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Subject: Re: [PATCH v26 24/30] x86/cet/shstk: Introduce shadow stack token
 setup/verify routines
To:     Borislav Petkov <bp@alien8.de>,
        Eugene Syromiatnikov <esyr@redhat.com>
Cc:     x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org,
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        linux-arch@vger.kernel.org, linux-api@vger.kernel.org,
        Arnd Bergmann <arnd@arndb.de>,
        Andy Lutomirski <luto@kernel.org>,
        Balbir Singh <bsingharora@gmail.com>,
        Cyrill Gorcunov <gorcunov@gmail.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Florian Weimer <fweimer@redhat.com>,
        "H.J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Kees Cook <keescook@chromium.org>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Nadav Amit <nadav.amit@gmail.com>,
        Oleg Nesterov <oleg@redhat.com>, Pavel Machek <pavel@ucw.cz>,
        Peter Zijlstra <peterz@infradead.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        "Ravi V. Shankar" <ravi.v.shankar@intel.com>,
        Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>,
        Dave Martin <Dave.Martin@arm.com>,
        Weijiang Yang <weijiang.yang@intel.com>,
        Pengfei Xu <pengfei.xu@intel.com>,
        Haitao Huang <haitao.huang@intel.com>
References: <20210427204315.24153-1-yu-cheng.yu@intel.com>
 <20210427204315.24153-25-yu-cheng.yu@intel.com> <YKIfIEyW+sR+bDCk@zn.tnic>
 <e225e357-a1d5-9596-8900-79e6b94cf924@intel.com>
 <20210518001316.GR15897@asgard.redhat.com> <YKQATkbU4DJ/nC3T@zn.tnic>
From:   "Yu, Yu-cheng" <yu-cheng.yu@intel.com>
Message-ID: <10f74571-f8c4-9b08-0157-1570b30a1a6d@intel.com>
Date:   Tue, 18 May 2021 12:45:13 -0700
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On 5/18/2021 10:58 AM, Borislav Petkov wrote:
> On Tue, May 18, 2021 at 02:14:14AM +0200, Eugene Syromiatnikov wrote:
>> Speaking of which, I wonder what would happen if a 64-bit process makes
>> a 32-bit system call (using int 0x80, for example), and gets a signal.
> 
> I guess that's the next patch. And I see amluto has some concerns...
> 
> /me goes read.
> 

In the next revision, there will be no "signal context extension" 
struct.  However, the flow for 64, ia32 and x32 will be similar.  I will 
send that out after some testing.

Thanks,
Yu-cheng