diff options
Diffstat (limited to 'drivers/firmware/memmap.c')
| -rw-r--r-- | drivers/firmware/memmap.c | 419 |
1 files changed, 419 insertions, 0 deletions
diff --git a/drivers/firmware/memmap.c b/drivers/firmware/memmap.c new file mode 100644 index 0000000000..8e59be3782 --- /dev/null +++ b/drivers/firmware/memmap.c @@ -0,0 +1,419 @@ +// 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); + |