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Subject: Re: [RFC PATCH v9 18/27] x86/cet/shstk: Introduce WRUSS instruction
From:   Yu-cheng Yu <yu-cheng.yu@intel.com>
To:     Kees Cook <keescook@chromium.org>
Cc:     x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
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Date:   Thu, 05 Mar 2020 10:39:08 -0800
In-Reply-To: <202002251309.E238DFEEB4@keescook>
References: <20200205181935.3712-1-yu-cheng.yu@intel.com>
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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