binder_alloc.h

  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
 18struct binder_transaction;
 19
 20/**
 21 * struct binder_buffer - buffer used for binder transactions
 22 * @entry:              entry alloc->buffers
 23 * @rb_node:            node for allocated_buffers/free_buffers rb trees
 24 * @free:               %true if buffer is free
 25 * @clear_on_free:      %true if buffer must be zeroed after use
 26 * @allow_user_free:    %true if user is allowed to free buffer
 27 * @async_transaction:  %true if buffer is in use for an async txn
 28 * @oneway_spam_suspect: %true if total async allocate size just exceed
 29 * spamming detect threshold
 30 * @debug_id:           unique ID for debugging
 31 * @transaction:        pointer to associated struct binder_transaction
 32 * @target_node:        struct binder_node associated with this buffer
 33 * @data_size:          size of @transaction data
 34 * @offsets_size:       size of array of offsets
 35 * @extra_buffers_size: size of space for other objects (like sg lists)
 36 * @user_data:          user pointer to base of buffer space
 37 * @pid:                pid to attribute the buffer to (caller)
 38 *
 39 * Bookkeeping structure for binder transaction buffers
 40 */
 41struct binder_buffer {
 42	struct list_head entry; /* free and allocated entries by address */
 43	struct rb_node rb_node; /* free entry by size or allocated entry */
 44				/* by address */
 45	unsigned free:1;
 46	unsigned clear_on_free:1;
 47	unsigned allow_user_free:1;
 48	unsigned async_transaction:1;
 49	unsigned oneway_spam_suspect:1;
 50	unsigned debug_id:27;
 51	struct binder_transaction *transaction;
 52	struct binder_node *target_node;
 53	size_t data_size;
 54	size_t offsets_size;
 55	size_t extra_buffers_size;
 56	unsigned long user_data;
 57	int pid;
 58};
 59
 60/**
 61 * struct binder_shrinker_mdata - binder metadata used to reclaim pages
 62 * @lru:         LRU entry in binder_freelist
 63 * @alloc:       binder_alloc owning the page to reclaim
 64 * @page_index:  offset in @alloc->pages[] into the page to reclaim
 65 */
 66struct binder_shrinker_mdata {
 67	struct list_head lru;
 68	struct binder_alloc *alloc;
 69	unsigned long page_index;
 70};
 71
 72static inline struct list_head *page_to_lru(struct page *p)
 73{
 74	struct binder_shrinker_mdata *mdata;
 75
 76	mdata = (struct binder_shrinker_mdata *)page_private(p);
 77
 78	return &mdata->lru;
 79}
 80
 81/**
 82 * struct binder_alloc - per-binder proc state for binder allocator
 83 * @mutex:              protects binder_alloc fields
 84 * @mm:                 copy of task->mm (invariant after open)
 85 * @vm_start:           base of per-proc address space mapped via mmap
 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 struct page *
 93 * @freelist:           lru list to use for free pages (invariant after init)
 94 * @buffer_size:        size of address space specified via mmap
 95 * @pid:                pid for associated binder_proc (invariant after init)
 96 * @pages_high:         high watermark of offset in @pages
 97 * @mapped:             whether the vm area is mapped, each binder instance is
 98 *                      allowed a single mapping throughout its lifetime
 99 * @oneway_spam_detected: %true if oneway spam detection fired, clear that
100 * flag once the async buffer has returned to a healthy state
101 *
102 * Bookkeeping structure for per-proc address space management for binder
103 * buffers. It is normally initialized during binder_init() and binder_mmap()
104 * calls. The address space is used for both user-visible buffers and for
105 * struct binder_buffer objects used to track the user buffers
106 */
107struct binder_alloc {
108	struct mutex mutex;
109	struct mm_struct *mm;
110	unsigned long vm_start;
111	struct list_head buffers;
112	struct rb_root free_buffers;
113	struct rb_root allocated_buffers;
114	size_t free_async_space;
115	struct page **pages;
116	struct list_lru *freelist;
117	size_t buffer_size;
118	int pid;
119	size_t pages_high;
120	bool mapped;
121	bool oneway_spam_detected;
122};
123
124enum lru_status binder_alloc_free_page(struct list_head *item,
125				       struct list_lru_one *lru,
126				       void *cb_arg);
127struct 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);
132void binder_alloc_init(struct binder_alloc *alloc);
133int binder_alloc_shrinker_init(void);
134void binder_alloc_shrinker_exit(void);
135void binder_alloc_vma_close(struct binder_alloc *alloc);
136struct binder_buffer *
137binder_alloc_prepare_to_free(struct binder_alloc *alloc,
138			     unsigned long user_ptr);
139void binder_alloc_free_buf(struct binder_alloc *alloc,
140			   struct binder_buffer *buffer);
141int binder_alloc_mmap_handler(struct binder_alloc *alloc,
142			      struct vm_area_struct *vma);
143void binder_alloc_deferred_release(struct binder_alloc *alloc);
144int binder_alloc_get_allocated_count(struct binder_alloc *alloc);
145void binder_alloc_print_allocated(struct seq_file *m,
146				  struct binder_alloc *alloc);
147void binder_alloc_print_pages(struct seq_file *m,
148			      struct binder_alloc *alloc);
149
150/**
151 * binder_alloc_get_free_async_space() - get free space available for async
152 * @alloc:	binder_alloc for this proc
153 *
154 * Return:	the bytes remaining in the address-space for async transactions
155 */
156static inline size_t
157binder_alloc_get_free_async_space(struct binder_alloc *alloc)
158{
159	guard(mutex)(&alloc->mutex);
160	return alloc->free_async_space;
161}
162
163unsigned long
164binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
165				 struct binder_buffer *buffer,
166				 binder_size_t buffer_offset,
167				 const void __user *from,
168				 size_t bytes);
169
170int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
171				struct binder_buffer *buffer,
172				binder_size_t buffer_offset,
173				void *src,
174				size_t bytes);
175
176int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
177				  void *dest,
178				  struct binder_buffer *buffer,
179				  binder_size_t buffer_offset,
180				  size_t bytes);
181
182#if IS_ENABLED(CONFIG_KUNIT)
183void __binder_alloc_init(struct binder_alloc *alloc, struct list_lru *freelist);
184size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
185				struct binder_buffer *buffer);
186#endif
187
188#endif /* _LINUX_BINDER_ALLOC_H */
189