File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/drivers/firmware/efi/reboot.c b/drivers/firmware/efi/reboot.c
new file mode 100644
index 0000000..9c59d1c
--- /dev/null
+++ b/drivers/firmware/efi/reboot.c
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2014 Intel Corporation; author Matt Fleming
+ * Copyright (c) 2014 Red Hat, Inc., Mark Salter <msalter@redhat.com>
+ */
+#include <linux/efi.h>
+#include <linux/reboot.h>
+
+int efi_reboot_quirk_mode = -1;
+
+void efi_reboot(enum reboot_mode reboot_mode, const char *__unused)
+{
+	int efi_mode;
+
+	if (!efi_enabled(EFI_RUNTIME_SERVICES))
+		return;
+
+	switch (reboot_mode) {
+	case REBOOT_WARM:
+	case REBOOT_SOFT:
+		efi_mode = EFI_RESET_WARM;
+		break;
+	default:
+		efi_mode = EFI_RESET_COLD;
+		break;
+	}
+
+	/*
+	 * If a quirk forced an EFI reset mode, always use that.
+	 */
+	if (efi_reboot_quirk_mode != -1)
+		efi_mode = efi_reboot_quirk_mode;
+
+	efi.reset_system(efi_mode, EFI_SUCCESS, 0, NULL);
+}
+
+bool __weak efi_poweroff_required(void)
+{
+	return false;
+}
+
+static void efi_power_off(void)
+{
+	efi.reset_system(EFI_RESET_SHUTDOWN, EFI_SUCCESS, 0, NULL);
+}
+
+static int __init efi_shutdown_init(void)
+{
+	if (!efi_enabled(EFI_RUNTIME_SERVICES))
+		return -ENODEV;
+
+	if (efi_poweroff_required())
+		pm_power_off = efi_power_off;
+
+	return 0;
+}
+late_initcall(efi_shutdown_init);