On Mon, Jun 09, 2014 at 02:24:29PM +0100, Leif Lindholm wrote: > On Mon, Jun 09, 2014 at 12:03:56PM +0100, Catalin Marinas wrote: > > A quick grep through the kernel shows that we have other set_pte() calls > > without additional dsb() like create_mapping(), I think kvm_set_pte() as > > well. > > > > So I'm proposing an alternative patch (which needs some benchmarking as > > well to see if anything is affected, maybe application startup time). > > I'm happy for any fix which can be included in 3.16.
Steve Capper made a point about performance. He'll follow up. > But is the dsb(ishst) sufficient? We need to also prevent reads from > overtaking the set_pte(). i.e.: > > ptr = early_ioremap(phys_addr, size); > if (ptr && strcmp(ptr, "magic") == 0) > ... > > Does it not require a dsb(ish)? So doesn't early_ioremap() now include a dsb() after set_pte() with my patch? BTW, according to the ARM ARM (and confirmed with architects), we needs DSB+ISB even if we have just a data access (rather than instruction fetch). We have to revisit both 32 and 64-bit code for this. -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
