On Wed, 29 Aug 2018, Juergen Gross wrote: > While being very unlikely I still believe this is possible. Any > thoughts?
So in theory we should somehow test whether the next page is some form of mmio/gart/... mapping, but I guess that by itself would kill the performance advantage of the whole load_unaligned_zeropad() trick. And yes, the sideffects of reading from mmio mapping is a real thing -- see for example the issue fixed by 2a3e83c6f9. If noone has any clever idea how to work this around (I don't), I am afraid we'd have to ditch the whole DCACHE_WORD_ACCESS optimization, as it's silently dangerous. Thanks, -- Jiri Kosina SUSE Labs
