// SPDX-License-Identifier: GPL-2.0-only /* * linux/drivers/firmware/memmap.c * Copyright (C) 2008 SUSE LINUX Products GmbH * by Bernhard Walle <bernhard.walle@gmx.de> */ #include <linux/string.h> #include <linux/firmware-map.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/types.h> #include <linux/memblock.h> #include <linux/slab.h> #include <linux/mm.h> /* * Data types ------------------------------------------------------------------ */ /* * Firmware map entry. Because firmware memory maps are flat and not * hierarchical, it's ok to organise them in a linked list. No parent * information is necessary as for the resource tree. */ struct firmware_map_entry { /* * start and end must be u64 rather than resource_size_t, because e820 * resources can lie at addresses above 4G. */ u64 start; /* start of the memory range */ u64 end; /* end of the memory range (incl.) */ const char *type; /* type of the memory range */ struct list_head list; /* entry for the linked list */ struct kobject kobj; /* kobject for each entry */ }; /* * Forward declarations -------------------------------------------------------- */ static ssize_t memmap_attr_show(struct kobject *kobj, struct attribute *attr, char *buf); static ssize_t start_show(struct firmware_map_entry *entry, char *buf); static ssize_t end_show(struct firmware_map_entry *entry, char *buf); static ssize_t type_show(struct firmware_map_entry *entry, char *buf); static struct firmware_map_entry * __meminit firmware_map_find_entry(u64 start, u64 end, const char *type); /* * Static data ----------------------------------------------------------------- */ struct memmap_attribute { struct attribute attr; ssize_t (*show)(struct firmware_map_entry *entry, char *buf); }; static struct memmap_attribute memmap_start_attr = __ATTR_RO(start); static struct memmap_attribute memmap_end_attr = __ATTR_RO(end); static struct memmap_attribute memmap_type_attr = __ATTR_RO(type); /* * These are default attributes that are added for every memmap entry. */ static struct attribute *def_attrs[] = { &memmap_start_attr.attr, &memmap_end_attr.attr, &memmap_type_attr.attr, NULL }; ATTRIBUTE_GROUPS(def); static const struct sysfs_ops memmap_attr_ops = { .show = memmap_attr_show, }; /* Firmware memory map entries. */ static LIST_HEAD(map_entries); static DEFINE_SPINLOCK(map_entries_lock); /* * For memory hotplug, there is no way to free memory map entries allocated * by boot mem after the system is up. So when we hot-remove memory whose * map entry is allocated by bootmem, we need to remember the storage and * reuse it when the memory is hot-added again. */ static LIST_HEAD(map_entries_bootmem); static DEFINE_SPINLOCK(map_entries_bootmem_lock); static inline struct firmware_map_entry * to_memmap_entry(struct kobject *kobj) { return container_of(kobj, struct firmware_map_entry, kobj); } static void __meminit release_firmware_map_entry(struct kobject *kobj) { struct firmware_map_entry *entry = to_memmap_entry(kobj); if (PageReserved(virt_to_page(entry))) { /* * Remember the storage allocated by bootmem, and reuse it when * the memory is hot-added again. The entry will be added to * map_entries_bootmem here, and deleted from &map_entries in * firmware_map_remove_entry(). */ spin_lock(&map_entries_bootmem_lock); list_add(&entry->list, &map_entries_bootmem); spin_unlock(&map_entries_bootmem_lock); return; } kfree(entry); } static struct kobj_type __refdata memmap_ktype = { .release = release_firmware_map_entry, .sysfs_ops = &memmap_attr_ops, .default_groups = def_groups, }; /* * Registration functions ------------------------------------------------------ */ /** * firmware_map_add_entry() - Does the real work to add a firmware memmap entry. * @start: Start of the memory range. * @end: End of the memory range (exclusive). * @type: Type of the memory range. * @entry: Pre-allocated (either kmalloc() or bootmem allocator), uninitialised * entry. * * Common implementation of firmware_map_add() and firmware_map_add_early() * which expects a pre-allocated struct firmware_map_entry. * * Return: 0 always */ static int firmware_map_add_entry(u64 start, u64 end, const char *type, struct firmware_map_entry *entry) { BUG_ON(start > end); entry->start = start; entry->end = end - 1; entry->type = type; INIT_LIST_HEAD(&entry->list); kobject_init(&entry->kobj, &memmap_ktype); spin_lock(&map_entries_lock); list_add_tail(&entry->list, &map_entries); spin_unlock(&map_entries_lock); return 0; } /** * firmware_map_remove_entry() - Does the real work to remove a firmware * memmap entry. * @entry: removed entry. * * The caller must hold map_entries_lock, and release it properly. */ static inline void firmware_map_remove_entry(struct firmware_map_entry *entry) { list_del(&entry->list); } /* * Add memmap entry on sysfs */ static int add_sysfs_fw_map_entry(struct firmware_map_entry *entry) { static int map_entries_nr; static struct kset *mmap_kset; if (entry->kobj.state_in_sysfs) return -EEXIST; if (!mmap_kset) { mmap_kset = kset_create_and_add("memmap", NULL, firmware_kobj); if (!mmap_kset) return -ENOMEM; } entry->kobj.kset = mmap_kset; if (kobject_add(&entry->kobj, NULL, "%d", map_entries_nr++)) kobject_put(&entry->kobj); return 0; } /* * Remove memmap entry on sysfs */ static inline void remove_sysfs_fw_map_entry(struct firmware_map_entry *entry) { kobject_put(&entry->kobj); } /** * firmware_map_find_entry_in_list() - Search memmap entry in a given list. * @start: Start of the memory range. * @end: End of the memory range (exclusive). * @type: Type of the memory range. * @list: In which to find the entry. * * This function is to find the memmap entey of a given memory range in a * given list. The caller must hold map_entries_lock, and must not release * the lock until the processing of the returned entry has completed. * * Return: Pointer to the entry to be found on success, or NULL on failure. */ static struct firmware_map_entry * __meminit firmware_map_find_entry_in_list(u64 start, u64 end, const char *type, struct list_head *list) { struct firmware_map_entry *entry; list_for_each_entry(entry, list, list) if ((entry->start == start) && (entry->end == end) && (!strcmp(entry->type, type))) { return entry; } return NULL; } /** * firmware_map_find_entry() - Search memmap entry in map_entries. * @start: Start of the memory range. * @end: End of the memory range (exclusive). * @type: Type of the memory range. * * This function is to find the memmap entey of a given memory range. * The caller must hold map_entries_lock, and must not release the lock * until the processing of the returned entry has completed. * * Return: Pointer to the entry to be found on success, or NULL on failure. */ static struct firmware_map_entry * __meminit firmware_map_find_entry(u64 start, u64 end, const char *type) { return firmware_map_find_entry_in_list(start, end, type, &map_entries); } /** * firmware_map_find_entry_bootmem() - Search memmap entry in map_entries_bootmem. * @start: Start of the memory range. * @end: End of the memory range (exclusive). * @type: Type of the memory range. * * This function is similar to firmware_map_find_entry except that it find the * given entry in map_entries_bootmem. * * Return: Pointer to the entry to be found on success, or NULL on failure. */ static struct firmware_map_entry * __meminit firmware_map_find_entry_bootmem(u64 start, u64 end, const char *type) { return firmware_map_find_entry_in_list(start, end, type, &map_entries_bootmem); } /** * firmware_map_add_hotplug() - Adds a firmware mapping entry when we do * memory hotplug. * @start: Start of the memory range. * @end: End of the memory range (exclusive) * @type: Type of the memory range. * * Adds a firmware mapping entry. This function is for memory hotplug, it is * similar to function firmware_map_add_early(). The only difference is that * it will create the syfs entry dynamically. * * Return: 0 on success, or -ENOMEM if no memory could be allocated. */ int __meminit firmware_map_add_hotplug(u64 start, u64 end, const char *type) { struct firmware_map_entry *entry; entry = firmware_map_find_entry(start, end - 1, type); if (entry) return 0; entry = firmware_map_find_entry_bootmem(start, end - 1, type); if (!entry) { entry = kzalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC); if (!entry) return -ENOMEM; } else { /* Reuse storage allocated by bootmem. */ spin_lock(&map_entries_bootmem_lock); list_del(&entry->list); spin_unlock(&map_entries_bootmem_lock); memset(entry, 0, sizeof(*entry)); } firmware_map_add_entry(start, end, type, entry); /* create the memmap entry */ add_sysfs_fw_map_entry(entry); return 0; } /** * firmware_map_add_early() - Adds a firmware mapping entry. * @start: Start of the memory range. * @end: End of the memory range. * @type: Type of the memory range. * * Adds a firmware mapping entry. This function uses the bootmem allocator * for memory allocation. * * That function must be called before late_initcall. * * Return: 0 on success, or -ENOMEM if no memory could be allocated. */ int __init firmware_map_add_early(u64 start, u64 end, const char *type) { struct firmware_map_entry *entry; entry = memblock_alloc(sizeof(struct firmware_map_entry), SMP_CACHE_BYTES); if (WARN_ON(!entry)) return -ENOMEM; return firmware_map_add_entry(start, end, type, entry); } /** * firmware_map_remove() - remove a firmware mapping entry * @start: Start of the memory range. * @end: End of the memory range. * @type: Type of the memory range. * * removes a firmware mapping entry. * * Return: 0 on success, or -EINVAL if no entry. */ int __meminit firmware_map_remove(u64 start, u64 end, const char *type) { struct firmware_map_entry *entry; spin_lock(&map_entries_lock); entry = firmware_map_find_entry(start, end - 1, type); if (!entry) { spin_unlock(&map_entries_lock); return -EINVAL; } firmware_map_remove_entry(entry); spin_unlock(&map_entries_lock); /* remove the memmap entry */ remove_sysfs_fw_map_entry(entry); return 0; } /* * Sysfs functions ------------------------------------------------------------- */ static ssize_t start_show(struct firmware_map_entry *entry, char *buf) { return snprintf(buf, PAGE_SIZE, "0x%llx\n", (unsigned long long)entry->start); } static ssize_t end_show(struct firmware_map_entry *entry, char *buf) { return snprintf(buf, PAGE_SIZE, "0x%llx\n", (unsigned long long)entry->end); } static ssize_t type_show(struct firmware_map_entry *entry, char *buf) { return snprintf(buf, PAGE_SIZE, "%s\n", entry->type); } static inline struct memmap_attribute *to_memmap_attr(struct attribute *attr) { return container_of(attr, struct memmap_attribute, attr); } static ssize_t memmap_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { struct firmware_map_entry *entry = to_memmap_entry(kobj); struct memmap_attribute *memmap_attr = to_memmap_attr(attr); return memmap_attr->show(entry, buf); } /* * Initialises stuff and adds the entries in the map_entries list to * sysfs. Important is that firmware_map_add() and firmware_map_add_early() * must be called before late_initcall. That's just because that function * is called as late_initcall() function, which means that if you call * firmware_map_add() or firmware_map_add_early() afterwards, the entries * are not added to sysfs. */ static int __init firmware_memmap_init(void) { struct firmware_map_entry *entry; list_for_each_entry(entry, &map_entries, list) add_sysfs_fw_map_entry(entry); return 0; } late_initcall(firmware_memmap_init);