[PATCH V1 1/3] Revert "RISC-V: mark hibernation as nonportable"

[Conor Dooley]

On Sun, Jun 25, 2023 at 10:09:29PM +0800, Song Shuai wrote:
> This reverts commit ed309ce522185583b163bd0c74f0d9f299fe1826.
> 
> With the commit 3335068f8721 ("riscv: Use PUD/P4D/PGD pages for the
> linear mapping") reverted, the MIN_MEMBLOCK_ADDR points the kernel
> load address which was placed at a PMD boundary.

> And firmware always
> correctly mark resident memory, or memory protected with PMP as
> per the devicetree specification and/or the UEFI specification.

But this is not true? The versions of OpenSBI that you mention in your
cover letter do not do this.
Please explain.

> So those regions will not be mapped in the linear mapping and they
> can be safely saved/restored by hibernation.
> 
> Signed-off-by: Song Shuai <songshuaishuai at tinylab.org>
> ---
>  arch/riscv/Kconfig | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 5966ad97c30c..17b5fc7f54d4 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -800,11 +800,8 @@ menu "Power management options"
>  
>  source "kernel/power/Kconfig"
>  
> -# Hibernation is only possible on systems where the SBI implementation has
> -# marked its reserved memory as not accessible from, or does not run
> -# from the same memory as, Linux
>  config ARCH_HIBERNATION_POSSIBLE
> -	def_bool NONPORTABLE
> +	def_bool y
>  
>  config ARCH_HIBERNATION_HEADER
>  	def_bool HIBERNATION
> -- 
> 2.20.1
> 
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