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 #include <uapi/linux/android/binder.h>
26 
27 extern struct list_lru binder_alloc_lru;
28 struct binder_transaction;
29 
30 /**
31  * struct binder_buffer - buffer used for binder transactions
32  * @entry:              entry alloc->buffers
33  * @rb_node:            node for allocated_buffers/free_buffers rb trees
34  * @free:               %true if buffer is free
35  * @allow_user_free:    %true if user is allowed to free buffer
36  * @async_transaction:  %true if buffer is in use for an async txn
37  * @debug_id:           unique ID for debugging
38  * @transaction:        pointer to associated struct binder_transaction
39  * @target_node:        struct binder_node associated with this buffer
40  * @data_size:          size of @transaction data
41  * @offsets_size:       size of array of offsets
42  * @extra_buffers_size: size of space for other objects (like sg lists)
43  * @user_data:          user pointer to base of buffer space
44  *
45  * Bookkeeping structure for binder transaction buffers
46  */
47 struct binder_buffer {
48 	struct list_head entry; /* free and allocated entries by address */
49 	struct rb_node rb_node; /* free entry by size or allocated entry */
50 				/* by address */
51 	unsigned free:1;
52 	unsigned allow_user_free:1;
53 	unsigned async_transaction:1;
54 	unsigned debug_id:29;
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 __user *user_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  * @buffers:            list of all buffers for this proc
86  * @free_buffers:       rb tree of buffers available for allocation
87  *                      sorted by size
88  * @allocated_buffers:  rb tree of allocated buffers sorted by address
89  * @free_async_space:   VA space available for async buffers. This is
90  *                      initialized at mmap time to 1/2 the full VA space
91  * @pages:              array of binder_lru_page
92  * @buffer_size:        size of address space specified via mmap
93  * @pid:                pid for associated binder_proc (invariant after init)
94  * @pages_high:         high watermark of offset in @pages
95  *
96  * Bookkeeping structure for per-proc address space management for binder
97  * buffers. It is normally initialized during binder_init() and binder_mmap()
98  * calls. The address space is used for both user-visible buffers and for
99  * struct binder_buffer objects used to track the user buffers
100  */
101 struct binder_alloc {
102 	struct mutex mutex;
103 	struct vm_area_struct *vma;
104 	struct mm_struct *vma_vm_mm;
105 	void __user *buffer;
106 	struct list_head buffers;
107 	struct rb_root free_buffers;
108 	struct rb_root allocated_buffers;
109 	size_t free_async_space;
110 	struct binder_lru_page *pages;
111 	size_t buffer_size;
112 	uint32_t buffer_free;
113 	int pid;
114 	size_t pages_high;
115 };
116 
117 #ifdef CONFIG_ANDROID_BINDER_IPC_SELFTEST
118 void binder_selftest_alloc(struct binder_alloc *alloc);
119 #else
120 static inline void binder_selftest_alloc(struct binder_alloc *alloc) {}
121 #endif
122 enum lru_status binder_alloc_free_page(struct list_head *item,
123 				       struct list_lru_one *lru,
124 				       spinlock_t *lock, void *cb_arg);
125 extern struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
126 						  size_t data_size,
127 						  size_t offsets_size,
128 						  size_t extra_buffers_size,
129 						  int is_async);
130 extern void binder_alloc_init(struct binder_alloc *alloc);
131 extern int binder_alloc_shrinker_init(void);
132 extern void binder_alloc_vma_close(struct binder_alloc *alloc);
133 extern struct binder_buffer *
134 binder_alloc_prepare_to_free(struct binder_alloc *alloc,
135 			     uintptr_t user_ptr);
136 extern void binder_alloc_free_buf(struct binder_alloc *alloc,
137 				  struct binder_buffer *buffer);
138 extern int binder_alloc_mmap_handler(struct binder_alloc *alloc,
139 				     struct vm_area_struct *vma);
140 extern void binder_alloc_deferred_release(struct binder_alloc *alloc);
141 extern int binder_alloc_get_allocated_count(struct binder_alloc *alloc);
142 extern void binder_alloc_print_allocated(struct seq_file *m,
143 					 struct binder_alloc *alloc);
144 void binder_alloc_print_pages(struct seq_file *m,
145 			      struct binder_alloc *alloc);
146 
147 /**
148  * binder_alloc_get_free_async_space() - get free space available for async
149  * @alloc:	binder_alloc for this proc
150  *
151  * Return:	the bytes remaining in the address-space for async transactions
152  */
153 static inline size_t
154 binder_alloc_get_free_async_space(struct binder_alloc *alloc)
155 {
156 	size_t free_async_space;
157 
158 	mutex_lock(&alloc->mutex);
159 	free_async_space = alloc->free_async_space;
160 	mutex_unlock(&alloc->mutex);
161 	return free_async_space;
162 }
163 
164 unsigned long
165 binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
166 				 struct binder_buffer *buffer,
167 				 binder_size_t buffer_offset,
168 				 const void __user *from,
169 				 size_t bytes);
170 
171 void binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
172 				 struct binder_buffer *buffer,
173 				 binder_size_t buffer_offset,
174 				 void *src,
175 				 size_t bytes);
176 
177 void binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
178 				   void *dest,
179 				   struct binder_buffer *buffer,
180 				   binder_size_t buffer_offset,
181 				   size_t bytes);
182 
183 #endif /* _LINUX_BINDER_ALLOC_H */
184 
185