RE: [RFC] ACPI, APEI, Generic Hardware Error Source POLL/IRQ/NMI notification type support

[Huang Ying <ying.huang@intel.com>]

On Thu, 2010-12-16 at 00:40 +0800, Luck, Tony wrote:
> >Because the memory area used to transfer hardware error information
> >from BIOS to Linux can be determined only in NMI, IRQ or timer
> >handler, but general ioremap can not be used in atomic context, so a
> >special version of atomic ioremap is implemented for that.
> >
> >Known issue:
> >
> >- Error information can not be printed for recoverable errors notified
> >  via NMI, because printk is not NMI-safe. Will fix this via delay
> >  printing to IRQ context via irq_work or make printk NMI-safe.
> 
> Would it be possible to defer the "ioremap" to a work queue too? Then
> we wouldn't need the special versions of ioremap.

For recoverable error, we can defer the "ioremap" to a work queue,
because most recoverable action can take place only there in fact. But
for fatal error, I think it is too late to be processed in a work queue,
we need go panic as soon as possible to prevent data corruption.

Best Regards,
Huang Ying