drivers/android/binder_alloc.c

   1 /* binder_alloc.c
   2  *
   3  * Android IPC Subsystem
   4  *
   5  * Copyright (C) 2007-2017 Google, Inc.
   6  *
   7  * This software is licensed under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation, and
   9  * may be copied, distributed, and modified under those terms.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  */
  17
  18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  19
  20 #include <linux/list.h>
  21 #include <linux/sched/mm.h>
  22 #include <linux/module.h>
  23 #include <linux/rtmutex.h>
  24 #include <linux/rbtree.h>
  25 #include <linux/seq_file.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/slab.h>
  28 #include <linux/sched.h>
  29 #include <linux/list_lru.h>
  30 #include <linux/ratelimit.h>
  31 #include <asm/cacheflush.h>
  32 #include <linux/uaccess.h>
  33 #include <linux/highmem.h>
  34 #include "binder_alloc.h"
  35 #include "binder_trace.h"
  36
  37 struct list_lru binder_alloc_lru;
  38
  39 static DEFINE_MUTEX(binder_alloc_mmap_lock);
  40
  41 enum {
  42         BINDER_DEBUG_USER_ERROR             = 1U << 0,
  43         BINDER_DEBUG_OPEN_CLOSE             = 1U << 1,
  44         BINDER_DEBUG_BUFFER_ALLOC           = 1U << 2,
  45         BINDER_DEBUG_BUFFER_ALLOC_ASYNC     = 1U << 3,
  46 };
  47 static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
  48
  49 module_param_named(debug_mask, binder_alloc_debug_mask,
  50                    uint, 0644);
  51
  52 #define binder_alloc_debug(mask, x...) \
  53         do { \
  54                 if (binder_alloc_debug_mask & mask) \
  55                         pr_info_ratelimited(x); \
  56         } while (0)
  57
  58 static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
  59 {
  60         return list_entry(buffer->entry.next, struct binder_buffer, entry);
  61 }
  62
  63 static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
  64 {
  65         return list_entry(buffer->entry.prev, struct binder_buffer, entry);
  66 }
  67
  68 static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
  69                                        struct binder_buffer *buffer)
  70 {
  71         if (list_is_last(&buffer->entry, &alloc->buffers))
  72                 return alloc->buffer + alloc->buffer_size - buffer->user_data;
  73         return binder_buffer_next(buffer)->user_data - buffer->user_data;
  74 }
  75
  76 static void binder_insert_free_buffer(struct binder_alloc *alloc,
  77                                       struct binder_buffer *new_buffer)
  78 {
  79         struct rb_node **p = &alloc->free_buffers.rb_node;
  80         struct rb_node *parent = NULL;
  81         struct binder_buffer *buffer;
  82         size_t buffer_size;
  83         size_t new_buffer_size;
  84
  85         BUG_ON(!new_buffer->free);
  86
  87         new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
  88
  89         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
  90                      "%d: add free buffer, size %zd, at %pK\n",
  91                       alloc->pid, new_buffer_size, new_buffer);
  92
  93         while (*p) {
  94                 parent = *p;
  95                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
  96                 BUG_ON(!buffer->free);
  97
  98                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
  99
 100                 if (new_buffer_size < buffer_size)
 101                         p = &parent->rb_left;
 102                 else
 103                         p = &parent->rb_right;
 104         }
 105         rb_link_node(&new_buffer->rb_node, parent, p);
 106         rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
 107 }
 108
 109 static void binder_insert_allocated_buffer_locked(
 110                 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
 111 {
 112         struct rb_node **p = &alloc->allocated_buffers.rb_node;
 113         struct rb_node *parent = NULL;
 114         struct binder_buffer *buffer;
 115
 116         BUG_ON(new_buffer->free);
 117
 118         while (*p) {
 119                 parent = *p;
 120                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
 121                 BUG_ON(buffer->free);
 122
 123                 if (new_buffer->user_data < buffer->user_data)
 124                         p = &parent->rb_left;
 125                 else if (new_buffer->user_data > buffer->user_data)
 126                         p = &parent->rb_right;
 127                 else
 128                         BUG();
 129         }
 130         rb_link_node(&new_buffer->rb_node, parent, p);
 131         rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
 132 }
 133
 134 static struct binder_buffer *binder_alloc_prepare_to_free_locked(
 135                 struct binder_alloc *alloc,
 136                 uintptr_t user_ptr)
 137 {
 138         struct rb_node *n = alloc->allocated_buffers.rb_node;
 139         struct binder_buffer *buffer;
 140         void __user *uptr;
 141
 142         uptr = (void __user *)user_ptr;
 143
 144         while (n) {
 145                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 146                 BUG_ON(buffer->free);
 147
 148                 if (uptr < buffer->user_data)
 149                         n = n->rb_left;
 150                 else if (uptr > buffer->user_data)
 151                         n = n->rb_right;
 152                 else {
 153                         /*
 154                          * Guard against user threads attempting to
 155                          * free the buffer when in use by kernel or
 156                          * after it's already been freed.
 157                          */
 158                         if (!buffer->allow_user_free)
 159                                 return ERR_PTR(-EPERM);
 160                         buffer->allow_user_free = 0;
 161                         return buffer;
 162                 }
 163         }
 164         return NULL;
 165 }
 166
 167 /**
 168  * binder_alloc_buffer_lookup() - get buffer given user ptr
 169  * @alloc:      binder_alloc for this proc
 170  * @user_ptr:   User pointer to buffer data
 171  *
 172  * Validate userspace pointer to buffer data and return buffer corresponding to
 173  * that user pointer. Search the rb tree for buffer that matches user data
 174  * pointer.
 175  *
 176  * Return:      Pointer to buffer or NULL
 177  */
 178 struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
 179                                                    uintptr_t user_ptr)
 180 {
 181         struct binder_buffer *buffer;
 182
 183         mutex_lock(&alloc->mutex);
 184         buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
 185         mutex_unlock(&alloc->mutex);
 186         return buffer;
 187 }
 188
 189 static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
 190                                     void __user *start, void __user *end)
 191 {
 192         void __user *page_addr;
 193         unsigned long user_page_addr;
 194         struct binder_lru_page *page;
 195         struct vm_area_struct *vma = NULL;
 196         struct mm_struct *mm = NULL;
 197         bool need_mm = false;
 198
 199         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 200                      "%d: %s pages %pK-%pK\n", alloc->pid,
 201                      allocate ? "allocate" : "free", start, end);
 202
 203         if (end <= start)
 204                 return 0;
 205
 206         trace_binder_update_page_range(alloc, allocate, start, end);
 207
 208         if (allocate == 0)
 209                 goto free_range;
 210
 211         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 212                 page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
 213                 if (!page->page_ptr) {
 214                         need_mm = true;
 215                         break;
 216                 }
 217         }
 218
 219         if (need_mm && mmget_not_zero(alloc->vma_vm_mm))
 220                 mm = alloc->vma_vm_mm;
 221
 222         if (mm) {
 223                 down_read(&mm->mmap_sem);
 224                 vma = alloc->vma;
 225         }
 226
 227         if (!vma && need_mm) {
 228                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 229                                    "%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
 230                                    alloc->pid);
 231                 goto err_no_vma;
 232         }
 233
 234         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 235                 int ret;
 236                 bool on_lru;
 237                 size_t index;
 238
 239                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 240                 page = &alloc->pages[index];
 241
 242                 if (page->page_ptr) {
 243                         trace_binder_alloc_lru_start(alloc, index);
 244
 245                         on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
 246                         WARN_ON(!on_lru);
 247
 248                         trace_binder_alloc_lru_end(alloc, index);
 249                         continue;
 250                 }
 251
 252                 if (WARN_ON(!vma))
 253                         goto err_page_ptr_cleared;
 254
 255                 trace_binder_alloc_page_start(alloc, index);
 256                 page->page_ptr = alloc_page(GFP_KERNEL |
 257                                             __GFP_HIGHMEM |
 258                                             __GFP_ZERO);
 259                 if (!page->page_ptr) {
 260                         pr_err("%d: binder_alloc_buf failed for page at %pK\n",
 261                                 alloc->pid, page_addr);
 262                         goto err_alloc_page_failed;
 263                 }
 264                 page->alloc = alloc;
 265                 INIT_LIST_HEAD(&page->lru);
 266
 267                 user_page_addr = (uintptr_t)page_addr;
 268                 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
 269                 if (ret) {
 270                         pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
 271                                alloc->pid, user_page_addr);
 272                         goto err_vm_insert_page_failed;
 273                 }
 274
 275                 if (index + 1 > alloc->pages_high)
 276                         alloc->pages_high = index + 1;
 277
 278                 trace_binder_alloc_page_end(alloc, index);
 279                 /* vm_insert_page does not seem to increment the refcount */
 280         }
 281         if (mm) {
 282                 up_read(&mm->mmap_sem);
 283                 mmput(mm);
 284         }
 285         return 0;
 286
 287 free_range:
 288         for (page_addr = end - PAGE_SIZE; page_addr >= start;
 289              page_addr -= PAGE_SIZE) {
 290                 bool ret;
 291                 size_t index;
 292
 293                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 294                 page = &alloc->pages[index];
 295
 296                 trace_binder_free_lru_start(alloc, index);
 297
 298                 ret = list_lru_add(&binder_alloc_lru, &page->lru);
 299                 WARN_ON(!ret);
 300
 301                 trace_binder_free_lru_end(alloc, index);
 302                 continue;
 303
 304 err_vm_insert_page_failed:
 305                 __free_page(page->page_ptr);
 306                 page->page_ptr = NULL;
 307 err_alloc_page_failed:
 308 err_page_ptr_cleared:
 309                 ;
 310         }
 311 err_no_vma:
 312         if (mm) {
 313                 up_read(&mm->mmap_sem);
 314                 mmput(mm);
 315         }
 316         return vma ? -ENOMEM : -ESRCH;
 317 }
 318
 319
 320 static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
 321                 struct vm_area_struct *vma)
 322 {
 323         if (vma)
 324                 alloc->vma_vm_mm = vma->vm_mm;
 325         /*
 326          * If we see alloc->vma is not NULL, buffer data structures set up
 327          * completely. Look at smp_rmb side binder_alloc_get_vma.
 328          * We also want to guarantee new alloc->vma_vm_mm is always visible
 329          * if alloc->vma is set.
 330          */
 331         smp_wmb();
 332         alloc->vma = vma;
 333 }
 334
 335 static inline struct vm_area_struct *binder_alloc_get_vma(
 336                 struct binder_alloc *alloc)
 337 {
 338         struct vm_area_struct *vma = NULL;
 339
 340         if (alloc->vma) {
 341                 /* Look at description in binder_alloc_set_vma */
 342                 smp_rmb();
 343                 vma = alloc->vma;
 344         }
 345         return vma;
 346 }
 347
 348 static struct binder_buffer *binder_alloc_new_buf_locked(
 349                                 struct binder_alloc *alloc,
 350                                 size_t data_size,
 351                                 size_t offsets_size,
 352                                 size_t extra_buffers_size,
 353                                 int is_async)
 354 {
 355         struct rb_node *n = alloc->free_buffers.rb_node;
 356         struct binder_buffer *buffer;
 357         size_t buffer_size;
 358         struct rb_node *best_fit = NULL;
 359         void __user *has_page_addr;
 360         void __user *end_page_addr;
 361         size_t size, data_offsets_size;
 362         int ret;
 363
 364         if (!binder_alloc_get_vma(alloc)) {
 365                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 366                                    "%d: binder_alloc_buf, no vma\n",
 367                                    alloc->pid);
 368                 return ERR_PTR(-ESRCH);
 369         }
 370
 371         data_offsets_size = ALIGN(data_size, sizeof(void *)) +
 372                 ALIGN(offsets_size, sizeof(void *));
 373
 374         if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
 375                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 376                                 "%d: got transaction with invalid size %zd-%zd\n",
 377                                 alloc->pid, data_size, offsets_size);
 378                 return ERR_PTR(-EINVAL);
 379         }
 380         size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
 381         if (size < data_offsets_size || size < extra_buffers_size) {
 382                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 383                                 "%d: got transaction with invalid extra_buffers_size %zd\n",
 384                                 alloc->pid, extra_buffers_size);
 385                 return ERR_PTR(-EINVAL);
 386         }
 387         if (is_async &&
 388             alloc->free_async_space < size + sizeof(struct binder_buffer)) {
 389                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 390                              "%d: binder_alloc_buf size %zd failed, no async space left\n",
 391                               alloc->pid, size);
 392                 return ERR_PTR(-ENOSPC);
 393         }
 394
 395         /* Pad 0-size buffers so they get assigned unique addresses */
 396         size = max(size, sizeof(void *));
 397
 398         while (n) {
 399                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 400                 BUG_ON(!buffer->free);
 401                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 402
 403                 if (size < buffer_size) {
 404                         best_fit = n;
 405                         n = n->rb_left;
 406                 } else if (size > buffer_size)
 407                         n = n->rb_right;
 408                 else {
 409                         best_fit = n;
 410                         break;
 411                 }
 412         }
 413         if (best_fit == NULL) {
 414                 size_t allocated_buffers = 0;
 415                 size_t largest_alloc_size = 0;
 416                 size_t total_alloc_size = 0;
 417                 size_t free_buffers = 0;
 418                 size_t largest_free_size = 0;
 419                 size_t total_free_size = 0;
 420
 421                 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 422                      n = rb_next(n)) {
 423                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 424                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 425                         allocated_buffers++;
 426                         total_alloc_size += buffer_size;
 427                         if (buffer_size > largest_alloc_size)
 428                                 largest_alloc_size = buffer_size;
 429                 }
 430                 for (n = rb_first(&alloc->free_buffers); n != NULL;
 431                      n = rb_next(n)) {
 432                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 433                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 434                         free_buffers++;
 435                         total_free_size += buffer_size;
 436                         if (buffer_size > largest_free_size)
 437                                 largest_free_size = buffer_size;
 438                 }
 439                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 440                                    "%d: binder_alloc_buf size %zd failed, no address space\n",
 441                                    alloc->pid, size);
 442                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 443                                    "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
 444                                    total_alloc_size, allocated_buffers,
 445                                    largest_alloc_size, total_free_size,
 446                                    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 = (void __user *)
 459                 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
 460         WARN_ON(n && buffer_size != size);
 461         end_page_addr =
 462                 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_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, (void __user *)
 466                 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
 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->user_data = (u8 __user *)buffer->user_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, (void __user *)
 506                                  PAGE_ALIGN((uintptr_t)buffer->user_data),
 507                                  end_page_addr);
 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 __user *buffer_start_page(struct binder_buffer *buffer)
 542 {
 543         return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
 544 }
 545
 546 static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
 547 {
 548         return (void __user *)
 549                 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
 550 }
 551
 552 static void binder_delete_free_buffer(struct binder_alloc *alloc,
 553                                       struct binder_buffer *buffer)
 554 {
 555         struct binder_buffer *prev, *next = NULL;
 556         bool to_free = true;
 557         BUG_ON(alloc->buffers.next == &buffer->entry);
 558         prev = binder_buffer_prev(buffer);
 559         BUG_ON(!prev->free);
 560         if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
 561                 to_free = false;
 562                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 563                                    "%d: merge free, buffer %pK share page with %pK\n",
 564                                    alloc->pid, buffer->user_data,
 565                                    prev->user_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->user_data,
 576                                            next->user_data);
 577                 }
 578         }
 579
 580         if (PAGE_ALIGNED(buffer->user_data)) {
 581                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 582                                    "%d: merge free, buffer start %pK is page aligned\n",
 583                                    alloc->pid, buffer->user_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->user_data,
 591                                    prev->user_data,
 592                                    next ? next->user_data : NULL);
 593                 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
 594                                          buffer_start_page(buffer) + PAGE_SIZE);
 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->user_data < alloc->buffer);
 619         BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
 620
 621         if (buffer->async_transaction) {
 622                 alloc->free_async_space += 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 __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
 631                 (void __user *)(((uintptr_t)
 632                           buffer->user_data + buffer_size) & PAGE_MASK));
 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         const char *failure_string;
 689         struct binder_buffer *buffer;
 690
 691         mutex_lock(&binder_alloc_mmap_lock);
 692         if (alloc->buffer) {
 693                 ret = -EBUSY;
 694                 failure_string = "already mapped";
 695                 goto err_already_mapped;
 696         }
 697
 698         alloc->buffer = (void __user *)vma->vm_start;
 699         mutex_unlock(&binder_alloc_mmap_lock);
 700
 701         alloc->pages = kcalloc((vma->vm_end - vma->vm_start) / PAGE_SIZE,
 702                                sizeof(alloc->pages[0]),
 703                                GFP_KERNEL);
 704         if (alloc->pages == NULL) {
 705                 ret = -ENOMEM;
 706                 failure_string = "alloc page array";
 707                 goto err_alloc_pages_failed;
 708         }
 709         alloc->buffer_size = vma->vm_end - vma->vm_start;
 710
 711         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 712         if (!buffer) {
 713                 ret = -ENOMEM;
 714                 failure_string = "alloc buffer struct";
 715                 goto err_alloc_buf_struct_failed;
 716         }
 717
 718         buffer->user_data = alloc->buffer;
 719         list_add(&buffer->entry, &alloc->buffers);
 720         buffer->free = 1;
 721         binder_insert_free_buffer(alloc, buffer);
 722         alloc->free_async_space = alloc->buffer_size / 2;
 723         binder_alloc_set_vma(alloc, vma);
 724         mmgrab(alloc->vma_vm_mm);
 725
 726         return 0;
 727
 728 err_alloc_buf_struct_failed:
 729         kfree(alloc->pages);
 730         alloc->pages = NULL;
 731 err_alloc_pages_failed:
 732         mutex_lock(&binder_alloc_mmap_lock);
 733         alloc->buffer = NULL;
 734 err_already_mapped:
 735         mutex_unlock(&binder_alloc_mmap_lock);
 736         binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 737                            "%s: %d %lx-%lx %s failed %d\n", __func__,
 738                            alloc->pid, vma->vm_start, vma->vm_end,
 739                            failure_string, ret);
 740         return ret;
 741 }
 742
 743
 744 void binder_alloc_deferred_release(struct binder_alloc *alloc)
 745 {
 746         struct rb_node *n;
 747         int buffers, page_count;
 748         struct binder_buffer *buffer;
 749
 750         buffers = 0;
 751         mutex_lock(&alloc->mutex);
 752         BUG_ON(alloc->vma);
 753
 754         while ((n = rb_first(&alloc->allocated_buffers))) {
 755                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 756
 757                 /* Transaction should already have been freed */
 758                 BUG_ON(buffer->transaction);
 759
 760                 binder_free_buf_locked(alloc, buffer);
 761                 buffers++;
 762         }
 763
 764         while (!list_empty(&alloc->buffers)) {
 765                 buffer = list_first_entry(&alloc->buffers,
 766                                           struct binder_buffer, entry);
 767                 WARN_ON(!buffer->free);
 768
 769                 list_del(&buffer->entry);
 770                 WARN_ON_ONCE(!list_empty(&alloc->buffers));
 771                 kfree(buffer);
 772         }
 773
 774         page_count = 0;
 775         if (alloc->pages) {
 776                 int i;
 777
 778                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 779                         void __user *page_addr;
 780                         bool on_lru;
 781
 782                         if (!alloc->pages[i].page_ptr)
 783                                 continue;
 784
 785                         on_lru = list_lru_del(&binder_alloc_lru,
 786                                               &alloc->pages[i].lru);
 787                         page_addr = alloc->buffer + i * PAGE_SIZE;
 788                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 789                                      "%s: %d: page %d at %pK %s\n",
 790                                      __func__, alloc->pid, i, page_addr,
 791                                      on_lru ? "on lru" : "active");
 792                         __free_page(alloc->pages[i].page_ptr);
 793                         page_count++;
 794                 }
 795                 kfree(alloc->pages);
 796         }
 797         mutex_unlock(&alloc->mutex);
 798         if (alloc->vma_vm_mm)
 799                 mmdrop(alloc->vma_vm_mm);
 800
 801         binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
 802                      "%s: %d buffers %d, pages %d\n",
 803                      __func__, alloc->pid, buffers, page_count);
 804 }
 805
 806 static void print_binder_buffer(struct seq_file *m, const char *prefix,
 807                                 struct binder_buffer *buffer)
 808 {
 809         seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
 810                    prefix, buffer->debug_id, buffer->user_data,
 811                    buffer->data_size, buffer->offsets_size,
 812                    buffer->extra_buffers_size,
 813                    buffer->transaction ? "active" : "delivered");
 814 }
 815
 816 /**
 817  * binder_alloc_print_allocated() - print buffer info
 818  * @m:     seq_file for output via seq_printf()
 819  * @alloc: binder_alloc for this proc
 820  *
 821  * Prints information about every buffer associated with
 822  * the binder_alloc state to the given seq_file
 823  */
 824 void binder_alloc_print_allocated(struct seq_file *m,
 825                                   struct binder_alloc *alloc)
 826 {
 827         struct rb_node *n;
 828
 829         mutex_lock(&alloc->mutex);
 830         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 831                 print_binder_buffer(m, "  buffer",
 832                                     rb_entry(n, struct binder_buffer, rb_node));
 833         mutex_unlock(&alloc->mutex);
 834 }
 835
 836 /**
 837  * binder_alloc_print_pages() - print page usage
 838  * @m:     seq_file for output via seq_printf()
 839  * @alloc: binder_alloc for this proc
 840  */
 841 void binder_alloc_print_pages(struct seq_file *m,
 842                               struct binder_alloc *alloc)
 843 {
 844         struct binder_lru_page *page;
 845         int i;
 846         int active = 0;
 847         int lru = 0;
 848         int free = 0;
 849
 850         mutex_lock(&alloc->mutex);
 851         for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 852                 page = &alloc->pages[i];
 853                 if (!page->page_ptr)
 854                         free++;
 855                 else if (list_empty(&page->lru))
 856                         active++;
 857                 else
 858                         lru++;
 859         }
 860         mutex_unlock(&alloc->mutex);
 861         seq_printf(m, "  pages: %d:%d:%d\n", active, lru, free);
 862         seq_printf(m, "  pages high watermark: %zu\n", alloc->pages_high);
 863 }
 864
 865 /**
 866  * binder_alloc_get_allocated_count() - return count of buffers
 867  * @alloc: binder_alloc for this proc
 868  *
 869  * Return: count of allocated buffers
 870  */
 871 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
 872 {
 873         struct rb_node *n;
 874         int count = 0;
 875
 876         mutex_lock(&alloc->mutex);
 877         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 878                 count++;
 879         mutex_unlock(&alloc->mutex);
 880         return count;
 881 }
 882
 883
 884 /**
 885  * binder_alloc_vma_close() - invalidate address space
 886  * @alloc: binder_alloc for this proc
 887  *
 888  * Called from binder_vma_close() when releasing address space.
 889  * Clears alloc->vma to prevent new incoming transactions from
 890  * allocating more buffers.
 891  */
 892 void binder_alloc_vma_close(struct binder_alloc *alloc)
 893 {
 894         binder_alloc_set_vma(alloc, NULL);
 895 }
 896
 897 /**
 898  * binder_alloc_free_page() - shrinker callback to free pages
 899  * @item:   item to free
 900  * @lock:   lock protecting the item
 901  * @cb_arg: callback argument
 902  *
 903  * Called from list_lru_walk() in binder_shrink_scan() to free
 904  * up pages when the system is under memory pressure.
 905  */
 906 enum lru_status binder_alloc_free_page(struct list_head *item,
 907                                        struct list_lru_one *lru,
 908                                        spinlock_t *lock,
 909                                        void *cb_arg)
 910         __must_hold(lock)
 911 {
 912         struct mm_struct *mm = NULL;
 913         struct binder_lru_page *page = container_of(item,
 914                                                     struct binder_lru_page,
 915                                                     lru);
 916         struct binder_alloc *alloc;
 917         uintptr_t page_addr;
 918         size_t index;
 919         struct vm_area_struct *vma;
 920
 921         alloc = page->alloc;
 922         if (!mutex_trylock(&alloc->mutex))
 923                 goto err_get_alloc_mutex_failed;
 924
 925         if (!page->page_ptr)
 926                 goto err_page_already_freed;
 927
 928         index = page - alloc->pages;
 929         page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
 930
 931         mm = alloc->vma_vm_mm;
 932         if (!mmget_not_zero(mm))
 933                 goto err_mmget;
 934         if (!down_write_trylock(&mm->mmap_sem))
 935                 goto err_down_write_mmap_sem_failed;
 936         vma = binder_alloc_get_vma(alloc);
 937
 938         list_lru_isolate(lru, item);
 939         spin_unlock(lock);
 940
 941         if (vma) {
 942                 trace_binder_unmap_user_start(alloc, index);
 943
 944                 zap_page_range(vma, page_addr, PAGE_SIZE);
 945
 946                 trace_binder_unmap_user_end(alloc, index);
 947         }
 948         up_write(&mm->mmap_sem);
 949         mmput(mm);
 950
 951         trace_binder_unmap_kernel_start(alloc, index);
 952
 953         __free_page(page->page_ptr);
 954         page->page_ptr = NULL;
 955
 956         trace_binder_unmap_kernel_end(alloc, index);
 957
 958         spin_lock(lock);
 959         mutex_unlock(&alloc->mutex);
 960         return LRU_REMOVED_RETRY;
 961
 962 err_down_write_mmap_sem_failed:
 963         mmput_async(mm);
 964 err_mmget:
 965 err_page_already_freed:
 966         mutex_unlock(&alloc->mutex);
 967 err_get_alloc_mutex_failed:
 968         return LRU_SKIP;
 969 }
 970
 971 static unsigned long
 972 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 973 {
 974         unsigned long ret = list_lru_count(&binder_alloc_lru);
 975         return ret;
 976 }
 977
 978 static unsigned long
 979 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 980 {
 981         unsigned long ret;
 982
 983         ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
 984                             NULL, sc->nr_to_scan);
 985         return ret;
 986 }
 987
 988 static struct shrinker binder_shrinker = {
 989         .count_objects = binder_shrink_count,
 990         .scan_objects = binder_shrink_scan,
 991         .seeks = DEFAULT_SEEKS,
 992 };
 993
 994 /**
 995  * binder_alloc_init() - called by binder_open() for per-proc initialization
 996  * @alloc: binder_alloc for this proc
 997  *
 998  * Called from binder_open() to initialize binder_alloc fields for
 999  * new binder proc
1000  */
1001 void binder_alloc_init(struct binder_alloc *alloc)
1002 {
1003         alloc->pid = current->group_leader->pid;
1004         mutex_init(&alloc->mutex);
1005         INIT_LIST_HEAD(&alloc->buffers);
1006 }
1007
1008 int binder_alloc_shrinker_init(void)
1009 {
1010         int ret = list_lru_init(&binder_alloc_lru);
1011
1012         if (ret == 0) {
1013                 ret = register_shrinker(&binder_shrinker);
1014                 if (ret)
1015                         list_lru_destroy(&binder_alloc_lru);
1016         }
1017         return ret;
1018 }
1019
1020 /**
1021  * check_buffer() - verify that buffer/offset is safe to access
1022  * @alloc: binder_alloc for this proc
1023  * @buffer: binder buffer to be accessed
1024  * @offset: offset into @buffer data
1025  * @bytes: bytes to access from offset
1026  *
1027  * Check that the @offset/@bytes are within the size of the given
1028  * @buffer and that the buffer is currently active and not freeable.
1029  * Offsets must also be multiples of sizeof(u32). The kernel is
1030  * allowed to touch the buffer in two cases:
1031  *
1032  * 1) when the buffer is being created:
1033  *     (buffer->free == 0 && buffer->allow_user_free == 0)
1034  * 2) when the buffer is being torn down:
1035  *     (buffer->free == 0 && buffer->transaction == NULL).
1036  *
1037  * Return: true if the buffer is safe to access
1038  */
1039 static inline bool check_buffer(struct binder_alloc *alloc,
1040                                 struct binder_buffer *buffer,
1041                                 binder_size_t offset, size_t bytes)
1042 {
1043         size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1044
1045         return buffer_size >= bytes &&
1046                 offset <= buffer_size - bytes &&
1047                 IS_ALIGNED(offset, sizeof(u32)) &&
1048                 !buffer->free &&
1049                 (!buffer->allow_user_free || !buffer->transaction);
1050 }
1051
1052 /**
1053  * binder_alloc_get_page() - get kernel pointer for given buffer offset
1054  * @alloc: binder_alloc for this proc
1055  * @buffer: binder buffer to be accessed
1056  * @buffer_offset: offset into @buffer data
1057  * @pgoffp: address to copy final page offset to
1058  *
1059  * Lookup the struct page corresponding to the address
1060  * at @buffer_offset into @buffer->user_data. If @pgoffp is not
1061  * NULL, the byte-offset into the page is written there.
1062  *
1063  * The caller is responsible to ensure that the offset points
1064  * to a valid address within the @buffer and that @buffer is
1065  * not freeable by the user. Since it can't be freed, we are
1066  * guaranteed that the corresponding elements of @alloc->pages[]
1067  * cannot change.
1068  *
1069  * Return: struct page
1070  */
1071 static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1072                                           struct binder_buffer *buffer,
1073                                           binder_size_t buffer_offset,
1074                                           pgoff_t *pgoffp)
1075 {
1076         binder_size_t buffer_space_offset = buffer_offset +
1077                 (buffer->user_data - alloc->buffer);
1078         pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
1079         size_t index = buffer_space_offset >> PAGE_SHIFT;
1080         struct binder_lru_page *lru_page;
1081
1082         lru_page = &alloc->pages[index];
1083         *pgoffp = pgoff;
1084         return lru_page->page_ptr;
1085 }
1086
1087 /**
1088  * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1089  * @alloc: binder_alloc for this proc
1090  * @buffer: binder buffer to be accessed
1091  * @buffer_offset: offset into @buffer data
1092  * @from: userspace pointer to source buffer
1093  * @bytes: bytes to copy
1094  *
1095  * Copy bytes from source userspace to target buffer.
1096  *
1097  * Return: bytes remaining to be copied
1098  */
1099 unsigned long
1100 binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1101                                  struct binder_buffer *buffer,
1102                                  binder_size_t buffer_offset,
1103                                  const void __user *from,
1104                                  size_t bytes)
1105 {
1106         if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1107                 return bytes;
1108
1109         while (bytes) {
1110                 unsigned long size;
1111                 unsigned long ret;
1112                 struct page *page;
1113                 pgoff_t pgoff;
1114                 void *kptr;
1115
1116                 page = binder_alloc_get_page(alloc, buffer,
1117                                              buffer_offset, &pgoff);
1118                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1119                 kptr = kmap(page) + pgoff;
1120                 ret = copy_from_user(kptr, from, size);
1121                 kunmap(page);
1122                 if (ret)
1123                         return bytes - size + ret;
1124                 bytes -= size;
1125                 from += size;
1126                 buffer_offset += size;
1127         }
1128         return 0;
1129 }
1130
1131 static void binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1132                                         bool to_buffer,
1133                                         struct binder_buffer *buffer,
1134                                         binder_size_t buffer_offset,
1135                                         void *ptr,
1136                                         size_t bytes)
1137 {
1138         /* All copies must be 32-bit aligned and 32-bit size */
1139         BUG_ON(!check_buffer(alloc, buffer, buffer_offset, bytes));
1140
1141         while (bytes) {
1142                 unsigned long size;
1143                 struct page *page;
1144                 pgoff_t pgoff;
1145                 void *tmpptr;
1146                 void *base_ptr;
1147
1148                 page = binder_alloc_get_page(alloc, buffer,
1149                                              buffer_offset, &pgoff);
1150                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1151                 base_ptr = kmap_atomic(page);
1152                 tmpptr = base_ptr + pgoff;
1153                 if (to_buffer)
1154                         memcpy(tmpptr, ptr, size);
1155                 else
1156                         memcpy(ptr, tmpptr, size);
1157                 /*
1158                  * kunmap_atomic() takes care of flushing the cache
1159                  * if this device has VIVT cache arch
1160                  */
1161                 kunmap_atomic(base_ptr);
1162                 bytes -= size;
1163                 pgoff = 0;
1164                 ptr = ptr + size;
1165                 buffer_offset += size;
1166         }
1167 }
1168
1169 void binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1170                                  struct binder_buffer *buffer,
1171                                  binder_size_t buffer_offset,
1172                                  void *src,
1173                                  size_t bytes)
1174 {
1175         binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1176                                     src, bytes);
1177 }
1178
1179 void binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1180                                    void *dest,
1181                                    struct binder_buffer *buffer,
1182                                    binder_size_t buffer_offset,
1183                                    size_t bytes)
1184 {
1185         binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
1186                                     dest, bytes);
1187 }
1188