From 505e9bd0945c239c487fc159a010be5d2d9bc647 Mon Sep 17 00:00:00 2001
From: mikeb <mikeb@openbsd.org>
Date: Wed, 17 Aug 2016 17:18:38 +0000
Subject: [PATCH] Replace hand rolled atomic bit operations and use MI ones
 from DRM

---
 sys/dev/pv/xen.c    | 15 +++++++--------
 sys/dev/pv/xenvar.h | 30 ++++++++++++------------------
 2 files changed, 19 insertions(+), 26 deletions(-)

diff --git a/sys/dev/pv/xen.c b/sys/dev/pv/xen.c
index f03d7459300..6841c05a761 100644
--- a/sys/dev/pv/xen.c
+++ b/sys/dev/pv/xen.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: xen.c,v 1.61 2016/08/05 18:31:21 mikeb Exp $	*/
+/*	$OpenBSD: xen.c,v 1.62 2016/08/17 17:18:38 mikeb Exp $	*/
 
 /*
  * Copyright (c) 2015 Mike Belopuhov
@@ -744,7 +744,7 @@ xen_intr_establish(evtchn_port_t port, xen_intr_handle_t *xih, int domain,
 	SLIST_INSERT_HEAD(&sc->sc_intrs, xi, xi_entry);
 
 	/* Mask the event port */
-	atomic_setbit_ptr(&sc->sc_ipg->evtchn_mask[0], xi->xi_port);
+	set_bit(xi->xi_port, &sc->sc_ipg->evtchn_mask[0]);
 
 #if defined(XEN_DEBUG) && disabled
 	memset(&es, 0, sizeof(es));
@@ -790,8 +790,8 @@ xen_intr_disestablish(xen_intr_handle_t xih)
 
 	taskq_destroy(xi->xi_taskq);
 
-	atomic_setbit_ptr(&sc->sc_ipg->evtchn_mask[0], xi->xi_port);
-	atomic_clearbit_ptr(&sc->sc_ipg->evtchn_pending[0], xi->xi_port);
+	set_bit(xi->xi_port, &sc->sc_ipg->evtchn_mask[0]);
+	clear_bit(xi->xi_port, &sc->sc_ipg->evtchn_pending[0]);
 
 	if (!xi->xi_noclose) {
 		ec.port = xi->xi_port;
@@ -820,8 +820,7 @@ xen_intr_enable(void)
 				printf("%s: unmasking port %u failed\n",
 				    sc->sc_dev.dv_xname, xi->xi_port);
 			virtio_membar_sync();
-			if (isset((char *)&sc->sc_ipg->evtchn_mask[0],
-			    xi->xi_port))
+			if (test_bit(xi->xi_port, &sc->sc_ipg->evtchn_mask[0]))
 				printf("%s: port %u is still masked\n",
 				    sc->sc_dev.dv_xname, xi->xi_port);
 		}
@@ -837,7 +836,7 @@ xen_intr_mask(xen_intr_handle_t xih)
 
 	if ((xi = xen_lookup_intsrc(sc, port)) != NULL) {
 		xi->xi_masked = 1;
-		atomic_setbit_ptr(&sc->sc_ipg->evtchn_mask[0], xi->xi_port);
+		set_bit(xi->xi_port, &sc->sc_ipg->evtchn_mask[0]);
 	}
 }
 
@@ -851,7 +850,7 @@ xen_intr_unmask(xen_intr_handle_t xih)
 
 	if ((xi = xen_lookup_intsrc(sc, port)) != NULL) {
 		xi->xi_masked = 0;
-		if (!isset((char *)&sc->sc_ipg->evtchn_mask[0], xi->xi_port))
+		if (!test_bit(xi->xi_port, &sc->sc_ipg->evtchn_mask[0]))
 			return (0);
 		eu.port = xi->xi_port;
 		return (xen_evtchn_hypercall(sc, EVTCHNOP_unmask, &eu,
diff --git a/sys/dev/pv/xenvar.h b/sys/dev/pv/xenvar.h
index 428002d6a72..980f5910b34 100644
--- a/sys/dev/pv/xenvar.h
+++ b/sys/dev/pv/xenvar.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: xenvar.h,v 1.35 2016/08/03 17:14:41 mikeb Exp $	*/
+/*	$OpenBSD: xenvar.h,v 1.36 2016/08/17 17:18:38 mikeb Exp $	*/
 
 /*
  * Copyright (c) 2015 Mike Belopuhov
@@ -143,28 +143,22 @@ struct xs_transaction {
 	struct xs_softc		*xst_sc;
 };
 
-static inline int
-atomic_setbit_ptr(volatile void *ptr, int bit)
+static __inline void
+clear_bit(u_int b, volatile void *p)
 {
-	int obit;
-
-	__asm__ __volatile__ ("lock btsl %2,%1; sbbl %0,%0" :
-	    "=r" (obit), "=m" (*(volatile long *)ptr) : "Ir" (bit) :
-	    "memory");
-
-	return (obit);
+	atomic_clearbits_int(((volatile u_int *)p) + (b >> 5), 1 << (b & 0x1f));
 }
 
-static inline int
-atomic_clearbit_ptr(volatile void *ptr, int bit)
+static __inline void
+set_bit(u_int b, volatile void *p)
 {
-	int obit;
-
-	__asm__ __volatile__ ("lock btrl %2,%1; sbbl %0,%0" :
-	    "=r" (obit), "=m" (*(volatile long *)ptr) : "Ir" (bit) :
-	    "memory");
+	atomic_setbits_int(((volatile u_int *)p) + (b >> 5), 1 << (b & 0x1f));
+}
 
-	return (obit);
+static __inline int
+test_bit(u_int b, volatile void *p)
+{
+	return !!(((volatile u_int *)p)[b >> 5] & (1 << (b & 0x1f)));
 }
 
 int	xs_cmd(struct xs_transaction *, int, const char *, struct iovec **,
-- 
2.20.1