kernel: use gettime(9)/getuptime(9) in lieu of time_second(9)/time_uptime(9)

time_second(9) and time_uptime(9) are widely used in the kernel to
quickly get the system UTC or system uptime as a time_t.  However,
time_t is 64-bit everywhere, so it is not generally safe to use them
on 32-bit platforms: you have a split-read problem if your hardware
cannot perform atomic 64-bit reads.

This patch replaces time_second(9) with gettime(9), a safer successor
interface, throughout the kernel.  Similarly, time_uptime(9) is replaced
with getuptime(9).

There is a performance cost on 32-bit platforms in exchange for
eliminating the split-read problem: instead of two register reads you
now have a lockless read loop to pull the values from the timehands.
This is really not *too* bad in the grand scheme of things, but
compared to what we were doing before it is several times slower.

There is no performance cost on 64-bit (__LP64__) platforms.

With input from visa@, dlg@, and tedu@.

Several bugs squashed by visa@.

ok kettenis@

6 files changed, 29 insertions, 29 deletions

diff --git a/sys/netinet/if_ether.c b/sys/netinet/if_ether.c
index f950dbebc33..fceeffc3e10 100644
--- a/sys/netinet/if_ether.c
+++ b/sys/netinet/if_ether.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_ether.c,v 1.242 2019/11/07 11:23:23 krw Exp $	*/
+/*	$OpenBSD: if_ether.c,v 1.243 2020/06/24 22:03:43 cheloha Exp $	*/
 /*	$NetBSD: if_ether.c,v 1.31 1996/05/11 12:59:58 mycroft Exp $	*/
 
 /*
@@ -120,7 +120,7 @@ arptimer(void *arg)
 	LIST_FOREACH_SAFE(la, &arp_list, la_list, nla) {
 		struct rtentry *rt = la->la_rt;
 
-		if (rt->rt_expire && rt->rt_expire < time_uptime)
+		if (rt->rt_expire && rt->rt_expire < getuptime())
 			arptfree(rt); /* timer has expired; clear */
 	}
 	NET_UNLOCK();
@@ -192,7 +192,7 @@ arp_rtrequest(struct ifnet *ifp, int req, struct rtentry *rt)
 		la->la_rt = rt;
 		rt->rt_flags |= RTF_LLINFO;
 		if ((rt->rt_flags & RTF_LOCAL) == 0)
-			rt->rt_expire = time_uptime;
+			rt->rt_expire = getuptime();
 		LIST_INSERT_HEAD(&arp_list, la, la_list);
 		break;
 
@@ -320,7 +320,7 @@ arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
 	rt = rt_getll(rt0);
 
 	if (ISSET(rt->rt_flags, RTF_REJECT) &&
-	    (rt->rt_expire == 0 || rt->rt_expire > time_uptime )) {
+	    (rt->rt_expire == 0 || rt->rt_expire > getuptime() )) {
 		m_freem(m);
 		return (rt == rt0 ? EHOSTDOWN : EHOSTUNREACH);
 	}
@@ -348,15 +348,15 @@ arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
 	 * Check the address family and length is valid, the address
 	 * is resolved; otherwise, try to resolve.
 	 */
-	if ((rt->rt_expire == 0 || rt->rt_expire > time_uptime) &&
+	if ((rt->rt_expire == 0 || rt->rt_expire > getuptime()) &&
 	    sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {
 		memcpy(desten, LLADDR(sdl), sdl->sdl_alen);
 
 		/* refresh ARP entry when timeout gets close */
 		if (rt->rt_expire != 0 &&
-		    rt->rt_expire - arpt_keep / 8 < time_uptime &&
-		    la->la_refreshed + 30 < time_uptime) {
-			la->la_refreshed = time_uptime;
+		    rt->rt_expire - arpt_keep / 8 < getuptime() &&
+		    la->la_refreshed + 30 < getuptime()) {
+			la->la_refreshed = getuptime();
 			arprequest(ifp,
 			    &satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr,
 			    &satosin(dst)->sin_addr.s_addr,
@@ -396,13 +396,13 @@ arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
 		/* This should never happen. (Should it? -gwr) */
 		printf("%s: unresolved and rt_expire == 0\n", __func__);
 		/* Set expiration time to now (expired). */
-		rt->rt_expire = time_uptime;
+		rt->rt_expire = getuptime();
 	}
 #endif
 	if (rt->rt_expire) {
 		rt->rt_flags &= ~RTF_REJECT;
-		if (la->la_asked == 0 || rt->rt_expire != time_uptime) {
-			rt->rt_expire = time_uptime;
+		if (la->la_asked == 0 || rt->rt_expire != getuptime()) {
+			rt->rt_expire = getuptime();
 			if (la->la_asked++ < arp_maxtries)
 				arprequest(ifp,
 				    &satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr,
@@ -661,7 +661,7 @@ arpcache(struct ifnet *ifp, struct ether_arp *ea, struct rtentry *rt)
 	sdl->sdl_alen = sizeof(ea->arp_sha);
 	memcpy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha));
 	if (rt->rt_expire)
-		rt->rt_expire = time_uptime + arpt_keep;
+		rt->rt_expire = getuptime() + arpt_keep;
 	rt->rt_flags &= ~RTF_REJECT;
 
 	/* Notify userland that an ARP resolution has been done. */
diff --git a/sys/netinet/ip_ipsp.c b/sys/netinet/ip_ipsp.c
index 8405bb5c18f..1755056a647 100644
--- a/sys/netinet/ip_ipsp.c
+++ b/sys/netinet/ip_ipsp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip_ipsp.c,v 1.235 2020/04/23 19:38:08 tobhe Exp $	*/
+/*	$OpenBSD: ip_ipsp.c,v 1.236 2020/06/24 22:03:43 cheloha Exp $	*/
 /*
  * The authors of this code are John Ioannidis (ji@tla.org),
  * Angelos D. Keromytis (kermit@csd.uch.gr),
@@ -708,7 +708,7 @@ puttdb(struct tdb *tdbp)
 		ipsecstat_inc(ipsec_tunnels);
 #endif /* IPSEC */
 
-	ipsec_last_added = time_uptime;
+	ipsec_last_added = getuptime();
 }
 
 void
@@ -804,7 +804,7 @@ tdb_alloc(u_int rdomain)
 	TAILQ_INIT(&tdbp->tdb_policy_head);
 
 	/* Record establishment time. */
-	tdbp->tdb_established = time_second;
+	tdbp->tdb_established = gettime();
 
 	/* Save routing domain */
 	tdbp->tdb_rdomain = rdomain;
diff --git a/sys/netinet/ip_output.c b/sys/netinet/ip_output.c
index 2fca6974b35..788f47da48d 100644
--- a/sys/netinet/ip_output.c
+++ b/sys/netinet/ip_output.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip_output.c,v 1.356 2020/03/06 10:40:13 tobhe Exp $	*/
+/*	$OpenBSD: ip_output.c,v 1.357 2020/06/24 22:03:43 cheloha Exp $	*/
 /*	$NetBSD: ip_output.c,v 1.28 1996/02/13 23:43:07 christos Exp $	*/
 
 /*
@@ -589,7 +589,7 @@ ip_output_ipsec_send(struct tdb *tdb, struct mbuf *m, struct route *ro, int fwd)
 	ip = mtod(m, struct ip *);
 	if (ip_mtudisc && (ip->ip_off & htons(IP_DF)) && tdb->tdb_mtu &&
 	    ntohs(ip->ip_len) > tdb->tdb_mtu &&
-	    tdb->tdb_mtutimeout > time_second) {
+	    tdb->tdb_mtutimeout > gettime()) {
 		struct rtentry *rt = NULL;
 		int rt_mtucloned = 0;
 		int transportmode = 0;
diff --git a/sys/netinet/ip_spd.c b/sys/netinet/ip_spd.c
index 727cad81994..9487ee4893d 100644
--- a/sys/netinet/ip_spd.c
+++ b/sys/netinet/ip_spd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ip_spd.c,v 1.101 2019/12/10 17:58:54 tobhe Exp $ */
+/* $OpenBSD: ip_spd.c,v 1.102 2020/06/24 22:03:43 cheloha Exp $ */
 /*
  * The author of this code is Angelos D. Keromytis (angelos@cis.upenn.edu)
  *
@@ -438,7 +438,7 @@ ipsp_spd_lookup(struct mbuf *m, int af, int hlen, int *error, int direction,
 		if (ipo->ipo_last_searched <= ipsec_last_added)	{
 			/* "Touch" the entry. */
 			if (dignore == 0)
-				ipo->ipo_last_searched = time_uptime;
+				ipo->ipo_last_searched = getuptime();
 
 			/* Find an appropriate SA from the existing ones. */
 			ipo->ipo_tdb =
@@ -560,7 +560,7 @@ ipsp_spd_lookup(struct mbuf *m, int af, int hlen, int *error, int direction,
 		/* Find whether there exists an appropriate SA. */
 		if (ipo->ipo_last_searched <= ipsec_last_added)	{
 			if (dignore == 0)
-				ipo->ipo_last_searched = time_uptime;
+				ipo->ipo_last_searched = getuptime();
 
 			ipo->ipo_tdb =
 			    gettdbbysrc(rdomain,
diff --git a/sys/netinet/ipsec_input.c b/sys/netinet/ipsec_input.c
index 7303c3cb303..050dc7b1128 100644
--- a/sys/netinet/ipsec_input.c
+++ b/sys/netinet/ipsec_input.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ipsec_input.c,v 1.170 2020/04/23 19:38:08 tobhe Exp $	*/
+/*	$OpenBSD: ipsec_input.c,v 1.171 2020/06/24 22:03:43 cheloha Exp $	*/
 /*
  * The authors of this code are John Ioannidis (ji@tla.org),
  * Angelos D. Keromytis (kermit@csd.uch.gr) and
@@ -316,7 +316,7 @@ ipsec_common_input(struct mbuf *m, int skip, int protoff, int af, int sproto,
 
 	/* Register first use, setup expiration timer. */
 	if (tdbp->tdb_first_use == 0) {
-		tdbp->tdb_first_use = time_second;
+		tdbp->tdb_first_use = gettime();
 		if (tdbp->tdb_flags & TDBF_FIRSTUSE)
 			timeout_add_sec(&tdbp->tdb_first_tmo,
 			    tdbp->tdb_exp_first_use);
@@ -453,7 +453,7 @@ ipsec_common_input_cb(struct mbuf *m, struct tdb *tdbp, int skip, int protoff)
 	af = tdbp->tdb_dst.sa.sa_family;
 	sproto = tdbp->tdb_sproto;
 
-	tdbp->tdb_last_used = time_second;
+	tdbp->tdb_last_used = gettime();
 
 	/* Sanity check */
 	if (m == NULL) {
@@ -984,7 +984,7 @@ ipsec_common_ctlinput(u_int rdomain, int cmd, struct sockaddr *sa,
 
 			/* Store adjusted MTU in tdb */
 			tdbp->tdb_mtu = mtu;
-			tdbp->tdb_mtutimeout = time_second +
+			tdbp->tdb_mtutimeout = gettime() +
 			    ip_mtudisc_timeout;
 			DPRINTF(("%s: spi %08x mtu %d adjust %ld\n", __func__,
 			    ntohl(tdbp->tdb_spi), tdbp->tdb_mtu,
@@ -1039,7 +1039,7 @@ udpencap_ctlinput(int cmd, struct sockaddr *sa, u_int rdomain, void *v)
 			if ((adjust = ipsec_hdrsz(tdbp)) != -1) {
 				/* Store adjusted MTU in tdb */
 				tdbp->tdb_mtu = mtu - adjust;
-				tdbp->tdb_mtutimeout = time_second +
+				tdbp->tdb_mtutimeout = gettime() +
 				    ip_mtudisc_timeout;
 				DPRINTF(("%s: spi %08x mtu %d adjust %ld\n",
 				    __func__,
diff --git a/sys/netinet/ipsec_output.c b/sys/netinet/ipsec_output.c
index c5a13312f67..ed4551d1f47 100644
--- a/sys/netinet/ipsec_output.c
+++ b/sys/netinet/ipsec_output.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ipsec_output.c,v 1.76 2020/04/23 19:38:09 tobhe Exp $ */
+/*	$OpenBSD: ipsec_output.c,v 1.77 2020/06/24 22:03:43 cheloha Exp $ */
 /*
  * The author of this code is Angelos D. Keromytis (angelos@cis.upenn.edu)
  *
@@ -135,7 +135,7 @@ ipsp_process_packet(struct mbuf *m, struct tdb *tdb, int af, int tunalready)
 	 * Register first use if applicable, setup relevant expiration timer.
 	 */
 	if (tdb->tdb_first_use == 0) {
-		tdb->tdb_first_use = time_second;
+		tdb->tdb_first_use = gettime();
 		if (tdb->tdb_flags & TDBF_FIRSTUSE)
 			timeout_add_sec(&tdb->tdb_first_tmo,
 			    tdb->tdb_exp_first_use);
@@ -474,7 +474,7 @@ ipsp_process_done(struct mbuf *m, struct tdb *tdb)
 	struct m_tag *mtag;
 	int roff, error;
 
-	tdb->tdb_last_used = time_second;
+	tdb->tdb_last_used = gettime();
 
 	if ((tdb->tdb_flags & TDBF_UDPENCAP) != 0) {
 		struct mbuf *mi;
@@ -698,7 +698,7 @@ ipsec_adjust_mtu(struct mbuf *m, u_int32_t mtu)
 
 		mtu -= adjust;
 		tdbp->tdb_mtu = mtu;
-		tdbp->tdb_mtutimeout = time_second + ip_mtudisc_timeout;
+		tdbp->tdb_mtutimeout = gettime() + ip_mtudisc_timeout;
 		DPRINTF(("ipsec_adjust_mtu: "
 		    "spi %08x mtu %d adjust %ld mbuf %p\n",
 		    ntohl(tdbp->tdb_spi), tdbp->tdb_mtu,