From mboxrd@z Thu Jan  1 00:00:00 1970
From: robert.jarzmik@free.fr (Robert Jarzmik)
Date: Tue, 08 Sep 2015 22:46:30 +0200
Subject: [PATCH] ARM: fix alignement of __bug_table section entries
In-Reply-To: <20150908200809.GC21084@n2100.arm.linux.org.uk> (Russell King's
 message of "Tue, 8 Sep 2015 21:08:09 +0100")
References: <20150902103955.GF6281@e103592.cambridge.arm.com>
 <878u8lx9hl.fsf@belgarion.home>
 <20150905142519.GN21084@n2100.arm.linux.org.uk>
 <87y4gkx04m.fsf@belgarion.home>
 <20150905203818.GO21084@n2100.arm.linux.org.uk>
 <87lhcjwjde.fsf@belgarion.home>
 <20150906194805.GP21084@n2100.arm.linux.org.uk>
 <87egibw7yh.fsf@belgarion.home>
 <20150906235414.GQ21084@n2100.arm.linux.org.uk>
 <877fo0x2ur.fsf@belgarion.home>
 <20150908200809.GC21084@n2100.arm.linux.org.uk>
Message-ID: <8737yowsex.fsf@belgarion.home>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Russell King - ARM Linux <linux@arm.linux.org.uk> writes:

> What should happen is:
Thanks very much for the explanation, hopefully I have enough material to fly on
my own now.

> Now, when you get the fault inside arm_copy_from_user(), you can
> print the DACR value saved at the time the fault was generated by
> printing the word above struct pt_regs on the stack - add to
> arch/arm/mm/fault.c:do_DataAbort():
>
> if (addr == 0xbf00202c) printk("DACR=0x%08x\n", *(u32 *)(regs + 1));
>
> before the "if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))" line.
> That'll tell us what the DACR register was when we saved it.
>
> If it isn't 0x75, then the next part of the puzzle is going to be
> working out why it isn't.
It's 0x55. I'll track down how this happens, there are not that many places
where DACR is touched, and I'm in a very controlled environement, so I can
cunningly place JTAG breakpoints and watch DACR.

I'll report once I have a better idea what is happening, that might take me a
couple of days given that most of my workforce is available on weekends only.

Thanks again for the free lesson.

-- 
Robert