Benjamin Herrenschmidt wrote: >On Tue, 2004-06-01 at 00:36, Pantelis Antoniou wrote: > >>Hi >> >>The following patch fixes the problems of 8xx with the latest >>linuxppc-2.5 tree. >> >>With it user space progresses properly. >>Lots of gray areas remain and MM handling for 8xx is >>mighty inefficient IMO. >> >>Dan could you please take a look? >> > >Ok, looks a bit weird on the edges. > > I agree :)
>>Pantelis >> >> >>______________________________________________________________________ >>diff -Nur --exclude=RCS --exclude=CVS --exclude=SCCS --exclude=BitKeeper >>--exclude=ChangeSet linuxppc_2.5/arch/ppc/kernel/head_8xx.S >>linuxppc_2.5-intracom/arch/ppc/kernel/head_8xx.S >>--- linuxppc_2.5/arch/ppc/kernel/head_8xx.S Mon May 31 10:52:29 2004 >>+++ linuxppc_2.5-intracom/arch/ppc/kernel/head_8xx.S Mon May 31 17:24:05 2004 >>@@ -157,6 +157,24 @@ >> SAVE_2GPRS(7, r11) >> >> /* >>+if ((val & (_PAGE_HWWRITE | _PAGE_RW | _PAGE_DIRTY)) == (_PAGE_RW | >>_PAGE_DIRTY)) >>+ val |= _PAGE_HWWRITE; >>+else if ((val & (_PAGE_HWWRITE | _PAGE_RW | _PAGE_DIRTY)) == _PAGE_HWWRITE) >>+ val &= ~_PAGE_HWWRITE; >>+*/ >> > >I don't like the above. Things should be dealt with differently. > >The TLB handler itself should only care about _setting_ _PAGE_HWWRITE I >think when it's missing (oh, and dirty of course). The clearing should >be done on a per-PTE basis in ptep_get_and_clear_*, ptep_clear_*, etc... >along with the necessary TLB invalidate (hrm... can we invalidate >selectively instead of the whole thing ?) > Just setting HWWRITE is simple. > >The tlbia in update_mmu_cache() doesn't look good. More like a >workaround for breakage in the implementation. > It is :) When I tried a selective TLB invalidate it crashed in a spectacular way. That lazy TLB stuff just gave the mm system a good shake and it came apart. > >Paul, any comment ? > >Ben. > > Regards Pantelis P.S. Perusing the headers I came across a comment that said swap is broken on 8xx. For some reason I need to fix it. Where can I go about looking? ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
