linux-kernel - Re: [PATCH v7 31/41] x86/shstk: Introduce routines modifying shstk

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Message-ID: <20230309172216.GHZAoVyHoTqLG+YKB4@fat_crate.local>
Date:   Thu, 9 Mar 2023 18:22:16 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
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Subject: Re: [PATCH v7 31/41] x86/shstk: Introduce routines modifying shstk

On Thu, Mar 09, 2023 at 05:03:26PM +0000, Edgecombe, Rick P wrote:
> On Thu, 2023-03-09 at 17:48 +0100, Borislav Petkov wrote:
> > On Mon, Feb 27, 2023 at 02:29:47PM -0800, Rick Edgecombe wrote:
> > > From: Yu-cheng Yu <yu-cheng.yu@...el.com>
> > > 
> > > Shadow stacks are normally written to via CALL/RET or specific CET
> > 
> >                                        ^
> >                                        indirectly.
> 
> Dunno here, RSTORSSP/SAVEPREVSSP are kind of direct.
> 
> > 
> > > instructions like RSTORSSP/SAVEPREVSSP. However during some Linux
> > > operations the kernel will need to write to directly using the
						  ^^^^^^^^^

Yes, I was trying to make the contrast more obvious because you say
"directly" here.

But not too important.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette