| // 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 |
| }; |
| |
| 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_attrs = def_attrs, |
| }; |
| |
| /* |
| * 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); |
| |