[PATCH 5.5 097/170] x86/ioremap: Fix CONFIG_EFI=n build

[Greg Kroah-Hartman]

From: Borislav Petkov <bp@xxxxxxx>

commit 870b4333a62e45b0b2000d14b301b7b8b8cad9da upstream.

In order to use efi_mem_type(), one needs CONFIG_EFI enabled. Otherwise
that function is undefined. Use IS_ENABLED() to check and avoid the
ifdeffery as the compiler optimizes away the following unreachable code
then.

Fixes: 985e537a4082 ("x86/ioremap: Map EFI runtime services data as encrypted for SEV")
Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Tested-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/7561e981-0d9b-d62c-0ef2-ce6007aff1ab@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/x86/mm/ioremap.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -115,6 +115,9 @@ static void __ioremap_check_other(resour
 	if (!sev_active())
 		return;
 
+	if (!IS_ENABLED(CONFIG_EFI))
+		return;
+
 	if (efi_mem_type(addr) == EFI_RUNTIME_SERVICES_DATA)
 		desc->flags |= IORES_MAP_ENCRYPTED;
 }