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_freelist; |
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 | unsigned long user_ptr) |
129 | { |
130 | struct rb_node *n = alloc->allocated_buffers.rb_node; |
131 | struct binder_buffer *buffer; |
132 | |
133 | while (n) { |
134 | buffer = rb_entry(n, struct binder_buffer, rb_node); |
135 | BUG_ON(buffer->free); |
136 | |
137 | if (user_ptr < buffer->user_data) { |
138 | n = n->rb_left; |
139 | } else if (user_ptr > buffer->user_data) { |
140 | n = n->rb_right; |
141 | } else { |
142 | /* |
143 | * Guard against user threads attempting to |
144 | * free the buffer when in use by kernel or |
145 | * after it's already been freed. |
146 | */ |
147 | if (!buffer->allow_user_free) |
148 | return ERR_PTR(error: -EPERM); |
149 | buffer->allow_user_free = 0; |
150 | return buffer; |
151 | } |
152 | } |
153 | return NULL; |
154 | } |
155 | |
156 | /** |
157 | * binder_alloc_prepare_to_free() - get buffer given user ptr |
158 | * @alloc: binder_alloc for this proc |
159 | * @user_ptr: User pointer to buffer data |
160 | * |
161 | * Validate userspace pointer to buffer data and return buffer corresponding to |
162 | * that user pointer. Search the rb tree for buffer that matches user data |
163 | * pointer. |
164 | * |
165 | * Return: Pointer to buffer or NULL |
166 | */ |
167 | struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc, |
168 | unsigned long user_ptr) |
169 | { |
170 | struct binder_buffer *buffer; |
171 | |
172 | spin_lock(lock: &alloc->lock); |
173 | buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr); |
174 | spin_unlock(lock: &alloc->lock); |
175 | return buffer; |
176 | } |
177 | |
178 | static inline void |
179 | binder_set_installed_page(struct binder_lru_page *lru_page, |
180 | struct page *page) |
181 | { |
182 | /* Pairs with acquire in binder_get_installed_page() */ |
183 | smp_store_release(&lru_page->page_ptr, page); |
184 | } |
185 | |
186 | static inline struct page * |
187 | binder_get_installed_page(struct binder_lru_page *lru_page) |
188 | { |
189 | /* Pairs with release in binder_set_installed_page() */ |
190 | return smp_load_acquire(&lru_page->page_ptr); |
191 | } |
192 | |
193 | static void binder_lru_freelist_add(struct binder_alloc *alloc, |
194 | unsigned long start, unsigned long end) |
195 | { |
196 | struct binder_lru_page *page; |
197 | unsigned long page_addr; |
198 | |
199 | trace_binder_update_page_range(alloc, allocate: false, start, end); |
200 | |
201 | for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) { |
202 | size_t index; |
203 | int ret; |
204 | |
205 | index = (page_addr - alloc->buffer) / PAGE_SIZE; |
206 | page = &alloc->pages[index]; |
207 | |
208 | if (!binder_get_installed_page(lru_page: page)) |
209 | continue; |
210 | |
211 | trace_binder_free_lru_start(alloc, page_index: index); |
212 | |
213 | ret = list_lru_add_obj(lru: &binder_freelist, item: &page->lru); |
214 | WARN_ON(!ret); |
215 | |
216 | trace_binder_free_lru_end(alloc, page_index: index); |
217 | } |
218 | } |
219 | |
220 | static int binder_install_single_page(struct binder_alloc *alloc, |
221 | struct binder_lru_page *lru_page, |
222 | unsigned long addr) |
223 | { |
224 | struct page *page; |
225 | int ret = 0; |
226 | |
227 | if (!mmget_not_zero(mm: alloc->mm)) |
228 | return -ESRCH; |
229 | |
230 | /* |
231 | * Protected with mmap_sem in write mode as multiple tasks |
232 | * might race to install the same page. |
233 | */ |
234 | mmap_write_lock(mm: alloc->mm); |
235 | if (binder_get_installed_page(lru_page)) |
236 | goto out; |
237 | |
238 | if (!alloc->vma) { |
239 | pr_err("%d: %s failed, no vma\n" , alloc->pid, __func__); |
240 | ret = -ESRCH; |
241 | goto out; |
242 | } |
243 | |
244 | page = alloc_page(GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO); |
245 | if (!page) { |
246 | pr_err("%d: failed to allocate page\n" , alloc->pid); |
247 | ret = -ENOMEM; |
248 | goto out; |
249 | } |
250 | |
251 | ret = vm_insert_page(alloc->vma, addr, page); |
252 | if (ret) { |
253 | pr_err("%d: %s failed to insert page at offset %lx with %d\n" , |
254 | alloc->pid, __func__, addr - alloc->buffer, ret); |
255 | __free_page(page); |
256 | ret = -ENOMEM; |
257 | goto out; |
258 | } |
259 | |
260 | /* Mark page installation complete and safe to use */ |
261 | binder_set_installed_page(lru_page, page); |
262 | out: |
263 | mmap_write_unlock(mm: alloc->mm); |
264 | mmput_async(alloc->mm); |
265 | return ret; |
266 | } |
267 | |
268 | static int binder_install_buffer_pages(struct binder_alloc *alloc, |
269 | struct binder_buffer *buffer, |
270 | size_t size) |
271 | { |
272 | struct binder_lru_page *page; |
273 | unsigned long start, final; |
274 | unsigned long page_addr; |
275 | |
276 | start = buffer->user_data & PAGE_MASK; |
277 | final = PAGE_ALIGN(buffer->user_data + size); |
278 | |
279 | for (page_addr = start; page_addr < final; page_addr += PAGE_SIZE) { |
280 | unsigned long index; |
281 | int ret; |
282 | |
283 | index = (page_addr - alloc->buffer) / PAGE_SIZE; |
284 | page = &alloc->pages[index]; |
285 | |
286 | if (binder_get_installed_page(lru_page: page)) |
287 | continue; |
288 | |
289 | trace_binder_alloc_page_start(alloc, page_index: index); |
290 | |
291 | ret = binder_install_single_page(alloc, lru_page: page, addr: page_addr); |
292 | if (ret) |
293 | return ret; |
294 | |
295 | trace_binder_alloc_page_end(alloc, page_index: index); |
296 | } |
297 | |
298 | return 0; |
299 | } |
300 | |
301 | /* The range of pages should exclude those shared with other buffers */ |
302 | static void binder_lru_freelist_del(struct binder_alloc *alloc, |
303 | unsigned long start, unsigned long end) |
304 | { |
305 | struct binder_lru_page *page; |
306 | unsigned long page_addr; |
307 | |
308 | trace_binder_update_page_range(alloc, allocate: true, start, end); |
309 | |
310 | for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) { |
311 | unsigned long index; |
312 | bool on_lru; |
313 | |
314 | index = (page_addr - alloc->buffer) / PAGE_SIZE; |
315 | page = &alloc->pages[index]; |
316 | |
317 | if (page->page_ptr) { |
318 | trace_binder_alloc_lru_start(alloc, page_index: index); |
319 | |
320 | on_lru = list_lru_del_obj(lru: &binder_freelist, item: &page->lru); |
321 | WARN_ON(!on_lru); |
322 | |
323 | trace_binder_alloc_lru_end(alloc, page_index: index); |
324 | continue; |
325 | } |
326 | |
327 | if (index + 1 > alloc->pages_high) |
328 | alloc->pages_high = index + 1; |
329 | } |
330 | } |
331 | |
332 | static inline void binder_alloc_set_vma(struct binder_alloc *alloc, |
333 | struct vm_area_struct *vma) |
334 | { |
335 | /* pairs with smp_load_acquire in binder_alloc_get_vma() */ |
336 | smp_store_release(&alloc->vma, vma); |
337 | } |
338 | |
339 | static inline struct vm_area_struct *binder_alloc_get_vma( |
340 | struct binder_alloc *alloc) |
341 | { |
342 | /* pairs with smp_store_release in binder_alloc_set_vma() */ |
343 | return smp_load_acquire(&alloc->vma); |
344 | } |
345 | |
346 | static void debug_no_space_locked(struct binder_alloc *alloc) |
347 | { |
348 | size_t largest_alloc_size = 0; |
349 | struct binder_buffer *buffer; |
350 | size_t allocated_buffers = 0; |
351 | size_t largest_free_size = 0; |
352 | size_t total_alloc_size = 0; |
353 | size_t total_free_size = 0; |
354 | size_t free_buffers = 0; |
355 | size_t buffer_size; |
356 | struct rb_node *n; |
357 | |
358 | for (n = rb_first(&alloc->allocated_buffers); n; n = rb_next(n)) { |
359 | buffer = rb_entry(n, struct binder_buffer, rb_node); |
360 | buffer_size = binder_alloc_buffer_size(alloc, buffer); |
361 | allocated_buffers++; |
362 | total_alloc_size += buffer_size; |
363 | if (buffer_size > largest_alloc_size) |
364 | largest_alloc_size = buffer_size; |
365 | } |
366 | |
367 | for (n = rb_first(&alloc->free_buffers); n; n = rb_next(n)) { |
368 | buffer = rb_entry(n, struct binder_buffer, rb_node); |
369 | buffer_size = binder_alloc_buffer_size(alloc, buffer); |
370 | free_buffers++; |
371 | total_free_size += buffer_size; |
372 | if (buffer_size > largest_free_size) |
373 | largest_free_size = buffer_size; |
374 | } |
375 | |
376 | binder_alloc_debug(BINDER_DEBUG_USER_ERROR, |
377 | "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n" , |
378 | total_alloc_size, allocated_buffers, |
379 | largest_alloc_size, total_free_size, |
380 | free_buffers, largest_free_size); |
381 | } |
382 | |
383 | static bool debug_low_async_space_locked(struct binder_alloc *alloc) |
384 | { |
385 | /* |
386 | * Find the amount and size of buffers allocated by the current caller; |
387 | * The idea is that once we cross the threshold, whoever is responsible |
388 | * for the low async space is likely to try to send another async txn, |
389 | * and at some point we'll catch them in the act. This is more efficient |
390 | * than keeping a map per pid. |
391 | */ |
392 | struct binder_buffer *buffer; |
393 | size_t total_alloc_size = 0; |
394 | int pid = current->tgid; |
395 | size_t num_buffers = 0; |
396 | struct rb_node *n; |
397 | |
398 | /* |
399 | * Only start detecting spammers once we have less than 20% of async |
400 | * space left (which is less than 10% of total buffer size). |
401 | */ |
402 | if (alloc->free_async_space >= alloc->buffer_size / 10) { |
403 | alloc->oneway_spam_detected = false; |
404 | return false; |
405 | } |
406 | |
407 | for (n = rb_first(&alloc->allocated_buffers); n != NULL; |
408 | n = rb_next(n)) { |
409 | buffer = rb_entry(n, struct binder_buffer, rb_node); |
410 | if (buffer->pid != pid) |
411 | continue; |
412 | if (!buffer->async_transaction) |
413 | continue; |
414 | total_alloc_size += binder_alloc_buffer_size(alloc, buffer); |
415 | num_buffers++; |
416 | } |
417 | |
418 | /* |
419 | * Warn if this pid has more than 50 transactions, or more than 50% of |
420 | * async space (which is 25% of total buffer size). Oneway spam is only |
421 | * detected when the threshold is exceeded. |
422 | */ |
423 | if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) { |
424 | binder_alloc_debug(BINDER_DEBUG_USER_ERROR, |
425 | "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n" , |
426 | alloc->pid, pid, num_buffers, total_alloc_size); |
427 | if (!alloc->oneway_spam_detected) { |
428 | alloc->oneway_spam_detected = true; |
429 | return true; |
430 | } |
431 | } |
432 | return false; |
433 | } |
434 | |
435 | /* Callers preallocate @new_buffer, it is freed by this function if unused */ |
436 | static struct binder_buffer *binder_alloc_new_buf_locked( |
437 | struct binder_alloc *alloc, |
438 | struct binder_buffer *new_buffer, |
439 | size_t size, |
440 | int is_async) |
441 | { |
442 | struct rb_node *n = alloc->free_buffers.rb_node; |
443 | struct rb_node *best_fit = NULL; |
444 | struct binder_buffer *buffer; |
445 | unsigned long next_used_page; |
446 | unsigned long curr_last_page; |
447 | size_t buffer_size; |
448 | |
449 | if (is_async && alloc->free_async_space < size) { |
450 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
451 | "%d: binder_alloc_buf size %zd failed, no async space left\n" , |
452 | alloc->pid, size); |
453 | buffer = ERR_PTR(error: -ENOSPC); |
454 | goto out; |
455 | } |
456 | |
457 | while (n) { |
458 | buffer = rb_entry(n, struct binder_buffer, rb_node); |
459 | BUG_ON(!buffer->free); |
460 | buffer_size = binder_alloc_buffer_size(alloc, buffer); |
461 | |
462 | if (size < buffer_size) { |
463 | best_fit = n; |
464 | n = n->rb_left; |
465 | } else if (size > buffer_size) { |
466 | n = n->rb_right; |
467 | } else { |
468 | best_fit = n; |
469 | break; |
470 | } |
471 | } |
472 | |
473 | if (unlikely(!best_fit)) { |
474 | binder_alloc_debug(BINDER_DEBUG_USER_ERROR, |
475 | "%d: binder_alloc_buf size %zd failed, no address space\n" , |
476 | alloc->pid, size); |
477 | debug_no_space_locked(alloc); |
478 | buffer = ERR_PTR(error: -ENOSPC); |
479 | goto out; |
480 | } |
481 | |
482 | if (buffer_size != size) { |
483 | /* Found an oversized buffer and needs to be split */ |
484 | buffer = rb_entry(best_fit, struct binder_buffer, rb_node); |
485 | buffer_size = binder_alloc_buffer_size(alloc, buffer); |
486 | |
487 | WARN_ON(n || buffer_size == size); |
488 | new_buffer->user_data = buffer->user_data + size; |
489 | list_add(new: &new_buffer->entry, head: &buffer->entry); |
490 | new_buffer->free = 1; |
491 | binder_insert_free_buffer(alloc, new_buffer); |
492 | new_buffer = NULL; |
493 | } |
494 | |
495 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
496 | "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n" , |
497 | alloc->pid, size, buffer, buffer_size); |
498 | |
499 | /* |
500 | * Now we remove the pages from the freelist. A clever calculation |
501 | * with buffer_size determines if the last page is shared with an |
502 | * adjacent in-use buffer. In such case, the page has been already |
503 | * removed from the freelist so we trim our range short. |
504 | */ |
505 | next_used_page = (buffer->user_data + buffer_size) & PAGE_MASK; |
506 | curr_last_page = PAGE_ALIGN(buffer->user_data + size); |
507 | binder_lru_freelist_del(alloc, PAGE_ALIGN(buffer->user_data), |
508 | min(next_used_page, curr_last_page)); |
509 | |
510 | rb_erase(&buffer->rb_node, &alloc->free_buffers); |
511 | buffer->free = 0; |
512 | buffer->allow_user_free = 0; |
513 | binder_insert_allocated_buffer_locked(alloc, new_buffer: buffer); |
514 | buffer->async_transaction = is_async; |
515 | buffer->oneway_spam_suspect = false; |
516 | if (is_async) { |
517 | alloc->free_async_space -= size; |
518 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC, |
519 | "%d: binder_alloc_buf size %zd async free %zd\n" , |
520 | alloc->pid, size, alloc->free_async_space); |
521 | if (debug_low_async_space_locked(alloc)) |
522 | buffer->oneway_spam_suspect = true; |
523 | } |
524 | |
525 | out: |
526 | /* Discard possibly unused new_buffer */ |
527 | kfree(objp: new_buffer); |
528 | return buffer; |
529 | } |
530 | |
531 | /* Calculate the sanitized total size, returns 0 for invalid request */ |
532 | static inline size_t sanitized_size(size_t data_size, |
533 | size_t offsets_size, |
534 | size_t ) |
535 | { |
536 | size_t total, tmp; |
537 | |
538 | /* Align to pointer size and check for overflows */ |
539 | tmp = ALIGN(data_size, sizeof(void *)) + |
540 | ALIGN(offsets_size, sizeof(void *)); |
541 | if (tmp < data_size || tmp < offsets_size) |
542 | return 0; |
543 | total = tmp + ALIGN(extra_buffers_size, sizeof(void *)); |
544 | if (total < tmp || total < extra_buffers_size) |
545 | return 0; |
546 | |
547 | /* Pad 0-sized buffers so they get a unique address */ |
548 | total = max(total, sizeof(void *)); |
549 | |
550 | return total; |
551 | } |
552 | |
553 | /** |
554 | * binder_alloc_new_buf() - Allocate a new binder buffer |
555 | * @alloc: binder_alloc for this proc |
556 | * @data_size: size of user data buffer |
557 | * @offsets_size: user specified buffer offset |
558 | * @extra_buffers_size: size of extra space for meta-data (eg, security context) |
559 | * @is_async: buffer for async transaction |
560 | * |
561 | * Allocate a new buffer given the requested sizes. Returns |
562 | * the kernel version of the buffer pointer. The size allocated |
563 | * is the sum of the three given sizes (each rounded up to |
564 | * pointer-sized boundary) |
565 | * |
566 | * Return: The allocated buffer or %ERR_PTR(-errno) if error |
567 | */ |
568 | struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc, |
569 | size_t data_size, |
570 | size_t offsets_size, |
571 | size_t , |
572 | int is_async) |
573 | { |
574 | struct binder_buffer *buffer, *next; |
575 | size_t size; |
576 | int ret; |
577 | |
578 | /* Check binder_alloc is fully initialized */ |
579 | if (!binder_alloc_get_vma(alloc)) { |
580 | binder_alloc_debug(BINDER_DEBUG_USER_ERROR, |
581 | "%d: binder_alloc_buf, no vma\n" , |
582 | alloc->pid); |
583 | return ERR_PTR(error: -ESRCH); |
584 | } |
585 | |
586 | size = sanitized_size(data_size, offsets_size, extra_buffers_size); |
587 | if (unlikely(!size)) { |
588 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
589 | "%d: got transaction with invalid size %zd-%zd-%zd\n" , |
590 | alloc->pid, data_size, offsets_size, |
591 | extra_buffers_size); |
592 | return ERR_PTR(error: -EINVAL); |
593 | } |
594 | |
595 | /* Preallocate the next buffer */ |
596 | next = kzalloc(size: sizeof(*next), GFP_KERNEL); |
597 | if (!next) |
598 | return ERR_PTR(error: -ENOMEM); |
599 | |
600 | spin_lock(lock: &alloc->lock); |
601 | buffer = binder_alloc_new_buf_locked(alloc, new_buffer: next, size, is_async); |
602 | if (IS_ERR(ptr: buffer)) { |
603 | spin_unlock(lock: &alloc->lock); |
604 | goto out; |
605 | } |
606 | |
607 | buffer->data_size = data_size; |
608 | buffer->offsets_size = offsets_size; |
609 | buffer->extra_buffers_size = extra_buffers_size; |
610 | buffer->pid = current->tgid; |
611 | spin_unlock(lock: &alloc->lock); |
612 | |
613 | ret = binder_install_buffer_pages(alloc, buffer, size); |
614 | if (ret) { |
615 | binder_alloc_free_buf(alloc, buffer); |
616 | buffer = ERR_PTR(error: ret); |
617 | } |
618 | out: |
619 | return buffer; |
620 | } |
621 | |
622 | static unsigned long buffer_start_page(struct binder_buffer *buffer) |
623 | { |
624 | return buffer->user_data & PAGE_MASK; |
625 | } |
626 | |
627 | static unsigned long prev_buffer_end_page(struct binder_buffer *buffer) |
628 | { |
629 | return (buffer->user_data - 1) & PAGE_MASK; |
630 | } |
631 | |
632 | static void binder_delete_free_buffer(struct binder_alloc *alloc, |
633 | struct binder_buffer *buffer) |
634 | { |
635 | struct binder_buffer *prev, *next; |
636 | |
637 | if (PAGE_ALIGNED(buffer->user_data)) |
638 | goto skip_freelist; |
639 | |
640 | BUG_ON(alloc->buffers.next == &buffer->entry); |
641 | prev = binder_buffer_prev(buffer); |
642 | BUG_ON(!prev->free); |
643 | if (prev_buffer_end_page(buffer: prev) == buffer_start_page(buffer)) |
644 | goto skip_freelist; |
645 | |
646 | if (!list_is_last(list: &buffer->entry, head: &alloc->buffers)) { |
647 | next = binder_buffer_next(buffer); |
648 | if (buffer_start_page(buffer: next) == buffer_start_page(buffer)) |
649 | goto skip_freelist; |
650 | } |
651 | |
652 | binder_lru_freelist_add(alloc, start: buffer_start_page(buffer), |
653 | end: buffer_start_page(buffer) + PAGE_SIZE); |
654 | skip_freelist: |
655 | list_del(entry: &buffer->entry); |
656 | kfree(objp: buffer); |
657 | } |
658 | |
659 | static void binder_free_buf_locked(struct binder_alloc *alloc, |
660 | struct binder_buffer *buffer) |
661 | { |
662 | size_t size, buffer_size; |
663 | |
664 | buffer_size = binder_alloc_buffer_size(alloc, buffer); |
665 | |
666 | size = ALIGN(buffer->data_size, sizeof(void *)) + |
667 | ALIGN(buffer->offsets_size, sizeof(void *)) + |
668 | ALIGN(buffer->extra_buffers_size, sizeof(void *)); |
669 | |
670 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
671 | "%d: binder_free_buf %pK size %zd buffer_size %zd\n" , |
672 | alloc->pid, buffer, size, buffer_size); |
673 | |
674 | BUG_ON(buffer->free); |
675 | BUG_ON(size > buffer_size); |
676 | BUG_ON(buffer->transaction != NULL); |
677 | BUG_ON(buffer->user_data < alloc->buffer); |
678 | BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size); |
679 | |
680 | if (buffer->async_transaction) { |
681 | alloc->free_async_space += buffer_size; |
682 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC, |
683 | "%d: binder_free_buf size %zd async free %zd\n" , |
684 | alloc->pid, size, alloc->free_async_space); |
685 | } |
686 | |
687 | binder_lru_freelist_add(alloc, PAGE_ALIGN(buffer->user_data), |
688 | end: (buffer->user_data + buffer_size) & PAGE_MASK); |
689 | |
690 | rb_erase(&buffer->rb_node, &alloc->allocated_buffers); |
691 | buffer->free = 1; |
692 | if (!list_is_last(list: &buffer->entry, head: &alloc->buffers)) { |
693 | struct binder_buffer *next = binder_buffer_next(buffer); |
694 | |
695 | if (next->free) { |
696 | rb_erase(&next->rb_node, &alloc->free_buffers); |
697 | binder_delete_free_buffer(alloc, buffer: next); |
698 | } |
699 | } |
700 | if (alloc->buffers.next != &buffer->entry) { |
701 | struct binder_buffer *prev = binder_buffer_prev(buffer); |
702 | |
703 | if (prev->free) { |
704 | binder_delete_free_buffer(alloc, buffer); |
705 | rb_erase(&prev->rb_node, &alloc->free_buffers); |
706 | buffer = prev; |
707 | } |
708 | } |
709 | binder_insert_free_buffer(alloc, new_buffer: buffer); |
710 | } |
711 | |
712 | /** |
713 | * binder_alloc_get_page() - get kernel pointer for given buffer offset |
714 | * @alloc: binder_alloc for this proc |
715 | * @buffer: binder buffer to be accessed |
716 | * @buffer_offset: offset into @buffer data |
717 | * @pgoffp: address to copy final page offset to |
718 | * |
719 | * Lookup the struct page corresponding to the address |
720 | * at @buffer_offset into @buffer->user_data. If @pgoffp is not |
721 | * NULL, the byte-offset into the page is written there. |
722 | * |
723 | * The caller is responsible to ensure that the offset points |
724 | * to a valid address within the @buffer and that @buffer is |
725 | * not freeable by the user. Since it can't be freed, we are |
726 | * guaranteed that the corresponding elements of @alloc->pages[] |
727 | * cannot change. |
728 | * |
729 | * Return: struct page |
730 | */ |
731 | static struct page *binder_alloc_get_page(struct binder_alloc *alloc, |
732 | struct binder_buffer *buffer, |
733 | binder_size_t buffer_offset, |
734 | pgoff_t *pgoffp) |
735 | { |
736 | binder_size_t buffer_space_offset = buffer_offset + |
737 | (buffer->user_data - alloc->buffer); |
738 | pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK; |
739 | size_t index = buffer_space_offset >> PAGE_SHIFT; |
740 | struct binder_lru_page *lru_page; |
741 | |
742 | lru_page = &alloc->pages[index]; |
743 | *pgoffp = pgoff; |
744 | return lru_page->page_ptr; |
745 | } |
746 | |
747 | /** |
748 | * binder_alloc_clear_buf() - zero out buffer |
749 | * @alloc: binder_alloc for this proc |
750 | * @buffer: binder buffer to be cleared |
751 | * |
752 | * memset the given buffer to 0 |
753 | */ |
754 | static void binder_alloc_clear_buf(struct binder_alloc *alloc, |
755 | struct binder_buffer *buffer) |
756 | { |
757 | size_t bytes = binder_alloc_buffer_size(alloc, buffer); |
758 | binder_size_t buffer_offset = 0; |
759 | |
760 | while (bytes) { |
761 | unsigned long size; |
762 | struct page *page; |
763 | pgoff_t pgoff; |
764 | |
765 | page = binder_alloc_get_page(alloc, buffer, |
766 | buffer_offset, pgoffp: &pgoff); |
767 | size = min_t(size_t, bytes, PAGE_SIZE - pgoff); |
768 | memset_page(page, offset: pgoff, val: 0, len: size); |
769 | bytes -= size; |
770 | buffer_offset += size; |
771 | } |
772 | } |
773 | |
774 | /** |
775 | * binder_alloc_free_buf() - free a binder buffer |
776 | * @alloc: binder_alloc for this proc |
777 | * @buffer: kernel pointer to buffer |
778 | * |
779 | * Free the buffer allocated via binder_alloc_new_buf() |
780 | */ |
781 | void binder_alloc_free_buf(struct binder_alloc *alloc, |
782 | struct binder_buffer *buffer) |
783 | { |
784 | /* |
785 | * We could eliminate the call to binder_alloc_clear_buf() |
786 | * from binder_alloc_deferred_release() by moving this to |
787 | * binder_free_buf_locked(). However, that could |
788 | * increase contention for the alloc->lock if clear_on_free |
789 | * is used frequently for large buffers. This lock is not |
790 | * needed for correctness here. |
791 | */ |
792 | if (buffer->clear_on_free) { |
793 | binder_alloc_clear_buf(alloc, buffer); |
794 | buffer->clear_on_free = false; |
795 | } |
796 | spin_lock(lock: &alloc->lock); |
797 | binder_free_buf_locked(alloc, buffer); |
798 | spin_unlock(lock: &alloc->lock); |
799 | } |
800 | |
801 | /** |
802 | * binder_alloc_mmap_handler() - map virtual address space for proc |
803 | * @alloc: alloc structure for this proc |
804 | * @vma: vma passed to mmap() |
805 | * |
806 | * Called by binder_mmap() to initialize the space specified in |
807 | * vma for allocating binder buffers |
808 | * |
809 | * Return: |
810 | * 0 = success |
811 | * -EBUSY = address space already mapped |
812 | * -ENOMEM = failed to map memory to given address space |
813 | */ |
814 | int binder_alloc_mmap_handler(struct binder_alloc *alloc, |
815 | struct vm_area_struct *vma) |
816 | { |
817 | struct binder_buffer *buffer; |
818 | const char *failure_string; |
819 | int ret, i; |
820 | |
821 | if (unlikely(vma->vm_mm != alloc->mm)) { |
822 | ret = -EINVAL; |
823 | failure_string = "invalid vma->vm_mm" ; |
824 | goto err_invalid_mm; |
825 | } |
826 | |
827 | mutex_lock(&binder_alloc_mmap_lock); |
828 | if (alloc->buffer_size) { |
829 | ret = -EBUSY; |
830 | failure_string = "already mapped" ; |
831 | goto err_already_mapped; |
832 | } |
833 | alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start, |
834 | SZ_4M); |
835 | mutex_unlock(lock: &binder_alloc_mmap_lock); |
836 | |
837 | alloc->buffer = vma->vm_start; |
838 | |
839 | alloc->pages = kcalloc(n: alloc->buffer_size / PAGE_SIZE, |
840 | size: sizeof(alloc->pages[0]), |
841 | GFP_KERNEL); |
842 | if (alloc->pages == NULL) { |
843 | ret = -ENOMEM; |
844 | failure_string = "alloc page array" ; |
845 | goto err_alloc_pages_failed; |
846 | } |
847 | |
848 | for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) { |
849 | alloc->pages[i].alloc = alloc; |
850 | INIT_LIST_HEAD(list: &alloc->pages[i].lru); |
851 | } |
852 | |
853 | buffer = kzalloc(size: sizeof(*buffer), GFP_KERNEL); |
854 | if (!buffer) { |
855 | ret = -ENOMEM; |
856 | failure_string = "alloc buffer struct" ; |
857 | goto err_alloc_buf_struct_failed; |
858 | } |
859 | |
860 | buffer->user_data = alloc->buffer; |
861 | list_add(new: &buffer->entry, head: &alloc->buffers); |
862 | buffer->free = 1; |
863 | binder_insert_free_buffer(alloc, new_buffer: buffer); |
864 | alloc->free_async_space = alloc->buffer_size / 2; |
865 | |
866 | /* Signal binder_alloc is fully initialized */ |
867 | binder_alloc_set_vma(alloc, vma); |
868 | |
869 | return 0; |
870 | |
871 | err_alloc_buf_struct_failed: |
872 | kfree(objp: alloc->pages); |
873 | alloc->pages = NULL; |
874 | err_alloc_pages_failed: |
875 | alloc->buffer = 0; |
876 | mutex_lock(&binder_alloc_mmap_lock); |
877 | alloc->buffer_size = 0; |
878 | err_already_mapped: |
879 | mutex_unlock(lock: &binder_alloc_mmap_lock); |
880 | err_invalid_mm: |
881 | binder_alloc_debug(BINDER_DEBUG_USER_ERROR, |
882 | "%s: %d %lx-%lx %s failed %d\n" , __func__, |
883 | alloc->pid, vma->vm_start, vma->vm_end, |
884 | failure_string, ret); |
885 | return ret; |
886 | } |
887 | |
888 | |
889 | void binder_alloc_deferred_release(struct binder_alloc *alloc) |
890 | { |
891 | struct rb_node *n; |
892 | int buffers, page_count; |
893 | struct binder_buffer *buffer; |
894 | |
895 | buffers = 0; |
896 | spin_lock(lock: &alloc->lock); |
897 | BUG_ON(alloc->vma); |
898 | |
899 | while ((n = rb_first(&alloc->allocated_buffers))) { |
900 | buffer = rb_entry(n, struct binder_buffer, rb_node); |
901 | |
902 | /* Transaction should already have been freed */ |
903 | BUG_ON(buffer->transaction); |
904 | |
905 | if (buffer->clear_on_free) { |
906 | binder_alloc_clear_buf(alloc, buffer); |
907 | buffer->clear_on_free = false; |
908 | } |
909 | binder_free_buf_locked(alloc, buffer); |
910 | buffers++; |
911 | } |
912 | |
913 | while (!list_empty(head: &alloc->buffers)) { |
914 | buffer = list_first_entry(&alloc->buffers, |
915 | struct binder_buffer, entry); |
916 | WARN_ON(!buffer->free); |
917 | |
918 | list_del(entry: &buffer->entry); |
919 | WARN_ON_ONCE(!list_empty(&alloc->buffers)); |
920 | kfree(objp: buffer); |
921 | } |
922 | |
923 | page_count = 0; |
924 | if (alloc->pages) { |
925 | int i; |
926 | |
927 | for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) { |
928 | bool on_lru; |
929 | |
930 | if (!alloc->pages[i].page_ptr) |
931 | continue; |
932 | |
933 | on_lru = list_lru_del_obj(lru: &binder_freelist, |
934 | item: &alloc->pages[i].lru); |
935 | binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
936 | "%s: %d: page %d %s\n" , |
937 | __func__, alloc->pid, i, |
938 | on_lru ? "on lru" : "active" ); |
939 | __free_page(alloc->pages[i].page_ptr); |
940 | page_count++; |
941 | } |
942 | kfree(objp: alloc->pages); |
943 | } |
944 | spin_unlock(lock: &alloc->lock); |
945 | if (alloc->mm) |
946 | mmdrop(mm: alloc->mm); |
947 | |
948 | binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE, |
949 | "%s: %d buffers %d, pages %d\n" , |
950 | __func__, alloc->pid, buffers, page_count); |
951 | } |
952 | |
953 | /** |
954 | * binder_alloc_print_allocated() - print buffer info |
955 | * @m: seq_file for output via seq_printf() |
956 | * @alloc: binder_alloc for this proc |
957 | * |
958 | * Prints information about every buffer associated with |
959 | * the binder_alloc state to the given seq_file |
960 | */ |
961 | void binder_alloc_print_allocated(struct seq_file *m, |
962 | struct binder_alloc *alloc) |
963 | { |
964 | struct binder_buffer *buffer; |
965 | struct rb_node *n; |
966 | |
967 | spin_lock(lock: &alloc->lock); |
968 | for (n = rb_first(&alloc->allocated_buffers); n; n = rb_next(n)) { |
969 | buffer = rb_entry(n, struct binder_buffer, rb_node); |
970 | seq_printf(m, fmt: " buffer %d: %lx size %zd:%zd:%zd %s\n" , |
971 | buffer->debug_id, |
972 | buffer->user_data - alloc->buffer, |
973 | buffer->data_size, buffer->offsets_size, |
974 | buffer->extra_buffers_size, |
975 | buffer->transaction ? "active" : "delivered" ); |
976 | } |
977 | spin_unlock(lock: &alloc->lock); |
978 | } |
979 | |
980 | /** |
981 | * binder_alloc_print_pages() - print page usage |
982 | * @m: seq_file for output via seq_printf() |
983 | * @alloc: binder_alloc for this proc |
984 | */ |
985 | void binder_alloc_print_pages(struct seq_file *m, |
986 | struct binder_alloc *alloc) |
987 | { |
988 | struct binder_lru_page *page; |
989 | int i; |
990 | int active = 0; |
991 | int lru = 0; |
992 | int free = 0; |
993 | |
994 | spin_lock(lock: &alloc->lock); |
995 | /* |
996 | * Make sure the binder_alloc is fully initialized, otherwise we might |
997 | * read inconsistent state. |
998 | */ |
999 | if (binder_alloc_get_vma(alloc) != NULL) { |
1000 | for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) { |
1001 | page = &alloc->pages[i]; |
1002 | if (!page->page_ptr) |
1003 | free++; |
1004 | else if (list_empty(head: &page->lru)) |
1005 | active++; |
1006 | else |
1007 | lru++; |
1008 | } |
1009 | } |
1010 | spin_unlock(lock: &alloc->lock); |
1011 | seq_printf(m, fmt: " pages: %d:%d:%d\n" , active, lru, free); |
1012 | seq_printf(m, fmt: " pages high watermark: %zu\n" , alloc->pages_high); |
1013 | } |
1014 | |
1015 | /** |
1016 | * binder_alloc_get_allocated_count() - return count of buffers |
1017 | * @alloc: binder_alloc for this proc |
1018 | * |
1019 | * Return: count of allocated buffers |
1020 | */ |
1021 | int binder_alloc_get_allocated_count(struct binder_alloc *alloc) |
1022 | { |
1023 | struct rb_node *n; |
1024 | int count = 0; |
1025 | |
1026 | spin_lock(lock: &alloc->lock); |
1027 | for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n)) |
1028 | count++; |
1029 | spin_unlock(lock: &alloc->lock); |
1030 | return count; |
1031 | } |
1032 | |
1033 | |
1034 | /** |
1035 | * binder_alloc_vma_close() - invalidate address space |
1036 | * @alloc: binder_alloc for this proc |
1037 | * |
1038 | * Called from binder_vma_close() when releasing address space. |
1039 | * Clears alloc->vma to prevent new incoming transactions from |
1040 | * allocating more buffers. |
1041 | */ |
1042 | void binder_alloc_vma_close(struct binder_alloc *alloc) |
1043 | { |
1044 | binder_alloc_set_vma(alloc, NULL); |
1045 | } |
1046 | |
1047 | /** |
1048 | * binder_alloc_free_page() - shrinker callback to free pages |
1049 | * @item: item to free |
1050 | * @lock: lock protecting the item |
1051 | * @cb_arg: callback argument |
1052 | * |
1053 | * Called from list_lru_walk() in binder_shrink_scan() to free |
1054 | * up pages when the system is under memory pressure. |
1055 | */ |
1056 | enum lru_status binder_alloc_free_page(struct list_head *item, |
1057 | struct list_lru_one *lru, |
1058 | spinlock_t *lock, |
1059 | void *cb_arg) |
1060 | __must_hold(lock) |
1061 | { |
1062 | struct binder_lru_page *page = container_of(item, typeof(*page), lru); |
1063 | struct binder_alloc *alloc = page->alloc; |
1064 | struct mm_struct *mm = alloc->mm; |
1065 | struct vm_area_struct *vma; |
1066 | struct page *page_to_free; |
1067 | unsigned long page_addr; |
1068 | size_t index; |
1069 | |
1070 | if (!mmget_not_zero(mm)) |
1071 | goto err_mmget; |
1072 | if (!mmap_read_trylock(mm)) |
1073 | goto err_mmap_read_lock_failed; |
1074 | if (!spin_trylock(lock: &alloc->lock)) |
1075 | goto err_get_alloc_lock_failed; |
1076 | if (!page->page_ptr) |
1077 | goto err_page_already_freed; |
1078 | |
1079 | index = page - alloc->pages; |
1080 | page_addr = alloc->buffer + index * PAGE_SIZE; |
1081 | |
1082 | vma = vma_lookup(mm, addr: page_addr); |
1083 | if (vma && vma != binder_alloc_get_vma(alloc)) |
1084 | goto err_invalid_vma; |
1085 | |
1086 | trace_binder_unmap_kernel_start(alloc, page_index: index); |
1087 | |
1088 | page_to_free = page->page_ptr; |
1089 | page->page_ptr = NULL; |
1090 | |
1091 | trace_binder_unmap_kernel_end(alloc, page_index: index); |
1092 | |
1093 | list_lru_isolate(list: lru, item); |
1094 | spin_unlock(lock: &alloc->lock); |
1095 | spin_unlock(lock); |
1096 | |
1097 | if (vma) { |
1098 | trace_binder_unmap_user_start(alloc, page_index: index); |
1099 | |
1100 | zap_page_range_single(vma, address: page_addr, PAGE_SIZE, NULL); |
1101 | |
1102 | trace_binder_unmap_user_end(alloc, page_index: index); |
1103 | } |
1104 | |
1105 | mmap_read_unlock(mm); |
1106 | mmput_async(mm); |
1107 | __free_page(page_to_free); |
1108 | |
1109 | spin_lock(lock); |
1110 | return LRU_REMOVED_RETRY; |
1111 | |
1112 | err_invalid_vma: |
1113 | err_page_already_freed: |
1114 | spin_unlock(lock: &alloc->lock); |
1115 | err_get_alloc_lock_failed: |
1116 | mmap_read_unlock(mm); |
1117 | err_mmap_read_lock_failed: |
1118 | mmput_async(mm); |
1119 | err_mmget: |
1120 | return LRU_SKIP; |
1121 | } |
1122 | |
1123 | static unsigned long |
1124 | binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc) |
1125 | { |
1126 | return list_lru_count(lru: &binder_freelist); |
1127 | } |
1128 | |
1129 | static unsigned long |
1130 | binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) |
1131 | { |
1132 | return list_lru_walk(lru: &binder_freelist, isolate: binder_alloc_free_page, |
1133 | NULL, nr_to_walk: sc->nr_to_scan); |
1134 | } |
1135 | |
1136 | static struct shrinker *binder_shrinker; |
1137 | |
1138 | /** |
1139 | * binder_alloc_init() - called by binder_open() for per-proc initialization |
1140 | * @alloc: binder_alloc for this proc |
1141 | * |
1142 | * Called from binder_open() to initialize binder_alloc fields for |
1143 | * new binder proc |
1144 | */ |
1145 | void binder_alloc_init(struct binder_alloc *alloc) |
1146 | { |
1147 | alloc->pid = current->group_leader->pid; |
1148 | alloc->mm = current->mm; |
1149 | mmgrab(mm: alloc->mm); |
1150 | spin_lock_init(&alloc->lock); |
1151 | INIT_LIST_HEAD(list: &alloc->buffers); |
1152 | } |
1153 | |
1154 | int binder_alloc_shrinker_init(void) |
1155 | { |
1156 | int ret; |
1157 | |
1158 | ret = list_lru_init(&binder_freelist); |
1159 | if (ret) |
1160 | return ret; |
1161 | |
1162 | binder_shrinker = shrinker_alloc(flags: 0, fmt: "android-binder" ); |
1163 | if (!binder_shrinker) { |
1164 | list_lru_destroy(lru: &binder_freelist); |
1165 | return -ENOMEM; |
1166 | } |
1167 | |
1168 | binder_shrinker->count_objects = binder_shrink_count; |
1169 | binder_shrinker->scan_objects = binder_shrink_scan; |
1170 | |
1171 | shrinker_register(shrinker: binder_shrinker); |
1172 | |
1173 | return 0; |
1174 | } |
1175 | |
1176 | void binder_alloc_shrinker_exit(void) |
1177 | { |
1178 | shrinker_free(shrinker: binder_shrinker); |
1179 | list_lru_destroy(lru: &binder_freelist); |
1180 | } |
1181 | |
1182 | /** |
1183 | * check_buffer() - verify that buffer/offset is safe to access |
1184 | * @alloc: binder_alloc for this proc |
1185 | * @buffer: binder buffer to be accessed |
1186 | * @offset: offset into @buffer data |
1187 | * @bytes: bytes to access from offset |
1188 | * |
1189 | * Check that the @offset/@bytes are within the size of the given |
1190 | * @buffer and that the buffer is currently active and not freeable. |
1191 | * Offsets must also be multiples of sizeof(u32). The kernel is |
1192 | * allowed to touch the buffer in two cases: |
1193 | * |
1194 | * 1) when the buffer is being created: |
1195 | * (buffer->free == 0 && buffer->allow_user_free == 0) |
1196 | * 2) when the buffer is being torn down: |
1197 | * (buffer->free == 0 && buffer->transaction == NULL). |
1198 | * |
1199 | * Return: true if the buffer is safe to access |
1200 | */ |
1201 | static inline bool check_buffer(struct binder_alloc *alloc, |
1202 | struct binder_buffer *buffer, |
1203 | binder_size_t offset, size_t bytes) |
1204 | { |
1205 | size_t buffer_size = binder_alloc_buffer_size(alloc, buffer); |
1206 | |
1207 | return buffer_size >= bytes && |
1208 | offset <= buffer_size - bytes && |
1209 | IS_ALIGNED(offset, sizeof(u32)) && |
1210 | !buffer->free && |
1211 | (!buffer->allow_user_free || !buffer->transaction); |
1212 | } |
1213 | |
1214 | /** |
1215 | * binder_alloc_copy_user_to_buffer() - copy src user to tgt user |
1216 | * @alloc: binder_alloc for this proc |
1217 | * @buffer: binder buffer to be accessed |
1218 | * @buffer_offset: offset into @buffer data |
1219 | * @from: userspace pointer to source buffer |
1220 | * @bytes: bytes to copy |
1221 | * |
1222 | * Copy bytes from source userspace to target buffer. |
1223 | * |
1224 | * Return: bytes remaining to be copied |
1225 | */ |
1226 | unsigned long |
1227 | binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc, |
1228 | struct binder_buffer *buffer, |
1229 | binder_size_t buffer_offset, |
1230 | const void __user *from, |
1231 | size_t bytes) |
1232 | { |
1233 | if (!check_buffer(alloc, buffer, offset: buffer_offset, bytes)) |
1234 | return bytes; |
1235 | |
1236 | while (bytes) { |
1237 | unsigned long size; |
1238 | unsigned long ret; |
1239 | struct page *page; |
1240 | pgoff_t pgoff; |
1241 | void *kptr; |
1242 | |
1243 | page = binder_alloc_get_page(alloc, buffer, |
1244 | buffer_offset, pgoffp: &pgoff); |
1245 | size = min_t(size_t, bytes, PAGE_SIZE - pgoff); |
1246 | kptr = kmap_local_page(page) + pgoff; |
1247 | ret = copy_from_user(to: kptr, from, n: size); |
1248 | kunmap_local(kptr); |
1249 | if (ret) |
1250 | return bytes - size + ret; |
1251 | bytes -= size; |
1252 | from += size; |
1253 | buffer_offset += size; |
1254 | } |
1255 | return 0; |
1256 | } |
1257 | |
1258 | static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc, |
1259 | bool to_buffer, |
1260 | struct binder_buffer *buffer, |
1261 | binder_size_t buffer_offset, |
1262 | void *ptr, |
1263 | size_t bytes) |
1264 | { |
1265 | /* All copies must be 32-bit aligned and 32-bit size */ |
1266 | if (!check_buffer(alloc, buffer, offset: buffer_offset, bytes)) |
1267 | return -EINVAL; |
1268 | |
1269 | while (bytes) { |
1270 | unsigned long size; |
1271 | struct page *page; |
1272 | pgoff_t pgoff; |
1273 | |
1274 | page = binder_alloc_get_page(alloc, buffer, |
1275 | buffer_offset, pgoffp: &pgoff); |
1276 | size = min_t(size_t, bytes, PAGE_SIZE - pgoff); |
1277 | if (to_buffer) |
1278 | memcpy_to_page(page, offset: pgoff, from: ptr, len: size); |
1279 | else |
1280 | memcpy_from_page(to: ptr, page, offset: pgoff, len: size); |
1281 | bytes -= size; |
1282 | pgoff = 0; |
1283 | ptr = ptr + size; |
1284 | buffer_offset += size; |
1285 | } |
1286 | return 0; |
1287 | } |
1288 | |
1289 | int binder_alloc_copy_to_buffer(struct binder_alloc *alloc, |
1290 | struct binder_buffer *buffer, |
1291 | binder_size_t buffer_offset, |
1292 | void *src, |
1293 | size_t bytes) |
1294 | { |
1295 | return binder_alloc_do_buffer_copy(alloc, to_buffer: true, buffer, buffer_offset, |
1296 | ptr: src, bytes); |
1297 | } |
1298 | |
1299 | int binder_alloc_copy_from_buffer(struct binder_alloc *alloc, |
1300 | void *dest, |
1301 | struct binder_buffer *buffer, |
1302 | binder_size_t buffer_offset, |
1303 | size_t bytes) |
1304 | { |
1305 | return binder_alloc_do_buffer_copy(alloc, to_buffer: false, buffer, buffer_offset, |
1306 | ptr: dest, bytes); |
1307 | } |
1308 | |