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