Hello Ralf,
Ralf Baechle wrote on 2013-10-08:
> On Tue, Oct 08, 2013 at 11:48:54AM +0000, thomas.langer@xxxxxxxxxx wrote:
>
>>> void __noreturn nmi_exception_handler(struct pt_regs *regs)
>>> {
>>> + char str[100];
>>> +
>>> raw_notifier_call_chain(&nmi_chain, 0, regs);
>>> bust_spinlocks(1);
>>> - printk("NMI taken!!!!\n");
>>> - die("NMI", regs);
>>> + snprintf(str, 100, "CPU%d NMI taken, CP0_EPC=%lx\n",
>>> + smp_processor_id(), regs->cp0_epc);
>>> + regs->cp0_epc = read_c0_errorepc();
>>
>> If this is a YAMON specific fix, why is it done in a common file?
>
> The installation of an NMI handler is platform specific - this handler
> however in all its simplicity is generic - or at least trying to.
>
> The NMI on MIPS is notoriously hard to use. The vectors is pointing to
> the boot ROM so firmware first gets its grubby hands on a fresh NMI and
> on most systems it'll do the firmware equivalent of a panic or reset
> the system outright. If that's still working - it's about the worst
> tested functionality of firmware ...
I know, I am working on a chip which has working wrapper implemented in its bootrom:
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/mips/lantiq/falcon/prom.c#n90
Therefore I was triggered by the keyword NMI ;-)
So if this has nothing to do with YAMON and is some generic NMI specific fix:
Acked-By: Thomas Langer <thomas.langer@xxxxxxxxxx>
>
> Ralf
Best Regards,
Thomas
