On Fri, May 25, 2018 at 2:01 AM, Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote: > On Thu, May 24, 2018 at 08:14:40PM -0700, Andrey Smirnov wrote: >> On Wed, May 23, 2018 at 1:43 AM, Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote: >> > On Tue, May 22, 2018 at 10:10:12PM -0700, Andrey Smirnov wrote: >> >> The call to create_flat_mapping() in mmu.c will change both memory >> >> type and shareability of all RAM in use by barebox while MMU is on >> >> when done in conjunction with CONFIG_MMU_EARLY. >> > >> > I notice that with MMU_EARLY enabled we call create_flat_mapping() >> > twice, once in the early MMU code and once when setting up the MMU for >> > real. In between we remap the the SDRAM cached which then is reverted >> > during the second call to create_flat_mapping(). >> > >> > This seems unnecessary. Does the following help you? >> >> Yeah, this, disabling MMU before or having a tlb_invalidate() after >> all seem to help. Your patch works fine, but it has a slight weirdness >> in my case because early MMU code would mark OCRAM as cached and >> regular MMU code wouldn't undo it without the call to >> create_flat_mapping(), so I'd end up with slightly different memory >> configuration depending on if EARLY_MMU is enabled or not. Other than >> that it should work fine. >> >> The main reason I chose to go "disable MMU" route is because that >> follows what ARMv8 MMU code does, but I am perfectly happy with either >> solution. > > Disabling the MMU probably has a performance impact (I would have to > remeasure, maybe this is not true at all), that's why I would prefer > keeping it enabled. > OK, sure. Where do we go from here? Do you want to just take your patch or should I update mine, with its War And Peace of a commit message, and incorporate what you proposed? Thanks, Andrey Smirnov _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
