Messages in this thread |  | | | Subject | Re: MMIO and gcc re-ordering issue | | From | Benjamin Herrenschmidt <> | | Date | Wed, 28 May 2008 07:10:21 +1000 |
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On Tue, 2008-05-27 at 08:35 -0700, Linus Torvalds wrote: > > On Tue, 27 May 2008, Benjamin Herrenschmidt wrote: > > > > Yes. As it is today, tg3 for example is potentially broken on all archs > > with newer gcc unless we either add "memory" clobber to readl/writel or > > stick some wmb's in there (just a random driver I picked). > > > > So Linus, what is your take on that matter ? > > Let's just serialize the damn things, and add a memory clobber to them. > > Expecting people to fix up all drivers is simply not going to happen. And > serializing things shouldn't be *that* expensive. People who cannot take > the expense can continue to use the magic __raw_writel() etc stuff.
Ok.
Do we also remove wmb/rmb/... from drivers then ? :-) I think ia64 would need to be fixed to make their writel serializing...
Regarding __raw_* their semantics are dodgy ... we might want to provide something better but it's a different subject.
Cheers, Ben.
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