drivers/android/binder_alloc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* binder_alloc.c
   3  *
   4  * Android IPC Subsystem
   5  *
   6  * Copyright (C) 2007-2017 Google, Inc.
   7  */
   8
   9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11 #include <linux/list.h>
  12 #include <linux/sched/mm.h>
  13 #include <linux/module.h>
  14 #include <linux/rtmutex.h>
  15 #include <linux/rbtree.h>
  16 #include <linux/seq_file.h>
  17 #include <linux/vmalloc.h>
  18 #include <linux/slab.h>
  19 #include <linux/sched.h>
  20 #include <linux/list_lru.h>
  21 #include <linux/ratelimit.h>
  22 #include <asm/cacheflush.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/highmem.h>
  25 #include <linux/sizes.h>
  26 #include "binder_alloc.h"
  27 #include "binder_trace.h"
  28
  29 struct list_lru binder_alloc_lru;
  30
  31 static DEFINE_MUTEX(binder_alloc_mmap_lock);
  32
  33 enum {
  34         BINDER_DEBUG_USER_ERROR             = 1U << 0,
  35         BINDER_DEBUG_OPEN_CLOSE             = 1U << 1,
  36         BINDER_DEBUG_BUFFER_ALLOC           = 1U << 2,
  37         BINDER_DEBUG_BUFFER_ALLOC_ASYNC     = 1U << 3,
  38 };
  39 static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
  40
  41 module_param_named(debug_mask, binder_alloc_debug_mask,
  42                    uint, 0644);
  43
  44 #define binder_alloc_debug(mask, x...) \
  45         do { \
  46                 if (binder_alloc_debug_mask & mask) \
  47                         pr_info_ratelimited(x); \
  48         } while (0)
  49
  50 static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
  51 {
  52         return list_entry(buffer->entry.next, struct binder_buffer, entry);
  53 }
  54
  55 static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
  56 {
  57         return list_entry(buffer->entry.prev, struct binder_buffer, entry);
  58 }
  59
  60 static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
  61                                        struct binder_buffer *buffer)
  62 {
  63         if (list_is_last(&buffer->entry, &alloc->buffers))
  64                 return alloc->buffer + alloc->buffer_size - buffer->user_data;
  65         return binder_buffer_next(buffer)->user_data - buffer->user_data;
  66 }
  67
  68 static void binder_insert_free_buffer(struct binder_alloc *alloc,
  69                                       struct binder_buffer *new_buffer)
  70 {
  71         struct rb_node **p = &alloc->free_buffers.rb_node;
  72         struct rb_node *parent = NULL;
  73         struct binder_buffer *buffer;
  74         size_t buffer_size;
  75         size_t new_buffer_size;
  76
  77         BUG_ON(!new_buffer->free);
  78
  79         new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
  80
  81         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
  82                      "%d: add free buffer, size %zd, at %pK\n",
  83                       alloc->pid, new_buffer_size, new_buffer);
  84
  85         while (*p) {
  86                 parent = *p;
  87                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
  88                 BUG_ON(!buffer->free);
  89
  90                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
  91
  92                 if (new_buffer_size < buffer_size)
  93                         p = &parent->rb_left;
  94                 else
  95                         p = &parent->rb_right;
  96         }
  97         rb_link_node(&new_buffer->rb_node, parent, p);
  98         rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
  99 }
 100
 101 static void binder_insert_allocated_buffer_locked(
 102                 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
 103 {
 104         struct rb_node **p = &alloc->allocated_buffers.rb_node;
 105         struct rb_node *parent = NULL;
 106         struct binder_buffer *buffer;
 107
 108         BUG_ON(new_buffer->free);
 109
 110         while (*p) {
 111                 parent = *p;
 112                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
 113                 BUG_ON(buffer->free);
 114
 115                 if (new_buffer->user_data < buffer->user_data)
 116                         p = &parent->rb_left;
 117                 else if (new_buffer->user_data > buffer->user_data)
 118                         p = &parent->rb_right;
 119                 else
 120                         BUG();
 121         }
 122         rb_link_node(&new_buffer->rb_node, parent, p);
 123         rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
 124 }
 125
 126 static struct binder_buffer *binder_alloc_prepare_to_free_locked(
 127                 struct binder_alloc *alloc,
 128                 uintptr_t user_ptr)
 129 {
 130         struct rb_node *n = alloc->allocated_buffers.rb_node;
 131         struct binder_buffer *buffer;
 132         void __user *uptr;
 133
 134         uptr = (void __user *)user_ptr;
 135
 136         while (n) {
 137                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 138                 BUG_ON(buffer->free);
 139
 140                 if (uptr < buffer->user_data)
 141                         n = n->rb_left;
 142                 else if (uptr > buffer->user_data)
 143                         n = n->rb_right;
 144                 else {
 145                         /*
 146                          * Guard against user threads attempting to
 147                          * free the buffer when in use by kernel or
 148                          * after it's already been freed.
 149                          */
 150                         if (!buffer->allow_user_free)
 151                                 return ERR_PTR(-EPERM);
 152                         buffer->allow_user_free = 0;
 153                         return buffer;
 154                 }
 155         }
 156         return NULL;
 157 }
 158
 159 /**
 160  * binder_alloc_prepare_to_free() - get buffer given user ptr
 161  * @alloc:      binder_alloc for this proc
 162  * @user_ptr:   User pointer to buffer data
 163  *
 164  * Validate userspace pointer to buffer data and return buffer corresponding to
 165  * that user pointer. Search the rb tree for buffer that matches user data
 166  * pointer.
 167  *
 168  * Return:      Pointer to buffer or NULL
 169  */
 170 struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
 171                                                    uintptr_t user_ptr)
 172 {
 173         struct binder_buffer *buffer;
 174
 175         mutex_lock(&alloc->mutex);
 176         buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
 177         mutex_unlock(&alloc->mutex);
 178         return buffer;
 179 }
 180
 181 static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
 182                                     void __user *start, void __user *end)
 183 {
 184         void __user *page_addr;
 185         unsigned long user_page_addr;
 186         struct binder_lru_page *page;
 187         struct vm_area_struct *vma = NULL;
 188         struct mm_struct *mm = NULL;
 189         bool need_mm = false;
 190
 191         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 192                      "%d: %s pages %pK-%pK\n", alloc->pid,
 193                      allocate ? "allocate" : "free", start, end);
 194
 195         if (end <= start)
 196                 return 0;
 197
 198         trace_binder_update_page_range(alloc, allocate, start, end);
 199
 200         if (allocate == 0)
 201                 goto free_range;
 202
 203         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 204                 page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
 205                 if (!page->page_ptr) {
 206                         need_mm = true;
 207                         break;
 208                 }
 209         }
 210
 211         if (need_mm && mmget_not_zero(alloc->vma_vm_mm))
 212                 mm = alloc->vma_vm_mm;
 213
 214         if (mm) {
 215                 down_read(&mm->mmap_sem);
 216                 vma = alloc->vma;
 217         }
 218
 219         if (!vma && need_mm) {
 220                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 221                                    "%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
 222                                    alloc->pid);
 223                 goto err_no_vma;
 224         }
 225
 226         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 227                 int ret;
 228                 bool on_lru;
 229                 size_t index;
 230
 231                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 232                 page = &alloc->pages[index];
 233
 234                 if (page->page_ptr) {
 235                         trace_binder_alloc_lru_start(alloc, index);
 236
 237                         on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
 238                         WARN_ON(!on_lru);
 239
 240                         trace_binder_alloc_lru_end(alloc, index);
 241                         continue;
 242                 }
 243
 244                 if (WARN_ON(!vma))
 245                         goto err_page_ptr_cleared;
 246
 247                 trace_binder_alloc_page_start(alloc, index);
 248                 page->page_ptr = alloc_page(GFP_KERNEL |
 249                                             __GFP_HIGHMEM |
 250                                             __GFP_ZERO);
 251                 if (!page->page_ptr) {
 252                         pr_err("%d: binder_alloc_buf failed for page at %pK\n",
 253                                 alloc->pid, page_addr);
 254                         goto err_alloc_page_failed;
 255                 }
 256                 page->alloc = alloc;
 257                 INIT_LIST_HEAD(&page->lru);
 258
 259                 user_page_addr = (uintptr_t)page_addr;
 260                 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
 261                 if (ret) {
 262                         pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
 263                                alloc->pid, user_page_addr);
 264                         goto err_vm_insert_page_failed;
 265                 }
 266
 267                 if (index + 1 > alloc->pages_high)
 268                         alloc->pages_high = index + 1;
 269
 270                 trace_binder_alloc_page_end(alloc, index);
 271         }
 272         if (mm) {
 273                 up_read(&mm->mmap_sem);
 274                 mmput(mm);
 275         }
 276         return 0;
 277
 278 free_range:
 279         for (page_addr = end - PAGE_SIZE; page_addr >= start;
 280              page_addr -= PAGE_SIZE) {
 281                 bool ret;
 282                 size_t index;
 283
 284                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 285                 page = &alloc->pages[index];
 286
 287                 trace_binder_free_lru_start(alloc, index);
 288
 289                 ret = list_lru_add(&binder_alloc_lru, &page->lru);
 290                 WARN_ON(!ret);
 291
 292                 trace_binder_free_lru_end(alloc, index);
 293                 continue;
 294
 295 err_vm_insert_page_failed:
 296                 __free_page(page->page_ptr);
 297                 page->page_ptr = NULL;
 298 err_alloc_page_failed:
 299 err_page_ptr_cleared:
 300                 ;
 301         }
 302 err_no_vma:
 303         if (mm) {
 304                 up_read(&mm->mmap_sem);
 305                 mmput(mm);
 306         }
 307         return vma ? -ENOMEM : -ESRCH;
 308 }
 309
 310
 311 static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
 312                 struct vm_area_struct *vma)
 313 {
 314         if (vma)
 315                 alloc->vma_vm_mm = vma->vm_mm;
 316         /*
 317          * If we see alloc->vma is not NULL, buffer data structures set up
 318          * completely. Look at smp_rmb side binder_alloc_get_vma.
 319          * We also want to guarantee new alloc->vma_vm_mm is always visible
 320          * if alloc->vma is set.
 321          */
 322         smp_wmb();
 323         alloc->vma = vma;
 324 }
 325
 326 static inline struct vm_area_struct *binder_alloc_get_vma(
 327                 struct binder_alloc *alloc)
 328 {
 329         struct vm_area_struct *vma = NULL;
 330
 331         if (alloc->vma) {
 332                 /* Look at description in binder_alloc_set_vma */
 333                 smp_rmb();
 334                 vma = alloc->vma;
 335         }
 336         return vma;
 337 }
 338
 339 static struct binder_buffer *binder_alloc_new_buf_locked(
 340                                 struct binder_alloc *alloc,
 341                                 size_t data_size,
 342                                 size_t offsets_size,
 343                                 size_t extra_buffers_size,
 344                                 int is_async)
 345 {
 346         struct rb_node *n = alloc->free_buffers.rb_node;
 347         struct binder_buffer *buffer;
 348         size_t buffer_size;
 349         struct rb_node *best_fit = NULL;
 350         void __user *has_page_addr;
 351         void __user *end_page_addr;
 352         size_t size, data_offsets_size;
 353         int ret;
 354
 355         if (!binder_alloc_get_vma(alloc)) {
 356                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 357                                    "%d: binder_alloc_buf, no vma\n",
 358                                    alloc->pid);
 359                 return ERR_PTR(-ESRCH);
 360         }
 361
 362         data_offsets_size = ALIGN(data_size, sizeof(void *)) +
 363                 ALIGN(offsets_size, sizeof(void *));
 364
 365         if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
 366                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 367                                 "%d: got transaction with invalid size %zd-%zd\n",
 368                                 alloc->pid, data_size, offsets_size);
 369                 return ERR_PTR(-EINVAL);
 370         }
 371         size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
 372         if (size < data_offsets_size || size < extra_buffers_size) {
 373                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 374                                 "%d: got transaction with invalid extra_buffers_size %zd\n",
 375                                 alloc->pid, extra_buffers_size);
 376                 return ERR_PTR(-EINVAL);
 377         }
 378         if (is_async &&
 379             alloc->free_async_space < size + sizeof(struct binder_buffer)) {
 380                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 381                              "%d: binder_alloc_buf size %zd failed, no async space left\n",
 382                               alloc->pid, size);
 383                 return ERR_PTR(-ENOSPC);
 384         }
 385
 386         /* Pad 0-size buffers so they get assigned unique addresses */
 387         size = max(size, sizeof(void *));
 388
 389         while (n) {
 390                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 391                 BUG_ON(!buffer->free);
 392                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 393
 394                 if (size < buffer_size) {
 395                         best_fit = n;
 396                         n = n->rb_left;
 397                 } else if (size > buffer_size)
 398                         n = n->rb_right;
 399                 else {
 400                         best_fit = n;
 401                         break;
 402                 }
 403         }
 404         if (best_fit == NULL) {
 405                 size_t allocated_buffers = 0;
 406                 size_t largest_alloc_size = 0;
 407                 size_t total_alloc_size = 0;
 408                 size_t free_buffers = 0;
 409                 size_t largest_free_size = 0;
 410                 size_t total_free_size = 0;
 411
 412                 for (n = rb_first(&alloc->allocated_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                         allocated_buffers++;
 417                         total_alloc_size += buffer_size;
 418                         if (buffer_size > largest_alloc_size)
 419                                 largest_alloc_size = buffer_size;
 420                 }
 421                 for (n = rb_first(&alloc->free_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                         free_buffers++;
 426                         total_free_size += buffer_size;
 427                         if (buffer_size > largest_free_size)
 428                                 largest_free_size = buffer_size;
 429                 }
 430                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 431                                    "%d: binder_alloc_buf size %zd failed, no address space\n",
 432                                    alloc->pid, size);
 433                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 434                                    "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
 435                                    total_alloc_size, allocated_buffers,
 436                                    largest_alloc_size, total_free_size,
 437                                    free_buffers, largest_free_size);
 438                 return ERR_PTR(-ENOSPC);
 439         }
 440         if (n == NULL) {
 441                 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
 442                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 443         }
 444
 445         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 446                      "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
 447                       alloc->pid, size, buffer, buffer_size);
 448
 449         has_page_addr = (void __user *)
 450                 (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
 451         WARN_ON(n && buffer_size != size);
 452         end_page_addr =
 453                 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
 454         if (end_page_addr > has_page_addr)
 455                 end_page_addr = has_page_addr;
 456         ret = binder_update_page_range(alloc, 1, (void __user *)
 457                 PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
 458         if (ret)
 459                 return ERR_PTR(ret);
 460
 461         if (buffer_size != size) {
 462                 struct binder_buffer *new_buffer;
 463
 464                 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 465                 if (!new_buffer) {
 466                         pr_err("%s: %d failed to alloc new buffer struct\n",
 467                                __func__, alloc->pid);
 468                         goto err_alloc_buf_struct_failed;
 469                 }
 470                 new_buffer->user_data = (u8 __user *)buffer->user_data + size;
 471                 list_add(&new_buffer->entry, &buffer->entry);
 472                 new_buffer->free = 1;
 473                 binder_insert_free_buffer(alloc, new_buffer);
 474         }
 475
 476         rb_erase(best_fit, &alloc->free_buffers);
 477         buffer->free = 0;
 478         buffer->allow_user_free = 0;
 479         binder_insert_allocated_buffer_locked(alloc, buffer);
 480         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 481                      "%d: binder_alloc_buf size %zd got %pK\n",
 482                       alloc->pid, size, buffer);
 483         buffer->data_size = data_size;
 484         buffer->offsets_size = offsets_size;
 485         buffer->async_transaction = is_async;
 486         buffer->extra_buffers_size = extra_buffers_size;
 487         if (is_async) {
 488                 alloc->free_async_space -= size + sizeof(struct binder_buffer);
 489                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 490                              "%d: binder_alloc_buf size %zd async free %zd\n",
 491                               alloc->pid, size, alloc->free_async_space);
 492         }
 493         return buffer;
 494
 495 err_alloc_buf_struct_failed:
 496         binder_update_page_range(alloc, 0, (void __user *)
 497                                  PAGE_ALIGN((uintptr_t)buffer->user_data),
 498                                  end_page_addr);
 499         return ERR_PTR(-ENOMEM);
 500 }
 501
 502 /**
 503  * binder_alloc_new_buf() - Allocate a new binder buffer
 504  * @alloc:              binder_alloc for this proc
 505  * @data_size:          size of user data buffer
 506  * @offsets_size:       user specified buffer offset
 507  * @extra_buffers_size: size of extra space for meta-data (eg, security context)
 508  * @is_async:           buffer for async transaction
 509  *
 510  * Allocate a new buffer given the requested sizes. Returns
 511  * the kernel version of the buffer pointer. The size allocated
 512  * is the sum of the three given sizes (each rounded up to
 513  * pointer-sized boundary)
 514  *
 515  * Return:      The allocated buffer or %NULL if error
 516  */
 517 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 518                                            size_t data_size,
 519                                            size_t offsets_size,
 520                                            size_t extra_buffers_size,
 521                                            int is_async)
 522 {
 523         struct binder_buffer *buffer;
 524
 525         mutex_lock(&alloc->mutex);
 526         buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
 527                                              extra_buffers_size, is_async);
 528         mutex_unlock(&alloc->mutex);
 529         return buffer;
 530 }
 531
 532 static void __user *buffer_start_page(struct binder_buffer *buffer)
 533 {
 534         return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
 535 }
 536
 537 static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
 538 {
 539         return (void __user *)
 540                 (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
 541 }
 542
 543 static void binder_delete_free_buffer(struct binder_alloc *alloc,
 544                                       struct binder_buffer *buffer)
 545 {
 546         struct binder_buffer *prev, *next = NULL;
 547         bool to_free = true;
 548         BUG_ON(alloc->buffers.next == &buffer->entry);
 549         prev = binder_buffer_prev(buffer);
 550         BUG_ON(!prev->free);
 551         if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
 552                 to_free = false;
 553                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 554                                    "%d: merge free, buffer %pK share page with %pK\n",
 555                                    alloc->pid, buffer->user_data,
 556                                    prev->user_data);
 557         }
 558
 559         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 560                 next = binder_buffer_next(buffer);
 561                 if (buffer_start_page(next) == 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,
 566                                            buffer->user_data,
 567                                            next->user_data);
 568                 }
 569         }
 570
 571         if (PAGE_ALIGNED(buffer->user_data)) {
 572                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 573                                    "%d: merge free, buffer start %pK is page aligned\n",
 574                                    alloc->pid, buffer->user_data);
 575                 to_free = false;
 576         }
 577
 578         if (to_free) {
 579                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 580                                    "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
 581                                    alloc->pid, buffer->user_data,
 582                                    prev->user_data,
 583                                    next ? next->user_data : NULL);
 584                 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
 585                                          buffer_start_page(buffer) + PAGE_SIZE);
 586         }
 587         list_del(&buffer->entry);
 588         kfree(buffer);
 589 }
 590
 591 static void binder_free_buf_locked(struct binder_alloc *alloc,
 592                                    struct binder_buffer *buffer)
 593 {
 594         size_t size, buffer_size;
 595
 596         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 597
 598         size = ALIGN(buffer->data_size, sizeof(void *)) +
 599                 ALIGN(buffer->offsets_size, sizeof(void *)) +
 600                 ALIGN(buffer->extra_buffers_size, sizeof(void *));
 601
 602         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 603                      "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
 604                       alloc->pid, buffer, size, buffer_size);
 605
 606         BUG_ON(buffer->free);
 607         BUG_ON(size > buffer_size);
 608         BUG_ON(buffer->transaction != NULL);
 609         BUG_ON(buffer->user_data < alloc->buffer);
 610         BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
 611
 612         if (buffer->async_transaction) {
 613                 alloc->free_async_space += size + sizeof(struct binder_buffer);
 614
 615                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 616                              "%d: binder_free_buf size %zd async free %zd\n",
 617                               alloc->pid, size, alloc->free_async_space);
 618         }
 619
 620         binder_update_page_range(alloc, 0,
 621                 (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
 622                 (void __user *)(((uintptr_t)
 623                           buffer->user_data + buffer_size) & PAGE_MASK));
 624
 625         rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
 626         buffer->free = 1;
 627         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 628                 struct binder_buffer *next = binder_buffer_next(buffer);
 629
 630                 if (next->free) {
 631                         rb_erase(&next->rb_node, &alloc->free_buffers);
 632                         binder_delete_free_buffer(alloc, next);
 633                 }
 634         }
 635         if (alloc->buffers.next != &buffer->entry) {
 636                 struct binder_buffer *prev = binder_buffer_prev(buffer);
 637
 638                 if (prev->free) {
 639                         binder_delete_free_buffer(alloc, buffer);
 640                         rb_erase(&prev->rb_node, &alloc->free_buffers);
 641                         buffer = prev;
 642                 }
 643         }
 644         binder_insert_free_buffer(alloc, buffer);
 645 }
 646
 647 /**
 648  * binder_alloc_free_buf() - free a binder buffer
 649  * @alloc:      binder_alloc for this proc
 650  * @buffer:     kernel pointer to buffer
 651  *
 652  * Free the buffer allocated via binder_alloc_new_buffer()
 653  */
 654 void binder_alloc_free_buf(struct binder_alloc *alloc,
 655                             struct binder_buffer *buffer)
 656 {
 657         mutex_lock(&alloc->mutex);
 658         binder_free_buf_locked(alloc, buffer);
 659         mutex_unlock(&alloc->mutex);
 660 }
 661
 662 /**
 663  * binder_alloc_mmap_handler() - map virtual address space for proc
 664  * @alloc:      alloc structure for this proc
 665  * @vma:        vma passed to mmap()
 666  *
 667  * Called by binder_mmap() to initialize the space specified in
 668  * vma for allocating binder buffers
 669  *
 670  * Return:
 671  *      0 = success
 672  *      -EBUSY = address space already mapped
 673  *      -ENOMEM = failed to map memory to given address space
 674  */
 675 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 676                               struct vm_area_struct *vma)
 677 {
 678         int ret;
 679         const char *failure_string;
 680         struct binder_buffer *buffer;
 681
 682         mutex_lock(&binder_alloc_mmap_lock);
 683         if (alloc->buffer_size) {
 684                 ret = -EBUSY;
 685                 failure_string = "already mapped";
 686                 goto err_already_mapped;
 687         }
 688         alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
 689                                    SZ_4M);
 690         mutex_unlock(&binder_alloc_mmap_lock);
 691
 692         alloc->buffer = (void __user *)vma->vm_start;
 693
 694         alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
 695                                sizeof(alloc->pages[0]),
 696                                GFP_KERNEL);
 697         if (alloc->pages == NULL) {
 698                 ret = -ENOMEM;
 699                 failure_string = "alloc page array";
 700                 goto err_alloc_pages_failed;
 701         }
 702
 703         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 704         if (!buffer) {
 705                 ret = -ENOMEM;
 706                 failure_string = "alloc buffer struct";
 707                 goto err_alloc_buf_struct_failed;
 708         }
 709
 710         buffer->user_data = alloc->buffer;
 711         list_add(&buffer->entry, &alloc->buffers);
 712         buffer->free = 1;
 713         binder_insert_free_buffer(alloc, buffer);
 714         alloc->free_async_space = alloc->buffer_size / 2;
 715         binder_alloc_set_vma(alloc, vma);
 716         mmgrab(alloc->vma_vm_mm);
 717
 718         return 0;
 719
 720 err_alloc_buf_struct_failed:
 721         kfree(alloc->pages);
 722         alloc->pages = NULL;
 723 err_alloc_pages_failed:
 724         alloc->buffer = NULL;
 725         mutex_lock(&binder_alloc_mmap_lock);
 726         alloc->buffer_size = 0;
 727 err_already_mapped:
 728         mutex_unlock(&binder_alloc_mmap_lock);
 729         binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 730                            "%s: %d %lx-%lx %s failed %d\n", __func__,
 731                            alloc->pid, vma->vm_start, vma->vm_end,
 732                            failure_string, ret);
 733         return ret;
 734 }
 735
 736
 737 void binder_alloc_deferred_release(struct binder_alloc *alloc)
 738 {
 739         struct rb_node *n;
 740         int buffers, page_count;
 741         struct binder_buffer *buffer;
 742
 743         buffers = 0;
 744         mutex_lock(&alloc->mutex);
 745         BUG_ON(alloc->vma);
 746
 747         while ((n = rb_first(&alloc->allocated_buffers))) {
 748                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 749
 750                 /* Transaction should already have been freed */
 751                 BUG_ON(buffer->transaction);
 752
 753                 binder_free_buf_locked(alloc, buffer);
 754                 buffers++;
 755         }
 756
 757         while (!list_empty(&alloc->buffers)) {
 758                 buffer = list_first_entry(&alloc->buffers,
 759                                           struct binder_buffer, entry);
 760                 WARN_ON(!buffer->free);
 761
 762                 list_del(&buffer->entry);
 763                 WARN_ON_ONCE(!list_empty(&alloc->buffers));
 764                 kfree(buffer);
 765         }
 766
 767         page_count = 0;
 768         if (alloc->pages) {
 769                 int i;
 770
 771                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 772                         void __user *page_addr;
 773                         bool on_lru;
 774
 775                         if (!alloc->pages[i].page_ptr)
 776                                 continue;
 777
 778                         on_lru = list_lru_del(&binder_alloc_lru,
 779                                               &alloc->pages[i].lru);
 780                         page_addr = alloc->buffer + i * PAGE_SIZE;
 781                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 782                                      "%s: %d: page %d at %pK %s\n",
 783                                      __func__, alloc->pid, i, page_addr,
 784                                      on_lru ? "on lru" : "active");
 785                         __free_page(alloc->pages[i].page_ptr);
 786                         page_count++;
 787                 }
 788                 kfree(alloc->pages);
 789         }
 790         mutex_unlock(&alloc->mutex);
 791         if (alloc->vma_vm_mm)
 792                 mmdrop(alloc->vma_vm_mm);
 793
 794         binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
 795                      "%s: %d buffers %d, pages %d\n",
 796                      __func__, alloc->pid, buffers, page_count);
 797 }
 798
 799 static void print_binder_buffer(struct seq_file *m, const char *prefix,
 800                                 struct binder_buffer *buffer)
 801 {
 802         seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
 803                    prefix, buffer->debug_id, buffer->user_data,
 804                    buffer->data_size, buffer->offsets_size,
 805                    buffer->extra_buffers_size,
 806                    buffer->transaction ? "active" : "delivered");
 807 }
 808
 809 /**
 810  * binder_alloc_print_allocated() - print buffer info
 811  * @m:     seq_file for output via seq_printf()
 812  * @alloc: binder_alloc for this proc
 813  *
 814  * Prints information about every buffer associated with
 815  * the binder_alloc state to the given seq_file
 816  */
 817 void binder_alloc_print_allocated(struct seq_file *m,
 818                                   struct binder_alloc *alloc)
 819 {
 820         struct rb_node *n;
 821
 822         mutex_lock(&alloc->mutex);
 823         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 824                 print_binder_buffer(m, "  buffer",
 825                                     rb_entry(n, struct binder_buffer, rb_node));
 826         mutex_unlock(&alloc->mutex);
 827 }
 828
 829 /**
 830  * binder_alloc_print_pages() - print page usage
 831  * @m:     seq_file for output via seq_printf()
 832  * @alloc: binder_alloc for this proc
 833  */
 834 void binder_alloc_print_pages(struct seq_file *m,
 835                               struct binder_alloc *alloc)
 836 {
 837         struct binder_lru_page *page;
 838         int i;
 839         int active = 0;
 840         int lru = 0;
 841         int free = 0;
 842
 843         mutex_lock(&alloc->mutex);
 844         /*
 845          * Make sure the binder_alloc is fully initialized, otherwise we might
 846          * read inconsistent state.
 847          */
 848         if (binder_alloc_get_vma(alloc) != NULL) {
 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         }
 859         mutex_unlock(&alloc->mutex);
 860         seq_printf(m, "  pages: %d:%d:%d\n", active, lru, free);
 861         seq_printf(m, "  pages high watermark: %zu\n", alloc->pages_high);
 862 }
 863
 864 /**
 865  * binder_alloc_get_allocated_count() - return count of buffers
 866  * @alloc: binder_alloc for this proc
 867  *
 868  * Return: count of allocated buffers
 869  */
 870 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
 871 {
 872         struct rb_node *n;
 873         int count = 0;
 874
 875         mutex_lock(&alloc->mutex);
 876         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 877                 count++;
 878         mutex_unlock(&alloc->mutex);
 879         return count;
 880 }
 881
 882
 883 /**
 884  * binder_alloc_vma_close() - invalidate address space
 885  * @alloc: binder_alloc for this proc
 886  *
 887  * Called from binder_vma_close() when releasing address space.
 888  * Clears alloc->vma to prevent new incoming transactions from
 889  * allocating more buffers.
 890  */
 891 void binder_alloc_vma_close(struct binder_alloc *alloc)
 892 {
 893         binder_alloc_set_vma(alloc, NULL);
 894 }
 895
 896 /**
 897  * binder_alloc_free_page() - shrinker callback to free pages
 898  * @item:   item to free
 899  * @lock:   lock protecting the item
 900  * @cb_arg: callback argument
 901  *
 902  * Called from list_lru_walk() in binder_shrink_scan() to free
 903  * up pages when the system is under memory pressure.
 904  */
 905 enum lru_status binder_alloc_free_page(struct list_head *item,
 906                                        struct list_lru_one *lru,
 907                                        spinlock_t *lock,
 908                                        void *cb_arg)
 909         __must_hold(lock)
 910 {
 911         struct mm_struct *mm = NULL;
 912         struct binder_lru_page *page = container_of(item,
 913                                                     struct binder_lru_page,
 914                                                     lru);
 915         struct binder_alloc *alloc;
 916         uintptr_t page_addr;
 917         size_t index;
 918         struct vm_area_struct *vma;
 919
 920         alloc = page->alloc;
 921         if (!mutex_trylock(&alloc->mutex))
 922                 goto err_get_alloc_mutex_failed;
 923
 924         if (!page->page_ptr)
 925                 goto err_page_already_freed;
 926
 927         index = page - alloc->pages;
 928         page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
 929
 930         mm = alloc->vma_vm_mm;
 931         if (!mmget_not_zero(mm))
 932                 goto err_mmget;
 933         if (!down_read_trylock(&mm->mmap_sem))
 934                 goto err_down_read_mmap_sem_failed;
 935         vma = binder_alloc_get_vma(alloc);
 936
 937         list_lru_isolate(lru, item);
 938         spin_unlock(lock);
 939
 940         if (vma) {
 941                 trace_binder_unmap_user_start(alloc, index);
 942
 943                 zap_page_range(vma, page_addr, PAGE_SIZE);
 944
 945                 trace_binder_unmap_user_end(alloc, index);
 946         }
 947         up_read(&mm->mmap_sem);
 948         mmput(mm);
 949
 950         trace_binder_unmap_kernel_start(alloc, index);
 951
 952         __free_page(page->page_ptr);
 953         page->page_ptr = NULL;
 954
 955         trace_binder_unmap_kernel_end(alloc, index);
 956
 957         spin_lock(lock);
 958         mutex_unlock(&alloc->mutex);
 959         return LRU_REMOVED_RETRY;
 960
 961 err_down_read_mmap_sem_failed:
 962         mmput_async(mm);
 963 err_mmget:
 964 err_page_already_freed:
 965         mutex_unlock(&alloc->mutex);
 966 err_get_alloc_mutex_failed:
 967         return LRU_SKIP;
 968 }
 969
 970 static unsigned long
 971 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 972 {
 973         unsigned long ret = list_lru_count(&binder_alloc_lru);
 974         return ret;
 975 }
 976
 977 static unsigned long
 978 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 979 {
 980         unsigned long ret;
 981
 982         ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
 983                             NULL, sc->nr_to_scan);
 984         return ret;
 985 }
 986
 987 static struct shrinker binder_shrinker = {
 988         .count_objects = binder_shrink_count,
 989         .scan_objects = binder_shrink_scan,
 990         .seeks = DEFAULT_SEEKS,
 991 };
 992
 993 /**
 994  * binder_alloc_init() - called by binder_open() for per-proc initialization
 995  * @alloc: binder_alloc for this proc
 996  *
 997  * Called from binder_open() to initialize binder_alloc fields for
 998  * new binder proc
 999  */
1000 void binder_alloc_init(struct binder_alloc *alloc)
1001 {
1002         alloc->pid = current->group_leader->pid;
1003         mutex_init(&alloc->mutex);
1004         INIT_LIST_HEAD(&alloc->buffers);
1005 }
1006
1007 int binder_alloc_shrinker_init(void)
1008 {
1009         int ret = list_lru_init(&binder_alloc_lru);
1010
1011         if (ret == 0) {
1012                 ret = register_shrinker(&binder_shrinker);
1013                 if (ret)
1014                         list_lru_destroy(&binder_alloc_lru);
1015         }
1016         return ret;
1017 }
1018
1019 /**
1020  * check_buffer() - verify that buffer/offset is safe to access
1021  * @alloc: binder_alloc for this proc
1022  * @buffer: binder buffer to be accessed
1023  * @offset: offset into @buffer data
1024  * @bytes: bytes to access from offset
1025  *
1026  * Check that the @offset/@bytes are within the size of the given
1027  * @buffer and that the buffer is currently active and not freeable.
1028  * Offsets must also be multiples of sizeof(u32). The kernel is
1029  * allowed to touch the buffer in two cases:
1030  *
1031  * 1) when the buffer is being created:
1032  *     (buffer->free == 0 && buffer->allow_user_free == 0)
1033  * 2) when the buffer is being torn down:
1034  *     (buffer->free == 0 && buffer->transaction == NULL).
1035  *
1036  * Return: true if the buffer is safe to access
1037  */
1038 static inline bool check_buffer(struct binder_alloc *alloc,
1039                                 struct binder_buffer *buffer,
1040                                 binder_size_t offset, size_t bytes)
1041 {
1042         size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1043
1044         return buffer_size >= bytes &&
1045                 offset <= buffer_size - bytes &&
1046                 IS_ALIGNED(offset, sizeof(u32)) &&
1047                 !buffer->free &&
1048                 (!buffer->allow_user_free || !buffer->transaction);
1049 }
1050
1051 /**
1052  * binder_alloc_get_page() - get kernel pointer for given buffer offset
1053  * @alloc: binder_alloc for this proc
1054  * @buffer: binder buffer to be accessed
1055  * @buffer_offset: offset into @buffer data
1056  * @pgoffp: address to copy final page offset to
1057  *
1058  * Lookup the struct page corresponding to the address
1059  * at @buffer_offset into @buffer->user_data. If @pgoffp is not
1060  * NULL, the byte-offset into the page is written there.
1061  *
1062  * The caller is responsible to ensure that the offset points
1063  * to a valid address within the @buffer and that @buffer is
1064  * not freeable by the user. Since it can't be freed, we are
1065  * guaranteed that the corresponding elements of @alloc->pages[]
1066  * cannot change.
1067  *
1068  * Return: struct page
1069  */
1070 static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
1071                                           struct binder_buffer *buffer,
1072                                           binder_size_t buffer_offset,
1073                                           pgoff_t *pgoffp)
1074 {
1075         binder_size_t buffer_space_offset = buffer_offset +
1076                 (buffer->user_data - alloc->buffer);
1077         pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
1078         size_t index = buffer_space_offset >> PAGE_SHIFT;
1079         struct binder_lru_page *lru_page;
1080
1081         lru_page = &alloc->pages[index];
1082         *pgoffp = pgoff;
1083         return lru_page->page_ptr;
1084 }
1085
1086 /**
1087  * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1088  * @alloc: binder_alloc for this proc
1089  * @buffer: binder buffer to be accessed
1090  * @buffer_offset: offset into @buffer data
1091  * @from: userspace pointer to source buffer
1092  * @bytes: bytes to copy
1093  *
1094  * Copy bytes from source userspace to target buffer.
1095  *
1096  * Return: bytes remaining to be copied
1097  */
1098 unsigned long
1099 binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1100                                  struct binder_buffer *buffer,
1101                                  binder_size_t buffer_offset,
1102                                  const void __user *from,
1103                                  size_t bytes)
1104 {
1105         if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1106                 return bytes;
1107
1108         while (bytes) {
1109                 unsigned long size;
1110                 unsigned long ret;
1111                 struct page *page;
1112                 pgoff_t pgoff;
1113                 void *kptr;
1114
1115                 page = binder_alloc_get_page(alloc, buffer,
1116                                              buffer_offset, &pgoff);
1117                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1118                 kptr = kmap(page) + pgoff;
1119                 ret = copy_from_user(kptr, from, size);
1120                 kunmap(page);
1121                 if (ret)
1122                         return bytes - size + ret;
1123                 bytes -= size;
1124                 from += size;
1125                 buffer_offset += size;
1126         }
1127         return 0;
1128 }
1129
1130 static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1131                                        bool to_buffer,
1132                                        struct binder_buffer *buffer,
1133                                        binder_size_t buffer_offset,
1134                                        void *ptr,
1135                                        size_t bytes)
1136 {
1137         /* All copies must be 32-bit aligned and 32-bit size */
1138         if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1139                 return -EINVAL;
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         return 0;
1168 }
1169
1170 int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1171                                 struct binder_buffer *buffer,
1172                                 binder_size_t buffer_offset,
1173                                 void *src,
1174                                 size_t bytes)
1175 {
1176         return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1177                                            src, bytes);
1178 }
1179
1180 int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1181                                   void *dest,
1182                                   struct binder_buffer *buffer,
1183                                   binder_size_t buffer_offset,
1184                                   size_t bytes)
1185 {
1186         return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
1187                                            dest, bytes);
1188 }
1189