Attached is a patch that adds lightweight memory scrubbing for
memory errors reported by CMCs and CPEs.  The goal is simply to
mark addresses reported by these corrected errors as dirty such
that the corrected value gets written back to memory.  For
platforms that do no support hardware memory scrubbing, this
should help ensure that single bit errors don't become multi-bit
errors and should reduce the occurrence of multiple CMCs for
the same memory address.  I'm assuming that platforms that do
support hardware scrubbing will fix single bit errors at the
chipset, eliminating the CMC, and thus making this addition
extremely lightweight.

   To scrub the memory, I simply issue an lfetch.excl to the
faulting address.  According to the Itanium 2 Optimization guide,
this will look like a write on the bus and puts the cacheline in
the M(odified) state.  Thanks to David for recommending this
method of scrubbing.

   To determine if an address needs scrubbing, I look for the
following:

  CMC - bus error w/ the eb (external bus) bit set.
  CPE - memory device error.

Ideally for the CMC, we could get the target address from the
bus error log.  Unfortunately, the CMC hardly ever (never in
my experience) sets the target address as valid.  Therefore,
if I see the signature from the CMC, but not a target address,
I kick the CPE poll to trigger (if we're in polling mode for
CPEs).

   I've also updated the CPE polling to poll on all processors.
For multi-node systems, this makes sure we get all the logs
we're after.

   This patch also fixes the timestamp for MCA logs.  The date
was correctly changed to be printed as BCD, but the time was
still being printed as decimal.  This patch applies cleanly
against 2.4.20 + ia64-021210 (I think 2.5 is missing the CPE
polling patch, which causes failures).  Feedback welcome.  Thanks,

	Alex

--
Alex Williamson                                  Linux Development Lab
alex_williamson@hp.com                                 Hewlett Packard
970-898-9173                                          Fort Collins, CO