From: catalin.marinas@arm.com (Catalin Marinas)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: alignment: setup alignment handler earlier
Date: Wed, 7 Sep 2011 15:40:16 +0100 [thread overview]
Message-ID: <20110907144016.GA30719@e102109-lin.cambridge.arm.com> (raw)
In-Reply-To: <87ehzstr07.fsf@vostro.fn.ogness.net>
On Wed, Sep 07, 2011 at 02:35:04PM +0100, John Ogness wrote:
> From 6f3f381800367127dc6430d9b9fa9bd6fc6d8ed0 Mon Sep 17 00:00:00 2001
> From: John Ogness <john.ogness@linutronix.de>
>
> The alignment exception handler is setup fairly late in
> the boot process (fs_initcall). However, with newer gcc
> versions and the compiler option -fconserve-stack, code
> accessing unaligned data is generated in functions that
> are called earlier, for example pcpu_dump_alloc_info().
> This results in unhandled alignment exceptions during
> boot. By setting up the exception handler sooner, we
> reduce the window where a compiler may generate code
> accessing unaligned data.
While this reduces the window and fixes this particular case, it still
doesn't solve the problem. We never know when some unaligned access
would be generated for some earlier code.
I would just make sure that SCTLR.A bit is always cleared on ARMv6+,
independent of CONFIG_ALIGNMENT_TRAP.
--
Catalin
next prev parent reply other threads:[~2011-09-07 14:40 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-07 13:35 [PATCH] ARM: alignment: setup alignment handler earlier John Ogness
2011-09-07 13:54 ` Måns Rullgård
2011-09-07 14:28 ` Catalin Marinas
2011-09-07 14:40 ` Catalin Marinas [this message]
2011-09-07 16:28 ` Russell King - ARM Linux
2011-09-07 16:42 ` Måns Rullgård
2011-09-07 17:04 ` Russell King - ARM Linux
2011-09-07 17:24 ` Catalin Marinas
2011-09-07 17:40 ` Måns Rullgård
2011-09-07 16:43 ` Catalin Marinas
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