Module Name: src
Committed By: riastradh
Date: Sun Jul 17 11:31:07 UTC 2022
Modified Files:
src/sys/dev/wscons: wsdisplay_vcons.c
Log Message:
wsdisplay(4): Insert memory barriers for scr_dirty synchronization.
Otherwise vcons_update_screen in vcons_softintr might attempt to draw
stale data from the buffers on the screen.
To generate a diff of this commit:
cvs rdiff -u -r1.58 -r1.59 src/sys/dev/wscons/wsdisplay_vcons.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/dev/wscons/wsdisplay_vcons.c
diff -u src/sys/dev/wscons/wsdisplay_vcons.c:1.58 src/sys/dev/wscons/wsdisplay_vcons.c:1.59
--- src/sys/dev/wscons/wsdisplay_vcons.c:1.58 Sun Jul 17 11:30:27 2022
+++ src/sys/dev/wscons/wsdisplay_vcons.c Sun Jul 17 11:31:07 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: wsdisplay_vcons.c,v 1.58 2022/07/17 11:30:27 riastradh Exp $ */
+/* $NetBSD: wsdisplay_vcons.c,v 1.59 2022/07/17 11:31:07 riastradh Exp $ */
/*-
* Copyright (c) 2005, 2006 Michael Lorenz
@@ -27,7 +27,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: wsdisplay_vcons.c,v 1.58 2022/07/17 11:30:27 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: wsdisplay_vcons.c,v 1.59 2022/07/17 11:31:07 riastradh Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -139,6 +139,7 @@ static inline void
vcons_dirty(struct vcons_screen *scr)
{
#ifdef VCONS_DRAW_INTR
+ membar_release();
atomic_inc_uint(&scr->scr_dirty);
#endif
}
@@ -1520,6 +1521,7 @@ vcons_softintr(void *cookie)
if (scr && vd->use_intr) {
if (!SCREEN_IS_BUSY(scr)) {
dirty = atomic_swap_uint(&scr->scr_dirty, 0);
+ membar_acquire();
if (vd->use_intr == 2) {
if ((scr->scr_flags & VCONS_NO_REDRAW) == 0) {
vd->use_intr = 1;
