Re: [PATCH] Documentation: Fix x86_64 UEFI outdated references to elilo

[Nir Lichtman <nir@lichtman.org>]

On Mon, Jan 06, 2025 at 10:35:27PM +0000, Nir Lichtman wrote:
> Problem: The x86_64 UEFI doc references Elilo which is an
> unmaintained/orphaned bootloader project. Also, on x86_64 a bootloader
> is technically not actually required since there is support for the
> Linux EFI stub.
> 
> Solution: Remove the references to Elilo from the doc and refer to the
> EFI stub doc page, update steps accordingly, and add more details about
> creation of the EFI partition to improve clarity.
> 
> Signed-off-by: Nir Lichtman <nir@lichtman.org>
> ---

Adding also the x86 arch maintainers to the thread (forgot).

>  Documentation/arch/x86/x86_64/uefi.rst | 26 ++++++++++++++++----------
>  1 file changed, 16 insertions(+), 10 deletions(-)
> 
> diff --git a/Documentation/arch/x86/x86_64/uefi.rst b/Documentation/arch/x86/x86_64/uefi.rst
> index fbc30c9a071d..c056063f49d5 100644
> --- a/Documentation/arch/x86/x86_64/uefi.rst
> +++ b/Documentation/arch/x86/x86_64/uefi.rst
> @@ -12,14 +12,16 @@ with EFI firmware and specifications are listed below.
>  
>  1. UEFI specification:  http://www.uefi.org
>  
> -2. Booting Linux kernel on UEFI x86_64 platform requires bootloader
> -   support. Elilo with x86_64 support can be used.
> +2. Booting Linux kernel on UEFI x86_64 platform can either be
> +   done using the <Documentation/admin-guide/efi-stub.rst> or using a separate bootloader.
>  
>  3. x86_64 platform with EFI/UEFI firmware.
>  
>  Mechanics
>  ---------
>  
> +Refer to <Documentation/admin-guide/efi-stub.rst> for general setup guidelines on usage of the EFI stub, the following are setup specifics for EFI in general on the x86_64 platform.
> +
>  - Build the kernel with the following configuration::
>  
>  	CONFIG_FB_EFI=y
> @@ -31,16 +33,20 @@ Mechanics
>  	CONFIG_EFI=y
>  	CONFIG_EFIVAR_FS=y or m		# optional
>  
> -- Create a VFAT partition on the disk
> -- Copy the following to the VFAT partition:
> +- Create a VFAT partition on the disk with the EFI System flag
> +    You can do this with fdisk with the following commands:
> +    1. g - initialize a GPT partition table
> +    2. n - create a new partition
> +    3. t - change the partition type to "EFI System" (number 1)
> +    4. w - write and save the changes
> +    Afterwards, initialize the VFAT filesystem by running mkfs::
> +
> +        mkfs.fat /dev/<your-partition>
>  
> -	elilo bootloader with x86_64 support, elilo configuration file,
> -	kernel image built in first step and corresponding
> -	initrd. Instructions on building elilo and its dependencies
> -	can be found in the elilo sourceforge project.
> +- Copy the boot files to the VFAT partition:
> +    If you use the EFI stub method, the kernel acts also as an EFI executable, and you can just copy the bzImage to the EFI/boot/bootx64.efi path on the partition so that it will automatically get booted, see the <Documentation/admin-guide/efi-stub.rst> page for additional instructions regarding passage of kernel parameters and initramfs.
> +    If you use a custom bootloader, refer to the relevant documentation for help on this part.
>  
> -- Boot to EFI shell and invoke elilo choosing the kernel image built
> -  in first step.
>  - If some or all EFI runtime services don't work, you can try following
>    kernel command line parameters to turn off some or all EFI runtime
>    services.
> -- 
> 2.39.5
>