Messages in this thread | | | Date | Fri, 13 Dec 2013 11:39:03 +0000 | From | Russell King - ARM Linux <> | Subject | Re: [PATCH] ARM: reinsert ARCH_MULTI_V4 Kconfig option |
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On Fri, Dec 13, 2013 at 11:51:09AM +0100, Jonas Jensen wrote: > On 13 December 2013 10:56, Russell King - ARM Linux > <linux@arm.linux.org.uk> wrote: > > So, having these symbols enabled (provided the right ones for FA526 are > > also enabled) makes no difference. So I don't buy your explanation. > > The explanation is indeed false, CPU_FA526 and CPU_ARM920T get along just fine. > That's not where the problem is. > > Panic goes away after removing CONFIG_ARM_THUMB=y. > > I assume this is what should happen on processors without thumb?
I see what's causing this: the kuser helpers are using "bx lr" to return which will be undefined on non-Thumb CPUs. We generally cope fine with non-Thumb CPUs, conditionalising where necessary on HWCAP_THUMB or the T bit in the PSR being set.
However, it looks like the kuser helpers got missed. As a check, please look at arch/arm/kernel/entry-armv.S, find the line with:
.macro usr_ret, reg
and ensure that the mov pc, \reg case always gets used. Please report back.
Thanks.
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