drivers/android/binder_alloc.c

   1 /* binder_alloc.c
   2  *
   3  * Android IPC Subsystem
   4  *
   5  * Copyright (C) 2007-2017 Google, Inc.
   6  *
   7  * This software is licensed under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation, and
   9  * may be copied, distributed, and modified under those terms.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  */
  17
  18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  19
  20 #include <asm/cacheflush.h>
  21 #include <linux/list.h>
  22 #include <linux/sched/mm.h>
  23 #include <linux/module.h>
  24 #include <linux/rtmutex.h>
  25 #include <linux/rbtree.h>
  26 #include <linux/seq_file.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/slab.h>
  29 #include <linux/sched.h>
  30 #include <linux/list_lru.h>
  31 #include "binder_alloc.h"
  32 #include "binder_trace.h"
  33
  34 struct list_lru binder_alloc_lru;
  35
  36 static DEFINE_MUTEX(binder_alloc_mmap_lock);
  37
  38 enum {
  39         BINDER_DEBUG_OPEN_CLOSE             = 1U << 1,
  40         BINDER_DEBUG_BUFFER_ALLOC           = 1U << 2,
  41         BINDER_DEBUG_BUFFER_ALLOC_ASYNC     = 1U << 3,
  42 };
  43 static uint32_t binder_alloc_debug_mask;
  44
  45 module_param_named(debug_mask, binder_alloc_debug_mask,
  46                    uint, 0644);
  47
  48 #define binder_alloc_debug(mask, x...) \
  49         do { \
  50                 if (binder_alloc_debug_mask & mask) \
  51                         pr_info(x); \
  52         } while (0)
  53
  54 static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
  55 {
  56         return list_entry(buffer->entry.next, struct binder_buffer, entry);
  57 }
  58
  59 static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
  60 {
  61         return list_entry(buffer->entry.prev, struct binder_buffer, entry);
  62 }
  63
  64 static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
  65                                        struct binder_buffer *buffer)
  66 {
  67         if (list_is_last(&buffer->entry, &alloc->buffers))
  68                 return (u8 *)alloc->buffer +
  69                         alloc->buffer_size - (u8 *)buffer->data;
  70         return (u8 *)binder_buffer_next(buffer)->data - (u8 *)buffer->data;
  71 }
  72
  73 static void binder_insert_free_buffer(struct binder_alloc *alloc,
  74                                       struct binder_buffer *new_buffer)
  75 {
  76         struct rb_node **p = &alloc->free_buffers.rb_node;
  77         struct rb_node *parent = NULL;
  78         struct binder_buffer *buffer;
  79         size_t buffer_size;
  80         size_t new_buffer_size;
  81
  82         BUG_ON(!new_buffer->free);
  83
  84         new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
  85
  86         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
  87                      "%d: add free buffer, size %zd, at %pK\n",
  88                       alloc->pid, new_buffer_size, new_buffer);
  89
  90         while (*p) {
  91                 parent = *p;
  92                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
  93                 BUG_ON(!buffer->free);
  94
  95                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
  96
  97                 if (new_buffer_size < buffer_size)
  98                         p = &parent->rb_left;
  99                 else
 100                         p = &parent->rb_right;
 101         }
 102         rb_link_node(&new_buffer->rb_node, parent, p);
 103         rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
 104 }
 105
 106 static void binder_insert_allocated_buffer_locked(
 107                 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
 108 {
 109         struct rb_node **p = &alloc->allocated_buffers.rb_node;
 110         struct rb_node *parent = NULL;
 111         struct binder_buffer *buffer;
 112
 113         BUG_ON(new_buffer->free);
 114
 115         while (*p) {
 116                 parent = *p;
 117                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
 118                 BUG_ON(buffer->free);
 119
 120                 if (new_buffer->data < buffer->data)
 121                         p = &parent->rb_left;
 122                 else if (new_buffer->data > buffer->data)
 123                         p = &parent->rb_right;
 124                 else
 125                         BUG();
 126         }
 127         rb_link_node(&new_buffer->rb_node, parent, p);
 128         rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
 129 }
 130
 131 static struct binder_buffer *binder_alloc_prepare_to_free_locked(
 132                 struct binder_alloc *alloc,
 133                 uintptr_t user_ptr)
 134 {
 135         struct rb_node *n = alloc->allocated_buffers.rb_node;
 136         struct binder_buffer *buffer;
 137         void *kern_ptr;
 138
 139         kern_ptr = (void *)(user_ptr - alloc->user_buffer_offset);
 140
 141         while (n) {
 142                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 143                 BUG_ON(buffer->free);
 144
 145                 if (kern_ptr < buffer->data)
 146                         n = n->rb_left;
 147                 else if (kern_ptr > buffer->data)
 148                         n = n->rb_right;
 149                 else {
 150                         /*
 151                          * Guard against user threads attempting to
 152                          * free the buffer twice
 153                          */
 154                         if (buffer->free_in_progress) {
 155                                 pr_err("%d:%d FREE_BUFFER u%016llx user freed buffer twice\n",
 156                                        alloc->pid, current->pid, (u64)user_ptr);
 157                                 return NULL;
 158                         }
 159                         buffer->free_in_progress = 1;
 160                         return buffer;
 161                 }
 162         }
 163         return NULL;
 164 }
 165
 166 /**
 167  * binder_alloc_buffer_lookup() - get buffer given user ptr
 168  * @alloc:      binder_alloc for this proc
 169  * @user_ptr:   User pointer to buffer data
 170  *
 171  * Validate userspace pointer to buffer data and return buffer corresponding to
 172  * that user pointer. Search the rb tree for buffer that matches user data
 173  * pointer.
 174  *
 175  * Return:      Pointer to buffer or NULL
 176  */
 177 struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
 178                                                    uintptr_t user_ptr)
 179 {
 180         struct binder_buffer *buffer;
 181
 182         mutex_lock(&alloc->mutex);
 183         buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
 184         mutex_unlock(&alloc->mutex);
 185         return buffer;
 186 }
 187
 188 static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
 189                                     void *start, void *end,
 190                                     struct vm_area_struct *vma)
 191 {
 192         void *page_addr;
 193         unsigned long user_page_addr;
 194         struct binder_lru_page *page;
 195         struct mm_struct *mm = NULL;
 196         bool need_mm = false;
 197
 198         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 199                      "%d: %s pages %pK-%pK\n", alloc->pid,
 200                      allocate ? "allocate" : "free", start, end);
 201
 202         if (end <= start)
 203                 return 0;
 204
 205         trace_binder_update_page_range(alloc, allocate, start, end);
 206
 207         if (allocate == 0)
 208                 goto free_range;
 209
 210         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 211                 page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
 212                 if (!page->page_ptr) {
 213                         need_mm = true;
 214                         break;
 215                 }
 216         }
 217
 218         if (!vma && need_mm)
 219                 mm = get_task_mm(alloc->tsk);
 220
 221         if (mm) {
 222                 down_write(&mm->mmap_sem);
 223                 vma = alloc->vma;
 224                 if (vma && mm != alloc->vma_vm_mm) {
 225                         pr_err("%d: vma mm and task mm mismatch\n",
 226                                 alloc->pid);
 227                         vma = NULL;
 228                 }
 229         }
 230
 231         if (!vma && need_mm) {
 232                 pr_err("%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                 trace_binder_alloc_page_end(alloc, index);
 290                 /* vm_insert_page does not seem to increment the refcount */
 291         }
 292         if (mm) {
 293                 up_write(&mm->mmap_sem);
 294                 mmput(mm);
 295         }
 296         return 0;
 297
 298 free_range:
 299         for (page_addr = end - PAGE_SIZE; page_addr >= start;
 300              page_addr -= PAGE_SIZE) {
 301                 bool ret;
 302                 size_t index;
 303
 304                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 305                 page = &alloc->pages[index];
 306
 307                 trace_binder_free_lru_start(alloc, index);
 308
 309                 ret = list_lru_add(&binder_alloc_lru, &page->lru);
 310                 WARN_ON(!ret);
 311
 312                 trace_binder_free_lru_end(alloc, index);
 313                 continue;
 314
 315 err_vm_insert_page_failed:
 316                 unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
 317 err_map_kernel_failed:
 318                 __free_page(page->page_ptr);
 319                 page->page_ptr = NULL;
 320 err_alloc_page_failed:
 321 err_page_ptr_cleared:
 322                 ;
 323         }
 324 err_no_vma:
 325         if (mm) {
 326                 up_write(&mm->mmap_sem);
 327                 mmput(mm);
 328         }
 329         return vma ? -ENOMEM : -ESRCH;
 330 }
 331
 332 struct binder_buffer *binder_alloc_new_buf_locked(struct binder_alloc *alloc,
 333                                                   size_t data_size,
 334                                                   size_t offsets_size,
 335                                                   size_t extra_buffers_size,
 336                                                   int is_async)
 337 {
 338         struct rb_node *n = alloc->free_buffers.rb_node;
 339         struct binder_buffer *buffer;
 340         size_t buffer_size;
 341         struct rb_node *best_fit = NULL;
 342         void *has_page_addr;
 343         void *end_page_addr;
 344         size_t size, data_offsets_size;
 345         int ret;
 346
 347         if (alloc->vma == NULL) {
 348                 pr_err("%d: binder_alloc_buf, no vma\n",
 349                        alloc->pid);
 350                 return ERR_PTR(-ESRCH);
 351         }
 352
 353         data_offsets_size = ALIGN(data_size, sizeof(void *)) +
 354                 ALIGN(offsets_size, sizeof(void *));
 355
 356         if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
 357                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 358                                 "%d: got transaction with invalid size %zd-%zd\n",
 359                                 alloc->pid, data_size, offsets_size);
 360                 return ERR_PTR(-EINVAL);
 361         }
 362         size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
 363         if (size < data_offsets_size || size < extra_buffers_size) {
 364                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 365                                 "%d: got transaction with invalid extra_buffers_size %zd\n",
 366                                 alloc->pid, extra_buffers_size);
 367                 return ERR_PTR(-EINVAL);
 368         }
 369         if (is_async &&
 370             alloc->free_async_space < size + sizeof(struct binder_buffer)) {
 371                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 372                              "%d: binder_alloc_buf size %zd failed, no async space left\n",
 373                               alloc->pid, size);
 374                 return ERR_PTR(-ENOSPC);
 375         }
 376
 377         /* Pad 0-size buffers so they get assigned unique addresses */
 378         size = max(size, sizeof(void *));
 379
 380         while (n) {
 381                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 382                 BUG_ON(!buffer->free);
 383                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 384
 385                 if (size < buffer_size) {
 386                         best_fit = n;
 387                         n = n->rb_left;
 388                 } else if (size > buffer_size)
 389                         n = n->rb_right;
 390                 else {
 391                         best_fit = n;
 392                         break;
 393                 }
 394         }
 395         if (best_fit == NULL) {
 396                 size_t allocated_buffers = 0;
 397                 size_t largest_alloc_size = 0;
 398                 size_t total_alloc_size = 0;
 399                 size_t free_buffers = 0;
 400                 size_t largest_free_size = 0;
 401                 size_t total_free_size = 0;
 402
 403                 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 404                      n = rb_next(n)) {
 405                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 406                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 407                         allocated_buffers++;
 408                         total_alloc_size += buffer_size;
 409                         if (buffer_size > largest_alloc_size)
 410                                 largest_alloc_size = buffer_size;
 411                 }
 412                 for (n = rb_first(&alloc->free_buffers); n != NULL;
 413                      n = rb_next(n)) {
 414                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 415                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 416                         free_buffers++;
 417                         total_free_size += buffer_size;
 418                         if (buffer_size > largest_free_size)
 419                                 largest_free_size = buffer_size;
 420                 }
 421                 pr_err("%d: binder_alloc_buf size %zd failed, no address space\n",
 422                         alloc->pid, size);
 423                 pr_err("allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
 424                        total_alloc_size, allocated_buffers, largest_alloc_size,
 425                        total_free_size, free_buffers, largest_free_size);
 426                 return ERR_PTR(-ENOSPC);
 427         }
 428         if (n == NULL) {
 429                 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
 430                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 431         }
 432
 433         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 434                      "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
 435                       alloc->pid, size, buffer, buffer_size);
 436
 437         has_page_addr =
 438                 (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK);
 439         WARN_ON(n && buffer_size != size);
 440         end_page_addr =
 441                 (void *)PAGE_ALIGN((uintptr_t)buffer->data + size);
 442         if (end_page_addr > has_page_addr)
 443                 end_page_addr = has_page_addr;
 444         ret = binder_update_page_range(alloc, 1,
 445             (void *)PAGE_ALIGN((uintptr_t)buffer->data), end_page_addr, NULL);
 446         if (ret)
 447                 return ERR_PTR(ret);
 448
 449         if (buffer_size != size) {
 450                 struct binder_buffer *new_buffer;
 451
 452                 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 453                 if (!new_buffer) {
 454                         pr_err("%s: %d failed to alloc new buffer struct\n",
 455                                __func__, alloc->pid);
 456                         goto err_alloc_buf_struct_failed;
 457                 }
 458                 new_buffer->data = (u8 *)buffer->data + size;
 459                 list_add(&new_buffer->entry, &buffer->entry);
 460                 new_buffer->free = 1;
 461                 binder_insert_free_buffer(alloc, new_buffer);
 462         }
 463
 464         rb_erase(best_fit, &alloc->free_buffers);
 465         buffer->free = 0;
 466         buffer->free_in_progress = 0;
 467         binder_insert_allocated_buffer_locked(alloc, buffer);
 468         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 469                      "%d: binder_alloc_buf size %zd got %pK\n",
 470                       alloc->pid, size, buffer);
 471         buffer->data_size = data_size;
 472         buffer->offsets_size = offsets_size;
 473         buffer->async_transaction = is_async;
 474         buffer->extra_buffers_size = extra_buffers_size;
 475         if (is_async) {
 476                 alloc->free_async_space -= size + sizeof(struct binder_buffer);
 477                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 478                              "%d: binder_alloc_buf size %zd async free %zd\n",
 479                               alloc->pid, size, alloc->free_async_space);
 480         }
 481         return buffer;
 482
 483 err_alloc_buf_struct_failed:
 484         binder_update_page_range(alloc, 0,
 485                                  (void *)PAGE_ALIGN((uintptr_t)buffer->data),
 486                                  end_page_addr, NULL);
 487         return ERR_PTR(-ENOMEM);
 488 }
 489
 490 /**
 491  * binder_alloc_new_buf() - Allocate a new binder buffer
 492  * @alloc:              binder_alloc for this proc
 493  * @data_size:          size of user data buffer
 494  * @offsets_size:       user specified buffer offset
 495  * @extra_buffers_size: size of extra space for meta-data (eg, security context)
 496  * @is_async:           buffer for async transaction
 497  *
 498  * Allocate a new buffer given the requested sizes. Returns
 499  * the kernel version of the buffer pointer. The size allocated
 500  * is the sum of the three given sizes (each rounded up to
 501  * pointer-sized boundary)
 502  *
 503  * Return:      The allocated buffer or %NULL if error
 504  */
 505 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 506                                            size_t data_size,
 507                                            size_t offsets_size,
 508                                            size_t extra_buffers_size,
 509                                            int is_async)
 510 {
 511         struct binder_buffer *buffer;
 512
 513         mutex_lock(&alloc->mutex);
 514         buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
 515                                              extra_buffers_size, is_async);
 516         mutex_unlock(&alloc->mutex);
 517         return buffer;
 518 }
 519
 520 static void *buffer_start_page(struct binder_buffer *buffer)
 521 {
 522         return (void *)((uintptr_t)buffer->data & PAGE_MASK);
 523 }
 524
 525 static void *prev_buffer_end_page(struct binder_buffer *buffer)
 526 {
 527         return (void *)(((uintptr_t)(buffer->data) - 1) & PAGE_MASK);
 528 }
 529
 530 static void binder_delete_free_buffer(struct binder_alloc *alloc,
 531                                       struct binder_buffer *buffer)
 532 {
 533         struct binder_buffer *prev, *next = NULL;
 534         bool to_free = true;
 535         BUG_ON(alloc->buffers.next == &buffer->entry);
 536         prev = binder_buffer_prev(buffer);
 537         BUG_ON(!prev->free);
 538         if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
 539                 to_free = false;
 540                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 541                                    "%d: merge free, buffer %pK share page with %pK\n",
 542                                    alloc->pid, buffer->data, prev->data);
 543         }
 544
 545         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 546                 next = binder_buffer_next(buffer);
 547                 if (buffer_start_page(next) == buffer_start_page(buffer)) {
 548                         to_free = false;
 549                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 550                                            "%d: merge free, buffer %pK share page with %pK\n",
 551                                            alloc->pid,
 552                                            buffer->data,
 553                                            next->data);
 554                 }
 555         }
 556
 557         if (PAGE_ALIGNED(buffer->data)) {
 558                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 559                                    "%d: merge free, buffer start %pK is page aligned\n",
 560                                    alloc->pid, buffer->data);
 561                 to_free = false;
 562         }
 563
 564         if (to_free) {
 565                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 566                                    "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
 567                                    alloc->pid, buffer->data,
 568                                    prev->data, next->data);
 569                 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
 570                                          buffer_start_page(buffer) + PAGE_SIZE,
 571                                          NULL);
 572         }
 573         list_del(&buffer->entry);
 574         kfree(buffer);
 575 }
 576
 577 static void binder_free_buf_locked(struct binder_alloc *alloc,
 578                                    struct binder_buffer *buffer)
 579 {
 580         size_t size, buffer_size;
 581
 582         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 583
 584         size = ALIGN(buffer->data_size, sizeof(void *)) +
 585                 ALIGN(buffer->offsets_size, sizeof(void *)) +
 586                 ALIGN(buffer->extra_buffers_size, sizeof(void *));
 587
 588         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 589                      "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
 590                       alloc->pid, buffer, size, buffer_size);
 591
 592         BUG_ON(buffer->free);
 593         BUG_ON(size > buffer_size);
 594         BUG_ON(buffer->transaction != NULL);
 595         BUG_ON(buffer->data < alloc->buffer);
 596         BUG_ON(buffer->data > alloc->buffer + alloc->buffer_size);
 597
 598         if (buffer->async_transaction) {
 599                 alloc->free_async_space += size + sizeof(struct binder_buffer);
 600
 601                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 602                              "%d: binder_free_buf size %zd async free %zd\n",
 603                               alloc->pid, size, alloc->free_async_space);
 604         }
 605
 606         binder_update_page_range(alloc, 0,
 607                 (void *)PAGE_ALIGN((uintptr_t)buffer->data),
 608                 (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK),
 609                 NULL);
 610
 611         rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
 612         buffer->free = 1;
 613         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 614                 struct binder_buffer *next = binder_buffer_next(buffer);
 615
 616                 if (next->free) {
 617                         rb_erase(&next->rb_node, &alloc->free_buffers);
 618                         binder_delete_free_buffer(alloc, next);
 619                 }
 620         }
 621         if (alloc->buffers.next != &buffer->entry) {
 622                 struct binder_buffer *prev = binder_buffer_prev(buffer);
 623
 624                 if (prev->free) {
 625                         binder_delete_free_buffer(alloc, buffer);
 626                         rb_erase(&prev->rb_node, &alloc->free_buffers);
 627                         buffer = prev;
 628                 }
 629         }
 630         binder_insert_free_buffer(alloc, buffer);
 631 }
 632
 633 /**
 634  * binder_alloc_free_buf() - free a binder buffer
 635  * @alloc:      binder_alloc for this proc
 636  * @buffer:     kernel pointer to buffer
 637  *
 638  * Free the buffer allocated via binder_alloc_new_buffer()
 639  */
 640 void binder_alloc_free_buf(struct binder_alloc *alloc,
 641                             struct binder_buffer *buffer)
 642 {
 643         mutex_lock(&alloc->mutex);
 644         binder_free_buf_locked(alloc, buffer);
 645         mutex_unlock(&alloc->mutex);
 646 }
 647
 648 /**
 649  * binder_alloc_mmap_handler() - map virtual address space for proc
 650  * @alloc:      alloc structure for this proc
 651  * @vma:        vma passed to mmap()
 652  *
 653  * Called by binder_mmap() to initialize the space specified in
 654  * vma for allocating binder buffers
 655  *
 656  * Return:
 657  *      0 = success
 658  *      -EBUSY = address space already mapped
 659  *      -ENOMEM = failed to map memory to given address space
 660  */
 661 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 662                               struct vm_area_struct *vma)
 663 {
 664         int ret;
 665         struct vm_struct *area;
 666         const char *failure_string;
 667         struct binder_buffer *buffer;
 668
 669         mutex_lock(&binder_alloc_mmap_lock);
 670         if (alloc->buffer) {
 671                 ret = -EBUSY;
 672                 failure_string = "already mapped";
 673                 goto err_already_mapped;
 674         }
 675
 676         area = get_vm_area(vma->vm_end - vma->vm_start, VM_IOREMAP);
 677         if (area == NULL) {
 678                 ret = -ENOMEM;
 679                 failure_string = "get_vm_area";
 680                 goto err_get_vm_area_failed;
 681         }
 682         alloc->buffer = area->addr;
 683         alloc->user_buffer_offset =
 684                 vma->vm_start - (uintptr_t)alloc->buffer;
 685         mutex_unlock(&binder_alloc_mmap_lock);
 686
 687 #ifdef CONFIG_CPU_CACHE_VIPT
 688         if (cache_is_vipt_aliasing()) {
 689                 while (CACHE_COLOUR(
 690                                 (vma->vm_start ^ (uint32_t)alloc->buffer))) {
 691                         pr_info("%s: %d %lx-%lx maps %pK bad alignment\n",
 692                                 __func__, alloc->pid, vma->vm_start,
 693                                 vma->vm_end, alloc->buffer);
 694                         vma->vm_start += PAGE_SIZE;
 695                 }
 696         }
 697 #endif
 698         alloc->pages = kzalloc(sizeof(alloc->pages[0]) *
 699                                    ((vma->vm_end - vma->vm_start) / PAGE_SIZE),
 700                                GFP_KERNEL);
 701         if (alloc->pages == NULL) {
 702                 ret = -ENOMEM;
 703                 failure_string = "alloc page array";
 704                 goto err_alloc_pages_failed;
 705         }
 706         alloc->buffer_size = vma->vm_end - vma->vm_start;
 707
 708         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 709         if (!buffer) {
 710                 ret = -ENOMEM;
 711                 failure_string = "alloc buffer struct";
 712                 goto err_alloc_buf_struct_failed;
 713         }
 714
 715         buffer->data = alloc->buffer;
 716         list_add(&buffer->entry, &alloc->buffers);
 717         buffer->free = 1;
 718         binder_insert_free_buffer(alloc, buffer);
 719         alloc->free_async_space = alloc->buffer_size / 2;
 720         barrier();
 721         alloc->vma = vma;
 722         alloc->vma_vm_mm = vma->vm_mm;
 723
 724         return 0;
 725
 726 err_alloc_buf_struct_failed:
 727         kfree(alloc->pages);
 728         alloc->pages = NULL;
 729 err_alloc_pages_failed:
 730         mutex_lock(&binder_alloc_mmap_lock);
 731         vfree(alloc->buffer);
 732         alloc->buffer = NULL;
 733 err_get_vm_area_failed:
 734 err_already_mapped:
 735         mutex_unlock(&binder_alloc_mmap_lock);
 736         pr_err("%s: %d %lx-%lx %s failed %d\n", __func__,
 737                alloc->pid, vma->vm_start, vma->vm_end, failure_string, ret);
 738         return ret;
 739 }
 740
 741
 742 void binder_alloc_deferred_release(struct binder_alloc *alloc)
 743 {
 744         struct rb_node *n;
 745         int buffers, page_count;
 746         struct binder_buffer *buffer;
 747
 748         BUG_ON(alloc->vma);
 749
 750         buffers = 0;
 751         mutex_lock(&alloc->mutex);
 752         while ((n = rb_first(&alloc->allocated_buffers))) {
 753                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 754
 755                 /* Transaction should already have been freed */
 756                 BUG_ON(buffer->transaction);
 757
 758                 binder_free_buf_locked(alloc, buffer);
 759                 buffers++;
 760         }
 761
 762         while (!list_empty(&alloc->buffers)) {
 763                 buffer = list_first_entry(&alloc->buffers,
 764                                           struct binder_buffer, entry);
 765                 WARN_ON(!buffer->free);
 766
 767                 list_del(&buffer->entry);
 768                 WARN_ON_ONCE(!list_empty(&alloc->buffers));
 769                 kfree(buffer);
 770         }
 771
 772         page_count = 0;
 773         if (alloc->pages) {
 774                 int i;
 775
 776                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 777                         void *page_addr;
 778                         bool on_lru;
 779
 780                         if (!alloc->pages[i].page_ptr)
 781                                 continue;
 782
 783                         on_lru = list_lru_del(&binder_alloc_lru,
 784                                               &alloc->pages[i].lru);
 785                         page_addr = alloc->buffer + i * PAGE_SIZE;
 786                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 787                                      "%s: %d: page %d at %pK %s\n",
 788                                      __func__, alloc->pid, i, page_addr,
 789                                      on_lru ? "on lru" : "active");
 790                         unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
 791                         __free_page(alloc->pages[i].page_ptr);
 792                         page_count++;
 793                 }
 794                 kfree(alloc->pages);
 795                 vfree(alloc->buffer);
 796         }
 797         mutex_unlock(&alloc->mutex);
 798
 799         binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
 800                      "%s: %d buffers %d, pages %d\n",
 801                      __func__, alloc->pid, buffers, page_count);
 802 }
 803
 804 static void print_binder_buffer(struct seq_file *m, const char *prefix,
 805                                 struct binder_buffer *buffer)
 806 {
 807         seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
 808                    prefix, buffer->debug_id, buffer->data,
 809                    buffer->data_size, buffer->offsets_size,
 810                    buffer->extra_buffers_size,
 811                    buffer->transaction ? "active" : "delivered");
 812 }
 813
 814 /**
 815  * binder_alloc_print_allocated() - print buffer info
 816  * @m:     seq_file for output via seq_printf()
 817  * @alloc: binder_alloc for this proc
 818  *
 819  * Prints information about every buffer associated with
 820  * the binder_alloc state to the given seq_file
 821  */
 822 void binder_alloc_print_allocated(struct seq_file *m,
 823                                   struct binder_alloc *alloc)
 824 {
 825         struct rb_node *n;
 826
 827         mutex_lock(&alloc->mutex);
 828         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 829                 print_binder_buffer(m, "  buffer",
 830                                     rb_entry(n, struct binder_buffer, rb_node));
 831         mutex_unlock(&alloc->mutex);
 832 }
 833
 834 /**
 835  * binder_alloc_print_pages() - print page usage
 836  * @m:     seq_file for output via seq_printf()
 837  * @alloc: binder_alloc for this proc
 838  */
 839 void binder_alloc_print_pages(struct seq_file *m,
 840                               struct binder_alloc *alloc)
 841 {
 842         struct binder_lru_page *page;
 843         int i;
 844         int active = 0;
 845         int lru = 0;
 846         int free = 0;
 847
 848         mutex_lock(&alloc->mutex);
 849         for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 850                 page = &alloc->pages[i];
 851                 if (!page->page_ptr)
 852                         free++;
 853                 else if (list_empty(&page->lru))
 854                         active++;
 855                 else
 856                         lru++;
 857         }
 858         mutex_unlock(&alloc->mutex);
 859         seq_printf(m, "  pages: %d:%d:%d\n", active, lru, free);
 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         WRITE_ONCE(alloc->vma_vm_mm, NULL);
 893 }
 894
 895 /**
 896  * binder_alloc_free_page() - shrinker callback to free pages
 897  * @item:   item to free
 898  * @lock:   lock protecting the item
 899  * @cb_arg: callback argument
 900  *
 901  * Called from list_lru_walk() in binder_shrink_scan() to free
 902  * up pages when the system is under memory pressure.
 903  */
 904 enum lru_status binder_alloc_free_page(struct list_head *item,
 905                                        struct list_lru_one *lru,
 906                                        spinlock_t *lock,
 907                                        void *cb_arg)
 908 {
 909         struct mm_struct *mm = NULL;
 910         struct binder_lru_page *page = container_of(item,
 911                                                     struct binder_lru_page,
 912                                                     lru);
 913         struct binder_alloc *alloc;
 914         uintptr_t page_addr;
 915         size_t index;
 916         struct vm_area_struct *vma;
 917
 918         alloc = page->alloc;
 919         if (!mutex_trylock(&alloc->mutex))
 920                 goto err_get_alloc_mutex_failed;
 921
 922         if (!page->page_ptr)
 923                 goto err_page_already_freed;
 924
 925         index = page - alloc->pages;
 926         page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
 927         vma = alloc->vma;
 928         if (vma) {
 929                 mm = get_task_mm(alloc->tsk);
 930                 if (!mm)
 931                         goto err_get_task_mm_failed;
 932                 if (!down_write_trylock(&mm->mmap_sem))
 933                         goto err_down_write_mmap_sem_failed;
 934         }
 935
 936         list_lru_isolate(lru, item);
 937         spin_unlock(lock);
 938
 939         if (vma) {
 940                 trace_binder_unmap_user_start(alloc, index);
 941
 942                 zap_page_range(vma,
 943                                page_addr + alloc->user_buffer_offset,
 944                                PAGE_SIZE);
 945
 946                 trace_binder_unmap_user_end(alloc, index);
 947
 948                 up_write(&mm->mmap_sem);
 949                 mmput(mm);
 950         }
 951
 952         trace_binder_unmap_kernel_start(alloc, index);
 953
 954         unmap_kernel_range(page_addr, PAGE_SIZE);
 955         __free_page(page->page_ptr);
 956         page->page_ptr = NULL;
 957
 958         trace_binder_unmap_kernel_end(alloc, index);
 959
 960         spin_lock(lock);
 961         mutex_unlock(&alloc->mutex);
 962         return LRU_REMOVED_RETRY;
 963
 964 err_down_write_mmap_sem_failed:
 965         mmput_async(mm);
 966 err_get_task_mm_failed:
 967 err_page_already_freed:
 968         mutex_unlock(&alloc->mutex);
 969 err_get_alloc_mutex_failed:
 970         return LRU_SKIP;
 971 }
 972
 973 static unsigned long
 974 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 975 {
 976         unsigned long ret = list_lru_count(&binder_alloc_lru);
 977         return ret;
 978 }
 979
 980 static unsigned long
 981 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 982 {
 983         unsigned long ret;
 984
 985         ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
 986                             NULL, sc->nr_to_scan);
 987         return ret;
 988 }
 989
 990 struct shrinker binder_shrinker = {
 991         .count_objects = binder_shrink_count,
 992         .scan_objects = binder_shrink_scan,
 993         .seeks = DEFAULT_SEEKS,
 994 };
 995
 996 /**
 997  * binder_alloc_init() - called by binder_open() for per-proc initialization
 998  * @alloc: binder_alloc for this proc
 999  *
1000  * Called from binder_open() to initialize binder_alloc fields for
1001  * new binder proc
1002  */
1003 void binder_alloc_init(struct binder_alloc *alloc)
1004 {
1005         alloc->tsk = current->group_leader;
1006         alloc->pid = current->group_leader->pid;
1007         mutex_init(&alloc->mutex);
1008         INIT_LIST_HEAD(&alloc->buffers);
1009 }
1010
1011 void binder_alloc_shrinker_init(void)
1012 {
1013         list_lru_init(&binder_alloc_lru);
1014         register_shrinker(&binder_shrinker);
1015 }