efi: Add kernel param efi=noruntime

noefi kernel param means actually disabling efi runtime, Per suggestion
from Leif Lindholm efi=noruntime should be better. But since noefi is
already used in X86 thus just adding another param efi=noruntime for
same purpose.
Signed-off-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

Documentation/kernel-parameters.txt

@@ -992,13 +992,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			Format: {"off" | "on" | "skip[mbr]"}
 
 	efi=		[EFI]
-			Format: { "old_map", "nochunk" }
+			Format: { "old_map", "nochunk", "noruntime" }
 			old_map [X86-64]: switch to the old ioremap-based EFI
 			runtime services mapping. 32-bit still uses this one by
 			default.
 			nochunk: disable reading files in "chunks" in the EFI
 			boot stub, as chunking can cause problems with some
 			firmware implementations.
+			noruntime : disable EFI runtime services support
 
 	efi_no_storage_paranoia [EFI; X86]
 			Using this parameter you can use more than 50% of

arch/x86/platform/efi/efi.c

@@ -930,11 +930,11 @@ u64 efi_mem_attributes(unsigned long phys_addr)
 	return 0;
 }
 
-static int __init parse_efi_cmdline(char *str)
+static int __init arch_parse_efi_cmdline(char *str)
 {
 	if (parse_option_str(str, "old_map"))
 		set_bit(EFI_OLD_MEMMAP, &efi.flags);
 
 	return 0;
 }
-early_param("efi", parse_efi_cmdline);
+early_param("efi", arch_parse_efi_cmdline);

drivers/firmware/efi/efi.c

@@ -54,6 +54,15 @@ bool efi_runtime_disabled(void)
 	return disable_runtime;
 }
 
+static int __init parse_efi_cmdline(char *str)
+{
+	if (parse_option_str(str, "noruntime"))
+		disable_runtime = true;
+
+	return 0;
+}
+early_param("efi", parse_efi_cmdline);
+
 static struct kobject *efi_kobj;
 static struct kobject *efivars_kobj;