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

[Song Shuai]

Sorry for the delayed reply,
My tinylab email went something wrong, I'll use gmail in this thread.

在 2023/6/25 22:18, Conor Dooley 写道:
> 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.

At this time, OpenSbi [v0.8,v1.3) and edk2(RiscVVirt) indeed don't obey 
the DT/UEFI spec. This statement is excerpted from "Reserved memory for 
resident firmware" part from the upcoming riscv/boot.rst. It isn't 
accurate for now. How about deleting this one?

Actually with 3335068f8721 reverted, the change of MIN_MEMBLOCK_ADDR can 
avoid the mapping of firmware memory, I will make it clear in the next 
version.

> > 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@xxxxxxxxxxx>
> > ---
> >   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