On Thu, Nov 16, 2023 at 6:15 PM Heinrich Schuchardt heinrich.schuchardt@canonical.com wrote:
On 11/16/23 17:52, Shantur Rathore wrote:
Hi Simon,
Currently bootstd - bootmethod_efi only looks for the default bootxx64.efi in /EFI/boot folder only. Generally many distros end up putting their bootloaders in EFI/<distro> folders like EFI/ubuntu and EFI/debian etc.
In x86 worlds, the NVRAM is modified and new boot entries are added to support these but in the U-boot world the NVRAM variables are read-only.
I guess you are referring to UEFI boot options. These typically are not stored in non-volatile RAM but on a SPI flash device.
Thanks for correcting me.
What would be the best way to implement this?
I was thinking of having a "efi_prefixes" environment variable which can be set to "ubuntu debian centos" etc and bootmethod_efi can try all of them. Will bootmethod_efi be able to support multiple entries ( thinking of multiboot ) ?
On my laptop I have:
EFI/Microsoft/Boot/bootmgr.efi EFI/Microsoft/Boot/memtest.efi EFI/Boot/bootx64.efi EFI/Boot/fbx64.efi EFI/Boot/mmx64.efi EFI/debian/shimx64.efi EFI/debian/grubx64.efi EFI/debian/mmx64.efi EFI/debian/fbx64.efi EFI/ubuntu/grubx64.efi EFI/ubuntu/shimx64.efi EFI/ubuntu/mmx64.efi
Obviously each installed operating system provides multiple EFI binaries and non uses the fallback file name BOOT<ARCH>.EFI. A value "ubuntu debian centos" would not be able to describe which file you are looking for.
We already have the U-Boot command line eficonfig and efidebug commands to set up UEFI boot options which can describe which EFI binary to load and which command line to pass to it. These are considered by the existing boot flows.
So, I am building a new RockPro64 based cluster and using Canonical MAAS to set them up automatically, booting them up using DHCP and installing them over the network. I configured an Armbian image using Packer to be compatible with MAAS and it happily installs it. As part of installation process, a grub-install is run which installs the grub efi, this EFI ends up in EFI/debian instead of expected EFI/boot. To be able to make it boot, I have to add commands to move it to EFI/boot. I am trying to find a way in U-Boot that would allow me to skip this step. With eficonfig if I understand correctly, it would need manual intervention to create boot entries.
If you are installing the shim-signed package on Ubuntu, the EFI boot option for Ubuntu is set up by EFI/BOOT/BOOT<ARCH>.EFI using the content of EFI/ubuntu/BOOT<ARCH>.CSV. This is done before ExitBootServices() and therefore should work with current U-Boot.
Patches are pending upstream to make EFI variables writable from Linux if they are stored in the RPMB partition in the eMMC. See this series:
https://lore.kernel.org/linux-efi/20231107054057.1893-2-masahisa.kojima@lina...
Would it be possible to save it in SPI Flash as the U-Boot environment ?
Kind regards, Shantur
Best regards
Heinrich