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 twice
 155                          */
 156                         if (buffer->free_in_progress) {
 157                                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 158                                                    "%d:%d FREE_BUFFER u%016llx user freed buffer twice\n",
 159                                                    alloc->pid, current->pid,
 160                                                    (u64)user_ptr);
 161                                 return NULL;
 162                         }
 163                         buffer->free_in_progress = 1;
 164                         return buffer;
 165                 }
 166         }
 167         return NULL;
 168 }
 169
 170 /**
 171  * binder_alloc_buffer_lookup() - get buffer given user ptr
 172  * @alloc:      binder_alloc for this proc
 173  * @user_ptr:   User pointer to buffer data
 174  *
 175  * Validate userspace pointer to buffer data and return buffer corresponding to
 176  * that user pointer. Search the rb tree for buffer that matches user data
 177  * pointer.
 178  *
 179  * Return:      Pointer to buffer or NULL
 180  */
 181 struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
 182                                                    uintptr_t user_ptr)
 183 {
 184         struct binder_buffer *buffer;
 185
 186         mutex_lock(&alloc->mutex);
 187         buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
 188         mutex_unlock(&alloc->mutex);
 189         return buffer;
 190 }
 191
 192 static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
 193                                     void *start, void *end)
 194 {
 195         void *page_addr;
 196         unsigned long user_page_addr;
 197         struct binder_lru_page *page;
 198         struct vm_area_struct *vma = NULL;
 199         struct mm_struct *mm = NULL;
 200         bool need_mm = false;
 201
 202         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 203                      "%d: %s pages %pK-%pK\n", alloc->pid,
 204                      allocate ? "allocate" : "free", start, end);
 205
 206         if (end <= start)
 207                 return 0;
 208
 209         trace_binder_update_page_range(alloc, allocate, start, end);
 210
 211         if (allocate == 0)
 212                 goto free_range;
 213
 214         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 215                 page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
 216                 if (!page->page_ptr) {
 217                         need_mm = true;
 218                         break;
 219                 }
 220         }
 221
 222         if (need_mm && mmget_not_zero(alloc->vma_vm_mm))
 223                 mm = alloc->vma_vm_mm;
 224
 225         if (mm) {
 226                 down_read(&mm->mmap_sem);
 227                 vma = alloc->vma;
 228         }
 229
 230         if (!vma && need_mm) {
 231                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 232                                    "%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
 233                                    alloc->pid);
 234                 goto err_no_vma;
 235         }
 236
 237         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 238                 int ret;
 239                 bool on_lru;
 240                 size_t index;
 241
 242                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 243                 page = &alloc->pages[index];
 244
 245                 if (page->page_ptr) {
 246                         trace_binder_alloc_lru_start(alloc, index);
 247
 248                         on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
 249                         WARN_ON(!on_lru);
 250
 251                         trace_binder_alloc_lru_end(alloc, index);
 252                         continue;
 253                 }
 254
 255                 if (WARN_ON(!vma))
 256                         goto err_page_ptr_cleared;
 257
 258                 trace_binder_alloc_page_start(alloc, index);
 259                 page->page_ptr = alloc_page(GFP_KERNEL |
 260                                             __GFP_HIGHMEM |
 261                                             __GFP_ZERO);
 262                 if (!page->page_ptr) {
 263                         pr_err("%d: binder_alloc_buf failed for page at %pK\n",
 264                                 alloc->pid, page_addr);
 265                         goto err_alloc_page_failed;
 266                 }
 267                 page->alloc = alloc;
 268                 INIT_LIST_HEAD(&page->lru);
 269
 270                 ret = map_kernel_range_noflush((unsigned long)page_addr,
 271                                                PAGE_SIZE, PAGE_KERNEL,
 272                                                &page->page_ptr);
 273                 flush_cache_vmap((unsigned long)page_addr,
 274                                 (unsigned long)page_addr + PAGE_SIZE);
 275                 if (ret != 1) {
 276                         pr_err("%d: binder_alloc_buf failed to map page at %pK in kernel\n",
 277                                alloc->pid, page_addr);
 278                         goto err_map_kernel_failed;
 279                 }
 280                 user_page_addr =
 281                         (uintptr_t)page_addr + alloc->user_buffer_offset;
 282                 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
 283                 if (ret) {
 284                         pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
 285                                alloc->pid, user_page_addr);
 286                         goto err_vm_insert_page_failed;
 287                 }
 288
 289                 if (index + 1 > alloc->pages_high)
 290                         alloc->pages_high = index + 1;
 291
 292                 trace_binder_alloc_page_end(alloc, index);
 293                 /* vm_insert_page does not seem to increment the refcount */
 294         }
 295         if (mm) {
 296                 up_read(&mm->mmap_sem);
 297                 mmput(mm);
 298         }
 299         return 0;
 300
 301 free_range:
 302         for (page_addr = end - PAGE_SIZE; page_addr >= start;
 303              page_addr -= PAGE_SIZE) {
 304                 bool ret;
 305                 size_t index;
 306
 307                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 308                 page = &alloc->pages[index];
 309
 310                 trace_binder_free_lru_start(alloc, index);
 311
 312                 ret = list_lru_add(&binder_alloc_lru, &page->lru);
 313                 WARN_ON(!ret);
 314
 315                 trace_binder_free_lru_end(alloc, index);
 316                 continue;
 317
 318 err_vm_insert_page_failed:
 319                 unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
 320 err_map_kernel_failed:
 321                 __free_page(page->page_ptr);
 322                 page->page_ptr = NULL;
 323 err_alloc_page_failed:
 324 err_page_ptr_cleared:
 325                 ;
 326         }
 327 err_no_vma:
 328         if (mm) {
 329                 up_read(&mm->mmap_sem);
 330                 mmput(mm);
 331         }
 332         return vma ? -ENOMEM : -ESRCH;
 333 }
 334
 335
 336 static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
 337                 struct vm_area_struct *vma)
 338 {
 339         if (vma)
 340                 alloc->vma_vm_mm = vma->vm_mm;
 341         /*
 342          * If we see alloc->vma is not NULL, buffer data structures set up
 343          * completely. Look at smp_rmb side binder_alloc_get_vma.
 344          * We also want to guarantee new alloc->vma_vm_mm is always visible
 345          * if alloc->vma is set.
 346          */
 347         smp_wmb();
 348         alloc->vma = vma;
 349 }
 350
 351 static inline struct vm_area_struct *binder_alloc_get_vma(
 352                 struct binder_alloc *alloc)
 353 {
 354         struct vm_area_struct *vma = NULL;
 355
 356         if (alloc->vma) {
 357                 /* Look at description in binder_alloc_set_vma */
 358                 smp_rmb();
 359                 vma = alloc->vma;
 360         }
 361         return vma;
 362 }
 363
 364 static struct binder_buffer *binder_alloc_new_buf_locked(
 365                                 struct binder_alloc *alloc,
 366                                 size_t data_size,
 367                                 size_t offsets_size,
 368                                 size_t extra_buffers_size,
 369                                 int is_async)
 370 {
 371         struct rb_node *n = alloc->free_buffers.rb_node;
 372         struct binder_buffer *buffer;
 373         size_t buffer_size;
 374         struct rb_node *best_fit = NULL;
 375         void *has_page_addr;
 376         void *end_page_addr;
 377         size_t size, data_offsets_size;
 378         int ret;
 379
 380         if (!binder_alloc_get_vma(alloc)) {
 381                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 382                                    "%d: binder_alloc_buf, no vma\n",
 383                                    alloc->pid);
 384                 return ERR_PTR(-ESRCH);
 385         }
 386
 387         data_offsets_size = ALIGN(data_size, sizeof(void *)) +
 388                 ALIGN(offsets_size, sizeof(void *));
 389
 390         if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
 391                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 392                                 "%d: got transaction with invalid size %zd-%zd\n",
 393                                 alloc->pid, data_size, offsets_size);
 394                 return ERR_PTR(-EINVAL);
 395         }
 396         size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
 397         if (size < data_offsets_size || size < extra_buffers_size) {
 398                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 399                                 "%d: got transaction with invalid extra_buffers_size %zd\n",
 400                                 alloc->pid, extra_buffers_size);
 401                 return ERR_PTR(-EINVAL);
 402         }
 403         if (is_async &&
 404             alloc->free_async_space < size + sizeof(struct binder_buffer)) {
 405                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 406                              "%d: binder_alloc_buf size %zd failed, no async space left\n",
 407                               alloc->pid, size);
 408                 return ERR_PTR(-ENOSPC);
 409         }
 410
 411         /* Pad 0-size buffers so they get assigned unique addresses */
 412         size = max(size, sizeof(void *));
 413
 414         while (n) {
 415                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 416                 BUG_ON(!buffer->free);
 417                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 418
 419                 if (size < buffer_size) {
 420                         best_fit = n;
 421                         n = n->rb_left;
 422                 } else if (size > buffer_size)
 423                         n = n->rb_right;
 424                 else {
 425                         best_fit = n;
 426                         break;
 427                 }
 428         }
 429         if (best_fit == NULL) {
 430                 size_t allocated_buffers = 0;
 431                 size_t largest_alloc_size = 0;
 432                 size_t total_alloc_size = 0;
 433                 size_t free_buffers = 0;
 434                 size_t largest_free_size = 0;
 435                 size_t total_free_size = 0;
 436
 437                 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 438                      n = rb_next(n)) {
 439                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 440                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 441                         allocated_buffers++;
 442                         total_alloc_size += buffer_size;
 443                         if (buffer_size > largest_alloc_size)
 444                                 largest_alloc_size = buffer_size;
 445                 }
 446                 for (n = rb_first(&alloc->free_buffers); n != NULL;
 447                      n = rb_next(n)) {
 448                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 449                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 450                         free_buffers++;
 451                         total_free_size += buffer_size;
 452                         if (buffer_size > largest_free_size)
 453                                 largest_free_size = buffer_size;
 454                 }
 455                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 456                                    "%d: binder_alloc_buf size %zd failed, no address space\n",
 457                                    alloc->pid, size);
 458                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 459                                    "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
 460                                    total_alloc_size, allocated_buffers,
 461                                    largest_alloc_size, total_free_size,
 462                                    free_buffers, largest_free_size);
 463                 return ERR_PTR(-ENOSPC);
 464         }
 465         if (n == NULL) {
 466                 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
 467                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 468         }
 469
 470         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 471                      "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
 472                       alloc->pid, size, buffer, buffer_size);
 473
 474         has_page_addr =
 475                 (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK);
 476         WARN_ON(n && buffer_size != size);
 477         end_page_addr =
 478                 (void *)PAGE_ALIGN((uintptr_t)buffer->data + size);
 479         if (end_page_addr > has_page_addr)
 480                 end_page_addr = has_page_addr;
 481         ret = binder_update_page_range(alloc, 1,
 482             (void *)PAGE_ALIGN((uintptr_t)buffer->data), end_page_addr);
 483         if (ret)
 484                 return ERR_PTR(ret);
 485
 486         if (buffer_size != size) {
 487                 struct binder_buffer *new_buffer;
 488
 489                 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 490                 if (!new_buffer) {
 491                         pr_err("%s: %d failed to alloc new buffer struct\n",
 492                                __func__, alloc->pid);
 493                         goto err_alloc_buf_struct_failed;
 494                 }
 495                 new_buffer->data = (u8 *)buffer->data + size;
 496                 list_add(&new_buffer->entry, &buffer->entry);
 497                 new_buffer->free = 1;
 498                 binder_insert_free_buffer(alloc, new_buffer);
 499         }
 500
 501         rb_erase(best_fit, &alloc->free_buffers);
 502         buffer->free = 0;
 503         buffer->free_in_progress = 0;
 504         binder_insert_allocated_buffer_locked(alloc, buffer);
 505         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 506                      "%d: binder_alloc_buf size %zd got %pK\n",
 507                       alloc->pid, size, buffer);
 508         buffer->data_size = data_size;
 509         buffer->offsets_size = offsets_size;
 510         buffer->async_transaction = is_async;
 511         buffer->extra_buffers_size = extra_buffers_size;
 512         if (is_async) {
 513                 alloc->free_async_space -= size + sizeof(struct binder_buffer);
 514                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 515                              "%d: binder_alloc_buf size %zd async free %zd\n",
 516                               alloc->pid, size, alloc->free_async_space);
 517         }
 518         return buffer;
 519
 520 err_alloc_buf_struct_failed:
 521         binder_update_page_range(alloc, 0,
 522                                  (void *)PAGE_ALIGN((uintptr_t)buffer->data),
 523                                  end_page_addr);
 524         return ERR_PTR(-ENOMEM);
 525 }
 526
 527 /**
 528  * binder_alloc_new_buf() - Allocate a new binder buffer
 529  * @alloc:              binder_alloc for this proc
 530  * @data_size:          size of user data buffer
 531  * @offsets_size:       user specified buffer offset
 532  * @extra_buffers_size: size of extra space for meta-data (eg, security context)
 533  * @is_async:           buffer for async transaction
 534  *
 535  * Allocate a new buffer given the requested sizes. Returns
 536  * the kernel version of the buffer pointer. The size allocated
 537  * is the sum of the three given sizes (each rounded up to
 538  * pointer-sized boundary)
 539  *
 540  * Return:      The allocated buffer or %NULL if error
 541  */
 542 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 543                                            size_t data_size,
 544                                            size_t offsets_size,
 545                                            size_t extra_buffers_size,
 546                                            int is_async)
 547 {
 548         struct binder_buffer *buffer;
 549
 550         mutex_lock(&alloc->mutex);
 551         buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
 552                                              extra_buffers_size, is_async);
 553         mutex_unlock(&alloc->mutex);
 554         return buffer;
 555 }
 556
 557 static void *buffer_start_page(struct binder_buffer *buffer)
 558 {
 559         return (void *)((uintptr_t)buffer->data & PAGE_MASK);
 560 }
 561
 562 static void *prev_buffer_end_page(struct binder_buffer *buffer)
 563 {
 564         return (void *)(((uintptr_t)(buffer->data) - 1) & PAGE_MASK);
 565 }
 566
 567 static void binder_delete_free_buffer(struct binder_alloc *alloc,
 568                                       struct binder_buffer *buffer)
 569 {
 570         struct binder_buffer *prev, *next = NULL;
 571         bool to_free = true;
 572         BUG_ON(alloc->buffers.next == &buffer->entry);
 573         prev = binder_buffer_prev(buffer);
 574         BUG_ON(!prev->free);
 575         if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
 576                 to_free = false;
 577                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 578                                    "%d: merge free, buffer %pK share page with %pK\n",
 579                                    alloc->pid, buffer->data, prev->data);
 580         }
 581
 582         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 583                 next = binder_buffer_next(buffer);
 584                 if (buffer_start_page(next) == buffer_start_page(buffer)) {
 585                         to_free = false;
 586                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 587                                            "%d: merge free, buffer %pK share page with %pK\n",
 588                                            alloc->pid,
 589                                            buffer->data,
 590                                            next->data);
 591                 }
 592         }
 593
 594         if (PAGE_ALIGNED(buffer->data)) {
 595                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 596                                    "%d: merge free, buffer start %pK is page aligned\n",
 597                                    alloc->pid, buffer->data);
 598                 to_free = false;
 599         }
 600
 601         if (to_free) {
 602                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 603                                    "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
 604                                    alloc->pid, buffer->data,
 605                                    prev->data, next ? next->data : NULL);
 606                 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
 607                                          buffer_start_page(buffer) + PAGE_SIZE);
 608         }
 609         list_del(&buffer->entry);
 610         kfree(buffer);
 611 }
 612
 613 static void binder_free_buf_locked(struct binder_alloc *alloc,
 614                                    struct binder_buffer *buffer)
 615 {
 616         size_t size, buffer_size;
 617
 618         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 619
 620         size = ALIGN(buffer->data_size, sizeof(void *)) +
 621                 ALIGN(buffer->offsets_size, sizeof(void *)) +
 622                 ALIGN(buffer->extra_buffers_size, sizeof(void *));
 623
 624         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 625                      "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
 626                       alloc->pid, buffer, size, buffer_size);
 627
 628         BUG_ON(buffer->free);
 629         BUG_ON(size > buffer_size);
 630         BUG_ON(buffer->transaction != NULL);
 631         BUG_ON(buffer->data < alloc->buffer);
 632         BUG_ON(buffer->data > alloc->buffer + alloc->buffer_size);
 633
 634         if (buffer->async_transaction) {
 635                 alloc->free_async_space += size + sizeof(struct binder_buffer);
 636
 637                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 638                              "%d: binder_free_buf size %zd async free %zd\n",
 639                               alloc->pid, size, alloc->free_async_space);
 640         }
 641
 642         binder_update_page_range(alloc, 0,
 643                 (void *)PAGE_ALIGN((uintptr_t)buffer->data),
 644                 (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK));
 645
 646         rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
 647         buffer->free = 1;
 648         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 649                 struct binder_buffer *next = binder_buffer_next(buffer);
 650
 651                 if (next->free) {
 652                         rb_erase(&next->rb_node, &alloc->free_buffers);
 653                         binder_delete_free_buffer(alloc, next);
 654                 }
 655         }
 656         if (alloc->buffers.next != &buffer->entry) {
 657                 struct binder_buffer *prev = binder_buffer_prev(buffer);
 658
 659                 if (prev->free) {
 660                         binder_delete_free_buffer(alloc, buffer);
 661                         rb_erase(&prev->rb_node, &alloc->free_buffers);
 662                         buffer = prev;
 663                 }
 664         }
 665         binder_insert_free_buffer(alloc, buffer);
 666 }
 667
 668 /**
 669  * binder_alloc_free_buf() - free a binder buffer
 670  * @alloc:      binder_alloc for this proc
 671  * @buffer:     kernel pointer to buffer
 672  *
 673  * Free the buffer allocated via binder_alloc_new_buffer()
 674  */
 675 void binder_alloc_free_buf(struct binder_alloc *alloc,
 676                             struct binder_buffer *buffer)
 677 {
 678         mutex_lock(&alloc->mutex);
 679         binder_free_buf_locked(alloc, buffer);
 680         mutex_unlock(&alloc->mutex);
 681 }
 682
 683 /**
 684  * binder_alloc_mmap_handler() - map virtual address space for proc
 685  * @alloc:      alloc structure for this proc
 686  * @vma:        vma passed to mmap()
 687  *
 688  * Called by binder_mmap() to initialize the space specified in
 689  * vma for allocating binder buffers
 690  *
 691  * Return:
 692  *      0 = success
 693  *      -EBUSY = address space already mapped
 694  *      -ENOMEM = failed to map memory to given address space
 695  */
 696 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 697                               struct vm_area_struct *vma)
 698 {
 699         int ret;
 700         struct vm_struct *area;
 701         const char *failure_string;
 702         struct binder_buffer *buffer;
 703
 704         mutex_lock(&binder_alloc_mmap_lock);
 705         if (alloc->buffer) {
 706                 ret = -EBUSY;
 707                 failure_string = "already mapped";
 708                 goto err_already_mapped;
 709         }
 710
 711         area = get_vm_area(vma->vm_end - vma->vm_start, VM_ALLOC);
 712         if (area == NULL) {
 713                 ret = -ENOMEM;
 714                 failure_string = "get_vm_area";
 715                 goto err_get_vm_area_failed;
 716         }
 717         alloc->buffer = area->addr;
 718         alloc->user_buffer_offset =
 719                 vma->vm_start - (uintptr_t)alloc->buffer;
 720         mutex_unlock(&binder_alloc_mmap_lock);
 721
 722 #ifdef CONFIG_CPU_CACHE_VIPT
 723         if (cache_is_vipt_aliasing()) {
 724                 while (CACHE_COLOUR(
 725                                 (vma->vm_start ^ (uint32_t)alloc->buffer))) {
 726                         pr_info("%s: %d %lx-%lx maps %pK bad alignment\n",
 727                                 __func__, alloc->pid, vma->vm_start,
 728                                 vma->vm_end, alloc->buffer);
 729                         vma->vm_start += PAGE_SIZE;
 730                 }
 731         }
 732 #endif
 733         alloc->pages = kcalloc((vma->vm_end - vma->vm_start) / PAGE_SIZE,
 734                                sizeof(alloc->pages[0]),
 735                                GFP_KERNEL);
 736         if (alloc->pages == NULL) {
 737                 ret = -ENOMEM;
 738                 failure_string = "alloc page array";
 739                 goto err_alloc_pages_failed;
 740         }
 741         alloc->buffer_size = vma->vm_end - vma->vm_start;
 742
 743         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 744         if (!buffer) {
 745                 ret = -ENOMEM;
 746                 failure_string = "alloc buffer struct";
 747                 goto err_alloc_buf_struct_failed;
 748         }
 749
 750         buffer->data = alloc->buffer;
 751         list_add(&buffer->entry, &alloc->buffers);
 752         buffer->free = 1;
 753         binder_insert_free_buffer(alloc, buffer);
 754         alloc->free_async_space = alloc->buffer_size / 2;
 755         binder_alloc_set_vma(alloc, vma);
 756         mmgrab(alloc->vma_vm_mm);
 757
 758         return 0;
 759
 760 err_alloc_buf_struct_failed:
 761         kfree(alloc->pages);
 762         alloc->pages = NULL;
 763 err_alloc_pages_failed:
 764         mutex_lock(&binder_alloc_mmap_lock);
 765         vfree(alloc->buffer);
 766         alloc->buffer = NULL;
 767 err_get_vm_area_failed:
 768 err_already_mapped:
 769         mutex_unlock(&binder_alloc_mmap_lock);
 770         binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 771                            "%s: %d %lx-%lx %s failed %d\n", __func__,
 772                            alloc->pid, vma->vm_start, vma->vm_end,
 773                            failure_string, ret);
 774         return ret;
 775 }
 776
 777
 778 void binder_alloc_deferred_release(struct binder_alloc *alloc)
 779 {
 780         struct rb_node *n;
 781         int buffers, page_count;
 782         struct binder_buffer *buffer;
 783
 784         buffers = 0;
 785         mutex_lock(&alloc->mutex);
 786         BUG_ON(alloc->vma);
 787
 788         while ((n = rb_first(&alloc->allocated_buffers))) {
 789                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 790
 791                 /* Transaction should already have been freed */
 792                 BUG_ON(buffer->transaction);
 793
 794                 binder_free_buf_locked(alloc, buffer);
 795                 buffers++;
 796         }
 797
 798         while (!list_empty(&alloc->buffers)) {
 799                 buffer = list_first_entry(&alloc->buffers,
 800                                           struct binder_buffer, entry);
 801                 WARN_ON(!buffer->free);
 802
 803                 list_del(&buffer->entry);
 804                 WARN_ON_ONCE(!list_empty(&alloc->buffers));
 805                 kfree(buffer);
 806         }
 807
 808         page_count = 0;
 809         if (alloc->pages) {
 810                 int i;
 811
 812                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 813                         void *page_addr;
 814                         bool on_lru;
 815
 816                         if (!alloc->pages[i].page_ptr)
 817                                 continue;
 818
 819                         on_lru = list_lru_del(&binder_alloc_lru,
 820                                               &alloc->pages[i].lru);
 821                         page_addr = alloc->buffer + i * PAGE_SIZE;
 822                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 823                                      "%s: %d: page %d at %pK %s\n",
 824                                      __func__, alloc->pid, i, page_addr,
 825                                      on_lru ? "on lru" : "active");
 826                         unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
 827                         __free_page(alloc->pages[i].page_ptr);
 828                         page_count++;
 829                 }
 830                 kfree(alloc->pages);
 831                 vfree(alloc->buffer);
 832         }
 833         mutex_unlock(&alloc->mutex);
 834         if (alloc->vma_vm_mm)
 835                 mmdrop(alloc->vma_vm_mm);
 836
 837         binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
 838                      "%s: %d buffers %d, pages %d\n",
 839                      __func__, alloc->pid, buffers, page_count);
 840 }
 841
 842 static void print_binder_buffer(struct seq_file *m, const char *prefix,
 843                                 struct binder_buffer *buffer)
 844 {
 845         seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
 846                    prefix, buffer->debug_id, buffer->data,
 847                    buffer->data_size, buffer->offsets_size,
 848                    buffer->extra_buffers_size,
 849                    buffer->transaction ? "active" : "delivered");
 850 }
 851
 852 /**
 853  * binder_alloc_print_allocated() - print buffer info
 854  * @m:     seq_file for output via seq_printf()
 855  * @alloc: binder_alloc for this proc
 856  *
 857  * Prints information about every buffer associated with
 858  * the binder_alloc state to the given seq_file
 859  */
 860 void binder_alloc_print_allocated(struct seq_file *m,
 861                                   struct binder_alloc *alloc)
 862 {
 863         struct rb_node *n;
 864
 865         mutex_lock(&alloc->mutex);
 866         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 867                 print_binder_buffer(m, "  buffer",
 868                                     rb_entry(n, struct binder_buffer, rb_node));
 869         mutex_unlock(&alloc->mutex);
 870 }
 871
 872 /**
 873  * binder_alloc_print_pages() - print page usage
 874  * @m:     seq_file for output via seq_printf()
 875  * @alloc: binder_alloc for this proc
 876  */
 877 void binder_alloc_print_pages(struct seq_file *m,
 878                               struct binder_alloc *alloc)
 879 {
 880         struct binder_lru_page *page;
 881         int i;
 882         int active = 0;
 883         int lru = 0;
 884         int free = 0;
 885
 886         mutex_lock(&alloc->mutex);
 887         for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 888                 page = &alloc->pages[i];
 889                 if (!page->page_ptr)
 890                         free++;
 891                 else if (list_empty(&page->lru))
 892                         active++;
 893                 else
 894                         lru++;
 895         }
 896         mutex_unlock(&alloc->mutex);
 897         seq_printf(m, "  pages: %d:%d:%d\n", active, lru, free);
 898         seq_printf(m, "  pages high watermark: %zu\n", alloc->pages_high);
 899 }
 900
 901 /**
 902  * binder_alloc_get_allocated_count() - return count of buffers
 903  * @alloc: binder_alloc for this proc
 904  *
 905  * Return: count of allocated buffers
 906  */
 907 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
 908 {
 909         struct rb_node *n;
 910         int count = 0;
 911
 912         mutex_lock(&alloc->mutex);
 913         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 914                 count++;
 915         mutex_unlock(&alloc->mutex);
 916         return count;
 917 }
 918
 919
 920 /**
 921  * binder_alloc_vma_close() - invalidate address space
 922  * @alloc: binder_alloc for this proc
 923  *
 924  * Called from binder_vma_close() when releasing address space.
 925  * Clears alloc->vma to prevent new incoming transactions from
 926  * allocating more buffers.
 927  */
 928 void binder_alloc_vma_close(struct binder_alloc *alloc)
 929 {
 930         binder_alloc_set_vma(alloc, NULL);
 931 }
 932
 933 /**
 934  * binder_alloc_free_page() - shrinker callback to free pages
 935  * @item:   item to free
 936  * @lock:   lock protecting the item
 937  * @cb_arg: callback argument
 938  *
 939  * Called from list_lru_walk() in binder_shrink_scan() to free
 940  * up pages when the system is under memory pressure.
 941  */
 942 enum lru_status binder_alloc_free_page(struct list_head *item,
 943                                        struct list_lru_one *lru,
 944                                        spinlock_t *lock,
 945                                        void *cb_arg)
 946 {
 947         struct mm_struct *mm = NULL;
 948         struct binder_lru_page *page = container_of(item,
 949                                                     struct binder_lru_page,
 950                                                     lru);
 951         struct binder_alloc *alloc;
 952         uintptr_t page_addr;
 953         size_t index;
 954         struct vm_area_struct *vma;
 955
 956         alloc = page->alloc;
 957         if (!mutex_trylock(&alloc->mutex))
 958                 goto err_get_alloc_mutex_failed;
 959
 960         if (!page->page_ptr)
 961                 goto err_page_already_freed;
 962
 963         index = page - alloc->pages;
 964         page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
 965         vma = binder_alloc_get_vma(alloc);
 966         if (vma) {
 967                 if (!mmget_not_zero(alloc->vma_vm_mm))
 968                         goto err_mmget;
 969                 mm = alloc->vma_vm_mm;
 970                 if (!down_write_trylock(&mm->mmap_sem))
 971                         goto err_down_write_mmap_sem_failed;
 972         }
 973
 974         list_lru_isolate(lru, item);
 975         spin_unlock(lock);
 976
 977         if (vma) {
 978                 trace_binder_unmap_user_start(alloc, index);
 979
 980                 zap_page_range(vma,
 981                                page_addr + alloc->user_buffer_offset,
 982                                PAGE_SIZE);
 983
 984                 trace_binder_unmap_user_end(alloc, index);
 985
 986                 up_write(&mm->mmap_sem);
 987                 mmput(mm);
 988         }
 989
 990         trace_binder_unmap_kernel_start(alloc, index);
 991
 992         unmap_kernel_range(page_addr, PAGE_SIZE);
 993         __free_page(page->page_ptr);
 994         page->page_ptr = NULL;
 995
 996         trace_binder_unmap_kernel_end(alloc, index);
 997
 998         spin_lock(lock);
 999         mutex_unlock(&alloc->mutex);
1000         return LRU_REMOVED_RETRY;
1001
1002 err_down_write_mmap_sem_failed:
1003         mmput_async(mm);
1004 err_mmget:
1005 err_page_already_freed:
1006         mutex_unlock(&alloc->mutex);
1007 err_get_alloc_mutex_failed:
1008         return LRU_SKIP;
1009 }
1010
1011 static unsigned long
1012 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
1013 {
1014         unsigned long ret = list_lru_count(&binder_alloc_lru);
1015         return ret;
1016 }
1017
1018 static unsigned long
1019 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1020 {
1021         unsigned long ret;
1022
1023         ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
1024                             NULL, sc->nr_to_scan);
1025         return ret;
1026 }
1027
1028 static struct shrinker binder_shrinker = {
1029         .count_objects = binder_shrink_count,
1030         .scan_objects = binder_shrink_scan,
1031         .seeks = DEFAULT_SEEKS,
1032 };
1033
1034 /**
1035  * binder_alloc_init() - called by binder_open() for per-proc initialization
1036  * @alloc: binder_alloc for this proc
1037  *
1038  * Called from binder_open() to initialize binder_alloc fields for
1039  * new binder proc
1040  */
1041 void binder_alloc_init(struct binder_alloc *alloc)
1042 {
1043         alloc->pid = current->group_leader->pid;
1044         mutex_init(&alloc->mutex);
1045         INIT_LIST_HEAD(&alloc->buffers);
1046 }
1047
1048 int binder_alloc_shrinker_init(void)
1049 {
1050         int ret = list_lru_init(&binder_alloc_lru);
1051
1052         if (ret == 0) {
1053                 ret = register_shrinker(&binder_shrinker);
1054                 if (ret)
1055                         list_lru_destroy(&binder_alloc_lru);
1056         }
1057         return ret;
1058 }