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From: Jung-uk Kim <jkim@FreeBSD.org>
Date: Tue, 15 Mar 2011 19:47:20 +0000 (UTC)
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Subject: svn commit: r219676 - head/sys/x86/x86
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Author: jkim
Date: Tue Mar 15 19:47:20 2011
New Revision: 219676
URL: http://svn.freebsd.org/changeset/base/219676

Log:
  Do not let machdep.tsc_freq modify tsc_freq itself.  It is bad for i386 as
  it does not operate atomically.  Actually, it serves no purpose.
  
  Noticed by:	bde

Modified:
  head/sys/x86/x86/tsc.c

Modified: head/sys/x86/x86/tsc.c
==============================================================================
--- head/sys/x86/x86/tsc.c	Tue Mar 15 18:09:29 2011	(r219675)
+++ head/sys/x86/x86/tsc.c	Tue Mar 15 19:47:20 2011	(r219676)
@@ -263,12 +263,10 @@ sysctl_machdep_tsc_freq(SYSCTL_HANDLER_A
 
 	if (tsc_timecounter.tc_frequency == 0)
 		return (EOPNOTSUPP);
-	freq = tsc_freq;
+	freq = tsc_timecounter.tc_frequency;
 	error = sysctl_handle_64(oidp, &freq, 0, req);
-	if (error == 0 && req->newptr != NULL) {
-		tsc_freq = freq;
-		tsc_timecounter.tc_frequency = tsc_freq;
-	}
+	if (error == 0 && req->newptr != NULL)
+		tsc_timecounter.tc_frequency = freq;
 	return (error);
 }