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References: <20211204174156.977245-1-arnd@kernel.org>
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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Sat, 4 Dec 2021 18:55:07 +0100
Message-ID: <CAMj1kXGj=AGp6im71+OETHGSCat0mQfOf7FcDdyKwxFEBubzdw@mail.gmail.com>
Subject: Re: [PATCH] x86/efi: select ARCH_USE_MEMREMAP_PROT
To:     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>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        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>
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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.

> ---
>  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
>