Hi Mark. 2016-04-15 22:05 GMT+09:00 Mark Rutland <mark.rutland@xxxxxxx>: > On Fri, Apr 15, 2016 at 07:30:47PM +0900, Masahiro Yamada wrote: >> The 8-byte register located at 0x59801200 on this SoC is dedicated >> for waking up secondary CPUs. We can use it and save normal memory. > > Generally, it is not safe to use MMIO registers to back spin-table. The > kernel maps the spin table location with cacheable attributes, so there > may be speculative accesses to any registes in the same (64K) page, and > a writeback may be larger than the 8-byte register width (which the > device might not accept, triggering an SError). > > Given that, I do not think this is a good idea. I did not know this. Thanks for your advice! Arnd, Olof Please drop this patch. (I think 1/2 is still OK.) -- Best Regards Masahiro Yamada -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
