Re: [PATCH V4 mm-hotfixes 2/3] mm: introduce and use {pgd,p4d}_populate_kernel()

Lorenzo Stoakes
2025-08-12T16:09:14Z

On Tue, Aug 12, 2025 at 06:53:49PM +0900, Harry Yoo wrote:
> > I'd add that arm handles PGTBL_PMD_MODIFIED and therefore remains unaffected
> > just to be super clear.
>
> Will do:
>
> This change currently targets only x86_64, so only PGD and P4D level
> helpers are introduced. Currently, these helpers are no-ops since no
> architecture sets PGTBL_{PGD,P4D}_MODIFIED in ARCH_PAGE_TABLE_SYNC_MASK.
>
> In theory, PUD and PMD level helpers can be added later if needed by
> other architectures. For now, 32-bit architectures (x86-32 and arm)
> only handle PGTBL_PMD_MODIFIED, so p*d_populate_kernel() will never
> affect them unless we introduce a PMD level helper.

Sounds good!

Cheers, Lorenzo