svn commit: r205778 - in head/sys: amd64/amd64 i386/i386

[Alan Cox]

Author: alc
Date: Sat Mar 27 23:53:47 2010
New Revision: 205778
URL: http://svn.freebsd.org/changeset/base/205778

Log:
  Correctly handle preemption of pmap_update_pde_invalidate().
  
  X-MFC after:	r205573

Modified:
  head/sys/amd64/amd64/pmap.c
  head/sys/i386/i386/pmap.c

Modified: head/sys/amd64/amd64/pmap.c
==============================================================================
--- head/sys/amd64/amd64/pmap.c	Sat Mar 27 20:25:50 2010	(r205777)
+++ head/sys/amd64/amd64/pmap.c	Sat Mar 27 23:53:47 2010	(r205778)
@@ -880,9 +880,12 @@ pmap_update_pde_invalidate(vm_offset_t v
 		load_cr4(cr4 & ~CR4_PGE);
 		/*
 		 * Although preemption at this point could be detrimental to
-		 * performance, it would not lead to an error.
+		 * performance, it would not lead to an error.  PG_G is simply
+		 * ignored if CR4.PGE is clear.  Moreover, in case this block
+		 * is re-entered, the load_cr4() either above or below will
+		 * modify CR4.PGE flushing the TLB.
 		 */
-		load_cr4(cr4);
+		load_cr4(cr4 | CR4_PGE);
 	}
 }
 #ifdef SMP

Modified: head/sys/i386/i386/pmap.c
==============================================================================
--- head/sys/i386/i386/pmap.c	Sat Mar 27 20:25:50 2010	(r205777)
+++ head/sys/i386/i386/pmap.c	Sat Mar 27 23:53:47 2010	(r205778)
@@ -917,9 +917,12 @@ pmap_update_pde_invalidate(vm_offset_t v
 		load_cr4(cr4 & ~CR4_PGE);
 		/*
 		 * Although preemption at this point could be detrimental to
-		 * performance, it would not lead to an error.
+		 * performance, it would not lead to an error.  PG_G is simply
+		 * ignored if CR4.PGE is clear.  Moreover, in case this block
+		 * is re-entered, the load_cr4() either above or below will
+		 * modify CR4.PGE flushing the TLB.
 		 */
-		load_cr4(cr4);
+		load_cr4(cr4 | CR4_PGE);
 	}
 }
 #ifdef SMP