drivers/android/binder_alloc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* binder_alloc.c
   3  *
   4  * Android IPC Subsystem
   5  *
   6  * Copyright (C) 2007-2017 Google, Inc.
   7  */
   8
   9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11 #include <linux/list.h>
  12 #include <linux/sched/mm.h>
  13 #include <linux/module.h>
  14 #include <linux/rtmutex.h>
  15 #include <linux/rbtree.h>
  16 #include <linux/seq_file.h>
  17 #include <linux/vmalloc.h>
  18 #include <linux/slab.h>
  19 #include <linux/sched.h>
  20 #include <linux/list_lru.h>
  21 #include <linux/ratelimit.h>
  22 #include <asm/cacheflush.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/highmem.h>
  25 #include <linux/sizes.h>
  26 #include "binder_alloc.h"
  27 #include "binder_trace.h"
  28
  29 struct list_lru binder_alloc_lru;
  30
  31 static DEFINE_MUTEX(binder_alloc_mmap_lock);
  32
  33 enum {
  34         BINDER_DEBUG_USER_ERROR             = 1U << 0,
  35         BINDER_DEBUG_OPEN_CLOSE             = 1U << 1,
  36         BINDER_DEBUG_BUFFER_ALLOC           = 1U << 2,
  37         BINDER_DEBUG_BUFFER_ALLOC_ASYNC     = 1U << 3,
  38 };
  39 static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
  40
  41 module_param_named(debug_mask, binder_alloc_debug_mask,
  42                    uint, 0644);
  43
  44 #define binder_alloc_debug(mask, x...) \
  45         do { \
  46                 if (binder_alloc_debug_mask & mask) \
  47                         pr_info_ratelimited(x); \
  48         } while (0)
  49
  50 static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
  51 {
  52         return list_entry(buffer->entry.next, struct binder_buffer, entry);
  53 }
  54
  55 static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
  56 {
  57         return list_entry(buffer->entry.prev, struct binder_buffer, entry);
  58 }
  59
  60 static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
  61                                        struct binder_buffer *buffer)
  62 {
  63         if (list_is_last(&buffer->entry, &alloc->buffers))
  64                 return alloc->buffer + alloc->buffer_size - buffer->user_data;
  65         return binder_buffer_next(buffer)->user_data - buffer->user_data;
  66 }
  67
  68 static void binder_insert_free_buffer(struct binder_alloc *alloc,
  69                                       struct binder_buffer *new_buffer)
  70 {
  71         struct rb_node **p = &alloc->free_buffers.rb_node;
  72         struct rb_node *parent = NULL;
  73         struct binder_buffer *buffer;
  74         size_t buffer_size;
  75         size_t new_buffer_size;
  76
  77         BUG_ON(!new_buffer->free);
  78
  79         new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
  80
  81         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
  82                      "%d: add free buffer, size %zd, at %pK\n",
  83                       alloc->pid, new_buffer_size, new_buffer);
  84
  85         while (*p) {
  86                 parent = *p;
  87                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
  88                 BUG_ON(!buffer->free);
  89
  90                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
  91
  92                 if (new_buffer_size < buffer_size)
  93                         p = &parent->rb_left;
  94                 else
  95                         p = &parent->rb_right;
  96         }
  97         rb_link_node(&new_buffer->rb_node, parent, p);
  98         rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
  99 }
 100
 101 static void binder_insert_allocated_buffer_locked(
 102                 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
 103 {
 104         struct rb_node **p = &alloc->allocated_buffers.rb_node;
 105         struct rb_node *parent = NULL;
 106         struct binder_buffer *buffer;
 107
 108         BUG_ON(new_buffer->free);
 109
 110         while (*p) {
 111                 parent = *p;
 112                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
 113                 BUG_ON(buffer->free);
 114
 115                 if (new_buffer->user_data < buffer->user_data)
 116                         p = &parent->rb_left;
 117                 else if (new_buffer->user_data > buffer->user_data)
 118                         p = &parent->rb_right;
 119                 else
 120                         BUG();
 121         }
 122         rb_link_node(&new_buffer->rb_node, parent, p);
 123         rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
 124 }
 125
 126 static struct binder_buffer *binder_alloc_prepare_to_free_locked(
 127                 struct binder_alloc *alloc,
 128                 uintptr_t user_ptr)
 129 {
 130         struct rb_node *n = alloc->allocated_buffers.rb_node;
 131         struct binder_buffer *buffer;
 132         void __user *uptr;
 133
 134         uptr = (void __user *)user_ptr;
 135
 136         while (n) {
 137                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 138                 BUG_ON(buffer->free);
 139
 140                 if (uptr < buffer->user_data)
 141                         n = n->rb_left;
 142                 else if (uptr > buffer->user_data)
 143                         n = n->rb_right;
 144                 else {
 145                         /*
 146                          * Guard against user threads attempting to
 147                          * free the buffer when in use by kernel or
 148                          * after it's already been freed.
 149                          */
 150                         if (!buffer->allow_user_free)
 151                                 return ERR_PTR(-EPERM);
 152                         buffer->allow_user_free = 0;
 153                         return buffer;
 154                 }
 155         }
 156         return NULL;
 157 }
 158
 159 /**
 160  * binder_alloc_prepare_to_free() - get buffer given user ptr
 161  * @alloc:      binder_alloc for this proc
 162  * @user_ptr:   User pointer to buffer data
 163  *
 164  * Validate userspace pointer to buffer data and return buffer corresponding to
 165  * that user pointer. Search the rb tree for buffer that matches user data
 166  * pointer.
 167  *
 168  * Return:      Pointer to buffer or NULL
 169  */
 170 struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
 171                                                    uintptr_t user_ptr)
 172 {
 173         struct binder_buffer *buffer;
 174
 175         mutex_lock(&alloc->mutex);
 176         buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
 177         mutex_unlock(&alloc->mutex);
 178         return buffer;
 179 }
 180
 181 static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
 182                                     void __user *start, void __user *end)
 183 {
 184         void __user *page_addr;
 185         unsigned long user_page_addr;
 186         struct binder_lru_page *page;
 187         struct vm_area_struct *vma = NULL;
 188         struct mm_struct *mm = NULL;
 189         bool need_mm = false;
 190
 191         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 192                      "%d: %s pages %pK-%pK\n", alloc->pid,
 193                      allocate ? "allocate" : "free", start, end);
 194
 195         if (end <= start)
 196                 return 0;
 197
 198         trace_binder_update_page_range(alloc, allocate, start, end);
 199
 200         if (allocate == 0)
 201                 goto free_range;
 202
 203         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 204                 page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
 205                 if (!page->page_ptr) {
 206                         need_mm = true;
 207                         break;
 208                 }
 209         }
 210
 211         if (need_mm && mmget_not_zero(alloc->vma_vm_mm))
 212                 mm = alloc->vma_vm_mm;
 213
 214         if (mm) {
 215                 mmap_read_lock(mm);
 216                 vma = vma_lookup(mm, alloc->vma_addr);
 217         }
 218
 219         if (!vma && need_mm) {
 220                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 221                                    "%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
 222                                    alloc->pid);
 223                 goto err_no_vma;
 224         }
 225
 226         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 227                 int ret;
 228                 bool on_lru;
 229                 size_t index;
 230
 231                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 232                 page = &alloc->pages[index];
 233
 234                 if (page->page_ptr) {
 235                         trace_binder_alloc_lru_start(alloc, index);
 236
 237                         on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
 238                         WARN_ON(!on_lru);
 239
 240                         trace_binder_alloc_lru_end(alloc, index);
 241                         continue;
 242                 }
 243
 244                 if (WARN_ON(!vma))
 245                         goto err_page_ptr_cleared;
 246
 247                 trace_binder_alloc_page_start(alloc, index);
 248                 page->page_ptr = alloc_page(GFP_KERNEL |
 249                                             __GFP_HIGHMEM |
 250                                             __GFP_ZERO);
 251                 if (!page->page_ptr) {
 252                         pr_err("%d: binder_alloc_buf failed for page at %pK\n",
 253                                 alloc->pid, page_addr);
 254                         goto err_alloc_page_failed;
 255                 }
 256                 page->alloc = alloc;
 257                 INIT_LIST_HEAD(&page->lru);
 258
 259                 user_page_addr = (uintptr_t)page_addr;
 260                 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
 261                 if (ret) {
 262                         pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
 263                                alloc->pid, user_page_addr);
 264                         goto err_vm_insert_page_failed;
 265                 }
 266
 267                 if (index + 1 > alloc->pages_high)
 268                         alloc->pages_high = index + 1;
 269
 270                 trace_binder_alloc_page_end(alloc, index);
 271         }
 272         if (mm) {
 273                 mmap_read_unlock(mm);
 274                 mmput(mm);
 275         }
 276         return 0;
 277
 278 free_range:
 279         for (page_addr = end - PAGE_SIZE; 1; page_addr -= PAGE_SIZE) {
 280                 bool ret;
 281                 size_t index;
 282
 283                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 284                 page = &alloc->pages[index];
 285
 286                 trace_binder_free_lru_start(alloc, index);
 287
 288                 ret = list_lru_add(&binder_alloc_lru, &page->lru);
 289                 WARN_ON(!ret);
 290
 291                 trace_binder_free_lru_end(alloc, index);
 292                 if (page_addr == start)
 293                         break;
 294                 continue;
 295
 296 err_vm_insert_page_failed:
 297                 __free_page(page->page_ptr);
 298                 page->page_ptr = NULL;
 299 err_alloc_page_failed:
 300 err_page_ptr_cleared:
 301                 if (page_addr == start)
 302                         break;
 303         }
 304 err_no_vma:
 305         if (mm) {
 306                 mmap_read_unlock(mm);
 307                 mmput(mm);
 308         }
 309         return vma ? -ENOMEM : -ESRCH;
 310 }
 311
 312
 313 static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
 314                 struct vm_area_struct *vma)
 315 {
 316         unsigned long vm_start = 0;
 317
 318         /*
 319          * Allow clearing the vma with holding just the read lock to allow
 320          * munmapping downgrade of the write lock before freeing and closing the
 321          * file using binder_alloc_vma_close().
 322          */
 323         if (vma) {
 324                 vm_start = vma->vm_start;
 325                 mmap_assert_write_locked(alloc->vma_vm_mm);
 326         } else {
 327                 mmap_assert_locked(alloc->vma_vm_mm);
 328         }
 329
 330         alloc->vma_addr = vm_start;
 331 }
 332
 333 static inline struct vm_area_struct *binder_alloc_get_vma(
 334                 struct binder_alloc *alloc)
 335 {
 336         struct vm_area_struct *vma = NULL;
 337
 338         if (alloc->vma_addr)
 339                 vma = vma_lookup(alloc->vma_vm_mm, alloc->vma_addr);
 340
 341         return vma;
 342 }
 343
 344 static bool debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
 345 {
 346         /*
 347          * Find the amount and size of buffers allocated by the current caller;
 348          * The idea is that once we cross the threshold, whoever is responsible
 349          * for the low async space is likely to try to send another async txn,
 350          * and at some point we'll catch them in the act. This is more efficient
 351          * than keeping a map per pid.
 352          */
 353         struct rb_node *n;
 354         struct binder_buffer *buffer;
 355         size_t total_alloc_size = 0;
 356         size_t num_buffers = 0;
 357
 358         for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 359                  n = rb_next(n)) {
 360                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 361                 if (buffer->pid != pid)
 362                         continue;
 363                 if (!buffer->async_transaction)
 364                         continue;
 365                 total_alloc_size += binder_alloc_buffer_size(alloc, buffer)
 366                         + sizeof(struct binder_buffer);
 367                 num_buffers++;
 368         }
 369
 370         /*
 371          * Warn if this pid has more than 50 transactions, or more than 50% of
 372          * async space (which is 25% of total buffer size). Oneway spam is only
 373          * detected when the threshold is exceeded.
 374          */
 375         if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) {
 376                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 377                              "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n",
 378                               alloc->pid, pid, num_buffers, total_alloc_size);
 379                 if (!alloc->oneway_spam_detected) {
 380                         alloc->oneway_spam_detected = true;
 381                         return true;
 382                 }
 383         }
 384         return false;
 385 }
 386
 387 static struct binder_buffer *binder_alloc_new_buf_locked(
 388                                 struct binder_alloc *alloc,
 389                                 size_t data_size,
 390                                 size_t offsets_size,
 391                                 size_t extra_buffers_size,
 392                                 int is_async,
 393                                 int pid)
 394 {
 395         struct rb_node *n = alloc->free_buffers.rb_node;
 396         struct binder_buffer *buffer;
 397         size_t buffer_size;
 398         struct rb_node *best_fit = NULL;
 399         void __user *has_page_addr;
 400         void __user *end_page_addr;
 401         size_t size, data_offsets_size;
 402         int ret;
 403
 404         if (!binder_alloc_get_vma(alloc)) {
 405                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 406                                    "%d: binder_alloc_buf, no vma\n",
 407                                    alloc->pid);
 408                 return ERR_PTR(-ESRCH);
 409         }
 410
 411         data_offsets_size = ALIGN(data_size, sizeof(void *)) +
 412                 ALIGN(offsets_size, sizeof(void *));
 413
 414         if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
 415                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 416                                 "%d: got transaction with invalid size %zd-%zd\n",
 417                                 alloc->pid, data_size, offsets_size);
 418                 return ERR_PTR(-EINVAL);
 419         }
 420         size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
 421         if (size < data_offsets_size || size < extra_buffers_size) {
 422                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 423                                 "%d: got transaction with invalid extra_buffers_size %zd\n",
 424                                 alloc->pid, extra_buffers_size);
 425                 return ERR_PTR(-EINVAL);
 426         }
 427         if (is_async &&
 428             alloc->free_async_space < size + sizeof(struct binder_buffer)) {
 429                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 430                              "%d: binder_alloc_buf size %zd failed, no async space left\n",
 431                               alloc->pid, size);
 432                 return ERR_PTR(-ENOSPC);
 433         }
 434
 435         /* Pad 0-size buffers so they get assigned unique addresses */
 436         size = max(size, sizeof(void *));
 437
 438         while (n) {
 439                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 440                 BUG_ON(!buffer->free);
 441                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 442
 443                 if (size < buffer_size) {
 444                         best_fit = n;
 445                         n = n->rb_left;
 446                 } else if (size > buffer_size)
 447                         n = n->rb_right;
 448                 else {
 449                         best_fit = n;
 450                         break;
 451                 }
 452         }
 453         if (best_fit == NULL) {
 454                 size_t allocated_buffers = 0;
 455                 size_t largest_alloc_size = 0;
 456                 size_t total_alloc_size = 0;
 457                 size_t free_buffers = 0;
 458                 size_t largest_free_size = 0;
 459                 size_t total_free_size = 0;
 460
 461                 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 462                      n = rb_next(n)) {
 463                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 464                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 465                         allocated_buffers++;
 466                         total_alloc_size += buffer_size;
 467                         if (buffer_size > largest_alloc_size)
 468                                 largest_alloc_size = buffer_size;
 469                 }
 470                 for (n = rb_first(&alloc->free_buffers); n != NULL;
 471                      n = rb_next(n)) {
 472                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 473                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 474                         free_buffers++;
 475                         total_free_size += buffer_size;
 476                         if (buffer_size > largest_free_size)
 477                                 largest_free_size = buffer_size;
 478                 }
 479                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 480                                    "%d: binder_alloc_buf size %zd failed, no address space\n",
 481                                    alloc->pid, size);
 482                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 483                                    "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
 484                                    total_alloc_size, allocated_buffers,
 485                                    largest_alloc_size, total_free_size,
 486                                    free_buffers, largest_free_size);
 487                 return ERR_PTR(-ENOSPC);
 488         }
 489         if (n == NULL) {
 490                 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
 491                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 492         }
 493
 494         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 495                      "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
 496                       alloc->pid, size, buffer, buffer_size);
 497
 498         has_page_addr = (void __user *)
 499                 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
 500         WARN_ON(n && buffer_size != size);
 501         end_page_addr =
 502                 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
 503         if (end_page_addr > has_page_addr)
 504                 end_page_addr = has_page_addr;
 505         ret = binder_update_page_range(alloc, 1, (void __user *)
 506                 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
 507         if (ret)
 508                 return ERR_PTR(ret);
 509
 510         if (buffer_size != size) {
 511                 struct binder_buffer *new_buffer;
 512
 513                 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 514                 if (!new_buffer) {
 515                         pr_err("%s: %d failed to alloc new buffer struct\n",
 516                                __func__, alloc->pid);
 517                         goto err_alloc_buf_struct_failed;
 518                 }
 519                 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
 520                 list_add(&new_buffer->entry, &buffer->entry);
 521                 new_buffer->free = 1;
 522                 binder_insert_free_buffer(alloc, new_buffer);
 523         }
 524
 525         rb_erase(best_fit, &alloc->free_buffers);
 526         buffer->free = 0;
 527         buffer->allow_user_free = 0;
 528         binder_insert_allocated_buffer_locked(alloc, buffer);
 529         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 530                      "%d: binder_alloc_buf size %zd got %pK\n",
 531                       alloc->pid, size, buffer);
 532         buffer->data_size = data_size;
 533         buffer->offsets_size = offsets_size;
 534         buffer->async_transaction = is_async;
 535         buffer->extra_buffers_size = extra_buffers_size;
 536         buffer->pid = pid;
 537         buffer->oneway_spam_suspect = false;
 538         if (is_async) {
 539                 alloc->free_async_space -= size + sizeof(struct binder_buffer);
 540                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 541                              "%d: binder_alloc_buf size %zd async free %zd\n",
 542                               alloc->pid, size, alloc->free_async_space);
 543                 if (alloc->free_async_space < alloc->buffer_size / 10) {
 544                         /*
 545                          * Start detecting spammers once we have less than 20%
 546                          * of async space left (which is less than 10% of total
 547                          * buffer size).
 548                          */
 549                         buffer->oneway_spam_suspect = debug_low_async_space_locked(alloc, pid);
 550                 } else {
 551                         alloc->oneway_spam_detected = false;
 552                 }
 553         }
 554         return buffer;
 555
 556 err_alloc_buf_struct_failed:
 557         binder_update_page_range(alloc, 0, (void __user *)
 558                                  PAGE_ALIGN((uintptr_t)buffer->user_data),
 559                                  end_page_addr);
 560         return ERR_PTR(-ENOMEM);
 561 }
 562
 563 /**
 564  * binder_alloc_new_buf() - Allocate a new binder buffer
 565  * @alloc:              binder_alloc for this proc
 566  * @data_size:          size of user data buffer
 567  * @offsets_size:       user specified buffer offset
 568  * @extra_buffers_size: size of extra space for meta-data (eg, security context)
 569  * @is_async:           buffer for async transaction
 570  * @pid:                                pid to attribute allocation to (used for debugging)
 571  *
 572  * Allocate a new buffer given the requested sizes. Returns
 573  * the kernel version of the buffer pointer. The size allocated
 574  * is the sum of the three given sizes (each rounded up to
 575  * pointer-sized boundary)
 576  *
 577  * Return:      The allocated buffer or %NULL if error
 578  */
 579 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 580                                            size_t data_size,
 581                                            size_t offsets_size,
 582                                            size_t extra_buffers_size,
 583                                            int is_async,
 584                                            int pid)
 585 {
 586         struct binder_buffer *buffer;
 587
 588         mutex_lock(&alloc->mutex);
 589         buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
 590                                              extra_buffers_size, is_async, pid);
 591         mutex_unlock(&alloc->mutex);
 592         return buffer;
 593 }
 594
 595 static void __user *buffer_start_page(struct binder_buffer *buffer)
 596 {
 597         return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
 598 }
 599
 600 static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
 601 {
 602         return (void __user *)
 603                 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
 604 }
 605
 606 static void binder_delete_free_buffer(struct binder_alloc *alloc,
 607                                       struct binder_buffer *buffer)
 608 {
 609         struct binder_buffer *prev, *next = NULL;
 610         bool to_free = true;
 611
 612         BUG_ON(alloc->buffers.next == &buffer->entry);
 613         prev = binder_buffer_prev(buffer);
 614         BUG_ON(!prev->free);
 615         if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
 616                 to_free = false;
 617                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 618                                    "%d: merge free, buffer %pK share page with %pK\n",
 619                                    alloc->pid, buffer->user_data,
 620                                    prev->user_data);
 621         }
 622
 623         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 624                 next = binder_buffer_next(buffer);
 625                 if (buffer_start_page(next) == buffer_start_page(buffer)) {
 626                         to_free = false;
 627                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 628                                            "%d: merge free, buffer %pK share page with %pK\n",
 629                                            alloc->pid,
 630                                            buffer->user_data,
 631                                            next->user_data);
 632                 }
 633         }
 634
 635         if (PAGE_ALIGNED(buffer->user_data)) {
 636                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 637                                    "%d: merge free, buffer start %pK is page aligned\n",
 638                                    alloc->pid, buffer->user_data);
 639                 to_free = false;
 640         }
 641
 642         if (to_free) {
 643                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 644                                    "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
 645                                    alloc->pid, buffer->user_data,
 646                                    prev->user_data,
 647                                    next ? next->user_data : NULL);
 648                 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
 649                                          buffer_start_page(buffer) + PAGE_SIZE);
 650         }
 651         list_del(&buffer->entry);
 652         kfree(buffer);
 653 }
 654
 655 static void binder_free_buf_locked(struct binder_alloc *alloc,
 656                                    struct binder_buffer *buffer)
 657 {
 658         size_t size, buffer_size;
 659
 660         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 661
 662         size = ALIGN(buffer->data_size, sizeof(void *)) +
 663                 ALIGN(buffer->offsets_size, sizeof(void *)) +
 664                 ALIGN(buffer->extra_buffers_size, sizeof(void *));
 665
 666         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 667                      "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
 668                       alloc->pid, buffer, size, buffer_size);
 669
 670         BUG_ON(buffer->free);
 671         BUG_ON(size > buffer_size);
 672         BUG_ON(buffer->transaction != NULL);
 673         BUG_ON(buffer->user_data < alloc->buffer);
 674         BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
 675
 676         if (buffer->async_transaction) {
 677                 alloc->free_async_space += buffer_size + sizeof(struct binder_buffer);
 678
 679                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 680                              "%d: binder_free_buf size %zd async free %zd\n",
 681                               alloc->pid, size, alloc->free_async_space);
 682         }
 683
 684         binder_update_page_range(alloc, 0,
 685                 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
 686                 (void __user *)(((uintptr_t)
 687                           buffer->user_data + buffer_size) & PAGE_MASK));
 688
 689         rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
 690         buffer->free = 1;
 691         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 692                 struct binder_buffer *next = binder_buffer_next(buffer);
 693
 694                 if (next->free) {
 695                         rb_erase(&next->rb_node, &alloc->free_buffers);
 696                         binder_delete_free_buffer(alloc, next);
 697                 }
 698         }
 699         if (alloc->buffers.next != &buffer->entry) {
 700                 struct binder_buffer *prev = binder_buffer_prev(buffer);
 701
 702                 if (prev->free) {
 703                         binder_delete_free_buffer(alloc, buffer);
 704                         rb_erase(&prev->rb_node, &alloc->free_buffers);
 705                         buffer = prev;
 706                 }
 707         }
 708         binder_insert_free_buffer(alloc, buffer);
 709 }
 710
 711 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
 712                                    struct binder_buffer *buffer);
 713 /**
 714  * binder_alloc_free_buf() - free a binder buffer
 715  * @alloc:      binder_alloc for this proc
 716  * @buffer:     kernel pointer to buffer
 717  *
 718  * Free the buffer allocated via binder_alloc_new_buf()
 719  */
 720 void binder_alloc_free_buf(struct binder_alloc *alloc,
 721                             struct binder_buffer *buffer)
 722 {
 723         /*
 724          * We could eliminate the call to binder_alloc_clear_buf()
 725          * from binder_alloc_deferred_release() by moving this to
 726          * binder_alloc_free_buf_locked(). However, that could
 727          * increase contention for the alloc mutex if clear_on_free
 728          * is used frequently for large buffers. The mutex is not
 729          * needed for correctness here.
 730          */
 731         if (buffer->clear_on_free) {
 732                 binder_alloc_clear_buf(alloc, buffer);
 733                 buffer->clear_on_free = false;
 734         }
 735         mutex_lock(&alloc->mutex);
 736         binder_free_buf_locked(alloc, buffer);
 737         mutex_unlock(&alloc->mutex);
 738 }
 739
 740 /**
 741  * binder_alloc_mmap_handler() - map virtual address space for proc
 742  * @alloc:      alloc structure for this proc
 743  * @vma:        vma passed to mmap()
 744  *
 745  * Called by binder_mmap() to initialize the space specified in
 746  * vma for allocating binder buffers
 747  *
 748  * Return:
 749  *      0 = success
 750  *      -EBUSY = address space already mapped
 751  *      -ENOMEM = failed to map memory to given address space
 752  */
 753 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 754                               struct vm_area_struct *vma)
 755 {
 756         int ret;
 757         const char *failure_string;
 758         struct binder_buffer *buffer;
 759
 760         mutex_lock(&binder_alloc_mmap_lock);
 761         if (alloc->buffer_size) {
 762                 ret = -EBUSY;
 763                 failure_string = "already mapped";
 764                 goto err_already_mapped;
 765         }
 766         alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
 767                                    SZ_4M);
 768         mutex_unlock(&binder_alloc_mmap_lock);
 769
 770         alloc->buffer = (void __user *)vma->vm_start;
 771
 772         alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
 773                                sizeof(alloc->pages[0]),
 774                                GFP_KERNEL);
 775         if (alloc->pages == NULL) {
 776                 ret = -ENOMEM;
 777                 failure_string = "alloc page array";
 778                 goto err_alloc_pages_failed;
 779         }
 780
 781         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 782         if (!buffer) {
 783                 ret = -ENOMEM;
 784                 failure_string = "alloc buffer struct";
 785                 goto err_alloc_buf_struct_failed;
 786         }
 787
 788         buffer->user_data = alloc->buffer;
 789         list_add(&buffer->entry, &alloc->buffers);
 790         buffer->free = 1;
 791         binder_insert_free_buffer(alloc, buffer);
 792         alloc->free_async_space = alloc->buffer_size / 2;
 793         binder_alloc_set_vma(alloc, vma);
 794
 795         return 0;
 796
 797 err_alloc_buf_struct_failed:
 798         kfree(alloc->pages);
 799         alloc->pages = NULL;
 800 err_alloc_pages_failed:
 801         alloc->buffer = NULL;
 802         mutex_lock(&binder_alloc_mmap_lock);
 803         alloc->buffer_size = 0;
 804 err_already_mapped:
 805         mutex_unlock(&binder_alloc_mmap_lock);
 806         binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 807                            "%s: %d %lx-%lx %s failed %d\n", __func__,
 808                            alloc->pid, vma->vm_start, vma->vm_end,
 809                            failure_string, ret);
 810         return ret;
 811 }
 812
 813
 814 void binder_alloc_deferred_release(struct binder_alloc *alloc)
 815 {
 816         struct rb_node *n;
 817         int buffers, page_count;
 818         struct binder_buffer *buffer;
 819
 820         buffers = 0;
 821         mutex_lock(&alloc->mutex);
 822         BUG_ON(alloc->vma_addr &&
 823                vma_lookup(alloc->vma_vm_mm, alloc->vma_addr));
 824
 825         while ((n = rb_first(&alloc->allocated_buffers))) {
 826                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 827
 828                 /* Transaction should already have been freed */
 829                 BUG_ON(buffer->transaction);
 830
 831                 if (buffer->clear_on_free) {
 832                         binder_alloc_clear_buf(alloc, buffer);
 833                         buffer->clear_on_free = false;
 834                 }
 835                 binder_free_buf_locked(alloc, buffer);
 836                 buffers++;
 837         }
 838
 839         while (!list_empty(&alloc->buffers)) {
 840                 buffer = list_first_entry(&alloc->buffers,
 841                                           struct binder_buffer, entry);
 842                 WARN_ON(!buffer->free);
 843
 844                 list_del(&buffer->entry);
 845                 WARN_ON_ONCE(!list_empty(&alloc->buffers));
 846                 kfree(buffer);
 847         }
 848
 849         page_count = 0;
 850         if (alloc->pages) {
 851                 int i;
 852
 853                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 854                         void __user *page_addr;
 855                         bool on_lru;
 856
 857                         if (!alloc->pages[i].page_ptr)
 858                                 continue;
 859
 860                         on_lru = list_lru_del(&binder_alloc_lru,
 861                                               &alloc->pages[i].lru);
 862                         page_addr = alloc->buffer + i * PAGE_SIZE;
 863                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 864                                      "%s: %d: page %d at %pK %s\n",
 865                                      __func__, alloc->pid, i, page_addr,
 866                                      on_lru ? "on lru" : "active");
 867                         __free_page(alloc->pages[i].page_ptr);
 868                         page_count++;
 869                 }
 870                 kfree(alloc->pages);
 871         }
 872         mutex_unlock(&alloc->mutex);
 873         if (alloc->vma_vm_mm)
 874                 mmdrop(alloc->vma_vm_mm);
 875
 876         binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
 877                      "%s: %d buffers %d, pages %d\n",
 878                      __func__, alloc->pid, buffers, page_count);
 879 }
 880
 881 static void print_binder_buffer(struct seq_file *m, const char *prefix,
 882                                 struct binder_buffer *buffer)
 883 {
 884         seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
 885                    prefix, buffer->debug_id, buffer->user_data,
 886                    buffer->data_size, buffer->offsets_size,
 887                    buffer->extra_buffers_size,
 888                    buffer->transaction ? "active" : "delivered");
 889 }
 890
 891 /**
 892  * binder_alloc_print_allocated() - print buffer info
 893  * @m:     seq_file for output via seq_printf()
 894  * @alloc: binder_alloc for this proc
 895  *
 896  * Prints information about every buffer associated with
 897  * the binder_alloc state to the given seq_file
 898  */
 899 void binder_alloc_print_allocated(struct seq_file *m,
 900                                   struct binder_alloc *alloc)
 901 {
 902         struct rb_node *n;
 903
 904         mutex_lock(&alloc->mutex);
 905         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 906                 print_binder_buffer(m, "  buffer",
 907                                     rb_entry(n, struct binder_buffer, rb_node));
 908         mutex_unlock(&alloc->mutex);
 909 }
 910
 911 /**
 912  * binder_alloc_print_pages() - print page usage
 913  * @m:     seq_file for output via seq_printf()
 914  * @alloc: binder_alloc for this proc
 915  */
 916 void binder_alloc_print_pages(struct seq_file *m,
 917                               struct binder_alloc *alloc)
 918 {
 919         struct binder_lru_page *page;
 920         int i;
 921         int active = 0;
 922         int lru = 0;
 923         int free = 0;
 924
 925         mutex_lock(&alloc->mutex);
 926         /*
 927          * Make sure the binder_alloc is fully initialized, otherwise we might
 928          * read inconsistent state.
 929          */
 930         if (binder_alloc_get_vma(alloc) != NULL) {
 931                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 932                         page = &alloc->pages[i];
 933                         if (!page->page_ptr)
 934                                 free++;
 935                         else if (list_empty(&page->lru))
 936                                 active++;
 937                         else
 938                                 lru++;
 939                 }
 940         }
 941         mutex_unlock(&alloc->mutex);
 942         seq_printf(m, "  pages: %d:%d:%d\n", active, lru, free);
 943         seq_printf(m, "  pages high watermark: %zu\n", alloc->pages_high);
 944 }
 945
 946 /**
 947  * binder_alloc_get_allocated_count() - return count of buffers
 948  * @alloc: binder_alloc for this proc
 949  *
 950  * Return: count of allocated buffers
 951  */
 952 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
 953 {
 954         struct rb_node *n;
 955         int count = 0;
 956
 957         mutex_lock(&alloc->mutex);
 958         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 959                 count++;
 960         mutex_unlock(&alloc->mutex);
 961         return count;
 962 }
 963
 964
 965 /**
 966  * binder_alloc_vma_close() - invalidate address space
 967  * @alloc: binder_alloc for this proc
 968  *
 969  * Called from binder_vma_close() when releasing address space.
 970  * Clears alloc->vma to prevent new incoming transactions from
 971  * allocating more buffers.
 972  */
 973 void binder_alloc_vma_close(struct binder_alloc *alloc)
 974 {
 975         binder_alloc_set_vma(alloc, NULL);
 976 }
 977
 978 /**
 979  * binder_alloc_free_page() - shrinker callback to free pages
 980  * @item:   item to free
 981  * @lock:   lock protecting the item
 982  * @cb_arg: callback argument
 983  *
 984  * Called from list_lru_walk() in binder_shrink_scan() to free
 985  * up pages when the system is under memory pressure.
 986  */
 987 enum lru_status binder_alloc_free_page(struct list_head *item,
 988                                        struct list_lru_one *lru,
 989                                        spinlock_t *lock,
 990                                        void *cb_arg)
 991         __must_hold(lock)
 992 {
 993         struct mm_struct *mm = NULL;
 994         struct binder_lru_page *page = container_of(item,
 995                                                     struct binder_lru_page,
 996                                                     lru);
 997         struct binder_alloc *alloc;
 998         uintptr_t page_addr;
 999         size_t index;
1000         struct vm_area_struct *vma;
1001
1002         alloc = page->alloc;
1003         if (!mutex_trylock(&alloc->mutex))
1004                 goto err_get_alloc_mutex_failed;
1005
1006         if (!page->page_ptr)
1007                 goto err_page_already_freed;
1008
1009         index = page - alloc->pages;
1010         page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
1011
1012         mm = alloc->vma_vm_mm;
1013         if (!mmget_not_zero(mm))
1014                 goto err_mmget;
1015         if (!mmap_read_trylock(mm))
1016                 goto err_mmap_read_lock_failed;
1017         vma = binder_alloc_get_vma(alloc);
1018
1019         list_lru_isolate(lru, item);
1020         spin_unlock(lock);
1021
1022         if (vma) {
1023                 trace_binder_unmap_user_start(alloc, index);
1024
1025                 zap_page_range(vma, page_addr, PAGE_SIZE);
1026
1027                 trace_binder_unmap_user_end(alloc, index);
1028         }
1029         mmap_read_unlock(mm);
1030         mmput_async(mm);
1031
1032         trace_binder_unmap_kernel_start(alloc, index);
1033
1034         __free_page(page->page_ptr);
1035         page->page_ptr = NULL;
1036
1037         trace_binder_unmap_kernel_end(alloc, index);
1038
1039         spin_lock(lock);
1040         mutex_unlock(&alloc->mutex);
1041         return LRU_REMOVED_RETRY;
1042
1043 err_mmap_read_lock_failed:
1044         mmput_async(mm);
1045 err_mmget:
1046 err_page_already_freed:
1047         mutex_unlock(&alloc->mutex);
1048 err_get_alloc_mutex_failed:
1049         return LRU_SKIP;
1050 }
1051
1052 static unsigned long
1053 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
1054 {
1055         return list_lru_count(&binder_alloc_lru);
1056 }
1057
1058 static unsigned long
1059 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1060 {
1061         return list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
1062                             NULL, sc->nr_to_scan);
1063 }
1064
1065 static struct shrinker binder_shrinker = {
1066         .count_objects = binder_shrink_count,
1067         .scan_objects = binder_shrink_scan,
1068         .seeks = DEFAULT_SEEKS,
1069 };
1070
1071 /**
1072  * binder_alloc_init() - called by binder_open() for per-proc initialization
1073  * @alloc: binder_alloc for this proc
1074  *
1075  * Called from binder_open() to initialize binder_alloc fields for
1076  * new binder proc
1077  */
1078 void binder_alloc_init(struct binder_alloc *alloc)
1079 {
1080         alloc->pid = current->group_leader->pid;
1081         alloc->vma_vm_mm = current->mm;
1082         mmgrab(alloc->vma_vm_mm);
1083         mutex_init(&alloc->mutex);
1084         INIT_LIST_HEAD(&alloc->buffers);
1085 }
1086
1087 int binder_alloc_shrinker_init(void)
1088 {
1089         int ret = list_lru_init(&binder_alloc_lru);
1090
1091         if (ret == 0) {
1092                 ret = register_shrinker(&binder_shrinker, "android-binder");
1093                 if (ret)
1094                         list_lru_destroy(&binder_alloc_lru);
1095         }
1096         return ret;
1097 }
1098
1099 /**
1100  * check_buffer() - verify that buffer/offset is safe to access
1101  * @alloc: binder_alloc for this proc
1102  * @buffer: binder buffer to be accessed
1103  * @offset: offset into @buffer data
1104  * @bytes: bytes to access from offset
1105  *
1106  * Check that the @offset/@bytes are within the size of the given
1107  * @buffer and that the buffer is currently active and not freeable.
1108  * Offsets must also be multiples of sizeof(u32). The kernel is
1109  * allowed to touch the buffer in two cases:
1110  *
1111  * 1) when the buffer is being created:
1112  *     (buffer->free == 0 && buffer->allow_user_free == 0)
1113  * 2) when the buffer is being torn down:
1114  *     (buffer->free == 0 && buffer->transaction == NULL).
1115  *
1116  * Return: true if the buffer is safe to access
1117  */
1118 static inline bool check_buffer(struct binder_alloc *alloc,
1119                                 struct binder_buffer *buffer,
1120                                 binder_size_t offset, size_t bytes)
1121 {
1122         size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1123
1124         return buffer_size >= bytes &&
1125                 offset <= buffer_size - bytes &&
1126                 IS_ALIGNED(offset, sizeof(u32)) &&
1127                 !buffer->free &&
1128                 (!buffer->allow_user_free || !buffer->transaction);
1129 }
1130
1131 /**
1132  * binder_alloc_get_page() - get kernel pointer for given buffer offset
1133  * @alloc: binder_alloc for this proc
1134  * @buffer: binder buffer to be accessed
1135  * @buffer_offset: offset into @buffer data
1136  * @pgoffp: address to copy final page offset to
1137  *
1138  * Lookup the struct page corresponding to the address
1139  * at @buffer_offset into @buffer->user_data. If @pgoffp is not
1140  * NULL, the byte-offset into the page is written there.
1141  *
1142  * The caller is responsible to ensure that the offset points
1143  * to a valid address within the @buffer and that @buffer is
1144  * not freeable by the user. Since it can't be freed, we are
1145  * guaranteed that the corresponding elements of @alloc->pages[]
1146  * cannot change.
1147  *
1148  * Return: struct page
1149  */
1150 static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1151                                           struct binder_buffer *buffer,
1152                                           binder_size_t buffer_offset,
1153                                           pgoff_t *pgoffp)
1154 {
1155         binder_size_t buffer_space_offset = buffer_offset +
1156                 (buffer->user_data - alloc->buffer);
1157         pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
1158         size_t index = buffer_space_offset >> PAGE_SHIFT;
1159         struct binder_lru_page *lru_page;
1160
1161         lru_page = &alloc->pages[index];
1162         *pgoffp = pgoff;
1163         return lru_page->page_ptr;
1164 }
1165
1166 /**
1167  * binder_alloc_clear_buf() - zero out buffer
1168  * @alloc: binder_alloc for this proc
1169  * @buffer: binder buffer to be cleared
1170  *
1171  * memset the given buffer to 0
1172  */
1173 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
1174                                    struct binder_buffer *buffer)
1175 {
1176         size_t bytes = binder_alloc_buffer_size(alloc, buffer);
1177         binder_size_t buffer_offset = 0;
1178
1179         while (bytes) {
1180                 unsigned long size;
1181                 struct page *page;
1182                 pgoff_t pgoff;
1183
1184                 page = binder_alloc_get_page(alloc, buffer,
1185                                              buffer_offset, &pgoff);
1186                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1187                 memset_page(page, pgoff, 0, size);
1188                 bytes -= size;
1189                 buffer_offset += size;
1190         }
1191 }
1192
1193 /**
1194  * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1195  * @alloc: binder_alloc for this proc
1196  * @buffer: binder buffer to be accessed
1197  * @buffer_offset: offset into @buffer data
1198  * @from: userspace pointer to source buffer
1199  * @bytes: bytes to copy
1200  *
1201  * Copy bytes from source userspace to target buffer.
1202  *
1203  * Return: bytes remaining to be copied
1204  */
1205 unsigned long
1206 binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1207                                  struct binder_buffer *buffer,
1208                                  binder_size_t buffer_offset,
1209                                  const void __user *from,
1210                                  size_t bytes)
1211 {
1212         if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1213                 return bytes;
1214
1215         while (bytes) {
1216                 unsigned long size;
1217                 unsigned long ret;
1218                 struct page *page;
1219                 pgoff_t pgoff;
1220                 void *kptr;
1221
1222                 page = binder_alloc_get_page(alloc, buffer,
1223                                              buffer_offset, &pgoff);
1224                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1225                 kptr = kmap_local_page(page) + pgoff;
1226                 ret = copy_from_user(kptr, from, size);
1227                 kunmap_local(kptr);
1228                 if (ret)
1229                         return bytes - size + ret;
1230                 bytes -= size;
1231                 from += size;
1232                 buffer_offset += size;
1233         }
1234         return 0;
1235 }
1236
1237 static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1238                                        bool to_buffer,
1239                                        struct binder_buffer *buffer,
1240                                        binder_size_t buffer_offset,
1241                                        void *ptr,
1242                                        size_t bytes)
1243 {
1244         /* All copies must be 32-bit aligned and 32-bit size */
1245         if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1246                 return -EINVAL;
1247
1248         while (bytes) {
1249                 unsigned long size;
1250                 struct page *page;
1251                 pgoff_t pgoff;
1252
1253                 page = binder_alloc_get_page(alloc, buffer,
1254                                              buffer_offset, &pgoff);
1255                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1256                 if (to_buffer)
1257                         memcpy_to_page(page, pgoff, ptr, size);
1258                 else
1259                         memcpy_from_page(ptr, page, pgoff, size);
1260                 bytes -= size;
1261                 pgoff = 0;
1262                 ptr = ptr + size;
1263                 buffer_offset += size;
1264         }
1265         return 0;
1266 }
1267
1268 int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1269                                 struct binder_buffer *buffer,
1270                                 binder_size_t buffer_offset,
1271                                 void *src,
1272                                 size_t bytes)
1273 {
1274         return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1275                                            src, bytes);
1276 }
1277
1278 int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1279                                   void *dest,
1280                                   struct binder_buffer *buffer,
1281                                   binder_size_t buffer_offset,
1282                                   size_t bytes)
1283 {
1284         return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
1285                                            dest, bytes);
1286 }
1287