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         if (vma) {
 319                 vm_start = vma->vm_start;
 320                 mmap_assert_write_locked(alloc->vma_vm_mm);
 321         }
 322
 323         alloc->vma_addr = vm_start;
 324 }
 325
 326 static inline struct vm_area_struct *binder_alloc_get_vma(
 327                 struct binder_alloc *alloc)
 328 {
 329         struct vm_area_struct *vma = NULL;
 330
 331         if (alloc->vma_addr)
 332                 vma = vma_lookup(alloc->vma_vm_mm, alloc->vma_addr);
 333
 334         return vma;
 335 }
 336
 337 static bool debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
 338 {
 339         /*
 340          * Find the amount and size of buffers allocated by the current caller;
 341          * The idea is that once we cross the threshold, whoever is responsible
 342          * for the low async space is likely to try to send another async txn,
 343          * and at some point we'll catch them in the act. This is more efficient
 344          * than keeping a map per pid.
 345          */
 346         struct rb_node *n;
 347         struct binder_buffer *buffer;
 348         size_t total_alloc_size = 0;
 349         size_t num_buffers = 0;
 350
 351         for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 352                  n = rb_next(n)) {
 353                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 354                 if (buffer->pid != pid)
 355                         continue;
 356                 if (!buffer->async_transaction)
 357                         continue;
 358                 total_alloc_size += binder_alloc_buffer_size(alloc, buffer)
 359                         + sizeof(struct binder_buffer);
 360                 num_buffers++;
 361         }
 362
 363         /*
 364          * Warn if this pid has more than 50 transactions, or more than 50% of
 365          * async space (which is 25% of total buffer size). Oneway spam is only
 366          * detected when the threshold is exceeded.
 367          */
 368         if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) {
 369                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 370                              "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n",
 371                               alloc->pid, pid, num_buffers, total_alloc_size);
 372                 if (!alloc->oneway_spam_detected) {
 373                         alloc->oneway_spam_detected = true;
 374                         return true;
 375                 }
 376         }
 377         return false;
 378 }
 379
 380 static struct binder_buffer *binder_alloc_new_buf_locked(
 381                                 struct binder_alloc *alloc,
 382                                 size_t data_size,
 383                                 size_t offsets_size,
 384                                 size_t extra_buffers_size,
 385                                 int is_async,
 386                                 int pid)
 387 {
 388         struct rb_node *n = alloc->free_buffers.rb_node;
 389         struct binder_buffer *buffer;
 390         size_t buffer_size;
 391         struct rb_node *best_fit = NULL;
 392         void __user *has_page_addr;
 393         void __user *end_page_addr;
 394         size_t size, data_offsets_size;
 395         int ret;
 396
 397         mmap_read_lock(alloc->vma_vm_mm);
 398         if (!binder_alloc_get_vma(alloc)) {
 399                 mmap_read_unlock(alloc->vma_vm_mm);
 400                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 401                                    "%d: binder_alloc_buf, no vma\n",
 402                                    alloc->pid);
 403                 return ERR_PTR(-ESRCH);
 404         }
 405         mmap_read_unlock(alloc->vma_vm_mm);
 406
 407         data_offsets_size = ALIGN(data_size, sizeof(void *)) +
 408                 ALIGN(offsets_size, sizeof(void *));
 409
 410         if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
 411                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 412                                 "%d: got transaction with invalid size %zd-%zd\n",
 413                                 alloc->pid, data_size, offsets_size);
 414                 return ERR_PTR(-EINVAL);
 415         }
 416         size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
 417         if (size < data_offsets_size || size < extra_buffers_size) {
 418                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 419                                 "%d: got transaction with invalid extra_buffers_size %zd\n",
 420                                 alloc->pid, extra_buffers_size);
 421                 return ERR_PTR(-EINVAL);
 422         }
 423         if (is_async &&
 424             alloc->free_async_space < size + sizeof(struct binder_buffer)) {
 425                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 426                              "%d: binder_alloc_buf size %zd failed, no async space left\n",
 427                               alloc->pid, size);
 428                 return ERR_PTR(-ENOSPC);
 429         }
 430
 431         /* Pad 0-size buffers so they get assigned unique addresses */
 432         size = max(size, sizeof(void *));
 433
 434         while (n) {
 435                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 436                 BUG_ON(!buffer->free);
 437                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 438
 439                 if (size < buffer_size) {
 440                         best_fit = n;
 441                         n = n->rb_left;
 442                 } else if (size > buffer_size)
 443                         n = n->rb_right;
 444                 else {
 445                         best_fit = n;
 446                         break;
 447                 }
 448         }
 449         if (best_fit == NULL) {
 450                 size_t allocated_buffers = 0;
 451                 size_t largest_alloc_size = 0;
 452                 size_t total_alloc_size = 0;
 453                 size_t free_buffers = 0;
 454                 size_t largest_free_size = 0;
 455                 size_t total_free_size = 0;
 456
 457                 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 458                      n = rb_next(n)) {
 459                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 460                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 461                         allocated_buffers++;
 462                         total_alloc_size += buffer_size;
 463                         if (buffer_size > largest_alloc_size)
 464                                 largest_alloc_size = buffer_size;
 465                 }
 466                 for (n = rb_first(&alloc->free_buffers); n != NULL;
 467                      n = rb_next(n)) {
 468                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 469                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 470                         free_buffers++;
 471                         total_free_size += buffer_size;
 472                         if (buffer_size > largest_free_size)
 473                                 largest_free_size = buffer_size;
 474                 }
 475                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 476                                    "%d: binder_alloc_buf size %zd failed, no address space\n",
 477                                    alloc->pid, size);
 478                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 479                                    "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
 480                                    total_alloc_size, allocated_buffers,
 481                                    largest_alloc_size, total_free_size,
 482                                    free_buffers, largest_free_size);
 483                 return ERR_PTR(-ENOSPC);
 484         }
 485         if (n == NULL) {
 486                 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
 487                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 488         }
 489
 490         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 491                      "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
 492                       alloc->pid, size, buffer, buffer_size);
 493
 494         has_page_addr = (void __user *)
 495                 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
 496         WARN_ON(n && buffer_size != size);
 497         end_page_addr =
 498                 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
 499         if (end_page_addr > has_page_addr)
 500                 end_page_addr = has_page_addr;
 501         ret = binder_update_page_range(alloc, 1, (void __user *)
 502                 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
 503         if (ret)
 504                 return ERR_PTR(ret);
 505
 506         if (buffer_size != size) {
 507                 struct binder_buffer *new_buffer;
 508
 509                 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 510                 if (!new_buffer) {
 511                         pr_err("%s: %d failed to alloc new buffer struct\n",
 512                                __func__, alloc->pid);
 513                         goto err_alloc_buf_struct_failed;
 514                 }
 515                 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
 516                 list_add(&new_buffer->entry, &buffer->entry);
 517                 new_buffer->free = 1;
 518                 binder_insert_free_buffer(alloc, new_buffer);
 519         }
 520
 521         rb_erase(best_fit, &alloc->free_buffers);
 522         buffer->free = 0;
 523         buffer->allow_user_free = 0;
 524         binder_insert_allocated_buffer_locked(alloc, buffer);
 525         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 526                      "%d: binder_alloc_buf size %zd got %pK\n",
 527                       alloc->pid, size, buffer);
 528         buffer->data_size = data_size;
 529         buffer->offsets_size = offsets_size;
 530         buffer->async_transaction = is_async;
 531         buffer->extra_buffers_size = extra_buffers_size;
 532         buffer->pid = pid;
 533         buffer->oneway_spam_suspect = false;
 534         if (is_async) {
 535                 alloc->free_async_space -= size + sizeof(struct binder_buffer);
 536                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 537                              "%d: binder_alloc_buf size %zd async free %zd\n",
 538                               alloc->pid, size, alloc->free_async_space);
 539                 if (alloc->free_async_space < alloc->buffer_size / 10) {
 540                         /*
 541                          * Start detecting spammers once we have less than 20%
 542                          * of async space left (which is less than 10% of total
 543                          * buffer size).
 544                          */
 545                         buffer->oneway_spam_suspect = debug_low_async_space_locked(alloc, pid);
 546                 } else {
 547                         alloc->oneway_spam_detected = false;
 548                 }
 549         }
 550         return buffer;
 551
 552 err_alloc_buf_struct_failed:
 553         binder_update_page_range(alloc, 0, (void __user *)
 554                                  PAGE_ALIGN((uintptr_t)buffer->user_data),
 555                                  end_page_addr);
 556         return ERR_PTR(-ENOMEM);
 557 }
 558
 559 /**
 560  * binder_alloc_new_buf() - Allocate a new binder buffer
 561  * @alloc:              binder_alloc for this proc
 562  * @data_size:          size of user data buffer
 563  * @offsets_size:       user specified buffer offset
 564  * @extra_buffers_size: size of extra space for meta-data (eg, security context)
 565  * @is_async:           buffer for async transaction
 566  * @pid:                                pid to attribute allocation to (used for debugging)
 567  *
 568  * Allocate a new buffer given the requested sizes. Returns
 569  * the kernel version of the buffer pointer. The size allocated
 570  * is the sum of the three given sizes (each rounded up to
 571  * pointer-sized boundary)
 572  *
 573  * Return:      The allocated buffer or %NULL if error
 574  */
 575 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 576                                            size_t data_size,
 577                                            size_t offsets_size,
 578                                            size_t extra_buffers_size,
 579                                            int is_async,
 580                                            int pid)
 581 {
 582         struct binder_buffer *buffer;
 583
 584         mutex_lock(&alloc->mutex);
 585         buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
 586                                              extra_buffers_size, is_async, pid);
 587         mutex_unlock(&alloc->mutex);
 588         return buffer;
 589 }
 590
 591 static void __user *buffer_start_page(struct binder_buffer *buffer)
 592 {
 593         return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
 594 }
 595
 596 static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
 597 {
 598         return (void __user *)
 599                 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
 600 }
 601
 602 static void binder_delete_free_buffer(struct binder_alloc *alloc,
 603                                       struct binder_buffer *buffer)
 604 {
 605         struct binder_buffer *prev, *next = NULL;
 606         bool to_free = true;
 607
 608         BUG_ON(alloc->buffers.next == &buffer->entry);
 609         prev = binder_buffer_prev(buffer);
 610         BUG_ON(!prev->free);
 611         if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
 612                 to_free = false;
 613                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 614                                    "%d: merge free, buffer %pK share page with %pK\n",
 615                                    alloc->pid, buffer->user_data,
 616                                    prev->user_data);
 617         }
 618
 619         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 620                 next = binder_buffer_next(buffer);
 621                 if (buffer_start_page(next) == buffer_start_page(buffer)) {
 622                         to_free = false;
 623                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 624                                            "%d: merge free, buffer %pK share page with %pK\n",
 625                                            alloc->pid,
 626                                            buffer->user_data,
 627                                            next->user_data);
 628                 }
 629         }
 630
 631         if (PAGE_ALIGNED(buffer->user_data)) {
 632                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 633                                    "%d: merge free, buffer start %pK is page aligned\n",
 634                                    alloc->pid, buffer->user_data);
 635                 to_free = false;
 636         }
 637
 638         if (to_free) {
 639                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 640                                    "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
 641                                    alloc->pid, buffer->user_data,
 642                                    prev->user_data,
 643                                    next ? next->user_data : NULL);
 644                 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
 645                                          buffer_start_page(buffer) + PAGE_SIZE);
 646         }
 647         list_del(&buffer->entry);
 648         kfree(buffer);
 649 }
 650
 651 static void binder_free_buf_locked(struct binder_alloc *alloc,
 652                                    struct binder_buffer *buffer)
 653 {
 654         size_t size, buffer_size;
 655
 656         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 657
 658         size = ALIGN(buffer->data_size, sizeof(void *)) +
 659                 ALIGN(buffer->offsets_size, sizeof(void *)) +
 660                 ALIGN(buffer->extra_buffers_size, sizeof(void *));
 661
 662         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 663                      "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
 664                       alloc->pid, buffer, size, buffer_size);
 665
 666         BUG_ON(buffer->free);
 667         BUG_ON(size > buffer_size);
 668         BUG_ON(buffer->transaction != NULL);
 669         BUG_ON(buffer->user_data < alloc->buffer);
 670         BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
 671
 672         if (buffer->async_transaction) {
 673                 alloc->free_async_space += buffer_size + sizeof(struct binder_buffer);
 674
 675                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 676                              "%d: binder_free_buf size %zd async free %zd\n",
 677                               alloc->pid, size, alloc->free_async_space);
 678         }
 679
 680         binder_update_page_range(alloc, 0,
 681                 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
 682                 (void __user *)(((uintptr_t)
 683                           buffer->user_data + buffer_size) & PAGE_MASK));
 684
 685         rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
 686         buffer->free = 1;
 687         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 688                 struct binder_buffer *next = binder_buffer_next(buffer);
 689
 690                 if (next->free) {
 691                         rb_erase(&next->rb_node, &alloc->free_buffers);
 692                         binder_delete_free_buffer(alloc, next);
 693                 }
 694         }
 695         if (alloc->buffers.next != &buffer->entry) {
 696                 struct binder_buffer *prev = binder_buffer_prev(buffer);
 697
 698                 if (prev->free) {
 699                         binder_delete_free_buffer(alloc, buffer);
 700                         rb_erase(&prev->rb_node, &alloc->free_buffers);
 701                         buffer = prev;
 702                 }
 703         }
 704         binder_insert_free_buffer(alloc, buffer);
 705 }
 706
 707 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
 708                                    struct binder_buffer *buffer);
 709 /**
 710  * binder_alloc_free_buf() - free a binder buffer
 711  * @alloc:      binder_alloc for this proc
 712  * @buffer:     kernel pointer to buffer
 713  *
 714  * Free the buffer allocated via binder_alloc_new_buf()
 715  */
 716 void binder_alloc_free_buf(struct binder_alloc *alloc,
 717                             struct binder_buffer *buffer)
 718 {
 719         /*
 720          * We could eliminate the call to binder_alloc_clear_buf()
 721          * from binder_alloc_deferred_release() by moving this to
 722          * binder_alloc_free_buf_locked(). However, that could
 723          * increase contention for the alloc mutex if clear_on_free
 724          * is used frequently for large buffers. The mutex is not
 725          * needed for correctness here.
 726          */
 727         if (buffer->clear_on_free) {
 728                 binder_alloc_clear_buf(alloc, buffer);
 729                 buffer->clear_on_free = false;
 730         }
 731         mutex_lock(&alloc->mutex);
 732         binder_free_buf_locked(alloc, buffer);
 733         mutex_unlock(&alloc->mutex);
 734 }
 735
 736 /**
 737  * binder_alloc_mmap_handler() - map virtual address space for proc
 738  * @alloc:      alloc structure for this proc
 739  * @vma:        vma passed to mmap()
 740  *
 741  * Called by binder_mmap() to initialize the space specified in
 742  * vma for allocating binder buffers
 743  *
 744  * Return:
 745  *      0 = success
 746  *      -EBUSY = address space already mapped
 747  *      -ENOMEM = failed to map memory to given address space
 748  */
 749 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 750                               struct vm_area_struct *vma)
 751 {
 752         int ret;
 753         const char *failure_string;
 754         struct binder_buffer *buffer;
 755
 756         if (unlikely(vma->vm_mm != alloc->vma_vm_mm)) {
 757                 ret = -EINVAL;
 758                 failure_string = "invalid vma->vm_mm";
 759                 goto err_invalid_mm;
 760         }
 761
 762         mutex_lock(&binder_alloc_mmap_lock);
 763         if (alloc->buffer_size) {
 764                 ret = -EBUSY;
 765                 failure_string = "already mapped";
 766                 goto err_already_mapped;
 767         }
 768         alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
 769                                    SZ_4M);
 770         mutex_unlock(&binder_alloc_mmap_lock);
 771
 772         alloc->buffer = (void __user *)vma->vm_start;
 773
 774         alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
 775                                sizeof(alloc->pages[0]),
 776                                GFP_KERNEL);
 777         if (alloc->pages == NULL) {
 778                 ret = -ENOMEM;
 779                 failure_string = "alloc page array";
 780                 goto err_alloc_pages_failed;
 781         }
 782
 783         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 784         if (!buffer) {
 785                 ret = -ENOMEM;
 786                 failure_string = "alloc buffer struct";
 787                 goto err_alloc_buf_struct_failed;
 788         }
 789
 790         buffer->user_data = alloc->buffer;
 791         list_add(&buffer->entry, &alloc->buffers);
 792         buffer->free = 1;
 793         binder_insert_free_buffer(alloc, buffer);
 794         alloc->free_async_space = alloc->buffer_size / 2;
 795         binder_alloc_set_vma(alloc, vma);
 796
 797         return 0;
 798
 799 err_alloc_buf_struct_failed:
 800         kfree(alloc->pages);
 801         alloc->pages = NULL;
 802 err_alloc_pages_failed:
 803         alloc->buffer = NULL;
 804         mutex_lock(&binder_alloc_mmap_lock);
 805         alloc->buffer_size = 0;
 806 err_already_mapped:
 807         mutex_unlock(&binder_alloc_mmap_lock);
 808 err_invalid_mm:
 809         binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 810                            "%s: %d %lx-%lx %s failed %d\n", __func__,
 811                            alloc->pid, vma->vm_start, vma->vm_end,
 812                            failure_string, ret);
 813         return ret;
 814 }
 815
 816
 817 void binder_alloc_deferred_release(struct binder_alloc *alloc)
 818 {
 819         struct rb_node *n;
 820         int buffers, page_count;
 821         struct binder_buffer *buffer;
 822
 823         buffers = 0;
 824         mutex_lock(&alloc->mutex);
 825         BUG_ON(alloc->vma_addr &&
 826                vma_lookup(alloc->vma_vm_mm, alloc->vma_addr));
 827
 828         while ((n = rb_first(&alloc->allocated_buffers))) {
 829                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 830
 831                 /* Transaction should already have been freed */
 832                 BUG_ON(buffer->transaction);
 833
 834                 if (buffer->clear_on_free) {
 835                         binder_alloc_clear_buf(alloc, buffer);
 836                         buffer->clear_on_free = false;
 837                 }
 838                 binder_free_buf_locked(alloc, buffer);
 839                 buffers++;
 840         }
 841
 842         while (!list_empty(&alloc->buffers)) {
 843                 buffer = list_first_entry(&alloc->buffers,
 844                                           struct binder_buffer, entry);
 845                 WARN_ON(!buffer->free);
 846
 847                 list_del(&buffer->entry);
 848                 WARN_ON_ONCE(!list_empty(&alloc->buffers));
 849                 kfree(buffer);
 850         }
 851
 852         page_count = 0;
 853         if (alloc->pages) {
 854                 int i;
 855
 856                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 857                         void __user *page_addr;
 858                         bool on_lru;
 859
 860                         if (!alloc->pages[i].page_ptr)
 861                                 continue;
 862
 863                         on_lru = list_lru_del(&binder_alloc_lru,
 864                                               &alloc->pages[i].lru);
 865                         page_addr = alloc->buffer + i * PAGE_SIZE;
 866                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 867                                      "%s: %d: page %d at %pK %s\n",
 868                                      __func__, alloc->pid, i, page_addr,
 869                                      on_lru ? "on lru" : "active");
 870                         __free_page(alloc->pages[i].page_ptr);
 871                         page_count++;
 872                 }
 873                 kfree(alloc->pages);
 874         }
 875         mutex_unlock(&alloc->mutex);
 876         if (alloc->vma_vm_mm)
 877                 mmdrop(alloc->vma_vm_mm);
 878
 879         binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
 880                      "%s: %d buffers %d, pages %d\n",
 881                      __func__, alloc->pid, buffers, page_count);
 882 }
 883
 884 static void print_binder_buffer(struct seq_file *m, const char *prefix,
 885                                 struct binder_buffer *buffer)
 886 {
 887         seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
 888                    prefix, buffer->debug_id, buffer->user_data,
 889                    buffer->data_size, buffer->offsets_size,
 890                    buffer->extra_buffers_size,
 891                    buffer->transaction ? "active" : "delivered");
 892 }
 893
 894 /**
 895  * binder_alloc_print_allocated() - print buffer info
 896  * @m:     seq_file for output via seq_printf()
 897  * @alloc: binder_alloc for this proc
 898  *
 899  * Prints information about every buffer associated with
 900  * the binder_alloc state to the given seq_file
 901  */
 902 void binder_alloc_print_allocated(struct seq_file *m,
 903                                   struct binder_alloc *alloc)
 904 {
 905         struct rb_node *n;
 906
 907         mutex_lock(&alloc->mutex);
 908         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 909                 print_binder_buffer(m, "  buffer",
 910                                     rb_entry(n, struct binder_buffer, rb_node));
 911         mutex_unlock(&alloc->mutex);
 912 }
 913
 914 /**
 915  * binder_alloc_print_pages() - print page usage
 916  * @m:     seq_file for output via seq_printf()
 917  * @alloc: binder_alloc for this proc
 918  */
 919 void binder_alloc_print_pages(struct seq_file *m,
 920                               struct binder_alloc *alloc)
 921 {
 922         struct binder_lru_page *page;
 923         int i;
 924         int active = 0;
 925         int lru = 0;
 926         int free = 0;
 927
 928         mutex_lock(&alloc->mutex);
 929         /*
 930          * Make sure the binder_alloc is fully initialized, otherwise we might
 931          * read inconsistent state.
 932          */
 933
 934         mmap_read_lock(alloc->vma_vm_mm);
 935         if (binder_alloc_get_vma(alloc) == NULL) {
 936                 mmap_read_unlock(alloc->vma_vm_mm);
 937                 goto uninitialized;
 938         }
 939
 940         mmap_read_unlock(alloc->vma_vm_mm);
 941         for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 942                 page = &alloc->pages[i];
 943                 if (!page->page_ptr)
 944                         free++;
 945                 else if (list_empty(&page->lru))
 946                         active++;
 947                 else
 948                         lru++;
 949         }
 950
 951 uninitialized:
 952         mutex_unlock(&alloc->mutex);
 953         seq_printf(m, "  pages: %d:%d:%d\n", active, lru, free);
 954         seq_printf(m, "  pages high watermark: %zu\n", alloc->pages_high);
 955 }
 956
 957 /**
 958  * binder_alloc_get_allocated_count() - return count of buffers
 959  * @alloc: binder_alloc for this proc
 960  *
 961  * Return: count of allocated buffers
 962  */
 963 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
 964 {
 965         struct rb_node *n;
 966         int count = 0;
 967
 968         mutex_lock(&alloc->mutex);
 969         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 970                 count++;
 971         mutex_unlock(&alloc->mutex);
 972         return count;
 973 }
 974
 975
 976 /**
 977  * binder_alloc_vma_close() - invalidate address space
 978  * @alloc: binder_alloc for this proc
 979  *
 980  * Called from binder_vma_close() when releasing address space.
 981  * Clears alloc->vma to prevent new incoming transactions from
 982  * allocating more buffers.
 983  */
 984 void binder_alloc_vma_close(struct binder_alloc *alloc)
 985 {
 986         binder_alloc_set_vma(alloc, NULL);
 987 }
 988
 989 /**
 990  * binder_alloc_free_page() - shrinker callback to free pages
 991  * @item:   item to free
 992  * @lock:   lock protecting the item
 993  * @cb_arg: callback argument
 994  *
 995  * Called from list_lru_walk() in binder_shrink_scan() to free
 996  * up pages when the system is under memory pressure.
 997  */
 998 enum lru_status binder_alloc_free_page(struct list_head *item,
 999                                        struct list_lru_one *lru,
1000                                        spinlock_t *lock,
1001                                        void *cb_arg)
1002         __must_hold(lock)
1003 {
1004         struct mm_struct *mm = NULL;
1005         struct binder_lru_page *page = container_of(item,
1006                                                     struct binder_lru_page,
1007                                                     lru);
1008         struct binder_alloc *alloc;
1009         uintptr_t page_addr;
1010         size_t index;
1011         struct vm_area_struct *vma;
1012
1013         alloc = page->alloc;
1014         if (!mutex_trylock(&alloc->mutex))
1015                 goto err_get_alloc_mutex_failed;
1016
1017         if (!page->page_ptr)
1018                 goto err_page_already_freed;
1019
1020         index = page - alloc->pages;
1021         page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
1022
1023         mm = alloc->vma_vm_mm;
1024         if (!mmget_not_zero(mm))
1025                 goto err_mmget;
1026         if (!mmap_read_trylock(mm))
1027                 goto err_mmap_read_lock_failed;
1028         vma = binder_alloc_get_vma(alloc);
1029
1030         list_lru_isolate(lru, item);
1031         spin_unlock(lock);
1032
1033         if (vma) {
1034                 trace_binder_unmap_user_start(alloc, index);
1035
1036                 zap_page_range(vma, page_addr, PAGE_SIZE);
1037
1038                 trace_binder_unmap_user_end(alloc, index);
1039         }
1040         mmap_read_unlock(mm);
1041         mmput_async(mm);
1042
1043         trace_binder_unmap_kernel_start(alloc, index);
1044
1045         __free_page(page->page_ptr);
1046         page->page_ptr = NULL;
1047
1048         trace_binder_unmap_kernel_end(alloc, index);
1049
1050         spin_lock(lock);
1051         mutex_unlock(&alloc->mutex);
1052         return LRU_REMOVED_RETRY;
1053
1054 err_mmap_read_lock_failed:
1055         mmput_async(mm);
1056 err_mmget:
1057 err_page_already_freed:
1058         mutex_unlock(&alloc->mutex);
1059 err_get_alloc_mutex_failed:
1060         return LRU_SKIP;
1061 }
1062
1063 static unsigned long
1064 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
1065 {
1066         unsigned long ret = list_lru_count(&binder_alloc_lru);
1067         return ret;
1068 }
1069
1070 static unsigned long
1071 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1072 {
1073         unsigned long ret;
1074
1075         ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
1076                             NULL, sc->nr_to_scan);
1077         return ret;
1078 }
1079
1080 static struct shrinker binder_shrinker = {
1081         .count_objects = binder_shrink_count,
1082         .scan_objects = binder_shrink_scan,
1083         .seeks = DEFAULT_SEEKS,
1084 };
1085
1086 /**
1087  * binder_alloc_init() - called by binder_open() for per-proc initialization
1088  * @alloc: binder_alloc for this proc
1089  *
1090  * Called from binder_open() to initialize binder_alloc fields for
1091  * new binder proc
1092  */
1093 void binder_alloc_init(struct binder_alloc *alloc)
1094 {
1095         alloc->pid = current->group_leader->pid;
1096         alloc->vma_vm_mm = current->mm;
1097         mmgrab(alloc->vma_vm_mm);
1098         mutex_init(&alloc->mutex);
1099         INIT_LIST_HEAD(&alloc->buffers);
1100 }
1101
1102 int binder_alloc_shrinker_init(void)
1103 {
1104         int ret = list_lru_init(&binder_alloc_lru);
1105
1106         if (ret == 0) {
1107                 ret = register_shrinker(&binder_shrinker);
1108                 if (ret)
1109                         list_lru_destroy(&binder_alloc_lru);
1110         }
1111         return ret;
1112 }
1113
1114 /**
1115  * check_buffer() - verify that buffer/offset is safe to access
1116  * @alloc: binder_alloc for this proc
1117  * @buffer: binder buffer to be accessed
1118  * @offset: offset into @buffer data
1119  * @bytes: bytes to access from offset
1120  *
1121  * Check that the @offset/@bytes are within the size of the given
1122  * @buffer and that the buffer is currently active and not freeable.
1123  * Offsets must also be multiples of sizeof(u32). The kernel is
1124  * allowed to touch the buffer in two cases:
1125  *
1126  * 1) when the buffer is being created:
1127  *     (buffer->free == 0 && buffer->allow_user_free == 0)
1128  * 2) when the buffer is being torn down:
1129  *     (buffer->free == 0 && buffer->transaction == NULL).
1130  *
1131  * Return: true if the buffer is safe to access
1132  */
1133 static inline bool check_buffer(struct binder_alloc *alloc,
1134                                 struct binder_buffer *buffer,
1135                                 binder_size_t offset, size_t bytes)
1136 {
1137         size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1138
1139         return buffer_size >= bytes &&
1140                 offset <= buffer_size - bytes &&
1141                 IS_ALIGNED(offset, sizeof(u32)) &&
1142                 !buffer->free &&
1143                 (!buffer->allow_user_free || !buffer->transaction);
1144 }
1145
1146 /**
1147  * binder_alloc_get_page() - get kernel pointer for given buffer offset
1148  * @alloc: binder_alloc for this proc
1149  * @buffer: binder buffer to be accessed
1150  * @buffer_offset: offset into @buffer data
1151  * @pgoffp: address to copy final page offset to
1152  *
1153  * Lookup the struct page corresponding to the address
1154  * at @buffer_offset into @buffer->user_data. If @pgoffp is not
1155  * NULL, the byte-offset into the page is written there.
1156  *
1157  * The caller is responsible to ensure that the offset points
1158  * to a valid address within the @buffer and that @buffer is
1159  * not freeable by the user. Since it can't be freed, we are
1160  * guaranteed that the corresponding elements of @alloc->pages[]
1161  * cannot change.
1162  *
1163  * Return: struct page
1164  */
1165 static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1166                                           struct binder_buffer *buffer,
1167                                           binder_size_t buffer_offset,
1168                                           pgoff_t *pgoffp)
1169 {
1170         binder_size_t buffer_space_offset = buffer_offset +
1171                 (buffer->user_data - alloc->buffer);
1172         pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
1173         size_t index = buffer_space_offset >> PAGE_SHIFT;
1174         struct binder_lru_page *lru_page;
1175
1176         lru_page = &alloc->pages[index];
1177         *pgoffp = pgoff;
1178         return lru_page->page_ptr;
1179 }
1180
1181 /**
1182  * binder_alloc_clear_buf() - zero out buffer
1183  * @alloc: binder_alloc for this proc
1184  * @buffer: binder buffer to be cleared
1185  *
1186  * memset the given buffer to 0
1187  */
1188 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
1189                                    struct binder_buffer *buffer)
1190 {
1191         size_t bytes = binder_alloc_buffer_size(alloc, buffer);
1192         binder_size_t buffer_offset = 0;
1193
1194         while (bytes) {
1195                 unsigned long size;
1196                 struct page *page;
1197                 pgoff_t pgoff;
1198                 void *kptr;
1199
1200                 page = binder_alloc_get_page(alloc, buffer,
1201                                              buffer_offset, &pgoff);
1202                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1203                 kptr = kmap(page) + pgoff;
1204                 memset(kptr, 0, size);
1205                 kunmap(page);
1206                 bytes -= size;
1207                 buffer_offset += size;
1208         }
1209 }
1210
1211 /**
1212  * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1213  * @alloc: binder_alloc for this proc
1214  * @buffer: binder buffer to be accessed
1215  * @buffer_offset: offset into @buffer data
1216  * @from: userspace pointer to source buffer
1217  * @bytes: bytes to copy
1218  *
1219  * Copy bytes from source userspace to target buffer.
1220  *
1221  * Return: bytes remaining to be copied
1222  */
1223 unsigned long
1224 binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1225                                  struct binder_buffer *buffer,
1226                                  binder_size_t buffer_offset,
1227                                  const void __user *from,
1228                                  size_t bytes)
1229 {
1230         if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1231                 return bytes;
1232
1233         while (bytes) {
1234                 unsigned long size;
1235                 unsigned long ret;
1236                 struct page *page;
1237                 pgoff_t pgoff;
1238                 void *kptr;
1239
1240                 page = binder_alloc_get_page(alloc, buffer,
1241                                              buffer_offset, &pgoff);
1242                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1243                 kptr = kmap(page) + pgoff;
1244                 ret = copy_from_user(kptr, from, size);
1245                 kunmap(page);
1246                 if (ret)
1247                         return bytes - size + ret;
1248                 bytes -= size;
1249                 from += size;
1250                 buffer_offset += size;
1251         }
1252         return 0;
1253 }
1254
1255 static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1256                                        bool to_buffer,
1257                                        struct binder_buffer *buffer,
1258                                        binder_size_t buffer_offset,
1259                                        void *ptr,
1260                                        size_t bytes)
1261 {
1262         /* All copies must be 32-bit aligned and 32-bit size */
1263         if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1264                 return -EINVAL;
1265
1266         while (bytes) {
1267                 unsigned long size;
1268                 struct page *page;
1269                 pgoff_t pgoff;
1270                 void *tmpptr;
1271                 void *base_ptr;
1272
1273                 page = binder_alloc_get_page(alloc, buffer,
1274                                              buffer_offset, &pgoff);
1275                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1276                 base_ptr = kmap_atomic(page);
1277                 tmpptr = base_ptr + pgoff;
1278                 if (to_buffer)
1279                         memcpy(tmpptr, ptr, size);
1280                 else
1281                         memcpy(ptr, tmpptr, size);
1282                 /*
1283                  * kunmap_atomic() takes care of flushing the cache
1284                  * if this device has VIVT cache arch
1285                  */
1286                 kunmap_atomic(base_ptr);
1287                 bytes -= size;
1288                 pgoff = 0;
1289                 ptr = ptr + size;
1290                 buffer_offset += size;
1291         }
1292         return 0;
1293 }
1294
1295 int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1296                                 struct binder_buffer *buffer,
1297                                 binder_size_t buffer_offset,
1298                                 void *src,
1299                                 size_t bytes)
1300 {
1301         return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1302                                            src, bytes);
1303 }
1304
1305 int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1306                                   void *dest,
1307                                   struct binder_buffer *buffer,
1308                                   binder_size_t buffer_offset,
1309                                   size_t bytes)
1310 {
1311         return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
1312                                            dest, bytes);
1313 }
1314