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List:       linux-api
Subject:    Re: [PATCH v26 3/9] x86/cet/ibt: Handle signals for Indirect Branch Tracking
From:       Kees Cook <keescook () chromium ! org>
Date:       2021-04-28 20:31:07
Message-ID: 202104281331.C09D5479E () keescook
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On Tue, Apr 27, 2021 at 01:47:14PM -0700, Yu-cheng Yu wrote:
> When an indirect CALL/JMP instruction is executed and before it reaches
> the target, it is in 'WAIT_ENDBR' status, which can be read from
> MSR_IA32_U_CET.  The status is part of a task's status before a signal is
> raised and preserved in the signal frame.  It is restored for sigreturn.
> 
> IBT state machine is described in Intel SDM Vol. 1, Sec. 18.3.
> 
> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook
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