drivers/android/binder_alloc.h

   1 /*
   2  * Copyright (C) 2017 Google, Inc.
   3  *
   4  * This software is licensed under the terms of the GNU General Public
   5  * License version 2, as published by the Free Software Foundation, and
   6  * may be copied, distributed, and modified under those terms.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #ifndef _LINUX_BINDER_ALLOC_H
  16 #define _LINUX_BINDER_ALLOC_H
  17
  18 #include <linux/rbtree.h>
  19 #include <linux/list.h>
  20 #include <linux/mm.h>
  21 #include <linux/rtmutex.h>
  22 #include <linux/vmalloc.h>
  23 #include <linux/slab.h>
  24 #include <linux/list_lru.h>
  25
  26 extern struct list_lru binder_alloc_lru;
  27 struct binder_transaction;
  28
  29 /**
  30  * struct binder_buffer - buffer used for binder transactions
  31  * @entry:              entry alloc->buffers
  32  * @rb_node:            node for allocated_buffers/free_buffers rb trees
  33  * @free:               true if buffer is free
  34  * @allow_user_free:    describe the second member of struct blah,
  35  * @async_transaction:  describe the second member of struct blah,
  36  * @debug_id:           describe the second member of struct blah,
  37  * @transaction:        describe the second member of struct blah,
  38  * @target_node:        describe the second member of struct blah,
  39  * @data_size:          describe the second member of struct blah,
  40  * @offsets_size:       describe the second member of struct blah,
  41  * @extra_buffers_size: describe the second member of struct blah,
  42  * @data:i              describe the second member of struct blah,
  43  *
  44  * Bookkeeping structure for binder transaction buffers
  45  */
  46 struct binder_buffer {
  47         struct list_head entry; /* free and allocated entries by address */
  48         struct rb_node rb_node; /* free entry by size or allocated entry */
  49                                 /* by address */
  50         unsigned free:1;
  51         unsigned allow_user_free:1;
  52         unsigned async_transaction:1;
  53         unsigned free_in_progress:1;
  54         unsigned debug_id:28;
  55
  56         struct binder_transaction *transaction;
  57
  58         struct binder_node *target_node;
  59         size_t data_size;
  60         size_t offsets_size;
  61         size_t extra_buffers_size;
  62         void *data;
  63 };
  64
  65 /**
  66  * struct binder_lru_page - page object used for binder shrinker
  67  * @page_ptr: pointer to physical page in mmap'd space
  68  * @lru:      entry in binder_alloc_lru
  69  * @alloc:    binder_alloc for a proc
  70  */
  71 struct binder_lru_page {
  72         struct list_head lru;
  73         struct page *page_ptr;
  74         struct binder_alloc *alloc;
  75 };
  76
  77 /**
  78  * struct binder_alloc - per-binder proc state for binder allocator
  79  * @vma:                vm_area_struct passed to mmap_handler
  80  *                      (invarient after mmap)
  81  * @tsk:                tid for task that called init for this proc
  82  *                      (invariant after init)
  83  * @vma_vm_mm:          copy of vma->vm_mm (invarient after mmap)
  84  * @buffer:             base of per-proc address space mapped via mmap
  85  * @user_buffer_offset: offset between user and kernel VAs for buffer
  86  * @buffers:            list of all buffers for this proc
  87  * @free_buffers:       rb tree of buffers available for allocation
  88  *                      sorted by size
  89  * @allocated_buffers:  rb tree of allocated buffers sorted by address
  90  * @free_async_space:   VA space available for async buffers. This is
  91  *                      initialized at mmap time to 1/2 the full VA space
  92  * @pages:              array of binder_lru_page
  93  * @buffer_size:        size of address space specified via mmap
  94  * @pid:                pid for associated binder_proc (invariant after init)
  95  * @pages_high:         high watermark of offset in @pages
  96  *
  97  * Bookkeeping structure for per-proc address space management for binder
  98  * buffers. It is normally initialized during binder_init() and binder_mmap()
  99  * calls. The address space is used for both user-visible buffers and for
 100  * struct binder_buffer objects used to track the user buffers
 101  */
 102 struct binder_alloc {
 103         struct mutex mutex;
 104         struct vm_area_struct *vma;
 105         struct mm_struct *vma_vm_mm;
 106         void *buffer;
 107         ptrdiff_t user_buffer_offset;
 108         struct list_head buffers;
 109         struct rb_root free_buffers;
 110         struct rb_root allocated_buffers;
 111         size_t free_async_space;
 112         struct binder_lru_page *pages;
 113         size_t buffer_size;
 114         uint32_t buffer_free;
 115         int pid;
 116         size_t pages_high;
 117 };
 118
 119 #ifdef CONFIG_ANDROID_BINDER_IPC_SELFTEST
 120 void binder_selftest_alloc(struct binder_alloc *alloc);
 121 #else
 122 static inline void binder_selftest_alloc(struct binder_alloc *alloc) {}
 123 #endif
 124 enum lru_status binder_alloc_free_page(struct list_head *item,
 125                                        struct list_lru_one *lru,
 126                                        spinlock_t *lock, void *cb_arg);
 127 extern struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 128                                                   size_t data_size,
 129                                                   size_t offsets_size,
 130                                                   size_t extra_buffers_size,
 131                                                   int is_async);
 132 extern void binder_alloc_init(struct binder_alloc *alloc);
 133 extern int binder_alloc_shrinker_init(void);
 134 extern void binder_alloc_vma_close(struct binder_alloc *alloc);
 135 extern struct binder_buffer *
 136 binder_alloc_prepare_to_free(struct binder_alloc *alloc,
 137                              uintptr_t user_ptr);
 138 extern void binder_alloc_free_buf(struct binder_alloc *alloc,
 139                                   struct binder_buffer *buffer);
 140 extern int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 141                                      struct vm_area_struct *vma);
 142 extern void binder_alloc_deferred_release(struct binder_alloc *alloc);
 143 extern int binder_alloc_get_allocated_count(struct binder_alloc *alloc);
 144 extern void binder_alloc_print_allocated(struct seq_file *m,
 145                                          struct binder_alloc *alloc);
 146 void binder_alloc_print_pages(struct seq_file *m,
 147                               struct binder_alloc *alloc);
 148
 149 /**
 150  * binder_alloc_get_free_async_space() - get free space available for async
 151  * @alloc:      binder_alloc for this proc
 152  *
 153  * Return:      the bytes remaining in the address-space for async transactions
 154  */
 155 static inline size_t
 156 binder_alloc_get_free_async_space(struct binder_alloc *alloc)
 157 {
 158         size_t free_async_space;
 159
 160         mutex_lock(&alloc->mutex);
 161         free_async_space = alloc->free_async_space;
 162         mutex_unlock(&alloc->mutex);
 163         return free_async_space;
 164 }
 165
 166 /**
 167  * binder_alloc_get_user_buffer_offset() - get offset between kernel/user addrs
 168  * @alloc:      binder_alloc for this proc
 169  *
 170  * Return:      the offset between kernel and user-space addresses to use for
 171  * virtual address conversion
 172  */
 173 static inline ptrdiff_t
 174 binder_alloc_get_user_buffer_offset(struct binder_alloc *alloc)
 175 {
 176         /*
 177          * user_buffer_offset is constant if vma is set and
 178          * undefined if vma is not set. It is possible to
 179          * get here with !alloc->vma if the target process
 180          * is dying while a transaction is being initiated.
 181          * Returning the old value is ok in this case and
 182          * the transaction will fail.
 183          */
 184         return alloc->user_buffer_offset;
 185 }
 186
 187 #endif /* _LINUX_BINDER_ALLOC_H */
 188