bcm4708-smartrg-sr400ac boot failures in next-20150918+

[hauke@hauke-m.de (Hauke Mehrtens)]

Adding the arm List.

On 10/01/2015 11:46 PM, Hauke Mehrtens wrote:
> On 10/01/2015 07:50 PM, Tyler Baker wrote:
>> Hi Hauke, Rafal,
>>
>> The kernelci.org bot has been reporting complete boot failures[1]
>> since next-20150918. I've bisected[2] the issue and found "ARM:
>> 8422/1: enable imprecise aborts during early kernel startup" is the
>> offending patch. Reverting this on top of -next fixes the boot issue.
>>
>> Apologies for sending this off list, but I want to make sure you can
>> confirm this issue before we raise it.
>>
>> Cheers,
>>
>> Tyler
>>
>> [1] http://kernelci.org/boot/bcm4708-smartrg-sr400ac/
>> [2] http://hastebin.com/mirunerobi.vhdl
>>
> Hi Tyler,
> 
> Thanks for the info, the broken bootloader causes some problems when
> booting the kernel, we already had to ignore some exceptions. I will
> look into this at the weekend.
> 
> Hauke
> 
Hi,

The commit "ARM: 8422/1: enable imprecise aborts during early kernel
startup" breaks bcm53xx devices with a broken boot loader, this is a
regression. There are probably millions of these devices shipped with
this boot loader called CFE.
For BCM53xx we install a fault handler in the init_early callback of
DT_MACHINE_START to ignore the faults produced by the boot loader in
http://lxr.free-electrons.com/source/arch/arm/mach-bcm/bcm_5301x.c#L40 ,
but init_early is called after local_abt_enable() gets called and this
causes a kernel panic because of any unhandled CPU fault. The reserve()
callback in DT_MACHINE_START was the only callback I could find which
gets called before local_abt_enable(), should I move the code which
installs the fault handler there?

This is causing the problems in kernelci with linux next kernels on this
board: http://kernelci.org/boot/bcm4708-smartrg-sr400ac/

Hauke