drivers/android/binder_alloc.c

   1 /* binder_alloc.c
   2  *
   3  * Android IPC Subsystem
   4  *
   5  * Copyright (C) 2007-2017 Google, Inc.
   6  *
   7  * This software is licensed under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation, and
   9  * may be copied, distributed, and modified under those terms.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  */
  17
  18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  19
  20 #include <asm/cacheflush.h>
  21 #include <linux/list.h>
  22 #include <linux/sched/mm.h>
  23 #include <linux/module.h>
  24 #include <linux/rtmutex.h>
  25 #include <linux/rbtree.h>
  26 #include <linux/seq_file.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/slab.h>
  29 #include <linux/sched.h>
  30 #include <linux/list_lru.h>
  31 #include "binder_alloc.h"
  32 #include "binder_trace.h"
  33
  34 struct list_lru binder_alloc_lru;
  35
  36 static DEFINE_MUTEX(binder_alloc_mmap_lock);
  37
  38 enum {
  39         BINDER_DEBUG_OPEN_CLOSE             = 1U << 1,
  40         BINDER_DEBUG_BUFFER_ALLOC           = 1U << 2,
  41         BINDER_DEBUG_BUFFER_ALLOC_ASYNC     = 1U << 3,
  42 };
  43 static uint32_t binder_alloc_debug_mask;
  44
  45 module_param_named(debug_mask, binder_alloc_debug_mask,
  46                    uint, 0644);
  47
  48 #define binder_alloc_debug(mask, x...) \
  49         do { \
  50                 if (binder_alloc_debug_mask & mask) \
  51                         pr_info(x); \
  52         } while (0)
  53
  54 static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
  55 {
  56         return list_entry(buffer->entry.next, struct binder_buffer, entry);
  57 }
  58
  59 static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
  60 {
  61         return list_entry(buffer->entry.prev, struct binder_buffer, entry);
  62 }
  63
  64 static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
  65                                        struct binder_buffer *buffer)
  66 {
  67         if (list_is_last(&buffer->entry, &alloc->buffers))
  68                 return (u8 *)alloc->buffer +
  69                         alloc->buffer_size - (u8 *)buffer->data;
  70         return (u8 *)binder_buffer_next(buffer)->data - (u8 *)buffer->data;
  71 }
  72
  73 static void binder_insert_free_buffer(struct binder_alloc *alloc,
  74                                       struct binder_buffer *new_buffer)
  75 {
  76         struct rb_node **p = &alloc->free_buffers.rb_node;
  77         struct rb_node *parent = NULL;
  78         struct binder_buffer *buffer;
  79         size_t buffer_size;
  80         size_t new_buffer_size;
  81
  82         BUG_ON(!new_buffer->free);
  83
  84         new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
  85
  86         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
  87                      "%d: add free buffer, size %zd, at %pK\n",
  88                       alloc->pid, new_buffer_size, new_buffer);
  89
  90         while (*p) {
  91                 parent = *p;
  92                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
  93                 BUG_ON(!buffer->free);
  94
  95                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
  96
  97                 if (new_buffer_size < buffer_size)
  98                         p = &parent->rb_left;
  99                 else
 100                         p = &parent->rb_right;
 101         }
 102         rb_link_node(&new_buffer->rb_node, parent, p);
 103         rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
 104 }
 105
 106 static void binder_insert_allocated_buffer_locked(
 107                 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
 108 {
 109         struct rb_node **p = &alloc->allocated_buffers.rb_node;
 110         struct rb_node *parent = NULL;
 111         struct binder_buffer *buffer;
 112
 113         BUG_ON(new_buffer->free);
 114
 115         while (*p) {
 116                 parent = *p;
 117                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
 118                 BUG_ON(buffer->free);
 119
 120                 if (new_buffer->data < buffer->data)
 121                         p = &parent->rb_left;
 122                 else if (new_buffer->data > buffer->data)
 123                         p = &parent->rb_right;
 124                 else
 125                         BUG();
 126         }
 127         rb_link_node(&new_buffer->rb_node, parent, p);
 128         rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
 129 }
 130
 131 static struct binder_buffer *binder_alloc_prepare_to_free_locked(
 132                 struct binder_alloc *alloc,
 133                 uintptr_t user_ptr)
 134 {
 135         struct rb_node *n = alloc->allocated_buffers.rb_node;
 136         struct binder_buffer *buffer;
 137         void *kern_ptr;
 138
 139         kern_ptr = (void *)(user_ptr - alloc->user_buffer_offset);
 140
 141         while (n) {
 142                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 143                 BUG_ON(buffer->free);
 144
 145                 if (kern_ptr < buffer->data)
 146                         n = n->rb_left;
 147                 else if (kern_ptr > buffer->data)
 148                         n = n->rb_right;
 149                 else {
 150                         /*
 151                          * Guard against user threads attempting to
 152                          * free the buffer twice
 153                          */
 154                         if (buffer->free_in_progress) {
 155                                 pr_err("%d:%d FREE_BUFFER u%016llx user freed buffer twice\n",
 156                                        alloc->pid, current->pid, (u64)user_ptr);
 157                                 return NULL;
 158                         }
 159                         buffer->free_in_progress = 1;
 160                         return buffer;
 161                 }
 162         }
 163         return NULL;
 164 }
 165
 166 /**
 167  * binder_alloc_buffer_lookup() - get buffer given user ptr
 168  * @alloc:      binder_alloc for this proc
 169  * @user_ptr:   User pointer to buffer data
 170  *
 171  * Validate userspace pointer to buffer data and return buffer corresponding to
 172  * that user pointer. Search the rb tree for buffer that matches user data
 173  * pointer.
 174  *
 175  * Return:      Pointer to buffer or NULL
 176  */
 177 struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
 178                                                    uintptr_t user_ptr)
 179 {
 180         struct binder_buffer *buffer;
 181
 182         mutex_lock(&alloc->mutex);
 183         buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
 184         mutex_unlock(&alloc->mutex);
 185         return buffer;
 186 }
 187
 188 static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
 189                                     void *start, void *end,
 190                                     struct vm_area_struct *vma)
 191 {
 192         void *page_addr;
 193         unsigned long user_page_addr;
 194         struct binder_lru_page *page;
 195         struct mm_struct *mm = NULL;
 196         bool need_mm = false;
 197
 198         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 199                      "%d: %s pages %pK-%pK\n", alloc->pid,
 200                      allocate ? "allocate" : "free", start, end);
 201
 202         if (end <= start)
 203                 return 0;
 204
 205         trace_binder_update_page_range(alloc, allocate, start, end);
 206
 207         if (allocate == 0)
 208                 goto free_range;
 209
 210         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 211                 page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
 212                 if (!page->page_ptr) {
 213                         need_mm = true;
 214                         break;
 215                 }
 216         }
 217
 218         if (!vma && need_mm && mmget_not_zero(alloc->vma_vm_mm))
 219                 mm = alloc->vma_vm_mm;
 220
 221         if (mm) {
 222                 down_write(&mm->mmap_sem);
 223                 vma = alloc->vma;
 224         }
 225
 226         if (!vma && need_mm) {
 227                 pr_err("%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
 228                         alloc->pid);
 229                 goto err_no_vma;
 230         }
 231
 232         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 233                 int ret;
 234                 bool on_lru;
 235                 size_t index;
 236
 237                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 238                 page = &alloc->pages[index];
 239
 240                 if (page->page_ptr) {
 241                         trace_binder_alloc_lru_start(alloc, index);
 242
 243                         on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
 244                         WARN_ON(!on_lru);
 245
 246                         trace_binder_alloc_lru_end(alloc, index);
 247                         continue;
 248                 }
 249
 250                 if (WARN_ON(!vma))
 251                         goto err_page_ptr_cleared;
 252
 253                 trace_binder_alloc_page_start(alloc, index);
 254                 page->page_ptr = alloc_page(GFP_KERNEL |
 255                                             __GFP_HIGHMEM |
 256                                             __GFP_ZERO);
 257                 if (!page->page_ptr) {
 258                         pr_err("%d: binder_alloc_buf failed for page at %pK\n",
 259                                 alloc->pid, page_addr);
 260                         goto err_alloc_page_failed;
 261                 }
 262                 page->alloc = alloc;
 263                 INIT_LIST_HEAD(&page->lru);
 264
 265                 ret = map_kernel_range_noflush((unsigned long)page_addr,
 266                                                PAGE_SIZE, PAGE_KERNEL,
 267                                                &page->page_ptr);
 268                 flush_cache_vmap((unsigned long)page_addr,
 269                                 (unsigned long)page_addr + PAGE_SIZE);
 270                 if (ret != 1) {
 271                         pr_err("%d: binder_alloc_buf failed to map page at %pK in kernel\n",
 272                                alloc->pid, page_addr);
 273                         goto err_map_kernel_failed;
 274                 }
 275                 user_page_addr =
 276                         (uintptr_t)page_addr + alloc->user_buffer_offset;
 277                 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
 278                 if (ret) {
 279                         pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
 280                                alloc->pid, user_page_addr);
 281                         goto err_vm_insert_page_failed;
 282                 }
 283
 284                 trace_binder_alloc_page_end(alloc, index);
 285                 /* vm_insert_page does not seem to increment the refcount */
 286         }
 287         if (mm) {
 288                 up_write(&mm->mmap_sem);
 289                 mmput(mm);
 290         }
 291         return 0;
 292
 293 free_range:
 294         for (page_addr = end - PAGE_SIZE; page_addr >= start;
 295              page_addr -= PAGE_SIZE) {
 296                 bool ret;
 297                 size_t index;
 298
 299                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 300                 page = &alloc->pages[index];
 301
 302                 trace_binder_free_lru_start(alloc, index);
 303
 304                 ret = list_lru_add(&binder_alloc_lru, &page->lru);
 305                 WARN_ON(!ret);
 306
 307                 trace_binder_free_lru_end(alloc, index);
 308                 continue;
 309
 310 err_vm_insert_page_failed:
 311                 unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
 312 err_map_kernel_failed:
 313                 __free_page(page->page_ptr);
 314                 page->page_ptr = NULL;
 315 err_alloc_page_failed:
 316 err_page_ptr_cleared:
 317                 ;
 318         }
 319 err_no_vma:
 320         if (mm) {
 321                 up_write(&mm->mmap_sem);
 322                 mmput(mm);
 323         }
 324         return vma ? -ENOMEM : -ESRCH;
 325 }
 326
 327 struct binder_buffer *binder_alloc_new_buf_locked(struct binder_alloc *alloc,
 328                                                   size_t data_size,
 329                                                   size_t offsets_size,
 330                                                   size_t extra_buffers_size,
 331                                                   int is_async)
 332 {
 333         struct rb_node *n = alloc->free_buffers.rb_node;
 334         struct binder_buffer *buffer;
 335         size_t buffer_size;
 336         struct rb_node *best_fit = NULL;
 337         void *has_page_addr;
 338         void *end_page_addr;
 339         size_t size, data_offsets_size;
 340         int ret;
 341
 342         if (alloc->vma == NULL) {
 343                 pr_err("%d: binder_alloc_buf, no vma\n",
 344                        alloc->pid);
 345                 return ERR_PTR(-ESRCH);
 346         }
 347
 348         data_offsets_size = ALIGN(data_size, sizeof(void *)) +
 349                 ALIGN(offsets_size, sizeof(void *));
 350
 351         if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
 352                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 353                                 "%d: got transaction with invalid size %zd-%zd\n",
 354                                 alloc->pid, data_size, offsets_size);
 355                 return ERR_PTR(-EINVAL);
 356         }
 357         size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
 358         if (size < data_offsets_size || size < extra_buffers_size) {
 359                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 360                                 "%d: got transaction with invalid extra_buffers_size %zd\n",
 361                                 alloc->pid, extra_buffers_size);
 362                 return ERR_PTR(-EINVAL);
 363         }
 364         if (is_async &&
 365             alloc->free_async_space < size + sizeof(struct binder_buffer)) {
 366                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 367                              "%d: binder_alloc_buf size %zd failed, no async space left\n",
 368                               alloc->pid, size);
 369                 return ERR_PTR(-ENOSPC);
 370         }
 371
 372         /* Pad 0-size buffers so they get assigned unique addresses */
 373         size = max(size, sizeof(void *));
 374
 375         while (n) {
 376                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 377                 BUG_ON(!buffer->free);
 378                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 379
 380                 if (size < buffer_size) {
 381                         best_fit = n;
 382                         n = n->rb_left;
 383                 } else if (size > buffer_size)
 384                         n = n->rb_right;
 385                 else {
 386                         best_fit = n;
 387                         break;
 388                 }
 389         }
 390         if (best_fit == NULL) {
 391                 size_t allocated_buffers = 0;
 392                 size_t largest_alloc_size = 0;
 393                 size_t total_alloc_size = 0;
 394                 size_t free_buffers = 0;
 395                 size_t largest_free_size = 0;
 396                 size_t total_free_size = 0;
 397
 398                 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 399                      n = rb_next(n)) {
 400                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 401                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 402                         allocated_buffers++;
 403                         total_alloc_size += buffer_size;
 404                         if (buffer_size > largest_alloc_size)
 405                                 largest_alloc_size = buffer_size;
 406                 }
 407                 for (n = rb_first(&alloc->free_buffers); n != NULL;
 408                      n = rb_next(n)) {
 409                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 410                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 411                         free_buffers++;
 412                         total_free_size += buffer_size;
 413                         if (buffer_size > largest_free_size)
 414                                 largest_free_size = buffer_size;
 415                 }
 416                 pr_err("%d: binder_alloc_buf size %zd failed, no address space\n",
 417                         alloc->pid, size);
 418                 pr_err("allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
 419                        total_alloc_size, allocated_buffers, largest_alloc_size,
 420                        total_free_size, free_buffers, largest_free_size);
 421                 return ERR_PTR(-ENOSPC);
 422         }
 423         if (n == NULL) {
 424                 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
 425                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 426         }
 427
 428         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 429                      "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
 430                       alloc->pid, size, buffer, buffer_size);
 431
 432         has_page_addr =
 433                 (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK);
 434         WARN_ON(n && buffer_size != size);
 435         end_page_addr =
 436                 (void *)PAGE_ALIGN((uintptr_t)buffer->data + size);
 437         if (end_page_addr > has_page_addr)
 438                 end_page_addr = has_page_addr;
 439         ret = binder_update_page_range(alloc, 1,
 440             (void *)PAGE_ALIGN((uintptr_t)buffer->data), end_page_addr, NULL);
 441         if (ret)
 442                 return ERR_PTR(ret);
 443
 444         if (buffer_size != size) {
 445                 struct binder_buffer *new_buffer;
 446
 447                 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 448                 if (!new_buffer) {
 449                         pr_err("%s: %d failed to alloc new buffer struct\n",
 450                                __func__, alloc->pid);
 451                         goto err_alloc_buf_struct_failed;
 452                 }
 453                 new_buffer->data = (u8 *)buffer->data + size;
 454                 list_add(&new_buffer->entry, &buffer->entry);
 455                 new_buffer->free = 1;
 456                 binder_insert_free_buffer(alloc, new_buffer);
 457         }
 458
 459         rb_erase(best_fit, &alloc->free_buffers);
 460         buffer->free = 0;
 461         buffer->free_in_progress = 0;
 462         binder_insert_allocated_buffer_locked(alloc, buffer);
 463         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 464                      "%d: binder_alloc_buf size %zd got %pK\n",
 465                       alloc->pid, size, buffer);
 466         buffer->data_size = data_size;
 467         buffer->offsets_size = offsets_size;
 468         buffer->async_transaction = is_async;
 469         buffer->extra_buffers_size = extra_buffers_size;
 470         if (is_async) {
 471                 alloc->free_async_space -= size + sizeof(struct binder_buffer);
 472                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 473                              "%d: binder_alloc_buf size %zd async free %zd\n",
 474                               alloc->pid, size, alloc->free_async_space);
 475         }
 476         return buffer;
 477
 478 err_alloc_buf_struct_failed:
 479         binder_update_page_range(alloc, 0,
 480                                  (void *)PAGE_ALIGN((uintptr_t)buffer->data),
 481                                  end_page_addr, NULL);
 482         return ERR_PTR(-ENOMEM);
 483 }
 484
 485 /**
 486  * binder_alloc_new_buf() - Allocate a new binder buffer
 487  * @alloc:              binder_alloc for this proc
 488  * @data_size:          size of user data buffer
 489  * @offsets_size:       user specified buffer offset
 490  * @extra_buffers_size: size of extra space for meta-data (eg, security context)
 491  * @is_async:           buffer for async transaction
 492  *
 493  * Allocate a new buffer given the requested sizes. Returns
 494  * the kernel version of the buffer pointer. The size allocated
 495  * is the sum of the three given sizes (each rounded up to
 496  * pointer-sized boundary)
 497  *
 498  * Return:      The allocated buffer or %NULL if error
 499  */
 500 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 501                                            size_t data_size,
 502                                            size_t offsets_size,
 503                                            size_t extra_buffers_size,
 504                                            int is_async)
 505 {
 506         struct binder_buffer *buffer;
 507
 508         mutex_lock(&alloc->mutex);
 509         buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
 510                                              extra_buffers_size, is_async);
 511         mutex_unlock(&alloc->mutex);
 512         return buffer;
 513 }
 514
 515 static void *buffer_start_page(struct binder_buffer *buffer)
 516 {
 517         return (void *)((uintptr_t)buffer->data & PAGE_MASK);
 518 }
 519
 520 static void *prev_buffer_end_page(struct binder_buffer *buffer)
 521 {
 522         return (void *)(((uintptr_t)(buffer->data) - 1) & PAGE_MASK);
 523 }
 524
 525 static void binder_delete_free_buffer(struct binder_alloc *alloc,
 526                                       struct binder_buffer *buffer)
 527 {
 528         struct binder_buffer *prev, *next = NULL;
 529         bool to_free = true;
 530         BUG_ON(alloc->buffers.next == &buffer->entry);
 531         prev = binder_buffer_prev(buffer);
 532         BUG_ON(!prev->free);
 533         if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
 534                 to_free = false;
 535                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 536                                    "%d: merge free, buffer %pK share page with %pK\n",
 537                                    alloc->pid, buffer->data, prev->data);
 538         }
 539
 540         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 541                 next = binder_buffer_next(buffer);
 542                 if (buffer_start_page(next) == buffer_start_page(buffer)) {
 543                         to_free = false;
 544                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 545                                            "%d: merge free, buffer %pK share page with %pK\n",
 546                                            alloc->pid,
 547                                            buffer->data,
 548                                            next->data);
 549                 }
 550         }
 551
 552         if (PAGE_ALIGNED(buffer->data)) {
 553                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 554                                    "%d: merge free, buffer start %pK is page aligned\n",
 555                                    alloc->pid, buffer->data);
 556                 to_free = false;
 557         }
 558
 559         if (to_free) {
 560                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 561                                    "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
 562                                    alloc->pid, buffer->data,
 563                                    prev->data, next ? next->data : NULL);
 564                 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
 565                                          buffer_start_page(buffer) + PAGE_SIZE,
 566                                          NULL);
 567         }
 568         list_del(&buffer->entry);
 569         kfree(buffer);
 570 }
 571
 572 static void binder_free_buf_locked(struct binder_alloc *alloc,
 573                                    struct binder_buffer *buffer)
 574 {
 575         size_t size, buffer_size;
 576
 577         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 578
 579         size = ALIGN(buffer->data_size, sizeof(void *)) +
 580                 ALIGN(buffer->offsets_size, sizeof(void *)) +
 581                 ALIGN(buffer->extra_buffers_size, sizeof(void *));
 582
 583         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 584                      "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
 585                       alloc->pid, buffer, size, buffer_size);
 586
 587         BUG_ON(buffer->free);
 588         BUG_ON(size > buffer_size);
 589         BUG_ON(buffer->transaction != NULL);
 590         BUG_ON(buffer->data < alloc->buffer);
 591         BUG_ON(buffer->data > alloc->buffer + alloc->buffer_size);
 592
 593         if (buffer->async_transaction) {
 594                 alloc->free_async_space += size + sizeof(struct binder_buffer);
 595
 596                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 597                              "%d: binder_free_buf size %zd async free %zd\n",
 598                               alloc->pid, size, alloc->free_async_space);
 599         }
 600
 601         binder_update_page_range(alloc, 0,
 602                 (void *)PAGE_ALIGN((uintptr_t)buffer->data),
 603                 (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK),
 604                 NULL);
 605
 606         rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
 607         buffer->free = 1;
 608         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 609                 struct binder_buffer *next = binder_buffer_next(buffer);
 610
 611                 if (next->free) {
 612                         rb_erase(&next->rb_node, &alloc->free_buffers);
 613                         binder_delete_free_buffer(alloc, next);
 614                 }
 615         }
 616         if (alloc->buffers.next != &buffer->entry) {
 617                 struct binder_buffer *prev = binder_buffer_prev(buffer);
 618
 619                 if (prev->free) {
 620                         binder_delete_free_buffer(alloc, buffer);
 621                         rb_erase(&prev->rb_node, &alloc->free_buffers);
 622                         buffer = prev;
 623                 }
 624         }
 625         binder_insert_free_buffer(alloc, buffer);
 626 }
 627
 628 /**
 629  * binder_alloc_free_buf() - free a binder buffer
 630  * @alloc:      binder_alloc for this proc
 631  * @buffer:     kernel pointer to buffer
 632  *
 633  * Free the buffer allocated via binder_alloc_new_buffer()
 634  */
 635 void binder_alloc_free_buf(struct binder_alloc *alloc,
 636                             struct binder_buffer *buffer)
 637 {
 638         mutex_lock(&alloc->mutex);
 639         binder_free_buf_locked(alloc, buffer);
 640         mutex_unlock(&alloc->mutex);
 641 }
 642
 643 /**
 644  * binder_alloc_mmap_handler() - map virtual address space for proc
 645  * @alloc:      alloc structure for this proc
 646  * @vma:        vma passed to mmap()
 647  *
 648  * Called by binder_mmap() to initialize the space specified in
 649  * vma for allocating binder buffers
 650  *
 651  * Return:
 652  *      0 = success
 653  *      -EBUSY = address space already mapped
 654  *      -ENOMEM = failed to map memory to given address space
 655  */
 656 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 657                               struct vm_area_struct *vma)
 658 {
 659         int ret;
 660         struct vm_struct *area;
 661         const char *failure_string;
 662         struct binder_buffer *buffer;
 663
 664         mutex_lock(&binder_alloc_mmap_lock);
 665         if (alloc->buffer) {
 666                 ret = -EBUSY;
 667                 failure_string = "already mapped";
 668                 goto err_already_mapped;
 669         }
 670
 671         area = get_vm_area(vma->vm_end - vma->vm_start, VM_IOREMAP);
 672         if (area == NULL) {
 673                 ret = -ENOMEM;
 674                 failure_string = "get_vm_area";
 675                 goto err_get_vm_area_failed;
 676         }
 677         alloc->buffer = area->addr;
 678         alloc->user_buffer_offset =
 679                 vma->vm_start - (uintptr_t)alloc->buffer;
 680         mutex_unlock(&binder_alloc_mmap_lock);
 681
 682 #ifdef CONFIG_CPU_CACHE_VIPT
 683         if (cache_is_vipt_aliasing()) {
 684                 while (CACHE_COLOUR(
 685                                 (vma->vm_start ^ (uint32_t)alloc->buffer))) {
 686                         pr_info("%s: %d %lx-%lx maps %pK bad alignment\n",
 687                                 __func__, alloc->pid, vma->vm_start,
 688                                 vma->vm_end, alloc->buffer);
 689                         vma->vm_start += PAGE_SIZE;
 690                 }
 691         }
 692 #endif
 693         alloc->pages = kzalloc(sizeof(alloc->pages[0]) *
 694                                    ((vma->vm_end - vma->vm_start) / PAGE_SIZE),
 695                                GFP_KERNEL);
 696         if (alloc->pages == NULL) {
 697                 ret = -ENOMEM;
 698                 failure_string = "alloc page array";
 699                 goto err_alloc_pages_failed;
 700         }
 701         alloc->buffer_size = vma->vm_end - vma->vm_start;
 702
 703         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 704         if (!buffer) {
 705                 ret = -ENOMEM;
 706                 failure_string = "alloc buffer struct";
 707                 goto err_alloc_buf_struct_failed;
 708         }
 709
 710         buffer->data = alloc->buffer;
 711         list_add(&buffer->entry, &alloc->buffers);
 712         buffer->free = 1;
 713         binder_insert_free_buffer(alloc, buffer);
 714         alloc->free_async_space = alloc->buffer_size / 2;
 715         barrier();
 716         alloc->vma = vma;
 717         alloc->vma_vm_mm = vma->vm_mm;
 718         mmgrab(alloc->vma_vm_mm);
 719
 720         return 0;
 721
 722 err_alloc_buf_struct_failed:
 723         kfree(alloc->pages);
 724         alloc->pages = NULL;
 725 err_alloc_pages_failed:
 726         mutex_lock(&binder_alloc_mmap_lock);
 727         vfree(alloc->buffer);
 728         alloc->buffer = NULL;
 729 err_get_vm_area_failed:
 730 err_already_mapped:
 731         mutex_unlock(&binder_alloc_mmap_lock);
 732         pr_err("%s: %d %lx-%lx %s failed %d\n", __func__,
 733                alloc->pid, vma->vm_start, vma->vm_end, failure_string, ret);
 734         return ret;
 735 }
 736
 737
 738 void binder_alloc_deferred_release(struct binder_alloc *alloc)
 739 {
 740         struct rb_node *n;
 741         int buffers, page_count;
 742         struct binder_buffer *buffer;
 743
 744         BUG_ON(alloc->vma);
 745
 746         buffers = 0;
 747         mutex_lock(&alloc->mutex);
 748         while ((n = rb_first(&alloc->allocated_buffers))) {
 749                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 750
 751                 /* Transaction should already have been freed */
 752                 BUG_ON(buffer->transaction);
 753
 754                 binder_free_buf_locked(alloc, buffer);
 755                 buffers++;
 756         }
 757
 758         while (!list_empty(&alloc->buffers)) {
 759                 buffer = list_first_entry(&alloc->buffers,
 760                                           struct binder_buffer, entry);
 761                 WARN_ON(!buffer->free);
 762
 763                 list_del(&buffer->entry);
 764                 WARN_ON_ONCE(!list_empty(&alloc->buffers));
 765                 kfree(buffer);
 766         }
 767
 768         page_count = 0;
 769         if (alloc->pages) {
 770                 int i;
 771
 772                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 773                         void *page_addr;
 774                         bool on_lru;
 775
 776                         if (!alloc->pages[i].page_ptr)
 777                                 continue;
 778
 779                         on_lru = list_lru_del(&binder_alloc_lru,
 780                                               &alloc->pages[i].lru);
 781                         page_addr = alloc->buffer + i * PAGE_SIZE;
 782                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 783                                      "%s: %d: page %d at %pK %s\n",
 784                                      __func__, alloc->pid, i, page_addr,
 785                                      on_lru ? "on lru" : "active");
 786                         unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
 787                         __free_page(alloc->pages[i].page_ptr);
 788                         page_count++;
 789                 }
 790                 kfree(alloc->pages);
 791                 vfree(alloc->buffer);
 792         }
 793         mutex_unlock(&alloc->mutex);
 794         if (alloc->vma_vm_mm)
 795                 mmdrop(alloc->vma_vm_mm);
 796
 797         binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
 798                      "%s: %d buffers %d, pages %d\n",
 799                      __func__, alloc->pid, buffers, page_count);
 800 }
 801
 802 static void print_binder_buffer(struct seq_file *m, const char *prefix,
 803                                 struct binder_buffer *buffer)
 804 {
 805         seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
 806                    prefix, buffer->debug_id, buffer->data,
 807                    buffer->data_size, buffer->offsets_size,
 808                    buffer->extra_buffers_size,
 809                    buffer->transaction ? "active" : "delivered");
 810 }
 811
 812 /**
 813  * binder_alloc_print_allocated() - print buffer info
 814  * @m:     seq_file for output via seq_printf()
 815  * @alloc: binder_alloc for this proc
 816  *
 817  * Prints information about every buffer associated with
 818  * the binder_alloc state to the given seq_file
 819  */
 820 void binder_alloc_print_allocated(struct seq_file *m,
 821                                   struct binder_alloc *alloc)
 822 {
 823         struct rb_node *n;
 824
 825         mutex_lock(&alloc->mutex);
 826         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 827                 print_binder_buffer(m, "  buffer",
 828                                     rb_entry(n, struct binder_buffer, rb_node));
 829         mutex_unlock(&alloc->mutex);
 830 }
 831
 832 /**
 833  * binder_alloc_print_pages() - print page usage
 834  * @m:     seq_file for output via seq_printf()
 835  * @alloc: binder_alloc for this proc
 836  */
 837 void binder_alloc_print_pages(struct seq_file *m,
 838                               struct binder_alloc *alloc)
 839 {
 840         struct binder_lru_page *page;
 841         int i;
 842         int active = 0;
 843         int lru = 0;
 844         int free = 0;
 845
 846         mutex_lock(&alloc->mutex);
 847         for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 848                 page = &alloc->pages[i];
 849                 if (!page->page_ptr)
 850                         free++;
 851                 else if (list_empty(&page->lru))
 852                         active++;
 853                 else
 854                         lru++;
 855         }
 856         mutex_unlock(&alloc->mutex);
 857         seq_printf(m, "  pages: %d:%d:%d\n", active, lru, free);
 858 }
 859
 860 /**
 861  * binder_alloc_get_allocated_count() - return count of buffers
 862  * @alloc: binder_alloc for this proc
 863  *
 864  * Return: count of allocated buffers
 865  */
 866 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
 867 {
 868         struct rb_node *n;
 869         int count = 0;
 870
 871         mutex_lock(&alloc->mutex);
 872         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 873                 count++;
 874         mutex_unlock(&alloc->mutex);
 875         return count;
 876 }
 877
 878
 879 /**
 880  * binder_alloc_vma_close() - invalidate address space
 881  * @alloc: binder_alloc for this proc
 882  *
 883  * Called from binder_vma_close() when releasing address space.
 884  * Clears alloc->vma to prevent new incoming transactions from
 885  * allocating more buffers.
 886  */
 887 void binder_alloc_vma_close(struct binder_alloc *alloc)
 888 {
 889         WRITE_ONCE(alloc->vma, NULL);
 890 }
 891
 892 /**
 893  * binder_alloc_free_page() - shrinker callback to free pages
 894  * @item:   item to free
 895  * @lock:   lock protecting the item
 896  * @cb_arg: callback argument
 897  *
 898  * Called from list_lru_walk() in binder_shrink_scan() to free
 899  * up pages when the system is under memory pressure.
 900  */
 901 enum lru_status binder_alloc_free_page(struct list_head *item,
 902                                        struct list_lru_one *lru,
 903                                        spinlock_t *lock,
 904                                        void *cb_arg)
 905 {
 906         struct mm_struct *mm = NULL;
 907         struct binder_lru_page *page = container_of(item,
 908                                                     struct binder_lru_page,
 909                                                     lru);
 910         struct binder_alloc *alloc;
 911         uintptr_t page_addr;
 912         size_t index;
 913         struct vm_area_struct *vma;
 914
 915         alloc = page->alloc;
 916         if (!mutex_trylock(&alloc->mutex))
 917                 goto err_get_alloc_mutex_failed;
 918
 919         if (!page->page_ptr)
 920                 goto err_page_already_freed;
 921
 922         index = page - alloc->pages;
 923         page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
 924         vma = alloc->vma;
 925         if (vma) {
 926                 if (!mmget_not_zero(alloc->vma_vm_mm))
 927                         goto err_mmget;
 928                 mm = alloc->vma_vm_mm;
 929                 if (!down_write_trylock(&mm->mmap_sem))
 930                         goto err_down_write_mmap_sem_failed;
 931         }
 932
 933         list_lru_isolate(lru, item);
 934         spin_unlock(lock);
 935
 936         if (vma) {
 937                 trace_binder_unmap_user_start(alloc, index);
 938
 939                 zap_page_range(vma,
 940                                page_addr + alloc->user_buffer_offset,
 941                                PAGE_SIZE);
 942
 943                 trace_binder_unmap_user_end(alloc, index);
 944
 945                 up_write(&mm->mmap_sem);
 946                 mmput(mm);
 947         }
 948
 949         trace_binder_unmap_kernel_start(alloc, index);
 950
 951         unmap_kernel_range(page_addr, PAGE_SIZE);
 952         __free_page(page->page_ptr);
 953         page->page_ptr = NULL;
 954
 955         trace_binder_unmap_kernel_end(alloc, index);
 956
 957         spin_lock(lock);
 958         mutex_unlock(&alloc->mutex);
 959         return LRU_REMOVED_RETRY;
 960
 961 err_down_write_mmap_sem_failed:
 962         mmput_async(mm);
 963 err_mmget:
 964 err_page_already_freed:
 965         mutex_unlock(&alloc->mutex);
 966 err_get_alloc_mutex_failed:
 967         return LRU_SKIP;
 968 }
 969
 970 static unsigned long
 971 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 972 {
 973         unsigned long ret = list_lru_count(&binder_alloc_lru);
 974         return ret;
 975 }
 976
 977 static unsigned long
 978 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 979 {
 980         unsigned long ret;
 981
 982         ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
 983                             NULL, sc->nr_to_scan);
 984         return ret;
 985 }
 986
 987 struct shrinker binder_shrinker = {
 988         .count_objects = binder_shrink_count,
 989         .scan_objects = binder_shrink_scan,
 990         .seeks = DEFAULT_SEEKS,
 991 };
 992
 993 /**
 994  * binder_alloc_init() - called by binder_open() for per-proc initialization
 995  * @alloc: binder_alloc for this proc
 996  *
 997  * Called from binder_open() to initialize binder_alloc fields for
 998  * new binder proc
 999  */
1000 void binder_alloc_init(struct binder_alloc *alloc)
1001 {
1002         alloc->pid = current->group_leader->pid;
1003         mutex_init(&alloc->mutex);
1004         INIT_LIST_HEAD(&alloc->buffers);
1005 }
1006
1007 void binder_alloc_shrinker_init(void)
1008 {
1009         list_lru_init(&binder_alloc_lru);
1010         register_shrinker(&binder_shrinker);
1011 }