Subject: Re: [PATCH] x86/efi: select ARCH_USE_MEMREMAP_PROT
To:     Ard Biesheuvel <ardb@kernel.org>, Arnd Bergmann <arnd@kernel.org>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        X86 ML <x86@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>,
        Anshuman Khandual <anshuman.khandual@arm.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
References: <20211204174156.977245-1-arnd@kernel.org>
 <CAMj1kXGj=AGp6im71+OETHGSCat0mQfOf7FcDdyKwxFEBubzdw@mail.gmail.com>
From:   Tom Lendacky <thomas.lendacky@amd.com>
Message-ID: <120102a7-3c03-ce36-198c-f60f059a6cf9@amd.com>
Date:   Sun, 5 Dec 2021 09:15:15 -0600
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On 12/4/21 11:55 AM, Ard Biesheuvel wrote:
> On Sat, 4 Dec 2021 at 18:42, Arnd Bergmann <arnd@kernel.org> wrote:
>>
>> From: Arnd Bergmann <arnd@arndb.de>
>>
>> The patch to map the EFI memmap as encrypted introduces a
>> link failure in configurations without encryption support:
>>
>> x86_64-linux-ld: arch/x86/platform/efi/quirks.o: in function `efi_arch_mem_reserve':
>> quirks.c:(.init.text+0x127): undefined reference to `early_memremap_prot'
>>
>> Select the necessary symbol here as well to fix the build.
>>
>> Fixes: 8f1dd76c9b55 ("x86/sme: Explicitly map new EFI memmap table as encrypted")
>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> 
> Thanks for the report. I'll fold this fix into the original patch instead.

Thanks Arnd and Ard!

Tom

> 
>> ---
>>   arch/x86/Kconfig | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
>> index 05362527f6b5..93befe25d787 100644
>> --- a/arch/x86/Kconfig
>> +++ b/arch/x86/Kconfig
>> @@ -1934,6 +1934,7 @@ config EFI
>>          depends on ACPI
>>          select UCS2_STRING
>>          select EFI_RUNTIME_WRAPPERS
>> +       select ARCH_USE_MEMREMAP_PROT
>>          help
>>            This enables the kernel to use EFI runtime services that are
>>            available (such as the EFI variable services).
>> --
>> 2.29.2
>>