Re: [PATCH v2] Revert "mm/pgtable: add stubs for {pmd/pub}_{set/clear}_huge"

Will Deacon [off-list ref] writes:

On Wed, 21 Jul 2021 17:02:13 +1000, Michael Ellerman wrote:

quoted

This reverts commit c742199a014de23ee92055c2473d91fe5561ffdf.

c742199a014d ("mm/pgtable: add stubs for {pmd/pub}_{set/clear}_huge")
breaks arm64 in at least two ways for configurations where PUD or PMD
folding occur:

  1. We no longer install huge-vmap mappings and silently fall back to
     page-granular entries, despite being able to install block entries
     at what is effectively the PGD level.

[...]

Thank you Michael! I owe you a beer next time I see you, if we don't go
extinct before then.

No worries, thanks to Christophe for identifying the solution while on
vacation!

Beers seem a long way off, but hopefully one day :)

cheers