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 static int firmware_map_add_entry(u64 start, u64 end, 149 const char *type, 150 struct firmware_map_entry *entry) 151 { 152 BUG_ON(start > end); 153 154 entry->start = start; 155 entry->end = end - 1; 156 entry->type = type; 157 INIT_LIST_HEAD(&entry->list); 158 kobject_init(&entry->kobj, &memmap_ktype); 159 160 spin_lock(&map_entries_lock); 161 list_add_tail(&entry->list, &map_entries); 162 spin_unlock(&map_entries_lock); 163 164 return 0; 165 } 166 167 /** 168 * firmware_map_remove_entry() - Does the real work to remove a firmware 169 * memmap entry. 170 * @entry: removed entry. 171 * 172 * The caller must hold map_entries_lock, and release it properly. 173 **/ 174 static inline void firmware_map_remove_entry(struct firmware_map_entry *entry) 175 { 176 list_del(&entry->list); 177 } 178 179 /* 180 * Add memmap entry on sysfs 181 */ 182 static int add_sysfs_fw_map_entry(struct firmware_map_entry *entry) 183 { 184 static int map_entries_nr; 185 static struct kset *mmap_kset; 186 187 if (!mmap_kset) { 188 mmap_kset = kset_create_and_add("memmap", NULL, firmware_kobj); 189 if (!mmap_kset) 190 return -ENOMEM; 191 } 192 193 entry->kobj.kset = mmap_kset; 194 if (kobject_add(&entry->kobj, NULL, "%d", map_entries_nr++)) 195 kobject_put(&entry->kobj); 196 197 return 0; 198 } 199 200 /* 201 * Remove memmap entry on sysfs 202 */ 203 static inline void remove_sysfs_fw_map_entry(struct firmware_map_entry *entry) 204 { 205 kobject_put(&entry->kobj); 206 } 207 208 /* 209 * firmware_map_find_entry_in_list() - Search memmap entry in a given list. 210 * @start: Start of the memory range. 211 * @end: End of the memory range (exclusive). 212 * @type: Type of the memory range. 213 * @list: In which to find the entry. 214 * 215 * This function is to find the memmap entey of a given memory range in a 216 * given list. The caller must hold map_entries_lock, and must not release 217 * the lock until the processing of the returned entry has completed. 218 * 219 * Return: Pointer to the entry to be found on success, or NULL on failure. 220 */ 221 static struct firmware_map_entry * __meminit 222 firmware_map_find_entry_in_list(u64 start, u64 end, const char *type, 223 struct list_head *list) 224 { 225 struct firmware_map_entry *entry; 226 227 list_for_each_entry(entry, list, list) 228 if ((entry->start == start) && (entry->end == end) && 229 (!strcmp(entry->type, type))) { 230 return entry; 231 } 232 233 return NULL; 234 } 235 236 /* 237 * firmware_map_find_entry() - Search memmap entry in map_entries. 238 * @start: Start of the memory range. 239 * @end: End of the memory range (exclusive). 240 * @type: Type of the memory range. 241 * 242 * This function is to find the memmap entey of a given memory range. 243 * The caller must hold map_entries_lock, and must not release the lock 244 * until the processing of the returned entry has completed. 245 * 246 * Return: Pointer to the entry to be found on success, or NULL on failure. 247 */ 248 static struct firmware_map_entry * __meminit 249 firmware_map_find_entry(u64 start, u64 end, const char *type) 250 { 251 return firmware_map_find_entry_in_list(start, end, type, &map_entries); 252 } 253 254 /* 255 * firmware_map_find_entry_bootmem() - Search memmap entry in map_entries_bootmem. 256 * @start: Start of the memory range. 257 * @end: End of the memory range (exclusive). 258 * @type: Type of the memory range. 259 * 260 * This function is similar to firmware_map_find_entry except that it find the 261 * given entry in map_entries_bootmem. 262 * 263 * Return: Pointer to the entry to be found on success, or NULL on failure. 264 */ 265 static struct firmware_map_entry * __meminit 266 firmware_map_find_entry_bootmem(u64 start, u64 end, const char *type) 267 { 268 return firmware_map_find_entry_in_list(start, end, type, 269 &map_entries_bootmem); 270 } 271 272 /** 273 * firmware_map_add_hotplug() - Adds a firmware mapping entry when we do 274 * memory hotplug. 275 * @start: Start of the memory range. 276 * @end: End of the memory range (exclusive) 277 * @type: Type of the memory range. 278 * 279 * Adds a firmware mapping entry. This function is for memory hotplug, it is 280 * similar to function firmware_map_add_early(). The only difference is that 281 * it will create the syfs entry dynamically. 282 * 283 * Returns 0 on success, or -ENOMEM if no memory could be allocated. 284 **/ 285 int __meminit firmware_map_add_hotplug(u64 start, u64 end, const char *type) 286 { 287 struct firmware_map_entry *entry; 288 289 entry = firmware_map_find_entry_bootmem(start, end, type); 290 if (!entry) { 291 entry = kzalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC); 292 if (!entry) 293 return -ENOMEM; 294 } else { 295 /* Reuse storage allocated by bootmem. */ 296 spin_lock(&map_entries_bootmem_lock); 297 list_del(&entry->list); 298 spin_unlock(&map_entries_bootmem_lock); 299 300 memset(entry, 0, sizeof(*entry)); 301 } 302 303 firmware_map_add_entry(start, end, type, entry); 304 /* create the memmap entry */ 305 add_sysfs_fw_map_entry(entry); 306 307 return 0; 308 } 309 310 /** 311 * firmware_map_add_early() - Adds a firmware mapping entry. 312 * @start: Start of the memory range. 313 * @end: End of the memory range. 314 * @type: Type of the memory range. 315 * 316 * Adds a firmware mapping entry. This function uses the bootmem allocator 317 * for memory allocation. 318 * 319 * That function must be called before late_initcall. 320 * 321 * Returns 0 on success, or -ENOMEM if no memory could be allocated. 322 **/ 323 int __init firmware_map_add_early(u64 start, u64 end, const char *type) 324 { 325 struct firmware_map_entry *entry; 326 327 entry = alloc_bootmem(sizeof(struct firmware_map_entry)); 328 if (WARN_ON(!entry)) 329 return -ENOMEM; 330 331 return firmware_map_add_entry(start, end, type, entry); 332 } 333 334 /** 335 * firmware_map_remove() - remove a firmware mapping entry 336 * @start: Start of the memory range. 337 * @end: End of the memory range. 338 * @type: Type of the memory range. 339 * 340 * removes a firmware mapping entry. 341 * 342 * Returns 0 on success, or -EINVAL if no entry. 343 **/ 344 int __meminit firmware_map_remove(u64 start, u64 end, const char *type) 345 { 346 struct firmware_map_entry *entry; 347 348 spin_lock(&map_entries_lock); 349 entry = firmware_map_find_entry(start, end - 1, type); 350 if (!entry) { 351 spin_unlock(&map_entries_lock); 352 return -EINVAL; 353 } 354 355 firmware_map_remove_entry(entry); 356 spin_unlock(&map_entries_lock); 357 358 /* remove the memmap entry */ 359 remove_sysfs_fw_map_entry(entry); 360 361 return 0; 362 } 363 364 /* 365 * Sysfs functions ------------------------------------------------------------- 366 */ 367 368 static ssize_t start_show(struct firmware_map_entry *entry, char *buf) 369 { 370 return snprintf(buf, PAGE_SIZE, "0x%llx\n", 371 (unsigned long long)entry->start); 372 } 373 374 static ssize_t end_show(struct firmware_map_entry *entry, char *buf) 375 { 376 return snprintf(buf, PAGE_SIZE, "0x%llx\n", 377 (unsigned long long)entry->end); 378 } 379 380 static ssize_t type_show(struct firmware_map_entry *entry, char *buf) 381 { 382 return snprintf(buf, PAGE_SIZE, "%s\n", entry->type); 383 } 384 385 static inline struct memmap_attribute *to_memmap_attr(struct attribute *attr) 386 { 387 return container_of(attr, struct memmap_attribute, attr); 388 } 389 390 static ssize_t memmap_attr_show(struct kobject *kobj, 391 struct attribute *attr, char *buf) 392 { 393 struct firmware_map_entry *entry = to_memmap_entry(kobj); 394 struct memmap_attribute *memmap_attr = to_memmap_attr(attr); 395 396 return memmap_attr->show(entry, buf); 397 } 398 399 /* 400 * Initialises stuff and adds the entries in the map_entries list to 401 * sysfs. Important is that firmware_map_add() and firmware_map_add_early() 402 * must be called before late_initcall. That's just because that function 403 * is called as late_initcall() function, which means that if you call 404 * firmware_map_add() or firmware_map_add_early() afterwards, the entries 405 * are not added to sysfs. 406 */ 407 static int __init firmware_memmap_init(void) 408 { 409 struct firmware_map_entry *entry; 410 411 list_for_each_entry(entry, &map_entries, list) 412 add_sysfs_fw_map_entry(entry); 413 414 return 0; 415 } 416 late_initcall(firmware_memmap_init); 417 418