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                 alloc->vma_vm_mm = vma->vm_mm;
 326                 mmap_assert_write_locked(alloc->vma_vm_mm);
 327         } else {
 328                 mmap_assert_locked(alloc->vma_vm_mm);
 329         }
 330
 331         alloc->vma_addr = vm_start;
 332 }
 333
 334 static inline struct vm_area_struct *binder_alloc_get_vma(
 335                 struct binder_alloc *alloc)
 336 {
 337         struct vm_area_struct *vma = NULL;
 338
 339         if (alloc->vma_addr)
 340                 vma = vma_lookup(alloc->vma_vm_mm, alloc->vma_addr);
 341
 342         return vma;
 343 }
 344
 345 static bool debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
 346 {
 347         /*
 348          * Find the amount and size of buffers allocated by the current caller;
 349          * The idea is that once we cross the threshold, whoever is responsible
 350          * for the low async space is likely to try to send another async txn,
 351          * and at some point we'll catch them in the act. This is more efficient
 352          * than keeping a map per pid.
 353          */
 354         struct rb_node *n;
 355         struct binder_buffer *buffer;
 356         size_t total_alloc_size = 0;
 357         size_t num_buffers = 0;
 358
 359         for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 360                  n = rb_next(n)) {
 361                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 362                 if (buffer->pid != pid)
 363                         continue;
 364                 if (!buffer->async_transaction)
 365                         continue;
 366                 total_alloc_size += binder_alloc_buffer_size(alloc, buffer)
 367                         + sizeof(struct binder_buffer);
 368                 num_buffers++;
 369         }
 370
 371         /*
 372          * Warn if this pid has more than 50 transactions, or more than 50% of
 373          * async space (which is 25% of total buffer size). Oneway spam is only
 374          * detected when the threshold is exceeded.
 375          */
 376         if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) {
 377                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 378                              "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n",
 379                               alloc->pid, pid, num_buffers, total_alloc_size);
 380                 if (!alloc->oneway_spam_detected) {
 381                         alloc->oneway_spam_detected = true;
 382                         return true;
 383                 }
 384         }
 385         return false;
 386 }
 387
 388 static struct binder_buffer *binder_alloc_new_buf_locked(
 389                                 struct binder_alloc *alloc,
 390                                 size_t data_size,
 391                                 size_t offsets_size,
 392                                 size_t extra_buffers_size,
 393                                 int is_async,
 394                                 int pid)
 395 {
 396         struct rb_node *n = alloc->free_buffers.rb_node;
 397         struct binder_buffer *buffer;
 398         size_t buffer_size;
 399         struct rb_node *best_fit = NULL;
 400         void __user *has_page_addr;
 401         void __user *end_page_addr;
 402         size_t size, data_offsets_size;
 403         int ret;
 404
 405         mmap_read_lock(alloc->vma_vm_mm);
 406         if (!binder_alloc_get_vma(alloc)) {
 407                 mmap_read_unlock(alloc->vma_vm_mm);
 408                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 409                                    "%d: binder_alloc_buf, no vma\n",
 410                                    alloc->pid);
 411                 return ERR_PTR(-ESRCH);
 412         }
 413         mmap_read_unlock(alloc->vma_vm_mm);
 414
 415         data_offsets_size = ALIGN(data_size, sizeof(void *)) +
 416                 ALIGN(offsets_size, sizeof(void *));
 417
 418         if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
 419                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 420                                 "%d: got transaction with invalid size %zd-%zd\n",
 421                                 alloc->pid, data_size, offsets_size);
 422                 return ERR_PTR(-EINVAL);
 423         }
 424         size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
 425         if (size < data_offsets_size || size < extra_buffers_size) {
 426                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 427                                 "%d: got transaction with invalid extra_buffers_size %zd\n",
 428                                 alloc->pid, extra_buffers_size);
 429                 return ERR_PTR(-EINVAL);
 430         }
 431         if (is_async &&
 432             alloc->free_async_space < size + sizeof(struct binder_buffer)) {
 433                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 434                              "%d: binder_alloc_buf size %zd failed, no async space left\n",
 435                               alloc->pid, size);
 436                 return ERR_PTR(-ENOSPC);
 437         }
 438
 439         /* Pad 0-size buffers so they get assigned unique addresses */
 440         size = max(size, sizeof(void *));
 441
 442         while (n) {
 443                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 444                 BUG_ON(!buffer->free);
 445                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 446
 447                 if (size < buffer_size) {
 448                         best_fit = n;
 449                         n = n->rb_left;
 450                 } else if (size > buffer_size)
 451                         n = n->rb_right;
 452                 else {
 453                         best_fit = n;
 454                         break;
 455                 }
 456         }
 457         if (best_fit == NULL) {
 458                 size_t allocated_buffers = 0;
 459                 size_t largest_alloc_size = 0;
 460                 size_t total_alloc_size = 0;
 461                 size_t free_buffers = 0;
 462                 size_t largest_free_size = 0;
 463                 size_t total_free_size = 0;
 464
 465                 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 466                      n = rb_next(n)) {
 467                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 468                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 469                         allocated_buffers++;
 470                         total_alloc_size += buffer_size;
 471                         if (buffer_size > largest_alloc_size)
 472                                 largest_alloc_size = buffer_size;
 473                 }
 474                 for (n = rb_first(&alloc->free_buffers); n != NULL;
 475                      n = rb_next(n)) {
 476                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 477                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 478                         free_buffers++;
 479                         total_free_size += buffer_size;
 480                         if (buffer_size > largest_free_size)
 481                                 largest_free_size = buffer_size;
 482                 }
 483                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 484                                    "%d: binder_alloc_buf size %zd failed, no address space\n",
 485                                    alloc->pid, size);
 486                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 487                                    "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
 488                                    total_alloc_size, allocated_buffers,
 489                                    largest_alloc_size, total_free_size,
 490                                    free_buffers, largest_free_size);
 491                 return ERR_PTR(-ENOSPC);
 492         }
 493         if (n == NULL) {
 494                 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
 495                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 496         }
 497
 498         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 499                      "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
 500                       alloc->pid, size, buffer, buffer_size);
 501
 502         has_page_addr = (void __user *)
 503                 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
 504         WARN_ON(n && buffer_size != size);
 505         end_page_addr =
 506                 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
 507         if (end_page_addr > has_page_addr)
 508                 end_page_addr = has_page_addr;
 509         ret = binder_update_page_range(alloc, 1, (void __user *)
 510                 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
 511         if (ret)
 512                 return ERR_PTR(ret);
 513
 514         if (buffer_size != size) {
 515                 struct binder_buffer *new_buffer;
 516
 517                 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 518                 if (!new_buffer) {
 519                         pr_err("%s: %d failed to alloc new buffer struct\n",
 520                                __func__, alloc->pid);
 521                         goto err_alloc_buf_struct_failed;
 522                 }
 523                 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
 524                 list_add(&new_buffer->entry, &buffer->entry);
 525                 new_buffer->free = 1;
 526                 binder_insert_free_buffer(alloc, new_buffer);
 527         }
 528
 529         rb_erase(best_fit, &alloc->free_buffers);
 530         buffer->free = 0;
 531         buffer->allow_user_free = 0;
 532         binder_insert_allocated_buffer_locked(alloc, buffer);
 533         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 534                      "%d: binder_alloc_buf size %zd got %pK\n",
 535                       alloc->pid, size, buffer);
 536         buffer->data_size = data_size;
 537         buffer->offsets_size = offsets_size;
 538         buffer->async_transaction = is_async;
 539         buffer->extra_buffers_size = extra_buffers_size;
 540         buffer->pid = pid;
 541         buffer->oneway_spam_suspect = false;
 542         if (is_async) {
 543                 alloc->free_async_space -= size + sizeof(struct binder_buffer);
 544                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 545                              "%d: binder_alloc_buf size %zd async free %zd\n",
 546                               alloc->pid, size, alloc->free_async_space);
 547                 if (alloc->free_async_space < alloc->buffer_size / 10) {
 548                         /*
 549                          * Start detecting spammers once we have less than 20%
 550                          * of async space left (which is less than 10% of total
 551                          * buffer size).
 552                          */
 553                         buffer->oneway_spam_suspect = debug_low_async_space_locked(alloc, pid);
 554                 } else {
 555                         alloc->oneway_spam_detected = false;
 556                 }
 557         }
 558         return buffer;
 559
 560 err_alloc_buf_struct_failed:
 561         binder_update_page_range(alloc, 0, (void __user *)
 562                                  PAGE_ALIGN((uintptr_t)buffer->user_data),
 563                                  end_page_addr);
 564         return ERR_PTR(-ENOMEM);
 565 }
 566
 567 /**
 568  * binder_alloc_new_buf() - Allocate a new binder buffer
 569  * @alloc:              binder_alloc for this proc
 570  * @data_size:          size of user data buffer
 571  * @offsets_size:       user specified buffer offset
 572  * @extra_buffers_size: size of extra space for meta-data (eg, security context)
 573  * @is_async:           buffer for async transaction
 574  * @pid:                                pid to attribute allocation to (used for debugging)
 575  *
 576  * Allocate a new buffer given the requested sizes. Returns
 577  * the kernel version of the buffer pointer. The size allocated
 578  * is the sum of the three given sizes (each rounded up to
 579  * pointer-sized boundary)
 580  *
 581  * Return:      The allocated buffer or %NULL if error
 582  */
 583 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 584                                            size_t data_size,
 585                                            size_t offsets_size,
 586                                            size_t extra_buffers_size,
 587                                            int is_async,
 588                                            int pid)
 589 {
 590         struct binder_buffer *buffer;
 591
 592         mutex_lock(&alloc->mutex);
 593         buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
 594                                              extra_buffers_size, is_async, pid);
 595         mutex_unlock(&alloc->mutex);
 596         return buffer;
 597 }
 598
 599 static void __user *buffer_start_page(struct binder_buffer *buffer)
 600 {
 601         return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
 602 }
 603
 604 static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
 605 {
 606         return (void __user *)
 607                 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
 608 }
 609
 610 static void binder_delete_free_buffer(struct binder_alloc *alloc,
 611                                       struct binder_buffer *buffer)
 612 {
 613         struct binder_buffer *prev, *next = NULL;
 614         bool to_free = true;
 615
 616         BUG_ON(alloc->buffers.next == &buffer->entry);
 617         prev = binder_buffer_prev(buffer);
 618         BUG_ON(!prev->free);
 619         if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
 620                 to_free = false;
 621                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 622                                    "%d: merge free, buffer %pK share page with %pK\n",
 623                                    alloc->pid, buffer->user_data,
 624                                    prev->user_data);
 625         }
 626
 627         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 628                 next = binder_buffer_next(buffer);
 629                 if (buffer_start_page(next) == buffer_start_page(buffer)) {
 630                         to_free = false;
 631                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 632                                            "%d: merge free, buffer %pK share page with %pK\n",
 633                                            alloc->pid,
 634                                            buffer->user_data,
 635                                            next->user_data);
 636                 }
 637         }
 638
 639         if (PAGE_ALIGNED(buffer->user_data)) {
 640                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 641                                    "%d: merge free, buffer start %pK is page aligned\n",
 642                                    alloc->pid, buffer->user_data);
 643                 to_free = false;
 644         }
 645
 646         if (to_free) {
 647                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 648                                    "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
 649                                    alloc->pid, buffer->user_data,
 650                                    prev->user_data,
 651                                    next ? next->user_data : NULL);
 652                 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
 653                                          buffer_start_page(buffer) + PAGE_SIZE);
 654         }
 655         list_del(&buffer->entry);
 656         kfree(buffer);
 657 }
 658
 659 static void binder_free_buf_locked(struct binder_alloc *alloc,
 660                                    struct binder_buffer *buffer)
 661 {
 662         size_t size, buffer_size;
 663
 664         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 665
 666         size = ALIGN(buffer->data_size, sizeof(void *)) +
 667                 ALIGN(buffer->offsets_size, sizeof(void *)) +
 668                 ALIGN(buffer->extra_buffers_size, sizeof(void *));
 669
 670         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 671                      "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
 672                       alloc->pid, buffer, size, buffer_size);
 673
 674         BUG_ON(buffer->free);
 675         BUG_ON(size > buffer_size);
 676         BUG_ON(buffer->transaction != NULL);
 677         BUG_ON(buffer->user_data < alloc->buffer);
 678         BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
 679
 680         if (buffer->async_transaction) {
 681                 alloc->free_async_space += buffer_size + sizeof(struct binder_buffer);
 682
 683                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 684                              "%d: binder_free_buf size %zd async free %zd\n",
 685                               alloc->pid, size, alloc->free_async_space);
 686         }
 687
 688         binder_update_page_range(alloc, 0,
 689                 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
 690                 (void __user *)(((uintptr_t)
 691                           buffer->user_data + buffer_size) & PAGE_MASK));
 692
 693         rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
 694         buffer->free = 1;
 695         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 696                 struct binder_buffer *next = binder_buffer_next(buffer);
 697
 698                 if (next->free) {
 699                         rb_erase(&next->rb_node, &alloc->free_buffers);
 700                         binder_delete_free_buffer(alloc, next);
 701                 }
 702         }
 703         if (alloc->buffers.next != &buffer->entry) {
 704                 struct binder_buffer *prev = binder_buffer_prev(buffer);
 705
 706                 if (prev->free) {
 707                         binder_delete_free_buffer(alloc, buffer);
 708                         rb_erase(&prev->rb_node, &alloc->free_buffers);
 709                         buffer = prev;
 710                 }
 711         }
 712         binder_insert_free_buffer(alloc, buffer);
 713 }
 714
 715 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
 716                                    struct binder_buffer *buffer);
 717 /**
 718  * binder_alloc_free_buf() - free a binder buffer
 719  * @alloc:      binder_alloc for this proc
 720  * @buffer:     kernel pointer to buffer
 721  *
 722  * Free the buffer allocated via binder_alloc_new_buf()
 723  */
 724 void binder_alloc_free_buf(struct binder_alloc *alloc,
 725                             struct binder_buffer *buffer)
 726 {
 727         /*
 728          * We could eliminate the call to binder_alloc_clear_buf()
 729          * from binder_alloc_deferred_release() by moving this to
 730          * binder_alloc_free_buf_locked(). However, that could
 731          * increase contention for the alloc mutex if clear_on_free
 732          * is used frequently for large buffers. The mutex is not
 733          * needed for correctness here.
 734          */
 735         if (buffer->clear_on_free) {
 736                 binder_alloc_clear_buf(alloc, buffer);
 737                 buffer->clear_on_free = false;
 738         }
 739         mutex_lock(&alloc->mutex);
 740         binder_free_buf_locked(alloc, buffer);
 741         mutex_unlock(&alloc->mutex);
 742 }
 743
 744 /**
 745  * binder_alloc_mmap_handler() - map virtual address space for proc
 746  * @alloc:      alloc structure for this proc
 747  * @vma:        vma passed to mmap()
 748  *
 749  * Called by binder_mmap() to initialize the space specified in
 750  * vma for allocating binder buffers
 751  *
 752  * Return:
 753  *      0 = success
 754  *      -EBUSY = address space already mapped
 755  *      -ENOMEM = failed to map memory to given address space
 756  */
 757 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 758                               struct vm_area_struct *vma)
 759 {
 760         int ret;
 761         const char *failure_string;
 762         struct binder_buffer *buffer;
 763
 764         mutex_lock(&binder_alloc_mmap_lock);
 765         if (alloc->buffer_size) {
 766                 ret = -EBUSY;
 767                 failure_string = "already mapped";
 768                 goto err_already_mapped;
 769         }
 770         alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
 771                                    SZ_4M);
 772         mutex_unlock(&binder_alloc_mmap_lock);
 773
 774         alloc->buffer = (void __user *)vma->vm_start;
 775
 776         alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
 777                                sizeof(alloc->pages[0]),
 778                                GFP_KERNEL);
 779         if (alloc->pages == NULL) {
 780                 ret = -ENOMEM;
 781                 failure_string = "alloc page array";
 782                 goto err_alloc_pages_failed;
 783         }
 784
 785         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 786         if (!buffer) {
 787                 ret = -ENOMEM;
 788                 failure_string = "alloc buffer struct";
 789                 goto err_alloc_buf_struct_failed;
 790         }
 791
 792         buffer->user_data = alloc->buffer;
 793         list_add(&buffer->entry, &alloc->buffers);
 794         buffer->free = 1;
 795         binder_insert_free_buffer(alloc, buffer);
 796         alloc->free_async_space = alloc->buffer_size / 2;
 797         binder_alloc_set_vma(alloc, vma);
 798         mmgrab(alloc->vma_vm_mm);
 799
 800         return 0;
 801
 802 err_alloc_buf_struct_failed:
 803         kfree(alloc->pages);
 804         alloc->pages = NULL;
 805 err_alloc_pages_failed:
 806         alloc->buffer = NULL;
 807         mutex_lock(&binder_alloc_mmap_lock);
 808         alloc->buffer_size = 0;
 809 err_already_mapped:
 810         mutex_unlock(&binder_alloc_mmap_lock);
 811         binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 812                            "%s: %d %lx-%lx %s failed %d\n", __func__,
 813                            alloc->pid, vma->vm_start, vma->vm_end,
 814                            failure_string, ret);
 815         return ret;
 816 }
 817
 818
 819 void binder_alloc_deferred_release(struct binder_alloc *alloc)
 820 {
 821         struct rb_node *n;
 822         int buffers, page_count;
 823         struct binder_buffer *buffer;
 824
 825         buffers = 0;
 826         mutex_lock(&alloc->mutex);
 827         BUG_ON(alloc->vma_addr &&
 828                vma_lookup(alloc->vma_vm_mm, alloc->vma_addr));
 829
 830         while ((n = rb_first(&alloc->allocated_buffers))) {
 831                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 832
 833                 /* Transaction should already have been freed */
 834                 BUG_ON(buffer->transaction);
 835
 836                 if (buffer->clear_on_free) {
 837                         binder_alloc_clear_buf(alloc, buffer);
 838                         buffer->clear_on_free = false;
 839                 }
 840                 binder_free_buf_locked(alloc, buffer);
 841                 buffers++;
 842         }
 843
 844         while (!list_empty(&alloc->buffers)) {
 845                 buffer = list_first_entry(&alloc->buffers,
 846                                           struct binder_buffer, entry);
 847                 WARN_ON(!buffer->free);
 848
 849                 list_del(&buffer->entry);
 850                 WARN_ON_ONCE(!list_empty(&alloc->buffers));
 851                 kfree(buffer);
 852         }
 853
 854         page_count = 0;
 855         if (alloc->pages) {
 856                 int i;
 857
 858                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 859                         void __user *page_addr;
 860                         bool on_lru;
 861
 862                         if (!alloc->pages[i].page_ptr)
 863                                 continue;
 864
 865                         on_lru = list_lru_del(&binder_alloc_lru,
 866                                               &alloc->pages[i].lru);
 867                         page_addr = alloc->buffer + i * PAGE_SIZE;
 868                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 869                                      "%s: %d: page %d at %pK %s\n",
 870                                      __func__, alloc->pid, i, page_addr,
 871                                      on_lru ? "on lru" : "active");
 872                         __free_page(alloc->pages[i].page_ptr);
 873                         page_count++;
 874                 }
 875                 kfree(alloc->pages);
 876         }
 877         mutex_unlock(&alloc->mutex);
 878         if (alloc->vma_vm_mm)
 879                 mmdrop(alloc->vma_vm_mm);
 880
 881         binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
 882                      "%s: %d buffers %d, pages %d\n",
 883                      __func__, alloc->pid, buffers, page_count);
 884 }
 885
 886 static void print_binder_buffer(struct seq_file *m, const char *prefix,
 887                                 struct binder_buffer *buffer)
 888 {
 889         seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
 890                    prefix, buffer->debug_id, buffer->user_data,
 891                    buffer->data_size, buffer->offsets_size,
 892                    buffer->extra_buffers_size,
 893                    buffer->transaction ? "active" : "delivered");
 894 }
 895
 896 /**
 897  * binder_alloc_print_allocated() - print buffer info
 898  * @m:     seq_file for output via seq_printf()
 899  * @alloc: binder_alloc for this proc
 900  *
 901  * Prints information about every buffer associated with
 902  * the binder_alloc state to the given seq_file
 903  */
 904 void binder_alloc_print_allocated(struct seq_file *m,
 905                                   struct binder_alloc *alloc)
 906 {
 907         struct rb_node *n;
 908
 909         mutex_lock(&alloc->mutex);
 910         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 911                 print_binder_buffer(m, "  buffer",
 912                                     rb_entry(n, struct binder_buffer, rb_node));
 913         mutex_unlock(&alloc->mutex);
 914 }
 915
 916 /**
 917  * binder_alloc_print_pages() - print page usage
 918  * @m:     seq_file for output via seq_printf()
 919  * @alloc: binder_alloc for this proc
 920  */
 921 void binder_alloc_print_pages(struct seq_file *m,
 922                               struct binder_alloc *alloc)
 923 {
 924         struct binder_lru_page *page;
 925         int i;
 926         int active = 0;
 927         int lru = 0;
 928         int free = 0;
 929
 930         mutex_lock(&alloc->mutex);
 931         /*
 932          * Make sure the binder_alloc is fully initialized, otherwise we might
 933          * read inconsistent state.
 934          */
 935
 936         mmap_read_lock(alloc->vma_vm_mm);
 937         if (binder_alloc_get_vma(alloc) == NULL) {
 938                 mmap_read_unlock(alloc->vma_vm_mm);
 939                 goto uninitialized;
 940         }
 941
 942         mmap_read_unlock(alloc->vma_vm_mm);
 943         for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 944                 page = &alloc->pages[i];
 945                 if (!page->page_ptr)
 946                         free++;
 947                 else if (list_empty(&page->lru))
 948                         active++;
 949                 else
 950                         lru++;
 951         }
 952
 953 uninitialized:
 954         mutex_unlock(&alloc->mutex);
 955         seq_printf(m, "  pages: %d:%d:%d\n", active, lru, free);
 956         seq_printf(m, "  pages high watermark: %zu\n", alloc->pages_high);
 957 }
 958
 959 /**
 960  * binder_alloc_get_allocated_count() - return count of buffers
 961  * @alloc: binder_alloc for this proc
 962  *
 963  * Return: count of allocated buffers
 964  */
 965 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
 966 {
 967         struct rb_node *n;
 968         int count = 0;
 969
 970         mutex_lock(&alloc->mutex);
 971         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 972                 count++;
 973         mutex_unlock(&alloc->mutex);
 974         return count;
 975 }
 976
 977
 978 /**
 979  * binder_alloc_vma_close() - invalidate address space
 980  * @alloc: binder_alloc for this proc
 981  *
 982  * Called from binder_vma_close() when releasing address space.
 983  * Clears alloc->vma to prevent new incoming transactions from
 984  * allocating more buffers.
 985  */
 986 void binder_alloc_vma_close(struct binder_alloc *alloc)
 987 {
 988         binder_alloc_set_vma(alloc, NULL);
 989 }
 990
 991 /**
 992  * binder_alloc_free_page() - shrinker callback to free pages
 993  * @item:   item to free
 994  * @lock:   lock protecting the item
 995  * @cb_arg: callback argument
 996  *
 997  * Called from list_lru_walk() in binder_shrink_scan() to free
 998  * up pages when the system is under memory pressure.
 999  */
1000 enum lru_status binder_alloc_free_page(struct list_head *item,
1001                                        struct list_lru_one *lru,
1002                                        spinlock_t *lock,
1003                                        void *cb_arg)
1004         __must_hold(lock)
1005 {
1006         struct mm_struct *mm = NULL;
1007         struct binder_lru_page *page = container_of(item,
1008                                                     struct binder_lru_page,
1009                                                     lru);
1010         struct binder_alloc *alloc;
1011         uintptr_t page_addr;
1012         size_t index;
1013         struct vm_area_struct *vma;
1014
1015         alloc = page->alloc;
1016         if (!mutex_trylock(&alloc->mutex))
1017                 goto err_get_alloc_mutex_failed;
1018
1019         if (!page->page_ptr)
1020                 goto err_page_already_freed;
1021
1022         index = page - alloc->pages;
1023         page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
1024
1025         mm = alloc->vma_vm_mm;
1026         if (!mmget_not_zero(mm))
1027                 goto err_mmget;
1028         if (!mmap_read_trylock(mm))
1029                 goto err_mmap_read_lock_failed;
1030         vma = binder_alloc_get_vma(alloc);
1031
1032         list_lru_isolate(lru, item);
1033         spin_unlock(lock);
1034
1035         if (vma) {
1036                 trace_binder_unmap_user_start(alloc, index);
1037
1038                 zap_page_range(vma, page_addr, PAGE_SIZE);
1039
1040                 trace_binder_unmap_user_end(alloc, index);
1041         }
1042         mmap_read_unlock(mm);
1043         mmput_async(mm);
1044
1045         trace_binder_unmap_kernel_start(alloc, index);
1046
1047         __free_page(page->page_ptr);
1048         page->page_ptr = NULL;
1049
1050         trace_binder_unmap_kernel_end(alloc, index);
1051
1052         spin_lock(lock);
1053         mutex_unlock(&alloc->mutex);
1054         return LRU_REMOVED_RETRY;
1055
1056 err_mmap_read_lock_failed:
1057         mmput_async(mm);
1058 err_mmget:
1059 err_page_already_freed:
1060         mutex_unlock(&alloc->mutex);
1061 err_get_alloc_mutex_failed:
1062         return LRU_SKIP;
1063 }
1064
1065 static unsigned long
1066 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
1067 {
1068         return list_lru_count(&binder_alloc_lru);
1069 }
1070
1071 static unsigned long
1072 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1073 {
1074         return list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
1075                             NULL, sc->nr_to_scan);
1076 }
1077
1078 static struct shrinker binder_shrinker = {
1079         .count_objects = binder_shrink_count,
1080         .scan_objects = binder_shrink_scan,
1081         .seeks = DEFAULT_SEEKS,
1082 };
1083
1084 /**
1085  * binder_alloc_init() - called by binder_open() for per-proc initialization
1086  * @alloc: binder_alloc for this proc
1087  *
1088  * Called from binder_open() to initialize binder_alloc fields for
1089  * new binder proc
1090  */
1091 void binder_alloc_init(struct binder_alloc *alloc)
1092 {
1093         alloc->pid = current->group_leader->pid;
1094         mutex_init(&alloc->mutex);
1095         INIT_LIST_HEAD(&alloc->buffers);
1096 }
1097
1098 int binder_alloc_shrinker_init(void)
1099 {
1100         int ret = list_lru_init(&binder_alloc_lru);
1101
1102         if (ret == 0) {
1103                 ret = register_shrinker(&binder_shrinker, "android-binder");
1104                 if (ret)
1105                         list_lru_destroy(&binder_alloc_lru);
1106         }
1107         return ret;
1108 }
1109
1110 /**
1111  * check_buffer() - verify that buffer/offset is safe to access
1112  * @alloc: binder_alloc for this proc
1113  * @buffer: binder buffer to be accessed
1114  * @offset: offset into @buffer data
1115  * @bytes: bytes to access from offset
1116  *
1117  * Check that the @offset/@bytes are within the size of the given
1118  * @buffer and that the buffer is currently active and not freeable.
1119  * Offsets must also be multiples of sizeof(u32). The kernel is
1120  * allowed to touch the buffer in two cases:
1121  *
1122  * 1) when the buffer is being created:
1123  *     (buffer->free == 0 && buffer->allow_user_free == 0)
1124  * 2) when the buffer is being torn down:
1125  *     (buffer->free == 0 && buffer->transaction == NULL).
1126  *
1127  * Return: true if the buffer is safe to access
1128  */
1129 static inline bool check_buffer(struct binder_alloc *alloc,
1130                                 struct binder_buffer *buffer,
1131                                 binder_size_t offset, size_t bytes)
1132 {
1133         size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1134
1135         return buffer_size >= bytes &&
1136                 offset <= buffer_size - bytes &&
1137                 IS_ALIGNED(offset, sizeof(u32)) &&
1138                 !buffer->free &&
1139                 (!buffer->allow_user_free || !buffer->transaction);
1140 }
1141
1142 /**
1143  * binder_alloc_get_page() - get kernel pointer for given buffer offset
1144  * @alloc: binder_alloc for this proc
1145  * @buffer: binder buffer to be accessed
1146  * @buffer_offset: offset into @buffer data
1147  * @pgoffp: address to copy final page offset to
1148  *
1149  * Lookup the struct page corresponding to the address
1150  * at @buffer_offset into @buffer->user_data. If @pgoffp is not
1151  * NULL, the byte-offset into the page is written there.
1152  *
1153  * The caller is responsible to ensure that the offset points
1154  * to a valid address within the @buffer and that @buffer is
1155  * not freeable by the user. Since it can't be freed, we are
1156  * guaranteed that the corresponding elements of @alloc->pages[]
1157  * cannot change.
1158  *
1159  * Return: struct page
1160  */
1161 static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1162                                           struct binder_buffer *buffer,
1163                                           binder_size_t buffer_offset,
1164                                           pgoff_t *pgoffp)
1165 {
1166         binder_size_t buffer_space_offset = buffer_offset +
1167                 (buffer->user_data - alloc->buffer);
1168         pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
1169         size_t index = buffer_space_offset >> PAGE_SHIFT;
1170         struct binder_lru_page *lru_page;
1171
1172         lru_page = &alloc->pages[index];
1173         *pgoffp = pgoff;
1174         return lru_page->page_ptr;
1175 }
1176
1177 /**
1178  * binder_alloc_clear_buf() - zero out buffer
1179  * @alloc: binder_alloc for this proc
1180  * @buffer: binder buffer to be cleared
1181  *
1182  * memset the given buffer to 0
1183  */
1184 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
1185                                    struct binder_buffer *buffer)
1186 {
1187         size_t bytes = binder_alloc_buffer_size(alloc, buffer);
1188         binder_size_t buffer_offset = 0;
1189
1190         while (bytes) {
1191                 unsigned long size;
1192                 struct page *page;
1193                 pgoff_t pgoff;
1194
1195                 page = binder_alloc_get_page(alloc, buffer,
1196                                              buffer_offset, &pgoff);
1197                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1198                 memset_page(page, pgoff, 0, size);
1199                 bytes -= size;
1200                 buffer_offset += size;
1201         }
1202 }
1203
1204 /**
1205  * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1206  * @alloc: binder_alloc for this proc
1207  * @buffer: binder buffer to be accessed
1208  * @buffer_offset: offset into @buffer data
1209  * @from: userspace pointer to source buffer
1210  * @bytes: bytes to copy
1211  *
1212  * Copy bytes from source userspace to target buffer.
1213  *
1214  * Return: bytes remaining to be copied
1215  */
1216 unsigned long
1217 binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1218                                  struct binder_buffer *buffer,
1219                                  binder_size_t buffer_offset,
1220                                  const void __user *from,
1221                                  size_t bytes)
1222 {
1223         if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1224                 return bytes;
1225
1226         while (bytes) {
1227                 unsigned long size;
1228                 unsigned long ret;
1229                 struct page *page;
1230                 pgoff_t pgoff;
1231                 void *kptr;
1232
1233                 page = binder_alloc_get_page(alloc, buffer,
1234                                              buffer_offset, &pgoff);
1235                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1236                 kptr = kmap_local_page(page) + pgoff;
1237                 ret = copy_from_user(kptr, from, size);
1238                 kunmap_local(kptr);
1239                 if (ret)
1240                         return bytes - size + ret;
1241                 bytes -= size;
1242                 from += size;
1243                 buffer_offset += size;
1244         }
1245         return 0;
1246 }
1247
1248 static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1249                                        bool to_buffer,
1250                                        struct binder_buffer *buffer,
1251                                        binder_size_t buffer_offset,
1252                                        void *ptr,
1253                                        size_t bytes)
1254 {
1255         /* All copies must be 32-bit aligned and 32-bit size */
1256         if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1257                 return -EINVAL;
1258
1259         while (bytes) {
1260                 unsigned long size;
1261                 struct page *page;
1262                 pgoff_t pgoff;
1263
1264                 page = binder_alloc_get_page(alloc, buffer,
1265                                              buffer_offset, &pgoff);
1266                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1267                 if (to_buffer)
1268                         memcpy_to_page(page, pgoff, ptr, size);
1269                 else
1270                         memcpy_from_page(ptr, page, pgoff, size);
1271                 bytes -= size;
1272                 pgoff = 0;
1273                 ptr = ptr + size;
1274                 buffer_offset += size;
1275         }
1276         return 0;
1277 }
1278
1279 int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1280                                 struct binder_buffer *buffer,
1281                                 binder_size_t buffer_offset,
1282                                 void *src,
1283                                 size_t bytes)
1284 {
1285         return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1286                                            src, bytes);
1287 }
1288
1289 int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1290                                   void *dest,
1291                                   struct binder_buffer *buffer,
1292                                   binder_size_t buffer_offset,
1293                                   size_t bytes)
1294 {
1295         return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
1296                                            dest, bytes);
1297 }
1298