On Fri, May 25, 2018 at 10:09:52AM -0700, Andrey Smirnov wrote: > 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? I applied my patch for now. We can still disable the MMU between PBL and barebox later should we have to. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
