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- /*
- * efi.c - EFI subsystem
- *
- * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
- * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
- * Copyright (C) 2013 Tom Gundersen <teg@jklm.no>
- *
- * This code registers /sys/firmware/efi{,/efivars} when EFI is supported,
- * allowing the efivarfs to be mounted or the efivars module to be loaded.
- * The existance of /sys/firmware/efi may also be used by userspace to
- * determine that the system supports EFI.
- *
- * This file is released under the GPLv2.
- */
- #include <linux/kobject.h>
- #include <linux/module.h>
- #include <linux/init.h>
- #include <linux/device.h>
- #include <linux/efi.h>
- static struct kobject *efi_kobj;
- static struct kobject *efivars_kobj;
- /*
- * Let's not leave out systab information that snuck into
- * the efivars driver
- */
- static ssize_t systab_show(struct kobject *kobj,
- struct kobj_attribute *attr, char *buf)
- {
- char *str = buf;
- if (!kobj || !buf)
- return -EINVAL;
- if (efi.mps != EFI_INVALID_TABLE_ADDR)
- str += sprintf(str, "MPS=0x%lx\n", efi.mps);
- if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
- str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
- if (efi.acpi != EFI_INVALID_TABLE_ADDR)
- str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
- if (efi.smbios != EFI_INVALID_TABLE_ADDR)
- str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
- if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
- str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
- if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
- str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
- if (efi.uga != EFI_INVALID_TABLE_ADDR)
- str += sprintf(str, "UGA=0x%lx\n", efi.uga);
- return str - buf;
- }
- static struct kobj_attribute efi_attr_systab =
- __ATTR(systab, 0400, systab_show, NULL);
- static struct attribute *efi_subsys_attrs[] = {
- &efi_attr_systab.attr,
- NULL, /* maybe more in the future? */
- };
- static struct attribute_group efi_subsys_attr_group = {
- .attrs = efi_subsys_attrs,
- };
- static struct efivars generic_efivars;
- static struct efivar_operations generic_ops;
- static int generic_ops_register(void)
- {
- generic_ops.get_variable = efi.get_variable;
- generic_ops.set_variable = efi.set_variable;
- generic_ops.get_next_variable = efi.get_next_variable;
- generic_ops.query_variable_store = efi_query_variable_store;
- return efivars_register(&generic_efivars, &generic_ops, efi_kobj);
- }
- static void generic_ops_unregister(void)
- {
- efivars_unregister(&generic_efivars);
- }
- /*
- * We register the efi subsystem with the firmware subsystem and the
- * efivars subsystem with the efi subsystem, if the system was booted with
- * EFI.
- */
- static int __init efisubsys_init(void)
- {
- int error;
- if (!efi_enabled(EFI_BOOT))
- return 0;
- /* We register the efi directory at /sys/firmware/efi */
- efi_kobj = kobject_create_and_add("efi", firmware_kobj);
- if (!efi_kobj) {
- pr_err("efi: Firmware registration failed.\n");
- return -ENOMEM;
- }
- error = generic_ops_register();
- if (error)
- goto err_put;
- error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
- if (error) {
- pr_err("efi: Sysfs attribute export failed with error %d.\n",
- error);
- goto err_unregister;
- }
- /* and the standard mountpoint for efivarfs */
- efivars_kobj = kobject_create_and_add("efivars", efi_kobj);
- if (!efivars_kobj) {
- pr_err("efivars: Subsystem registration failed.\n");
- error = -ENOMEM;
- goto err_remove_group;
- }
- return 0;
- err_remove_group:
- sysfs_remove_group(efi_kobj, &efi_subsys_attr_group);
- err_unregister:
- generic_ops_unregister();
- err_put:
- kobject_put(efi_kobj);
- return error;
- }
- subsys_initcall(efisubsys_init);
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