From: catalin.marinas@arm.com (Catalin Marinas)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: kernel: avoid literal load of virtual address with MMU off
Date: Wed, 17 Aug 2016 18:11:34 +0100 [thread overview]
Message-ID: <20160817171134.GF20762@e104818-lin.cambridge.arm.com> (raw)
In-Reply-To: <1471449281-10367-1-git-send-email-ard.biesheuvel@linaro.org>
On Wed, Aug 17, 2016 at 05:54:41PM +0200, Ard Biesheuvel wrote:
> Literal loads of virtual addresses are subject to runtime relocation when
> CONFIG_RELOCATABLE=y, and given that the relocation routines run with the
> MMU and caches enabled, literal loads of relocated values performed with
> the MMU off are not guaranteed to return the latest value unless the
> memory covering the literal is cleaned to the PoC explicitly.
>
> So defer the literal load until after the MMU has been enabled, just like
> we do for primary_switch() and secondary_switch() in head.S.
I think for consistency with head.S the patch is fine but do we actually
expect a literal pool value to be inconsistent between cache and PoC?
Presumably, the first time the kernel image was loaded it had to be
cleaned to PoC but after that we wouldn't expect modifications of the
literal pool data.
--
Catalin
next prev parent reply other threads:[~2016-08-17 17:11 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-17 15:54 [PATCH] arm64: kernel: avoid literal load of virtual address with MMU off Ard Biesheuvel
2016-08-17 16:16 ` Mark Rutland
2016-08-17 17:11 ` Catalin Marinas [this message]
2016-08-17 17:22 ` Mark Rutland
2016-08-17 17:26 ` Ard Biesheuvel
2016-08-18 8:34 ` Catalin Marinas
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