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ah, I was wrong, it is a pmap bug.  pmap_pte_clear() is calling
TLBIE() on the address that contains the PTE rather than the address
that the PTE is mapping.  the attached diff fixes the problem.

I don't know what document that reference about "As shown in Section 7.6.3.2.2"
comes from, is that document wrong or did you just mis-read it, matt?

also, pmap_clear_bit() is doing some unnecessary work to compute
the pte's address, it could just check the PTE_VALID bit in the pvo's
copy of the pte and skip the pte processing if it's not set.

-Chuck


On Mon, Nov 05, 2001 at 11:26:49PM +0100, Markus W Kilbinger wrote:
> >>>>> "Chuck" == Chuck Silvers <chuq@chuq.com> writes:
> 
>     Chuck> at this point the new pmap appears to be much more stable
>     Chuck> than the old one, so I recommend that everyone turn on
>     Chuck> "options NEWPMAP" if you haven't done so already.
> 
> After all these changes I still see a strange nfs related problem,
> probably macppc specific, detected when trying to build a kernel in
> nfs mounted /usr/src:
> 
> Simply cd into such a nfs mounted directory on a macppc machine and
> execute
> 
>   sh /sys/conf/newvers.sh && cat vers.c
> 
> vers.c is missing most of its lines most of the time!
> 
> I could only reproduce this problem in this scenario (macppc nfs
> client, no matter what nfs server).
> 
> Is this also pmap related? Can anybody reproduce this problem?
> 
> Markus.

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Index: arch/powerpc/mpc6xx/pmap.c
===================================================================
RCS file: /cvsroot/syssrc/sys/arch/powerpc/mpc6xx/pmap.c,v
retrieving revision 1.34
diff -u -r1.34 pmap.c
--- arch/powerpc/mpc6xx/pmap.c	2001/11/06 06:25:28	1.34
+++ arch/powerpc/mpc6xx/pmap.c	2001/11/07 17:06:33
@@ -506,13 +506,13 @@
 }
 
 static __inline void
-pmap_pte_clear(volatile pte_t *pt, int ptebit)
+pmap_pte_clear(volatile pte_t *pt, int ptebit, vaddr_t va)
 {
 	/*
 	 * As shown in Section 7.6.3.2.2
 	 */
 	pt->pte_lo &= ~ptebit;
-	TLBIE(pt);
+	TLBIE(va);
 	EIEIO();
 	TLBSYNC();
 	SYNC();
@@ -2049,7 +2049,7 @@
 		pt = pmap_pvo_to_pte(pvo, -1);
 		if (pt != NULL) {
 			pmap_pte_synch(pt, &pvo->pvo_pte);
-			pmap_pte_clear(pt, ptebit);
+			pmap_pte_clear(pt, ptebit, pvo->pvo_vaddr);
 		}
 		rv |= pvo->pvo_pte.pte_lo;
 		pvo->pvo_pte.pte_lo &= ~ptebit;

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