linux-kernel - Re: [PATCH v9 23/42] Documentation/x86: Add CET shadow stack description

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Message-ID: <16147d5c-3f4c-4be0-8af1-9cd34d010363@sirena.org.uk>
Date:   Mon, 3 Jul 2023 19:38:04 +0100
From:   Mark Brown <broonie@...nel.org>
To:     "szabolcs.nagy@....com" <szabolcs.nagy@....com>
Cc:     "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>,
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Subject: Re: [PATCH v9 23/42] Documentation/x86: Add CET shadow stack
 description

On Mon, Jul 03, 2023 at 07:19:00PM +0100, szabolcs.nagy@....com wrote:
> The 07/02/2023 18:03, Edgecombe, Rick P wrote:

> > 3. Support more options for shadow stack sizing. (I think you are
> > referring to this conversation:
> > https://lore.kernel.org/lkml/ZAIgrXQ4670gxlE4@arm.com/). I don't see
> > why this is needed for the base implementation. If ARM wants to add a
> > new rlimit or clone variant, I don't see why x86 can't support it
> > later.

> i think it can be added later.

> but it may be important for deployment on some platforms, since a
> libc (or other language runtime) may want to set the shadow stack
> size differently than the kernel default, because

I agree that this can be deferred to later, so long as we err on the
side of large stacks now we can provide an additional limit without
confusing things.

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