Re: [PATCH v3 17/17] efi: x86: Make the deprecated EFI handover protocol optional

From: Randy Dunlap <rdunlap@infradead.org>
To: Ard Biesheuvel <ardb@kernel.org>, linux-efi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Michael Roth <michael.roth@amd.com>
Subject: Re: [PATCH v3 17/17] efi: x86: Make the deprecated EFI handover protocol optional
Date: Tue, 22 Nov 2022 10:56:50 -0800	[thread overview]
Message-ID: <0cf1d78a-8781-e31e-00a3-3ca68af5a025@infradead.org> (raw)
In-Reply-To: <20221122161017.2426828-18-ardb@kernel.org>


On 11/22/22 08:10, Ard Biesheuvel wrote:
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 8c6da5e42d5a6c25..121f1fdca3145fd2 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -1981,6 +1981,23 @@ config EFI_STUB
>  
>  	  See Documentation/admin-guide/efi-stub.rst for more information.
>  
> +config EFI_HANDOVER_PROTOCOL
> +	bool "EFI handover protocol (DEPRECATED)"
> +	depends on EFI_STUB
> +	default y
> +	help
> +	  Select this in order to include support for the deprecated EFI
> +	  handover protocol, which defines alternative entry points into the
> +	  EFI stub.  This is a practice that has no basis in the UEFI
> +	  specification, and requires a priori knowledge on the part of the
> +	  bootloader about Linux/x86 specific ways of passing the command line
> +	  and initrd, and where in memory those assets may be loaded.
> +
> +	  If in doubt, say Y. Even though he corresponding support is not

	                                  the

> +	  present in upstream GRUB or other bootloaders, most distros build
> +	  GRUB with numerous downstream patches applied, and may rely on the
> +	  handover protocol as as result.

-- 
~Randy