linux-kernel - RE: [PATCH v26 23/30] x86/cet/shstk: Handle thread shadow stack

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Message-ID: <e22d3116efef4e25a45fc6b58d5622ef@AcuMS.aculab.com>
Date:   Wed, 12 May 2021 08:12:29 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Borislav Petkov' <bp@...en8.de>,
        "Yu, Yu-cheng" <yu-cheng.yu@...el.com>
CC:     "x86@...nel.org" <x86@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>,
        "linux-api@...r.kernel.org" <linux-api@...r.kernel.org>,
        Arnd Bergmann <arnd@...db.de>,
        Andy Lutomirski <luto@...nel.org>,
        Balbir Singh <bsingharora@...il.com>,
        Cyrill Gorcunov <gorcunov@...il.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "Eugene Syromiatnikov" <esyr@...hat.com>,
        Florian Weimer <fweimer@...hat.com>,
        "H.J. Lu" <hjl.tools@...il.com>, Jann Horn <jannh@...gle.com>,
        Jonathan Corbet <corbet@....net>,
        Kees Cook <keescook@...omium.org>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Nadav Amit <nadav.amit@...il.com>,
        Oleg Nesterov <oleg@...hat.com>, Pavel Machek <pavel@....cz>,
        Peter Zijlstra <peterz@...radead.org>,
        Randy Dunlap <rdunlap@...radead.org>,
        "Ravi V. Shankar" <ravi.v.shankar@...el.com>,
        Vedvyas Shanbhogue <vedvyas.shanbhogue@...el.com>,
        Dave Martin <Dave.Martin@....com>,
        "Weijiang Yang" <weijiang.yang@...el.com>,
        Pengfei Xu <pengfei.xu@...el.com>,
        "Haitao Huang" <haitao.huang@...el.com>
Subject: RE: [PATCH v26 23/30] x86/cet/shstk: Handle thread shadow stack

From: Borislav Petkov
> Sent: 11 May 2021 18:10
> 
> On Mon, May 10, 2021 at 03:57:56PM -0700, Yu, Yu-cheng wrote:
> > So this struct will be:
> >
> > struct thread_shstk {
> > 	u64 shstk_base;
> > 	u64 shstk_size;
> > 	u64 locked:1;
> > 	u64 ibt:1;

No point in bit fields?

> > };
> >
> > Ok?
> 
> Pretty much.
> 
> You can even remove the "shstk_" from the members and when you call the
> pointer "shstk", accessing the members will read
> 
> 	shstk->base
> 	shstk->size
> 	...
> 
> and all is organic and readable :)

And entirely not greppable.

	David

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