gtmr.c.broken_cntv.20181112.diff

cvs -q diff -aup gtmr.c
Index: gtmr.c
===================================================================
RCS file: /src/cvs/cvsroot-netbsd/src/sys/arch/arm/cortex/gtmr.c,v
retrieving revision 1.37
diff -a -u -p -r1.37 gtmr.c
--- gtmr.c	30 Oct 2018 10:38:11 -0000	1.37
+++ gtmr.c	31 Oct 2018 06:13:06 -0000
@@ -315,6 +315,34 @@ gtmr_intr(void *arg)
 	return 1;
 }
 
+void gtmr_fixup(void); /* if you want fixup from ddb, "call gtmr_fixup" */
+
+void
+gtmr_fixup(void)
+{
+	struct gtmr_softc * const sc = &gtmr_sc;
+	uint64_t now;
+	int s;
+
+	if (sc->sc_autoinc == 0)
+		return;
+
+	s = splclock();
+
+	now = gtmr_read_cntvct(sc);
+	if (now < curcpu()->ci_lastintr) {
+		printf("cpu%d: detect cntvc was rollbacked: "
+		    "0x%"PRIx64" -> 0x%"PRIx64" (%+"PRId64"). fixup\n",
+		    curcpu()->ci_index,
+		    curcpu()->ci_lastintr, now, now - curcpu()->ci_lastintr);
+
+		curcpu()->ci_lastintr = now;
+		gtmr_cntv_tval_write(sc->sc_autoinc);
+	}
+
+	splx(s);
+}
+
 void
 setstatclockrate(int newhz)
 {
@@ -325,5 +353,6 @@ gtmr_get_timecount(struct timecounter *t
 {
 	struct gtmr_softc * const sc = tc->tc_priv;
 	arm_isb();	// we want the time NOW, not some instructions later.
+	gtmr_fixup();
 	return (u_int) gtmr_read_cntvct(sc);
 }