drivers/android/binder_alloc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* binder_alloc.c
   3  *
   4  * Android IPC Subsystem
   5  *
   6  * Copyright (C) 2007-2017 Google, Inc.
   7  */
   8
   9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11 #include <linux/list.h>
  12 #include <linux/sched/mm.h>
  13 #include <linux/module.h>
  14 #include <linux/rtmutex.h>
  15 #include <linux/rbtree.h>
  16 #include <linux/seq_file.h>
  17 #include <linux/vmalloc.h>
  18 #include <linux/slab.h>
  19 #include <linux/sched.h>
  20 #include <linux/list_lru.h>
  21 #include <linux/ratelimit.h>
  22 #include <asm/cacheflush.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/highmem.h>
  25 #include <linux/sizes.h>
  26 #include "binder_alloc.h"
  27 #include "binder_trace.h"
  28
  29 struct list_lru binder_alloc_lru;
  30
  31 static DEFINE_MUTEX(binder_alloc_mmap_lock);
  32
  33 enum {
  34         BINDER_DEBUG_USER_ERROR             = 1U << 0,
  35         BINDER_DEBUG_OPEN_CLOSE             = 1U << 1,
  36         BINDER_DEBUG_BUFFER_ALLOC           = 1U << 2,
  37         BINDER_DEBUG_BUFFER_ALLOC_ASYNC     = 1U << 3,
  38 };
  39 static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
  40
  41 module_param_named(debug_mask, binder_alloc_debug_mask,
  42                    uint, 0644);
  43
  44 #define binder_alloc_debug(mask, x...) \
  45         do { \
  46                 if (binder_alloc_debug_mask & mask) \
  47                         pr_info_ratelimited(x); \
  48         } while (0)
  49
  50 static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
  51 {
  52         return list_entry(buffer->entry.next, struct binder_buffer, entry);
  53 }
  54
  55 static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
  56 {
  57         return list_entry(buffer->entry.prev, struct binder_buffer, entry);
  58 }
  59
  60 static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
  61                                        struct binder_buffer *buffer)
  62 {
  63         if (list_is_last(&buffer->entry, &alloc->buffers))
  64                 return alloc->buffer + alloc->buffer_size - buffer->user_data;
  65         return binder_buffer_next(buffer)->user_data - buffer->user_data;
  66 }
  67
  68 static void binder_insert_free_buffer(struct binder_alloc *alloc,
  69                                       struct binder_buffer *new_buffer)
  70 {
  71         struct rb_node **p = &alloc->free_buffers.rb_node;
  72         struct rb_node *parent = NULL;
  73         struct binder_buffer *buffer;
  74         size_t buffer_size;
  75         size_t new_buffer_size;
  76
  77         BUG_ON(!new_buffer->free);
  78
  79         new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
  80
  81         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
  82                      "%d: add free buffer, size %zd, at %pK\n",
  83                       alloc->pid, new_buffer_size, new_buffer);
  84
  85         while (*p) {
  86                 parent = *p;
  87                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
  88                 BUG_ON(!buffer->free);
  89
  90                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
  91
  92                 if (new_buffer_size < buffer_size)
  93                         p = &parent->rb_left;
  94                 else
  95                         p = &parent->rb_right;
  96         }
  97         rb_link_node(&new_buffer->rb_node, parent, p);
  98         rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
  99 }
 100
 101 static void binder_insert_allocated_buffer_locked(
 102                 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
 103 {
 104         struct rb_node **p = &alloc->allocated_buffers.rb_node;
 105         struct rb_node *parent = NULL;
 106         struct binder_buffer *buffer;
 107
 108         BUG_ON(new_buffer->free);
 109
 110         while (*p) {
 111                 parent = *p;
 112                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
 113                 BUG_ON(buffer->free);
 114
 115                 if (new_buffer->user_data < buffer->user_data)
 116                         p = &parent->rb_left;
 117                 else if (new_buffer->user_data > buffer->user_data)
 118                         p = &parent->rb_right;
 119                 else
 120                         BUG();
 121         }
 122         rb_link_node(&new_buffer->rb_node, parent, p);
 123         rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
 124 }
 125
 126 static struct binder_buffer *binder_alloc_prepare_to_free_locked(
 127                 struct binder_alloc *alloc,
 128                 uintptr_t user_ptr)
 129 {
 130         struct rb_node *n = alloc->allocated_buffers.rb_node;
 131         struct binder_buffer *buffer;
 132         void __user *uptr;
 133
 134         uptr = (void __user *)user_ptr;
 135
 136         while (n) {
 137                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 138                 BUG_ON(buffer->free);
 139
 140                 if (uptr < buffer->user_data)
 141                         n = n->rb_left;
 142                 else if (uptr > buffer->user_data)
 143                         n = n->rb_right;
 144                 else {
 145                         /*
 146                          * Guard against user threads attempting to
 147                          * free the buffer when in use by kernel or
 148                          * after it's already been freed.
 149                          */
 150                         if (!buffer->allow_user_free)
 151                                 return ERR_PTR(-EPERM);
 152                         buffer->allow_user_free = 0;
 153                         return buffer;
 154                 }
 155         }
 156         return NULL;
 157 }
 158
 159 /**
 160  * binder_alloc_prepare_to_free() - get buffer given user ptr
 161  * @alloc:      binder_alloc for this proc
 162  * @user_ptr:   User pointer to buffer data
 163  *
 164  * Validate userspace pointer to buffer data and return buffer corresponding to
 165  * that user pointer. Search the rb tree for buffer that matches user data
 166  * pointer.
 167  *
 168  * Return:      Pointer to buffer or NULL
 169  */
 170 struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
 171                                                    uintptr_t user_ptr)
 172 {
 173         struct binder_buffer *buffer;
 174
 175         mutex_lock(&alloc->mutex);
 176         buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
 177         mutex_unlock(&alloc->mutex);
 178         return buffer;
 179 }
 180
 181 static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
 182                                     void __user *start, void __user *end)
 183 {
 184         void __user *page_addr;
 185         unsigned long user_page_addr;
 186         struct binder_lru_page *page;
 187         struct vm_area_struct *vma = NULL;
 188         struct mm_struct *mm = NULL;
 189         bool need_mm = false;
 190
 191         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 192                      "%d: %s pages %pK-%pK\n", alloc->pid,
 193                      allocate ? "allocate" : "free", start, end);
 194
 195         if (end <= start)
 196                 return 0;
 197
 198         trace_binder_update_page_range(alloc, allocate, start, end);
 199
 200         if (allocate == 0)
 201                 goto free_range;
 202
 203         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 204                 page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
 205                 if (!page->page_ptr) {
 206                         need_mm = true;
 207                         break;
 208                 }
 209         }
 210
 211         if (need_mm && mmget_not_zero(alloc->mm))
 212                 mm = alloc->mm;
 213
 214         if (mm) {
 215                 mmap_write_lock(mm);
 216                 vma = alloc->vma;
 217         }
 218
 219         if (!vma && need_mm) {
 220                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 221                                    "%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
 222                                    alloc->pid);
 223                 goto err_no_vma;
 224         }
 225
 226         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 227                 int ret;
 228                 bool on_lru;
 229                 size_t index;
 230
 231                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 232                 page = &alloc->pages[index];
 233
 234                 if (page->page_ptr) {
 235                         trace_binder_alloc_lru_start(alloc, index);
 236
 237                         on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
 238                         WARN_ON(!on_lru);
 239
 240                         trace_binder_alloc_lru_end(alloc, index);
 241                         continue;
 242                 }
 243
 244                 if (WARN_ON(!vma))
 245                         goto err_page_ptr_cleared;
 246
 247                 trace_binder_alloc_page_start(alloc, index);
 248                 page->page_ptr = alloc_page(GFP_KERNEL |
 249                                             __GFP_HIGHMEM |
 250                                             __GFP_ZERO);
 251                 if (!page->page_ptr) {
 252                         pr_err("%d: binder_alloc_buf failed for page at %pK\n",
 253                                 alloc->pid, page_addr);
 254                         goto err_alloc_page_failed;
 255                 }
 256                 page->alloc = alloc;
 257                 INIT_LIST_HEAD(&page->lru);
 258
 259                 user_page_addr = (uintptr_t)page_addr;
 260                 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
 261                 if (ret) {
 262                         pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
 263                                alloc->pid, user_page_addr);
 264                         goto err_vm_insert_page_failed;
 265                 }
 266
 267                 if (index + 1 > alloc->pages_high)
 268                         alloc->pages_high = index + 1;
 269
 270                 trace_binder_alloc_page_end(alloc, index);
 271         }
 272         if (mm) {
 273                 mmap_write_unlock(mm);
 274                 mmput(mm);
 275         }
 276         return 0;
 277
 278 free_range:
 279         for (page_addr = end - PAGE_SIZE; 1; page_addr -= PAGE_SIZE) {
 280                 bool ret;
 281                 size_t index;
 282
 283                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 284                 page = &alloc->pages[index];
 285
 286                 trace_binder_free_lru_start(alloc, index);
 287
 288                 ret = list_lru_add(&binder_alloc_lru, &page->lru);
 289                 WARN_ON(!ret);
 290
 291                 trace_binder_free_lru_end(alloc, index);
 292                 if (page_addr == start)
 293                         break;
 294                 continue;
 295
 296 err_vm_insert_page_failed:
 297                 __free_page(page->page_ptr);
 298                 page->page_ptr = NULL;
 299 err_alloc_page_failed:
 300 err_page_ptr_cleared:
 301                 if (page_addr == start)
 302                         break;
 303         }
 304 err_no_vma:
 305         if (mm) {
 306                 mmap_write_unlock(mm);
 307                 mmput(mm);
 308         }
 309         return vma ? -ENOMEM : -ESRCH;
 310 }
 311
 312 static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
 313                 struct vm_area_struct *vma)
 314 {
 315         /* pairs with smp_load_acquire in binder_alloc_get_vma() */
 316         smp_store_release(&alloc->vma, vma);
 317 }
 318
 319 static inline struct vm_area_struct *binder_alloc_get_vma(
 320                 struct binder_alloc *alloc)
 321 {
 322         /* pairs with smp_store_release in binder_alloc_set_vma() */
 323         return smp_load_acquire(&alloc->vma);
 324 }
 325
 326 static bool debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
 327 {
 328         /*
 329          * Find the amount and size of buffers allocated by the current caller;
 330          * The idea is that once we cross the threshold, whoever is responsible
 331          * for the low async space is likely to try to send another async txn,
 332          * and at some point we'll catch them in the act. This is more efficient
 333          * than keeping a map per pid.
 334          */
 335         struct rb_node *n;
 336         struct binder_buffer *buffer;
 337         size_t total_alloc_size = 0;
 338         size_t num_buffers = 0;
 339
 340         for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 341                  n = rb_next(n)) {
 342                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 343                 if (buffer->pid != pid)
 344                         continue;
 345                 if (!buffer->async_transaction)
 346                         continue;
 347                 total_alloc_size += binder_alloc_buffer_size(alloc, buffer)
 348                         + sizeof(struct binder_buffer);
 349                 num_buffers++;
 350         }
 351
 352         /*
 353          * Warn if this pid has more than 50 transactions, or more than 50% of
 354          * async space (which is 25% of total buffer size). Oneway spam is only
 355          * detected when the threshold is exceeded.
 356          */
 357         if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) {
 358                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 359                              "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n",
 360                               alloc->pid, pid, num_buffers, total_alloc_size);
 361                 if (!alloc->oneway_spam_detected) {
 362                         alloc->oneway_spam_detected = true;
 363                         return true;
 364                 }
 365         }
 366         return false;
 367 }
 368
 369 static struct binder_buffer *binder_alloc_new_buf_locked(
 370                                 struct binder_alloc *alloc,
 371                                 size_t data_size,
 372                                 size_t offsets_size,
 373                                 size_t extra_buffers_size,
 374                                 int is_async,
 375                                 int pid)
 376 {
 377         struct rb_node *n = alloc->free_buffers.rb_node;
 378         struct binder_buffer *buffer;
 379         size_t buffer_size;
 380         struct rb_node *best_fit = NULL;
 381         void __user *has_page_addr;
 382         void __user *end_page_addr;
 383         size_t size, data_offsets_size;
 384         int ret;
 385
 386         /* Check binder_alloc is fully initialized */
 387         if (!binder_alloc_get_vma(alloc)) {
 388                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 389                                    "%d: binder_alloc_buf, no vma\n",
 390                                    alloc->pid);
 391                 return ERR_PTR(-ESRCH);
 392         }
 393
 394         data_offsets_size = ALIGN(data_size, sizeof(void *)) +
 395                 ALIGN(offsets_size, sizeof(void *));
 396
 397         if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
 398                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 399                                 "%d: got transaction with invalid size %zd-%zd\n",
 400                                 alloc->pid, data_size, offsets_size);
 401                 return ERR_PTR(-EINVAL);
 402         }
 403         size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
 404         if (size < data_offsets_size || size < extra_buffers_size) {
 405                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 406                                 "%d: got transaction with invalid extra_buffers_size %zd\n",
 407                                 alloc->pid, extra_buffers_size);
 408                 return ERR_PTR(-EINVAL);
 409         }
 410
 411         /* Pad 0-size buffers so they get assigned unique addresses */
 412         size = max(size, sizeof(void *));
 413
 414         if (is_async &&
 415             alloc->free_async_space < size + sizeof(struct binder_buffer)) {
 416                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 417                              "%d: binder_alloc_buf size %zd failed, no async space left\n",
 418                               alloc->pid, size);
 419                 return ERR_PTR(-ENOSPC);
 420         }
 421
 422         while (n) {
 423                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 424                 BUG_ON(!buffer->free);
 425                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 426
 427                 if (size < buffer_size) {
 428                         best_fit = n;
 429                         n = n->rb_left;
 430                 } else if (size > buffer_size)
 431                         n = n->rb_right;
 432                 else {
 433                         best_fit = n;
 434                         break;
 435                 }
 436         }
 437         if (best_fit == NULL) {
 438                 size_t allocated_buffers = 0;
 439                 size_t largest_alloc_size = 0;
 440                 size_t total_alloc_size = 0;
 441                 size_t free_buffers = 0;
 442                 size_t largest_free_size = 0;
 443                 size_t total_free_size = 0;
 444
 445                 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 446                      n = rb_next(n)) {
 447                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 448                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 449                         allocated_buffers++;
 450                         total_alloc_size += buffer_size;
 451                         if (buffer_size > largest_alloc_size)
 452                                 largest_alloc_size = buffer_size;
 453                 }
 454                 for (n = rb_first(&alloc->free_buffers); n != NULL;
 455                      n = rb_next(n)) {
 456                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 457                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 458                         free_buffers++;
 459                         total_free_size += buffer_size;
 460                         if (buffer_size > largest_free_size)
 461                                 largest_free_size = buffer_size;
 462                 }
 463                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 464                                    "%d: binder_alloc_buf size %zd failed, no address space\n",
 465                                    alloc->pid, size);
 466                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 467                                    "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
 468                                    total_alloc_size, allocated_buffers,
 469                                    largest_alloc_size, total_free_size,
 470                                    free_buffers, largest_free_size);
 471                 return ERR_PTR(-ENOSPC);
 472         }
 473         if (n == NULL) {
 474                 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
 475                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 476         }
 477
 478         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 479                      "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
 480                       alloc->pid, size, buffer, buffer_size);
 481
 482         has_page_addr = (void __user *)
 483                 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
 484         WARN_ON(n && buffer_size != size);
 485         end_page_addr =
 486                 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
 487         if (end_page_addr > has_page_addr)
 488                 end_page_addr = has_page_addr;
 489         ret = binder_update_page_range(alloc, 1, (void __user *)
 490                 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
 491         if (ret)
 492                 return ERR_PTR(ret);
 493
 494         if (buffer_size != size) {
 495                 struct binder_buffer *new_buffer;
 496
 497                 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 498                 if (!new_buffer) {
 499                         pr_err("%s: %d failed to alloc new buffer struct\n",
 500                                __func__, alloc->pid);
 501                         goto err_alloc_buf_struct_failed;
 502                 }
 503                 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
 504                 list_add(&new_buffer->entry, &buffer->entry);
 505                 new_buffer->free = 1;
 506                 binder_insert_free_buffer(alloc, new_buffer);
 507         }
 508
 509         rb_erase(best_fit, &alloc->free_buffers);
 510         buffer->free = 0;
 511         buffer->allow_user_free = 0;
 512         binder_insert_allocated_buffer_locked(alloc, buffer);
 513         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 514                      "%d: binder_alloc_buf size %zd got %pK\n",
 515                       alloc->pid, size, buffer);
 516         buffer->data_size = data_size;
 517         buffer->offsets_size = offsets_size;
 518         buffer->async_transaction = is_async;
 519         buffer->extra_buffers_size = extra_buffers_size;
 520         buffer->pid = pid;
 521         buffer->oneway_spam_suspect = false;
 522         if (is_async) {
 523                 alloc->free_async_space -= size + sizeof(struct binder_buffer);
 524                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 525                              "%d: binder_alloc_buf size %zd async free %zd\n",
 526                               alloc->pid, size, alloc->free_async_space);
 527                 if (alloc->free_async_space < alloc->buffer_size / 10) {
 528                         /*
 529                          * Start detecting spammers once we have less than 20%
 530                          * of async space left (which is less than 10% of total
 531                          * buffer size).
 532                          */
 533                         buffer->oneway_spam_suspect = debug_low_async_space_locked(alloc, pid);
 534                 } else {
 535                         alloc->oneway_spam_detected = false;
 536                 }
 537         }
 538         return buffer;
 539
 540 err_alloc_buf_struct_failed:
 541         binder_update_page_range(alloc, 0, (void __user *)
 542                                  PAGE_ALIGN((uintptr_t)buffer->user_data),
 543                                  end_page_addr);
 544         return ERR_PTR(-ENOMEM);
 545 }
 546
 547 /**
 548  * binder_alloc_new_buf() - Allocate a new binder buffer
 549  * @alloc:              binder_alloc for this proc
 550  * @data_size:          size of user data buffer
 551  * @offsets_size:       user specified buffer offset
 552  * @extra_buffers_size: size of extra space for meta-data (eg, security context)
 553  * @is_async:           buffer for async transaction
 554  * @pid:                                pid to attribute allocation to (used for debugging)
 555  *
 556  * Allocate a new buffer given the requested sizes. Returns
 557  * the kernel version of the buffer pointer. The size allocated
 558  * is the sum of the three given sizes (each rounded up to
 559  * pointer-sized boundary)
 560  *
 561  * Return:      The allocated buffer or %ERR_PTR(-errno) if error
 562  */
 563 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 564                                            size_t data_size,
 565                                            size_t offsets_size,
 566                                            size_t extra_buffers_size,
 567                                            int is_async,
 568                                            int pid)
 569 {
 570         struct binder_buffer *buffer;
 571
 572         mutex_lock(&alloc->mutex);
 573         buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
 574                                              extra_buffers_size, is_async, pid);
 575         mutex_unlock(&alloc->mutex);
 576         return buffer;
 577 }
 578
 579 static void __user *buffer_start_page(struct binder_buffer *buffer)
 580 {
 581         return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
 582 }
 583
 584 static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
 585 {
 586         return (void __user *)
 587                 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
 588 }
 589
 590 static void binder_delete_free_buffer(struct binder_alloc *alloc,
 591                                       struct binder_buffer *buffer)
 592 {
 593         struct binder_buffer *prev, *next = NULL;
 594         bool to_free = true;
 595
 596         BUG_ON(alloc->buffers.next == &buffer->entry);
 597         prev = binder_buffer_prev(buffer);
 598         BUG_ON(!prev->free);
 599         if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
 600                 to_free = false;
 601                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 602                                    "%d: merge free, buffer %pK share page with %pK\n",
 603                                    alloc->pid, buffer->user_data,
 604                                    prev->user_data);
 605         }
 606
 607         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 608                 next = binder_buffer_next(buffer);
 609                 if (buffer_start_page(next) == buffer_start_page(buffer)) {
 610                         to_free = false;
 611                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 612                                            "%d: merge free, buffer %pK share page with %pK\n",
 613                                            alloc->pid,
 614                                            buffer->user_data,
 615                                            next->user_data);
 616                 }
 617         }
 618
 619         if (PAGE_ALIGNED(buffer->user_data)) {
 620                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 621                                    "%d: merge free, buffer start %pK is page aligned\n",
 622                                    alloc->pid, buffer->user_data);
 623                 to_free = false;
 624         }
 625
 626         if (to_free) {
 627                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 628                                    "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
 629                                    alloc->pid, buffer->user_data,
 630                                    prev->user_data,
 631                                    next ? next->user_data : NULL);
 632                 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
 633                                          buffer_start_page(buffer) + PAGE_SIZE);
 634         }
 635         list_del(&buffer->entry);
 636         kfree(buffer);
 637 }
 638
 639 static void binder_free_buf_locked(struct binder_alloc *alloc,
 640                                    struct binder_buffer *buffer)
 641 {
 642         size_t size, buffer_size;
 643
 644         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 645
 646         size = ALIGN(buffer->data_size, sizeof(void *)) +
 647                 ALIGN(buffer->offsets_size, sizeof(void *)) +
 648                 ALIGN(buffer->extra_buffers_size, sizeof(void *));
 649
 650         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 651                      "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
 652                       alloc->pid, buffer, size, buffer_size);
 653
 654         BUG_ON(buffer->free);
 655         BUG_ON(size > buffer_size);
 656         BUG_ON(buffer->transaction != NULL);
 657         BUG_ON(buffer->user_data < alloc->buffer);
 658         BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
 659
 660         if (buffer->async_transaction) {
 661                 alloc->free_async_space += buffer_size + sizeof(struct binder_buffer);
 662
 663                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 664                              "%d: binder_free_buf size %zd async free %zd\n",
 665                               alloc->pid, size, alloc->free_async_space);
 666         }
 667
 668         binder_update_page_range(alloc, 0,
 669                 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
 670                 (void __user *)(((uintptr_t)
 671                           buffer->user_data + buffer_size) & PAGE_MASK));
 672
 673         rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
 674         buffer->free = 1;
 675         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 676                 struct binder_buffer *next = binder_buffer_next(buffer);
 677
 678                 if (next->free) {
 679                         rb_erase(&next->rb_node, &alloc->free_buffers);
 680                         binder_delete_free_buffer(alloc, next);
 681                 }
 682         }
 683         if (alloc->buffers.next != &buffer->entry) {
 684                 struct binder_buffer *prev = binder_buffer_prev(buffer);
 685
 686                 if (prev->free) {
 687                         binder_delete_free_buffer(alloc, buffer);
 688                         rb_erase(&prev->rb_node, &alloc->free_buffers);
 689                         buffer = prev;
 690                 }
 691         }
 692         binder_insert_free_buffer(alloc, buffer);
 693 }
 694
 695 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
 696                                    struct binder_buffer *buffer);
 697 /**
 698  * binder_alloc_free_buf() - free a binder buffer
 699  * @alloc:      binder_alloc for this proc
 700  * @buffer:     kernel pointer to buffer
 701  *
 702  * Free the buffer allocated via binder_alloc_new_buf()
 703  */
 704 void binder_alloc_free_buf(struct binder_alloc *alloc,
 705                             struct binder_buffer *buffer)
 706 {
 707         /*
 708          * We could eliminate the call to binder_alloc_clear_buf()
 709          * from binder_alloc_deferred_release() by moving this to
 710          * binder_free_buf_locked(). However, that could
 711          * increase contention for the alloc mutex if clear_on_free
 712          * is used frequently for large buffers. The mutex is not
 713          * needed for correctness here.
 714          */
 715         if (buffer->clear_on_free) {
 716                 binder_alloc_clear_buf(alloc, buffer);
 717                 buffer->clear_on_free = false;
 718         }
 719         mutex_lock(&alloc->mutex);
 720         binder_free_buf_locked(alloc, buffer);
 721         mutex_unlock(&alloc->mutex);
 722 }
 723
 724 /**
 725  * binder_alloc_mmap_handler() - map virtual address space for proc
 726  * @alloc:      alloc structure for this proc
 727  * @vma:        vma passed to mmap()
 728  *
 729  * Called by binder_mmap() to initialize the space specified in
 730  * vma for allocating binder buffers
 731  *
 732  * Return:
 733  *      0 = success
 734  *      -EBUSY = address space already mapped
 735  *      -ENOMEM = failed to map memory to given address space
 736  */
 737 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 738                               struct vm_area_struct *vma)
 739 {
 740         int ret;
 741         const char *failure_string;
 742         struct binder_buffer *buffer;
 743
 744         if (unlikely(vma->vm_mm != alloc->mm)) {
 745                 ret = -EINVAL;
 746                 failure_string = "invalid vma->vm_mm";
 747                 goto err_invalid_mm;
 748         }
 749
 750         mutex_lock(&binder_alloc_mmap_lock);
 751         if (alloc->buffer_size) {
 752                 ret = -EBUSY;
 753                 failure_string = "already mapped";
 754                 goto err_already_mapped;
 755         }
 756         alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
 757                                    SZ_4M);
 758         mutex_unlock(&binder_alloc_mmap_lock);
 759
 760         alloc->buffer = (void __user *)vma->vm_start;
 761
 762         alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
 763                                sizeof(alloc->pages[0]),
 764                                GFP_KERNEL);
 765         if (alloc->pages == NULL) {
 766                 ret = -ENOMEM;
 767                 failure_string = "alloc page array";
 768                 goto err_alloc_pages_failed;
 769         }
 770
 771         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 772         if (!buffer) {
 773                 ret = -ENOMEM;
 774                 failure_string = "alloc buffer struct";
 775                 goto err_alloc_buf_struct_failed;
 776         }
 777
 778         buffer->user_data = alloc->buffer;
 779         list_add(&buffer->entry, &alloc->buffers);
 780         buffer->free = 1;
 781         binder_insert_free_buffer(alloc, buffer);
 782         alloc->free_async_space = alloc->buffer_size / 2;
 783
 784         /* Signal binder_alloc is fully initialized */
 785         binder_alloc_set_vma(alloc, vma);
 786
 787         return 0;
 788
 789 err_alloc_buf_struct_failed:
 790         kfree(alloc->pages);
 791         alloc->pages = NULL;
 792 err_alloc_pages_failed:
 793         alloc->buffer = NULL;
 794         mutex_lock(&binder_alloc_mmap_lock);
 795         alloc->buffer_size = 0;
 796 err_already_mapped:
 797         mutex_unlock(&binder_alloc_mmap_lock);
 798 err_invalid_mm:
 799         binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 800                            "%s: %d %lx-%lx %s failed %d\n", __func__,
 801                            alloc->pid, vma->vm_start, vma->vm_end,
 802                            failure_string, ret);
 803         return ret;
 804 }
 805
 806
 807 void binder_alloc_deferred_release(struct binder_alloc *alloc)
 808 {
 809         struct rb_node *n;
 810         int buffers, page_count;
 811         struct binder_buffer *buffer;
 812
 813         buffers = 0;
 814         mutex_lock(&alloc->mutex);
 815         BUG_ON(alloc->vma);
 816
 817         while ((n = rb_first(&alloc->allocated_buffers))) {
 818                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 819
 820                 /* Transaction should already have been freed */
 821                 BUG_ON(buffer->transaction);
 822
 823                 if (buffer->clear_on_free) {
 824                         binder_alloc_clear_buf(alloc, buffer);
 825                         buffer->clear_on_free = false;
 826                 }
 827                 binder_free_buf_locked(alloc, buffer);
 828                 buffers++;
 829         }
 830
 831         while (!list_empty(&alloc->buffers)) {
 832                 buffer = list_first_entry(&alloc->buffers,
 833                                           struct binder_buffer, entry);
 834                 WARN_ON(!buffer->free);
 835
 836                 list_del(&buffer->entry);
 837                 WARN_ON_ONCE(!list_empty(&alloc->buffers));
 838                 kfree(buffer);
 839         }
 840
 841         page_count = 0;
 842         if (alloc->pages) {
 843                 int i;
 844
 845                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 846                         void __user *page_addr;
 847                         bool on_lru;
 848
 849                         if (!alloc->pages[i].page_ptr)
 850                                 continue;
 851
 852                         on_lru = list_lru_del(&binder_alloc_lru,
 853                                               &alloc->pages[i].lru);
 854                         page_addr = alloc->buffer + i * PAGE_SIZE;
 855                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 856                                      "%s: %d: page %d at %pK %s\n",
 857                                      __func__, alloc->pid, i, page_addr,
 858                                      on_lru ? "on lru" : "active");
 859                         __free_page(alloc->pages[i].page_ptr);
 860                         page_count++;
 861                 }
 862                 kfree(alloc->pages);
 863         }
 864         mutex_unlock(&alloc->mutex);
 865         if (alloc->mm)
 866                 mmdrop(alloc->mm);
 867
 868         binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
 869                      "%s: %d buffers %d, pages %d\n",
 870                      __func__, alloc->pid, buffers, page_count);
 871 }
 872
 873 static void print_binder_buffer(struct seq_file *m, const char *prefix,
 874                                 struct binder_buffer *buffer)
 875 {
 876         seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
 877                    prefix, buffer->debug_id, buffer->user_data,
 878                    buffer->data_size, buffer->offsets_size,
 879                    buffer->extra_buffers_size,
 880                    buffer->transaction ? "active" : "delivered");
 881 }
 882
 883 /**
 884  * binder_alloc_print_allocated() - print buffer info
 885  * @m:     seq_file for output via seq_printf()
 886  * @alloc: binder_alloc for this proc
 887  *
 888  * Prints information about every buffer associated with
 889  * the binder_alloc state to the given seq_file
 890  */
 891 void binder_alloc_print_allocated(struct seq_file *m,
 892                                   struct binder_alloc *alloc)
 893 {
 894         struct rb_node *n;
 895
 896         mutex_lock(&alloc->mutex);
 897         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 898                 print_binder_buffer(m, "  buffer",
 899                                     rb_entry(n, struct binder_buffer, rb_node));
 900         mutex_unlock(&alloc->mutex);
 901 }
 902
 903 /**
 904  * binder_alloc_print_pages() - print page usage
 905  * @m:     seq_file for output via seq_printf()
 906  * @alloc: binder_alloc for this proc
 907  */
 908 void binder_alloc_print_pages(struct seq_file *m,
 909                               struct binder_alloc *alloc)
 910 {
 911         struct binder_lru_page *page;
 912         int i;
 913         int active = 0;
 914         int lru = 0;
 915         int free = 0;
 916
 917         mutex_lock(&alloc->mutex);
 918         /*
 919          * Make sure the binder_alloc is fully initialized, otherwise we might
 920          * read inconsistent state.
 921          */
 922         if (binder_alloc_get_vma(alloc) != NULL) {
 923                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 924                         page = &alloc->pages[i];
 925                         if (!page->page_ptr)
 926                                 free++;
 927                         else if (list_empty(&page->lru))
 928                                 active++;
 929                         else
 930                                 lru++;
 931                 }
 932         }
 933         mutex_unlock(&alloc->mutex);
 934         seq_printf(m, "  pages: %d:%d:%d\n", active, lru, free);
 935         seq_printf(m, "  pages high watermark: %zu\n", alloc->pages_high);
 936 }
 937
 938 /**
 939  * binder_alloc_get_allocated_count() - return count of buffers
 940  * @alloc: binder_alloc for this proc
 941  *
 942  * Return: count of allocated buffers
 943  */
 944 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
 945 {
 946         struct rb_node *n;
 947         int count = 0;
 948
 949         mutex_lock(&alloc->mutex);
 950         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 951                 count++;
 952         mutex_unlock(&alloc->mutex);
 953         return count;
 954 }
 955
 956
 957 /**
 958  * binder_alloc_vma_close() - invalidate address space
 959  * @alloc: binder_alloc for this proc
 960  *
 961  * Called from binder_vma_close() when releasing address space.
 962  * Clears alloc->vma to prevent new incoming transactions from
 963  * allocating more buffers.
 964  */
 965 void binder_alloc_vma_close(struct binder_alloc *alloc)
 966 {
 967         binder_alloc_set_vma(alloc, NULL);
 968 }
 969
 970 /**
 971  * binder_alloc_free_page() - shrinker callback to free pages
 972  * @item:   item to free
 973  * @lock:   lock protecting the item
 974  * @cb_arg: callback argument
 975  *
 976  * Called from list_lru_walk() in binder_shrink_scan() to free
 977  * up pages when the system is under memory pressure.
 978  */
 979 enum lru_status binder_alloc_free_page(struct list_head *item,
 980                                        struct list_lru_one *lru,
 981                                        spinlock_t *lock,
 982                                        void *cb_arg)
 983         __must_hold(lock)
 984 {
 985         struct mm_struct *mm = NULL;
 986         struct binder_lru_page *page = container_of(item,
 987                                                     struct binder_lru_page,
 988                                                     lru);
 989         struct binder_alloc *alloc;
 990         uintptr_t page_addr;
 991         size_t index;
 992         struct vm_area_struct *vma;
 993
 994         alloc = page->alloc;
 995         if (!mutex_trylock(&alloc->mutex))
 996                 goto err_get_alloc_mutex_failed;
 997
 998         if (!page->page_ptr)
 999                 goto err_page_already_freed;
1000
1001         index = page - alloc->pages;
1002         page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
1003
1004         mm = alloc->mm;
1005         if (!mmget_not_zero(mm))
1006                 goto err_mmget;
1007         if (!mmap_read_trylock(mm))
1008                 goto err_mmap_read_lock_failed;
1009         vma = vma_lookup(mm, page_addr);
1010         if (vma && vma != binder_alloc_get_vma(alloc))
1011                 goto err_invalid_vma;
1012
1013         list_lru_isolate(lru, item);
1014         spin_unlock(lock);
1015
1016         if (vma) {
1017                 trace_binder_unmap_user_start(alloc, index);
1018
1019                 zap_page_range_single(vma, page_addr, PAGE_SIZE, NULL);
1020
1021                 trace_binder_unmap_user_end(alloc, index);
1022         }
1023         mmap_read_unlock(mm);
1024         mmput_async(mm);
1025
1026         trace_binder_unmap_kernel_start(alloc, index);
1027
1028         __free_page(page->page_ptr);
1029         page->page_ptr = NULL;
1030
1031         trace_binder_unmap_kernel_end(alloc, index);
1032
1033         spin_lock(lock);
1034         mutex_unlock(&alloc->mutex);
1035         return LRU_REMOVED_RETRY;
1036
1037 err_invalid_vma:
1038         mmap_read_unlock(mm);
1039 err_mmap_read_lock_failed:
1040         mmput_async(mm);
1041 err_mmget:
1042 err_page_already_freed:
1043         mutex_unlock(&alloc->mutex);
1044 err_get_alloc_mutex_failed:
1045         return LRU_SKIP;
1046 }
1047
1048 static unsigned long
1049 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
1050 {
1051         return list_lru_count(&binder_alloc_lru);
1052 }
1053
1054 static unsigned long
1055 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1056 {
1057         return list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
1058                             NULL, sc->nr_to_scan);
1059 }
1060
1061 static struct shrinker binder_shrinker = {
1062         .count_objects = binder_shrink_count,
1063         .scan_objects = binder_shrink_scan,
1064         .seeks = DEFAULT_SEEKS,
1065 };
1066
1067 /**
1068  * binder_alloc_init() - called by binder_open() for per-proc initialization
1069  * @alloc: binder_alloc for this proc
1070  *
1071  * Called from binder_open() to initialize binder_alloc fields for
1072  * new binder proc
1073  */
1074 void binder_alloc_init(struct binder_alloc *alloc)
1075 {
1076         alloc->pid = current->group_leader->pid;
1077         alloc->mm = current->mm;
1078         mmgrab(alloc->mm);
1079         mutex_init(&alloc->mutex);
1080         INIT_LIST_HEAD(&alloc->buffers);
1081 }
1082
1083 int binder_alloc_shrinker_init(void)
1084 {
1085         int ret = list_lru_init(&binder_alloc_lru);
1086
1087         if (ret == 0) {
1088                 ret = register_shrinker(&binder_shrinker, "android-binder");
1089                 if (ret)
1090                         list_lru_destroy(&binder_alloc_lru);
1091         }
1092         return ret;
1093 }
1094
1095 void binder_alloc_shrinker_exit(void)
1096 {
1097         unregister_shrinker(&binder_shrinker);
1098         list_lru_destroy(&binder_alloc_lru);
1099 }
1100
1101 /**
1102  * check_buffer() - verify that buffer/offset is safe to access
1103  * @alloc: binder_alloc for this proc
1104  * @buffer: binder buffer to be accessed
1105  * @offset: offset into @buffer data
1106  * @bytes: bytes to access from offset
1107  *
1108  * Check that the @offset/@bytes are within the size of the given
1109  * @buffer and that the buffer is currently active and not freeable.
1110  * Offsets must also be multiples of sizeof(u32). The kernel is
1111  * allowed to touch the buffer in two cases:
1112  *
1113  * 1) when the buffer is being created:
1114  *     (buffer->free == 0 && buffer->allow_user_free == 0)
1115  * 2) when the buffer is being torn down:
1116  *     (buffer->free == 0 && buffer->transaction == NULL).
1117  *
1118  * Return: true if the buffer is safe to access
1119  */
1120 static inline bool check_buffer(struct binder_alloc *alloc,
1121                                 struct binder_buffer *buffer,
1122                                 binder_size_t offset, size_t bytes)
1123 {
1124         size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1125
1126         return buffer_size >= bytes &&
1127                 offset <= buffer_size - bytes &&
1128                 IS_ALIGNED(offset, sizeof(u32)) &&
1129                 !buffer->free &&
1130                 (!buffer->allow_user_free || !buffer->transaction);
1131 }
1132
1133 /**
1134  * binder_alloc_get_page() - get kernel pointer for given buffer offset
1135  * @alloc: binder_alloc for this proc
1136  * @buffer: binder buffer to be accessed
1137  * @buffer_offset: offset into @buffer data
1138  * @pgoffp: address to copy final page offset to
1139  *
1140  * Lookup the struct page corresponding to the address
1141  * at @buffer_offset into @buffer->user_data. If @pgoffp is not
1142  * NULL, the byte-offset into the page is written there.
1143  *
1144  * The caller is responsible to ensure that the offset points
1145  * to a valid address within the @buffer and that @buffer is
1146  * not freeable by the user. Since it can't be freed, we are
1147  * guaranteed that the corresponding elements of @alloc->pages[]
1148  * cannot change.
1149  *
1150  * Return: struct page
1151  */
1152 static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1153                                           struct binder_buffer *buffer,
1154                                           binder_size_t buffer_offset,
1155                                           pgoff_t *pgoffp)
1156 {
1157         binder_size_t buffer_space_offset = buffer_offset +
1158                 (buffer->user_data - alloc->buffer);
1159         pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
1160         size_t index = buffer_space_offset >> PAGE_SHIFT;
1161         struct binder_lru_page *lru_page;
1162
1163         lru_page = &alloc->pages[index];
1164         *pgoffp = pgoff;
1165         return lru_page->page_ptr;
1166 }
1167
1168 /**
1169  * binder_alloc_clear_buf() - zero out buffer
1170  * @alloc: binder_alloc for this proc
1171  * @buffer: binder buffer to be cleared
1172  *
1173  * memset the given buffer to 0
1174  */
1175 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
1176                                    struct binder_buffer *buffer)
1177 {
1178         size_t bytes = binder_alloc_buffer_size(alloc, buffer);
1179         binder_size_t buffer_offset = 0;
1180
1181         while (bytes) {
1182                 unsigned long size;
1183                 struct page *page;
1184                 pgoff_t pgoff;
1185
1186                 page = binder_alloc_get_page(alloc, buffer,
1187                                              buffer_offset, &pgoff);
1188                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1189                 memset_page(page, pgoff, 0, size);
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_local_page(page) + pgoff;
1228                 ret = copy_from_user(kptr, from, size);
1229                 kunmap_local(kptr);
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
1255                 page = binder_alloc_get_page(alloc, buffer,
1256                                              buffer_offset, &pgoff);
1257                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1258                 if (to_buffer)
1259                         memcpy_to_page(page, pgoff, ptr, size);
1260                 else
1261                         memcpy_from_page(ptr, page, pgoff, size);
1262                 bytes -= size;
1263                 pgoff = 0;
1264                 ptr = ptr + size;
1265                 buffer_offset += size;
1266         }
1267         return 0;
1268 }
1269
1270 int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1271                                 struct binder_buffer *buffer,
1272                                 binder_size_t buffer_offset,
1273                                 void *src,
1274                                 size_t bytes)
1275 {
1276         return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1277                                            src, bytes);
1278 }
1279
1280 int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1281                                   void *dest,
1282                                   struct binder_buffer *buffer,
1283                                   binder_size_t buffer_offset,
1284                                   size_t bytes)
1285 {
1286         return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
1287                                            dest, bytes);
1288 }
1289