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Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H . J . Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , Weijiang Yang , "Kirill A . Shutemov" , John Allen , kcc@google.com, eranian@google.com, rppt@kernel.org, jamorris@linux.microsoft.com, dethoma@microsoft.com, akpm@linux-foundation.org, Andrew.Cooper3@citrix.com, christina.schimpe@intel.com, david@redhat.com, linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org, xen-devel@lists.xenproject.org Subject: Re: [PATCH v6 11/41] mm: Introduce pte_mkwrite_kernel() Message-ID: <20230301153908.GA3505369@debug.ba.rivosinc.com> References: <20230218211433.26859-1-rick.p.edgecombe@intel.com> <20230218211433.26859-12-rick.p.edgecombe@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20230218211433.26859-12-rick.p.edgecombe@intel.com> X-Rspamd-Queue-Id: 889B318001D X-Stat-Signature: oucr3jdqsfosnt71eb3u9ppupcas5g9a X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1677685153-894609 X-HE-Meta: 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 71vw//s8 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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 >Suggested-by: David Hildenbrand >Signed-off-by: Rick Edgecombe > Acked-by: Deepak Gupta