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; }