Add (but don't activate) code for a special VM option to make

downward growing stacks more general.
Add (but don't activate) code to use the new stack facility
when running threads, (specifically the linux threads support).
This allows people to use both linux compiled linuxthreads, and also the
native FreeBSD linux-threads port.

The code is conditional on VM_STACK. Not using this will
produce the old heavily tested system.

Submitted by: Richard Seaman <dick@tar.com>

1 files changed, 46 insertions, 47 deletions

diff --git a/sys/compat/linux/linux_misc.c b/sys/compat/linux/linux_misc.c
index 3bdc805..02f9785 100644
--- a/sys/compat/linux/linux_misc.c
+++ b/sys/compat/linux/linux_misc.c
@@ -25,7 +25,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- *  $Id: linux_misc.c,v 1.49 1998/12/24 21:21:20 julian Exp $
+ *  $Id: linux_misc.c,v 1.50 1998/12/30 21:01:33 sos Exp $
  */
 
 #include <sys/param.h>
@@ -688,45 +688,44 @@ linux_mmap(struct proc *p, struct linux_mmap_args *args)
     bsd_args.len = linux_args.len;
 #else
 
-    /*#if !defined(USE_VM_STACK) && !defined(USE_VM_STACK_FOR_EXEC)*/
+#ifndef VM_STACK
     /* Linux Threads will map into the proc stack space, unless
-       we prevent it.  This causes problems if we're not using
-       our VM_STACK options.
-    */
+     * we prevent it.  This causes problems if we're not using
+     * our VM_STACK options.
+     */
     if ((unsigned int)linux_args.addr + linux_args.len > (USRSTACK - MAXSSIZ))
-        return (EINVAL);
-    /*#endif*/
+	return (EINVAL);
+#endif
 
     if (linux_args.flags & LINUX_MAP_GROWSDOWN) {
 
-#ifdef USE_VM_STACK
-        /* USE_VM_STACK is defined (or not) in vm/vm_map.h */
-        bsd_args.flags |= MAP_STACK;      
+#ifdef VM_STACK
+	bsd_args.flags |= MAP_STACK;      
 #endif
 
 	/* The linux MAP_GROWSDOWN option does not limit auto
-	   growth of the region.  Linux mmap with this option
-	   takes as addr the inital BOS, and as len, the initial
-	   region size.  It can then grow down from addr without
-	   limit.  However, linux threads has an implicit internal
-	   limit to stack size of STACK_SIZE.  Its just not
-	   enforced explicitly in linux.  But, here we impose
-	   a limit of (STACK_SIZE - GUARD_SIZE) on the stack
-	   region, since we can do this with our mmap.
-
-	   Our mmap with MAP_STACK takes addr as the maximum
-	   downsize limit on BOS, and as len the max size of
-	   the region.  It them maps the top SGROWSIZ bytes,
-	   and autgrows the region down, up to the limit
-	   in addr.
-
-	   If we don't use the MAP_STACK option, the effect
-	   of this code is to allocate a stack region of a
-	   fixed size of (STACK_SIZE - GUARD_SIZE).
-	*/
+	 * growth of the region.  Linux mmap with this option
+	 * takes as addr the inital BOS, and as len, the initial
+	 * region size.  It can then grow down from addr without
+	 * limit.  However, linux threads has an implicit internal
+	 * limit to stack size of STACK_SIZE.  Its just not
+	 * enforced explicitly in linux.  But, here we impose
+	 * a limit of (STACK_SIZE - GUARD_SIZE) on the stack
+	 * region, since we can do this with our mmap.
+	 *
+	 * Our mmap with MAP_STACK takes addr as the maximum
+	 * downsize limit on BOS, and as len the max size of
+	 * the region.  It them maps the top SGROWSIZ bytes,
+	 * and autgrows the region down, up to the limit
+	 * in addr.
+	 *
+	 * If we don't use the MAP_STACK option, the effect
+	 * of this code is to allocate a stack region of a
+	 * fixed size of (STACK_SIZE - GUARD_SIZE).
+	 */
 
 	/* This gives us TOS */
-        bsd_args.addr = linux_args.addr + linux_args.len;
+	bsd_args.addr = linux_args.addr + linux_args.len;
 
 	/* This gives us our maximum stack size */
 	if (linux_args.len > STACK_SIZE - GUARD_SIZE)
@@ -735,15 +734,15 @@ linux_mmap(struct proc *p, struct linux_mmap_args *args)
 	    bsd_args.len  = STACK_SIZE - GUARD_SIZE;
 
 	/* This gives us a new BOS.  If we're using VM_STACK, then
-	   mmap will just map the top SGROWSIZ bytes, and let
-	   the stack grow down to the limit at BOS.  If we're
-	   not using VM_STACK we map the full stack, since we
-	   don't have a way to autogrow it.
-	*/
+	 * mmap will just map the top SGROWSIZ bytes, and let
+	 * the stack grow down to the limit at BOS.  If we're
+	 * not using VM_STACK we map the full stack, since we
+	 * don't have a way to autogrow it.
+	 */
 	bsd_args.addr -= bsd_args.len;
 
     } else {
-        bsd_args.addr = linux_args.addr;
+	bsd_args.addr = linux_args.addr;
 	bsd_args.len  = linux_args.len;
     }
 #endif /* COMPAT_LINUX_THREADS */
@@ -977,11 +976,11 @@ linux_waitpid(struct proc *p, struct linux_waitpid_args *args)
     tmp.options = args->options;
 #else
     /* This filters out the linux option _WCLONE.  I don't
-       think we need it, but I could be wrong.  If we need
-       it, we need to fix wait4, since it will give us an
-       error return of EINVAL if we pass in _WCLONE, and
-       of course, it won't do anything with it.
-    */
+     * think we need it, but I could be wrong.  If we need
+     * it, we need to fix wait4, since it will give us an
+     * error return of EINVAL if we pass in _WCLONE, and
+     * of course, it won't do anything with it.
+     */
     tmp.options = (args->options & (WNOHANG | WUNTRACED));
 #endif /* COMPAT_LINUX_THREADS */
     tmp.rusage = NULL;
@@ -990,7 +989,7 @@ linux_waitpid(struct proc *p, struct linux_waitpid_args *args)
 #ifndef COMPAT_LINUX_THREADS
 	return error;
 #else
-  	return error;
+	return error;
 #endif /* COMPAT_LINUX_THREADS */
     if (args->status) {
 	if (error = copyin(args->status, &tmpstat, sizeof(int)))
@@ -1028,11 +1027,11 @@ linux_wait4(struct proc *p, struct linux_wait4_args *args)
     tmp.options = args->options;
 #else
     /* This filters out the linux option _WCLONE.  I don't
-       think we need it, but I could be wrong.  If we need
-       it, we need to fix wait4, since it will give us an
-       error return of EINVAL if we pass in _WCLONE, and
-       of course, it won't do anything with it.
-    */
+     * think we need it, but I could be wrong.  If we need
+     * it, we need to fix wait4, since it will give us an
+     * error return of EINVAL if we pass in _WCLONE, and
+     * of course, it won't do anything with it.
+     */
     tmp.options = (args->options & (WNOHANG | WUNTRACED));
 #endif /* COMPAT_LINUX_THREADS */
     tmp.rusage = args->rusage;