/* * efi.c - EFI subsystem * * Copyright (C) 2001,2003,2004 Dell * Copyright (C) 2004 Intel Corporation * Copyright (C) 2013 Tom Gundersen * * 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. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include struct efi __read_mostly efi = { .mps = EFI_INVALID_TABLE_ADDR, .acpi = EFI_INVALID_TABLE_ADDR, .acpi20 = EFI_INVALID_TABLE_ADDR, .smbios = EFI_INVALID_TABLE_ADDR, .sal_systab = EFI_INVALID_TABLE_ADDR, .boot_info = EFI_INVALID_TABLE_ADDR, .hcdp = EFI_INVALID_TABLE_ADDR, .uga = EFI_INVALID_TABLE_ADDR, .uv_systab = EFI_INVALID_TABLE_ADDR, }; EXPORT_SYMBOL(efi); 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); static __initdata efi_config_table_type_t common_tables[] = { {ACPI_20_TABLE_GUID, "ACPI 2.0", &efi.acpi20}, {ACPI_TABLE_GUID, "ACPI", &efi.acpi}, {HCDP_TABLE_GUID, "HCDP", &efi.hcdp}, {MPS_TABLE_GUID, "MPS", &efi.mps}, {SAL_SYSTEM_TABLE_GUID, "SALsystab", &efi.sal_systab}, {SMBIOS_TABLE_GUID, "SMBIOS", &efi.smbios}, {UGA_IO_PROTOCOL_GUID, "UGA", &efi.uga}, {NULL_GUID, NULL, 0}, }; static __init int match_config_table(efi_guid_t *guid, unsigned long table, efi_config_table_type_t *table_types) { u8 str[EFI_VARIABLE_GUID_LEN + 1]; int i; if (table_types) { efi_guid_unparse(guid, str); for (i = 0; efi_guidcmp(table_types[i].guid, NULL_GUID); i++) { efi_guid_unparse(&table_types[i].guid, str); if (!efi_guidcmp(*guid, table_types[i].guid)) { *(table_types[i].ptr) = table; pr_cont(" %s=0x%lx ", table_types[i].name, table); return 1; } } } return 0; } int __init efi_config_init(efi_config_table_type_t *arch_tables) { void *config_tables, *tablep; int i, sz; if (efi_enabled(EFI_64BIT)) sz = sizeof(efi_config_table_64_t); else sz = sizeof(efi_config_table_32_t); /* * Let's see what config tables the firmware passed to us. */ config_tables = early_memremap(efi.systab->tables, efi.systab->nr_tables * sz); if (config_tables == NULL) { pr_err("Could not map Configuration table!\n"); return -ENOMEM; } tablep = config_tables; pr_info(""); for (i = 0; i < efi.systab->nr_tables; i++) { efi_guid_t guid; unsigned long table; if (efi_enabled(EFI_64BIT)) { u64 table64; guid = ((efi_config_table_64_t *)tablep)->guid; table64 = ((efi_config_table_64_t *)tablep)->table; table = table64; #ifndef CONFIG_64BIT if (table64 >> 32) { pr_cont("\n"); pr_err("Table located above 4GB, disabling EFI.\n"); early_iounmap(config_tables, efi.systab->nr_tables * sz); return -EINVAL; } #endif } else { guid = ((efi_config_table_32_t *)tablep)->guid; table = ((efi_config_table_32_t *)tablep)->table; } if (!match_config_table(&guid, table, common_tables)) match_config_table(&guid, table, arch_tables); tablep += sz; } pr_cont("\n"); early_iounmap(config_tables, efi.systab->nr_tables * sz); return 0; }