Ingo Molnar <[EMAIL PROTECTED]> writes: > > Thomas Gleixner (1): > x86: EFI: fix use of unitialized variable and the cache logic
Your honor, I would like to register a differing opinion... I submitted that fix originally in a different form, but it got finally stripped down to this. However in my opinion the full version of the patch is still needed, otherwise EFI still does the mapping wrong. Even with this patch EFI still passes in ioremap (on 32bit) and fixmap (on 64bit) addresses to cpa which it will mishandle. On 64bit cpa will still change cache attributes on random low pages and cause illegal caching attribute aliases on both 32bit and 64bit. See http://marc.info/?l=linux-kernel&m=120290071713708&w=2 for details. git-x86#mm made some attempts to also fix this in pageattr.c which fixed some parts of the problem on 64bit (static_protections should be ok now), but not all (alias handling still not good) See http://marc.info/?l=linux-kernel&m=120290203315953&w=2 for details In particular the direct mapping cache alias handling for ioremap/fixmap (and EFI uses that) is not correct on both 32bit and 64bit. Also all ioremaps have this same problem so all uncached mappings are broken when the direct mapping happens to overlap them (common on 64bit with enough RAM). Right now when you do a uncached ioremap the direct mapping will not be changed, which causes illegal conflicting caching aliasing. My original patch above avoided that by not calling set_memory_uc() for the EFI case, but I did not fix the general ioremap case for other users yet (will send a patch later for this unless someone beats me to it) Note even with ioremap generally fixed the original patch http://marc.info/?l=linux-kernel&m=120284838904660&w=2 in its full form will be still needed to pass in the correct attribute to ioremap in the first place. I would recommend to either mark EFI CONFIG_BROKEN for now or apply the complete patch I posted earlier http://marc.info/?l=linux-kernel&m=120284838904660&w=2 or fix it in some other way in pageattr.c as described in http://marc.info/?l=linux-kernel&m=120290203315953&w=2 (although that might be intrusive and I don't think such a change would be a good idea at this stage of the release) And a separate patch fixing ioremap_nocache() will be needed too. -Andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
