From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yu-cheng Yu Subject: Re: [RFC PATCH v9 18/27] x86/cet/shstk: Introduce WRUSS instruction Date: Thu, 05 Mar 2020 10:39:08 -0800 Message-ID: <5dcc9da2caff92a9af16846cbe1f168f61368c51.camel@intel.com> References: <20200205181935.3712-1-yu-cheng.yu@intel.com> <20200205181935.3712-19-yu-cheng.yu@intel.com> <202002251309.E238DFEEB4@keescook> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <202002251309.E238DFEEB4@keescook> Sender: linux-doc-owner@vger.kernel.org To: Kees Cook Cc: x86@kernel.org, "H. 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 , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel List-Id: linux-arch.vger.kernel.org On Tue, 2020-02-25 at 13:10 -0800, Kees Cook wrote: > On Wed, Feb 05, 2020 at 10:19:26AM -0800, Yu-cheng Yu wrote: > > WRUSS is a new kernel-mode instruction but writes directly to user Shadow > > Stack (SHSTK) memory. This is used to construct a return address on SHSTK > > for the signal handler. > > > > This instruction can fault if the user SHSTK is not valid SHSTK memory. > > In that case, the kernel does a fixup. > > Since these functions aren't used in this patch, should this get merged > with patch 19? Yes, I can do that. Yu-cheng From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <5dcc9da2caff92a9af16846cbe1f168f61368c51.camel@intel.com> Subject: Re: [RFC PATCH v9 18/27] x86/cet/shstk: Introduce WRUSS instruction From: Yu-cheng Yu Date: Thu, 05 Mar 2020 10:39:08 -0800 In-Reply-To: <202002251309.E238DFEEB4@keescook> References: <20200205181935.3712-1-yu-cheng.yu@intel.com> <20200205181935.3712-19-yu-cheng.yu@intel.com> <202002251309.E238DFEEB4@keescook> Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-doc-owner@vger.kernel.org To: Kees Cook Cc: x86@kernel.org, "H. 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 , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , x86-patch-review@intel.com List-ID: Message-ID: <20200305183908.se7gspHfn87tzjvSzQdprAJHAwwKnt5Wrm59-MQ-1YY@z> On Tue, 2020-02-25 at 13:10 -0800, Kees Cook wrote: > On Wed, Feb 05, 2020 at 10:19:26AM -0800, Yu-cheng Yu wrote: > > WRUSS is a new kernel-mode instruction but writes directly to user Shadow > > Stack (SHSTK) memory. This is used to construct a return address on SHSTK > > for the signal handler. > > > > This instruction can fault if the user SHSTK is not valid SHSTK memory. > > In that case, the kernel does a fixup. > > Since these functions aren't used in this patch, should this get merged > with patch 19? Yes, I can do that. Yu-cheng