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

[Randy Dunlap]

On 3/18/20 11:34 AM, Borislav Petkov wrote:
> 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@xxxxxxx>
> 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@xxxxxxxxxxxxx>
> Signed-off-by: Borislav Petkov <bp@xxxxxxx>
> Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
> Link: https://lkml.kernel.org/r/7561e981-0d9b-d62c-0ef2-ce6007aff1ab@xxxxxxxxxxxxx

Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> # build-tested

Thanks.

> ---
>  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;
>  }
> 


-- 
~Randy