Re: [PATCH 1/3] arm64: Add late jump to kernel board hook

Tom Rini
2025-01-15T01:13:59Z

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On Sun, Jan 12, 2025 at 11:36:57PM +0100, Marek Vasut wrote:

> Add empty weak assembler function armv8_switch_to_el2_prep() which is
> jumped to just before U-Boot determines which EL it is running in and
> decides which path to take to boot the Linux kernel.
>
> This weak function is meant to be used by architecture specific code
> to implement jump to a firmware blob, which then returns right past
> this weak function and continues execution of U-Boot code which then
> boots the Linux kernel. One example of such use case is when U-Boot
> jump tp TFA BL31, which switches from EL3 to EL2 and then returns to
> U-Boot code newly running in EL2 and starts the Linux kernel.
>
> The weak function is called with caches already disabled and DM shut
> down. Any preparatory work or even loading of more data must be done
> in board_prep_linux(), this hook is meant only for the final jump to
> the firmware and return to U-Boot before booting Linux.
>
> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>

Reviewed-by: Tom Rini <trini@konsulko.com>

--
Tom

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