 @@ -1,43 +1,43 @@
-/*	$NetBSD: tsc.c,v 1.41 2020/04/21 02:56:37 msaitoh Exp $	*/
+/*	$NetBSD: tsc.c,v 1.42 2020/04/23 20:38:33 ad Exp $	*/
 /*-
- * Copyright (c) 2008 The NetBSD Foundation, Inc.
+ * Copyright (c) 2008, 2020 The NetBSD Foundation, Inc.
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: tsc.c,v 1.41 2020/04/21 02:56:37 msaitoh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: tsc.c,v 1.42 2020/04/23 20:38:33 ad Exp $");
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/time.h>
 #include <sys/timetc.h>
 #include <sys/lwp.h>
 #include <sys/atomic.h>
 #include <sys/kernel.h>
 #include <sys/cpu.h>
 #include <sys/xcall.h>
 #include <machine/cpu_counter.h>
 #include <machine/cpuvar.h>
 @@ -219,33 +219,37 @@ tsc_read_bp(struct cpu_info *ci, uint64_
 		x86_pause();
+	}
 	if (tsc_sync_cpu != NULL) {
 		panic("tsc_sync_bp: 2");
+	}
 	*bptscp = bptsc;
 	*aptscp = tsc_sync_val;
+}
 void
 tsc_sync_bp(struct cpu_info *ci)
+{
-	uint64_t bptsc, aptsc;
+	int64_t bptsc, aptsc, bsum = 0, asum = 0;
 	tsc_read_bp(ci, &bptsc, &aptsc); /* discarded - cache effects */
-	tsc_read_bp(ci, &bptsc, &aptsc);
+	for (int i = 0; i < 8; i++) {
 		tsc_read_bp(ci, &bptsc, &aptsc);
 		bsum += bptsc;
 		asum += aptsc;
+	}
 	/* Compute final value to adjust for skew. */
-	ci->ci_data.cpu_cc_skew = bptsc - aptsc;
+	ci->ci_data.cpu_cc_skew = (bsum - asum) >> 3;
+}
 /*
  * Called during startup of AP, by the AP itself.  Interrupts are
  * disabled on entry.
  */
 static void
 tsc_post_ap(struct cpu_info *ci)
+{
 	uint64_t tsc;
 	/* Wait for go-ahead from primary. */
 	while ((ci->ci_flags & CPUF_SYNCTSC) == 0) {
 @@ -260,27 +264,29 @@ tsc_post_ap(struct cpu_info *ci)
 	/* Post result.  Ensure the whole value goes out atomically. */
 	(void)atomic_swap_64(&tsc_sync_val, tsc);
 	if (atomic_swap_ptr(&tsc_sync_cpu, NULL) != ci) {
 		panic("tsc_sync_ap");
+	}
+}
 void
 tsc_sync_ap(struct cpu_info *ci)
+{
 	tsc_post_ap(ci);
-	tsc_post_ap(ci);
+	for (int i = 0; i < 8; i++) {
 		tsc_post_ap(ci);
+	}
+}
 static void
 tsc_apply_cpu(void *arg1, void *arg2)
+{
 	bool enable = arg1 != NULL;
 	if (enable) {
 		lcr4(rcr4() & ~CR4_TSD);
 	} else {
 		lcr4(rcr4() | CR4_TSD);
+	}
+}