buffer)
548 {
549 struct binder_buffer *prev, *next = NULL;
550 bool to_free = true;
551 BUG_ON(alloc->buffers.next == &buffer->entry);
552 prev = binder_buffer_prev(buffer);
553 BUG_ON(!prev->free);
554 if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
555 to_free = false;
556 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
557 "%d: merge free, buffer %pK share page with %pK\n",
558 alloc->pid, buffer->user_data,
559 prev->user_data);
560 }
561
562 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
563 next = binder_buffer_next(buffer);
564 if (buffer_start_page(next) == buffer_start_page(buffer)) {
565 to_free = false;
566 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
567 "%d: merge free, buffer %pK share page with %pK\n",
568 alloc->pid,
569 buffer->user_data,
570 next->user_data);
571 }
572 }
573
574 if (PAGE_ALIGNED(buffer->user_data)) {
575 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
576 "%d: merge free, buffer start %pK is page aligned\n",
577 alloc->pid, buffer->user_data);
578 to_free = false;
579 }
580
581 if (to_free) {
582 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
583 "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
584 alloc->pid, buffer->user_data,
585 prev->user_data,
586 next ? next->user_data : NULL);
587 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
588 buffer_start_page(buffer) + PAGE_SIZE);
589 }
590 list_del(&buffer->entry);
591 kfree(buffer);
592 }
593
binder_free_buf_locked(struct binder_alloc * alloc,struct binder_buffer * buffer)594 static void binder_free_buf_locked(struct binder_alloc *alloc,
595 struct binder_buffer *buffer)
596 {
597 size_t size, buffer_size;
598
599 buffer_size = binder_alloc_buffer_size(alloc, buffer);
600
601 size = ALIGN(buffer->data_size, sizeof(void *)) +
602 ALIGN(buffer->offsets_size, sizeof(void *)) +
603 ALIGN(buffer->extra_buffers_size, sizeof(void *));
604
605 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
606 "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
607 alloc->pid, buffer, size, buffer_size);
608
609 BUG_ON(buffer->free);
610 BUG_ON(size > buffer_size);
611 BUG_ON(buffer->transaction != NULL);
612 BUG_ON(buffer->user_data < alloc->buffer);
613 BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
614
615 if (buffer->async_transaction) {
616 alloc->free_async_space += size + sizeof(struct binder_buffer);
617
618 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
619 "%d: binder_free_buf size %zd async free %zd\n",
620 alloc->pid, size, alloc->free_async_space);
621 }
622
623 binder_update_page_range(alloc, 0,
624 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
625 (void __user *)(((uintptr_t)
626 buffer->user_data + buffer_size) & PAGE_MASK));
627
628 rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
629 buffer->free = 1;
630 if (!list_is_last(&buffer->entry, &alloc->buffers)) {
631 struct binder_buffer *next = binder_buffer_next(buffer);
632
633 if (next->free) {
634 rb_erase(&next->rb_node, &alloc->free_buffers);
635 binder_delete_free_buffer(alloc, next);
636 }
637 }
638 if (alloc->buffers.next != &buffer->entry) {
639 struct binder_buffer *prev = binder_buffer_prev(buffer);
640
641 if (prev->free) {
642 binder_delete_free_buffer(alloc, buffer);
643 rb_erase(&prev->rb_node, &alloc->free_buffers);
644 buffer = prev;
645 }
646 }
647 binder_insert_free_buffer(alloc, buffer);
648 }
649
650 /**
651 * binder_alloc_free_buf() - free a binder buffer
652 * @alloc: binder_alloc for this proc
653 * @buffer: kernel pointer to buffer
654 *
655 * Free the buffer allocated via binder_alloc_new_buffer()
656 */
binder_alloc_free_buf(struct binder_alloc * alloc,struct binder_buffer * buffer)657 void binder_alloc_free_buf(struct binder_alloc *alloc,
658 struct binder_buffer *buffer)
659 {
660 mutex_lock(&alloc->mutex);
661 binder_free_buf_locked(alloc, buffer);
662 mutex_unlock(&alloc->mutex);
663 }
664
665 /**
666 * binder_alloc_mmap_handler() - map virtual address space for proc
667 * @alloc: alloc structure for this proc
668 * @vma: vma passed to mmap()
669 *
670 * Called by binder_mmap() to initialize the space specified in
671 * vma for allocating binder buffers
672 *
673 * Return:
674 * 0 = success
675 * -EBUSY = address space already mapped
676 * -ENOMEM = failed to map memory to given address space
677 */
binder_alloc_mmap_handler(struct binder_alloc * alloc,struct vm_area_struct * vma)678 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
679 struct vm_area_struct *vma)
680 {
681 int ret;
682 const char *failure_string;
683 struct binder_buffer *buffer;
684
685 mutex_lock(&binder_alloc_mmap_lock);
686 if (alloc->buffer_size) {
687 ret = -EBUSY;
688 failure_string = "already mapped";
689 goto err_already_mapped;
690 }
691 alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
692 SZ_4M);
693 mutex_unlock(&binder_alloc_mmap_lock);
694
695 alloc->buffer = (void __user *)vma->vm_start;
696
697 alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
698 sizeof(alloc->pages[0]),
699 GFP_KERNEL);
700 if (alloc->pages == NULL) {
701 ret = -ENOMEM;
702 failure_string = "alloc page array";
703 goto err_alloc_pages_failed;
704 }
705
706 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
707 if (!buffer) {
708 ret = -ENOMEM;
709 failure_string = "alloc buffer struct";
710 goto err_alloc_buf_struct_failed;
711 }
712
713 buffer->user_data = alloc->buffer;
714 list_add(&buffer->entry, &alloc->buffers);
715 buffer->free = 1;
716 binder_insert_free_buffer(alloc, buffer);
717 alloc->free_async_space = alloc->buffer_size / 2;
718 binder_alloc_set_vma(alloc, vma);
719 mmgrab(alloc->vma_vm_mm);
720
721 return 0;
722
723 err_alloc_buf_struct_failed:
724 kfree(alloc->pages);
725 alloc->pages = NULL;
726 err_alloc_pages_failed:
727 alloc->buffer = NULL;
728 mutex_lock(&binder_alloc_mmap_lock);
729 alloc->buffer_size = 0;
730 err_already_mapped:
731 mutex_unlock(&binder_alloc_mmap_lock);
732 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
733 "%s: %d %lx-%lx %s failed %d\n", __func__,
734 alloc->pid, vma->vm_start, vma->vm_end,
735 failure_string, ret);
736 return ret;
737 }
738
739
binder_alloc_deferred_release(struct binder_alloc * alloc)740 void binder_alloc_deferred_release(struct binder_alloc *alloc)
741 {
742 struct rb_node *n;
743 int buffers, page_count;
744 struct binder_buffer *buffer;
745
746 buffers = 0;
747 mutex_lock(&alloc->mutex);
748 BUG_ON(alloc->vma);
749
750 while ((n = rb_first(&alloc->allocated_buffers))) {
751 buffer = rb_entry(n, struct binder_buffer, rb_node);
752
753 /* Transaction should already have been freed */
754 BUG_ON(buffer->transaction);
755
756 binder_free_buf_locked(alloc, buffer);
757 buffers++;
758 }
759
760 while (!list_empty(&alloc->buffers)) {
761 buffer = list_first_entry(&alloc->buffers,
762 struct binder_buffer, entry);
763 WARN_ON(!buffer->free);
764
765 list_del(&buffer->entry);
766 WARN_ON_ONCE(!list_empty(&alloc->buffers));
767 kfree(buffer);
768 }
769
770 page_count = 0;
771 if (alloc->pages) {
772 int i;
773
774 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
775 void __user *page_addr;
776 bool on_lru;
777
778 if (!alloc->pages[i].page_ptr)
779 continue;
780
781 on_lru = list_lru_del(&binder_alloc_lru,
782 &alloc->pages[i].lru);
783 page_addr = alloc->buffer + i * PAGE_SIZE;
784 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
785 "%s: %d: page %d at %pK %s\n",
786 __func__, alloc->pid, i, page_addr,
787 on_lru ? "on lru" : "active");
788 __free_page(alloc->pages[i].page_ptr);
789 page_count++;
790 }
791 kfree(alloc->pages);
792 }
793 mutex_unlock(&alloc->mutex);
794 if (alloc->vma_vm_mm)
795 mmdrop(alloc->vma_vm_mm);
796
797 binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
798 "%s: %d buffers %d, pages %d\n",
799 __func__, alloc->pid, buffers, page_count);
800 }
801
print_binder_buffer(struct seq_file * m,const char * prefix,struct binder_buffer * buffer)802 static void print_binder_buffer(struct seq_file *m, const char *prefix,
803 struct binder_buffer *buffer)
804 {
805 seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
806 prefix, buffer->debug_id, buffer->user_data,
807 buffer->data_size, buffer->offsets_size,
808 buffer->extra_buffers_size,
809 buffer->transaction ? "active" : "delivered");
810 }
811
812 /**
813 * binder_alloc_print_allocated() - print buffer info
814 * @m: seq_file for output via seq_printf()
815 * @alloc: binder_alloc for this proc
816 *
817 * Prints information about every buffer associated with
818 * the binder_alloc state to the given seq_file
819 */
binder_alloc_print_allocated(struct seq_file * m,struct binder_alloc * alloc)820 void binder_alloc_print_allocated(struct seq_file *m,
821 struct binder_alloc *alloc)
822 {
823 struct rb_node *n;
824
825 mutex_lock(&alloc->mutex);
826 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
827 print_binder_buffer(m, " buffer",
828 rb_entry(n, struct binder_buffer, rb_node));
829 mutex_unlock(&alloc->mutex);
830 }
831
832 /**
833 * binder_alloc_print_pages() - print page usage
834 * @m: seq_file for output via seq_printf()
835 * @alloc: binder_alloc for this proc
836 */
binder_alloc_print_pages(struct seq_file * m,struct binder_alloc * alloc)837 void binder_alloc_print_pages(struct seq_file *m,
838 struct binder_alloc *alloc)
839 {
840 struct binder_lru_page *page;
841 int i;
842 int active = 0;
843 int lru = 0;
844 int free = 0;
845
846 mutex_lock(&alloc->mutex);
847 /*
848 * Make sure the binder_alloc is fully initialized, otherwise we might
849 * read inconsistent state.
850 */
851 if (binder_alloc_get_vma(alloc) != NULL) {
852 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
853 page = &alloc->pages[i];
854 if (!page->page_ptr)
855 free++;
856 else if (list_empty(&page->lru))
857 active++;
858 else
859 lru++;
860 }
861 }
862 mutex_unlock(&alloc->mutex);
863 seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
864 seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);
865 }
866
867 /**
868 * binder_alloc_get_allocated_count() - return count of buffers
869 * @alloc: binder_alloc for this proc
870 *
871 * Return: count of allocated buffers
872 */
binder_alloc_get_allocated_count(struct binder_alloc * alloc)873 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
874 {
875 struct rb_node *n;
876 int count = 0;
877
878 mutex_lock(&alloc->mutex);
879 for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
880 count++;
881 mutex_unlock(&alloc->mutex);
882 return count;
883 }
884
885
886 /**
887 * binder_alloc_vma_close() - invalidate address space
888 * @alloc: binder_alloc for this proc
889 *
890 * Called from binder_vma_close() when releasing address space.
891 * Clears alloc->vma to prevent new incoming transactions from
892 * allocating more buffers.
893 */
binder_alloc_vma_close(struct binder_alloc * alloc)894 void binder_alloc_vma_close(struct binder_alloc *alloc)
895 {
896 binder_alloc_set_vma(alloc, NULL);
897 }
898
899 /**
900 * binder_alloc_free_page() - shrinker callback to free pages
901 * @item: item to free
902 * @lock: lock protecting the item
903 * @cb_arg: callback argument
904 *
905 * Called from list_lru_walk() in binder_shrink_scan() to free
906 * up pages when the system is under memory pressure.
907 */
binder_alloc_free_page(struct list_head * item,struct list_lru_one * lru,spinlock_t * lock,void * cb_arg)908 enum lru_status binder_alloc_free_page(struct list_head *item,
909 struct list_lru_one *lru,
910 spinlock_t *lock,
911 void *cb_arg)
912 __must_hold(lock)
913 {
914 struct mm_struct *mm = NULL;
915 struct binder_lru_page *page = container_of(item,
916 struct binder_lru_page,
917 lru);
918 struct binder_alloc *alloc;
919 uintptr_t page_addr;
920 size_t index;
921 struct vm_area_struct *vma;
922
923 alloc = page->alloc;
924 if (!mutex_trylock(&alloc->mutex))
925 goto err_get_alloc_mutex_failed;
926
927 if (!page->page_ptr)
928 goto err_page_already_freed;
929
930 index = page - alloc->pages;
931 page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
932
933 mm = alloc->vma_vm_mm;
934 if (!mmget_not_zero(mm))
935 goto err_mmget;
936 if (!down_read_trylock(&mm->mmap_sem))
937 goto err_down_read_mmap_sem_failed;
938 vma = binder_alloc_get_vma(alloc);
939
940 list_lru_isolate(lru, item);
941 spin_unlock(lock);
942
943 if (vma) {
944 trace_binder_unmap_user_start(alloc, index);
945
946 zap_page_range(vma, page_addr, PAGE_SIZE);
947
948 trace_binder_unmap_user_end(alloc, index);
949 }
950 up_read(&mm->mmap_sem);
951 mmput(mm);
952
953 trace_binder_unmap_kernel_start(alloc, index);
954
955 __free_page(page->page_ptr);
956 page->page_ptr = NULL;
957
958 trace_binder_unmap_kernel_end(alloc, index);
959
960 spin_lock(lock);
961 mutex_unlock(&alloc->mutex);
962 return LRU_REMOVED_RETRY;
963
964 err_down_read_mmap_sem_failed:
965 mmput_async(mm);
966 err_mmget:
967 err_page_already_freed:
968 mutex_unlock(&alloc->mutex);
969 err_get_alloc_mutex_failed:
970 return LRU_SKIP;
971 }
972
973 static unsigned long
binder_shrink_count(struct shrinker * shrink,struct shrink_control * sc)974 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
975 {
976 unsigned long ret = list_lru_count(&binder_alloc_lru);
977 return ret;
978 }
979
980 static unsigned long
binder_shrink_scan(struct shrinker * shrink,struct shrink_control * sc)981 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
982 {
983 unsigned long ret;
984
985 ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
986 NULL, sc->nr_to_scan);
987 return ret;
988 }
989
990 static struct shrinker binder_shrinker = {
991 .count_objects = binder_shrink_count,
992 .scan_objects = binder_shrink_scan,
993 .seeks = DEFAULT_SEEKS,
994 };
995
996 /**
997 * binder_alloc_init() - called by binder_open() for per-proc initialization
998 * @alloc: binder_alloc for this proc
999 *
1000 * Called from binder_open() to initialize binder_alloc fields for
1001 * new binder proc
1002 */
binder_alloc_init(struct binder_alloc * alloc)1003 void binder_alloc_init(struct binder_alloc *alloc)
1004 {
1005 alloc->pid = current->group_leader->pid;
1006 mutex_init(&alloc->mutex);
1007 INIT_LIST_HEAD(&alloc->buffers);
1008 }
1009
binder_alloc_shrinker_init(void)1010 int binder_alloc_shrinker_init(void)
1011 {
1012 int ret = list_lru_init(&binder_alloc_lru);
1013
1014 if (ret == 0) {
1015 ret = register_shrinker(&binder_shrinker);
1016 if (ret)
1017 list_lru_destroy(&binder_alloc_lru);
1018 }
1019 return ret;
1020 }
1021
1022 /**
1023 * check_buffer() - verify that buffer/offset is safe to access
1024 * @alloc: binder_alloc for this proc
1025 * @buffer: binder buffer to be accessed
1026 * @offset: offset into @buffer data
1027 * @bytes: bytes to access from offset
1028 *
1029 * Check that the @offset/@bytes are within the size of the given
1030 * @buffer and that the buffer is currently active and not freeable.
1031 * Offsets must also be multiples of sizeof(u32). The kernel is
1032 * allowed to touch the buffer in two cases:
1033 *
1034 * 1) when the buffer is being created:
1035 * (buffer->free == 0 && buffer->allow_user_free == 0)
1036 * 2) when the buffer is being torn down:
1037 * (buffer->free == 0 && buffer->transaction == NULL).
1038 *
1039 * Return: true if the buffer is safe to access
1040 */
check_buffer(struct binder_alloc * alloc,struct binder_buffer * buffer,binder_size_t offset,size_t bytes)1041 static inline bool check_buffer(struct binder_alloc *alloc,
1042 struct binder_buffer *buffer,
1043 binder_size_t offset, size_t bytes)
1044 {
1045 size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1046
1047 return buffer_size >= bytes &&
1048 offset <= buffer_size - bytes &&
1049 IS_ALIGNED(offset, sizeof(u32)) &&
1050 !buffer->free &&
1051 (!buffer->allow_user_free || !buffer->transaction);
1052 }
1053
1054 /**
1055 * binder_alloc_get_page() - get kernel pointer for given buffer offset
1056 * @alloc: binder_alloc for this proc
1057 * @buffer: binder buffer to be accessed
1058 * @buffer_offset: offset into @buffer data
1059 * @pgoffp: address to copy final page offset to
1060 *
1061 * Lookup the struct page corresponding to the address
1062 * at @buffer_offset into @buffer->user_data. If @pgoffp is not
1063 * NULL, the byte-offset into the page is written there.
1064 *
1065 * The caller is responsible to ensure that the offset points
1066 * to a valid address within the @buffer and that @buffer is
1067 * not freeable by the user. Since it can't be freed, we are
1068 * guaranteed that the corresponding elements of @alloc->pages[]
1069 * cannot change.
1070 *
1071 * Return: struct page
1072 */
binder_alloc_get_page(struct binder_alloc * alloc,struct binder_buffer * buffer,binder_size_t buffer_offset,pgoff_t * pgoffp)1073 static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1074 struct binder_buffer *buffer,
1075 binder_size_t buffer_offset,
1076 pgoff_t *pgoffp)
1077 {
1078 binder_size_t buffer_space_offset = buffer_offset +
1079 (buffer->user_data - alloc->buffer);
1080 pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
1081 size_t index = buffer_space_offset >> PAGE_SHIFT;
1082 struct binder_lru_page *lru_page;
1083
1084 lru_page = &alloc->pages[index];
1085 *pgoffp = pgoff;
1086 return lru_page->page_ptr;
1087 }
1088
1089 /**
1090 * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1091 * @alloc: binder_alloc for this proc
1092 * @buffer: binder buffer to be accessed
1093 * @buffer_offset: offset into @buffer data
1094 * @from: userspace pointer to source buffer
1095 * @bytes: bytes to copy
1096 *
1097 * Copy bytes from source userspace to target buffer.
1098 *
1099 * Return: bytes remaining to be copied
1100 */
1101 unsigned long
binder_alloc_copy_user_to_buffer(struct binder_alloc * alloc,struct binder_buffer * buffer,binder_size_t buffer_offset,const void __user * from,size_t bytes)1102 binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1103 struct binder_buffer *buffer,
1104 binder_size_t buffer_offset,
1105 const void __user *from,
1106 size_t bytes)
1107 {
1108 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1109 return bytes;
1110
1111 while (bytes) {
1112 unsigned long size;
1113 unsigned long ret;
1114 struct page *page;
1115 pgoff_t pgoff;
1116 void *kptr;
1117
1118 page = binder_alloc_get_page(alloc, buffer,
1119 buffer_offset, &pgoff);
1120 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1121 kptr = kmap(page) + pgoff;
1122 ret = copy_from_user(kptr, from, size);
1123 kunmap(page);
1124 if (ret)
1125 return bytes - size + ret;
1126 bytes -= size;
1127 from += size;
1128 buffer_offset += size;
1129 }
1130 return 0;
1131 }
1132
binder_alloc_do_buffer_copy(struct binder_alloc * alloc,bool to_buffer,struct binder_buffer * buffer,binder_size_t buffer_offset,void * ptr,size_t bytes)1133 static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1134 bool to_buffer,
1135 struct binder_buffer *buffer,
1136 binder_size_t buffer_offset,
1137 void *ptr,
1138 size_t bytes)
1139 {
1140 /* All copies must be 32-bit aligned and 32-bit size */
1141 if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1142 return -EINVAL;
1143
1144 while (bytes) {
1145 unsigned long size;
1146 struct page *page;
1147 pgoff_t pgoff;
1148 void *tmpptr;
1149 void *base_ptr;
1150
1151 page = binder_alloc_get_page(alloc, buffer,
1152 buffer_offset, &pgoff);
1153 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1154 base_ptr = kmap_atomic(page);
1155 tmpptr = base_ptr + pgoff;
1156 if (to_buffer)
1157 memcpy(tmpptr, ptr, size);
1158 else
1159 memcpy(ptr, tmpptr, size);
1160 /*
1161 * kunmap_atomic() takes care of flushing the cache
1162 * if this device has VIVT cache arch
1163 */
1164 kunmap_atomic(base_ptr);
1165 bytes -= size;
1166 pgoff = 0;
1167 ptr = ptr + size;
1168 buffer_offset += size;
1169 }
1170 return 0;
1171 }
1172
binder_alloc_copy_to_buffer(struct binder_alloc * alloc,struct binder_buffer * buffer,binder_size_t buffer_offset,void * src,size_t bytes)1173 int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1174 struct binder_buffer *buffer,
1175 binder_size_t buffer_offset,
1176 void *src,
1177 size_t bytes)
1178 {
1179 return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1180 src, bytes);
1181 }
1182
binder_alloc_copy_from_buffer(struct binder_alloc * alloc,void * dest,struct binder_buffer * buffer,binder_size_t buffer_offset,size_t bytes)1183 int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1184 void *dest,
1185 struct binder_buffer *buffer,
1186 binder_size_t buffer_offset,
1187 size_t bytes)
1188 {
1189 return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
1190 dest, bytes);
1191 }
1192
1193