On Thu, Feb 25, 2010 at 12:09 PM, Mikael Pettersson <mikpe@xxxxxxxx> wrote: > Brian Gerst wrote: >> Would barrier() (which is a simple memory clobber) after the memset work? > > I don't know. It's implemented as an asm with a "memory" clobber, > but I wouldn't bet on that forcing previous writes to a dying object > to actally be performed (it would have to have a data-dependency on > the dying object, but I don't think there is one). >From the GCC manual, section 5.37: If your assembler instructions access memory in an unpredictable fashion, add `memory' to the list of clobbered registers. This will cause GCC to not keep memory values cached in registers across the assembler instruction and not optimize stores or loads to that memory. You will also want to add the volatile keyword if the memory affected is not listed in the inputs or outputs of the asm, as the `memory' clobber does not count as a side-effect of the asm. -- Brian Gerst -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
