Fix the following problem:

When creating new processes (or performing exec), the new page
directory is initialized too early.  The kernel might grow before
p_vmspace is initialized for the new process.  Since pmap_growkernel
doesn't yet know about the new page directory, it isn't updated, and
subsequent use causes a failure.

The fix is (1) to clear p_vmspace early, to stop pmap_growkernel
from stomping on memory, and (2) to defer part of the initialization
of new page directories until p_vmspace is initialized.

PR:		kern/12378
Submitted by:	tegge
Reviewed by:	dfr

sys/alpha/alpha/pmap.c

@@ -43,7 +43,7 @@
  *	from:	@(#)pmap.c	7.7 (Berkeley)	5/12/91
  *	from:	i386 Id: pmap.c,v 1.193 1998/04/19 15:22:48 bde Exp
  *		with some ideas from NetBSD's alpha pmap
- *	$Id: pmap.c,v 1.26 1999/06/10 20:40:55 dt Exp $
+ *	$Id: pmap.c,v 1.27 1999/06/28 09:38:09 peter Exp $
  */
 
 /*
@@ -1272,9 +1272,6 @@ pmap_pinit(pmap)
 	if ((lev1pg->flags & PG_ZERO) == 0)
 		bzero(pmap->pm_lev1, PAGE_SIZE);
 
-	/* wire in kernel global address entries */
-	/* XXX copies current process, does not fill in MPPTDI */
-	bcopy(PTlev1 + K1SEGLEV1I, pmap->pm_lev1 + K1SEGLEV1I, nklev2 * PTESIZE);
 
 	/* install self-referential address mapping entry (not PG_ASM) */
 	pmap->pm_lev1[PTLEV1I] = pmap_phys_to_pte(VM_PAGE_TO_PHYS(lev1pg))
@@ -1290,6 +1287,19 @@ pmap_pinit(pmap)
 	bzero(&pmap->pm_stats, sizeof pmap->pm_stats);
 }
 
+/*
+ * Wire in kernel global address entries.  To avoid a race condition
+ * between pmap initialization and pmap_growkernel, this procedure
+ * should be called after the vmspace is attached to the process
+ * but before this pmap is activated.
+ */
+void
+pmap_pinit2(pmap)
+	struct pmap *pmap;
+{
+	bcopy(PTlev1 + K1SEGLEV1I, pmap->pm_lev1 + K1SEGLEV1I, nklev2 * PTESIZE);
+}
+
 static int
 pmap_release_free_page(pmap_t pmap, vm_page_t p)
 {

sys/amd64/amd64/pmap.c

@@ -39,7 +39,7 @@
  * SUCH DAMAGE.
  *
  *	from:	@(#)pmap.c	7.7 (Berkeley)	5/12/91
- *	$Id: pmap.c,v 1.240 1999/06/23 21:47:21 luoqi Exp $
+ *	$Id: pmap.c,v 1.241 1999/07/08 06:05:49 mckusick Exp $
  */
 
 /*
@@ -1172,9 +1172,6 @@ pmap_pinit(pmap)
 	if ((ptdpg->flags & PG_ZERO) == 0)
 		bzero(pmap->pm_pdir, PAGE_SIZE);
 
-	/* wire in kernel global address entries */
-	/* XXX copies current process, does not fill in MPPTDI */
-	bcopy(PTD + KPTDI, pmap->pm_pdir + KPTDI, nkpt * PTESIZE);
 #ifdef SMP
 	pmap->pm_pdir[MPPTDI] = PTD[MPPTDI];
 #endif
@@ -1190,6 +1187,20 @@ pmap_pinit(pmap)
 	bzero(&pmap->pm_stats, sizeof pmap->pm_stats);
 }
 
+/*
+ * Wire in kernel global address entries.  To avoid a race condition
+ * between pmap initialization and pmap_growkernel, this procedure
+ * should be called after the vmspace is attached to the process
+ * but before this pmap is activated.
+ */
+void
+pmap_pinit2(pmap)
+	struct pmap *pmap;
+{
+	/* XXX copies current process, does not fill in MPPTDI */
+	bcopy(PTD + KPTDI, pmap->pm_pdir + KPTDI, nkpt * PTESIZE);
+}
+
 static int
 pmap_release_free_page(pmap, p)
 	struct pmap *pmap;

sys/i386/i386/pmap.c

@@ -39,7 +39,7 @@
  * SUCH DAMAGE.
  *
  *	from:	@(#)pmap.c	7.7 (Berkeley)	5/12/91
- *	$Id: pmap.c,v 1.240 1999/06/23 21:47:21 luoqi Exp $
+ *	$Id: pmap.c,v 1.241 1999/07/08 06:05:49 mckusick Exp $
  */
 
 /*
@@ -1172,9 +1172,6 @@ pmap_pinit(pmap)
 	if ((ptdpg->flags & PG_ZERO) == 0)
 		bzero(pmap->pm_pdir, PAGE_SIZE);
 
-	/* wire in kernel global address entries */
-	/* XXX copies current process, does not fill in MPPTDI */
-	bcopy(PTD + KPTDI, pmap->pm_pdir + KPTDI, nkpt * PTESIZE);
 #ifdef SMP
 	pmap->pm_pdir[MPPTDI] = PTD[MPPTDI];
 #endif
@@ -1190,6 +1187,20 @@ pmap_pinit(pmap)
 	bzero(&pmap->pm_stats, sizeof pmap->pm_stats);
 }
 
+/*
+ * Wire in kernel global address entries.  To avoid a race condition
+ * between pmap initialization and pmap_growkernel, this procedure
+ * should be called after the vmspace is attached to the process
+ * but before this pmap is activated.
+ */
+void
+pmap_pinit2(pmap)
+	struct pmap *pmap;
+{
+	/* XXX copies current process, does not fill in MPPTDI */
+	bcopy(PTD + KPTDI, pmap->pm_pdir + KPTDI, nkpt * PTESIZE);
+}
+
 static int
 pmap_release_free_page(pmap, p)
 	struct pmap *pmap;

sys/kern/kern_fork.c

@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)kern_fork.c	8.6 (Berkeley) 4/8/94
- * $Id: kern_fork.c,v 1.62 1999/06/30 15:33:34 peter Exp $
+ * $Id: kern_fork.c,v 1.63 1999/07/03 20:58:44 peter Exp $
  */
 
 #include "opt_ktrace.h"
@@ -249,6 +249,8 @@ fork1(p1, flags, procp)
 
 	newproc->p_wakeup = 0;
 
+	newproc->p_vmspace = NULL;
+
 	/*
 	 * Find an unused process ID.  We remember a range of unused IDs
 	 * ready to use (from nextpid+1 through pidchecked-1).

sys/vm/pmap.h

@@ -61,7 +61,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- * $Id: pmap.h,v 1.29 1999/04/05 19:38:29 julian Exp $
+ * $Id: pmap.h,v 1.30 1999/04/23 20:29:57 dt Exp $
  */
 
 /*
@@ -121,6 +121,7 @@ void		 pmap_pageable __P((pmap_t, vm_offset_t, vm_offset_t,
 vm_offset_t	 pmap_phys_address __P((int));
 void		 pmap_pinit __P((pmap_t));
 void		 pmap_pinit0 __P((pmap_t));
+void		 pmap_pinit2 __P((pmap_t));
 void		 pmap_protect __P((pmap_t, vm_offset_t, vm_offset_t,
 		    vm_prot_t));
 void		 pmap_qenter __P((vm_offset_t, vm_page_t *, int));

sys/vm/vm_glue.c

@@ -59,7 +59,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- * $Id: vm_glue.c,v 1.85 1999/04/06 03:11:34 peter Exp $
+ * $Id: vm_glue.c,v 1.86 1999/06/19 18:42:49 alc Exp $
  */
 
 #include "opt_rlimit.h"
@@ -226,6 +226,8 @@ vm_fork(p1, p2, flags)
 	if ((flags & RFMEM) == 0) {
 		p2->p_vmspace = vmspace_fork(p1->p_vmspace);
 
+		pmap_pinit2(vmspace_pmap(p2->p_vmspace));
+
 		if (p1->p_vmspace->vm_shm)
 			shmfork(p1, p2);
 	}

sys/vm/vm_map.c

@@ -61,7 +61,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- * $Id: vm_map.c,v 1.171 1999/07/01 19:53:41 peter Exp $
+ * $Id: vm_map.c,v 1.172 1999/07/11 18:30:31 alc Exp $
  */
 
 /*
@@ -2351,6 +2351,7 @@ vmspace_exec(struct proc *p) {
 	 */
 	vmspace_free(oldvmspace);
 	p->p_vmspace = newvmspace;
+	pmap_pinit2(vmspace_pmap(newvmspace));
 	if (p == curproc)
 		pmap_activate(p);
 }
@@ -2370,6 +2371,7 @@ vmspace_unshare(struct proc *p) {
 	newvmspace = vmspace_fork(oldvmspace);
 	vmspace_free(oldvmspace);
 	p->p_vmspace = newvmspace;
+	pmap_pinit2(vmspace_pmap(newvmspace));
 	if (p == curproc)
 		pmap_activate(p);
 }