Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 1 | /* mm/ashmem.c |
Cruz Julian Bishop | 2258937 | 2012-08-01 14:54:16 +1000 | [diff] [blame] | 2 | * |
| 3 | * Anonymous Shared Memory Subsystem, ashmem |
| 4 | * |
| 5 | * Copyright (C) 2008 Google, Inc. |
| 6 | * |
| 7 | * Robert Love <rlove@google.com> |
| 8 | * |
| 9 | * This software is licensed under the terms of the GNU General Public |
| 10 | * License version 2, as published by the Free Software Foundation, and |
| 11 | * may be copied, distributed, and modified under those terms. |
| 12 | * |
| 13 | * This program is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | * GNU General Public License for more details. |
| 17 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 18 | |
Sachin Kamat | c810a39 | 2012-06-05 16:40:10 +0530 | [diff] [blame] | 19 | #define pr_fmt(fmt) "ashmem: " fmt |
| 20 | |
Paul Gortmaker | 12950595 | 2015-10-11 15:47:28 -0400 | [diff] [blame] | 21 | #include <linux/init.h> |
| 22 | #include <linux/export.h> |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 23 | #include <linux/file.h> |
| 24 | #include <linux/fs.h> |
Hugh Dickins | 3f31d07 | 2012-05-29 15:06:40 -0700 | [diff] [blame] | 25 | #include <linux/falloc.h> |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 26 | #include <linux/miscdevice.h> |
| 27 | #include <linux/security.h> |
| 28 | #include <linux/mm.h> |
| 29 | #include <linux/mman.h> |
| 30 | #include <linux/uaccess.h> |
| 31 | #include <linux/personality.h> |
| 32 | #include <linux/bitops.h> |
| 33 | #include <linux/mutex.h> |
| 34 | #include <linux/shmem_fs.h> |
| 35 | #include "ashmem.h" |
| 36 | |
| 37 | #define ASHMEM_NAME_PREFIX "dev/ashmem/" |
| 38 | #define ASHMEM_NAME_PREFIX_LEN (sizeof(ASHMEM_NAME_PREFIX) - 1) |
| 39 | #define ASHMEM_FULL_NAME_LEN (ASHMEM_NAME_LEN + ASHMEM_NAME_PREFIX_LEN) |
| 40 | |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 41 | /** |
| 42 | * struct ashmem_area - The anonymous shared memory area |
| 43 | * @name: The optional name in /proc/pid/maps |
| 44 | * @unpinned_list: The list of all ashmem areas |
| 45 | * @file: The shmem-based backing file |
| 46 | * @size: The size of the mapping, in bytes |
Cristina Moraru | 7d92ea5 | 2015-10-03 18:20:47 +0300 | [diff] [blame] | 47 | * @prot_mask: The allowed protection bits, as vm_flags |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 48 | * |
| 49 | * The lifecycle of this structure is from our parent file's open() until |
| 50 | * its release(). It is also protected by 'ashmem_mutex' |
| 51 | * |
| 52 | * Warning: Mappings do NOT pin this structure; It dies on close() |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 53 | */ |
| 54 | struct ashmem_area { |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 55 | char name[ASHMEM_FULL_NAME_LEN]; |
| 56 | struct list_head unpinned_list; |
| 57 | struct file *file; |
| 58 | size_t size; |
| 59 | unsigned long prot_mask; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 60 | }; |
| 61 | |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 62 | /** |
| 63 | * struct ashmem_range - A range of unpinned/evictable pages |
| 64 | * @lru: The entry in the LRU list |
| 65 | * @unpinned: The entry in its area's unpinned list |
| 66 | * @asma: The associated anonymous shared memory area. |
| 67 | * @pgstart: The starting page (inclusive) |
| 68 | * @pgend: The ending page (inclusive) |
| 69 | * @purged: The purge status (ASHMEM_NOT or ASHMEM_WAS_PURGED) |
| 70 | * |
| 71 | * The lifecycle of this structure is from unpin to pin. |
| 72 | * It is protected by 'ashmem_mutex' |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 73 | */ |
| 74 | struct ashmem_range { |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 75 | struct list_head lru; |
| 76 | struct list_head unpinned; |
| 77 | struct ashmem_area *asma; |
| 78 | size_t pgstart; |
| 79 | size_t pgend; |
| 80 | unsigned int purged; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 81 | }; |
| 82 | |
| 83 | /* LRU list of unpinned pages, protected by ashmem_mutex */ |
| 84 | static LIST_HEAD(ashmem_lru_list); |
| 85 | |
Cristina Moraru | 801b798 | 2015-10-03 18:45:01 +0300 | [diff] [blame] | 86 | /* |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 87 | * long lru_count - The count of pages on our LRU list. |
| 88 | * |
| 89 | * This is protected by ashmem_mutex. |
| 90 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 91 | static unsigned long lru_count; |
| 92 | |
Cristina Moraru | 801b798 | 2015-10-03 18:45:01 +0300 | [diff] [blame] | 93 | /* |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 94 | * ashmem_mutex - protects the list of and each individual ashmem_area |
| 95 | * |
| 96 | * Lock Ordering: ashmex_mutex -> i_mutex -> i_alloc_sem |
| 97 | */ |
| 98 | static DEFINE_MUTEX(ashmem_mutex); |
| 99 | |
| 100 | static struct kmem_cache *ashmem_area_cachep __read_mostly; |
| 101 | static struct kmem_cache *ashmem_range_cachep __read_mostly; |
| 102 | |
| 103 | #define range_size(range) \ |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 104 | ((range)->pgend - (range)->pgstart + 1) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 105 | |
| 106 | #define range_on_lru(range) \ |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 107 | ((range)->purged == ASHMEM_NOT_PURGED) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 108 | |
Bhumika Goyal | c0ece6c | 2016-03-11 19:33:05 +0530 | [diff] [blame] | 109 | static inline int page_range_subsumes_range(struct ashmem_range *range, |
| 110 | size_t start, size_t end) |
| 111 | { |
| 112 | return (((range)->pgstart >= (start)) && ((range)->pgend <= (end))); |
| 113 | } |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 114 | |
Bhumika Goyal | c0ece6c | 2016-03-11 19:33:05 +0530 | [diff] [blame] | 115 | static inline int page_range_subsumed_by_range(struct ashmem_range *range, |
| 116 | size_t start, size_t end) |
| 117 | { |
| 118 | return (((range)->pgstart <= (start)) && ((range)->pgend >= (end))); |
| 119 | } |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 120 | |
Bhumika Goyal | e2a83f3 | 2016-03-11 19:33:04 +0530 | [diff] [blame] | 121 | static inline int page_in_range(struct ashmem_range *range, size_t page) |
| 122 | { |
| 123 | return (((range)->pgstart <= (page)) && ((range)->pgend >= (page))); |
| 124 | } |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 125 | |
Bhumika Goyal | c0ece6c | 2016-03-11 19:33:05 +0530 | [diff] [blame] | 126 | static inline int page_range_in_range(struct ashmem_range *range, |
| 127 | size_t start, size_t end) |
| 128 | { |
| 129 | return (page_in_range(range, start) || page_in_range(range, end) || |
| 130 | page_range_subsumes_range(range, start, end)); |
| 131 | } |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 132 | |
Bhumika Goyal | e2a83f3 | 2016-03-11 19:33:04 +0530 | [diff] [blame] | 133 | static inline int range_before_page(struct ashmem_range *range, size_t page) |
| 134 | { |
| 135 | return ((range)->pgend < (page)); |
| 136 | } |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 137 | |
| 138 | #define PROT_MASK (PROT_EXEC | PROT_READ | PROT_WRITE) |
| 139 | |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 140 | /** |
| 141 | * lru_add() - Adds a range of memory to the LRU list |
| 142 | * @range: The memory range being added. |
| 143 | * |
| 144 | * The range is first added to the end (tail) of the LRU list. |
| 145 | * After this, the size of the range is added to @lru_count |
| 146 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 147 | static inline void lru_add(struct ashmem_range *range) |
| 148 | { |
| 149 | list_add_tail(&range->lru, &ashmem_lru_list); |
| 150 | lru_count += range_size(range); |
| 151 | } |
| 152 | |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 153 | /** |
| 154 | * lru_del() - Removes a range of memory from the LRU list |
| 155 | * @range: The memory range being removed |
| 156 | * |
| 157 | * The range is first deleted from the LRU list. |
| 158 | * After this, the size of the range is removed from @lru_count |
| 159 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 160 | static inline void lru_del(struct ashmem_range *range) |
| 161 | { |
| 162 | list_del(&range->lru); |
| 163 | lru_count -= range_size(range); |
| 164 | } |
| 165 | |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 166 | /** |
| 167 | * range_alloc() - Allocates and initializes a new ashmem_range structure |
| 168 | * @asma: The associated ashmem_area |
| 169 | * @prev_range: The previous ashmem_range in the sorted asma->unpinned list |
| 170 | * @purged: Initial purge status (ASMEM_NOT_PURGED or ASHMEM_WAS_PURGED) |
| 171 | * @start: The starting page (inclusive) |
| 172 | * @end: The ending page (inclusive) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 173 | * |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 174 | * This function is protected by ashmem_mutex. |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 175 | * |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 176 | * Return: 0 if successful, or -ENOMEM if there is an error |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 177 | */ |
| 178 | static int range_alloc(struct ashmem_area *asma, |
| 179 | struct ashmem_range *prev_range, unsigned int purged, |
| 180 | size_t start, size_t end) |
| 181 | { |
| 182 | struct ashmem_range *range; |
| 183 | |
| 184 | range = kmem_cache_zalloc(ashmem_range_cachep, GFP_KERNEL); |
| 185 | if (unlikely(!range)) |
| 186 | return -ENOMEM; |
| 187 | |
| 188 | range->asma = asma; |
| 189 | range->pgstart = start; |
| 190 | range->pgend = end; |
| 191 | range->purged = purged; |
| 192 | |
| 193 | list_add_tail(&range->unpinned, &prev_range->unpinned); |
| 194 | |
| 195 | if (range_on_lru(range)) |
| 196 | lru_add(range); |
| 197 | |
| 198 | return 0; |
| 199 | } |
| 200 | |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 201 | /** |
| 202 | * range_del() - Deletes and dealloctes an ashmem_range structure |
| 203 | * @range: The associated ashmem_range that has previously been allocated |
| 204 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 205 | static void range_del(struct ashmem_range *range) |
| 206 | { |
| 207 | list_del(&range->unpinned); |
| 208 | if (range_on_lru(range)) |
| 209 | lru_del(range); |
| 210 | kmem_cache_free(ashmem_range_cachep, range); |
| 211 | } |
| 212 | |
Cruz Julian Bishop | 781114c | 2013-09-03 22:05:08 +1000 | [diff] [blame] | 213 | /** |
| 214 | * range_shrink() - Shrinks an ashmem_range |
| 215 | * @range: The associated ashmem_range being shrunk |
| 216 | * @start: The starting byte of the new range |
| 217 | * @end: The ending byte of the new range |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 218 | * |
Cruz Julian Bishop | 781114c | 2013-09-03 22:05:08 +1000 | [diff] [blame] | 219 | * This does not modify the data inside the existing range in any way - It |
| 220 | * simply shrinks the boundaries of the range. |
| 221 | * |
| 222 | * Theoretically, with a little tweaking, this could eventually be changed |
| 223 | * to range_resize, and expand the lru_count if the new range is larger. |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 224 | */ |
| 225 | static inline void range_shrink(struct ashmem_range *range, |
| 226 | size_t start, size_t end) |
| 227 | { |
| 228 | size_t pre = range_size(range); |
| 229 | |
| 230 | range->pgstart = start; |
| 231 | range->pgend = end; |
| 232 | |
| 233 | if (range_on_lru(range)) |
| 234 | lru_count -= pre - range_size(range); |
| 235 | } |
| 236 | |
Cruz Julian Bishop | 781114c | 2013-09-03 22:05:08 +1000 | [diff] [blame] | 237 | /** |
| 238 | * ashmem_open() - Opens an Anonymous Shared Memory structure |
| 239 | * @inode: The backing file's index node(?) |
| 240 | * @file: The backing file |
| 241 | * |
| 242 | * Please note that the ashmem_area is not returned by this function - It is |
| 243 | * instead written to "file->private_data". |
| 244 | * |
| 245 | * Return: 0 if successful, or another code if unsuccessful. |
| 246 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 247 | static int ashmem_open(struct inode *inode, struct file *file) |
| 248 | { |
| 249 | struct ashmem_area *asma; |
| 250 | int ret; |
| 251 | |
Bjorn Bringert | 5154b93 | 2011-12-20 16:49:52 -0800 | [diff] [blame] | 252 | ret = generic_file_open(inode, file); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 253 | if (unlikely(ret)) |
| 254 | return ret; |
| 255 | |
| 256 | asma = kmem_cache_zalloc(ashmem_area_cachep, GFP_KERNEL); |
| 257 | if (unlikely(!asma)) |
| 258 | return -ENOMEM; |
| 259 | |
| 260 | INIT_LIST_HEAD(&asma->unpinned_list); |
| 261 | memcpy(asma->name, ASHMEM_NAME_PREFIX, ASHMEM_NAME_PREFIX_LEN); |
| 262 | asma->prot_mask = PROT_MASK; |
| 263 | file->private_data = asma; |
| 264 | |
| 265 | return 0; |
| 266 | } |
| 267 | |
Cruz Julian Bishop | 781114c | 2013-09-03 22:05:08 +1000 | [diff] [blame] | 268 | /** |
| 269 | * ashmem_release() - Releases an Anonymous Shared Memory structure |
| 270 | * @ignored: The backing file's Index Node(?) - It is ignored here. |
| 271 | * @file: The backing file |
| 272 | * |
| 273 | * Return: 0 if successful. If it is anything else, go have a coffee and |
| 274 | * try again. |
| 275 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 276 | static int ashmem_release(struct inode *ignored, struct file *file) |
| 277 | { |
| 278 | struct ashmem_area *asma = file->private_data; |
| 279 | struct ashmem_range *range, *next; |
| 280 | |
| 281 | mutex_lock(&ashmem_mutex); |
| 282 | list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned) |
| 283 | range_del(range); |
| 284 | mutex_unlock(&ashmem_mutex); |
| 285 | |
| 286 | if (asma->file) |
| 287 | fput(asma->file); |
| 288 | kmem_cache_free(ashmem_area_cachep, asma); |
| 289 | |
| 290 | return 0; |
| 291 | } |
| 292 | |
Cruz Julian Bishop | 781114c | 2013-09-03 22:05:08 +1000 | [diff] [blame] | 293 | /** |
| 294 | * ashmem_read() - Reads a set of bytes from an Ashmem-enabled file |
| 295 | * @file: The associated backing file. |
| 296 | * @buf: The buffer of data being written to |
| 297 | * @len: The number of bytes being read |
| 298 | * @pos: The position of the first byte to read. |
| 299 | * |
| 300 | * Return: 0 if successful, or another return code if not. |
| 301 | */ |
Bjorn Bringert | 853ca7a | 2011-12-20 16:49:49 -0800 | [diff] [blame] | 302 | static ssize_t ashmem_read(struct file *file, char __user *buf, |
| 303 | size_t len, loff_t *pos) |
| 304 | { |
| 305 | struct ashmem_area *asma = file->private_data; |
| 306 | int ret = 0; |
| 307 | |
| 308 | mutex_lock(&ashmem_mutex); |
| 309 | |
| 310 | /* If size is not set, or set to 0, always return EOF. */ |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 311 | if (asma->size == 0) |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 312 | goto out_unlock; |
Bjorn Bringert | 853ca7a | 2011-12-20 16:49:49 -0800 | [diff] [blame] | 313 | |
| 314 | if (!asma->file) { |
| 315 | ret = -EBADF; |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 316 | goto out_unlock; |
Bjorn Bringert | 853ca7a | 2011-12-20 16:49:49 -0800 | [diff] [blame] | 317 | } |
| 318 | |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 319 | mutex_unlock(&ashmem_mutex); |
| 320 | |
| 321 | /* |
| 322 | * asma and asma->file are used outside the lock here. We assume |
| 323 | * once asma->file is set it will never be changed, and will not |
| 324 | * be destroyed until all references to the file are dropped and |
| 325 | * ashmem_release is called. |
| 326 | */ |
Al Viro | e145286 | 2015-04-03 15:09:38 -0400 | [diff] [blame] | 327 | ret = __vfs_read(asma->file, buf, len, pos); |
Shraddha Barke | 7273773 | 2015-09-05 18:58:26 +0530 | [diff] [blame] | 328 | if (ret >= 0) |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 329 | /** Update backing file pos, since f_ops->read() doesn't */ |
| 330 | asma->file->f_pos = *pos; |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 331 | return ret; |
Bjorn Bringert | 5154b93 | 2011-12-20 16:49:52 -0800 | [diff] [blame] | 332 | |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 333 | out_unlock: |
Bjorn Bringert | 5154b93 | 2011-12-20 16:49:52 -0800 | [diff] [blame] | 334 | mutex_unlock(&ashmem_mutex); |
| 335 | return ret; |
| 336 | } |
| 337 | |
| 338 | static loff_t ashmem_llseek(struct file *file, loff_t offset, int origin) |
| 339 | { |
| 340 | struct ashmem_area *asma = file->private_data; |
| 341 | int ret; |
| 342 | |
| 343 | mutex_lock(&ashmem_mutex); |
| 344 | |
| 345 | if (asma->size == 0) { |
Joel Fernandes | 1d47c87 | 2018-02-16 11:02:01 -0800 | [diff] [blame] | 346 | mutex_unlock(&ashmem_mutex); |
| 347 | return -EINVAL; |
Bjorn Bringert | 5154b93 | 2011-12-20 16:49:52 -0800 | [diff] [blame] | 348 | } |
| 349 | |
| 350 | if (!asma->file) { |
Joel Fernandes | 1d47c87 | 2018-02-16 11:02:01 -0800 | [diff] [blame] | 351 | mutex_unlock(&ashmem_mutex); |
| 352 | return -EBADF; |
Bjorn Bringert | 5154b93 | 2011-12-20 16:49:52 -0800 | [diff] [blame] | 353 | } |
| 354 | |
Joel Fernandes | 1d47c87 | 2018-02-16 11:02:01 -0800 | [diff] [blame] | 355 | mutex_unlock(&ashmem_mutex); |
| 356 | |
Al Viro | 91360b0 | 2014-08-19 11:08:22 -0400 | [diff] [blame] | 357 | ret = vfs_llseek(asma->file, offset, origin); |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 358 | if (ret < 0) |
Joel Fernandes | 1d47c87 | 2018-02-16 11:02:01 -0800 | [diff] [blame] | 359 | return ret; |
Bjorn Bringert | 5154b93 | 2011-12-20 16:49:52 -0800 | [diff] [blame] | 360 | |
| 361 | /** Copy f_pos from backing file, since f_ops->llseek() sets it */ |
| 362 | file->f_pos = asma->file->f_pos; |
Bjorn Bringert | 853ca7a | 2011-12-20 16:49:49 -0800 | [diff] [blame] | 363 | return ret; |
| 364 | } |
| 365 | |
Konstantin Khlebnikov | 7cfce77 | 2012-03-21 02:56:33 -0300 | [diff] [blame] | 366 | static inline vm_flags_t calc_vm_may_flags(unsigned long prot) |
Arve Hjønnevåg | 56f76fc | 2011-12-20 16:49:50 -0800 | [diff] [blame] | 367 | { |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 368 | return _calc_vm_trans(prot, PROT_READ, VM_MAYREAD) | |
Arve Hjønnevåg | 56f76fc | 2011-12-20 16:49:50 -0800 | [diff] [blame] | 369 | _calc_vm_trans(prot, PROT_WRITE, VM_MAYWRITE) | |
| 370 | _calc_vm_trans(prot, PROT_EXEC, VM_MAYEXEC); |
| 371 | } |
Bjorn Bringert | 853ca7a | 2011-12-20 16:49:49 -0800 | [diff] [blame] | 372 | |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 373 | static int ashmem_mmap(struct file *file, struct vm_area_struct *vma) |
| 374 | { |
| 375 | struct ashmem_area *asma = file->private_data; |
| 376 | int ret = 0; |
| 377 | |
| 378 | mutex_lock(&ashmem_mutex); |
| 379 | |
| 380 | /* user needs to SET_SIZE before mapping */ |
| 381 | if (unlikely(!asma->size)) { |
| 382 | ret = -EINVAL; |
| 383 | goto out; |
| 384 | } |
| 385 | |
| 386 | /* requested protection bits must match our allowed protection mask */ |
Dave Hansen | e6bfb70 | 2016-02-12 13:02:31 -0800 | [diff] [blame] | 387 | if (unlikely((vma->vm_flags & ~calc_vm_prot_bits(asma->prot_mask, 0)) & |
| 388 | calc_vm_prot_bits(PROT_MASK, 0))) { |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 389 | ret = -EPERM; |
| 390 | goto out; |
| 391 | } |
Arve Hjønnevåg | 56f76fc | 2011-12-20 16:49:50 -0800 | [diff] [blame] | 392 | vma->vm_flags &= ~calc_vm_may_flags(~asma->prot_mask); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 393 | |
| 394 | if (!asma->file) { |
| 395 | char *name = ASHMEM_NAME_DEF; |
| 396 | struct file *vmfile; |
| 397 | |
| 398 | if (asma->name[ASHMEM_NAME_PREFIX_LEN] != '\0') |
| 399 | name = asma->name; |
| 400 | |
| 401 | /* ... and allocate the backing shmem file */ |
| 402 | vmfile = shmem_file_setup(name, asma->size, vma->vm_flags); |
Viresh Kumar | 7f44cb0 | 2015-07-31 14:08:30 +0530 | [diff] [blame] | 403 | if (IS_ERR(vmfile)) { |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 404 | ret = PTR_ERR(vmfile); |
| 405 | goto out; |
| 406 | } |
zhangshuxiao | b8b8c5a | 2017-03-08 16:53:24 +0800 | [diff] [blame] | 407 | vmfile->f_mode |= FMODE_LSEEK; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 408 | asma->file = vmfile; |
| 409 | } |
| 410 | get_file(asma->file); |
| 411 | |
John Stultz | 6f19367 | 2011-12-15 18:51:04 -0800 | [diff] [blame] | 412 | if (vma->vm_flags & VM_SHARED) |
| 413 | shmem_set_file(vma, asma->file); |
| 414 | else { |
| 415 | if (vma->vm_file) |
| 416 | fput(vma->vm_file); |
| 417 | vma->vm_file = asma->file; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 418 | } |
| 419 | |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 420 | out: |
| 421 | mutex_unlock(&ashmem_mutex); |
| 422 | return ret; |
| 423 | } |
| 424 | |
| 425 | /* |
Johannes Weiner | 6b4f779 | 2014-12-12 16:56:13 -0800 | [diff] [blame] | 426 | * ashmem_shrink - our cache shrinker, called from mm/vmscan.c |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 427 | * |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 428 | * 'nr_to_scan' is the number of objects to scan for freeing. |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 429 | * |
| 430 | * 'gfp_mask' is the mask of the allocation that got us into this mess. |
| 431 | * |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 432 | * Return value is the number of objects freed or -1 if we cannot |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 433 | * proceed without risk of deadlock (due to gfp_mask). |
| 434 | * |
| 435 | * We approximate LRU via least-recently-unpinned, jettisoning unpinned partial |
| 436 | * chunks of ashmem regions LRU-wise one-at-a-time until we hit 'nr_to_scan' |
| 437 | * pages freed. |
| 438 | */ |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 439 | static unsigned long |
| 440 | ashmem_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 441 | { |
| 442 | struct ashmem_range *range, *next; |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 443 | unsigned long freed = 0; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 444 | |
| 445 | /* We might recurse into filesystem code, so bail out if necessary */ |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 446 | if (!(sc->gfp_mask & __GFP_FS)) |
| 447 | return SHRINK_STOP; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 448 | |
Laura Abbott | 18e7705 | 2016-01-29 22:07:30 -0800 | [diff] [blame] | 449 | if (!mutex_trylock(&ashmem_mutex)) |
| 450 | return -1; |
| 451 | |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 452 | list_for_each_entry_safe(range, next, &ashmem_lru_list, lru) { |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 453 | loff_t start = range->pgstart * PAGE_SIZE; |
Hugh Dickins | 3f31d07 | 2012-05-29 15:06:40 -0700 | [diff] [blame] | 454 | loff_t end = (range->pgend + 1) * PAGE_SIZE; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 455 | |
Tobias Lindskog | b3505d2 | 2015-02-09 08:10:39 +0100 | [diff] [blame] | 456 | range->asma->file->f_op->fallocate(range->asma->file, |
| 457 | FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, |
| 458 | start, end - start); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 459 | range->purged = ASHMEM_WAS_PURGED; |
| 460 | lru_del(range); |
| 461 | |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 462 | freed += range_size(range); |
| 463 | if (--sc->nr_to_scan <= 0) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 464 | break; |
| 465 | } |
| 466 | mutex_unlock(&ashmem_mutex); |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 467 | return freed; |
| 468 | } |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 469 | |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 470 | static unsigned long |
| 471 | ashmem_shrink_count(struct shrinker *shrink, struct shrink_control *sc) |
| 472 | { |
| 473 | /* |
| 474 | * note that lru_count is count of pages on the lru, not a count of |
| 475 | * objects on the list. This means the scan function needs to return the |
| 476 | * number of pages freed, not the number of objects scanned. |
| 477 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 478 | return lru_count; |
| 479 | } |
| 480 | |
| 481 | static struct shrinker ashmem_shrinker = { |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 482 | .count_objects = ashmem_shrink_count, |
| 483 | .scan_objects = ashmem_shrink_scan, |
| 484 | /* |
| 485 | * XXX (dchinner): I wish people would comment on why they need on |
| 486 | * significant changes to the default value here |
| 487 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 488 | .seeks = DEFAULT_SEEKS * 4, |
| 489 | }; |
| 490 | |
| 491 | static int set_prot_mask(struct ashmem_area *asma, unsigned long prot) |
| 492 | { |
| 493 | int ret = 0; |
| 494 | |
| 495 | mutex_lock(&ashmem_mutex); |
| 496 | |
| 497 | /* the user can only remove, not add, protection bits */ |
| 498 | if (unlikely((asma->prot_mask & prot) != prot)) { |
| 499 | ret = -EINVAL; |
| 500 | goto out; |
| 501 | } |
| 502 | |
| 503 | /* does the application expect PROT_READ to imply PROT_EXEC? */ |
| 504 | if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) |
| 505 | prot |= PROT_EXEC; |
| 506 | |
| 507 | asma->prot_mask = prot; |
| 508 | |
| 509 | out: |
| 510 | mutex_unlock(&ashmem_mutex); |
| 511 | return ret; |
| 512 | } |
| 513 | |
| 514 | static int set_name(struct ashmem_area *asma, void __user *name) |
| 515 | { |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 516 | int len; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 517 | int ret = 0; |
Shankar Brahadeeswaran | e5834d6 | 2013-02-20 23:41:26 +0530 | [diff] [blame] | 518 | char local_name[ASHMEM_NAME_LEN]; |
| 519 | |
| 520 | /* |
| 521 | * Holding the ashmem_mutex while doing a copy_from_user might cause |
| 522 | * an data abort which would try to access mmap_sem. If another |
| 523 | * thread has invoked ashmem_mmap then it will be holding the |
| 524 | * semaphore and will be waiting for ashmem_mutex, there by leading to |
| 525 | * deadlock. We'll release the mutex and take the name to a local |
| 526 | * variable that does not need protection and later copy the local |
| 527 | * variable to the structure member with lock held. |
| 528 | */ |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 529 | len = strncpy_from_user(local_name, name, ASHMEM_NAME_LEN); |
| 530 | if (len < 0) |
| 531 | return len; |
| 532 | if (len == ASHMEM_NAME_LEN) |
| 533 | local_name[ASHMEM_NAME_LEN - 1] = '\0'; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 534 | mutex_lock(&ashmem_mutex); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 535 | /* cannot change an existing mapping's name */ |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 536 | if (unlikely(asma->file)) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 537 | ret = -EINVAL; |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 538 | else |
| 539 | strcpy(asma->name + ASHMEM_NAME_PREFIX_LEN, local_name); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 540 | |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 541 | mutex_unlock(&ashmem_mutex); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 542 | return ret; |
| 543 | } |
| 544 | |
| 545 | static int get_name(struct ashmem_area *asma, void __user *name) |
| 546 | { |
| 547 | int ret = 0; |
Shankar Brahadeeswaran | e5834d6 | 2013-02-20 23:41:26 +0530 | [diff] [blame] | 548 | size_t len; |
| 549 | /* |
| 550 | * Have a local variable to which we'll copy the content |
| 551 | * from asma with the lock held. Later we can copy this to the user |
| 552 | * space safely without holding any locks. So even if we proceed to |
| 553 | * wait for mmap_sem, it won't lead to deadlock. |
| 554 | */ |
| 555 | char local_name[ASHMEM_NAME_LEN]; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 556 | |
| 557 | mutex_lock(&ashmem_mutex); |
| 558 | if (asma->name[ASHMEM_NAME_PREFIX_LEN] != '\0') { |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 559 | /* |
| 560 | * Copying only `len', instead of ASHMEM_NAME_LEN, bytes |
| 561 | * prevents us from revealing one user's stack to another. |
| 562 | */ |
| 563 | len = strlen(asma->name + ASHMEM_NAME_PREFIX_LEN) + 1; |
Shankar Brahadeeswaran | e5834d6 | 2013-02-20 23:41:26 +0530 | [diff] [blame] | 564 | memcpy(local_name, asma->name + ASHMEM_NAME_PREFIX_LEN, len); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 565 | } else { |
Shankar Brahadeeswaran | e5834d6 | 2013-02-20 23:41:26 +0530 | [diff] [blame] | 566 | len = sizeof(ASHMEM_NAME_DEF); |
| 567 | memcpy(local_name, ASHMEM_NAME_DEF, len); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 568 | } |
| 569 | mutex_unlock(&ashmem_mutex); |
| 570 | |
Shankar Brahadeeswaran | e5834d6 | 2013-02-20 23:41:26 +0530 | [diff] [blame] | 571 | /* |
| 572 | * Now we are just copying from the stack variable to userland |
| 573 | * No lock held |
| 574 | */ |
| 575 | if (unlikely(copy_to_user(name, local_name, len))) |
| 576 | ret = -EFAULT; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 577 | return ret; |
| 578 | } |
| 579 | |
| 580 | /* |
| 581 | * ashmem_pin - pin the given ashmem region, returning whether it was |
| 582 | * previously purged (ASHMEM_WAS_PURGED) or not (ASHMEM_NOT_PURGED). |
| 583 | * |
| 584 | * Caller must hold ashmem_mutex. |
| 585 | */ |
| 586 | static int ashmem_pin(struct ashmem_area *asma, size_t pgstart, size_t pgend) |
| 587 | { |
| 588 | struct ashmem_range *range, *next; |
| 589 | int ret = ASHMEM_NOT_PURGED; |
| 590 | |
| 591 | list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned) { |
| 592 | /* moved past last applicable page; we can short circuit */ |
| 593 | if (range_before_page(range, pgstart)) |
| 594 | break; |
| 595 | |
| 596 | /* |
| 597 | * The user can ask us to pin pages that span multiple ranges, |
| 598 | * or to pin pages that aren't even unpinned, so this is messy. |
| 599 | * |
| 600 | * Four cases: |
| 601 | * 1. The requested range subsumes an existing range, so we |
| 602 | * just remove the entire matching range. |
| 603 | * 2. The requested range overlaps the start of an existing |
| 604 | * range, so we just update that range. |
| 605 | * 3. The requested range overlaps the end of an existing |
| 606 | * range, so we just update that range. |
| 607 | * 4. The requested range punches a hole in an existing range, |
| 608 | * so we have to update one side of the range and then |
| 609 | * create a new range for the other side. |
| 610 | */ |
| 611 | if (page_range_in_range(range, pgstart, pgend)) { |
| 612 | ret |= range->purged; |
| 613 | |
| 614 | /* Case #1: Easy. Just nuke the whole thing. */ |
| 615 | if (page_range_subsumes_range(range, pgstart, pgend)) { |
| 616 | range_del(range); |
| 617 | continue; |
| 618 | } |
| 619 | |
| 620 | /* Case #2: We overlap from the start, so adjust it */ |
| 621 | if (range->pgstart >= pgstart) { |
| 622 | range_shrink(range, pgend + 1, range->pgend); |
| 623 | continue; |
| 624 | } |
| 625 | |
| 626 | /* Case #3: We overlap from the rear, so adjust it */ |
| 627 | if (range->pgend <= pgend) { |
Peng Sun | d2e4f68 | 2015-08-27 15:41:05 +0800 | [diff] [blame] | 628 | range_shrink(range, range->pgstart, |
| 629 | pgstart - 1); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 630 | continue; |
| 631 | } |
| 632 | |
| 633 | /* |
| 634 | * Case #4: We eat a chunk out of the middle. A bit |
| 635 | * more complicated, we allocate a new range for the |
| 636 | * second half and adjust the first chunk's endpoint. |
| 637 | */ |
| 638 | range_alloc(asma, range, range->purged, |
| 639 | pgend + 1, range->pgend); |
| 640 | range_shrink(range, range->pgstart, pgstart - 1); |
| 641 | break; |
| 642 | } |
| 643 | } |
| 644 | |
| 645 | return ret; |
| 646 | } |
| 647 | |
| 648 | /* |
| 649 | * ashmem_unpin - unpin the given range of pages. Returns zero on success. |
| 650 | * |
| 651 | * Caller must hold ashmem_mutex. |
| 652 | */ |
| 653 | static int ashmem_unpin(struct ashmem_area *asma, size_t pgstart, size_t pgend) |
| 654 | { |
| 655 | struct ashmem_range *range, *next; |
| 656 | unsigned int purged = ASHMEM_NOT_PURGED; |
| 657 | |
| 658 | restart: |
| 659 | list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned) { |
| 660 | /* short circuit: this is our insertion point */ |
| 661 | if (range_before_page(range, pgstart)) |
| 662 | break; |
| 663 | |
| 664 | /* |
| 665 | * The user can ask us to unpin pages that are already entirely |
| 666 | * or partially pinned. We handle those two cases here. |
| 667 | */ |
| 668 | if (page_range_subsumed_by_range(range, pgstart, pgend)) |
| 669 | return 0; |
| 670 | if (page_range_in_range(range, pgstart, pgend)) { |
Amitoj Kaur Chawla | 9f1c427 | 2016-02-25 08:18:52 +0530 | [diff] [blame] | 671 | pgstart = min(range->pgstart, pgstart); |
| 672 | pgend = max(range->pgend, pgend); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 673 | purged |= range->purged; |
| 674 | range_del(range); |
| 675 | goto restart; |
| 676 | } |
| 677 | } |
| 678 | |
| 679 | return range_alloc(asma, range, purged, pgstart, pgend); |
| 680 | } |
| 681 | |
| 682 | /* |
| 683 | * ashmem_get_pin_status - Returns ASHMEM_IS_UNPINNED if _any_ pages in the |
| 684 | * given interval are unpinned and ASHMEM_IS_PINNED otherwise. |
| 685 | * |
| 686 | * Caller must hold ashmem_mutex. |
| 687 | */ |
| 688 | static int ashmem_get_pin_status(struct ashmem_area *asma, size_t pgstart, |
| 689 | size_t pgend) |
| 690 | { |
| 691 | struct ashmem_range *range; |
| 692 | int ret = ASHMEM_IS_PINNED; |
| 693 | |
| 694 | list_for_each_entry(range, &asma->unpinned_list, unpinned) { |
| 695 | if (range_before_page(range, pgstart)) |
| 696 | break; |
| 697 | if (page_range_in_range(range, pgstart, pgend)) { |
| 698 | ret = ASHMEM_IS_UNPINNED; |
| 699 | break; |
| 700 | } |
| 701 | } |
| 702 | |
| 703 | return ret; |
| 704 | } |
| 705 | |
| 706 | static int ashmem_pin_unpin(struct ashmem_area *asma, unsigned long cmd, |
| 707 | void __user *p) |
| 708 | { |
| 709 | struct ashmem_pin pin; |
| 710 | size_t pgstart, pgend; |
| 711 | int ret = -EINVAL; |
| 712 | |
Yisheng Xie | 71df7bb | 2018-02-28 14:59:22 +0800 | [diff] [blame] | 713 | if (unlikely(copy_from_user(&pin, p, sizeof(pin)))) |
| 714 | return -EFAULT; |
| 715 | |
Ben Hutchings | 2dfe49d | 2018-02-04 02:06:27 +0000 | [diff] [blame] | 716 | mutex_lock(&ashmem_mutex); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 717 | |
Ben Hutchings | 2dfe49d | 2018-02-04 02:06:27 +0000 | [diff] [blame] | 718 | if (unlikely(!asma->file)) |
| 719 | goto out_unlock; |
| 720 | |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 721 | /* per custom, you can pass zero for len to mean "everything onward" */ |
| 722 | if (!pin.len) |
| 723 | pin.len = PAGE_ALIGN(asma->size) - pin.offset; |
| 724 | |
| 725 | if (unlikely((pin.offset | pin.len) & ~PAGE_MASK)) |
Ben Hutchings | 2dfe49d | 2018-02-04 02:06:27 +0000 | [diff] [blame] | 726 | goto out_unlock; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 727 | |
Peng Sun | b8d3bfa | 2015-08-27 15:41:06 +0800 | [diff] [blame] | 728 | if (unlikely(((__u32)-1) - pin.offset < pin.len)) |
Ben Hutchings | 2dfe49d | 2018-02-04 02:06:27 +0000 | [diff] [blame] | 729 | goto out_unlock; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 730 | |
| 731 | if (unlikely(PAGE_ALIGN(asma->size) < pin.offset + pin.len)) |
Ben Hutchings | 2dfe49d | 2018-02-04 02:06:27 +0000 | [diff] [blame] | 732 | goto out_unlock; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 733 | |
| 734 | pgstart = pin.offset / PAGE_SIZE; |
| 735 | pgend = pgstart + (pin.len / PAGE_SIZE) - 1; |
| 736 | |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 737 | switch (cmd) { |
| 738 | case ASHMEM_PIN: |
| 739 | ret = ashmem_pin(asma, pgstart, pgend); |
| 740 | break; |
| 741 | case ASHMEM_UNPIN: |
| 742 | ret = ashmem_unpin(asma, pgstart, pgend); |
| 743 | break; |
| 744 | case ASHMEM_GET_PIN_STATUS: |
| 745 | ret = ashmem_get_pin_status(asma, pgstart, pgend); |
| 746 | break; |
| 747 | } |
| 748 | |
Ben Hutchings | 2dfe49d | 2018-02-04 02:06:27 +0000 | [diff] [blame] | 749 | out_unlock: |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 750 | mutex_unlock(&ashmem_mutex); |
| 751 | |
| 752 | return ret; |
| 753 | } |
| 754 | |
| 755 | static long ashmem_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| 756 | { |
| 757 | struct ashmem_area *asma = file->private_data; |
| 758 | long ret = -ENOTTY; |
| 759 | |
| 760 | switch (cmd) { |
| 761 | case ASHMEM_SET_NAME: |
Fabian Holler | 1703ca9 | 2015-01-07 10:39:54 +0100 | [diff] [blame] | 762 | ret = set_name(asma, (void __user *)arg); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 763 | break; |
| 764 | case ASHMEM_GET_NAME: |
Fabian Holler | 1703ca9 | 2015-01-07 10:39:54 +0100 | [diff] [blame] | 765 | ret = get_name(asma, (void __user *)arg); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 766 | break; |
| 767 | case ASHMEM_SET_SIZE: |
| 768 | ret = -EINVAL; |
Viktor Slavkovic | c51d23d | 2018-01-08 10:43:03 -0800 | [diff] [blame] | 769 | mutex_lock(&ashmem_mutex); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 770 | if (!asma->file) { |
| 771 | ret = 0; |
Peng Sun | b8d3bfa | 2015-08-27 15:41:06 +0800 | [diff] [blame] | 772 | asma->size = (size_t)arg; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 773 | } |
Viktor Slavkovic | c51d23d | 2018-01-08 10:43:03 -0800 | [diff] [blame] | 774 | mutex_unlock(&ashmem_mutex); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 775 | break; |
| 776 | case ASHMEM_GET_SIZE: |
| 777 | ret = asma->size; |
| 778 | break; |
| 779 | case ASHMEM_SET_PROT_MASK: |
| 780 | ret = set_prot_mask(asma, arg); |
| 781 | break; |
| 782 | case ASHMEM_GET_PROT_MASK: |
| 783 | ret = asma->prot_mask; |
| 784 | break; |
| 785 | case ASHMEM_PIN: |
| 786 | case ASHMEM_UNPIN: |
| 787 | case ASHMEM_GET_PIN_STATUS: |
Fabian Holler | 1703ca9 | 2015-01-07 10:39:54 +0100 | [diff] [blame] | 788 | ret = ashmem_pin_unpin(asma, cmd, (void __user *)arg); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 789 | break; |
| 790 | case ASHMEM_PURGE_ALL_CACHES: |
| 791 | ret = -EPERM; |
| 792 | if (capable(CAP_SYS_ADMIN)) { |
Colin Cross | 33e8fc4 | 2011-12-20 16:49:53 -0800 | [diff] [blame] | 793 | struct shrink_control sc = { |
| 794 | .gfp_mask = GFP_KERNEL, |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 795 | .nr_to_scan = LONG_MAX, |
Colin Cross | 33e8fc4 | 2011-12-20 16:49:53 -0800 | [diff] [blame] | 796 | }; |
John Stultz | 5957324 | 2013-10-21 09:58:07 -0700 | [diff] [blame] | 797 | ret = ashmem_shrink_count(&ashmem_shrinker, &sc); |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 798 | ashmem_shrink_scan(&ashmem_shrinker, &sc); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 799 | } |
| 800 | break; |
| 801 | } |
| 802 | |
| 803 | return ret; |
| 804 | } |
| 805 | |
Serban Constantinescu | e9f5b81 | 2013-03-05 15:27:38 +0000 | [diff] [blame] | 806 | /* support of 32bit userspace on 64bit platforms */ |
| 807 | #ifdef CONFIG_COMPAT |
Marlies Ruck | 017ca3b | 2013-05-10 16:26:30 -0400 | [diff] [blame] | 808 | static long compat_ashmem_ioctl(struct file *file, unsigned int cmd, |
| 809 | unsigned long arg) |
Serban Constantinescu | e9f5b81 | 2013-03-05 15:27:38 +0000 | [diff] [blame] | 810 | { |
Serban Constantinescu | e9f5b81 | 2013-03-05 15:27:38 +0000 | [diff] [blame] | 811 | switch (cmd) { |
| 812 | case COMPAT_ASHMEM_SET_SIZE: |
| 813 | cmd = ASHMEM_SET_SIZE; |
| 814 | break; |
| 815 | case COMPAT_ASHMEM_SET_PROT_MASK: |
| 816 | cmd = ASHMEM_SET_PROT_MASK; |
| 817 | break; |
| 818 | } |
| 819 | return ashmem_ioctl(file, cmd, arg); |
| 820 | } |
| 821 | #endif |
| 822 | |
Tracey Dent | aa5af97 | 2012-01-22 21:28:44 -0500 | [diff] [blame] | 823 | static const struct file_operations ashmem_fops = { |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 824 | .owner = THIS_MODULE, |
| 825 | .open = ashmem_open, |
| 826 | .release = ashmem_release, |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 827 | .read = ashmem_read, |
| 828 | .llseek = ashmem_llseek, |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 829 | .mmap = ashmem_mmap, |
| 830 | .unlocked_ioctl = ashmem_ioctl, |
Serban Constantinescu | e9f5b81 | 2013-03-05 15:27:38 +0000 | [diff] [blame] | 831 | #ifdef CONFIG_COMPAT |
| 832 | .compat_ioctl = compat_ashmem_ioctl, |
| 833 | #endif |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 834 | }; |
| 835 | |
| 836 | static struct miscdevice ashmem_misc = { |
| 837 | .minor = MISC_DYNAMIC_MINOR, |
| 838 | .name = "ashmem", |
| 839 | .fops = &ashmem_fops, |
| 840 | }; |
| 841 | |
| 842 | static int __init ashmem_init(void) |
| 843 | { |
Wenwei Tao | a2df4e3 | 2015-12-09 00:15:52 +0800 | [diff] [blame] | 844 | int ret = -ENOMEM; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 845 | |
| 846 | ashmem_area_cachep = kmem_cache_create("ashmem_area_cache", |
Peng Sun | 7048c1f | 2015-08-27 15:41:07 +0800 | [diff] [blame] | 847 | sizeof(struct ashmem_area), |
| 848 | 0, 0, NULL); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 849 | if (unlikely(!ashmem_area_cachep)) { |
Sachin Kamat | c810a39 | 2012-06-05 16:40:10 +0530 | [diff] [blame] | 850 | pr_err("failed to create slab cache\n"); |
Wenwei Tao | a2df4e3 | 2015-12-09 00:15:52 +0800 | [diff] [blame] | 851 | goto out; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 852 | } |
| 853 | |
| 854 | ashmem_range_cachep = kmem_cache_create("ashmem_range_cache", |
Peng Sun | 7048c1f | 2015-08-27 15:41:07 +0800 | [diff] [blame] | 855 | sizeof(struct ashmem_range), |
| 856 | 0, 0, NULL); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 857 | if (unlikely(!ashmem_range_cachep)) { |
Sachin Kamat | c810a39 | 2012-06-05 16:40:10 +0530 | [diff] [blame] | 858 | pr_err("failed to create slab cache\n"); |
Wenwei Tao | a2df4e3 | 2015-12-09 00:15:52 +0800 | [diff] [blame] | 859 | goto out_free1; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 860 | } |
| 861 | |
| 862 | ret = misc_register(&ashmem_misc); |
| 863 | if (unlikely(ret)) { |
Sachin Kamat | c810a39 | 2012-06-05 16:40:10 +0530 | [diff] [blame] | 864 | pr_err("failed to register misc device!\n"); |
Wenwei Tao | a2df4e3 | 2015-12-09 00:15:52 +0800 | [diff] [blame] | 865 | goto out_free2; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 866 | } |
| 867 | |
| 868 | register_shrinker(&ashmem_shrinker); |
| 869 | |
Sachin Kamat | c810a39 | 2012-06-05 16:40:10 +0530 | [diff] [blame] | 870 | pr_info("initialized\n"); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 871 | |
| 872 | return 0; |
Wenwei Tao | a2df4e3 | 2015-12-09 00:15:52 +0800 | [diff] [blame] | 873 | |
| 874 | out_free2: |
| 875 | kmem_cache_destroy(ashmem_range_cachep); |
| 876 | out_free1: |
| 877 | kmem_cache_destroy(ashmem_area_cachep); |
| 878 | out: |
| 879 | return ret; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 880 | } |
Paul Gortmaker | 12950595 | 2015-10-11 15:47:28 -0400 | [diff] [blame] | 881 | device_initcall(ashmem_init); |