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 = alloc->vma;
 217         }
 218
 219         if (!vma && need_mm) {
 220                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 221                                    "%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
 222                                    alloc->pid);
 223                 goto err_no_vma;
 224         }
 225
 226         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 227                 int ret;
 228                 bool on_lru;
 229                 size_t index;
 230
 231                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 232                 page = &alloc->pages[index];
 233
 234                 if (page->page_ptr) {
 235                         trace_binder_alloc_lru_start(alloc, index);
 236
 237                         on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
 238                         WARN_ON(!on_lru);
 239
 240                         trace_binder_alloc_lru_end(alloc, index);
 241                         continue;
 242                 }
 243
 244                 if (WARN_ON(!vma))
 245                         goto err_page_ptr_cleared;
 246
 247                 trace_binder_alloc_page_start(alloc, index);
 248                 page->page_ptr = alloc_page(GFP_KERNEL |
 249                                             __GFP_HIGHMEM |
 250                                             __GFP_ZERO);
 251                 if (!page->page_ptr) {
 252                         pr_err("%d: binder_alloc_buf failed for page at %pK\n",
 253                                 alloc->pid, page_addr);
 254                         goto err_alloc_page_failed;
 255                 }
 256                 page->alloc = alloc;
 257                 INIT_LIST_HEAD(&page->lru);
 258
 259                 user_page_addr = (uintptr_t)page_addr;
 260                 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
 261                 if (ret) {
 262                         pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
 263                                alloc->pid, user_page_addr);
 264                         goto err_vm_insert_page_failed;
 265                 }
 266
 267                 if (index + 1 > alloc->pages_high)
 268                         alloc->pages_high = index + 1;
 269
 270                 trace_binder_alloc_page_end(alloc, index);
 271         }
 272         if (mm) {
 273                 mmap_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         if (vma)
 317                 alloc->vma_vm_mm = vma->vm_mm;
 318         /*
 319          * If we see alloc->vma is not NULL, buffer data structures set up
 320          * completely. Look at smp_rmb side binder_alloc_get_vma.
 321          * We also want to guarantee new alloc->vma_vm_mm is always visible
 322          * if alloc->vma is set.
 323          */
 324         smp_wmb();
 325         alloc->vma = vma;
 326 }
 327
 328 static inline struct vm_area_struct *binder_alloc_get_vma(
 329                 struct binder_alloc *alloc)
 330 {
 331         struct vm_area_struct *vma = NULL;
 332
 333         if (alloc->vma) {
 334                 /* Look at description in binder_alloc_set_vma */
 335                 smp_rmb();
 336                 vma = alloc->vma;
 337         }
 338         return vma;
 339 }
 340
 341 static bool debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
 342 {
 343         /*
 344          * Find the amount and size of buffers allocated by the current caller;
 345          * The idea is that once we cross the threshold, whoever is responsible
 346          * for the low async space is likely to try to send another async txn,
 347          * and at some point we'll catch them in the act. This is more efficient
 348          * than keeping a map per pid.
 349          */
 350         struct rb_node *n;
 351         struct binder_buffer *buffer;
 352         size_t total_alloc_size = 0;
 353         size_t num_buffers = 0;
 354
 355         for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 356                  n = rb_next(n)) {
 357                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 358                 if (buffer->pid != pid)
 359                         continue;
 360                 if (!buffer->async_transaction)
 361                         continue;
 362                 total_alloc_size += binder_alloc_buffer_size(alloc, buffer)
 363                         + sizeof(struct binder_buffer);
 364                 num_buffers++;
 365         }
 366
 367         /*
 368          * Warn if this pid has more than 50 transactions, or more than 50% of
 369          * async space (which is 25% of total buffer size). Oneway spam is only
 370          * detected when the threshold is exceeded.
 371          */
 372         if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) {
 373                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 374                              "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n",
 375                               alloc->pid, pid, num_buffers, total_alloc_size);
 376                 if (!alloc->oneway_spam_detected) {
 377                         alloc->oneway_spam_detected = true;
 378                         return true;
 379                 }
 380         }
 381         return false;
 382 }
 383
 384 static struct binder_buffer *binder_alloc_new_buf_locked(
 385                                 struct binder_alloc *alloc,
 386                                 size_t data_size,
 387                                 size_t offsets_size,
 388                                 size_t extra_buffers_size,
 389                                 int is_async,
 390                                 int pid)
 391 {
 392         struct rb_node *n = alloc->free_buffers.rb_node;
 393         struct binder_buffer *buffer;
 394         size_t buffer_size;
 395         struct rb_node *best_fit = NULL;
 396         void __user *has_page_addr;
 397         void __user *end_page_addr;
 398         size_t size, data_offsets_size;
 399         int ret;
 400
 401         if (!binder_alloc_get_vma(alloc)) {
 402                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 403                                    "%d: binder_alloc_buf, no vma\n",
 404                                    alloc->pid);
 405                 return ERR_PTR(-ESRCH);
 406         }
 407
 408         data_offsets_size = ALIGN(data_size, sizeof(void *)) +
 409                 ALIGN(offsets_size, sizeof(void *));
 410
 411         if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
 412                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 413                                 "%d: got transaction with invalid size %zd-%zd\n",
 414                                 alloc->pid, data_size, offsets_size);
 415                 return ERR_PTR(-EINVAL);
 416         }
 417         size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
 418         if (size < data_offsets_size || size < extra_buffers_size) {
 419                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 420                                 "%d: got transaction with invalid extra_buffers_size %zd\n",
 421                                 alloc->pid, extra_buffers_size);
 422                 return ERR_PTR(-EINVAL);
 423         }
 424         if (is_async &&
 425             alloc->free_async_space < size + sizeof(struct binder_buffer)) {
 426                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 427                              "%d: binder_alloc_buf size %zd failed, no async space left\n",
 428                               alloc->pid, size);
 429                 return ERR_PTR(-ENOSPC);
 430         }
 431
 432         /* Pad 0-size buffers so they get assigned unique addresses */
 433         size = max(size, sizeof(void *));
 434
 435         while (n) {
 436                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 437                 BUG_ON(!buffer->free);
 438                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 439
 440                 if (size < buffer_size) {
 441                         best_fit = n;
 442                         n = n->rb_left;
 443                 } else if (size > buffer_size)
 444                         n = n->rb_right;
 445                 else {
 446                         best_fit = n;
 447                         break;
 448                 }
 449         }
 450         if (best_fit == NULL) {
 451                 size_t allocated_buffers = 0;
 452                 size_t largest_alloc_size = 0;
 453                 size_t total_alloc_size = 0;
 454                 size_t free_buffers = 0;
 455                 size_t largest_free_size = 0;
 456                 size_t total_free_size = 0;
 457
 458                 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 459                      n = rb_next(n)) {
 460                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 461                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 462                         allocated_buffers++;
 463                         total_alloc_size += buffer_size;
 464                         if (buffer_size > largest_alloc_size)
 465                                 largest_alloc_size = buffer_size;
 466                 }
 467                 for (n = rb_first(&alloc->free_buffers); n != NULL;
 468                      n = rb_next(n)) {
 469                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 470                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 471                         free_buffers++;
 472                         total_free_size += buffer_size;
 473                         if (buffer_size > largest_free_size)
 474                                 largest_free_size = buffer_size;
 475                 }
 476                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 477                                    "%d: binder_alloc_buf size %zd failed, no address space\n",
 478                                    alloc->pid, size);
 479                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 480                                    "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
 481                                    total_alloc_size, allocated_buffers,
 482                                    largest_alloc_size, total_free_size,
 483                                    free_buffers, largest_free_size);
 484                 return ERR_PTR(-ENOSPC);
 485         }
 486         if (n == NULL) {
 487                 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
 488                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 489         }
 490
 491         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 492                      "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
 493                       alloc->pid, size, buffer, buffer_size);
 494
 495         has_page_addr = (void __user *)
 496                 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
 497         WARN_ON(n && buffer_size != size);
 498         end_page_addr =
 499                 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
 500         if (end_page_addr > has_page_addr)
 501                 end_page_addr = has_page_addr;
 502         ret = binder_update_page_range(alloc, 1, (void __user *)
 503                 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
 504         if (ret)
 505                 return ERR_PTR(ret);
 506
 507         if (buffer_size != size) {
 508                 struct binder_buffer *new_buffer;
 509
 510                 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 511                 if (!new_buffer) {
 512                         pr_err("%s: %d failed to alloc new buffer struct\n",
 513                                __func__, alloc->pid);
 514                         goto err_alloc_buf_struct_failed;
 515                 }
 516                 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
 517                 list_add(&new_buffer->entry, &buffer->entry);
 518                 new_buffer->free = 1;
 519                 binder_insert_free_buffer(alloc, new_buffer);
 520         }
 521
 522         rb_erase(best_fit, &alloc->free_buffers);
 523         buffer->free = 0;
 524         buffer->allow_user_free = 0;
 525         binder_insert_allocated_buffer_locked(alloc, buffer);
 526         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 527                      "%d: binder_alloc_buf size %zd got %pK\n",
 528                       alloc->pid, size, buffer);
 529         buffer->data_size = data_size;
 530         buffer->offsets_size = offsets_size;
 531         buffer->async_transaction = is_async;
 532         buffer->extra_buffers_size = extra_buffers_size;
 533         buffer->pid = pid;
 534         buffer->oneway_spam_suspect = false;
 535         if (is_async) {
 536                 alloc->free_async_space -= size + sizeof(struct binder_buffer);
 537                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 538                              "%d: binder_alloc_buf size %zd async free %zd\n",
 539                               alloc->pid, size, alloc->free_async_space);
 540                 if (alloc->free_async_space < alloc->buffer_size / 10) {
 541                         /*
 542                          * Start detecting spammers once we have less than 20%
 543                          * of async space left (which is less than 10% of total
 544                          * buffer size).
 545                          */
 546                         buffer->oneway_spam_suspect = debug_low_async_space_locked(alloc, pid);
 547                 } else {
 548                         alloc->oneway_spam_detected = false;
 549                 }
 550         }
 551         return buffer;
 552
 553 err_alloc_buf_struct_failed:
 554         binder_update_page_range(alloc, 0, (void __user *)
 555                                  PAGE_ALIGN((uintptr_t)buffer->user_data),
 556                                  end_page_addr);
 557         return ERR_PTR(-ENOMEM);
 558 }
 559
 560 /**
 561  * binder_alloc_new_buf() - Allocate a new binder buffer
 562  * @alloc:              binder_alloc for this proc
 563  * @data_size:          size of user data buffer
 564  * @offsets_size:       user specified buffer offset
 565  * @extra_buffers_size: size of extra space for meta-data (eg, security context)
 566  * @is_async:           buffer for async transaction
 567  * @pid:                                pid to attribute allocation to (used for debugging)
 568  *
 569  * Allocate a new buffer given the requested sizes. Returns
 570  * the kernel version of the buffer pointer. The size allocated
 571  * is the sum of the three given sizes (each rounded up to
 572  * pointer-sized boundary)
 573  *
 574  * Return:      The allocated buffer or %NULL if error
 575  */
 576 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 577                                            size_t data_size,
 578                                            size_t offsets_size,
 579                                            size_t extra_buffers_size,
 580                                            int is_async,
 581                                            int pid)
 582 {
 583         struct binder_buffer *buffer;
 584
 585         mutex_lock(&alloc->mutex);
 586         buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
 587                                              extra_buffers_size, is_async, pid);
 588         mutex_unlock(&alloc->mutex);
 589         return buffer;
 590 }
 591
 592 static void __user *buffer_start_page(struct binder_buffer *buffer)
 593 {
 594         return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
 595 }
 596
 597 static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
 598 {
 599         return (void __user *)
 600                 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
 601 }
 602
 603 static void binder_delete_free_buffer(struct binder_alloc *alloc,
 604                                       struct binder_buffer *buffer)
 605 {
 606         struct binder_buffer *prev, *next = NULL;
 607         bool to_free = true;
 608
 609         BUG_ON(alloc->buffers.next == &buffer->entry);
 610         prev = binder_buffer_prev(buffer);
 611         BUG_ON(!prev->free);
 612         if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
 613                 to_free = false;
 614                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 615                                    "%d: merge free, buffer %pK share page with %pK\n",
 616                                    alloc->pid, buffer->user_data,
 617                                    prev->user_data);
 618         }
 619
 620         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 621                 next = binder_buffer_next(buffer);
 622                 if (buffer_start_page(next) == buffer_start_page(buffer)) {
 623                         to_free = false;
 624                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 625                                            "%d: merge free, buffer %pK share page with %pK\n",
 626                                            alloc->pid,
 627                                            buffer->user_data,
 628                                            next->user_data);
 629                 }
 630         }
 631
 632         if (PAGE_ALIGNED(buffer->user_data)) {
 633                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 634                                    "%d: merge free, buffer start %pK is page aligned\n",
 635                                    alloc->pid, buffer->user_data);
 636                 to_free = false;
 637         }
 638
 639         if (to_free) {
 640                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 641                                    "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
 642                                    alloc->pid, buffer->user_data,
 643                                    prev->user_data,
 644                                    next ? next->user_data : NULL);
 645                 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
 646                                          buffer_start_page(buffer) + PAGE_SIZE);
 647         }
 648         list_del(&buffer->entry);
 649         kfree(buffer);
 650 }
 651
 652 static void binder_free_buf_locked(struct binder_alloc *alloc,
 653                                    struct binder_buffer *buffer)
 654 {
 655         size_t size, buffer_size;
 656
 657         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 658
 659         size = ALIGN(buffer->data_size, sizeof(void *)) +
 660                 ALIGN(buffer->offsets_size, sizeof(void *)) +
 661                 ALIGN(buffer->extra_buffers_size, sizeof(void *));
 662
 663         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 664                      "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
 665                       alloc->pid, buffer, size, buffer_size);
 666
 667         BUG_ON(buffer->free);
 668         BUG_ON(size > buffer_size);
 669         BUG_ON(buffer->transaction != NULL);
 670         BUG_ON(buffer->user_data < alloc->buffer);
 671         BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
 672
 673         if (buffer->async_transaction) {
 674                 alloc->free_async_space += size + sizeof(struct binder_buffer);
 675
 676                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 677                              "%d: binder_free_buf size %zd async free %zd\n",
 678                               alloc->pid, size, alloc->free_async_space);
 679         }
 680
 681         binder_update_page_range(alloc, 0,
 682                 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
 683                 (void __user *)(((uintptr_t)
 684                           buffer->user_data + buffer_size) & PAGE_MASK));
 685
 686         rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
 687         buffer->free = 1;
 688         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 689                 struct binder_buffer *next = binder_buffer_next(buffer);
 690
 691                 if (next->free) {
 692                         rb_erase(&next->rb_node, &alloc->free_buffers);
 693                         binder_delete_free_buffer(alloc, next);
 694                 }
 695         }
 696         if (alloc->buffers.next != &buffer->entry) {
 697                 struct binder_buffer *prev = binder_buffer_prev(buffer);
 698
 699                 if (prev->free) {
 700                         binder_delete_free_buffer(alloc, buffer);
 701                         rb_erase(&prev->rb_node, &alloc->free_buffers);
 702                         buffer = prev;
 703                 }
 704         }
 705         binder_insert_free_buffer(alloc, buffer);
 706 }
 707
 708 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
 709                                    struct binder_buffer *buffer);
 710 /**
 711  * binder_alloc_free_buf() - free a binder buffer
 712  * @alloc:      binder_alloc for this proc
 713  * @buffer:     kernel pointer to buffer
 714  *
 715  * Free the buffer allocated via binder_alloc_new_buf()
 716  */
 717 void binder_alloc_free_buf(struct binder_alloc *alloc,
 718                             struct binder_buffer *buffer)
 719 {
 720         /*
 721          * We could eliminate the call to binder_alloc_clear_buf()
 722          * from binder_alloc_deferred_release() by moving this to
 723          * binder_alloc_free_buf_locked(). However, that could
 724          * increase contention for the alloc mutex if clear_on_free
 725          * is used frequently for large buffers. The mutex is not
 726          * needed for correctness here.
 727          */
 728         if (buffer->clear_on_free) {
 729                 binder_alloc_clear_buf(alloc, buffer);
 730                 buffer->clear_on_free = false;
 731         }
 732         mutex_lock(&alloc->mutex);
 733         binder_free_buf_locked(alloc, buffer);
 734         mutex_unlock(&alloc->mutex);
 735 }
 736
 737 /**
 738  * binder_alloc_mmap_handler() - map virtual address space for proc
 739  * @alloc:      alloc structure for this proc
 740  * @vma:        vma passed to mmap()
 741  *
 742  * Called by binder_mmap() to initialize the space specified in
 743  * vma for allocating binder buffers
 744  *
 745  * Return:
 746  *      0 = success
 747  *      -EBUSY = address space already mapped
 748  *      -ENOMEM = failed to map memory to given address space
 749  */
 750 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 751                               struct vm_area_struct *vma)
 752 {
 753         int ret;
 754         const char *failure_string;
 755         struct binder_buffer *buffer;
 756
 757         mutex_lock(&binder_alloc_mmap_lock);
 758         if (alloc->buffer_size) {
 759                 ret = -EBUSY;
 760                 failure_string = "already mapped";
 761                 goto err_already_mapped;
 762         }
 763         alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
 764                                    SZ_4M);
 765         mutex_unlock(&binder_alloc_mmap_lock);
 766
 767         alloc->buffer = (void __user *)vma->vm_start;
 768
 769         alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
 770                                sizeof(alloc->pages[0]),
 771                                GFP_KERNEL);
 772         if (alloc->pages == NULL) {
 773                 ret = -ENOMEM;
 774                 failure_string = "alloc page array";
 775                 goto err_alloc_pages_failed;
 776         }
 777
 778         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 779         if (!buffer) {
 780                 ret = -ENOMEM;
 781                 failure_string = "alloc buffer struct";
 782                 goto err_alloc_buf_struct_failed;
 783         }
 784
 785         buffer->user_data = alloc->buffer;
 786         list_add(&buffer->entry, &alloc->buffers);
 787         buffer->free = 1;
 788         binder_insert_free_buffer(alloc, buffer);
 789         alloc->free_async_space = alloc->buffer_size / 2;
 790         binder_alloc_set_vma(alloc, vma);
 791         mmgrab(alloc->vma_vm_mm);
 792
 793         return 0;
 794
 795 err_alloc_buf_struct_failed:
 796         kfree(alloc->pages);
 797         alloc->pages = NULL;
 798 err_alloc_pages_failed:
 799         alloc->buffer = NULL;
 800         mutex_lock(&binder_alloc_mmap_lock);
 801         alloc->buffer_size = 0;
 802 err_already_mapped:
 803         mutex_unlock(&binder_alloc_mmap_lock);
 804         binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 805                            "%s: %d %lx-%lx %s failed %d\n", __func__,
 806                            alloc->pid, vma->vm_start, vma->vm_end,
 807                            failure_string, ret);
 808         return ret;
 809 }
 810
 811
 812 void binder_alloc_deferred_release(struct binder_alloc *alloc)
 813 {
 814         struct rb_node *n;
 815         int buffers, page_count;
 816         struct binder_buffer *buffer;
 817
 818         buffers = 0;
 819         mutex_lock(&alloc->mutex);
 820         BUG_ON(alloc->vma);
 821
 822         while ((n = rb_first(&alloc->allocated_buffers))) {
 823                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 824
 825                 /* Transaction should already have been freed */
 826                 BUG_ON(buffer->transaction);
 827
 828                 if (buffer->clear_on_free) {
 829                         binder_alloc_clear_buf(alloc, buffer);
 830                         buffer->clear_on_free = false;
 831                 }
 832                 binder_free_buf_locked(alloc, buffer);
 833                 buffers++;
 834         }
 835
 836         while (!list_empty(&alloc->buffers)) {
 837                 buffer = list_first_entry(&alloc->buffers,
 838                                           struct binder_buffer, entry);
 839                 WARN_ON(!buffer->free);
 840
 841                 list_del(&buffer->entry);
 842                 WARN_ON_ONCE(!list_empty(&alloc->buffers));
 843                 kfree(buffer);
 844         }
 845
 846         page_count = 0;
 847         if (alloc->pages) {
 848                 int i;
 849
 850                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 851                         void __user *page_addr;
 852                         bool on_lru;
 853
 854                         if (!alloc->pages[i].page_ptr)
 855                                 continue;
 856
 857                         on_lru = list_lru_del(&binder_alloc_lru,
 858                                               &alloc->pages[i].lru);
 859                         page_addr = alloc->buffer + i * PAGE_SIZE;
 860                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 861                                      "%s: %d: page %d at %pK %s\n",
 862                                      __func__, alloc->pid, i, page_addr,
 863                                      on_lru ? "on lru" : "active");
 864                         __free_page(alloc->pages[i].page_ptr);
 865                         page_count++;
 866                 }
 867                 kfree(alloc->pages);
 868         }
 869         mutex_unlock(&alloc->mutex);
 870         if (alloc->vma_vm_mm)
 871                 mmdrop(alloc->vma_vm_mm);
 872
 873         binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
 874                      "%s: %d buffers %d, pages %d\n",
 875                      __func__, alloc->pid, buffers, page_count);
 876 }
 877
 878 static void print_binder_buffer(struct seq_file *m, const char *prefix,
 879                                 struct binder_buffer *buffer)
 880 {
 881         seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
 882                    prefix, buffer->debug_id, buffer->user_data,
 883                    buffer->data_size, buffer->offsets_size,
 884                    buffer->extra_buffers_size,
 885                    buffer->transaction ? "active" : "delivered");
 886 }
 887
 888 /**
 889  * binder_alloc_print_allocated() - print buffer info
 890  * @m:     seq_file for output via seq_printf()
 891  * @alloc: binder_alloc for this proc
 892  *
 893  * Prints information about every buffer associated with
 894  * the binder_alloc state to the given seq_file
 895  */
 896 void binder_alloc_print_allocated(struct seq_file *m,
 897                                   struct binder_alloc *alloc)
 898 {
 899         struct rb_node *n;
 900
 901         mutex_lock(&alloc->mutex);
 902         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 903                 print_binder_buffer(m, "  buffer",
 904                                     rb_entry(n, struct binder_buffer, rb_node));
 905         mutex_unlock(&alloc->mutex);
 906 }
 907
 908 /**
 909  * binder_alloc_print_pages() - print page usage
 910  * @m:     seq_file for output via seq_printf()
 911  * @alloc: binder_alloc for this proc
 912  */
 913 void binder_alloc_print_pages(struct seq_file *m,
 914                               struct binder_alloc *alloc)
 915 {
 916         struct binder_lru_page *page;
 917         int i;
 918         int active = 0;
 919         int lru = 0;
 920         int free = 0;
 921
 922         mutex_lock(&alloc->mutex);
 923         /*
 924          * Make sure the binder_alloc is fully initialized, otherwise we might
 925          * read inconsistent state.
 926          */
 927         if (binder_alloc_get_vma(alloc) != NULL) {
 928                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 929                         page = &alloc->pages[i];
 930                         if (!page->page_ptr)
 931                                 free++;
 932                         else if (list_empty(&page->lru))
 933                                 active++;
 934                         else
 935                                 lru++;
 936                 }
 937         }
 938         mutex_unlock(&alloc->mutex);
 939         seq_printf(m, "  pages: %d:%d:%d\n", active, lru, free);
 940         seq_printf(m, "  pages high watermark: %zu\n", alloc->pages_high);
 941 }
 942
 943 /**
 944  * binder_alloc_get_allocated_count() - return count of buffers
 945  * @alloc: binder_alloc for this proc
 946  *
 947  * Return: count of allocated buffers
 948  */
 949 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
 950 {
 951         struct rb_node *n;
 952         int count = 0;
 953
 954         mutex_lock(&alloc->mutex);
 955         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 956                 count++;
 957         mutex_unlock(&alloc->mutex);
 958         return count;
 959 }
 960
 961
 962 /**
 963  * binder_alloc_vma_close() - invalidate address space
 964  * @alloc: binder_alloc for this proc
 965  *
 966  * Called from binder_vma_close() when releasing address space.
 967  * Clears alloc->vma to prevent new incoming transactions from
 968  * allocating more buffers.
 969  */
 970 void binder_alloc_vma_close(struct binder_alloc *alloc)
 971 {
 972         binder_alloc_set_vma(alloc, NULL);
 973 }
 974
 975 /**
 976  * binder_alloc_free_page() - shrinker callback to free pages
 977  * @item:   item to free
 978  * @lock:   lock protecting the item
 979  * @cb_arg: callback argument
 980  *
 981  * Called from list_lru_walk() in binder_shrink_scan() to free
 982  * up pages when the system is under memory pressure.
 983  */
 984 enum lru_status binder_alloc_free_page(struct list_head *item,
 985                                        struct list_lru_one *lru,
 986                                        spinlock_t *lock,
 987                                        void *cb_arg)
 988         __must_hold(lock)
 989 {
 990         struct mm_struct *mm = NULL;
 991         struct binder_lru_page *page = container_of(item,
 992                                                     struct binder_lru_page,
 993                                                     lru);
 994         struct binder_alloc *alloc;
 995         uintptr_t page_addr;
 996         size_t index;
 997         struct vm_area_struct *vma;
 998
 999         alloc = page->alloc;
1000         if (!mutex_trylock(&alloc->mutex))
1001                 goto err_get_alloc_mutex_failed;
1002
1003         if (!page->page_ptr)
1004                 goto err_page_already_freed;
1005
1006         index = page - alloc->pages;
1007         page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
1008
1009         mm = alloc->vma_vm_mm;
1010         if (!mmget_not_zero(mm))
1011                 goto err_mmget;
1012         if (!mmap_read_trylock(mm))
1013                 goto err_mmap_read_lock_failed;
1014         vma = binder_alloc_get_vma(alloc);
1015
1016         list_lru_isolate(lru, item);
1017         spin_unlock(lock);
1018
1019         if (vma) {
1020                 trace_binder_unmap_user_start(alloc, index);
1021
1022                 zap_page_range(vma, page_addr, PAGE_SIZE);
1023
1024                 trace_binder_unmap_user_end(alloc, index);
1025         }
1026         mmap_read_unlock(mm);
1027         mmput_async(mm);
1028
1029         trace_binder_unmap_kernel_start(alloc, index);
1030
1031         __free_page(page->page_ptr);
1032         page->page_ptr = NULL;
1033
1034         trace_binder_unmap_kernel_end(alloc, index);
1035
1036         spin_lock(lock);
1037         mutex_unlock(&alloc->mutex);
1038         return LRU_REMOVED_RETRY;
1039
1040 err_mmap_read_lock_failed:
1041         mmput_async(mm);
1042 err_mmget:
1043 err_page_already_freed:
1044         mutex_unlock(&alloc->mutex);
1045 err_get_alloc_mutex_failed:
1046         return LRU_SKIP;
1047 }
1048
1049 static unsigned long
1050 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
1051 {
1052         unsigned long ret = list_lru_count(&binder_alloc_lru);
1053         return ret;
1054 }
1055
1056 static unsigned long
1057 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1058 {
1059         unsigned long ret;
1060
1061         ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
1062                             NULL, sc->nr_to_scan);
1063         return ret;
1064 }
1065
1066 static struct shrinker binder_shrinker = {
1067         .count_objects = binder_shrink_count,
1068         .scan_objects = binder_shrink_scan,
1069         .seeks = DEFAULT_SEEKS,
1070 };
1071
1072 /**
1073  * binder_alloc_init() - called by binder_open() for per-proc initialization
1074  * @alloc: binder_alloc for this proc
1075  *
1076  * Called from binder_open() to initialize binder_alloc fields for
1077  * new binder proc
1078  */
1079 void binder_alloc_init(struct binder_alloc *alloc)
1080 {
1081         alloc->pid = current->group_leader->pid;
1082         mutex_init(&alloc->mutex);
1083         INIT_LIST_HEAD(&alloc->buffers);
1084 }
1085
1086 int binder_alloc_shrinker_init(void)
1087 {
1088         int ret = list_lru_init(&binder_alloc_lru);
1089
1090         if (ret == 0) {
1091                 ret = register_shrinker(&binder_shrinker);
1092                 if (ret)
1093                         list_lru_destroy(&binder_alloc_lru);
1094         }
1095         return ret;
1096 }
1097
1098 /**
1099  * check_buffer() - verify that buffer/offset is safe to access
1100  * @alloc: binder_alloc for this proc
1101  * @buffer: binder buffer to be accessed
1102  * @offset: offset into @buffer data
1103  * @bytes: bytes to access from offset
1104  *
1105  * Check that the @offset/@bytes are within the size of the given
1106  * @buffer and that the buffer is currently active and not freeable.
1107  * Offsets must also be multiples of sizeof(u32). The kernel is
1108  * allowed to touch the buffer in two cases:
1109  *
1110  * 1) when the buffer is being created:
1111  *     (buffer->free == 0 && buffer->allow_user_free == 0)
1112  * 2) when the buffer is being torn down:
1113  *     (buffer->free == 0 && buffer->transaction == NULL).
1114  *
1115  * Return: true if the buffer is safe to access
1116  */
1117 static inline bool check_buffer(struct binder_alloc *alloc,
1118                                 struct binder_buffer *buffer,
1119                                 binder_size_t offset, size_t bytes)
1120 {
1121         size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1122
1123         return buffer_size >= bytes &&
1124                 offset <= buffer_size - bytes &&
1125                 IS_ALIGNED(offset, sizeof(u32)) &&
1126                 !buffer->free &&
1127                 (!buffer->allow_user_free || !buffer->transaction);
1128 }
1129
1130 /**
1131  * binder_alloc_get_page() - get kernel pointer for given buffer offset
1132  * @alloc: binder_alloc for this proc
1133  * @buffer: binder buffer to be accessed
1134  * @buffer_offset: offset into @buffer data
1135  * @pgoffp: address to copy final page offset to
1136  *
1137  * Lookup the struct page corresponding to the address
1138  * at @buffer_offset into @buffer->user_data. If @pgoffp is not
1139  * NULL, the byte-offset into the page is written there.
1140  *
1141  * The caller is responsible to ensure that the offset points
1142  * to a valid address within the @buffer and that @buffer is
1143  * not freeable by the user. Since it can't be freed, we are
1144  * guaranteed that the corresponding elements of @alloc->pages[]
1145  * cannot change.
1146  *
1147  * Return: struct page
1148  */
1149 static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1150                                           struct binder_buffer *buffer,
1151                                           binder_size_t buffer_offset,
1152                                           pgoff_t *pgoffp)
1153 {
1154         binder_size_t buffer_space_offset = buffer_offset +
1155                 (buffer->user_data - alloc->buffer);
1156         pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
1157         size_t index = buffer_space_offset >> PAGE_SHIFT;
1158         struct binder_lru_page *lru_page;
1159
1160         lru_page = &alloc->pages[index];
1161         *pgoffp = pgoff;
1162         return lru_page->page_ptr;
1163 }
1164
1165 /**
1166  * binder_alloc_clear_buf() - zero out buffer
1167  * @alloc: binder_alloc for this proc
1168  * @buffer: binder buffer to be cleared
1169  *
1170  * memset the given buffer to 0
1171  */
1172 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
1173                                    struct binder_buffer *buffer)
1174 {
1175         size_t bytes = binder_alloc_buffer_size(alloc, buffer);
1176         binder_size_t buffer_offset = 0;
1177
1178         while (bytes) {
1179                 unsigned long size;
1180                 struct page *page;
1181                 pgoff_t pgoff;
1182                 void *kptr;
1183
1184                 page = binder_alloc_get_page(alloc, buffer,
1185                                              buffer_offset, &pgoff);
1186                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1187                 kptr = kmap(page) + pgoff;
1188                 memset(kptr, 0, size);
1189                 kunmap(page);
1190                 bytes -= size;
1191                 buffer_offset += size;
1192         }
1193 }
1194
1195 /**
1196  * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1197  * @alloc: binder_alloc for this proc
1198  * @buffer: binder buffer to be accessed
1199  * @buffer_offset: offset into @buffer data
1200  * @from: userspace pointer to source buffer
1201  * @bytes: bytes to copy
1202  *
1203  * Copy bytes from source userspace to target buffer.
1204  *
1205  * Return: bytes remaining to be copied
1206  */
1207 unsigned long
1208 binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1209                                  struct binder_buffer *buffer,
1210                                  binder_size_t buffer_offset,
1211                                  const void __user *from,
1212                                  size_t bytes)
1213 {
1214         if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1215                 return bytes;
1216
1217         while (bytes) {
1218                 unsigned long size;
1219                 unsigned long ret;
1220                 struct page *page;
1221                 pgoff_t pgoff;
1222                 void *kptr;
1223
1224                 page = binder_alloc_get_page(alloc, buffer,
1225                                              buffer_offset, &pgoff);
1226                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1227                 kptr = kmap(page) + pgoff;
1228                 ret = copy_from_user(kptr, from, size);
1229                 kunmap(page);
1230                 if (ret)
1231                         return bytes - size + ret;
1232                 bytes -= size;
1233                 from += size;
1234                 buffer_offset += size;
1235         }
1236         return 0;
1237 }
1238
1239 static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1240                                        bool to_buffer,
1241                                        struct binder_buffer *buffer,
1242                                        binder_size_t buffer_offset,
1243                                        void *ptr,
1244                                        size_t bytes)
1245 {
1246         /* All copies must be 32-bit aligned and 32-bit size */
1247         if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1248                 return -EINVAL;
1249
1250         while (bytes) {
1251                 unsigned long size;
1252                 struct page *page;
1253                 pgoff_t pgoff;
1254                 void *tmpptr;
1255                 void *base_ptr;
1256
1257                 page = binder_alloc_get_page(alloc, buffer,
1258                                              buffer_offset, &pgoff);
1259                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1260                 base_ptr = kmap_atomic(page);
1261                 tmpptr = base_ptr + pgoff;
1262                 if (to_buffer)
1263                         memcpy(tmpptr, ptr, size);
1264                 else
1265                         memcpy(ptr, tmpptr, size);
1266                 /*
1267                  * kunmap_atomic() takes care of flushing the cache
1268                  * if this device has VIVT cache arch
1269                  */
1270                 kunmap_atomic(base_ptr);
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