Messages in this thread | | | Date | Thu, 14 Aug 2008 14:53:38 -0400 | From | Mathieu Desnoyers <> | Subject | Re: [RFC PATCH] x86 alternatives : fix LOCK_PREFIX race with preemptible kernel and CPU hotplug |
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* H. Peter Anvin (hpa@zytor.com) wrote: > Jeremy Fitzhardinge wrote: >> Ah, OK. I'd thought we started unlocked, but given that I've just been >> disassembling the kernel and looking at the lock prefixes, that's a bit of >> a braino on my part. >> BTW, using the ds prefix allows us to undo the hack of dealing with locked >> instructions with exception handlers. There was a bug where if we do >> lock->nop, then the address of a faulting instruction changes, so we need >> exception records for both the locked and unlocked forms. Using ds means >> the instruction size doesn't change, so we only need one exception record. >> I don't remember off hand where that happens. > > Using %ds: rather than nop really seems to solve a whole lot of problems, > and might even be faster to boot. It really sounds like a no-brainer. > > -hpa
So should I wait a bit for more comments or straightforwardly submit this as a patch rather than RFC ?
Mathieu
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