From mboxrd@z Thu Jan  1 00:00:00 1970
From: ariel@vanguardiasur.com.ar (Ariel D'Alessandro)
Date: Wed, 9 Sep 2015 15:25:41 -0300
Subject: ARM: domains: Possible regression in v7-M
In-Reply-To: <20150909175230.GF21084@n2100.arm.linux.org.uk>
References: <55F06797.3060706@gmail.com>
 <55F06C55.5070205@vanguardiasur.com.ar>
 <20150909175230.GF21084@n2100.arm.linux.org.uk>
Message-ID: <55F079A5.1010501@vanguardiasur.com.ar>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Russell,

El 09/09/15 a las 14:52, Russell King - ARM Linux escribi?:
> On Wed, Sep 09, 2015 at 02:28:53PM -0300, Ariel D'Alessandro wrote:
>> Doing a bisect I've observed that regression appears to be caused by:
>>
>> commit 1eef5d2f1b461c120bcd82077edee5ec706ac53b
>> Author: Russell King <rmk+kernel@arm.linux.org.uk>
>> Date:   Wed Aug 19 21:23:48 2015 +0100
>>
>>     ARM: domains: switch to keeping domain value in register
>>
>>
>> Stacktrace paste below.
>>
>> [    0.171071] Unhandled exception: IPSR = 00000006 LR = fffffff1
> 
> This looks to be ARMv7M, which is nommu...  I guess what's causing this
> is this change in arch/arm/kernel/process.c:
> 
> +       /*
> +        * Copy the initial value of the domain access control register
> +        * from the current thread: thread->addr_limit will have been
> +        * copied from the current thread via setup_thread_stack() in
> +        * kernel/fork.c
> +        */
> +       thread->cpu_domain = get_domain();
> +
> 
> which probably needs to be #ifdef'd out for !MMU.  Can you try adding:
> 
> #ifndef CONFIG_MMU

I think you meant #ifdef CONFIG_MMU.

> ...
> #endif
> 
> around that please?  Thanks.
> 

Yeah, that works!

Added:

#ifdef CONFIG_MMU
...
#endif

around that code block and it booted.

Thanks,

-- 
Ariel D'Alessandro, VanguardiaSur
www.vanguardiasur.com.ar