From 76589fafd476824aadf83c79436658c43d68801c Mon Sep 17 00:00:00 2001
From: thorpej <thorpej@NetBSD.org>
Date: Wed, 11 Oct 2000 17:27:58 +0000
Subject: [PATCH] - uvmspace_share(): If p2 has a vmspace already, make sure to
 deactivate   it and free it as appropriate.  Activate p2's new address space
 once   it references p1's. - uvm_fork(): Make sure the child's vmspace is
 NULL before calling   uvmspace_share() (the child doens't have one already in
 this case).

These changes do not change the behavior for the current use of
uvmspace_share() (vfork(2)), but make it possible for an already
running process (such as a kernel thread) to properly attach to
another process's address space.
---
 sys/uvm/uvm_glue.c |  7 ++++---
 sys/uvm/uvm_map.c  | 11 ++++++++++-
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/sys/uvm/uvm_glue.c b/sys/uvm/uvm_glue.c
index 3a4947f45d29..19b1d819c2bd 100644
--- a/sys/uvm/uvm_glue.c
+++ b/sys/uvm/uvm_glue.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: uvm_glue.c,v 1.41 2000/09/23 00:43:10 enami Exp $	*/
+/*	$NetBSD: uvm_glue.c,v 1.42 2000/10/11 17:27:59 thorpej Exp $	*/
 
 /* 
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -278,9 +278,10 @@ uvm_fork(p1, p2, shared, stack, stacksize, func, arg)
 	struct user *up = p2->p_addr;
 	int rv;
 
-	if (shared == TRUE)
+	if (shared == TRUE) {
+		p2->p_vmspace = NULL;
 		uvmspace_share(p1, p2);			/* share vmspace */
-	else
+	} else
 		p2->p_vmspace = uvmspace_fork(p1->p_vmspace); /* fork vmspace */
 
 	/*
diff --git a/sys/uvm/uvm_map.c b/sys/uvm/uvm_map.c
index 2e02cc2d9512..de35d928413d 100644
--- a/sys/uvm/uvm_map.c
+++ b/sys/uvm/uvm_map.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: uvm_map.c,v 1.82 2000/10/11 17:21:11 thorpej Exp $	*/
+/*	$NetBSD: uvm_map.c,v 1.83 2000/10/11 17:27:58 thorpej Exp $	*/
 
 /* 
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -2779,8 +2779,17 @@ void
 uvmspace_share(p1, p2)
 	struct proc *p1, *p2;
 {
+	struct vmspace *ovm = p2->p_vmspace;
+
+	if (ovm != NULL)
+		pmap_deactivate(p2);
+
 	p2->p_vmspace = p1->p_vmspace;
 	p1->p_vmspace->vm_refcnt++;
+	pmap_activate(p2);
+
+	if (ovm != NULL)
+		uvmspace_free(ovm);
 }
 
 /*