On 12/13/2012 11:05 AM, Borislav Petkov wrote:

Ok, I grok it now. So, in most cases, mce.ip comes from pt_regs.ip which
is unsigned long so we're fine for both 32- and 64-bit. There's only the
case with precise RIP reporting where we get the rip from an MSR but
even then, it should be 4 bytes on 32-bit since our addresses there are
4 bytes.

So, actually struct mce should've had ->ip defined as an unsigned long
from the very beginning. But we can't change that now because this
struct is shared with userspace :(

Good thing, then,. otherwise we'd have a compat headache.

	-hpa
-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.