Hello,
Sorry for the delay. Thank you for the replies.
On Tue, Mar 8, 2022 at 9:39 PM Simon Glass sjg@chromium.org wrote:
Hi,
On Tue, 8 Mar 2022 at 06:57, Heinrich Schuchardt xypron.glpk@gmx.de
wrote:
On 3/8/22 13:59, Ahamed Husni wrote:
Hi everyone,
I am trying to work on a project to port the U-Boot UEFI code to
coreboot
as a payload. I haven't worked with UEFI before except running a basic EFI payload
in a
coreboot/u-boot environment. (Serial output: https://gist.github.com/drac98/6166d29f6c3a2baf2f4e791925ea98d3)
I would like to know how UEFI is implemented in U-Boot. Is UEFI
integrated
into u-boot or is it implemented like a payload?
Hello Ahamed,
the UEFI API implementation is an integral part of U-Boot.
Where is the UEFI source code? Is it the following files in the tree https://source.denx.de/u-boot/custodians/u-boot-efi lib/ |__ efi/ |__ efi_driver/ |__ efi_loader/
U-Boot can both be run on top of UEFI. This is the code you find in /lib/efi/. Furthermore UEFI can run as a firmware providing the UEFI API. This is what you find in /lib/efi_loader/ and /lib/efi_driver/.
Then I should look at the lib/efi_loader/ and lib/efi_driver/ I guess. Thank you!
You can build U-Boot as payload for coreboot which offers the UEFI API implementation. See configs/coreboot64_defconfig.
U-Boot runs ARM and RISC-V Linux successfully via UEFI.
What architecture are you looking at?
I'll be mostly working with a x86_64 QEMU target. I am proposing this project for the GSoC this year. So the architecture could change after discussions.
Simon (on CC) has been working on U-Boot on UEFI and Coreboot while I have concentrated on the UEFI API implementation in U-Boot.
@Simon can I CC you to the discussion in coreboot?
Yes you can use U-Boot as a coreboot payload - this is now running in CI so we make sure it works on each release. I plan to add more test cases to it but have been waiting to see if coreboot can add something similar to its CI.
I used U-Boot (v2019.4) as a coreboot payload to run my hello world EFI payload and it worked.
I also tried different combinations of the applications, | Arch | U-Boot | EFI | Status | |--------|---------|--------|-------------| | 32bit | 32bit | 32bit | Success | | 64bit | 32bit | 32bit | Success | | 64bit | 64bit | 64bit | Fails and reboot | | 64bit | 64bit | 32bit | Fails and returns back to shell printing the error code | | 64bit | 32bit | 64bit | Fails and returns back to shell printing the error code |
The last two fail because the EFI does not support booting a 64-bit application from a 32-bit EFI (or vice versa) as mentioned in the u-boot docs. Is this something in the UEFI specification?
The third one fails because 64-bit EFI is not supported yet.
Is there a way to run 64-bit EFI with something like the 32-bit SPL binary used to boot 64-bit u-boot in coreboot(32-bit)? Ex: can we boot a 64bit Windows/Linux with 32-bit EFI? It seems linux can work with 32bit EFI from this https://github.com/maharmstone/quibble/issues/2 thread.
Best Regards, Husni Faiz.
+Stefan Reinauer as we have been talking about this
It seems better to go that way than trying to duplicate efforts. We have a program now to move UEFI to use driver model properly, for example.
Regards, Simon