From: catalin.marinas@arm.com (Catalin Marinas)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: kaslr: use callee saved register to preserve SCTLR across C call
Date: Thu, 24 Mar 2016 16:19:37 +0000 [thread overview]
Message-ID: <20160324161937.GD9113@e104818-lin.cambridge.arm.com> (raw)
In-Reply-To: <1458581711-13950-1-git-send-email-ard.biesheuvel@linaro.org>
On Mon, Mar 21, 2016 at 06:35:11PM +0100, Ard Biesheuvel wrote:
> The KASLR code incorrectly expects the contents of x18 to be preserved
> across a call into C code, and uses it to stash the contents of SCTLR_EL1
> before enabling the MMU. If the MMU needs to be disabled again to create
> the randomized kernel mapping, x18 is written back to SCTLR_EL1, which is
> likely to crash the system if x18 has been clobbered by kasan_early_init()
> or kaslr_early_init(). So use x22 instead, which is not in use so far in
> head.S
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Applied. Thanks.
--
Catalin
prev parent reply other threads:[~2016-03-24 16:19 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-21 17:35 [PATCH] arm64: kaslr: use callee saved register to preserve SCTLR across C call Ard Biesheuvel
2016-03-24 16:19 ` Catalin Marinas [this message]
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