diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/firmware/efi/Kconfig | 15 | ||||
| -rw-r--r-- | drivers/firmware/efi/Makefile | 1 | ||||
| -rw-r--r-- | drivers/firmware/efi/efibc.c | 101 |
3 files changed, 117 insertions, 0 deletions
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig index e1670d5..0b0b635 100644 --- a/drivers/firmware/efi/Kconfig +++ b/drivers/firmware/efi/Kconfig @@ -87,6 +87,21 @@ config EFI_RUNTIME_WRAPPERS config EFI_ARMSTUB bool +config EFI_BOOTLOADER_CONTROL + tristate "EFI Bootloader Control" + depends on EFI_VARS + default n + ---help--- + This module installs a reboot hook, such that if reboot() is + invoked with a string argument NNN, "NNN" is copied to the + "LoaderEntryOneShot" EFI variable, to be read by the + bootloader. If the string matches one of the boot labels + defined in its configuration, the bootloader will boot once + to that label. The "LoaderEntryRebootReason" EFI variable is + set with the reboot reason: "reboot" or "shutdown". The + bootloader reads this reboot reason and takes particular + action according to its policy. + endmenu config UEFI_CPER diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile index d5be623..b080808 100644 --- a/drivers/firmware/efi/Makefile +++ b/drivers/firmware/efi/Makefile @@ -18,6 +18,7 @@ obj-$(CONFIG_EFI_RUNTIME_MAP) += runtime-map.o obj-$(CONFIG_EFI_RUNTIME_WRAPPERS) += runtime-wrappers.o obj-$(CONFIG_EFI_STUB) += libstub/ obj-$(CONFIG_EFI_FAKE_MEMMAP) += fake_mem.o +obj-$(CONFIG_EFI_BOOTLOADER_CONTROL) += efibc.o arm-obj-$(CONFIG_EFI) := arm-init.o arm-runtime.o obj-$(CONFIG_ARM) += $(arm-obj-y) diff --git a/drivers/firmware/efi/efibc.c b/drivers/firmware/efi/efibc.c new file mode 100644 index 0000000..2e0c7cc --- /dev/null +++ b/drivers/firmware/efi/efibc.c @@ -0,0 +1,101 @@ +/* + * efibc: control EFI bootloaders which obey LoaderEntryOneShot var + * Copyright (c) 2013-2016, Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +#define pr_fmt(fmt) "efibc: " fmt + +#include <linux/efi.h> +#include <linux/module.h> +#include <linux/reboot.h> + +static void efibc_str_to_str16(const char *str, efi_char16_t *str16) +{ + size_t i; + + for (i = 0; i < strlen(str); i++) + str16[i] = str[i]; + + str16[i] = '\0'; +} + +static void efibc_set_variable(const char *name, const char *value) +{ + int ret; + efi_guid_t guid = LINUX_EFI_LOADER_ENTRY_GUID; + struct efivar_entry entry; + size_t size = (strlen(value) + 1) * sizeof(efi_char16_t); + + if (size > sizeof(entry.var.Data)) + pr_err("value is too large"); + + efibc_str_to_str16(name, entry.var.VariableName); + efibc_str_to_str16(value, (efi_char16_t *)entry.var.Data); + memcpy(&entry.var.VendorGuid, &guid, sizeof(guid)); + + ret = efivar_entry_set(&entry, + EFI_VARIABLE_NON_VOLATILE + | EFI_VARIABLE_BOOTSERVICE_ACCESS + | EFI_VARIABLE_RUNTIME_ACCESS, + size, entry.var.Data, NULL); + if (ret) + pr_err("failed to set %s EFI variable: 0x%x\n", + name, ret); +} + +static int efibc_reboot_notifier_call(struct notifier_block *notifier, + unsigned long event, void *data) +{ + const char *reason = "shutdown"; + + if (event == SYS_RESTART) + reason = "reboot"; + + efibc_set_variable("LoaderEntryRebootReason", reason); + + if (!data) + return NOTIFY_DONE; + + efibc_set_variable("LoaderEntryOneShot", (char *)data); + + return NOTIFY_DONE; +} + +static struct notifier_block efibc_reboot_notifier = { + .notifier_call = efibc_reboot_notifier_call, +}; + +static int __init efibc_init(void) +{ + int ret; + + if (!efi_enabled(EFI_RUNTIME_SERVICES)) + return -ENODEV; + + ret = register_reboot_notifier(&efibc_reboot_notifier); + if (ret) + pr_err("unable to register reboot notifier\n"); + + return ret; +} +module_init(efibc_init); + +static void __exit efibc_exit(void) +{ + unregister_reboot_notifier(&efibc_reboot_notifier); +} +module_exit(efibc_exit); + +MODULE_AUTHOR("Jeremy Compostella <jeremy.compostella@intel.com>"); +MODULE_AUTHOR("Matt Gumbel <matthew.k.gumbel@intel.com"); +MODULE_DESCRIPTION("EFI Bootloader Control"); +MODULE_LICENSE("GPL v2"); |