[RFC] Expected behavior of the go command

[Simon Glass]

Hi Anshul,

On Wed, 23 Apr 2025 at 04:04, Anshul Dalal <anshuld at ti.com> wrote:
>
> Hi all,
>
> I was trying to understand how the go command is expected to work when
> used to load custom OSes. My use case requires getting a proprietary OS
> to boot using the go command on a TI K3 platform. The OS expects caches
> to be flushed and the mmu to be disabled before we jump to it.
>
> The go command (do_go func in cmd/boot.c) calls the do_go_exec function
> underneath which does not seem to have a consistent implementation
> across various architectures.
>
> In RISC-V the implementation (arch/riscv/lib/boot.c:10) calls
> cleanup_before_linux before jumping to the loaded binary. This behaviour
> would enable the direct use of the go command for booting a custom OS
> (like in my use case). Though no such generic implementation exists for
> ARM64.
>
> I was wondering why we have the call to cleanup_before_linux for RISCV
> and not ARM64?
>
> Also, is booting a custom OS using the go command a supported use-case?
> If yes, it might be better to rename the function to be more generic
> like cleanup_before_os from *_linux and call it for each invocation of
> the go command.

Yes it is supposed to do what you say. You could rationalise the code
a bit, so that all archs do a similar thing, or perhaps just RISC-V
and ARM for now.

Regards,
Simon