From: tixy@yxit.co.uk (Tixy)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: kprobes: Restrict probing SWP instructions to ARMv5 and below
Date: Thu, 01 Dec 2011 07:40:55 +0000 [thread overview]
Message-ID: <1322725255.2352.8.camel@computer2> (raw)
In-Reply-To: <20111130235618.GX9581@n2100.arm.linux.org.uk>
On Wed, 2011-11-30 at 23:56 +0000, Russell King - ARM Linux wrote:
> On Sun, Nov 27, 2011 at 12:14:40PM +0000, Tixy wrote:
> > The SWP instruction is deprecated on ARMv6 and with ARMv7 it will be
> > UNDEFINED when CONFIG_SWP_EMULATE is selected. In this case, probing a
> > SWP instruction will cause an oops when the kprobes emulation code
> > executes an undefined instruction.
> >
> > As the SWP instruction should be rare or non-existent in kernels for
> > ARMv6 and later, we can simply avoid these problems by not allowing
> > probing of these.
>
> Is this something for -stable stuff?
It affects 3.1, though in practice I doubt there are any SWP
instructions to probe in an ARMv7 kernel with CONFIG_SWP_EMULATE
enabled. It was only the test code, added to 3.2, that tested the
emulation of SWP instructions and showed up the problem.
--
Tixy
prev parent reply other threads:[~2011-12-01 7:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-27 12:14 [PATCH] ARM: kprobes: Restrict probing SWP instructions to ARMv5 and below Tixy
2011-11-28 16:30 ` Nicolas Pitre
2011-11-30 23:56 ` Russell King - ARM Linux
2011-12-01 7:40 ` Tixy [this message]
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