svn commit: r305191 - head/sys/arm64/arm64

[Andrew Turner]

Author: andrew
Date: Thu Sep  1 10:26:06 2016
New Revision: 305191
URL: https://svnweb.freebsd.org/changeset/base/305191

Log:
  Fix arm64 superpages bugs in pmap_enter:
   * Pass the correct virtual address when demoting a superpage
   * Use the correct l3 table after demoting a superpage
   * Remove an invalid KASSERT hit demoting then promoting a superpage [1]
  
  With this it is believed that  superpages on arm64 is stable.
  
  Reported by:	[1] cognet
  Obtained from:	ABT Systems Ltd
  MFC after:	1 week
  Sponsored by:	The FreeBSD Foundation

Modified:
  head/sys/arm64/arm64/pmap.c

Modified: head/sys/arm64/arm64/pmap.c
==============================================================================
--- head/sys/arm64/arm64/pmap.c	Thu Sep  1 08:34:31 2016	(r305190)
+++ head/sys/arm64/arm64/pmap.c	Thu Sep  1 10:26:06 2016	(r305191)
@@ -2732,7 +2732,9 @@ pmap_enter(pmap_t pmap, vm_offset_t va, 
 	if (pde != NULL && lvl == 1) {
 		l2 = pmap_l1_to_l2(pde, va);
 		if ((pmap_load(l2) & ATTR_DESCR_MASK) == L2_BLOCK &&
-		    (l3 = pmap_demote_l2_locked(pmap, l2, va, &lock)) != NULL) {
+		    (l3 = pmap_demote_l2_locked(pmap, l2, va & ~L2_OFFSET,
+		    &lock)) != NULL) {
+			l3 = &l3[pmap_l3_index(va)];
 			if (va < VM_MAXUSER_ADDRESS) {
 				mpte = PHYS_TO_VM_PAGE(
 				    pmap_load(l2) & ~ATTR_MASK);
@@ -2944,7 +2946,6 @@ validate:
 		    pmap_superpages_enabled() &&
 		    (m->flags & PG_FICTITIOUS) == 0 &&
 		    vm_reserv_level_iffullpop(m) == 0) {
-			KASSERT(lvl == 2, ("Invalid pde level %d", lvl));
 			pmap_promote_l2(pmap, pde, va, &lock);
 		}
 	}