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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * linux/drivers/firmware/memmap.c4 * Copyright (C) 2008 SUSE LINUX Products GmbH5 * by Bernhard Walle <bernhard.walle@gmx.de>6 */7 8#include <linux/string.h>9#include <linux/firmware-map.h>10#include <linux/kernel.h>11#include <linux/module.h>12#include <linux/types.h>13#include <linux/memblock.h>14#include <linux/slab.h>15#include <linux/mm.h>16 17/*18 * Data types ------------------------------------------------------------------19 */20 21/*22 * Firmware map entry. Because firmware memory maps are flat and not23 * hierarchical, it's ok to organise them in a linked list. No parent24 * information is necessary as for the resource tree.25 */26struct firmware_map_entry {27 /*28 * start and end must be u64 rather than resource_size_t, because e82029 * resources can lie at addresses above 4G.30 */31 u64 start; /* start of the memory range */32 u64 end; /* end of the memory range (incl.) */33 const char *type; /* type of the memory range */34 struct list_head list; /* entry for the linked list */35 struct kobject kobj; /* kobject for each entry */36};37 38/*39 * Forward declarations --------------------------------------------------------40 */41static ssize_t memmap_attr_show(struct kobject *kobj,42 struct attribute *attr, char *buf);43static ssize_t start_show(struct firmware_map_entry *entry, char *buf);44static ssize_t end_show(struct firmware_map_entry *entry, char *buf);45static ssize_t type_show(struct firmware_map_entry *entry, char *buf);46 47static struct firmware_map_entry * __meminit48firmware_map_find_entry(u64 start, u64 end, const char *type);49 50/*51 * Static data -----------------------------------------------------------------52 */53 54struct memmap_attribute {55 struct attribute attr;56 ssize_t (*show)(struct firmware_map_entry *entry, char *buf);57};58 59static struct memmap_attribute memmap_start_attr = __ATTR_RO(start);60static struct memmap_attribute memmap_end_attr = __ATTR_RO(end);61static struct memmap_attribute memmap_type_attr = __ATTR_RO(type);62 63/*64 * These are default attributes that are added for every memmap entry.65 */66static struct attribute *def_attrs[] = {67 &memmap_start_attr.attr,68 &memmap_end_attr.attr,69 &memmap_type_attr.attr,70 NULL71};72ATTRIBUTE_GROUPS(def);73 74static const struct sysfs_ops memmap_attr_ops = {75 .show = memmap_attr_show,76};77 78/* Firmware memory map entries. */79static LIST_HEAD(map_entries);80static DEFINE_SPINLOCK(map_entries_lock);81 82/*83 * For memory hotplug, there is no way to free memory map entries allocated84 * by boot mem after the system is up. So when we hot-remove memory whose85 * map entry is allocated by bootmem, we need to remember the storage and86 * reuse it when the memory is hot-added again.87 */88static LIST_HEAD(map_entries_bootmem);89static DEFINE_SPINLOCK(map_entries_bootmem_lock);90 91 92static inline struct firmware_map_entry *93to_memmap_entry(struct kobject *kobj)94{95 return container_of(kobj, struct firmware_map_entry, kobj);96}97 98static void __meminit release_firmware_map_entry(struct kobject *kobj)99{100 struct firmware_map_entry *entry = to_memmap_entry(kobj);101 102 if (PageReserved(virt_to_page(entry))) {103 /*104 * Remember the storage allocated by bootmem, and reuse it when105 * the memory is hot-added again. The entry will be added to106 * map_entries_bootmem here, and deleted from &map_entries in107 * firmware_map_remove_entry().108 */109 spin_lock(&map_entries_bootmem_lock);110 list_add(&entry->list, &map_entries_bootmem);111 spin_unlock(&map_entries_bootmem_lock);112 113 return;114 }115 116 kfree(entry);117}118 119static struct kobj_type __refdata memmap_ktype = {120 .release = release_firmware_map_entry,121 .sysfs_ops = &memmap_attr_ops,122 .default_groups = def_groups,123};124 125/*126 * Registration functions ------------------------------------------------------127 */128 129/**130 * firmware_map_add_entry() - Does the real work to add a firmware memmap entry.131 * @start: Start of the memory range.132 * @end: End of the memory range (exclusive).133 * @type: Type of the memory range.134 * @entry: Pre-allocated (either kmalloc() or bootmem allocator), uninitialised135 * entry.136 *137 * Common implementation of firmware_map_add() and firmware_map_add_early()138 * which expects a pre-allocated struct firmware_map_entry.139 *140 * Return: 0 always141 */142static int firmware_map_add_entry(u64 start, u64 end,143 const char *type,144 struct firmware_map_entry *entry)145{146 BUG_ON(start > end);147 148 entry->start = start;149 entry->end = end - 1;150 entry->type = type;151 INIT_LIST_HEAD(&entry->list);152 kobject_init(&entry->kobj, &memmap_ktype);153 154 spin_lock(&map_entries_lock);155 list_add_tail(&entry->list, &map_entries);156 spin_unlock(&map_entries_lock);157 158 return 0;159}160 161/**162 * firmware_map_remove_entry() - Does the real work to remove a firmware163 * memmap entry.164 * @entry: removed entry.165 *166 * The caller must hold map_entries_lock, and release it properly.167 */168static inline void firmware_map_remove_entry(struct firmware_map_entry *entry)169{170 list_del(&entry->list);171}172 173/*174 * Add memmap entry on sysfs175 */176static int add_sysfs_fw_map_entry(struct firmware_map_entry *entry)177{178 static int map_entries_nr;179 static struct kset *mmap_kset;180 181 if (entry->kobj.state_in_sysfs)182 return -EEXIST;183 184 if (!mmap_kset) {185 mmap_kset = kset_create_and_add("memmap", NULL, firmware_kobj);186 if (!mmap_kset)187 return -ENOMEM;188 }189 190 entry->kobj.kset = mmap_kset;191 if (kobject_add(&entry->kobj, NULL, "%d", map_entries_nr++))192 kobject_put(&entry->kobj);193 194 return 0;195}196 197/*198 * Remove memmap entry on sysfs199 */200static inline void remove_sysfs_fw_map_entry(struct firmware_map_entry *entry)201{202 kobject_put(&entry->kobj);203}204 205/**206 * firmware_map_find_entry_in_list() - Search memmap entry in a given list.207 * @start: Start of the memory range.208 * @end: End of the memory range (exclusive).209 * @type: Type of the memory range.210 * @list: In which to find the entry.211 *212 * This function is to find the memmap entey of a given memory range in a213 * given list. The caller must hold map_entries_lock, and must not release214 * the lock until the processing of the returned entry has completed.215 *216 * Return: Pointer to the entry to be found on success, or NULL on failure.217 */218static struct firmware_map_entry * __meminit219firmware_map_find_entry_in_list(u64 start, u64 end, const char *type,220 struct list_head *list)221{222 struct firmware_map_entry *entry;223 224 list_for_each_entry(entry, list, list)225 if ((entry->start == start) && (entry->end == end) &&226 (!strcmp(entry->type, type))) {227 return entry;228 }229 230 return NULL;231}232 233/**234 * firmware_map_find_entry() - Search memmap entry in map_entries.235 * @start: Start of the memory range.236 * @end: End of the memory range (exclusive).237 * @type: Type of the memory range.238 *239 * This function is to find the memmap entey of a given memory range.240 * The caller must hold map_entries_lock, and must not release the lock241 * until the processing of the returned entry has completed.242 *243 * Return: Pointer to the entry to be found on success, or NULL on failure.244 */245static struct firmware_map_entry * __meminit246firmware_map_find_entry(u64 start, u64 end, const char *type)247{248 return firmware_map_find_entry_in_list(start, end, type, &map_entries);249}250 251/**252 * firmware_map_find_entry_bootmem() - Search memmap entry in map_entries_bootmem.253 * @start: Start of the memory range.254 * @end: End of the memory range (exclusive).255 * @type: Type of the memory range.256 *257 * This function is similar to firmware_map_find_entry except that it find the258 * given entry in map_entries_bootmem.259 *260 * Return: Pointer to the entry to be found on success, or NULL on failure.261 */262static struct firmware_map_entry * __meminit263firmware_map_find_entry_bootmem(u64 start, u64 end, const char *type)264{265 return firmware_map_find_entry_in_list(start, end, type,266 &map_entries_bootmem);267}268 269/**270 * firmware_map_add_hotplug() - Adds a firmware mapping entry when we do271 * memory hotplug.272 * @start: Start of the memory range.273 * @end: End of the memory range (exclusive)274 * @type: Type of the memory range.275 *276 * Adds a firmware mapping entry. This function is for memory hotplug, it is277 * similar to function firmware_map_add_early(). The only difference is that278 * it will create the syfs entry dynamically.279 *280 * Return: 0 on success, or -ENOMEM if no memory could be allocated.281 */282int __meminit firmware_map_add_hotplug(u64 start, u64 end, const char *type)283{284 struct firmware_map_entry *entry;285 286 entry = firmware_map_find_entry(start, end - 1, type);287 if (entry)288 return 0;289 290 entry = firmware_map_find_entry_bootmem(start, end - 1, type);291 if (!entry) {292 entry = kzalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC);293 if (!entry)294 return -ENOMEM;295 } else {296 /* Reuse storage allocated by bootmem. */297 spin_lock(&map_entries_bootmem_lock);298 list_del(&entry->list);299 spin_unlock(&map_entries_bootmem_lock);300 301 memset(entry, 0, sizeof(*entry));302 }303 304 firmware_map_add_entry(start, end, type, entry);305 /* create the memmap entry */306 add_sysfs_fw_map_entry(entry);307 308 return 0;309}310 311/**312 * firmware_map_add_early() - Adds a firmware mapping entry.313 * @start: Start of the memory range.314 * @end: End of the memory range.315 * @type: Type of the memory range.316 *317 * Adds a firmware mapping entry. This function uses the bootmem allocator318 * for memory allocation.319 *320 * That function must be called before late_initcall.321 *322 * Return: 0 on success, or -ENOMEM if no memory could be allocated.323 */324int __init firmware_map_add_early(u64 start, u64 end, const char *type)325{326 struct firmware_map_entry *entry;327 328 entry = memblock_alloc(sizeof(struct firmware_map_entry),329 SMP_CACHE_BYTES);330 if (WARN_ON(!entry))331 return -ENOMEM;332 333 return firmware_map_add_entry(start, end, type, entry);334}335 336/**337 * firmware_map_remove() - remove a firmware mapping entry338 * @start: Start of the memory range.339 * @end: End of the memory range.340 * @type: Type of the memory range.341 *342 * removes a firmware mapping entry.343 *344 * Return: 0 on success, or -EINVAL if no entry.345 */346int __meminit firmware_map_remove(u64 start, u64 end, const char *type)347{348 struct firmware_map_entry *entry;349 350 spin_lock(&map_entries_lock);351 entry = firmware_map_find_entry(start, end - 1, type);352 if (!entry) {353 spin_unlock(&map_entries_lock);354 return -EINVAL;355 }356 357 firmware_map_remove_entry(entry);358 spin_unlock(&map_entries_lock);359 360 /* remove the memmap entry */361 remove_sysfs_fw_map_entry(entry);362 363 return 0;364}365 366/*367 * Sysfs functions -------------------------------------------------------------368 */369 370static ssize_t start_show(struct firmware_map_entry *entry, char *buf)371{372 return snprintf(buf, PAGE_SIZE, "0x%llx\n",373 (unsigned long long)entry->start);374}375 376static ssize_t end_show(struct firmware_map_entry *entry, char *buf)377{378 return snprintf(buf, PAGE_SIZE, "0x%llx\n",379 (unsigned long long)entry->end);380}381 382static ssize_t type_show(struct firmware_map_entry *entry, char *buf)383{384 return snprintf(buf, PAGE_SIZE, "%s\n", entry->type);385}386 387static inline struct memmap_attribute *to_memmap_attr(struct attribute *attr)388{389 return container_of(attr, struct memmap_attribute, attr);390}391 392static ssize_t memmap_attr_show(struct kobject *kobj,393 struct attribute *attr, char *buf)394{395 struct firmware_map_entry *entry = to_memmap_entry(kobj);396 struct memmap_attribute *memmap_attr = to_memmap_attr(attr);397 398 return memmap_attr->show(entry, buf);399}400 401/*402 * Initialises stuff and adds the entries in the map_entries list to403 * sysfs. Important is that firmware_map_add() and firmware_map_add_early()404 * must be called before late_initcall. That's just because that function405 * is called as late_initcall() function, which means that if you call406 * firmware_map_add() or firmware_map_add_early() afterwards, the entries407 * are not added to sysfs.408 */409static int __init firmware_memmap_init(void)410{411 struct firmware_map_entry *entry;412 413 list_for_each_entry(entry, &map_entries, list)414 add_sysfs_fw_map_entry(entry);415 416 return 0;417}418late_initcall(firmware_memmap_init);419 420