1 /* 2 * linux/drivers/firmware/memmap.c 3 * Copyright (C) 2008 SUSE LINUX Products GmbH 4 * by Bernhard Walle <bernhard.walle@gmx.de> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License v2.0 as published by 8 * the Free Software Foundation 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 */ 16 17 #include <linux/string.h> 18 #include <linux/firmware-map.h> 19 #include <linux/kernel.h> 20 #include <linux/module.h> 21 #include <linux/types.h> 22 #include <linux/bootmem.h> 23 #include <linux/slab.h> 24 #include <linux/mm.h> 25 26 /* 27 * Data types ------------------------------------------------------------------ 28 */ 29 30 /* 31 * Firmware map entry. Because firmware memory maps are flat and not 32 * hierarchical, it's ok to organise them in a linked list. No parent 33 * information is necessary as for the resource tree. 34 */ 35 struct firmware_map_entry { 36 /* 37 * start and end must be u64 rather than resource_size_t, because e820 38 * resources can lie at addresses above 4G. 39 */ 40 u64 start; /* start of the memory range */ 41 u64 end; /* end of the memory range (incl.) */ 42 const char *type; /* type of the memory range */ 43 struct list_head list; /* entry for the linked list */ 44 struct kobject kobj; /* kobject for each entry */ 45 }; 46 47 /* 48 * Forward declarations -------------------------------------------------------- 49 */ 50 static ssize_t memmap_attr_show(struct kobject *kobj, 51 struct attribute *attr, char *buf); 52 static ssize_t start_show(struct firmware_map_entry *entry, char *buf); 53 static ssize_t end_show(struct firmware_map_entry *entry, char *buf); 54 static ssize_t type_show(struct firmware_map_entry *entry, char *buf); 55 56 static struct firmware_map_entry * __meminit 57 firmware_map_find_entry(u64 start, u64 end, const char *type); 58 59 /* 60 * Static data ----------------------------------------------------------------- 61 */ 62 63 struct memmap_attribute { 64 struct attribute attr; 65 ssize_t (*show)(struct firmware_map_entry *entry, char *buf); 66 }; 67 68 static struct memmap_attribute memmap_start_attr = __ATTR_RO(start); 69 static struct memmap_attribute memmap_end_attr = __ATTR_RO(end); 70 static struct memmap_attribute memmap_type_attr = __ATTR_RO(type); 71 72 /* 73 * These are default attributes that are added for every memmap entry. 74 */ 75 static struct attribute *def_attrs[] = { 76 &memmap_start_attr.attr, 77 &memmap_end_attr.attr, 78 &memmap_type_attr.attr, 79 NULL 80 }; 81 82 static const struct sysfs_ops memmap_attr_ops = { 83 .show = memmap_attr_show, 84 }; 85 86 /* Firmware memory map entries. */ 87 static LIST_HEAD(map_entries); 88 static DEFINE_SPINLOCK(map_entries_lock); 89 90 /* 91 * For memory hotplug, there is no way to free memory map entries allocated 92 * by boot mem after the system is up. So when we hot-remove memory whose 93 * map entry is allocated by bootmem, we need to remember the storage and 94 * reuse it when the memory is hot-added again. 95 */ 96 static LIST_HEAD(map_entries_bootmem); 97 static DEFINE_SPINLOCK(map_entries_bootmem_lock); 98 99 100 static inline struct firmware_map_entry * 101 to_memmap_entry(struct kobject *kobj) 102 { 103 return container_of(kobj, struct firmware_map_entry, kobj); 104 } 105 106 static void __meminit release_firmware_map_entry(struct kobject *kobj) 107 { 108 struct firmware_map_entry *entry = to_memmap_entry(kobj); 109 110 if (PageReserved(virt_to_page(entry))) { 111 /* 112 * Remember the storage allocated by bootmem, and reuse it when 113 * the memory is hot-added again. The entry will be added to 114 * map_entries_bootmem here, and deleted from &map_entries in 115 * firmware_map_remove_entry(). 116 */ 117 spin_lock(&map_entries_bootmem_lock); 118 list_add(&entry->list, &map_entries_bootmem); 119 spin_unlock(&map_entries_bootmem_lock); 120 121 return; 122 } 123 124 kfree(entry); 125 } 126 127 static struct kobj_type __refdata memmap_ktype = { 128 .release = release_firmware_map_entry, 129 .sysfs_ops = &memmap_attr_ops, 130 .default_attrs = def_attrs, 131 }; 132 133 /* 134 * Registration functions ------------------------------------------------------ 135 */ 136 137 /** 138 * firmware_map_add_entry() - Does the real work to add a firmware memmap entry. 139 * @start: Start of the memory range. 140 * @end: End of the memory range (exclusive). 141 * @type: Type of the memory range. 142 * @entry: Pre-allocated (either kmalloc() or bootmem allocator), uninitialised 143 * entry. 144 * 145 * Common implementation of firmware_map_add() and firmware_map_add_early() 146 * which expects a pre-allocated struct firmware_map_entry. 147 * 148 * Return: 0 always 149 */ 150 static int firmware_map_add_entry(u64 start, u64 end, 151 const char *type, 152 struct firmware_map_entry *entry) 153 { 154 BUG_ON(start > end); 155 156 entry->start = start; 157 entry->end = end - 1; 158 entry->type = type; 159 INIT_LIST_HEAD(&entry->list); 160 kobject_init(&entry->kobj, &memmap_ktype); 161 162 spin_lock(&map_entries_lock); 163 list_add_tail(&entry->list, &map_entries); 164 spin_unlock(&map_entries_lock); 165 166 return 0; 167 } 168 169 /** 170 * firmware_map_remove_entry() - Does the real work to remove a firmware 171 * memmap entry. 172 * @entry: removed entry. 173 * 174 * The caller must hold map_entries_lock, and release it properly. 175 */ 176 static inline void firmware_map_remove_entry(struct firmware_map_entry *entry) 177 { 178 list_del(&entry->list); 179 } 180 181 /* 182 * Add memmap entry on sysfs 183 */ 184 static int add_sysfs_fw_map_entry(struct firmware_map_entry *entry) 185 { 186 static int map_entries_nr; 187 static struct kset *mmap_kset; 188 189 if (entry->kobj.state_in_sysfs) 190 return -EEXIST; 191 192 if (!mmap_kset) { 193 mmap_kset = kset_create_and_add("memmap", NULL, firmware_kobj); 194 if (!mmap_kset) 195 return -ENOMEM; 196 } 197 198 entry->kobj.kset = mmap_kset; 199 if (kobject_add(&entry->kobj, NULL, "%d", map_entries_nr++)) 200 kobject_put(&entry->kobj); 201 202 return 0; 203 } 204 205 /* 206 * Remove memmap entry on sysfs 207 */ 208 static inline void remove_sysfs_fw_map_entry(struct firmware_map_entry *entry) 209 { 210 kobject_put(&entry->kobj); 211 } 212 213 /** 214 * firmware_map_find_entry_in_list() - Search memmap entry in a given list. 215 * @start: Start of the memory range. 216 * @end: End of the memory range (exclusive). 217 * @type: Type of the memory range. 218 * @list: In which to find the entry. 219 * 220 * This function is to find the memmap entey of a given memory range in a 221 * given list. The caller must hold map_entries_lock, and must not release 222 * the lock until the processing of the returned entry has completed. 223 * 224 * Return: Pointer to the entry to be found on success, or NULL on failure. 225 */ 226 static struct firmware_map_entry * __meminit 227 firmware_map_find_entry_in_list(u64 start, u64 end, const char *type, 228 struct list_head *list) 229 { 230 struct firmware_map_entry *entry; 231 232 list_for_each_entry(entry, list, list) 233 if ((entry->start == start) && (entry->end == end) && 234 (!strcmp(entry->type, type))) { 235 return entry; 236 } 237 238 return NULL; 239 } 240 241 /** 242 * firmware_map_find_entry() - Search memmap entry in map_entries. 243 * @start: Start of the memory range. 244 * @end: End of the memory range (exclusive). 245 * @type: Type of the memory range. 246 * 247 * This function is to find the memmap entey of a given memory range. 248 * The caller must hold map_entries_lock, and must not release the lock 249 * until the processing of the returned entry has completed. 250 * 251 * Return: Pointer to the entry to be found on success, or NULL on failure. 252 */ 253 static struct firmware_map_entry * __meminit 254 firmware_map_find_entry(u64 start, u64 end, const char *type) 255 { 256 return firmware_map_find_entry_in_list(start, end, type, &map_entries); 257 } 258 259 /** 260 * firmware_map_find_entry_bootmem() - Search memmap entry in map_entries_bootmem. 261 * @start: Start of the memory range. 262 * @end: End of the memory range (exclusive). 263 * @type: Type of the memory range. 264 * 265 * This function is similar to firmware_map_find_entry except that it find the 266 * given entry in map_entries_bootmem. 267 * 268 * Return: Pointer to the entry to be found on success, or NULL on failure. 269 */ 270 static struct firmware_map_entry * __meminit 271 firmware_map_find_entry_bootmem(u64 start, u64 end, const char *type) 272 { 273 return firmware_map_find_entry_in_list(start, end, type, 274 &map_entries_bootmem); 275 } 276 277 /** 278 * firmware_map_add_hotplug() - Adds a firmware mapping entry when we do 279 * memory hotplug. 280 * @start: Start of the memory range. 281 * @end: End of the memory range (exclusive) 282 * @type: Type of the memory range. 283 * 284 * Adds a firmware mapping entry. This function is for memory hotplug, it is 285 * similar to function firmware_map_add_early(). The only difference is that 286 * it will create the syfs entry dynamically. 287 * 288 * Return: 0 on success, or -ENOMEM if no memory could be allocated. 289 */ 290 int __meminit firmware_map_add_hotplug(u64 start, u64 end, const char *type) 291 { 292 struct firmware_map_entry *entry; 293 294 entry = firmware_map_find_entry(start, end - 1, type); 295 if (entry) 296 return 0; 297 298 entry = firmware_map_find_entry_bootmem(start, end - 1, type); 299 if (!entry) { 300 entry = kzalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC); 301 if (!entry) 302 return -ENOMEM; 303 } else { 304 /* Reuse storage allocated by bootmem. */ 305 spin_lock(&map_entries_bootmem_lock); 306 list_del(&entry->list); 307 spin_unlock(&map_entries_bootmem_lock); 308 309 memset(entry, 0, sizeof(*entry)); 310 } 311 312 firmware_map_add_entry(start, end, type, entry); 313 /* create the memmap entry */ 314 add_sysfs_fw_map_entry(entry); 315 316 return 0; 317 } 318 319 /** 320 * firmware_map_add_early() - Adds a firmware mapping entry. 321 * @start: Start of the memory range. 322 * @end: End of the memory range. 323 * @type: Type of the memory range. 324 * 325 * Adds a firmware mapping entry. This function uses the bootmem allocator 326 * for memory allocation. 327 * 328 * That function must be called before late_initcall. 329 * 330 * Return: 0 on success, or -ENOMEM if no memory could be allocated. 331 */ 332 int __init firmware_map_add_early(u64 start, u64 end, const char *type) 333 { 334 struct firmware_map_entry *entry; 335 336 entry = memblock_virt_alloc(sizeof(struct firmware_map_entry), 0); 337 if (WARN_ON(!entry)) 338 return -ENOMEM; 339 340 return firmware_map_add_entry(start, end, type, entry); 341 } 342 343 /** 344 * firmware_map_remove() - remove a firmware mapping entry 345 * @start: Start of the memory range. 346 * @end: End of the memory range. 347 * @type: Type of the memory range. 348 * 349 * removes a firmware mapping entry. 350 * 351 * Return: 0 on success, or -EINVAL if no entry. 352 */ 353 int __meminit firmware_map_remove(u64 start, u64 end, const char *type) 354 { 355 struct firmware_map_entry *entry; 356 357 spin_lock(&map_entries_lock); 358 entry = firmware_map_find_entry(start, end - 1, type); 359 if (!entry) { 360 spin_unlock(&map_entries_lock); 361 return -EINVAL; 362 } 363 364 firmware_map_remove_entry(entry); 365 spin_unlock(&map_entries_lock); 366 367 /* remove the memmap entry */ 368 remove_sysfs_fw_map_entry(entry); 369 370 return 0; 371 } 372 373 /* 374 * Sysfs functions ------------------------------------------------------------- 375 */ 376 377 static ssize_t start_show(struct firmware_map_entry *entry, char *buf) 378 { 379 return snprintf(buf, PAGE_SIZE, "0x%llx\n", 380 (unsigned long long)entry->start); 381 } 382 383 static ssize_t end_show(struct firmware_map_entry *entry, char *buf) 384 { 385 return snprintf(buf, PAGE_SIZE, "0x%llx\n", 386 (unsigned long long)entry->end); 387 } 388 389 static ssize_t type_show(struct firmware_map_entry *entry, char *buf) 390 { 391 return snprintf(buf, PAGE_SIZE, "%s\n", entry->type); 392 } 393 394 static inline struct memmap_attribute *to_memmap_attr(struct attribute *attr) 395 { 396 return container_of(attr, struct memmap_attribute, attr); 397 } 398 399 static ssize_t memmap_attr_show(struct kobject *kobj, 400 struct attribute *attr, char *buf) 401 { 402 struct firmware_map_entry *entry = to_memmap_entry(kobj); 403 struct memmap_attribute *memmap_attr = to_memmap_attr(attr); 404 405 return memmap_attr->show(entry, buf); 406 } 407 408 /* 409 * Initialises stuff and adds the entries in the map_entries list to 410 * sysfs. Important is that firmware_map_add() and firmware_map_add_early() 411 * must be called before late_initcall. That's just because that function 412 * is called as late_initcall() function, which means that if you call 413 * firmware_map_add() or firmware_map_add_early() afterwards, the entries 414 * are not added to sysfs. 415 */ 416 static int __init firmware_memmap_init(void) 417 { 418 struct firmware_map_entry *entry; 419 420 list_for_each_entry(entry, &map_entries, list) 421 add_sysfs_fw_map_entry(entry); 422 423 return 0; 424 } 425 late_initcall(firmware_memmap_init); 426 427