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- /*
- * 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/io.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 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_RO_MODE(fw_class, 0400);
- #define esre_attr_decl(name, size, fmt) \
- static ssize_t 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_RO_MODE(name, 0400)
- 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;
- entry = kzalloc(sizeof(*entry), GFP_KERNEL);
- if (!entry)
- return -ENOMEM;
- 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,
- "entry%d", entry_num);
- 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 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_RO_MODE(name, 0400)
- 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 const struct attribute_group esrt_attr_group = {
- .attrs = esrt_attrs,
- .is_visible = esrt_attr_is_visible,
- };
- /*
- * remap the table, validate it, mark it reserved 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 ||
- (!(md.attribute & EFI_MEMORY_RUNTIME) &&
- md.type != EFI_BOOT_SERVICES_DATA &&
- md.type != EFI_RUNTIME_SERVICES_DATA)) {
- pr_warn("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 doesn'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));
- early_memunmap(va, size);
- 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);
- return;
- }
- /*
- * 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);
- return;
- }
- /*
- * 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);
- return;
- }
- size += entries_size;
- 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);
- if (md.type == EFI_BOOT_SERVICES_DATA)
- efi_mem_reserve(esrt_data, esrt_data_size);
- pr_debug("esrt-init: loaded.\n");
- }
- 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;
- pr_debug("esrt-sysfs: loading.\n");
- if (!esrt_data || !esrt_data_size)
- return -ENOSYS;
- esrt = memremap(esrt_data, esrt_data_size, MEMREMAP_WB);
- if (!esrt) {
- pr_err("memremap(%pa, %zu) failed.\n", &esrt_data,
- esrt_data_size);
- return -ENOMEM;
- }
- 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;
- 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:
- memunmap(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");
- */
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