efi: Add EFI_SECURE_BOOT bit

BugLink: http://bugs.launchpad.net/bugs/1566221

UEFI machines can be booted in Secure Boot mode.  Add a EFI_SECURE_BOOT bit
for use with efi_enabled.
Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

arch/x86/kernel/setup.c

@@ -1145,7 +1145,9 @@ void __init setup_arch(char **cmdline_p)
 
 #ifdef CONFIG_EFI_SECURE_BOOT_SIG_ENFORCE
 	if (boot_params.secure_boot) {
+		set_bit(EFI_SECURE_BOOT, &efi.flags);
 		enforce_signed_modules();
+		pr_info("Secure boot enabled\n");
 	}
 #endif
 

include/linux/efi.h

@@ -980,6 +980,7 @@ extern int __init efi_setup_pcdp_console(char *);
 #define EFI_ARCH_1		7	/* First arch-specific bit */
 #define EFI_DBG			8	/* Print additional debug info at runtime */
 #define EFI_NX_PE_DATA		9	/* Can runtime data regions be mapped non-executable? */
+#define EFI_SECURE_BOOT		10	/* Are we in Secure Boot mode? */
 
 #ifdef CONFIG_EFI
 /*