efi/reboot: Add generic wrapper around EfiResetSystem()

Implement efi_reboot(), which is really just a wrapper around the
EfiResetSystem() EFI runtime service, but it does at least allow us to
funnel all callers through a single location.

It also simplifies the callsites since users no longer need to check to
see whether EFI_RUNTIME_SERVICES are enabled.

Cc: Tony Luck <tony.luck@intel.com>
Tested-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

arch/ia64/kernel/process.c

@@ -662,7 +662,7 @@ void
 machine_restart (char *restart_cmd)
 {
 	(void) notify_die(DIE_MACHINE_RESTART, restart_cmd, NULL, 0, 0, 0);
-	(*efi.reset_system)(EFI_RESET_WARM, 0, 0, NULL);
+	efi_reboot(REBOOT_WARM, NULL);
 }
 
 void

arch/x86/kernel/reboot.c

@@ -528,11 +528,7 @@ static void native_machine_emergency_restart(void)
 			break;
 
 		case BOOT_EFI:
-			if (efi_enabled(EFI_RUNTIME_SERVICES))
-				efi.reset_system(reboot_mode == REBOOT_WARM ?
-						 EFI_RESET_WARM :
-						 EFI_RESET_COLD,
-						 EFI_SUCCESS, 0, NULL);
+			efi_reboot(reboot_mode, NULL);
 			reboot_type = BOOT_BIOS;
 			break;
 

drivers/firmware/efi/Makefile

 #
 # Makefile for linux kernel
 #
-obj-$(CONFIG_EFI)			+= efi.o vars.o
+obj-$(CONFIG_EFI)			+= efi.o vars.o reboot.o
 obj-$(CONFIG_EFI_VARS)			+= efivars.o
 obj-$(CONFIG_EFI_VARS_PSTORE)		+= efi-pstore.o
 obj-$(CONFIG_UEFI_CPER)			+= cper.o

drivers/firmware/efi/reboot.c

+/*
+ * 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>
+
+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;
+	}
+
+	efi.reset_system(efi_mode, EFI_SUCCESS, 0, NULL);
+}

include/linux/efi.h

@@ -20,6 +20,7 @@
 #include <linux/ioport.h>
 #include <linux/pfn.h>
 #include <linux/pstore.h>
+#include <linux/reboot.h>
 
 #include <asm/page.h>
 
@@ -928,11 +929,14 @@ static inline bool efi_enabled(int feature)
 {
 	return test_bit(feature, &efi.flags) != 0;
 }
+extern void efi_reboot(enum reboot_mode reboot_mode, const char *__unused);
 #else
 static inline bool efi_enabled(int feature)
 {
 	return false;
 }
+static inline void
+efi_reboot(enum reboot_mode reboot_mode, const char *__unused) {}
 #endif
 
 /*