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cpu_counter.h revision 1.5 
      1 /*	$NetBSD: cpu_counter.h,v 1.5 2007/07/07 17:38:27 tsutsui Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2000 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Bill Sommerfeld.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 #ifndef _I386_CPU_COUNTER_H_
     40 #define _I386_CPU_COUNTER_H_
     41 
     42 /*
     43  * Machine-specific support for CPU counter.
     44  */
     45 
     46 #include <machine/cpu.h>
     47 #include <machine/cpufunc.h>
     48 #include <machine/specialreg.h>
     49 
     50 #include "opt_cputype.h"
     51 
     52 #ifdef _KERNEL
     53 
     54 #include <x86/cpu_counter.h>
     55 
     56 static __inline int
     57 cpu_hascounter(void)
     58 {
     59 
     60 #if defined(I586_CPU) || defined(I686_CPU)
     61 	/*
     62 	 * Note that:
     63 	 * 1) Intel documentation is very specific that code *must* test
     64 	 * the CPU feature flag, even if you "know" that a particular
     65 	 * rev of the hardware supports it.
     66 	 * 2) We know that the TSC is busted on some Cyrix CPU in that if
     67 	 * you execute "hlt" when in powersave mode, TSC stops counting,
     68 	 * even though the CPU clock crystal is still ticking (it always has to).
     69 	 */
     70 	return (cpu_feature & CPUID_TSC) != 0;
     71 #else
     72 	return 0;
     73 #endif
     74 }
     75 
     76 #endif /* _KERNEL */
     77 
     78 #endif /* !_I386_CPU_COUNTER_H_ */
     79