[PATCH 03/16] image: Take entry point as an output of setup_booti

[Jiaxun Yang]

在2024年6月11日六月 下午2:52，Tom Rini写道：
> On Tue, Jun 11, 2024 at 02:29:38PM +0100, Jiaxun Yang wrote:
>> 
>> 
>> 在2024年6月11日六月 下午2:02，Heinrich Schuchardt写道：
>> > On 22.05.24 17:34, Jiaxun Yang wrote:
>> >> For LoongArch the start of the image is not the entry
>> >> point to the image.
>> >
>> > Looking at arch/loongarch/kernel/head.S there seem to be two cases:
>> >
>> > * The kernel has an EFI stub (CONFIG_EFI_STUB=y).
>> >    The legacy physical entry point is available at offset 0x08 of the
>> > header.
>> > * The kernel has no EFI stub.
>> >    The kernel entry point matches the start of the image.
>> >
>> > Where do you differentiate between the cases?
>> 
>> Hi Heinrich,
>> 
>> In case there is no EFI stub LoongArch would use elf format vmlinux, there
>> is no real "raw" image for us.
>> 
>> bootelf can't be used at the moment as it doesn't setup FDT and other environments
>> properly.
>> 
>> I'm planning to implement a bootlinuxelf command for this case, as MIPS, LoongArch,
>> xtensa are all using ELF as default kernel image format.
>
> Please note that we have CONFIG_CMD_ELF_FDT_SETUP already, so adjusting
> things so that bootelf works for this case should be doable without a
> new command.

This is a little bit broken as then you'll need to bring architecture specific
functions to bootelf to setup boot registers, initrd etc. It's fine for Arm64 which
you just need to throw fdt into a location in memory but for MIPS and LoongArch 
you have to setup a good deal of other stuff.

Ideally those setups should be done with bootm_run_states as what we've done at
booti, but that would be a semantic to bootelf command. I know many existing
MIPS bare-metal applications rely on argc/argv style bootelf and I don't want to
break them, thus I think a new command is necessary.

Thanks
>
> -- 
> Tom
>
> 附件:
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-- 
- Jiaxun