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