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