SunOS uses trap 2 to clear cpu caches. From NetBSD via scottr and gwr.

diff --git a/sys/arch/sun3/sun3/trap.c b/sys/arch/sun3/sun3/trap.c
index f3eb4d0..a1a0f87 100644 (file)
--- a/sys/arch/sun3/sun3/trap.c
+++ b/sys/arch/sun3/sun3/trap.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: trap.c,v 1.15 1997/02/21 06:07:28 deraadt Exp $       */
+/*     $OpenBSD: trap.c,v 1.16 1997/04/08 17:30:23 briggs Exp $        */
 /*     $NetBSD: trap.c,v 1.63-1.65ish 1997/01/16 15:41:40 gwr Exp $    */
 
 /*
@@ -413,12 +413,16 @@ trap(type, code, v, frame)
        case T_TRAP15|T_USER:   /* SUN user trace trap */
 #ifdef COMPAT_SUNOS
                /*
-                * SunOS seems to use Trap #2 for some obscure fpu operations.
-                * So far, just ignore it, but DONT trap on it...
-                * (i.e. do not deliver a signal for it)
-                */
-               if (p->p_emul == &emul_sunos)
-                       goto douret;
+                * SunOS uses Trap #2 for a "CPU cache flush"
+                * Just flush the on-chip caches and return.
+                * XXX - Too bad NetBSD uses trap 2...
+                */
+               if (p->p_emul == &emul_sunos) {
+                       ICIA();
+                       DCIU();
+                       /* get out fast */
+                       return;
+               }
 #endif
                frame.f_sr &= ~PSL_T;
                sig = SIGTRAP;