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 when in use by kernel or
 153                          * after it's already been freed.
 154                          */
 155                         if (!buffer->allow_user_free)
 156                                 return ERR_PTR(-EPERM);
 157                         buffer->allow_user_free = 0;
 158                         return buffer;
 159                 }
 160         }
 161         return NULL;
 162 }
 163
 164 /**
 165  * binder_alloc_buffer_lookup() - get buffer given user ptr
 166  * @alloc:      binder_alloc for this proc
 167  * @user_ptr:   User pointer to buffer data
 168  *
 169  * Validate userspace pointer to buffer data and return buffer corresponding to
 170  * that user pointer. Search the rb tree for buffer that matches user data
 171  * pointer.
 172  *
 173  * Return:      Pointer to buffer or NULL
 174  */
 175 struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
 176                                                    uintptr_t user_ptr)
 177 {
 178         struct binder_buffer *buffer;
 179
 180         mutex_lock(&alloc->mutex);
 181         buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
 182         mutex_unlock(&alloc->mutex);
 183         return buffer;
 184 }
 185
 186 static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
 187                                     void *start, void *end,
 188                                     struct vm_area_struct *vma)
 189 {
 190         void *page_addr;
 191         unsigned long user_page_addr;
 192         struct binder_lru_page *page;
 193         struct mm_struct *mm = NULL;
 194         bool need_mm = false;
 195
 196         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 197                      "%d: %s pages %pK-%pK\n", alloc->pid,
 198                      allocate ? "allocate" : "free", start, end);
 199
 200         if (end <= start)
 201                 return 0;
 202
 203         trace_binder_update_page_range(alloc, allocate, start, end);
 204
 205         if (allocate == 0)
 206                 goto free_range;
 207
 208         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 209                 page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
 210                 if (!page->page_ptr) {
 211                         need_mm = true;
 212                         break;
 213                 }
 214         }
 215
 216         if (!vma && need_mm && mmget_not_zero(alloc->vma_vm_mm))
 217                 mm = alloc->vma_vm_mm;
 218
 219         if (mm) {
 220                 down_write(&mm->mmap_sem);
 221                 vma = alloc->vma;
 222         }
 223
 224         if (!vma && need_mm) {
 225                 pr_err("%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
 226                         alloc->pid);
 227                 goto err_no_vma;
 228         }
 229
 230         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 231                 int ret;
 232                 bool on_lru;
 233                 size_t index;
 234
 235                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 236                 page = &alloc->pages[index];
 237
 238                 if (page->page_ptr) {
 239                         trace_binder_alloc_lru_start(alloc, index);
 240
 241                         on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
 242                         WARN_ON(!on_lru);
 243
 244                         trace_binder_alloc_lru_end(alloc, index);
 245                         continue;
 246                 }
 247
 248                 if (WARN_ON(!vma))
 249                         goto err_page_ptr_cleared;
 250
 251                 trace_binder_alloc_page_start(alloc, index);
 252                 page->page_ptr = alloc_page(GFP_KERNEL |
 253                                             __GFP_HIGHMEM |
 254                                             __GFP_ZERO);
 255                 if (!page->page_ptr) {
 256                         pr_err("%d: binder_alloc_buf failed for page at %pK\n",
 257                                 alloc->pid, page_addr);
 258                         goto err_alloc_page_failed;
 259                 }
 260                 page->alloc = alloc;
 261                 INIT_LIST_HEAD(&page->lru);
 262
 263                 ret = map_kernel_range_noflush((unsigned long)page_addr,
 264                                                PAGE_SIZE, PAGE_KERNEL,
 265                                                &page->page_ptr);
 266                 flush_cache_vmap((unsigned long)page_addr,
 267                                 (unsigned long)page_addr + PAGE_SIZE);
 268                 if (ret != 1) {
 269                         pr_err("%d: binder_alloc_buf failed to map page at %pK in kernel\n",
 270                                alloc->pid, page_addr);
 271                         goto err_map_kernel_failed;
 272                 }
 273                 user_page_addr =
 274                         (uintptr_t)page_addr + alloc->user_buffer_offset;
 275                 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
 276                 if (ret) {
 277                         pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
 278                                alloc->pid, user_page_addr);
 279                         goto err_vm_insert_page_failed;
 280                 }
 281
 282                 trace_binder_alloc_page_end(alloc, index);
 283                 /* vm_insert_page does not seem to increment the refcount */
 284         }
 285         if (mm) {
 286                 up_write(&mm->mmap_sem);
 287                 mmput(mm);
 288         }
 289         return 0;
 290
 291 free_range:
 292         for (page_addr = end - PAGE_SIZE; page_addr >= start;
 293              page_addr -= PAGE_SIZE) {
 294                 bool ret;
 295                 size_t index;
 296
 297                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 298                 page = &alloc->pages[index];
 299
 300                 trace_binder_free_lru_start(alloc, index);
 301
 302                 ret = list_lru_add(&binder_alloc_lru, &page->lru);
 303                 WARN_ON(!ret);
 304
 305                 trace_binder_free_lru_end(alloc, index);
 306                 continue;
 307
 308 err_vm_insert_page_failed:
 309                 unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
 310 err_map_kernel_failed:
 311                 __free_page(page->page_ptr);
 312                 page->page_ptr = NULL;
 313 err_alloc_page_failed:
 314 err_page_ptr_cleared:
 315                 ;
 316         }
 317 err_no_vma:
 318         if (mm) {
 319                 up_write(&mm->mmap_sem);
 320                 mmput(mm);
 321         }
 322         return vma ? -ENOMEM : -ESRCH;
 323 }
 324
 325 static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
 326                 struct vm_area_struct *vma)
 327 {
 328         if (vma)
 329                 alloc->vma_vm_mm = vma->vm_mm;
 330         /*
 331          * If we see alloc->vma is not NULL, buffer data structures set up
 332          * completely. Look at smp_rmb side binder_alloc_get_vma.
 333          * We also want to guarantee new alloc->vma_vm_mm is always visible
 334          * if alloc->vma is set.
 335          */
 336         smp_wmb();
 337         alloc->vma = vma;
 338 }
 339
 340 static inline struct vm_area_struct *binder_alloc_get_vma(
 341                 struct binder_alloc *alloc)
 342 {
 343         struct vm_area_struct *vma = NULL;
 344
 345         if (alloc->vma) {
 346                 /* Look at description in binder_alloc_set_vma */
 347                 smp_rmb();
 348                 vma = alloc->vma;
 349         }
 350         return vma;
 351 }
 352
 353 struct binder_buffer *binder_alloc_new_buf_locked(struct binder_alloc *alloc,
 354                                                   size_t data_size,
 355                                                   size_t offsets_size,
 356                                                   size_t extra_buffers_size,
 357                                                   int is_async)
 358 {
 359         struct rb_node *n = alloc->free_buffers.rb_node;
 360         struct binder_buffer *buffer;
 361         size_t buffer_size;
 362         struct rb_node *best_fit = NULL;
 363         void *has_page_addr;
 364         void *end_page_addr;
 365         size_t size, data_offsets_size;
 366         int ret;
 367
 368         if (!binder_alloc_get_vma(alloc)) {
 369                 pr_err("%d: binder_alloc_buf, no vma\n",
 370                        alloc->pid);
 371                 return ERR_PTR(-ESRCH);
 372         }
 373
 374         data_offsets_size = ALIGN(data_size, sizeof(void *)) +
 375                 ALIGN(offsets_size, sizeof(void *));
 376
 377         if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
 378                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 379                                 "%d: got transaction with invalid size %zd-%zd\n",
 380                                 alloc->pid, data_size, offsets_size);
 381                 return ERR_PTR(-EINVAL);
 382         }
 383         size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
 384         if (size < data_offsets_size || size < extra_buffers_size) {
 385                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 386                                 "%d: got transaction with invalid extra_buffers_size %zd\n",
 387                                 alloc->pid, extra_buffers_size);
 388                 return ERR_PTR(-EINVAL);
 389         }
 390         if (is_async &&
 391             alloc->free_async_space < size + sizeof(struct binder_buffer)) {
 392                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 393                              "%d: binder_alloc_buf size %zd failed, no async space left\n",
 394                               alloc->pid, size);
 395                 return ERR_PTR(-ENOSPC);
 396         }
 397
 398         /* Pad 0-size buffers so they get assigned unique addresses */
 399         size = max(size, sizeof(void *));
 400
 401         while (n) {
 402                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 403                 BUG_ON(!buffer->free);
 404                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 405
 406                 if (size < buffer_size) {
 407                         best_fit = n;
 408                         n = n->rb_left;
 409                 } else if (size > buffer_size)
 410                         n = n->rb_right;
 411                 else {
 412                         best_fit = n;
 413                         break;
 414                 }
 415         }
 416         if (best_fit == NULL) {
 417                 size_t allocated_buffers = 0;
 418                 size_t largest_alloc_size = 0;
 419                 size_t total_alloc_size = 0;
 420                 size_t free_buffers = 0;
 421                 size_t largest_free_size = 0;
 422                 size_t total_free_size = 0;
 423
 424                 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 425                      n = rb_next(n)) {
 426                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 427                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 428                         allocated_buffers++;
 429                         total_alloc_size += buffer_size;
 430                         if (buffer_size > largest_alloc_size)
 431                                 largest_alloc_size = buffer_size;
 432                 }
 433                 for (n = rb_first(&alloc->free_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                         free_buffers++;
 438                         total_free_size += buffer_size;
 439                         if (buffer_size > largest_free_size)
 440                                 largest_free_size = buffer_size;
 441                 }
 442                 pr_err("%d: binder_alloc_buf size %zd failed, no address space\n",
 443                         alloc->pid, size);
 444                 pr_err("allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
 445                        total_alloc_size, allocated_buffers, largest_alloc_size,
 446                        total_free_size, free_buffers, largest_free_size);
 447                 return ERR_PTR(-ENOSPC);
 448         }
 449         if (n == NULL) {
 450                 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
 451                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 452         }
 453
 454         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 455                      "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
 456                       alloc->pid, size, buffer, buffer_size);
 457
 458         has_page_addr =
 459                 (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK);
 460         WARN_ON(n && buffer_size != size);
 461         end_page_addr =
 462                 (void *)PAGE_ALIGN((uintptr_t)buffer->data + size);
 463         if (end_page_addr > has_page_addr)
 464                 end_page_addr = has_page_addr;
 465         ret = binder_update_page_range(alloc, 1,
 466             (void *)PAGE_ALIGN((uintptr_t)buffer->data), end_page_addr, NULL);
 467         if (ret)
 468                 return ERR_PTR(ret);
 469
 470         if (buffer_size != size) {
 471                 struct binder_buffer *new_buffer;
 472
 473                 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 474                 if (!new_buffer) {
 475                         pr_err("%s: %d failed to alloc new buffer struct\n",
 476                                __func__, alloc->pid);
 477                         goto err_alloc_buf_struct_failed;
 478                 }
 479                 new_buffer->data = (u8 *)buffer->data + size;
 480                 list_add(&new_buffer->entry, &buffer->entry);
 481                 new_buffer->free = 1;
 482                 binder_insert_free_buffer(alloc, new_buffer);
 483         }
 484
 485         rb_erase(best_fit, &alloc->free_buffers);
 486         buffer->free = 0;
 487         buffer->allow_user_free = 0;
 488         binder_insert_allocated_buffer_locked(alloc, buffer);
 489         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 490                      "%d: binder_alloc_buf size %zd got %pK\n",
 491                       alloc->pid, size, buffer);
 492         buffer->data_size = data_size;
 493         buffer->offsets_size = offsets_size;
 494         buffer->async_transaction = is_async;
 495         buffer->extra_buffers_size = extra_buffers_size;
 496         if (is_async) {
 497                 alloc->free_async_space -= size + sizeof(struct binder_buffer);
 498                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 499                              "%d: binder_alloc_buf size %zd async free %zd\n",
 500                               alloc->pid, size, alloc->free_async_space);
 501         }
 502         return buffer;
 503
 504 err_alloc_buf_struct_failed:
 505         binder_update_page_range(alloc, 0,
 506                                  (void *)PAGE_ALIGN((uintptr_t)buffer->data),
 507                                  end_page_addr, NULL);
 508         return ERR_PTR(-ENOMEM);
 509 }
 510
 511 /**
 512  * binder_alloc_new_buf() - Allocate a new binder buffer
 513  * @alloc:              binder_alloc for this proc
 514  * @data_size:          size of user data buffer
 515  * @offsets_size:       user specified buffer offset
 516  * @extra_buffers_size: size of extra space for meta-data (eg, security context)
 517  * @is_async:           buffer for async transaction
 518  *
 519  * Allocate a new buffer given the requested sizes. Returns
 520  * the kernel version of the buffer pointer. The size allocated
 521  * is the sum of the three given sizes (each rounded up to
 522  * pointer-sized boundary)
 523  *
 524  * Return:      The allocated buffer or %NULL if error
 525  */
 526 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 527                                            size_t data_size,
 528                                            size_t offsets_size,
 529                                            size_t extra_buffers_size,
 530                                            int is_async)
 531 {
 532         struct binder_buffer *buffer;
 533
 534         mutex_lock(&alloc->mutex);
 535         buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
 536                                              extra_buffers_size, is_async);
 537         mutex_unlock(&alloc->mutex);
 538         return buffer;
 539 }
 540
 541 static void *buffer_start_page(struct binder_buffer *buffer)
 542 {
 543         return (void *)((uintptr_t)buffer->data & PAGE_MASK);
 544 }
 545
 546 static void *prev_buffer_end_page(struct binder_buffer *buffer)
 547 {
 548         return (void *)(((uintptr_t)(buffer->data) - 1) & PAGE_MASK);
 549 }
 550
 551 static void binder_delete_free_buffer(struct binder_alloc *alloc,
 552                                       struct binder_buffer *buffer)
 553 {
 554         struct binder_buffer *prev, *next = NULL;
 555         bool to_free = true;
 556         BUG_ON(alloc->buffers.next == &buffer->entry);
 557         prev = binder_buffer_prev(buffer);
 558         BUG_ON(!prev->free);
 559         if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
 560                 to_free = false;
 561                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 562                                    "%d: merge free, buffer %pK share page with %pK\n",
 563                                    alloc->pid, buffer->data, prev->data);
 564         }
 565
 566         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 567                 next = binder_buffer_next(buffer);
 568                 if (buffer_start_page(next) == buffer_start_page(buffer)) {
 569                         to_free = false;
 570                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 571                                            "%d: merge free, buffer %pK share page with %pK\n",
 572                                            alloc->pid,
 573                                            buffer->data,
 574                                            next->data);
 575                 }
 576         }
 577
 578         if (PAGE_ALIGNED(buffer->data)) {
 579                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 580                                    "%d: merge free, buffer start %pK is page aligned\n",
 581                                    alloc->pid, buffer->data);
 582                 to_free = false;
 583         }
 584
 585         if (to_free) {
 586                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 587                                    "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
 588                                    alloc->pid, buffer->data,
 589                                    prev->data, next ? next->data : NULL);
 590                 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
 591                                          buffer_start_page(buffer) + PAGE_SIZE,
 592                                          NULL);
 593         }
 594         list_del(&buffer->entry);
 595         kfree(buffer);
 596 }
 597
 598 static void binder_free_buf_locked(struct binder_alloc *alloc,
 599                                    struct binder_buffer *buffer)
 600 {
 601         size_t size, buffer_size;
 602
 603         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 604
 605         size = ALIGN(buffer->data_size, sizeof(void *)) +
 606                 ALIGN(buffer->offsets_size, sizeof(void *)) +
 607                 ALIGN(buffer->extra_buffers_size, sizeof(void *));
 608
 609         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 610                      "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
 611                       alloc->pid, buffer, size, buffer_size);
 612
 613         BUG_ON(buffer->free);
 614         BUG_ON(size > buffer_size);
 615         BUG_ON(buffer->transaction != NULL);
 616         BUG_ON(buffer->data < alloc->buffer);
 617         BUG_ON(buffer->data > alloc->buffer + alloc->buffer_size);
 618
 619         if (buffer->async_transaction) {
 620                 alloc->free_async_space += size + sizeof(struct binder_buffer);
 621
 622                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 623                              "%d: binder_free_buf size %zd async free %zd\n",
 624                               alloc->pid, size, alloc->free_async_space);
 625         }
 626
 627         binder_update_page_range(alloc, 0,
 628                 (void *)PAGE_ALIGN((uintptr_t)buffer->data),
 629                 (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK),
 630                 NULL);
 631
 632         rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
 633         buffer->free = 1;
 634         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 635                 struct binder_buffer *next = binder_buffer_next(buffer);
 636
 637                 if (next->free) {
 638                         rb_erase(&next->rb_node, &alloc->free_buffers);
 639                         binder_delete_free_buffer(alloc, next);
 640                 }
 641         }
 642         if (alloc->buffers.next != &buffer->entry) {
 643                 struct binder_buffer *prev = binder_buffer_prev(buffer);
 644
 645                 if (prev->free) {
 646                         binder_delete_free_buffer(alloc, buffer);
 647                         rb_erase(&prev->rb_node, &alloc->free_buffers);
 648                         buffer = prev;
 649                 }
 650         }
 651         binder_insert_free_buffer(alloc, buffer);
 652 }
 653
 654 /**
 655  * binder_alloc_free_buf() - free a binder buffer
 656  * @alloc:      binder_alloc for this proc
 657  * @buffer:     kernel pointer to buffer
 658  *
 659  * Free the buffer allocated via binder_alloc_new_buffer()
 660  */
 661 void binder_alloc_free_buf(struct binder_alloc *alloc,
 662                             struct binder_buffer *buffer)
 663 {
 664         mutex_lock(&alloc->mutex);
 665         binder_free_buf_locked(alloc, buffer);
 666         mutex_unlock(&alloc->mutex);
 667 }
 668
 669 /**
 670  * binder_alloc_mmap_handler() - map virtual address space for proc
 671  * @alloc:      alloc structure for this proc
 672  * @vma:        vma passed to mmap()
 673  *
 674  * Called by binder_mmap() to initialize the space specified in
 675  * vma for allocating binder buffers
 676  *
 677  * Return:
 678  *      0 = success
 679  *      -EBUSY = address space already mapped
 680  *      -ENOMEM = failed to map memory to given address space
 681  */
 682 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 683                               struct vm_area_struct *vma)
 684 {
 685         int ret;
 686         struct vm_struct *area;
 687         const char *failure_string;
 688         struct binder_buffer *buffer;
 689
 690         mutex_lock(&binder_alloc_mmap_lock);
 691         if (alloc->buffer) {
 692                 ret = -EBUSY;
 693                 failure_string = "already mapped";
 694                 goto err_already_mapped;
 695         }
 696
 697         area = get_vm_area(vma->vm_end - vma->vm_start, VM_ALLOC);
 698         if (area == NULL) {
 699                 ret = -ENOMEM;
 700                 failure_string = "get_vm_area";
 701                 goto err_get_vm_area_failed;
 702         }
 703         alloc->buffer = area->addr;
 704         alloc->user_buffer_offset =
 705                 vma->vm_start - (uintptr_t)alloc->buffer;
 706         mutex_unlock(&binder_alloc_mmap_lock);
 707
 708 #ifdef CONFIG_CPU_CACHE_VIPT
 709         if (cache_is_vipt_aliasing()) {
 710                 while (CACHE_COLOUR(
 711                                 (vma->vm_start ^ (uint32_t)alloc->buffer))) {
 712                         pr_info("%s: %d %lx-%lx maps %pK bad alignment\n",
 713                                 __func__, alloc->pid, vma->vm_start,
 714                                 vma->vm_end, alloc->buffer);
 715                         vma->vm_start += PAGE_SIZE;
 716                 }
 717         }
 718 #endif
 719         alloc->pages = kzalloc(sizeof(alloc->pages[0]) *
 720                                    ((vma->vm_end - vma->vm_start) / PAGE_SIZE),
 721                                GFP_KERNEL);
 722         if (alloc->pages == NULL) {
 723                 ret = -ENOMEM;
 724                 failure_string = "alloc page array";
 725                 goto err_alloc_pages_failed;
 726         }
 727         alloc->buffer_size = vma->vm_end - vma->vm_start;
 728
 729         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 730         if (!buffer) {
 731                 ret = -ENOMEM;
 732                 failure_string = "alloc buffer struct";
 733                 goto err_alloc_buf_struct_failed;
 734         }
 735
 736         buffer->data = alloc->buffer;
 737         list_add(&buffer->entry, &alloc->buffers);
 738         buffer->free = 1;
 739         binder_insert_free_buffer(alloc, buffer);
 740         alloc->free_async_space = alloc->buffer_size / 2;
 741         binder_alloc_set_vma(alloc, vma);
 742         mmgrab(alloc->vma_vm_mm);
 743
 744         return 0;
 745
 746 err_alloc_buf_struct_failed:
 747         kfree(alloc->pages);
 748         alloc->pages = NULL;
 749 err_alloc_pages_failed:
 750         mutex_lock(&binder_alloc_mmap_lock);
 751         vfree(alloc->buffer);
 752         alloc->buffer = NULL;
 753 err_get_vm_area_failed:
 754 err_already_mapped:
 755         mutex_unlock(&binder_alloc_mmap_lock);
 756         pr_err("%s: %d %lx-%lx %s failed %d\n", __func__,
 757                alloc->pid, vma->vm_start, vma->vm_end, failure_string, ret);
 758         return ret;
 759 }
 760
 761
 762 void binder_alloc_deferred_release(struct binder_alloc *alloc)
 763 {
 764         struct rb_node *n;
 765         int buffers, page_count;
 766         struct binder_buffer *buffer;
 767
 768         buffers = 0;
 769         mutex_lock(&alloc->mutex);
 770         BUG_ON(alloc->vma);
 771
 772         while ((n = rb_first(&alloc->allocated_buffers))) {
 773                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 774
 775                 /* Transaction should already have been freed */
 776                 BUG_ON(buffer->transaction);
 777
 778                 binder_free_buf_locked(alloc, buffer);
 779                 buffers++;
 780         }
 781
 782         while (!list_empty(&alloc->buffers)) {
 783                 buffer = list_first_entry(&alloc->buffers,
 784                                           struct binder_buffer, entry);
 785                 WARN_ON(!buffer->free);
 786
 787                 list_del(&buffer->entry);
 788                 WARN_ON_ONCE(!list_empty(&alloc->buffers));
 789                 kfree(buffer);
 790         }
 791
 792         page_count = 0;
 793         if (alloc->pages) {
 794                 int i;
 795
 796                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 797                         void *page_addr;
 798                         bool on_lru;
 799
 800                         if (!alloc->pages[i].page_ptr)
 801                                 continue;
 802
 803                         on_lru = list_lru_del(&binder_alloc_lru,
 804                                               &alloc->pages[i].lru);
 805                         page_addr = alloc->buffer + i * PAGE_SIZE;
 806                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 807                                      "%s: %d: page %d at %pK %s\n",
 808                                      __func__, alloc->pid, i, page_addr,
 809                                      on_lru ? "on lru" : "active");
 810                         unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
 811                         __free_page(alloc->pages[i].page_ptr);
 812                         page_count++;
 813                 }
 814                 kfree(alloc->pages);
 815                 vfree(alloc->buffer);
 816         }
 817         mutex_unlock(&alloc->mutex);
 818         if (alloc->vma_vm_mm)
 819                 mmdrop(alloc->vma_vm_mm);
 820
 821         binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
 822                      "%s: %d buffers %d, pages %d\n",
 823                      __func__, alloc->pid, buffers, page_count);
 824 }
 825
 826 static void print_binder_buffer(struct seq_file *m, const char *prefix,
 827                                 struct binder_buffer *buffer)
 828 {
 829         seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
 830                    prefix, buffer->debug_id, buffer->data,
 831                    buffer->data_size, buffer->offsets_size,
 832                    buffer->extra_buffers_size,
 833                    buffer->transaction ? "active" : "delivered");
 834 }
 835
 836 /**
 837  * binder_alloc_print_allocated() - print buffer info
 838  * @m:     seq_file for output via seq_printf()
 839  * @alloc: binder_alloc for this proc
 840  *
 841  * Prints information about every buffer associated with
 842  * the binder_alloc state to the given seq_file
 843  */
 844 void binder_alloc_print_allocated(struct seq_file *m,
 845                                   struct binder_alloc *alloc)
 846 {
 847         struct rb_node *n;
 848
 849         mutex_lock(&alloc->mutex);
 850         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 851                 print_binder_buffer(m, "  buffer",
 852                                     rb_entry(n, struct binder_buffer, rb_node));
 853         mutex_unlock(&alloc->mutex);
 854 }
 855
 856 /**
 857  * binder_alloc_print_pages() - print page usage
 858  * @m:     seq_file for output via seq_printf()
 859  * @alloc: binder_alloc for this proc
 860  */
 861 void binder_alloc_print_pages(struct seq_file *m,
 862                               struct binder_alloc *alloc)
 863 {
 864         struct binder_lru_page *page;
 865         int i;
 866         int active = 0;
 867         int lru = 0;
 868         int free = 0;
 869
 870         mutex_lock(&alloc->mutex);
 871         for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 872                 page = &alloc->pages[i];
 873                 if (!page->page_ptr)
 874                         free++;
 875                 else if (list_empty(&page->lru))
 876                         active++;
 877                 else
 878                         lru++;
 879         }
 880         mutex_unlock(&alloc->mutex);
 881         seq_printf(m, "  pages: %d:%d:%d\n", active, lru, free);
 882 }
 883
 884 /**
 885  * binder_alloc_get_allocated_count() - return count of buffers
 886  * @alloc: binder_alloc for this proc
 887  *
 888  * Return: count of allocated buffers
 889  */
 890 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
 891 {
 892         struct rb_node *n;
 893         int count = 0;
 894
 895         mutex_lock(&alloc->mutex);
 896         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 897                 count++;
 898         mutex_unlock(&alloc->mutex);
 899         return count;
 900 }
 901
 902
 903 /**
 904  * binder_alloc_vma_close() - invalidate address space
 905  * @alloc: binder_alloc for this proc
 906  *
 907  * Called from binder_vma_close() when releasing address space.
 908  * Clears alloc->vma to prevent new incoming transactions from
 909  * allocating more buffers.
 910  */
 911 void binder_alloc_vma_close(struct binder_alloc *alloc)
 912 {
 913         binder_alloc_set_vma(alloc, NULL);
 914 }
 915
 916 /**
 917  * binder_alloc_free_page() - shrinker callback to free pages
 918  * @item:   item to free
 919  * @lock:   lock protecting the item
 920  * @cb_arg: callback argument
 921  *
 922  * Called from list_lru_walk() in binder_shrink_scan() to free
 923  * up pages when the system is under memory pressure.
 924  */
 925 enum lru_status binder_alloc_free_page(struct list_head *item,
 926                                        struct list_lru_one *lru,
 927                                        spinlock_t *lock,
 928                                        void *cb_arg)
 929 {
 930         struct mm_struct *mm = NULL;
 931         struct binder_lru_page *page = container_of(item,
 932                                                     struct binder_lru_page,
 933                                                     lru);
 934         struct binder_alloc *alloc;
 935         uintptr_t page_addr;
 936         size_t index;
 937         struct vm_area_struct *vma;
 938
 939         alloc = page->alloc;
 940         if (!mutex_trylock(&alloc->mutex))
 941                 goto err_get_alloc_mutex_failed;
 942
 943         if (!page->page_ptr)
 944                 goto err_page_already_freed;
 945
 946         index = page - alloc->pages;
 947         page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
 948         vma = binder_alloc_get_vma(alloc);
 949         if (vma) {
 950                 if (!mmget_not_zero(alloc->vma_vm_mm))
 951                         goto err_mmget;
 952                 mm = alloc->vma_vm_mm;
 953                 if (!down_write_trylock(&mm->mmap_sem))
 954                         goto err_down_write_mmap_sem_failed;
 955         }
 956
 957         list_lru_isolate(lru, item);
 958         spin_unlock(lock);
 959
 960         if (vma) {
 961                 trace_binder_unmap_user_start(alloc, index);
 962
 963                 zap_page_range(vma,
 964                                page_addr + alloc->user_buffer_offset,
 965                                PAGE_SIZE);
 966
 967                 trace_binder_unmap_user_end(alloc, index);
 968
 969                 up_write(&mm->mmap_sem);
 970                 mmput(mm);
 971         }
 972
 973         trace_binder_unmap_kernel_start(alloc, index);
 974
 975         unmap_kernel_range(page_addr, PAGE_SIZE);
 976         __free_page(page->page_ptr);
 977         page->page_ptr = NULL;
 978
 979         trace_binder_unmap_kernel_end(alloc, index);
 980
 981         spin_lock(lock);
 982         mutex_unlock(&alloc->mutex);
 983         return LRU_REMOVED_RETRY;
 984
 985 err_down_write_mmap_sem_failed:
 986         mmput_async(mm);
 987 err_mmget:
 988 err_page_already_freed:
 989         mutex_unlock(&alloc->mutex);
 990 err_get_alloc_mutex_failed:
 991         return LRU_SKIP;
 992 }
 993
 994 static unsigned long
 995 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 996 {
 997         unsigned long ret = list_lru_count(&binder_alloc_lru);
 998         return ret;
 999 }
1000
1001 static unsigned long
1002 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1003 {
1004         unsigned long ret;
1005
1006         ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
1007                             NULL, sc->nr_to_scan);
1008         return ret;
1009 }
1010
1011 struct shrinker binder_shrinker = {
1012         .count_objects = binder_shrink_count,
1013         .scan_objects = binder_shrink_scan,
1014         .seeks = DEFAULT_SEEKS,
1015 };
1016
1017 /**
1018  * binder_alloc_init() - called by binder_open() for per-proc initialization
1019  * @alloc: binder_alloc for this proc
1020  *
1021  * Called from binder_open() to initialize binder_alloc fields for
1022  * new binder proc
1023  */
1024 void binder_alloc_init(struct binder_alloc *alloc)
1025 {
1026         alloc->pid = current->group_leader->pid;
1027         mutex_init(&alloc->mutex);
1028         INIT_LIST_HEAD(&alloc->buffers);
1029 }
1030
1031 void binder_alloc_shrinker_init(void)
1032 {
1033         list_lru_init(&binder_alloc_lru);
1034         register_shrinker(&binder_shrinker);
1035 }