Messages in this thread | | | Date | Fri, 20 Apr 2012 10:46:47 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH 3/3] x86, extable: Handle early exceptions |
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On Thu, Apr 19, 2012 at 11:11:00AM -0700, Linus Torvalds wrote: > > OTOH, if we can share early and normal exception handling lookup code, then a > > perfect hash would make sense as those exceptions would pile up. > > Oh, any of this only makes sense if we can share it with the runtime > exception lookup. > > They are *seldom* hugely performance-critical, but there are some > unusual loads where you do get a fair number of exceptions.
I was thinking, and this is probably purely hypothetical and tangential to the topic but, what happens if we get an exception right in the middle between using the early_idt_handler's and switching to the normal trap handlers in trap_init()?
write_idt_entry() is a simple memcpy so what happens if we have a half-written descriptor? Won't we need some locking there to atomize the switch?
Or am I dreaming?
Thanks.
-- Regards/Gruss, Boris.
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