* H. Peter Anvin <hpa@xxxxxxxxx> wrote: > On 11/11/2013 11:37 AM, Kees Cook wrote: > > On Mon, Nov 11, 2013 at 11:27 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote: > >> On 11/11/2013 10:20 AM, Ingo Molnar wrote: > >>> > >>> Why aren't the 3 sources of entropy XOR-ed together? > >> > >> Note we don't want to poke i8254 if we have any other sources, as the > >> i8254 may not be present on newer systems and in some other cases not > >> safe to touch. We can XOR in the TSC with RDRAND although it seems a > >> bit odd. > > > > I await the final decision! :) > > > > Use the i8254 if and only if nothing else is available, it isn't safe to > touch on some newer systems. I concur - the i8254 is probably also a low entry source, given that this all runs early bootup. In any case there's no excuse for not mixing RDRAND and RDTSC entropy. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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