| /* |
| * esrt.c |
| * |
| * This module exports EFI System Resource Table (ESRT) entries into userspace |
| * through the sysfs file system. The ESRT provides a read-only catalog of |
| * system components for which the system accepts firmware upgrades via UEFI's |
| * "Capsule Update" feature. This module allows userland utilities to evaluate |
| * what firmware updates can be applied to this system, and potentially arrange |
| * for those updates to occur. |
| * |
| * Data is currently found below /sys/firmware/efi/esrt/... |
| */ |
| #define pr_fmt(fmt) "esrt: " fmt |
| |
| #include <linux/capability.h> |
| #include <linux/device.h> |
| #include <linux/efi.h> |
| #include <linux/init.h> |
| #include <linux/kernel.h> |
| #include <linux/kobject.h> |
| #include <linux/list.h> |
| #include <linux/memblock.h> |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| #include <linux/types.h> |
| |
| #include <asm/io.h> |
| #include <asm/early_ioremap.h> |
| |
| struct efi_system_resource_entry_v1 { |
| efi_guid_t fw_class; |
| u32 fw_type; |
| u32 fw_version; |
| u32 lowest_supported_fw_version; |
| u32 capsule_flags; |
| u32 last_attempt_version; |
| u32 last_attempt_status; |
| }; |
| |
| /* |
| * _count and _version are what they seem like. _max is actually just |
| * accounting info for the firmware when creating the table; it should never |
| * have been exposed to us. To wit, the spec says: |
| * The maximum number of resource array entries that can be within the |
| * table without reallocating the table, must not be zero. |
| * Since there's no guidance about what that means in terms of memory layout, |
| * it means nothing to us. |
| */ |
| struct efi_system_resource_table { |
| u32 fw_resource_count; |
| u32 fw_resource_count_max; |
| u64 fw_resource_version; |
| u8 entries[]; |
| }; |
| |
| static phys_addr_t esrt_data; |
| static size_t esrt_data_size; |
| |
| static struct efi_system_resource_table *esrt; |
| |
| struct esre_entry { |
| union { |
| struct efi_system_resource_entry_v1 *esre1; |
| } esre; |
| |
| struct kobject kobj; |
| struct list_head list; |
| }; |
| |
| /* global list of esre_entry. */ |
| static LIST_HEAD(entry_list); |
| |
| /* entry attribute */ |
| struct esre_attribute { |
| struct attribute attr; |
| ssize_t (*show)(struct esre_entry *entry, char *buf); |
| ssize_t (*store)(struct esre_entry *entry, |
| const char *buf, size_t count); |
| }; |
| |
| static struct esre_entry *to_entry(struct kobject *kobj) |
| { |
| return container_of(kobj, struct esre_entry, kobj); |
| } |
| |
| static struct esre_attribute *to_attr(struct attribute *attr) |
| { |
| return container_of(attr, struct esre_attribute, attr); |
| } |
| |
| static ssize_t esre_attr_show(struct kobject *kobj, |
| struct attribute *_attr, char *buf) |
| { |
| struct esre_entry *entry = to_entry(kobj); |
| struct esre_attribute *attr = to_attr(_attr); |
| |
| /* Don't tell normal users what firmware versions we've got... */ |
| if (!capable(CAP_SYS_ADMIN)) |
| return -EACCES; |
| |
| return attr->show(entry, buf); |
| } |
| |
| static const struct sysfs_ops esre_attr_ops = { |
| .show = esre_attr_show, |
| }; |
| |
| /* Generic ESRT Entry ("ESRE") support. */ |
| static ssize_t esre_fw_class_show(struct esre_entry *entry, char *buf) |
| { |
| char *str = buf; |
| |
| efi_guid_to_str(&entry->esre.esre1->fw_class, str); |
| str += strlen(str); |
| str += sprintf(str, "\n"); |
| |
| return str - buf; |
| } |
| |
| static struct esre_attribute esre_fw_class = __ATTR(fw_class, 0400, |
| esre_fw_class_show, NULL); |
| |
| #define esre_attr_decl(name, size, fmt) \ |
| static ssize_t esre_##name##_show(struct esre_entry *entry, char *buf) \ |
| { \ |
| return sprintf(buf, fmt "\n", \ |
| le##size##_to_cpu(entry->esre.esre1->name)); \ |
| } \ |
| \ |
| static struct esre_attribute esre_##name = __ATTR(name, 0400, \ |
| esre_##name##_show, NULL) |
| |
| esre_attr_decl(fw_type, 32, "%u"); |
| esre_attr_decl(fw_version, 32, "%u"); |
| esre_attr_decl(lowest_supported_fw_version, 32, "%u"); |
| esre_attr_decl(capsule_flags, 32, "0x%x"); |
| esre_attr_decl(last_attempt_version, 32, "%u"); |
| esre_attr_decl(last_attempt_status, 32, "%u"); |
| |
| static struct attribute *esre1_attrs[] = { |
| &esre_fw_class.attr, |
| &esre_fw_type.attr, |
| &esre_fw_version.attr, |
| &esre_lowest_supported_fw_version.attr, |
| &esre_capsule_flags.attr, |
| &esre_last_attempt_version.attr, |
| &esre_last_attempt_status.attr, |
| NULL |
| }; |
| static void esre_release(struct kobject *kobj) |
| { |
| struct esre_entry *entry = to_entry(kobj); |
| |
| list_del(&entry->list); |
| kfree(entry); |
| } |
| |
| static struct kobj_type esre1_ktype = { |
| .release = esre_release, |
| .sysfs_ops = &esre_attr_ops, |
| .default_attrs = esre1_attrs, |
| }; |
| |
| |
| static struct kobject *esrt_kobj; |
| static struct kset *esrt_kset; |
| |
| static int esre_create_sysfs_entry(void *esre, int entry_num) |
| { |
| int rc = 0; |
| struct esre_entry *entry; |
| char name[20]; |
| |
| entry = kzalloc(sizeof(*entry), GFP_KERNEL); |
| if (!entry) |
| return -ENOMEM; |
| |
| sprintf(name, "entry%d", entry_num); |
| |
| entry->kobj.kset = esrt_kset; |
| |
| if (esrt->fw_resource_version == 1) { |
| entry->esre.esre1 = esre; |
| rc = kobject_init_and_add(&entry->kobj, &esre1_ktype, NULL, |
| "%s", name); |
| } |
| if (rc) { |
| kfree(entry); |
| return rc; |
| } |
| |
| list_add_tail(&entry->list, &entry_list); |
| return 0; |
| } |
| |
| /* support for displaying ESRT fields at the top level */ |
| #define esrt_attr_decl(name, size, fmt) \ |
| static ssize_t esrt_##name##_show(struct kobject *kobj, \ |
| struct kobj_attribute *attr, char *buf)\ |
| { \ |
| return sprintf(buf, fmt "\n", le##size##_to_cpu(esrt->name)); \ |
| } \ |
| \ |
| static struct kobj_attribute esrt_##name = __ATTR(name, 0400, \ |
| esrt_##name##_show, NULL) |
| |
| esrt_attr_decl(fw_resource_count, 32, "%u"); |
| esrt_attr_decl(fw_resource_count_max, 32, "%u"); |
| esrt_attr_decl(fw_resource_version, 64, "%llu"); |
| |
| static struct attribute *esrt_attrs[] = { |
| &esrt_fw_resource_count.attr, |
| &esrt_fw_resource_count_max.attr, |
| &esrt_fw_resource_version.attr, |
| NULL, |
| }; |
| |
| static inline int esrt_table_exists(void) |
| { |
| if (!efi_enabled(EFI_CONFIG_TABLES)) |
| return 0; |
| if (efi.esrt == EFI_INVALID_TABLE_ADDR) |
| return 0; |
| return 1; |
| } |
| |
| static umode_t esrt_attr_is_visible(struct kobject *kobj, |
| struct attribute *attr, int n) |
| { |
| if (!esrt_table_exists()) |
| return 0; |
| return attr->mode; |
| } |
| |
| static struct attribute_group esrt_attr_group = { |
| .attrs = esrt_attrs, |
| .is_visible = esrt_attr_is_visible, |
| }; |
| |
| /* |
| * remap the table, copy it to kmalloced pages, and unmap it. |
| */ |
| void __init efi_esrt_init(void) |
| { |
| void *va; |
| struct efi_system_resource_table tmpesrt; |
| struct efi_system_resource_entry_v1 *v1_entries; |
| size_t size, max, entry_size, entries_size; |
| efi_memory_desc_t md; |
| int rc; |
| |
| pr_debug("esrt-init: loading.\n"); |
| if (!esrt_table_exists()) |
| return; |
| |
| rc = efi_mem_desc_lookup(efi.esrt, &md); |
| if (rc < 0) { |
| pr_err("ESRT header is not in the memory map.\n"); |
| return; |
| } |
| |
| max = efi_mem_desc_end(&md); |
| if (max < efi.esrt) { |
| pr_err("EFI memory descriptor is invalid. (esrt: %p max: %p)\n", |
| (void *)efi.esrt, (void *)max); |
| return; |
| } |
| |
| size = sizeof(*esrt); |
| max -= efi.esrt; |
| |
| if (max < size) { |
| pr_err("ESRT header doen't fit on single memory map entry. (size: %zu max: %zu)\n", |
| size, max); |
| return; |
| } |
| |
| va = early_memremap(efi.esrt, size); |
| if (!va) { |
| pr_err("early_memremap(%p, %zu) failed.\n", (void *)efi.esrt, |
| size); |
| return; |
| } |
| |
| memcpy(&tmpesrt, va, sizeof(tmpesrt)); |
| |
| if (tmpesrt.fw_resource_version == 1) { |
| entry_size = sizeof (*v1_entries); |
| } else { |
| pr_err("Unsupported ESRT version %lld.\n", |
| tmpesrt.fw_resource_version); |
| return; |
| } |
| |
| if (tmpesrt.fw_resource_count > 0 && max - size < entry_size) { |
| pr_err("ESRT memory map entry can only hold the header. (max: %zu size: %zu)\n", |
| max - size, entry_size); |
| goto err_memunmap; |
| } |
| |
| /* |
| * The format doesn't really give us any boundary to test here, |
| * so I'm making up 128 as the max number of individually updatable |
| * components we support. |
| * 128 should be pretty excessive, but there's still some chance |
| * somebody will do that someday and we'll need to raise this. |
| */ |
| if (tmpesrt.fw_resource_count > 128) { |
| pr_err("ESRT says fw_resource_count has very large value %d.\n", |
| tmpesrt.fw_resource_count); |
| goto err_memunmap; |
| } |
| |
| /* |
| * We know it can't be larger than N * sizeof() here, and N is limited |
| * by the previous test to a small number, so there's no overflow. |
| */ |
| entries_size = tmpesrt.fw_resource_count * entry_size; |
| if (max < size + entries_size) { |
| pr_err("ESRT does not fit on single memory map entry (size: %zu max: %zu)\n", |
| size, max); |
| goto err_memunmap; |
| } |
| |
| /* remap it with our (plausible) new pages */ |
| early_memunmap(va, size); |
| size += entries_size; |
| va = early_memremap(efi.esrt, size); |
| if (!va) { |
| pr_err("early_memremap(%p, %zu) failed.\n", (void *)efi.esrt, |
| size); |
| return; |
| } |
| |
| esrt_data = (phys_addr_t)efi.esrt; |
| esrt_data_size = size; |
| |
| pr_info("Reserving ESRT space from %p to %p.\n", (void *)esrt_data, |
| (char *)esrt_data + size); |
| memblock_reserve(esrt_data, esrt_data_size); |
| |
| pr_debug("esrt-init: loaded.\n"); |
| err_memunmap: |
| early_memunmap(va, size); |
| } |
| |
| static int __init register_entries(void) |
| { |
| struct efi_system_resource_entry_v1 *v1_entries = (void *)esrt->entries; |
| int i, rc; |
| |
| if (!esrt_table_exists()) |
| return 0; |
| |
| for (i = 0; i < le32_to_cpu(esrt->fw_resource_count); i++) { |
| void *entry; |
| if (esrt->fw_resource_version == 1) { |
| entry = &v1_entries[i]; |
| } |
| rc = esre_create_sysfs_entry(entry, i); |
| if (rc < 0) { |
| pr_err("ESRT entry creation failed with error %d.\n", |
| rc); |
| return rc; |
| } |
| } |
| return 0; |
| } |
| |
| static void cleanup_entry_list(void) |
| { |
| struct esre_entry *entry, *next; |
| |
| list_for_each_entry_safe(entry, next, &entry_list, list) { |
| kobject_put(&entry->kobj); |
| } |
| } |
| |
| static int __init esrt_sysfs_init(void) |
| { |
| int error; |
| struct efi_system_resource_table __iomem *ioesrt; |
| |
| pr_debug("esrt-sysfs: loading.\n"); |
| if (!esrt_data || !esrt_data_size) |
| return -ENOSYS; |
| |
| ioesrt = ioremap(esrt_data, esrt_data_size); |
| if (!ioesrt) { |
| pr_err("ioremap(%p, %zu) failed.\n", (void *)esrt_data, |
| esrt_data_size); |
| return -ENOMEM; |
| } |
| |
| esrt = kmalloc(esrt_data_size, GFP_KERNEL); |
| if (!esrt) { |
| pr_err("kmalloc failed. (wanted %zu bytes)\n", esrt_data_size); |
| iounmap(ioesrt); |
| return -ENOMEM; |
| } |
| |
| memcpy_fromio(esrt, ioesrt, esrt_data_size); |
| |
| esrt_kobj = kobject_create_and_add("esrt", efi_kobj); |
| if (!esrt_kobj) { |
| pr_err("Firmware table registration failed.\n"); |
| error = -ENOMEM; |
| goto err; |
| } |
| |
| error = sysfs_create_group(esrt_kobj, &esrt_attr_group); |
| if (error) { |
| pr_err("Sysfs attribute export failed with error %d.\n", |
| error); |
| goto err_remove_esrt; |
| } |
| |
| esrt_kset = kset_create_and_add("entries", NULL, esrt_kobj); |
| if (!esrt_kset) { |
| pr_err("kset creation failed.\n"); |
| error = -ENOMEM; |
| goto err_remove_group; |
| } |
| |
| error = register_entries(); |
| if (error) |
| goto err_cleanup_list; |
| |
| memblock_remove(esrt_data, esrt_data_size); |
| |
| pr_debug("esrt-sysfs: loaded.\n"); |
| |
| return 0; |
| err_cleanup_list: |
| cleanup_entry_list(); |
| kset_unregister(esrt_kset); |
| err_remove_group: |
| sysfs_remove_group(esrt_kobj, &esrt_attr_group); |
| err_remove_esrt: |
| kobject_put(esrt_kobj); |
| err: |
| kfree(esrt); |
| esrt = NULL; |
| return error; |
| } |
| |
| static void __exit esrt_sysfs_exit(void) |
| { |
| pr_debug("esrt-sysfs: unloading.\n"); |
| cleanup_entry_list(); |
| kset_unregister(esrt_kset); |
| sysfs_remove_group(esrt_kobj, &esrt_attr_group); |
| kfree(esrt); |
| esrt = NULL; |
| kobject_del(esrt_kobj); |
| kobject_put(esrt_kobj); |
| } |
| |
| module_init(esrt_sysfs_init); |
| module_exit(esrt_sysfs_exit); |
| |
| MODULE_AUTHOR("Peter Jones <pjones@redhat.com>"); |
| MODULE_DESCRIPTION("EFI System Resource Table support"); |
| MODULE_LICENSE("GPL"); |