Re: [PATCH V1 0/3] Revert huge-paged linear mapping and its related fixups

[Conor Dooley]

On Sun, Jun 25, 2023 at 10:09:28PM +0800, Song Shuai wrote:
> We have encountered these two issues about huge-paged linear mapping since v6.4-rc1: 
> 
> 1. Bug report: kernel paniced when system hibernates[1]
>   
> OpenSbi [v0.8,v1.3) set the PMP regions as !no-map, and the commit 3335068f8721 
> ("riscv: Use PUD/P4D/PGD pages for the linear mapping") mapped them in linear mapping.
> The hibernation process attempted to save/restore these mapped regions resulting in access fault.
> 
> This issue was temporarily fixed by commit ed309ce52218 ("RISC-V: mark hibernation as nonportable").
> But as Alex's RFC and Rob's response stats in another thread [2] , 
> "Hibernation is only one case. Speculative accesses could also occur."
> So this fixing commit seems not the perfect answer to this issue.

This is a misunderstanding, I was not attempting to fix the issue, but
rather buy time to fix the problem properly, without regressing support
for hibernation when we do.

Cheers,
Conor.

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