1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2017 Google, Inc.
4  */
5 
6 #ifndef _LINUX_BINDER_ALLOC_H
7 #define _LINUX_BINDER_ALLOC_H
8 
9 #include <linux/rbtree.h>
10 #include <linux/list.h>
11 #include <linux/mm.h>
12 #include <linux/rtmutex.h>
13 #include <linux/vmalloc.h>
14 #include <linux/slab.h>
15 #include <linux/list_lru.h>
16 #include <uapi/linux/android/binder.h>
17 
18 extern struct list_lru binder_alloc_lru;
19 struct binder_transaction;
20 
21 /**
22  * struct binder_buffer - buffer used for binder transactions
23  * @entry:              entry alloc->buffers
24  * @rb_node:            node for allocated_buffers/free_buffers rb trees
25  * @free:               %true if buffer is free
26  * @clear_on_free:      %true if buffer must be zeroed after use
27  * @allow_user_free:    %true if user is allowed to free buffer
28  * @async_transaction:  %true if buffer is in use for an async txn
29  * @oneway_spam_suspect: %true if total async allocate size just exceed
30  * spamming detect threshold
31  * @debug_id:           unique ID for debugging
32  * @transaction:        pointer to associated struct binder_transaction
33  * @target_node:        struct binder_node associated with this buffer
34  * @data_size:          size of @transaction data
35  * @offsets_size:       size of array of offsets
36  * @extra_buffers_size: size of space for other objects (like sg lists)
37  * @user_data:          user pointer to base of buffer space
38  * @pid:                pid to attribute the buffer to (caller)
39  *
40  * Bookkeeping structure for binder transaction buffers
41  */
42 struct binder_buffer {
43 	struct list_head entry; /* free and allocated entries by address */
44 	struct rb_node rb_node; /* free entry by size or allocated entry */
45 				/* by address */
46 	unsigned free:1;
47 	unsigned clear_on_free:1;
48 	unsigned allow_user_free:1;
49 	unsigned async_transaction:1;
50 	unsigned oneway_spam_suspect:1;
51 	unsigned debug_id:27;
52 
53 	struct binder_transaction *transaction;
54 
55 	struct binder_node *target_node;
56 	size_t data_size;
57 	size_t offsets_size;
58 	size_t extra_buffers_size;
59 	void __user *user_data;
60 	int    pid;
61 };
62 
63 /**
64  * struct binder_lru_page - page object used for binder shrinker
65  * @page_ptr: pointer to physical page in mmap'd space
66  * @lru:      entry in binder_alloc_lru
67  * @alloc:    binder_alloc for a proc
68  */
69 struct binder_lru_page {
70 	struct list_head lru;
71 	struct page *page_ptr;
72 	struct binder_alloc *alloc;
73 };
74 
75 /**
76  * struct binder_alloc - per-binder proc state for binder allocator
77  * @mutex:              protects binder_alloc fields
78  * @vma:                vm_area_struct passed to mmap_handler
79  *                      (invariant after mmap)
80  * @mm:                 copy of task->mm (invariant after open)
81  * @buffer:             base of per-proc address space mapped via mmap
82  * @buffers:            list of all buffers for this proc
83  * @free_buffers:       rb tree of buffers available for allocation
84  *                      sorted by size
85  * @allocated_buffers:  rb tree of allocated buffers sorted by address
86  * @free_async_space:   VA space available for async buffers. This is
87  *                      initialized at mmap time to 1/2 the full VA space
88  * @pages:              array of binder_lru_page
89  * @buffer_size:        size of address space specified via mmap
90  * @pid:                pid for associated binder_proc (invariant after init)
91  * @pages_high:         high watermark of offset in @pages
92  * @oneway_spam_detected: %true if oneway spam detection fired, clear that
93  * flag once the async buffer has returned to a healthy state
94  *
95  * Bookkeeping structure for per-proc address space management for binder
96  * buffers. It is normally initialized during binder_init() and binder_mmap()
97  * calls. The address space is used for both user-visible buffers and for
98  * struct binder_buffer objects used to track the user buffers
99  */
100 struct binder_alloc {
101 	struct mutex mutex;
102 	struct vm_area_struct *vma;
103 	struct mm_struct *mm;
104 	void __user *buffer;
105 	struct list_head buffers;
106 	struct rb_root free_buffers;
107 	struct rb_root allocated_buffers;
108 	size_t free_async_space;
109 	struct binder_lru_page *pages;
110 	size_t buffer_size;
111 	int pid;
112 	size_t pages_high;
113 	bool oneway_spam_detected;
114 };
115 
116 #ifdef CONFIG_ANDROID_BINDER_IPC_SELFTEST
117 void binder_selftest_alloc(struct binder_alloc *alloc);
118 #else
binder_selftest_alloc(struct binder_alloc * alloc)119 static inline void binder_selftest_alloc(struct binder_alloc *alloc) {}
120 #endif
121 enum lru_status binder_alloc_free_page(struct list_head *item,
122 				       struct list_lru_one *lru,
123 				       spinlock_t *lock, void *cb_arg);
124 extern struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
125 						  size_t data_size,
126 						  size_t offsets_size,
127 						  size_t extra_buffers_size,
128 						  int is_async,
129 						  int pid);
130 extern void binder_alloc_init(struct binder_alloc *alloc);
131 extern int binder_alloc_shrinker_init(void);
132 extern void binder_alloc_shrinker_exit(void);
133 extern void binder_alloc_vma_close(struct binder_alloc *alloc);
134 extern struct binder_buffer *
135 binder_alloc_prepare_to_free(struct binder_alloc *alloc,
136 			     uintptr_t user_ptr);
137 extern void binder_alloc_free_buf(struct binder_alloc *alloc,
138 				  struct binder_buffer *buffer);
139 extern int binder_alloc_mmap_handler(struct binder_alloc *alloc,
140 				     struct vm_area_struct *vma);
141 extern void binder_alloc_deferred_release(struct binder_alloc *alloc);
142 extern int binder_alloc_get_allocated_count(struct binder_alloc *alloc);
143 extern void binder_alloc_print_allocated(struct seq_file *m,
144 					 struct binder_alloc *alloc);
145 void binder_alloc_print_pages(struct seq_file *m,
146 			      struct binder_alloc *alloc);
147 
148 /**
149  * binder_alloc_get_free_async_space() - get free space available for async
150  * @alloc:	binder_alloc for this proc
151  *
152  * Return:	the bytes remaining in the address-space for async transactions
153  */
154 static inline size_t
binder_alloc_get_free_async_space(struct binder_alloc * alloc)155 binder_alloc_get_free_async_space(struct binder_alloc *alloc)
156 {
157 	size_t free_async_space;
158 
159 	mutex_lock(&alloc->mutex);
160 	free_async_space = alloc->free_async_space;
161 	mutex_unlock(&alloc->mutex);
162 	return free_async_space;
163 }
164 
165 unsigned long
166 binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
167 				 struct binder_buffer *buffer,
168 				 binder_size_t buffer_offset,
169 				 const void __user *from,
170 				 size_t bytes);
171 
172 int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
173 				struct binder_buffer *buffer,
174 				binder_size_t buffer_offset,
175 				void *src,
176 				size_t bytes);
177 
178 int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
179 				  void *dest,
180 				  struct binder_buffer *buffer,
181 				  binder_size_t buffer_offset,
182 				  size_t bytes);
183 
184 #endif /* _LINUX_BINDER_ALLOC_H */
185 
186