timecounting: deprecate time_second(9), time_uptime(9)

time_second(9) has been replaced in the kernel by gettime(9).
time_uptime(9) has been replaced in the kernel by getuptime(9).

New code should use the replacement interfaces.  They do not suffer
from the split-read problem inherent to the time_* variables on 32-bit
platforms.

The variables remain in sys/kern/kern_tc.c for use via kvm(3) when
examining kernel core dumps.

This commit completes the deprecation process:

- Remove the extern'd definitions for time_second and time_uptime
  from sys/time.h.
- Replace manpage cross-references to time_second(9)/time_uptime(9)
  with references to microtime(9) or a related interface.
- Move the time_second.9 manpage to the attic.

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

ok kettenis@

2 files changed, 6 insertions, 5 deletions

diff --git a/sys/kern/kern_tc.c b/sys/kern/kern_tc.c
index 54d50b1a6f7..96bc4b952c8 100644
--- a/sys/kern/kern_tc.c
+++ b/sys/kern/kern_tc.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_tc.c,v 1.58 2020/06/22 21:16:07 cheloha Exp $ */
+/*	$OpenBSD: kern_tc.c,v 1.59 2020/06/26 18:48:31 cheloha Exp $ */
 
 /*
  * Copyright (c) 2000 Poul-Henning Kamp <phk@FreeBSD.org>
@@ -113,6 +113,10 @@ static struct timehands *volatile timehands = &th0;		/* [w] */
 struct timecounter *timecounter = &dummy_timecounter;		/* [t] */
 static SLIST_HEAD(, timecounter) tc_list = SLIST_HEAD_INITIALIZER(tc_list);
 
+/*
+ * These are updated from tc_windup().  They are useful when
+ * examining kernel core dumps.
+ */
 volatile time_t time_second = 1;
 volatile time_t time_uptime = 0;
 
diff --git a/sys/sys/time.h b/sys/sys/time.h
index 3128a9cca23..32d3dd10364 100644
--- a/sys/sys/time.h
+++ b/sys/sys/time.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: time.h,v 1.53 2020/06/26 03:21:46 jsg Exp $	*/
+/*	$OpenBSD: time.h,v 1.54 2020/06/26 18:48:31 cheloha Exp $	*/
 /*	$NetBSD: time.h,v 1.18 1996/04/23 10:29:33 mycroft Exp $	*/
 
 /*
@@ -250,9 +250,6 @@ TIMEVAL_TO_BINTIME(const struct timeval *tv, struct bintime *bt)
 	bt->frac = (uint64_t)tv->tv_usec * (uint64_t)18446744073709ULL;
 }
 
-extern volatile time_t time_second;	/* Seconds since epoch, wall time. */
-extern volatile time_t time_uptime;	/* Seconds since reboot. */
-
 /*
  * Functions for looking at our clocks: [get]{bin,nano,micro}[boot|up]time()
  *