On Fri, 26 Sep 2025 08:42:35 +1000 Andrew Donnellan <a...@linux.ibm.com> wrote:
> On Tue, 2025-09-09 at 19:13 +1000, Andrew Donnellan wrote:
> > Support page table check on all PowerPC platforms. This works by serialising
> > assignments, reassignments and clears of page table entries at each level in
> > order to ensure that anonymous mappings have at most one writable consumer,
> > and likewise that file-backed mappings are not simultaneously also anonymous
> > mappings.
> >
> > In order to support this infrastructure, a number of helpers or stubs must
> > be
> > defined or updated for all powerpc platforms. Additionally, we separate
> > set_pte_at() and set_pte_at_unchecked(), to allow for internal,
> > uninstrumented
> > mappings.
> >
> > On some PowerPC platforms, implementing {pte,pmd,pud}_user_accessible_page()
> > requires the address. We revert previous changes that removed the address
> > parameter from various interfaces, and add it to some other interfaces,
> > in order to allow this.
> >
> > Note that on 32 bit systems with CONFIG_KFENCE=y, you need [0] to avoid
> > possible failures in init code (this is a code patching/static keys issue,
> > which was discovered by a user testing this series but isn't a bug in page
> > table check).
> >
> > (This series was initially written by Rohan McLure, who has left IBM and
> > is no longer working on powerpc.)
>
> Is this likely to make it in in time for 6.18, or should I respin it post
> merge
> window?
The latter, please.
