Messages in this thread | | | Date | Fri, 11 Jun 2010 15:41:00 -0700 | From | "H. Peter Anvin" <> | Subject | Re: sequence lock in Linux |
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On 06/11/2010 03:04 PM, Paul E. McKenney wrote: > On Fri, Jun 11, 2010 at 02:38:59PM -0700, H. Peter Anvin wrote: >> On 06/11/2010 02:36 PM, Paul E. McKenney wrote: >>> Memory barriers in the sequence-lock code prevent this, assuming, as >>> you point out, that memory clobber works (but if it doesn't, it should >>> be fixed): >> >> The constness is my main concern. It's not clear to me that "memory" is >> meant to imply that const memory areas without volatile can be clobbered. > > Ah! I was assuming that gcc treated "memory" as it would an call to > a function in some other compilation unit. In that case, the compiler > could not count on the "const" on the argument, given the possibility > that the called function might gain a reference to the same memory > locations in a non-const manner, right? > > Thanx, Paul
Right.
-hpa
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