svn commit: r219679 - head/sys/i386/include

[Jung-uk Kim]

Author: jkim
Date: Tue Mar 15 21:45:10 2011
New Revision: 219679
URL: http://svn.freebsd.org/changeset/base/219679

Log:
  Partially revert r219672.  After r198295, kernel need to seed randomness as
  soon as possible for stack protector.  However, dummy timecounter does not
  have enough entropy and we don't need to sacrifice Pentium class and later.
  
  Pointed out by:	Maxim Dounin (mdounin at mdounin dot ru)

Modified:
  head/sys/i386/include/cpu.h

Modified: head/sys/i386/include/cpu.h
==============================================================================
--- head/sys/i386/include/cpu.h	Tue Mar 15 21:34:10 2011	(r219678)
+++ head/sys/i386/include/cpu.h	Tue Mar 15 21:45:10 2011	(r219679)
@@ -69,10 +69,14 @@ void	swi_vm(void *);
 static __inline uint64_t
 get_cyclecount(void)
 {
+#if defined(I486_CPU) || defined(KLD_MODULE)
 	struct bintime bt;
 
 	binuptime(&bt);
 	return ((uint64_t)bt.sec << 56 | bt.frac >> 8);
+#else
+	return (rdtsc());
+#endif
 }
 
 #endif