[v2] Documentation: Fix x86_64 UEFI outdated references to elilo

[PATCH v2] Documentation: Fix x86_64 UEFI outdated references to elilo

Posted by Nir Lichtman 11 months, 2 weeks ago

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>
---

v2: Fix list not rendered properly and minor wording fixes (thanks for the CR Bagas)
Also fix to use shorter lines

 Documentation/arch/x86/x86_64/uefi.rst | 36 +++++++++++++++++++-------
 1 file changed, 26 insertions(+), 10 deletions(-)

diff --git a/Documentation/arch/x86/x86_64/uefi.rst b/Documentation/arch/x86/x86_64/uefi.rst
index fbc30c9a071d..3949d83a9915 100644
--- a/Documentation/arch/x86/x86_64/uefi.rst
+++ b/Documentation/arch/x86/x86_64/uefi.rst
@@ -12,14 +12,19 @@ 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> to learn how to use the EFI stub.
+
+Below are general EFI setup guidelines on the x86_64 platform,
+regardless of whether you use the EFI stub or a separate bootloader.
+
 - Build the kernel with the following configuration::
 
 	CONFIG_FB_EFI=y
@@ -31,16 +36,27 @@ 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>
+
+- Copy the boot files to the VFAT partition:
+    If you use the EFI stub method, the kernel acts also as an EFI executable.
+
+    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.
 
-	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.
+    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

Re: [PATCH v2] Documentation: Fix x86_64 UEFI outdated references to elilo

Posted by Jonathan Corbet 11 months, 1 week ago

Nir Lichtman <nir@lichtman.org> writes:

> 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>
> ---

I've applied this, but ...

> v2: Fix list not rendered properly and minor wording fixes (thanks for the CR Bagas)
> Also fix to use shorter lines
>
>  Documentation/arch/x86/x86_64/uefi.rst | 36 +++++++++++++++++++-------
>  1 file changed, 26 insertions(+), 10 deletions(-)
>
> diff --git a/Documentation/arch/x86/x86_64/uefi.rst b/Documentation/arch/x86/x86_64/uefi.rst
> index fbc30c9a071d..3949d83a9915 100644
> --- a/Documentation/arch/x86/x86_64/uefi.rst
> +++ b/Documentation/arch/x86/x86_64/uefi.rst
> @@ -12,14 +12,19 @@ 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.
>  

...I did take the liberty of wrapping the above line to fit within 80
columns.

Thanks,

jon

Re: [PATCH v2] Documentation: Fix x86_64 UEFI outdated references to elilo

Posted by Bagas Sanjaya 11 months, 1 week ago

On Wed, Jan 08, 2025 at 11:35:22AM +0000, Nir Lichtman wrote:
> diff --git a/Documentation/arch/x86/x86_64/uefi.rst b/Documentation/arch/x86/x86_64/uefi.rst
> index fbc30c9a071d..3949d83a9915 100644
> --- a/Documentation/arch/x86/x86_64/uefi.rst
> +++ b/Documentation/arch/x86/x86_64/uefi.rst
> @@ -12,14 +12,19 @@ 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> to learn how to use the EFI stub.
> +
> +Below are general EFI setup guidelines on the x86_64 platform,
> +regardless of whether you use the EFI stub or a separate bootloader.
> +
>  - Build the kernel with the following configuration::
>  
>  	CONFIG_FB_EFI=y
> @@ -31,16 +36,27 @@ 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>
> +
> +- Copy the boot files to the VFAT partition:
> +    If you use the EFI stub method, the kernel acts also as an EFI executable.
> +
> +    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.
>  
> -	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.
> +    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.

Looks good, thanks!

Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>

-- 
An old man doll... just what I always wanted! - Clara

Re: [PATCH v2] Documentation: Fix x86_64 UEFI outdated references to elilo

Posted by Nir Lichtman 11 months, 1 week ago

On Mon, Jan 13, 2025 at 04:59:00PM +0700, Bagas Sanjaya wrote:
> On Wed, Jan 08, 2025 at 11:35:22AM +0000, Nir Lichtman wrote:
> > diff --git a/Documentation/arch/x86/x86_64/uefi.rst b/Documentation/arch/x86/x86_64/uefi.rst
> > index fbc30c9a071d..3949d83a9915 100644
> > --- a/Documentation/arch/x86/x86_64/uefi.rst
> > +++ b/Documentation/arch/x86/x86_64/uefi.rst
> > @@ -12,14 +12,19 @@ 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.
> >  
[..]
> >  - 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.
> 
> Looks good, thanks!
> 
> Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>

Thanks for the review! Small question:
I noticed that there is also a script in the kernel (genimage) which enables
automation of building the image, including an image utilizing the EFI stub.
The EFI stub image can be built by enabling the relavent EFI stub config options
and then running "make hdimage", thing is that I couldn't get the script the to
work yet (stuck on an error about missing EDK2/OMVF), but I could look deeper into
this method as well and add it also to this doc, do you think it is also relavent?

Thanks,
Nir