mirror of https://gitee.com/openkylin/linux.git
441 lines
10 KiB
C
441 lines
10 KiB
C
// 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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/* 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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kfree(entry);
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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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struct efi_system_resource_entry_v1 *v1_entries;
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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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entry_size = sizeof (*v1_entries);
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} else {
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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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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 <pjones@redhat.com>");
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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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