Messages in this thread | | | Date | Mon, 20 Feb 2023 12:19:41 +0100 | Subject | Re: [PATCH v6 11/41] mm: Introduce pte_mkwrite_kernel() | From | David Hildenbrand <> |
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On 18.02.23 22:14, Rick Edgecombe wrote: > The x86 Control-flow Enforcement Technology (CET) feature includes a new > type of memory called shadow stack. This shadow stack memory has some > unusual properties, which requires some core mm changes to function > properly. > > One of these changes is to allow for pte_mkwrite() to create different > types of writable memory (the existing conventionally writable type and > also the new shadow stack type). Future patches will convert pte_mkwrite() > to take a VMA in order to facilitate this, however there are places in the > kernel where pte_mkwrite() is called outside of the context of a VMA. > These are for kernel memory. So create a new variant called > pte_mkwrite_kernel() and switch the kernel users over to it. Have > pte_mkwrite() and pte_mkwrite_kernel() be the same for now. Future patches > will introduce changes to make pte_mkwrite() take a VMA. > > Only do this for architectures that need it because they call pte_mkwrite() > in arch code without an associated VMA. Since it will only currently be > used in arch code, so do not include it in arch_pgtable_helpers.rst. > > Cc: linux-doc@vger.kernel.org > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-s390@vger.kernel.org > Cc: xen-devel@lists.xenproject.org > Cc: linux-arch@vger.kernel.org > Cc: linux-mm@kvack.org > Tested-by: Pengfei Xu <pengfei.xu@intel.com> > Suggested-by: David Hildenbrand <david@redhat.com> > Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> >
Acked-by: David Hildenbrand <david@redhat.com>
Do we also have to care about pmd_mkwrite() ?
-- Thanks,
David / dhildenb
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