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
 26extern struct list_lru binder_alloc_lru;
 27struct 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 */
 46struct 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 */
 71struct 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 */
102struct 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
120void binder_selftest_alloc(struct binder_alloc *alloc);
121#else
122static inline void binder_selftest_alloc(struct binder_alloc *alloc) {}
123#endif
124enum lru_status binder_alloc_free_page(struct list_head *item,
125				       struct list_lru_one *lru,
126				       spinlock_t *lock, void *cb_arg);
127extern 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);
132extern void binder_alloc_init(struct binder_alloc *alloc);
133extern int binder_alloc_shrinker_init(void);
134extern void binder_alloc_vma_close(struct binder_alloc *alloc);
135extern struct binder_buffer *
136binder_alloc_prepare_to_free(struct binder_alloc *alloc,
137			     uintptr_t user_ptr);
138extern void binder_alloc_free_buf(struct binder_alloc *alloc,
139				  struct binder_buffer *buffer);
140extern int binder_alloc_mmap_handler(struct binder_alloc *alloc,
141				     struct vm_area_struct *vma);
142extern void binder_alloc_deferred_release(struct binder_alloc *alloc);
143extern int binder_alloc_get_allocated_count(struct binder_alloc *alloc);
144extern void binder_alloc_print_allocated(struct seq_file *m,
145					 struct binder_alloc *alloc);
146void 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 */
155static inline size_t
156binder_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 */
173static inline ptrdiff_t
174binder_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