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Lu" , Dave Hansen , Yu-cheng Yu , the arch/x86 maintainers , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , LKML , "open list:DOCUMENTATION" , Linux-MM , linux-arch , Linux API , Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang Subject: Re: [PATCH v10 01/26] Documentation/x86: Add CET description Message-ID: <20200522164953.GA411971@hirez.programming.kicks-ass.net> References: <20200429220732.31602-2-yu-cheng.yu@intel.com> <5cc163ff9058d1b27778e5f0a016c88a3b1a1598.camel@intel.com> <44c055342bda4fb4730703f987ae35195d1d0c38.camel@intel.com> <32235ffc-6e6c-fb3d-80c4-a0478e2d0e0f@intel.com> <6272c481-af90-05c5-7231-3ba44ff9bd02@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, May 16, 2020 at 03:09:22PM +0100, Andrew Cooper wrote: > Sadly, the same is not true for kernel shadow stacks. > > SSP is 0 after SYSCALL, SYSENTER and CLRSSBSY, and you've got to be > careful to re-establish the shadow stack before a CALL, interrupt or > exception tries pushing a word onto the shadow stack at 0xfffffffffffffff8. Oh man, I can only imagine the joy that brings to #NM and friends :-(