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(list: &buffer->entry, head: &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, buffer: 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(node: &new_buffer->rb_node, parent, rb_link: 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(node: &new_buffer->rb_node, parent, rb_link: 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(error: -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(lock: &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(mm: alloc->mm)) |
212 | mm = alloc->mm; |
213 | |
214 | if (mm) { |
215 | mmap_write_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, page_index: index); |
236 | |
237 | on_lru = list_lru_del(lru: &binder_alloc_lru, item: &page->lru); |
238 | WARN_ON(!on_lru); |
239 | |
240 | trace_binder_alloc_lru_end(alloc, page_index: index); |
241 | continue; |
242 | } |
243 | |
244 | if (WARN_ON(!vma)) |
245 | goto err_page_ptr_cleared; |
246 | |
247 | trace_binder_alloc_page_start(alloc, page_index: 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(list: &page->lru); |
258 | |
259 | user_page_addr = (uintptr_t)page_addr; |
260 | ret = vm_insert_page(vma, addr: 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, page_index: index); |
271 | } |
272 | if (mm) { |
273 | mmap_write_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, page_index: index); |
287 | |
288 | ret = list_lru_add(lru: &binder_alloc_lru, item: &page->lru); |
289 | WARN_ON(!ret); |
290 | |
291 | trace_binder_free_lru_end(alloc, page_index: 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_write_unlock(mm); |
307 | mmput(mm); |
308 | } |
309 | return vma ? -ENOMEM : -ESRCH; |
310 | } |
311 | |
312 | static inline void binder_alloc_set_vma(struct binder_alloc *alloc, |
313 | struct vm_area_struct *vma) |
314 | { |
315 | /* pairs with smp_load_acquire in binder_alloc_get_vma() */ |
316 | smp_store_release(&alloc->vma, vma); |
317 | } |
318 | |
319 | static inline struct vm_area_struct *binder_alloc_get_vma( |
320 | struct binder_alloc *alloc) |
321 | { |
322 | /* pairs with smp_store_release in binder_alloc_set_vma() */ |
323 | return smp_load_acquire(&alloc->vma); |
324 | } |
325 | |
326 | static bool debug_low_async_space_locked(struct binder_alloc *alloc, int pid) |
327 | { |
328 | /* |
329 | * Find the amount and size of buffers allocated by the current caller; |
330 | * The idea is that once we cross the threshold, whoever is responsible |
331 | * for the low async space is likely to try to send another async txn, |
332 | * and at some point we'll catch them in the act. This is more efficient |
333 | * than keeping a map per pid. |
334 | */ |
335 | struct rb_node *n; |
336 | struct binder_buffer *buffer; |
337 | size_t total_alloc_size = 0; |
338 | size_t num_buffers = 0; |
339 | |
340 | for (n = rb_first(&alloc->allocated_buffers); n != NULL; |
341 | n = rb_next(n)) { |
342 | buffer = rb_entry(n, struct binder_buffer, rb_node); |
343 | if (buffer->pid != pid) |
344 | continue; |
345 | if (!buffer->async_transaction) |
346 | continue; |
347 | total_alloc_size += binder_alloc_buffer_size(alloc, buffer) |
348 | + sizeof(struct binder_buffer); |
349 | num_buffers++; |
350 | } |
351 | |
352 | /* |
353 | * Warn if this pid has more than 50 transactions, or more than 50% of |
354 | * async space (which is 25% of total buffer size). Oneway spam is only |
355 | * detected when the threshold is exceeded. |
356 | */ |
357 | if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) { |
358 | binder_alloc_debug(BINDER_DEBUG_USER_ERROR, |
359 | "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n" , |
360 | alloc->pid, pid, num_buffers, total_alloc_size); |
361 | if (!alloc->oneway_spam_detected) { |
362 | alloc->oneway_spam_detected = true; |
363 | return true; |
364 | } |
365 | } |
366 | return false; |
367 | } |
368 | |
369 | static struct binder_buffer *binder_alloc_new_buf_locked( |
370 | struct binder_alloc *alloc, |
371 | size_t data_size, |
372 | size_t offsets_size, |
373 | size_t , |
374 | int is_async, |
375 | int pid) |
376 | { |
377 | struct rb_node *n = alloc->free_buffers.rb_node; |
378 | struct binder_buffer *buffer; |
379 | size_t buffer_size; |
380 | struct rb_node *best_fit = NULL; |
381 | void __user *has_page_addr; |
382 | void __user *end_page_addr; |
383 | size_t size, data_offsets_size; |
384 | int ret; |
385 | |
386 | /* Check binder_alloc is fully initialized */ |
387 | if (!binder_alloc_get_vma(alloc)) { |
388 | binder_alloc_debug(BINDER_DEBUG_USER_ERROR, |
389 | "%d: binder_alloc_buf, no vma\n" , |
390 | alloc->pid); |
391 | return ERR_PTR(error: -ESRCH); |
392 | } |
393 | |
394 | data_offsets_size = ALIGN(data_size, sizeof(void *)) + |
395 | ALIGN(offsets_size, sizeof(void *)); |
396 | |
397 | if (data_offsets_size < data_size || data_offsets_size < offsets_size) { |
398 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
399 | "%d: got transaction with invalid size %zd-%zd\n" , |
400 | alloc->pid, data_size, offsets_size); |
401 | return ERR_PTR(error: -EINVAL); |
402 | } |
403 | size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *)); |
404 | if (size < data_offsets_size || size < extra_buffers_size) { |
405 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
406 | "%d: got transaction with invalid extra_buffers_size %zd\n" , |
407 | alloc->pid, extra_buffers_size); |
408 | return ERR_PTR(error: -EINVAL); |
409 | } |
410 | if (is_async && |
411 | alloc->free_async_space < size + sizeof(struct binder_buffer)) { |
412 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
413 | "%d: binder_alloc_buf size %zd failed, no async space left\n" , |
414 | alloc->pid, size); |
415 | return ERR_PTR(error: -ENOSPC); |
416 | } |
417 | |
418 | /* Pad 0-size buffers so they get assigned unique addresses */ |
419 | size = max(size, sizeof(void *)); |
420 | |
421 | while (n) { |
422 | buffer = rb_entry(n, struct binder_buffer, rb_node); |
423 | BUG_ON(!buffer->free); |
424 | buffer_size = binder_alloc_buffer_size(alloc, buffer); |
425 | |
426 | if (size < buffer_size) { |
427 | best_fit = n; |
428 | n = n->rb_left; |
429 | } else if (size > buffer_size) |
430 | n = n->rb_right; |
431 | else { |
432 | best_fit = n; |
433 | break; |
434 | } |
435 | } |
436 | if (best_fit == NULL) { |
437 | size_t allocated_buffers = 0; |
438 | size_t largest_alloc_size = 0; |
439 | size_t total_alloc_size = 0; |
440 | size_t free_buffers = 0; |
441 | size_t largest_free_size = 0; |
442 | size_t total_free_size = 0; |
443 | |
444 | for (n = rb_first(&alloc->allocated_buffers); n != NULL; |
445 | n = rb_next(n)) { |
446 | buffer = rb_entry(n, struct binder_buffer, rb_node); |
447 | buffer_size = binder_alloc_buffer_size(alloc, buffer); |
448 | allocated_buffers++; |
449 | total_alloc_size += buffer_size; |
450 | if (buffer_size > largest_alloc_size) |
451 | largest_alloc_size = buffer_size; |
452 | } |
453 | for (n = rb_first(&alloc->free_buffers); n != NULL; |
454 | n = rb_next(n)) { |
455 | buffer = rb_entry(n, struct binder_buffer, rb_node); |
456 | buffer_size = binder_alloc_buffer_size(alloc, buffer); |
457 | free_buffers++; |
458 | total_free_size += buffer_size; |
459 | if (buffer_size > largest_free_size) |
460 | largest_free_size = buffer_size; |
461 | } |
462 | binder_alloc_debug(BINDER_DEBUG_USER_ERROR, |
463 | "%d: binder_alloc_buf size %zd failed, no address space\n" , |
464 | alloc->pid, size); |
465 | binder_alloc_debug(BINDER_DEBUG_USER_ERROR, |
466 | "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n" , |
467 | total_alloc_size, allocated_buffers, |
468 | largest_alloc_size, total_free_size, |
469 | free_buffers, largest_free_size); |
470 | return ERR_PTR(error: -ENOSPC); |
471 | } |
472 | if (n == NULL) { |
473 | buffer = rb_entry(best_fit, struct binder_buffer, rb_node); |
474 | buffer_size = binder_alloc_buffer_size(alloc, buffer); |
475 | } |
476 | |
477 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
478 | "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n" , |
479 | alloc->pid, size, buffer, buffer_size); |
480 | |
481 | has_page_addr = (void __user *) |
482 | (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK); |
483 | WARN_ON(n && buffer_size != size); |
484 | end_page_addr = |
485 | (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size); |
486 | if (end_page_addr > has_page_addr) |
487 | end_page_addr = has_page_addr; |
488 | ret = binder_update_page_range(alloc, allocate: 1, start: (void __user *) |
489 | PAGE_ALIGN((uintptr_t)buffer->user_data), end: end_page_addr); |
490 | if (ret) |
491 | return ERR_PTR(error: ret); |
492 | |
493 | if (buffer_size != size) { |
494 | struct binder_buffer *new_buffer; |
495 | |
496 | new_buffer = kzalloc(size: sizeof(*buffer), GFP_KERNEL); |
497 | if (!new_buffer) { |
498 | pr_err("%s: %d failed to alloc new buffer struct\n" , |
499 | __func__, alloc->pid); |
500 | goto err_alloc_buf_struct_failed; |
501 | } |
502 | new_buffer->user_data = (u8 __user *)buffer->user_data + size; |
503 | list_add(new: &new_buffer->entry, head: &buffer->entry); |
504 | new_buffer->free = 1; |
505 | binder_insert_free_buffer(alloc, new_buffer); |
506 | } |
507 | |
508 | rb_erase(best_fit, &alloc->free_buffers); |
509 | buffer->free = 0; |
510 | buffer->allow_user_free = 0; |
511 | binder_insert_allocated_buffer_locked(alloc, new_buffer: buffer); |
512 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
513 | "%d: binder_alloc_buf size %zd got %pK\n" , |
514 | alloc->pid, size, buffer); |
515 | buffer->data_size = data_size; |
516 | buffer->offsets_size = offsets_size; |
517 | buffer->async_transaction = is_async; |
518 | buffer->extra_buffers_size = extra_buffers_size; |
519 | buffer->pid = pid; |
520 | buffer->oneway_spam_suspect = false; |
521 | if (is_async) { |
522 | alloc->free_async_space -= size + sizeof(struct binder_buffer); |
523 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC, |
524 | "%d: binder_alloc_buf size %zd async free %zd\n" , |
525 | alloc->pid, size, alloc->free_async_space); |
526 | if (alloc->free_async_space < alloc->buffer_size / 10) { |
527 | /* |
528 | * Start detecting spammers once we have less than 20% |
529 | * of async space left (which is less than 10% of total |
530 | * buffer size). |
531 | */ |
532 | buffer->oneway_spam_suspect = debug_low_async_space_locked(alloc, pid); |
533 | } else { |
534 | alloc->oneway_spam_detected = false; |
535 | } |
536 | } |
537 | return buffer; |
538 | |
539 | err_alloc_buf_struct_failed: |
540 | binder_update_page_range(alloc, allocate: 0, start: (void __user *) |
541 | PAGE_ALIGN((uintptr_t)buffer->user_data), |
542 | end: end_page_addr); |
543 | return ERR_PTR(error: -ENOMEM); |
544 | } |
545 | |
546 | /** |
547 | * binder_alloc_new_buf() - Allocate a new binder buffer |
548 | * @alloc: binder_alloc for this proc |
549 | * @data_size: size of user data buffer |
550 | * @offsets_size: user specified buffer offset |
551 | * @extra_buffers_size: size of extra space for meta-data (eg, security context) |
552 | * @is_async: buffer for async transaction |
553 | * @pid: pid to attribute allocation to (used for debugging) |
554 | * |
555 | * Allocate a new buffer given the requested sizes. Returns |
556 | * the kernel version of the buffer pointer. The size allocated |
557 | * is the sum of the three given sizes (each rounded up to |
558 | * pointer-sized boundary) |
559 | * |
560 | * Return: The allocated buffer or %NULL if error |
561 | */ |
562 | struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc, |
563 | size_t data_size, |
564 | size_t offsets_size, |
565 | size_t , |
566 | int is_async, |
567 | int pid) |
568 | { |
569 | struct binder_buffer *buffer; |
570 | |
571 | mutex_lock(&alloc->mutex); |
572 | buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size, |
573 | extra_buffers_size, is_async, pid); |
574 | mutex_unlock(lock: &alloc->mutex); |
575 | return buffer; |
576 | } |
577 | |
578 | static void __user *buffer_start_page(struct binder_buffer *buffer) |
579 | { |
580 | return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK); |
581 | } |
582 | |
583 | static void __user *prev_buffer_end_page(struct binder_buffer *buffer) |
584 | { |
585 | return (void __user *) |
586 | (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK); |
587 | } |
588 | |
589 | static void binder_delete_free_buffer(struct binder_alloc *alloc, |
590 | struct binder_buffer *buffer) |
591 | { |
592 | struct binder_buffer *prev, *next = NULL; |
593 | bool to_free = true; |
594 | |
595 | BUG_ON(alloc->buffers.next == &buffer->entry); |
596 | prev = binder_buffer_prev(buffer); |
597 | BUG_ON(!prev->free); |
598 | if (prev_buffer_end_page(buffer: prev) == buffer_start_page(buffer)) { |
599 | to_free = false; |
600 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
601 | "%d: merge free, buffer %pK share page with %pK\n" , |
602 | alloc->pid, buffer->user_data, |
603 | prev->user_data); |
604 | } |
605 | |
606 | if (!list_is_last(list: &buffer->entry, head: &alloc->buffers)) { |
607 | next = binder_buffer_next(buffer); |
608 | if (buffer_start_page(buffer: next) == buffer_start_page(buffer)) { |
609 | to_free = false; |
610 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
611 | "%d: merge free, buffer %pK share page with %pK\n" , |
612 | alloc->pid, |
613 | buffer->user_data, |
614 | next->user_data); |
615 | } |
616 | } |
617 | |
618 | if (PAGE_ALIGNED(buffer->user_data)) { |
619 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
620 | "%d: merge free, buffer start %pK is page aligned\n" , |
621 | alloc->pid, buffer->user_data); |
622 | to_free = false; |
623 | } |
624 | |
625 | if (to_free) { |
626 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
627 | "%d: merge free, buffer %pK do not share page with %pK or %pK\n" , |
628 | alloc->pid, buffer->user_data, |
629 | prev->user_data, |
630 | next ? next->user_data : NULL); |
631 | binder_update_page_range(alloc, allocate: 0, start: buffer_start_page(buffer), |
632 | end: buffer_start_page(buffer) + PAGE_SIZE); |
633 | } |
634 | list_del(entry: &buffer->entry); |
635 | kfree(objp: buffer); |
636 | } |
637 | |
638 | static void binder_free_buf_locked(struct binder_alloc *alloc, |
639 | struct binder_buffer *buffer) |
640 | { |
641 | size_t size, buffer_size; |
642 | |
643 | buffer_size = binder_alloc_buffer_size(alloc, buffer); |
644 | |
645 | size = ALIGN(buffer->data_size, sizeof(void *)) + |
646 | ALIGN(buffer->offsets_size, sizeof(void *)) + |
647 | ALIGN(buffer->extra_buffers_size, sizeof(void *)); |
648 | |
649 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
650 | "%d: binder_free_buf %pK size %zd buffer_size %zd\n" , |
651 | alloc->pid, buffer, size, buffer_size); |
652 | |
653 | BUG_ON(buffer->free); |
654 | BUG_ON(size > buffer_size); |
655 | BUG_ON(buffer->transaction != NULL); |
656 | BUG_ON(buffer->user_data < alloc->buffer); |
657 | BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size); |
658 | |
659 | if (buffer->async_transaction) { |
660 | alloc->free_async_space += buffer_size + sizeof(struct binder_buffer); |
661 | |
662 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC, |
663 | "%d: binder_free_buf size %zd async free %zd\n" , |
664 | alloc->pid, size, alloc->free_async_space); |
665 | } |
666 | |
667 | binder_update_page_range(alloc, allocate: 0, |
668 | start: (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data), |
669 | end: (void __user *)(((uintptr_t) |
670 | buffer->user_data + buffer_size) & PAGE_MASK)); |
671 | |
672 | rb_erase(&buffer->rb_node, &alloc->allocated_buffers); |
673 | buffer->free = 1; |
674 | if (!list_is_last(list: &buffer->entry, head: &alloc->buffers)) { |
675 | struct binder_buffer *next = binder_buffer_next(buffer); |
676 | |
677 | if (next->free) { |
678 | rb_erase(&next->rb_node, &alloc->free_buffers); |
679 | binder_delete_free_buffer(alloc, buffer: next); |
680 | } |
681 | } |
682 | if (alloc->buffers.next != &buffer->entry) { |
683 | struct binder_buffer *prev = binder_buffer_prev(buffer); |
684 | |
685 | if (prev->free) { |
686 | binder_delete_free_buffer(alloc, buffer); |
687 | rb_erase(&prev->rb_node, &alloc->free_buffers); |
688 | buffer = prev; |
689 | } |
690 | } |
691 | binder_insert_free_buffer(alloc, new_buffer: buffer); |
692 | } |
693 | |
694 | static void binder_alloc_clear_buf(struct binder_alloc *alloc, |
695 | struct binder_buffer *buffer); |
696 | /** |
697 | * binder_alloc_free_buf() - free a binder buffer |
698 | * @alloc: binder_alloc for this proc |
699 | * @buffer: kernel pointer to buffer |
700 | * |
701 | * Free the buffer allocated via binder_alloc_new_buf() |
702 | */ |
703 | void binder_alloc_free_buf(struct binder_alloc *alloc, |
704 | struct binder_buffer *buffer) |
705 | { |
706 | /* |
707 | * We could eliminate the call to binder_alloc_clear_buf() |
708 | * from binder_alloc_deferred_release() by moving this to |
709 | * binder_alloc_free_buf_locked(). However, that could |
710 | * increase contention for the alloc mutex if clear_on_free |
711 | * is used frequently for large buffers. The mutex is not |
712 | * needed for correctness here. |
713 | */ |
714 | if (buffer->clear_on_free) { |
715 | binder_alloc_clear_buf(alloc, buffer); |
716 | buffer->clear_on_free = false; |
717 | } |
718 | mutex_lock(&alloc->mutex); |
719 | binder_free_buf_locked(alloc, buffer); |
720 | mutex_unlock(lock: &alloc->mutex); |
721 | } |
722 | |
723 | /** |
724 | * binder_alloc_mmap_handler() - map virtual address space for proc |
725 | * @alloc: alloc structure for this proc |
726 | * @vma: vma passed to mmap() |
727 | * |
728 | * Called by binder_mmap() to initialize the space specified in |
729 | * vma for allocating binder buffers |
730 | * |
731 | * Return: |
732 | * 0 = success |
733 | * -EBUSY = address space already mapped |
734 | * -ENOMEM = failed to map memory to given address space |
735 | */ |
736 | int binder_alloc_mmap_handler(struct binder_alloc *alloc, |
737 | struct vm_area_struct *vma) |
738 | { |
739 | int ret; |
740 | const char *failure_string; |
741 | struct binder_buffer *buffer; |
742 | |
743 | if (unlikely(vma->vm_mm != alloc->mm)) { |
744 | ret = -EINVAL; |
745 | failure_string = "invalid vma->vm_mm" ; |
746 | goto err_invalid_mm; |
747 | } |
748 | |
749 | mutex_lock(&binder_alloc_mmap_lock); |
750 | if (alloc->buffer_size) { |
751 | ret = -EBUSY; |
752 | failure_string = "already mapped" ; |
753 | goto err_already_mapped; |
754 | } |
755 | alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start, |
756 | SZ_4M); |
757 | mutex_unlock(lock: &binder_alloc_mmap_lock); |
758 | |
759 | alloc->buffer = (void __user *)vma->vm_start; |
760 | |
761 | alloc->pages = kcalloc(n: alloc->buffer_size / PAGE_SIZE, |
762 | size: sizeof(alloc->pages[0]), |
763 | GFP_KERNEL); |
764 | if (alloc->pages == NULL) { |
765 | ret = -ENOMEM; |
766 | failure_string = "alloc page array" ; |
767 | goto err_alloc_pages_failed; |
768 | } |
769 | |
770 | buffer = kzalloc(size: sizeof(*buffer), GFP_KERNEL); |
771 | if (!buffer) { |
772 | ret = -ENOMEM; |
773 | failure_string = "alloc buffer struct" ; |
774 | goto err_alloc_buf_struct_failed; |
775 | } |
776 | |
777 | buffer->user_data = alloc->buffer; |
778 | list_add(new: &buffer->entry, head: &alloc->buffers); |
779 | buffer->free = 1; |
780 | binder_insert_free_buffer(alloc, new_buffer: buffer); |
781 | alloc->free_async_space = alloc->buffer_size / 2; |
782 | |
783 | /* Signal binder_alloc is fully initialized */ |
784 | binder_alloc_set_vma(alloc, vma); |
785 | |
786 | return 0; |
787 | |
788 | err_alloc_buf_struct_failed: |
789 | kfree(objp: alloc->pages); |
790 | alloc->pages = NULL; |
791 | err_alloc_pages_failed: |
792 | alloc->buffer = NULL; |
793 | mutex_lock(&binder_alloc_mmap_lock); |
794 | alloc->buffer_size = 0; |
795 | err_already_mapped: |
796 | mutex_unlock(lock: &binder_alloc_mmap_lock); |
797 | err_invalid_mm: |
798 | binder_alloc_debug(BINDER_DEBUG_USER_ERROR, |
799 | "%s: %d %lx-%lx %s failed %d\n" , __func__, |
800 | alloc->pid, vma->vm_start, vma->vm_end, |
801 | failure_string, ret); |
802 | return ret; |
803 | } |
804 | |
805 | |
806 | void binder_alloc_deferred_release(struct binder_alloc *alloc) |
807 | { |
808 | struct rb_node *n; |
809 | int buffers, page_count; |
810 | struct binder_buffer *buffer; |
811 | |
812 | buffers = 0; |
813 | mutex_lock(&alloc->mutex); |
814 | BUG_ON(alloc->vma); |
815 | |
816 | while ((n = rb_first(&alloc->allocated_buffers))) { |
817 | buffer = rb_entry(n, struct binder_buffer, rb_node); |
818 | |
819 | /* Transaction should already have been freed */ |
820 | BUG_ON(buffer->transaction); |
821 | |
822 | if (buffer->clear_on_free) { |
823 | binder_alloc_clear_buf(alloc, buffer); |
824 | buffer->clear_on_free = false; |
825 | } |
826 | binder_free_buf_locked(alloc, buffer); |
827 | buffers++; |
828 | } |
829 | |
830 | while (!list_empty(head: &alloc->buffers)) { |
831 | buffer = list_first_entry(&alloc->buffers, |
832 | struct binder_buffer, entry); |
833 | WARN_ON(!buffer->free); |
834 | |
835 | list_del(entry: &buffer->entry); |
836 | WARN_ON_ONCE(!list_empty(&alloc->buffers)); |
837 | kfree(objp: buffer); |
838 | } |
839 | |
840 | page_count = 0; |
841 | if (alloc->pages) { |
842 | int i; |
843 | |
844 | for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) { |
845 | void __user *page_addr; |
846 | bool on_lru; |
847 | |
848 | if (!alloc->pages[i].page_ptr) |
849 | continue; |
850 | |
851 | on_lru = list_lru_del(lru: &binder_alloc_lru, |
852 | item: &alloc->pages[i].lru); |
853 | page_addr = alloc->buffer + i * PAGE_SIZE; |
854 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
855 | "%s: %d: page %d at %pK %s\n" , |
856 | __func__, alloc->pid, i, page_addr, |
857 | on_lru ? "on lru" : "active" ); |
858 | __free_page(alloc->pages[i].page_ptr); |
859 | page_count++; |
860 | } |
861 | kfree(objp: alloc->pages); |
862 | } |
863 | mutex_unlock(lock: &alloc->mutex); |
864 | if (alloc->mm) |
865 | mmdrop(mm: alloc->mm); |
866 | |
867 | binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE, |
868 | "%s: %d buffers %d, pages %d\n" , |
869 | __func__, alloc->pid, buffers, page_count); |
870 | } |
871 | |
872 | static void print_binder_buffer(struct seq_file *m, const char *prefix, |
873 | struct binder_buffer *buffer) |
874 | { |
875 | seq_printf(m, fmt: "%s %d: %pK size %zd:%zd:%zd %s\n" , |
876 | prefix, buffer->debug_id, buffer->user_data, |
877 | buffer->data_size, buffer->offsets_size, |
878 | buffer->extra_buffers_size, |
879 | buffer->transaction ? "active" : "delivered" ); |
880 | } |
881 | |
882 | /** |
883 | * binder_alloc_print_allocated() - print buffer info |
884 | * @m: seq_file for output via seq_printf() |
885 | * @alloc: binder_alloc for this proc |
886 | * |
887 | * Prints information about every buffer associated with |
888 | * the binder_alloc state to the given seq_file |
889 | */ |
890 | void binder_alloc_print_allocated(struct seq_file *m, |
891 | struct binder_alloc *alloc) |
892 | { |
893 | struct rb_node *n; |
894 | |
895 | mutex_lock(&alloc->mutex); |
896 | for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n)) |
897 | print_binder_buffer(m, prefix: " buffer" , |
898 | rb_entry(n, struct binder_buffer, rb_node)); |
899 | mutex_unlock(lock: &alloc->mutex); |
900 | } |
901 | |
902 | /** |
903 | * binder_alloc_print_pages() - print page usage |
904 | * @m: seq_file for output via seq_printf() |
905 | * @alloc: binder_alloc for this proc |
906 | */ |
907 | void binder_alloc_print_pages(struct seq_file *m, |
908 | struct binder_alloc *alloc) |
909 | { |
910 | struct binder_lru_page *page; |
911 | int i; |
912 | int active = 0; |
913 | int lru = 0; |
914 | int free = 0; |
915 | |
916 | mutex_lock(&alloc->mutex); |
917 | /* |
918 | * Make sure the binder_alloc is fully initialized, otherwise we might |
919 | * read inconsistent state. |
920 | */ |
921 | if (binder_alloc_get_vma(alloc) != NULL) { |
922 | for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) { |
923 | page = &alloc->pages[i]; |
924 | if (!page->page_ptr) |
925 | free++; |
926 | else if (list_empty(head: &page->lru)) |
927 | active++; |
928 | else |
929 | lru++; |
930 | } |
931 | } |
932 | mutex_unlock(lock: &alloc->mutex); |
933 | seq_printf(m, fmt: " pages: %d:%d:%d\n" , active, lru, free); |
934 | seq_printf(m, fmt: " pages high watermark: %zu\n" , alloc->pages_high); |
935 | } |
936 | |
937 | /** |
938 | * binder_alloc_get_allocated_count() - return count of buffers |
939 | * @alloc: binder_alloc for this proc |
940 | * |
941 | * Return: count of allocated buffers |
942 | */ |
943 | int binder_alloc_get_allocated_count(struct binder_alloc *alloc) |
944 | { |
945 | struct rb_node *n; |
946 | int count = 0; |
947 | |
948 | mutex_lock(&alloc->mutex); |
949 | for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n)) |
950 | count++; |
951 | mutex_unlock(lock: &alloc->mutex); |
952 | return count; |
953 | } |
954 | |
955 | |
956 | /** |
957 | * binder_alloc_vma_close() - invalidate address space |
958 | * @alloc: binder_alloc for this proc |
959 | * |
960 | * Called from binder_vma_close() when releasing address space. |
961 | * Clears alloc->vma to prevent new incoming transactions from |
962 | * allocating more buffers. |
963 | */ |
964 | void binder_alloc_vma_close(struct binder_alloc *alloc) |
965 | { |
966 | binder_alloc_set_vma(alloc, NULL); |
967 | } |
968 | |
969 | /** |
970 | * binder_alloc_free_page() - shrinker callback to free pages |
971 | * @item: item to free |
972 | * @lock: lock protecting the item |
973 | * @cb_arg: callback argument |
974 | * |
975 | * Called from list_lru_walk() in binder_shrink_scan() to free |
976 | * up pages when the system is under memory pressure. |
977 | */ |
978 | enum lru_status binder_alloc_free_page(struct list_head *item, |
979 | struct list_lru_one *lru, |
980 | spinlock_t *lock, |
981 | void *cb_arg) |
982 | __must_hold(lock) |
983 | { |
984 | struct mm_struct *mm = NULL; |
985 | struct binder_lru_page *page = container_of(item, |
986 | struct binder_lru_page, |
987 | lru); |
988 | struct binder_alloc *alloc; |
989 | uintptr_t page_addr; |
990 | size_t index; |
991 | struct vm_area_struct *vma; |
992 | |
993 | alloc = page->alloc; |
994 | if (!mutex_trylock(lock: &alloc->mutex)) |
995 | goto err_get_alloc_mutex_failed; |
996 | |
997 | if (!page->page_ptr) |
998 | goto err_page_already_freed; |
999 | |
1000 | index = page - alloc->pages; |
1001 | page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE; |
1002 | |
1003 | mm = alloc->mm; |
1004 | if (!mmget_not_zero(mm)) |
1005 | goto err_mmget; |
1006 | if (!mmap_read_trylock(mm)) |
1007 | goto err_mmap_read_lock_failed; |
1008 | vma = binder_alloc_get_vma(alloc); |
1009 | |
1010 | list_lru_isolate(list: lru, item); |
1011 | spin_unlock(lock); |
1012 | |
1013 | if (vma) { |
1014 | trace_binder_unmap_user_start(alloc, page_index: index); |
1015 | |
1016 | zap_page_range_single(vma, address: page_addr, PAGE_SIZE, NULL); |
1017 | |
1018 | trace_binder_unmap_user_end(alloc, page_index: index); |
1019 | } |
1020 | mmap_read_unlock(mm); |
1021 | mmput_async(mm); |
1022 | |
1023 | trace_binder_unmap_kernel_start(alloc, page_index: index); |
1024 | |
1025 | __free_page(page->page_ptr); |
1026 | page->page_ptr = NULL; |
1027 | |
1028 | trace_binder_unmap_kernel_end(alloc, page_index: index); |
1029 | |
1030 | spin_lock(lock); |
1031 | mutex_unlock(lock: &alloc->mutex); |
1032 | return LRU_REMOVED_RETRY; |
1033 | |
1034 | err_mmap_read_lock_failed: |
1035 | mmput_async(mm); |
1036 | err_mmget: |
1037 | err_page_already_freed: |
1038 | mutex_unlock(lock: &alloc->mutex); |
1039 | err_get_alloc_mutex_failed: |
1040 | return LRU_SKIP; |
1041 | } |
1042 | |
1043 | static unsigned long |
1044 | binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc) |
1045 | { |
1046 | return list_lru_count(lru: &binder_alloc_lru); |
1047 | } |
1048 | |
1049 | static unsigned long |
1050 | binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) |
1051 | { |
1052 | return list_lru_walk(lru: &binder_alloc_lru, isolate: binder_alloc_free_page, |
1053 | NULL, nr_to_walk: sc->nr_to_scan); |
1054 | } |
1055 | |
1056 | static struct shrinker *binder_shrinker; |
1057 | |
1058 | /** |
1059 | * binder_alloc_init() - called by binder_open() for per-proc initialization |
1060 | * @alloc: binder_alloc for this proc |
1061 | * |
1062 | * Called from binder_open() to initialize binder_alloc fields for |
1063 | * new binder proc |
1064 | */ |
1065 | void binder_alloc_init(struct binder_alloc *alloc) |
1066 | { |
1067 | alloc->pid = current->group_leader->pid; |
1068 | alloc->mm = current->mm; |
1069 | mmgrab(mm: alloc->mm); |
1070 | mutex_init(&alloc->mutex); |
1071 | INIT_LIST_HEAD(list: &alloc->buffers); |
1072 | } |
1073 | |
1074 | int binder_alloc_shrinker_init(void) |
1075 | { |
1076 | int ret; |
1077 | |
1078 | ret = list_lru_init(&binder_alloc_lru); |
1079 | if (ret) |
1080 | return ret; |
1081 | |
1082 | binder_shrinker = shrinker_alloc(flags: 0, fmt: "android-binder" ); |
1083 | if (!binder_shrinker) { |
1084 | list_lru_destroy(lru: &binder_alloc_lru); |
1085 | return -ENOMEM; |
1086 | } |
1087 | |
1088 | binder_shrinker->count_objects = binder_shrink_count; |
1089 | binder_shrinker->scan_objects = binder_shrink_scan; |
1090 | |
1091 | shrinker_register(shrinker: binder_shrinker); |
1092 | |
1093 | return 0; |
1094 | } |
1095 | |
1096 | void binder_alloc_shrinker_exit(void) |
1097 | { |
1098 | shrinker_free(shrinker: binder_shrinker); |
1099 | list_lru_destroy(lru: &binder_alloc_lru); |
1100 | } |
1101 | |
1102 | /** |
1103 | * check_buffer() - verify that buffer/offset is safe to access |
1104 | * @alloc: binder_alloc for this proc |
1105 | * @buffer: binder buffer to be accessed |
1106 | * @offset: offset into @buffer data |
1107 | * @bytes: bytes to access from offset |
1108 | * |
1109 | * Check that the @offset/@bytes are within the size of the given |
1110 | * @buffer and that the buffer is currently active and not freeable. |
1111 | * Offsets must also be multiples of sizeof(u32). The kernel is |
1112 | * allowed to touch the buffer in two cases: |
1113 | * |
1114 | * 1) when the buffer is being created: |
1115 | * (buffer->free == 0 && buffer->allow_user_free == 0) |
1116 | * 2) when the buffer is being torn down: |
1117 | * (buffer->free == 0 && buffer->transaction == NULL). |
1118 | * |
1119 | * Return: true if the buffer is safe to access |
1120 | */ |
1121 | static inline bool check_buffer(struct binder_alloc *alloc, |
1122 | struct binder_buffer *buffer, |
1123 | binder_size_t offset, size_t bytes) |
1124 | { |
1125 | size_t buffer_size = binder_alloc_buffer_size(alloc, buffer); |
1126 | |
1127 | return buffer_size >= bytes && |
1128 | offset <= buffer_size - bytes && |
1129 | IS_ALIGNED(offset, sizeof(u32)) && |
1130 | !buffer->free && |
1131 | (!buffer->allow_user_free || !buffer->transaction); |
1132 | } |
1133 | |
1134 | /** |
1135 | * binder_alloc_get_page() - get kernel pointer for given buffer offset |
1136 | * @alloc: binder_alloc for this proc |
1137 | * @buffer: binder buffer to be accessed |
1138 | * @buffer_offset: offset into @buffer data |
1139 | * @pgoffp: address to copy final page offset to |
1140 | * |
1141 | * Lookup the struct page corresponding to the address |
1142 | * at @buffer_offset into @buffer->user_data. If @pgoffp is not |
1143 | * NULL, the byte-offset into the page is written there. |
1144 | * |
1145 | * The caller is responsible to ensure that the offset points |
1146 | * to a valid address within the @buffer and that @buffer is |
1147 | * not freeable by the user. Since it can't be freed, we are |
1148 | * guaranteed that the corresponding elements of @alloc->pages[] |
1149 | * cannot change. |
1150 | * |
1151 | * Return: struct page |
1152 | */ |
1153 | static struct page *binder_alloc_get_page(struct binder_alloc *alloc, |
1154 | struct binder_buffer *buffer, |
1155 | binder_size_t buffer_offset, |
1156 | pgoff_t *pgoffp) |
1157 | { |
1158 | binder_size_t buffer_space_offset = buffer_offset + |
1159 | (buffer->user_data - alloc->buffer); |
1160 | pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK; |
1161 | size_t index = buffer_space_offset >> PAGE_SHIFT; |
1162 | struct binder_lru_page *lru_page; |
1163 | |
1164 | lru_page = &alloc->pages[index]; |
1165 | *pgoffp = pgoff; |
1166 | return lru_page->page_ptr; |
1167 | } |
1168 | |
1169 | /** |
1170 | * binder_alloc_clear_buf() - zero out buffer |
1171 | * @alloc: binder_alloc for this proc |
1172 | * @buffer: binder buffer to be cleared |
1173 | * |
1174 | * memset the given buffer to 0 |
1175 | */ |
1176 | static void binder_alloc_clear_buf(struct binder_alloc *alloc, |
1177 | struct binder_buffer *buffer) |
1178 | { |
1179 | size_t bytes = binder_alloc_buffer_size(alloc, buffer); |
1180 | binder_size_t buffer_offset = 0; |
1181 | |
1182 | while (bytes) { |
1183 | unsigned long size; |
1184 | struct page *page; |
1185 | pgoff_t pgoff; |
1186 | |
1187 | page = binder_alloc_get_page(alloc, buffer, |
1188 | buffer_offset, pgoffp: &pgoff); |
1189 | size = min_t(size_t, bytes, PAGE_SIZE - pgoff); |
1190 | memset_page(page, offset: pgoff, val: 0, len: size); |
1191 | bytes -= size; |
1192 | buffer_offset += size; |
1193 | } |
1194 | } |
1195 | |
1196 | /** |
1197 | * binder_alloc_copy_user_to_buffer() - copy src user to tgt user |
1198 | * @alloc: binder_alloc for this proc |
1199 | * @buffer: binder buffer to be accessed |
1200 | * @buffer_offset: offset into @buffer data |
1201 | * @from: userspace pointer to source buffer |
1202 | * @bytes: bytes to copy |
1203 | * |
1204 | * Copy bytes from source userspace to target buffer. |
1205 | * |
1206 | * Return: bytes remaining to be copied |
1207 | */ |
1208 | unsigned long |
1209 | binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc, |
1210 | struct binder_buffer *buffer, |
1211 | binder_size_t buffer_offset, |
1212 | const void __user *from, |
1213 | size_t bytes) |
1214 | { |
1215 | if (!check_buffer(alloc, buffer, offset: buffer_offset, bytes)) |
1216 | return bytes; |
1217 | |
1218 | while (bytes) { |
1219 | unsigned long size; |
1220 | unsigned long ret; |
1221 | struct page *page; |
1222 | pgoff_t pgoff; |
1223 | void *kptr; |
1224 | |
1225 | page = binder_alloc_get_page(alloc, buffer, |
1226 | buffer_offset, pgoffp: &pgoff); |
1227 | size = min_t(size_t, bytes, PAGE_SIZE - pgoff); |
1228 | kptr = kmap_local_page(page) + pgoff; |
1229 | ret = copy_from_user(to: kptr, from, n: size); |
1230 | kunmap_local(kptr); |
1231 | if (ret) |
1232 | return bytes - size + ret; |
1233 | bytes -= size; |
1234 | from += size; |
1235 | buffer_offset += size; |
1236 | } |
1237 | return 0; |
1238 | } |
1239 | |
1240 | static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc, |
1241 | bool to_buffer, |
1242 | struct binder_buffer *buffer, |
1243 | binder_size_t buffer_offset, |
1244 | void *ptr, |
1245 | size_t bytes) |
1246 | { |
1247 | /* All copies must be 32-bit aligned and 32-bit size */ |
1248 | if (!check_buffer(alloc, buffer, offset: buffer_offset, bytes)) |
1249 | return -EINVAL; |
1250 | |
1251 | while (bytes) { |
1252 | unsigned long size; |
1253 | struct page *page; |
1254 | pgoff_t pgoff; |
1255 | |
1256 | page = binder_alloc_get_page(alloc, buffer, |
1257 | buffer_offset, pgoffp: &pgoff); |
1258 | size = min_t(size_t, bytes, PAGE_SIZE - pgoff); |
1259 | if (to_buffer) |
1260 | memcpy_to_page(page, offset: pgoff, from: ptr, len: size); |
1261 | else |
1262 | memcpy_from_page(to: ptr, page, offset: pgoff, len: size); |
1263 | bytes -= size; |
1264 | pgoff = 0; |
1265 | ptr = ptr + size; |
1266 | buffer_offset += size; |
1267 | } |
1268 | return 0; |
1269 | } |
1270 | |
1271 | int binder_alloc_copy_to_buffer(struct binder_alloc *alloc, |
1272 | struct binder_buffer *buffer, |
1273 | binder_size_t buffer_offset, |
1274 | void *src, |
1275 | size_t bytes) |
1276 | { |
1277 | return binder_alloc_do_buffer_copy(alloc, to_buffer: true, buffer, buffer_offset, |
1278 | ptr: src, bytes); |
1279 | } |
1280 | |
1281 | int binder_alloc_copy_from_buffer(struct binder_alloc *alloc, |
1282 | void *dest, |
1283 | struct binder_buffer *buffer, |
1284 | binder_size_t buffer_offset, |
1285 | size_t bytes) |
1286 | { |
1287 | return binder_alloc_do_buffer_copy(alloc, to_buffer: false, buffer, buffer_offset, |
1288 | ptr: dest, bytes); |
1289 | } |
1290 | |
1291 | |