Messages in this thread | | | Date | Wed, 1 Mar 2023 07:39:08 -0800 | From | Deepak Gupta <> | Subject | Re: [PATCH v6 11/41] mm: Introduce pte_mkwrite_kernel() |
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On Sat, Feb 18, 2023 at 01:14:03PM -0800, 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: Deepak Gupta <debug@rivosinc.com>
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