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 25 struct binder_transaction; 26 27 /** 28 * struct binder_buffer - buffer used for binder transactions 29 * @entry: entry alloc->buffers 30 * @rb_node: node for allocated_buffers/free_buffers rb trees 31 * @free: true if buffer is free 32 * @allow_user_free: describe the second member of struct blah, 33 * @async_transaction: describe the second member of struct blah, 34 * @debug_id: describe the second member of struct blah, 35 * @transaction: describe the second member of struct blah, 36 * @target_node: describe the second member of struct blah, 37 * @data_size: describe the second member of struct blah, 38 * @offsets_size: describe the second member of struct blah, 39 * @extra_buffers_size: describe the second member of struct blah, 40 * @data:i describe the second member of struct blah, 41 * 42 * Bookkeeping structure for binder transaction buffers 43 */ 44 struct binder_buffer { 45 struct list_head entry; /* free and allocated entries by address */ 46 struct rb_node rb_node; /* free entry by size or allocated entry */ 47 /* by address */ 48 unsigned free:1; 49 unsigned allow_user_free:1; 50 unsigned async_transaction:1; 51 unsigned free_in_progress:1; 52 unsigned debug_id:28; 53 54 struct binder_transaction *transaction; 55 56 struct binder_node *target_node; 57 size_t data_size; 58 size_t offsets_size; 59 size_t extra_buffers_size; 60 uint8_t data[0]; 61 }; 62 63 /** 64 * struct binder_alloc - per-binder proc state for binder allocator 65 * @vma: vm_area_struct passed to mmap_handler 66 * (invarient after mmap) 67 * @tsk: tid for task that called init for this proc 68 * (invariant after init) 69 * @vma_vm_mm: copy of vma->vm_mm (invarient after mmap) 70 * @buffer: base of per-proc address space mapped via mmap 71 * @user_buffer_offset: offset between user and kernel VAs for buffer 72 * @buffers: list of all buffers for this proc 73 * @free_buffers: rb tree of buffers available for allocation 74 * sorted by size 75 * @allocated_buffers: rb tree of allocated buffers sorted by address 76 * @free_async_space: VA space available for async buffers. This is 77 * initialized at mmap time to 1/2 the full VA space 78 * @pages: array of physical page addresses for each 79 * page of mmap'd space 80 * @buffer_size: size of address space specified via mmap 81 * @pid: pid for associated binder_proc (invariant after init) 82 * 83 * Bookkeeping structure for per-proc address space management for binder 84 * buffers. It is normally initialized during binder_init() and binder_mmap() 85 * calls. The address space is used for both user-visible buffers and for 86 * struct binder_buffer objects used to track the user buffers 87 */ 88 struct binder_alloc { 89 struct mutex mutex; 90 struct task_struct *tsk; 91 struct vm_area_struct *vma; 92 struct mm_struct *vma_vm_mm; 93 void *buffer; 94 ptrdiff_t user_buffer_offset; 95 struct list_head buffers; 96 struct rb_root free_buffers; 97 struct rb_root allocated_buffers; 98 size_t free_async_space; 99 struct page **pages; 100 size_t buffer_size; 101 uint32_t buffer_free; 102 int pid; 103 }; 104 105 extern struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc, 106 size_t data_size, 107 size_t offsets_size, 108 size_t extra_buffers_size, 109 int is_async); 110 extern void binder_alloc_init(struct binder_alloc *alloc); 111 extern void binder_alloc_vma_close(struct binder_alloc *alloc); 112 extern struct binder_buffer * 113 binder_alloc_prepare_to_free(struct binder_alloc *alloc, 114 uintptr_t user_ptr); 115 extern void binder_alloc_free_buf(struct binder_alloc *alloc, 116 struct binder_buffer *buffer); 117 extern int binder_alloc_mmap_handler(struct binder_alloc *alloc, 118 struct vm_area_struct *vma); 119 extern void binder_alloc_deferred_release(struct binder_alloc *alloc); 120 extern int binder_alloc_get_allocated_count(struct binder_alloc *alloc); 121 extern void binder_alloc_print_allocated(struct seq_file *m, 122 struct binder_alloc *alloc); 123 124 /** 125 * binder_alloc_get_free_async_space() - get free space available for async 126 * @alloc: binder_alloc for this proc 127 * 128 * Return: the bytes remaining in the address-space for async transactions 129 */ 130 static inline size_t 131 binder_alloc_get_free_async_space(struct binder_alloc *alloc) 132 { 133 size_t free_async_space; 134 135 mutex_lock(&alloc->mutex); 136 free_async_space = alloc->free_async_space; 137 mutex_unlock(&alloc->mutex); 138 return free_async_space; 139 } 140 141 /** 142 * binder_alloc_get_user_buffer_offset() - get offset between kernel/user addrs 143 * @alloc: binder_alloc for this proc 144 * 145 * Return: the offset between kernel and user-space addresses to use for 146 * virtual address conversion 147 */ 148 static inline ptrdiff_t 149 binder_alloc_get_user_buffer_offset(struct binder_alloc *alloc) 150 { 151 /* 152 * user_buffer_offset is constant if vma is set and 153 * undefined if vma is not set. It is possible to 154 * get here with !alloc->vma if the target process 155 * is dying while a transaction is being initiated. 156 * Returning the old value is ok in this case and 157 * the transaction will fail. 158 */ 159 return alloc->user_buffer_offset; 160 } 161 162 #endif /* _LINUX_BINDER_ALLOC_H */ 163 164