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

[Borislav Petkov <bp@alien8.de>]

On Wed, Mar 18, 2020 at 04:17:07PM +0100, Borislav Petkov wrote:
> > ld: arch/x86/mm/ioremap.o: in function `__ioremap_caller':
> > ioremap.c:(.text+0x150): undefined reference to `efi_mem_type'
> 
> Working on it.

The below should fix it:

---
From: Borislav Petkov <bp@suse.de>
Date: Wed, 18 Mar 2020 19:27:48 +0100

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@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lkml.kernel.org/r/7561e981-0d9b-d62c-0ef2-ce6007aff1ab@infradead.org
---
 arch/x86/mm/ioremap.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 935a91e1fd77..18c637c0dc6f 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -115,6 +115,9 @@ static void __ioremap_check_other(resource_size_t addr, struct ioremap_desc *des
 	if (!sev_active())
 		return;
 
+	if (!IS_ENABLED(CONFIG_EFI))
+		return;
+
 	if (efi_mem_type(addr) == EFI_RUNTIME_SERVICES_DATA)
 		desc->flags |= IORES_MAP_ENCRYPTED;
 }
-- 
2.21.0

-- 
Regards/Gruss,
    Boris.

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