diff options
Diffstat (limited to 'kernel/drivers/firmware/efi/esrt.c')
| -rw-r--r-- | kernel/drivers/firmware/efi/esrt.c | 458 |
1 files changed, 458 insertions, 0 deletions
diff --git a/kernel/drivers/firmware/efi/esrt.c b/kernel/drivers/firmware/efi/esrt.c new file mode 100644 index 000000000..22c5285f7 --- /dev/null +++ b/kernel/drivers/firmware/efi/esrt.c @@ -0,0 +1,458 @@ +/* + * 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/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) +{ + 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) { + int rc = 0; + + 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; + phys_addr_t end; + + 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; + + end = esrt_data + size; + pr_info("Reserving ESRT space from %pa to %pa.\n", &esrt_data, &end); + 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 *esre = NULL; + if (esrt->fw_resource_version == 1) { + esre = &v1_entries[i]; + } else { + pr_err("Unsupported ESRT version %lld.\n", + esrt->fw_resource_version); + return -EINVAL; + } + + rc = esre_create_sysfs_entry(esre, 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(%pa, %zu) failed.\n", &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; +} +device_initcall(esrt_sysfs_init); + +/* +MODULE_AUTHOR("Peter Jones <pjones@redhat.com>"); +MODULE_DESCRIPTION("EFI System Resource Table support"); +MODULE_LICENSE("GPL"); +*/ |