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From: Mark Brown <broonie@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>, Julien Grall <julien@xen.org>,
	Zhang Lei <zhang.lei@jp.fujitsu.com>,
	Dave Martin <Dave.Martin@arm.com>,
	Daniel Kiss <Daniel.Kiss@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm64/sve: Rework SVE access trap to convert state in registers
Date: Wed, 7 Apr 2021 16:55:39 +0100	[thread overview]
Message-ID: <20210407155539.GF5510@sirena.org.uk> (raw)
In-Reply-To: <20210407124806.GC5510@sirena.org.uk>


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On Wed, Apr 07, 2021 at 01:48:06PM +0100, Mark Brown wrote:
> On Wed, Apr 07, 2021 at 12:45:12PM +0100, Catalin Marinas wrote:

> > via do_el0_svc(). So it looks like we may restore some old SVE state
> > after a syscall (maybe I'm missing something but it would be nice to
> > follow zero or preserved approach).
> 
> The state is currently converted via the fpsimd_to_sve() call in the
> trap handler, that *should* be dealing with anything required for
> conversion.  You're right that this seems to miss zeroing anything
> outside of the values it immediately writes - I might be missing
> something though.  It's only going to leak information from the current

Actually I found that we do have the zeroing - it's done in sve_alloc()
where we either kzalloc() a new state or memset() an existing state so
that's covered already

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  reply	other threads:[~2021-04-07 15:58 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-12 19:03 [PATCH] arm64/sve: Rework SVE access trap to convert state in registers Mark Brown
2021-04-07 11:45 ` Catalin Marinas
2021-04-07 12:48   ` Mark Brown
2021-04-07 15:55     ` Mark Brown [this message]
2021-04-08 16:43     ` Catalin Marinas
2021-04-08 18:00 ` Catalin Marinas

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