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 <linux/list.h>
  21 #include <linux/sched/mm.h>
  22 #include <linux/module.h>
  23 #include <linux/rtmutex.h>
  24 #include <linux/rbtree.h>
  25 #include <linux/seq_file.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/slab.h>
  28 #include <linux/sched.h>
  29 #include <linux/list_lru.h>
  30 #include <linux/ratelimit.h>
  31 #include <asm/cacheflush.h>
  32 #include "binder_alloc.h"
  33 #include "binder_trace.h"
  34
  35 struct list_lru binder_alloc_lru;
  36
  37 static DEFINE_MUTEX(binder_alloc_mmap_lock);
  38
  39 enum {
  40         BINDER_DEBUG_USER_ERROR             = 1U << 0,
  41         BINDER_DEBUG_OPEN_CLOSE             = 1U << 1,
  42         BINDER_DEBUG_BUFFER_ALLOC           = 1U << 2,
  43         BINDER_DEBUG_BUFFER_ALLOC_ASYNC     = 1U << 3,
  44 };
  45 static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
  46
  47 module_param_named(debug_mask, binder_alloc_debug_mask,
  48                    uint, 0644);
  49
  50 #define binder_alloc_debug(mask, x...) \
  51         do { \
  52                 if (binder_alloc_debug_mask & mask) \
  53                         pr_info_ratelimited(x); \
  54         } while (0)
  55
  56 static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
  57 {
  58         return list_entry(buffer->entry.next, struct binder_buffer, entry);
  59 }
  60
  61 static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
  62 {
  63         return list_entry(buffer->entry.prev, struct binder_buffer, entry);
  64 }
  65
  66 static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
  67                                        struct binder_buffer *buffer)
  68 {
  69         if (list_is_last(&buffer->entry, &alloc->buffers))
  70                 return (u8 *)alloc->buffer +
  71                         alloc->buffer_size - (u8 *)buffer->data;
  72         return (u8 *)binder_buffer_next(buffer)->data - (u8 *)buffer->data;
  73 }
  74
  75 static void binder_insert_free_buffer(struct binder_alloc *alloc,
  76                                       struct binder_buffer *new_buffer)
  77 {
  78         struct rb_node **p = &alloc->free_buffers.rb_node;
  79         struct rb_node *parent = NULL;
  80         struct binder_buffer *buffer;
  81         size_t buffer_size;
  82         size_t new_buffer_size;
  83
  84         BUG_ON(!new_buffer->free);
  85
  86         new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
  87
  88         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
  89                      "%d: add free buffer, size %zd, at %pK\n",
  90                       alloc->pid, new_buffer_size, new_buffer);
  91
  92         while (*p) {
  93                 parent = *p;
  94                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
  95                 BUG_ON(!buffer->free);
  96
  97                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
  98
  99                 if (new_buffer_size < buffer_size)
 100                         p = &parent->rb_left;
 101                 else
 102                         p = &parent->rb_right;
 103         }
 104         rb_link_node(&new_buffer->rb_node, parent, p);
 105         rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
 106 }
 107
 108 static void binder_insert_allocated_buffer_locked(
 109                 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
 110 {
 111         struct rb_node **p = &alloc->allocated_buffers.rb_node;
 112         struct rb_node *parent = NULL;
 113         struct binder_buffer *buffer;
 114
 115         BUG_ON(new_buffer->free);
 116
 117         while (*p) {
 118                 parent = *p;
 119                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
 120                 BUG_ON(buffer->free);
 121
 122                 if (new_buffer->data < buffer->data)
 123                         p = &parent->rb_left;
 124                 else if (new_buffer->data > buffer->data)
 125                         p = &parent->rb_right;
 126                 else
 127                         BUG();
 128         }
 129         rb_link_node(&new_buffer->rb_node, parent, p);
 130         rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
 131 }
 132
 133 static struct binder_buffer *binder_alloc_prepare_to_free_locked(
 134                 struct binder_alloc *alloc,
 135                 uintptr_t user_ptr)
 136 {
 137         struct rb_node *n = alloc->allocated_buffers.rb_node;
 138         struct binder_buffer *buffer;
 139         void *kern_ptr;
 140
 141         kern_ptr = (void *)(user_ptr - alloc->user_buffer_offset);
 142
 143         while (n) {
 144                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 145                 BUG_ON(buffer->free);
 146
 147                 if (kern_ptr < buffer->data)
 148                         n = n->rb_left;
 149                 else if (kern_ptr > buffer->data)
 150                         n = n->rb_right;
 151                 else {
 152                         /*
 153                          * Guard against user threads attempting to
 154                          * free the buffer when in use by kernel or
 155                          * after it's already been freed.
 156                          */
 157                         if (!buffer->allow_user_free)
 158                                 return ERR_PTR(-EPERM);
 159                         buffer->allow_user_free = 0;
 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 {
 191         void *page_addr;
 192         unsigned long user_page_addr;
 193         struct binder_lru_page *page;
 194         struct vm_area_struct *vma = NULL;
 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 (need_mm && mmget_not_zero(alloc->vma_vm_mm))
 219                 mm = alloc->vma_vm_mm;
 220
 221         if (mm) {
 222                 down_read(&mm->mmap_sem);
 223                 vma = alloc->vma;
 224         }
 225
 226         if (!vma && need_mm) {
 227                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 228                                    "%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
 229                                    alloc->pid);
 230                 goto err_no_vma;
 231         }
 232
 233         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 234                 int ret;
 235                 bool on_lru;
 236                 size_t index;
 237
 238                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 239                 page = &alloc->pages[index];
 240
 241                 if (page->page_ptr) {
 242                         trace_binder_alloc_lru_start(alloc, index);
 243
 244                         on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
 245                         WARN_ON(!on_lru);
 246
 247                         trace_binder_alloc_lru_end(alloc, index);
 248                         continue;
 249                 }
 250
 251                 if (WARN_ON(!vma))
 252                         goto err_page_ptr_cleared;
 253
 254                 trace_binder_alloc_page_start(alloc, index);
 255                 page->page_ptr = alloc_page(GFP_KERNEL |
 256                                             __GFP_HIGHMEM |
 257                                             __GFP_ZERO);
 258                 if (!page->page_ptr) {
 259                         pr_err("%d: binder_alloc_buf failed for page at %pK\n",
 260                                 alloc->pid, page_addr);
 261                         goto err_alloc_page_failed;
 262                 }
 263                 page->alloc = alloc;
 264                 INIT_LIST_HEAD(&page->lru);
 265
 266                 ret = map_kernel_range_noflush((unsigned long)page_addr,
 267                                                PAGE_SIZE, PAGE_KERNEL,
 268                                                &page->page_ptr);
 269                 flush_cache_vmap((unsigned long)page_addr,
 270                                 (unsigned long)page_addr + PAGE_SIZE);
 271                 if (ret != 1) {
 272                         pr_err("%d: binder_alloc_buf failed to map page at %pK in kernel\n",
 273                                alloc->pid, page_addr);
 274                         goto err_map_kernel_failed;
 275                 }
 276                 user_page_addr =
 277                         (uintptr_t)page_addr + alloc->user_buffer_offset;
 278                 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
 279                 if (ret) {
 280                         pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
 281                                alloc->pid, user_page_addr);
 282                         goto err_vm_insert_page_failed;
 283                 }
 284
 285                 if (index + 1 > alloc->pages_high)
 286                         alloc->pages_high = index + 1;
 287
 288                 trace_binder_alloc_page_end(alloc, index);
 289                 /* vm_insert_page does not seem to increment the refcount */
 290         }
 291         if (mm) {
 292                 up_read(&mm->mmap_sem);
 293                 mmput(mm);
 294         }
 295         return 0;
 296
 297 free_range:
 298         for (page_addr = end - PAGE_SIZE; page_addr >= start;
 299              page_addr -= PAGE_SIZE) {
 300                 bool ret;
 301                 size_t index;
 302
 303                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 304                 page = &alloc->pages[index];
 305
 306                 trace_binder_free_lru_start(alloc, index);
 307
 308                 ret = list_lru_add(&binder_alloc_lru, &page->lru);
 309                 WARN_ON(!ret);
 310
 311                 trace_binder_free_lru_end(alloc, index);
 312                 continue;
 313
 314 err_vm_insert_page_failed:
 315                 unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
 316 err_map_kernel_failed:
 317                 __free_page(page->page_ptr);
 318                 page->page_ptr = NULL;
 319 err_alloc_page_failed:
 320 err_page_ptr_cleared:
 321                 ;
 322         }
 323 err_no_vma:
 324         if (mm) {
 325                 up_read(&mm->mmap_sem);
 326                 mmput(mm);
 327         }
 328         return vma ? -ENOMEM : -ESRCH;
 329 }
 330
 331
 332 static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
 333                 struct vm_area_struct *vma)
 334 {
 335         if (vma)
 336                 alloc->vma_vm_mm = vma->vm_mm;
 337         /*
 338          * If we see alloc->vma is not NULL, buffer data structures set up
 339          * completely. Look at smp_rmb side binder_alloc_get_vma.
 340          * We also want to guarantee new alloc->vma_vm_mm is always visible
 341          * if alloc->vma is set.
 342          */
 343         smp_wmb();
 344         alloc->vma = vma;
 345 }
 346
 347 static inline struct vm_area_struct *binder_alloc_get_vma(
 348                 struct binder_alloc *alloc)
 349 {
 350         struct vm_area_struct *vma = NULL;
 351
 352         if (alloc->vma) {
 353                 /* Look at description in binder_alloc_set_vma */
 354                 smp_rmb();
 355                 vma = alloc->vma;
 356         }
 357         return vma;
 358 }
 359
 360 static struct binder_buffer *binder_alloc_new_buf_locked(
 361                                 struct binder_alloc *alloc,
 362                                 size_t data_size,
 363                                 size_t offsets_size,
 364                                 size_t extra_buffers_size,
 365                                 int is_async)
 366 {
 367         struct rb_node *n = alloc->free_buffers.rb_node;
 368         struct binder_buffer *buffer;
 369         size_t buffer_size;
 370         struct rb_node *best_fit = NULL;
 371         void *has_page_addr;
 372         void *end_page_addr;
 373         size_t size, data_offsets_size;
 374         int ret;
 375
 376         if (!binder_alloc_get_vma(alloc)) {
 377                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 378                                    "%d: binder_alloc_buf, no vma\n",
 379                                    alloc->pid);
 380                 return ERR_PTR(-ESRCH);
 381         }
 382
 383         data_offsets_size = ALIGN(data_size, sizeof(void *)) +
 384                 ALIGN(offsets_size, sizeof(void *));
 385
 386         if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
 387                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 388                                 "%d: got transaction with invalid size %zd-%zd\n",
 389                                 alloc->pid, data_size, offsets_size);
 390                 return ERR_PTR(-EINVAL);
 391         }
 392         size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
 393         if (size < data_offsets_size || size < extra_buffers_size) {
 394                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 395                                 "%d: got transaction with invalid extra_buffers_size %zd\n",
 396                                 alloc->pid, extra_buffers_size);
 397                 return ERR_PTR(-EINVAL);
 398         }
 399         if (is_async &&
 400             alloc->free_async_space < size + sizeof(struct binder_buffer)) {
 401                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 402                              "%d: binder_alloc_buf size %zd failed, no async space left\n",
 403                               alloc->pid, size);
 404                 return ERR_PTR(-ENOSPC);
 405         }
 406
 407         /* Pad 0-size buffers so they get assigned unique addresses */
 408         size = max(size, sizeof(void *));
 409
 410         while (n) {
 411                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 412                 BUG_ON(!buffer->free);
 413                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 414
 415                 if (size < buffer_size) {
 416                         best_fit = n;
 417                         n = n->rb_left;
 418                 } else if (size > buffer_size)
 419                         n = n->rb_right;
 420                 else {
 421                         best_fit = n;
 422                         break;
 423                 }
 424         }
 425         if (best_fit == NULL) {
 426                 size_t allocated_buffers = 0;
 427                 size_t largest_alloc_size = 0;
 428                 size_t total_alloc_size = 0;
 429                 size_t free_buffers = 0;
 430                 size_t largest_free_size = 0;
 431                 size_t total_free_size = 0;
 432
 433                 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 434                      n = rb_next(n)) {
 435                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 436                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 437                         allocated_buffers++;
 438                         total_alloc_size += buffer_size;
 439                         if (buffer_size > largest_alloc_size)
 440                                 largest_alloc_size = buffer_size;
 441                 }
 442                 for (n = rb_first(&alloc->free_buffers); n != NULL;
 443                      n = rb_next(n)) {
 444                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 445                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 446                         free_buffers++;
 447                         total_free_size += buffer_size;
 448                         if (buffer_size > largest_free_size)
 449                                 largest_free_size = buffer_size;
 450                 }
 451                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 452                                    "%d: binder_alloc_buf size %zd failed, no address space\n",
 453                                    alloc->pid, size);
 454                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 455                                    "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
 456                                    total_alloc_size, allocated_buffers,
 457                                    largest_alloc_size, total_free_size,
 458                                    free_buffers, largest_free_size);
 459                 return ERR_PTR(-ENOSPC);
 460         }
 461         if (n == NULL) {
 462                 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
 463                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 464         }
 465
 466         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 467                      "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
 468                       alloc->pid, size, buffer, buffer_size);
 469
 470         has_page_addr =
 471                 (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK);
 472         WARN_ON(n && buffer_size != size);
 473         end_page_addr =
 474                 (void *)PAGE_ALIGN((uintptr_t)buffer->data + size);
 475         if (end_page_addr > has_page_addr)
 476                 end_page_addr = has_page_addr;
 477         ret = binder_update_page_range(alloc, 1,
 478             (void *)PAGE_ALIGN((uintptr_t)buffer->data), end_page_addr);
 479         if (ret)
 480                 return ERR_PTR(ret);
 481
 482         if (buffer_size != size) {
 483                 struct binder_buffer *new_buffer;
 484
 485                 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 486                 if (!new_buffer) {
 487                         pr_err("%s: %d failed to alloc new buffer struct\n",
 488                                __func__, alloc->pid);
 489                         goto err_alloc_buf_struct_failed;
 490                 }
 491                 new_buffer->data = (u8 *)buffer->data + size;
 492                 list_add(&new_buffer->entry, &buffer->entry);
 493                 new_buffer->free = 1;
 494                 binder_insert_free_buffer(alloc, new_buffer);
 495         }
 496
 497         rb_erase(best_fit, &alloc->free_buffers);
 498         buffer->free = 0;
 499         buffer->allow_user_free = 0;
 500         binder_insert_allocated_buffer_locked(alloc, buffer);
 501         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 502                      "%d: binder_alloc_buf size %zd got %pK\n",
 503                       alloc->pid, size, buffer);
 504         buffer->data_size = data_size;
 505         buffer->offsets_size = offsets_size;
 506         buffer->async_transaction = is_async;
 507         buffer->extra_buffers_size = extra_buffers_size;
 508         if (is_async) {
 509                 alloc->free_async_space -= size + sizeof(struct binder_buffer);
 510                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 511                              "%d: binder_alloc_buf size %zd async free %zd\n",
 512                               alloc->pid, size, alloc->free_async_space);
 513         }
 514         return buffer;
 515
 516 err_alloc_buf_struct_failed:
 517         binder_update_page_range(alloc, 0,
 518                                  (void *)PAGE_ALIGN((uintptr_t)buffer->data),
 519                                  end_page_addr);
 520         return ERR_PTR(-ENOMEM);
 521 }
 522
 523 /**
 524  * binder_alloc_new_buf() - Allocate a new binder buffer
 525  * @alloc:              binder_alloc for this proc
 526  * @data_size:          size of user data buffer
 527  * @offsets_size:       user specified buffer offset
 528  * @extra_buffers_size: size of extra space for meta-data (eg, security context)
 529  * @is_async:           buffer for async transaction
 530  *
 531  * Allocate a new buffer given the requested sizes. Returns
 532  * the kernel version of the buffer pointer. The size allocated
 533  * is the sum of the three given sizes (each rounded up to
 534  * pointer-sized boundary)
 535  *
 536  * Return:      The allocated buffer or %NULL if error
 537  */
 538 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 539                                            size_t data_size,
 540                                            size_t offsets_size,
 541                                            size_t extra_buffers_size,
 542                                            int is_async)
 543 {
 544         struct binder_buffer *buffer;
 545
 546         mutex_lock(&alloc->mutex);
 547         buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
 548                                              extra_buffers_size, is_async);
 549         mutex_unlock(&alloc->mutex);
 550         return buffer;
 551 }
 552
 553 static void *buffer_start_page(struct binder_buffer *buffer)
 554 {
 555         return (void *)((uintptr_t)buffer->data & PAGE_MASK);
 556 }
 557
 558 static void *prev_buffer_end_page(struct binder_buffer *buffer)
 559 {
 560         return (void *)(((uintptr_t)(buffer->data) - 1) & PAGE_MASK);
 561 }
 562
 563 static void binder_delete_free_buffer(struct binder_alloc *alloc,
 564                                       struct binder_buffer *buffer)
 565 {
 566         struct binder_buffer *prev, *next = NULL;
 567         bool to_free = true;
 568         BUG_ON(alloc->buffers.next == &buffer->entry);
 569         prev = binder_buffer_prev(buffer);
 570         BUG_ON(!prev->free);
 571         if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
 572                 to_free = false;
 573                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 574                                    "%d: merge free, buffer %pK share page with %pK\n",
 575                                    alloc->pid, buffer->data, prev->data);
 576         }
 577
 578         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 579                 next = binder_buffer_next(buffer);
 580                 if (buffer_start_page(next) == buffer_start_page(buffer)) {
 581                         to_free = false;
 582                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 583                                            "%d: merge free, buffer %pK share page with %pK\n",
 584                                            alloc->pid,
 585                                            buffer->data,
 586                                            next->data);
 587                 }
 588         }
 589
 590         if (PAGE_ALIGNED(buffer->data)) {
 591                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 592                                    "%d: merge free, buffer start %pK is page aligned\n",
 593                                    alloc->pid, buffer->data);
 594                 to_free = false;
 595         }
 596
 597         if (to_free) {
 598                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 599                                    "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
 600                                    alloc->pid, buffer->data,
 601                                    prev->data, next ? next->data : NULL);
 602                 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
 603                                          buffer_start_page(buffer) + PAGE_SIZE);
 604         }
 605         list_del(&buffer->entry);
 606         kfree(buffer);
 607 }
 608
 609 static void binder_free_buf_locked(struct binder_alloc *alloc,
 610                                    struct binder_buffer *buffer)
 611 {
 612         size_t size, buffer_size;
 613
 614         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 615
 616         size = ALIGN(buffer->data_size, sizeof(void *)) +
 617                 ALIGN(buffer->offsets_size, sizeof(void *)) +
 618                 ALIGN(buffer->extra_buffers_size, sizeof(void *));
 619
 620         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 621                      "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
 622                       alloc->pid, buffer, size, buffer_size);
 623
 624         BUG_ON(buffer->free);
 625         BUG_ON(size > buffer_size);
 626         BUG_ON(buffer->transaction != NULL);
 627         BUG_ON(buffer->data < alloc->buffer);
 628         BUG_ON(buffer->data > alloc->buffer + alloc->buffer_size);
 629
 630         if (buffer->async_transaction) {
 631                 alloc->free_async_space += size + sizeof(struct binder_buffer);
 632
 633                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 634                              "%d: binder_free_buf size %zd async free %zd\n",
 635                               alloc->pid, size, alloc->free_async_space);
 636         }
 637
 638         binder_update_page_range(alloc, 0,
 639                 (void *)PAGE_ALIGN((uintptr_t)buffer->data),
 640                 (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK));
 641
 642         rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
 643         buffer->free = 1;
 644         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 645                 struct binder_buffer *next = binder_buffer_next(buffer);
 646
 647                 if (next->free) {
 648                         rb_erase(&next->rb_node, &alloc->free_buffers);
 649                         binder_delete_free_buffer(alloc, next);
 650                 }
 651         }
 652         if (alloc->buffers.next != &buffer->entry) {
 653                 struct binder_buffer *prev = binder_buffer_prev(buffer);
 654
 655                 if (prev->free) {
 656                         binder_delete_free_buffer(alloc, buffer);
 657                         rb_erase(&prev->rb_node, &alloc->free_buffers);
 658                         buffer = prev;
 659                 }
 660         }
 661         binder_insert_free_buffer(alloc, buffer);
 662 }
 663
 664 /**
 665  * binder_alloc_free_buf() - free a binder buffer
 666  * @alloc:      binder_alloc for this proc
 667  * @buffer:     kernel pointer to buffer
 668  *
 669  * Free the buffer allocated via binder_alloc_new_buffer()
 670  */
 671 void binder_alloc_free_buf(struct binder_alloc *alloc,
 672                             struct binder_buffer *buffer)
 673 {
 674         mutex_lock(&alloc->mutex);
 675         binder_free_buf_locked(alloc, buffer);
 676         mutex_unlock(&alloc->mutex);
 677 }
 678
 679 /**
 680  * binder_alloc_mmap_handler() - map virtual address space for proc
 681  * @alloc:      alloc structure for this proc
 682  * @vma:        vma passed to mmap()
 683  *
 684  * Called by binder_mmap() to initialize the space specified in
 685  * vma for allocating binder buffers
 686  *
 687  * Return:
 688  *      0 = success
 689  *      -EBUSY = address space already mapped
 690  *      -ENOMEM = failed to map memory to given address space
 691  */
 692 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 693                               struct vm_area_struct *vma)
 694 {
 695         int ret;
 696         struct vm_struct *area;
 697         const char *failure_string;
 698         struct binder_buffer *buffer;
 699
 700         mutex_lock(&binder_alloc_mmap_lock);
 701         if (alloc->buffer) {
 702                 ret = -EBUSY;
 703                 failure_string = "already mapped";
 704                 goto err_already_mapped;
 705         }
 706
 707         area = get_vm_area(vma->vm_end - vma->vm_start, VM_ALLOC);
 708         if (area == NULL) {
 709                 ret = -ENOMEM;
 710                 failure_string = "get_vm_area";
 711                 goto err_get_vm_area_failed;
 712         }
 713         alloc->buffer = area->addr;
 714         alloc->user_buffer_offset =
 715                 vma->vm_start - (uintptr_t)alloc->buffer;
 716         mutex_unlock(&binder_alloc_mmap_lock);
 717
 718 #ifdef CONFIG_CPU_CACHE_VIPT
 719         if (cache_is_vipt_aliasing()) {
 720                 while (CACHE_COLOUR(
 721                                 (vma->vm_start ^ (uint32_t)alloc->buffer))) {
 722                         pr_info("%s: %d %lx-%lx maps %pK bad alignment\n",
 723                                 __func__, alloc->pid, vma->vm_start,
 724                                 vma->vm_end, alloc->buffer);
 725                         vma->vm_start += PAGE_SIZE;
 726                 }
 727         }
 728 #endif
 729         alloc->pages = kcalloc((vma->vm_end - vma->vm_start) / PAGE_SIZE,
 730                                sizeof(alloc->pages[0]),
 731                                GFP_KERNEL);
 732         if (alloc->pages == NULL) {
 733                 ret = -ENOMEM;
 734                 failure_string = "alloc page array";
 735                 goto err_alloc_pages_failed;
 736         }
 737         alloc->buffer_size = vma->vm_end - vma->vm_start;
 738
 739         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 740         if (!buffer) {
 741                 ret = -ENOMEM;
 742                 failure_string = "alloc buffer struct";
 743                 goto err_alloc_buf_struct_failed;
 744         }
 745
 746         buffer->data = alloc->buffer;
 747         list_add(&buffer->entry, &alloc->buffers);
 748         buffer->free = 1;
 749         binder_insert_free_buffer(alloc, buffer);
 750         alloc->free_async_space = alloc->buffer_size / 2;
 751         binder_alloc_set_vma(alloc, vma);
 752         mmgrab(alloc->vma_vm_mm);
 753
 754         return 0;
 755
 756 err_alloc_buf_struct_failed:
 757         kfree(alloc->pages);
 758         alloc->pages = NULL;
 759 err_alloc_pages_failed:
 760         mutex_lock(&binder_alloc_mmap_lock);
 761         vfree(alloc->buffer);
 762         alloc->buffer = NULL;
 763 err_get_vm_area_failed:
 764 err_already_mapped:
 765         mutex_unlock(&binder_alloc_mmap_lock);
 766         binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 767                            "%s: %d %lx-%lx %s failed %d\n", __func__,
 768                            alloc->pid, vma->vm_start, vma->vm_end,
 769                            failure_string, ret);
 770         return ret;
 771 }
 772
 773
 774 void binder_alloc_deferred_release(struct binder_alloc *alloc)
 775 {
 776         struct rb_node *n;
 777         int buffers, page_count;
 778         struct binder_buffer *buffer;
 779
 780         buffers = 0;
 781         mutex_lock(&alloc->mutex);
 782         BUG_ON(alloc->vma);
 783
 784         while ((n = rb_first(&alloc->allocated_buffers))) {
 785                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 786
 787                 /* Transaction should already have been freed */
 788                 BUG_ON(buffer->transaction);
 789
 790                 binder_free_buf_locked(alloc, buffer);
 791                 buffers++;
 792         }
 793
 794         while (!list_empty(&alloc->buffers)) {
 795                 buffer = list_first_entry(&alloc->buffers,
 796                                           struct binder_buffer, entry);
 797                 WARN_ON(!buffer->free);
 798
 799                 list_del(&buffer->entry);
 800                 WARN_ON_ONCE(!list_empty(&alloc->buffers));
 801                 kfree(buffer);
 802         }
 803
 804         page_count = 0;
 805         if (alloc->pages) {
 806                 int i;
 807
 808                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 809                         void *page_addr;
 810                         bool on_lru;
 811
 812                         if (!alloc->pages[i].page_ptr)
 813                                 continue;
 814
 815                         on_lru = list_lru_del(&binder_alloc_lru,
 816                                               &alloc->pages[i].lru);
 817                         page_addr = alloc->buffer + i * PAGE_SIZE;
 818                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 819                                      "%s: %d: page %d at %pK %s\n",
 820                                      __func__, alloc->pid, i, page_addr,
 821                                      on_lru ? "on lru" : "active");
 822                         unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
 823                         __free_page(alloc->pages[i].page_ptr);
 824                         page_count++;
 825                 }
 826                 kfree(alloc->pages);
 827                 vfree(alloc->buffer);
 828         }
 829         mutex_unlock(&alloc->mutex);
 830         if (alloc->vma_vm_mm)
 831                 mmdrop(alloc->vma_vm_mm);
 832
 833         binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
 834                      "%s: %d buffers %d, pages %d\n",
 835                      __func__, alloc->pid, buffers, page_count);
 836 }
 837
 838 static void print_binder_buffer(struct seq_file *m, const char *prefix,
 839                                 struct binder_buffer *buffer)
 840 {
 841         seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
 842                    prefix, buffer->debug_id, buffer->data,
 843                    buffer->data_size, buffer->offsets_size,
 844                    buffer->extra_buffers_size,
 845                    buffer->transaction ? "active" : "delivered");
 846 }
 847
 848 /**
 849  * binder_alloc_print_allocated() - print buffer info
 850  * @m:     seq_file for output via seq_printf()
 851  * @alloc: binder_alloc for this proc
 852  *
 853  * Prints information about every buffer associated with
 854  * the binder_alloc state to the given seq_file
 855  */
 856 void binder_alloc_print_allocated(struct seq_file *m,
 857                                   struct binder_alloc *alloc)
 858 {
 859         struct rb_node *n;
 860
 861         mutex_lock(&alloc->mutex);
 862         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 863                 print_binder_buffer(m, "  buffer",
 864                                     rb_entry(n, struct binder_buffer, rb_node));
 865         mutex_unlock(&alloc->mutex);
 866 }
 867
 868 /**
 869  * binder_alloc_print_pages() - print page usage
 870  * @m:     seq_file for output via seq_printf()
 871  * @alloc: binder_alloc for this proc
 872  */
 873 void binder_alloc_print_pages(struct seq_file *m,
 874                               struct binder_alloc *alloc)
 875 {
 876         struct binder_lru_page *page;
 877         int i;
 878         int active = 0;
 879         int lru = 0;
 880         int free = 0;
 881
 882         mutex_lock(&alloc->mutex);
 883         for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 884                 page = &alloc->pages[i];
 885                 if (!page->page_ptr)
 886                         free++;
 887                 else if (list_empty(&page->lru))
 888                         active++;
 889                 else
 890                         lru++;
 891         }
 892         mutex_unlock(&alloc->mutex);
 893         seq_printf(m, "  pages: %d:%d:%d\n", active, lru, free);
 894         seq_printf(m, "  pages high watermark: %zu\n", alloc->pages_high);
 895 }
 896
 897 /**
 898  * binder_alloc_get_allocated_count() - return count of buffers
 899  * @alloc: binder_alloc for this proc
 900  *
 901  * Return: count of allocated buffers
 902  */
 903 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
 904 {
 905         struct rb_node *n;
 906         int count = 0;
 907
 908         mutex_lock(&alloc->mutex);
 909         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 910                 count++;
 911         mutex_unlock(&alloc->mutex);
 912         return count;
 913 }
 914
 915
 916 /**
 917  * binder_alloc_vma_close() - invalidate address space
 918  * @alloc: binder_alloc for this proc
 919  *
 920  * Called from binder_vma_close() when releasing address space.
 921  * Clears alloc->vma to prevent new incoming transactions from
 922  * allocating more buffers.
 923  */
 924 void binder_alloc_vma_close(struct binder_alloc *alloc)
 925 {
 926         binder_alloc_set_vma(alloc, NULL);
 927 }
 928
 929 /**
 930  * binder_alloc_free_page() - shrinker callback to free pages
 931  * @item:   item to free
 932  * @lock:   lock protecting the item
 933  * @cb_arg: callback argument
 934  *
 935  * Called from list_lru_walk() in binder_shrink_scan() to free
 936  * up pages when the system is under memory pressure.
 937  */
 938 enum lru_status binder_alloc_free_page(struct list_head *item,
 939                                        struct list_lru_one *lru,
 940                                        spinlock_t *lock,
 941                                        void *cb_arg)
 942         __must_hold(lock)
 943 {
 944         struct mm_struct *mm = NULL;
 945         struct binder_lru_page *page = container_of(item,
 946                                                     struct binder_lru_page,
 947                                                     lru);
 948         struct binder_alloc *alloc;
 949         uintptr_t page_addr;
 950         size_t index;
 951         struct vm_area_struct *vma;
 952
 953         alloc = page->alloc;
 954         if (!mutex_trylock(&alloc->mutex))
 955                 goto err_get_alloc_mutex_failed;
 956
 957         if (!page->page_ptr)
 958                 goto err_page_already_freed;
 959
 960         index = page - alloc->pages;
 961         page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
 962         vma = binder_alloc_get_vma(alloc);
 963         if (vma) {
 964                 if (!mmget_not_zero(alloc->vma_vm_mm))
 965                         goto err_mmget;
 966                 mm = alloc->vma_vm_mm;
 967                 if (!down_write_trylock(&mm->mmap_sem))
 968                         goto err_down_write_mmap_sem_failed;
 969         }
 970
 971         list_lru_isolate(lru, item);
 972         spin_unlock(lock);
 973
 974         if (vma) {
 975                 trace_binder_unmap_user_start(alloc, index);
 976
 977                 zap_page_range(vma,
 978                                page_addr + alloc->user_buffer_offset,
 979                                PAGE_SIZE);
 980
 981                 trace_binder_unmap_user_end(alloc, index);
 982
 983                 up_write(&mm->mmap_sem);
 984                 mmput(mm);
 985         }
 986
 987         trace_binder_unmap_kernel_start(alloc, index);
 988
 989         unmap_kernel_range(page_addr, PAGE_SIZE);
 990         __free_page(page->page_ptr);
 991         page->page_ptr = NULL;
 992
 993         trace_binder_unmap_kernel_end(alloc, index);
 994
 995         spin_lock(lock);
 996         mutex_unlock(&alloc->mutex);
 997         return LRU_REMOVED_RETRY;
 998
 999 err_down_write_mmap_sem_failed:
1000         mmput_async(mm);
1001 err_mmget:
1002 err_page_already_freed:
1003         mutex_unlock(&alloc->mutex);
1004 err_get_alloc_mutex_failed:
1005         return LRU_SKIP;
1006 }
1007
1008 static unsigned long
1009 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
1010 {
1011         unsigned long ret = list_lru_count(&binder_alloc_lru);
1012         return ret;
1013 }
1014
1015 static unsigned long
1016 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1017 {
1018         unsigned long ret;
1019
1020         ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
1021                             NULL, sc->nr_to_scan);
1022         return ret;
1023 }
1024
1025 static struct shrinker binder_shrinker = {
1026         .count_objects = binder_shrink_count,
1027         .scan_objects = binder_shrink_scan,
1028         .seeks = DEFAULT_SEEKS,
1029 };
1030
1031 /**
1032  * binder_alloc_init() - called by binder_open() for per-proc initialization
1033  * @alloc: binder_alloc for this proc
1034  *
1035  * Called from binder_open() to initialize binder_alloc fields for
1036  * new binder proc
1037  */
1038 void binder_alloc_init(struct binder_alloc *alloc)
1039 {
1040         alloc->pid = current->group_leader->pid;
1041         mutex_init(&alloc->mutex);
1042         INIT_LIST_HEAD(&alloc->buffers);
1043 }
1044
1045 int binder_alloc_shrinker_init(void)
1046 {
1047         int ret = list_lru_init(&binder_alloc_lru);
1048
1049         if (ret == 0) {
1050                 ret = register_shrinker(&binder_shrinker);
1051                 if (ret)
1052                         list_lru_destroy(&binder_alloc_lru);
1053         }
1054         return ret;
1055 }