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-rw-r--r--drivers/firmware/efi/Kconfig15
-rw-r--r--drivers/firmware/efi/Makefile1
-rw-r--r--drivers/firmware/efi/efibc.c101
-rw-r--r--include/linux/efi.h4
4 files changed, 121 insertions, 0 deletions
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index e1670d533f97..0b0b635aa101 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 d5be62399130..b0808080e744 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 000000000000..2e0c7ccd9d9e
--- /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");
diff --git a/include/linux/efi.h b/include/linux/efi.h
index e53458842245..4db7052b2699 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -642,6 +642,10 @@ void efi_native_runtime_setup(void);
EFI_GUID(0xe03fc20a, 0x85dc, 0x406e, \
0xb9, 0xe, 0x4a, 0xb5, 0x02, 0x37, 0x1d, 0x95)
+#define LINUX_EFI_LOADER_ENTRY_GUID \
+ EFI_GUID(0x4a67b082, 0x0a4c, 0x41cf, \
+ 0xb6, 0xc7, 0x44, 0x0b, 0x29, 0xbb, 0x8c, 0x4f)
+
typedef struct {
efi_guid_t guid;
u64 table;