Messages in this thread | | | Date | Tue, 02 Oct 2007 12:21:22 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] mark read_crX() asm code as volatile |
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Arjan van de Ven wrote: > On Tue, 02 Oct 2007 18:08:32 +0400 > Kirill Korotaev <dev@openvz.org> wrote: > >> Some gcc versions (I checked at least 4.1.1 from RHEL5 & 4.1.2 from >> gentoo) can generate incorrect code with read_crX()/write_crX() >> functions mix up, due to cached results of read_crX(). >> > > I'm not so sure volatile is the right answer, as compared to giving the > asm more strict contraints.... > > asm volatile tends to mean something else than "the result has > changed".... >
One of the aspect of volatility is "the result will change in ways you (gcc) just don't understand."
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