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438 lines
10 KiB
438 lines
10 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* esrt.c |
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* |
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* This module exports EFI System Resource Table (ESRT) entries into userspace |
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* through the sysfs file system. The ESRT provides a read-only catalog of |
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* system components for which the system accepts firmware upgrades via UEFI's |
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* "Capsule Update" feature. This module allows userland utilities to evaluate |
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* what firmware updates can be applied to this system, and potentially arrange |
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* for those updates to occur. |
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* |
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* Data is currently found below /sys/firmware/efi/esrt/... |
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*/ |
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#define pr_fmt(fmt) "esrt: " fmt |
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#include <linux/capability.h> |
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#include <linux/device.h> |
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#include <linux/efi.h> |
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#include <linux/init.h> |
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#include <linux/io.h> |
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#include <linux/kernel.h> |
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#include <linux/kobject.h> |
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#include <linux/list.h> |
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#include <linux/memblock.h> |
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#include <linux/slab.h> |
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#include <linux/types.h> |
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#include <asm/io.h> |
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#include <asm/early_ioremap.h> |
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struct efi_system_resource_entry_v1 { |
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efi_guid_t fw_class; |
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u32 fw_type; |
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u32 fw_version; |
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u32 lowest_supported_fw_version; |
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u32 capsule_flags; |
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u32 last_attempt_version; |
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u32 last_attempt_status; |
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}; |
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/* |
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* _count and _version are what they seem like. _max is actually just |
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* accounting info for the firmware when creating the table; it should never |
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* have been exposed to us. To wit, the spec says: |
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* The maximum number of resource array entries that can be within the |
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* table without reallocating the table, must not be zero. |
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* Since there's no guidance about what that means in terms of memory layout, |
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* it means nothing to us. |
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*/ |
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struct efi_system_resource_table { |
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u32 fw_resource_count; |
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u32 fw_resource_count_max; |
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u64 fw_resource_version; |
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u8 entries[]; |
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}; |
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static phys_addr_t esrt_data; |
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static size_t esrt_data_size; |
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static struct efi_system_resource_table *esrt; |
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struct esre_entry { |
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union { |
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struct efi_system_resource_entry_v1 *esre1; |
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} esre; |
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struct kobject kobj; |
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struct list_head list; |
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}; |
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/* global list of esre_entry. */ |
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static LIST_HEAD(entry_list); |
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|
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/* entry attribute */ |
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struct esre_attribute { |
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struct attribute attr; |
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ssize_t (*show)(struct esre_entry *entry, char *buf); |
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ssize_t (*store)(struct esre_entry *entry, |
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const char *buf, size_t count); |
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}; |
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static struct esre_entry *to_entry(struct kobject *kobj) |
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{ |
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return container_of(kobj, struct esre_entry, kobj); |
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} |
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static struct esre_attribute *to_attr(struct attribute *attr) |
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{ |
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return container_of(attr, struct esre_attribute, attr); |
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} |
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static ssize_t esre_attr_show(struct kobject *kobj, |
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struct attribute *_attr, char *buf) |
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{ |
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struct esre_entry *entry = to_entry(kobj); |
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struct esre_attribute *attr = to_attr(_attr); |
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/* Don't tell normal users what firmware versions we've got... */ |
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if (!capable(CAP_SYS_ADMIN)) |
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return -EACCES; |
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return attr->show(entry, buf); |
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} |
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static const struct sysfs_ops esre_attr_ops = { |
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.show = esre_attr_show, |
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}; |
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/* Generic ESRT Entry ("ESRE") support. */ |
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static ssize_t fw_class_show(struct esre_entry *entry, char *buf) |
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{ |
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char *str = buf; |
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efi_guid_to_str(&entry->esre.esre1->fw_class, str); |
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str += strlen(str); |
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str += sprintf(str, "\n"); |
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return str - buf; |
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} |
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static struct esre_attribute esre_fw_class = __ATTR_RO_MODE(fw_class, 0400); |
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#define esre_attr_decl(name, size, fmt) \ |
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static ssize_t name##_show(struct esre_entry *entry, char *buf) \ |
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{ \ |
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return sprintf(buf, fmt "\n", \ |
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le##size##_to_cpu(entry->esre.esre1->name)); \ |
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} \ |
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\ |
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static struct esre_attribute esre_##name = __ATTR_RO_MODE(name, 0400) |
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esre_attr_decl(fw_type, 32, "%u"); |
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esre_attr_decl(fw_version, 32, "%u"); |
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esre_attr_decl(lowest_supported_fw_version, 32, "%u"); |
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esre_attr_decl(capsule_flags, 32, "0x%x"); |
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esre_attr_decl(last_attempt_version, 32, "%u"); |
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esre_attr_decl(last_attempt_status, 32, "%u"); |
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static struct attribute *esre1_attrs[] = { |
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&esre_fw_class.attr, |
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&esre_fw_type.attr, |
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&esre_fw_version.attr, |
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&esre_lowest_supported_fw_version.attr, |
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&esre_capsule_flags.attr, |
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&esre_last_attempt_version.attr, |
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&esre_last_attempt_status.attr, |
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NULL |
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}; |
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static void esre_release(struct kobject *kobj) |
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{ |
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struct esre_entry *entry = to_entry(kobj); |
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list_del(&entry->list); |
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kfree(entry); |
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} |
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static struct kobj_type esre1_ktype = { |
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.release = esre_release, |
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.sysfs_ops = &esre_attr_ops, |
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.default_attrs = esre1_attrs, |
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}; |
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static struct kobject *esrt_kobj; |
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static struct kset *esrt_kset; |
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static int esre_create_sysfs_entry(void *esre, int entry_num) |
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{ |
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struct esre_entry *entry; |
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entry = kzalloc(sizeof(*entry), GFP_KERNEL); |
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if (!entry) |
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return -ENOMEM; |
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entry->kobj.kset = esrt_kset; |
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if (esrt->fw_resource_version == 1) { |
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int rc = 0; |
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entry->esre.esre1 = esre; |
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rc = kobject_init_and_add(&entry->kobj, &esre1_ktype, NULL, |
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"entry%d", entry_num); |
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if (rc) { |
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kobject_put(&entry->kobj); |
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return rc; |
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} |
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} |
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list_add_tail(&entry->list, &entry_list); |
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return 0; |
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} |
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/* support for displaying ESRT fields at the top level */ |
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#define esrt_attr_decl(name, size, fmt) \ |
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static ssize_t name##_show(struct kobject *kobj, \ |
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struct kobj_attribute *attr, char *buf)\ |
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{ \ |
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return sprintf(buf, fmt "\n", le##size##_to_cpu(esrt->name)); \ |
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} \ |
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\ |
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static struct kobj_attribute esrt_##name = __ATTR_RO_MODE(name, 0400) |
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esrt_attr_decl(fw_resource_count, 32, "%u"); |
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esrt_attr_decl(fw_resource_count_max, 32, "%u"); |
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esrt_attr_decl(fw_resource_version, 64, "%llu"); |
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static struct attribute *esrt_attrs[] = { |
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&esrt_fw_resource_count.attr, |
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&esrt_fw_resource_count_max.attr, |
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&esrt_fw_resource_version.attr, |
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NULL, |
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}; |
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static inline int esrt_table_exists(void) |
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{ |
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if (!efi_enabled(EFI_CONFIG_TABLES)) |
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return 0; |
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if (efi.esrt == EFI_INVALID_TABLE_ADDR) |
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return 0; |
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return 1; |
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} |
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static umode_t esrt_attr_is_visible(struct kobject *kobj, |
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struct attribute *attr, int n) |
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{ |
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if (!esrt_table_exists()) |
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return 0; |
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return attr->mode; |
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} |
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static const struct attribute_group esrt_attr_group = { |
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.attrs = esrt_attrs, |
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.is_visible = esrt_attr_is_visible, |
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}; |
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/* |
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* remap the table, validate it, mark it reserved and unmap it. |
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*/ |
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void __init efi_esrt_init(void) |
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{ |
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void *va; |
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struct efi_system_resource_table tmpesrt; |
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size_t size, max, entry_size, entries_size; |
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efi_memory_desc_t md; |
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int rc; |
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phys_addr_t end; |
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if (!efi_enabled(EFI_MEMMAP)) |
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return; |
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pr_debug("esrt-init: loading.\n"); |
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if (!esrt_table_exists()) |
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return; |
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rc = efi_mem_desc_lookup(efi.esrt, &md); |
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if (rc < 0 || |
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(!(md.attribute & EFI_MEMORY_RUNTIME) && |
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md.type != EFI_BOOT_SERVICES_DATA && |
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md.type != EFI_RUNTIME_SERVICES_DATA)) { |
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pr_warn("ESRT header is not in the memory map.\n"); |
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return; |
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} |
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max = efi_mem_desc_end(&md); |
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if (max < efi.esrt) { |
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pr_err("EFI memory descriptor is invalid. (esrt: %p max: %p)\n", |
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(void *)efi.esrt, (void *)max); |
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return; |
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} |
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size = sizeof(*esrt); |
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max -= efi.esrt; |
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if (max < size) { |
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pr_err("ESRT header doesn't fit on single memory map entry. (size: %zu max: %zu)\n", |
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size, max); |
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return; |
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} |
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va = early_memremap(efi.esrt, size); |
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if (!va) { |
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pr_err("early_memremap(%p, %zu) failed.\n", (void *)efi.esrt, |
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size); |
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return; |
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} |
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memcpy(&tmpesrt, va, sizeof(tmpesrt)); |
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early_memunmap(va, size); |
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if (tmpesrt.fw_resource_version != 1) { |
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pr_err("Unsupported ESRT version %lld.\n", |
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tmpesrt.fw_resource_version); |
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return; |
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} |
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entry_size = sizeof(struct efi_system_resource_entry_v1); |
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if (tmpesrt.fw_resource_count > 0 && max - size < entry_size) { |
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pr_err("ESRT memory map entry can only hold the header. (max: %zu size: %zu)\n", |
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max - size, entry_size); |
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return; |
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} |
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/* |
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* The format doesn't really give us any boundary to test here, |
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* so I'm making up 128 as the max number of individually updatable |
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* components we support. |
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* 128 should be pretty excessive, but there's still some chance |
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* somebody will do that someday and we'll need to raise this. |
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*/ |
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if (tmpesrt.fw_resource_count > 128) { |
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pr_err("ESRT says fw_resource_count has very large value %d.\n", |
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tmpesrt.fw_resource_count); |
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return; |
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} |
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/* |
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* We know it can't be larger than N * sizeof() here, and N is limited |
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* by the previous test to a small number, so there's no overflow. |
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*/ |
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entries_size = tmpesrt.fw_resource_count * entry_size; |
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if (max < size + entries_size) { |
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pr_err("ESRT does not fit on single memory map entry (size: %zu max: %zu)\n", |
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size, max); |
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return; |
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} |
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size += entries_size; |
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esrt_data = (phys_addr_t)efi.esrt; |
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esrt_data_size = size; |
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end = esrt_data + size; |
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pr_info("Reserving ESRT space from %pa to %pa.\n", &esrt_data, &end); |
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if (md.type == EFI_BOOT_SERVICES_DATA) |
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efi_mem_reserve(esrt_data, esrt_data_size); |
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pr_debug("esrt-init: loaded.\n"); |
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} |
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static int __init register_entries(void) |
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{ |
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struct efi_system_resource_entry_v1 *v1_entries = (void *)esrt->entries; |
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int i, rc; |
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if (!esrt_table_exists()) |
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return 0; |
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for (i = 0; i < le32_to_cpu(esrt->fw_resource_count); i++) { |
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void *esre = NULL; |
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if (esrt->fw_resource_version == 1) { |
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esre = &v1_entries[i]; |
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} else { |
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pr_err("Unsupported ESRT version %lld.\n", |
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esrt->fw_resource_version); |
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return -EINVAL; |
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} |
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rc = esre_create_sysfs_entry(esre, i); |
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if (rc < 0) { |
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pr_err("ESRT entry creation failed with error %d.\n", |
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rc); |
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return rc; |
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} |
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} |
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return 0; |
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} |
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static void cleanup_entry_list(void) |
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{ |
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struct esre_entry *entry, *next; |
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list_for_each_entry_safe(entry, next, &entry_list, list) { |
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kobject_put(&entry->kobj); |
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} |
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} |
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static int __init esrt_sysfs_init(void) |
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{ |
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int error; |
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pr_debug("esrt-sysfs: loading.\n"); |
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if (!esrt_data || !esrt_data_size) |
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return -ENOSYS; |
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esrt = memremap(esrt_data, esrt_data_size, MEMREMAP_WB); |
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if (!esrt) { |
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pr_err("memremap(%pa, %zu) failed.\n", &esrt_data, |
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esrt_data_size); |
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return -ENOMEM; |
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} |
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esrt_kobj = kobject_create_and_add("esrt", efi_kobj); |
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if (!esrt_kobj) { |
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pr_err("Firmware table registration failed.\n"); |
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error = -ENOMEM; |
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goto err; |
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} |
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error = sysfs_create_group(esrt_kobj, &esrt_attr_group); |
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if (error) { |
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pr_err("Sysfs attribute export failed with error %d.\n", |
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error); |
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goto err_remove_esrt; |
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} |
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esrt_kset = kset_create_and_add("entries", NULL, esrt_kobj); |
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if (!esrt_kset) { |
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pr_err("kset creation failed.\n"); |
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error = -ENOMEM; |
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goto err_remove_group; |
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} |
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error = register_entries(); |
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if (error) |
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goto err_cleanup_list; |
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pr_debug("esrt-sysfs: loaded.\n"); |
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return 0; |
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err_cleanup_list: |
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cleanup_entry_list(); |
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kset_unregister(esrt_kset); |
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err_remove_group: |
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sysfs_remove_group(esrt_kobj, &esrt_attr_group); |
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err_remove_esrt: |
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kobject_put(esrt_kobj); |
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err: |
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memunmap(esrt); |
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esrt = NULL; |
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return error; |
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} |
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device_initcall(esrt_sysfs_init); |
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/* |
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MODULE_AUTHOR("Peter Jones <[email protected]>"); |
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MODULE_DESCRIPTION("EFI System Resource Table support"); |
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MODULE_LICENSE("GPL"); |
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*/
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