xref: /freebsd/sys/amd64/amd64/initcpu.c (revision 77b7cdf1999ee965ad494fddd184b18f532ac91a)
1 /*
2  * Copyright (c) KATO Takenori, 1997, 1998.
3  *
4  * All rights reserved.  Unpublished rights reserved under the copyright
5  * laws of Japan.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer as
13  *    the first lines of this file unmodified.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28  *
29  * $FreeBSD$
30  */
31 
32 #include "opt_cpu.h"
33 
34 #include <sys/param.h>
35 #include <sys/kernel.h>
36 #include <sys/systm.h>
37 #include <sys/sysctl.h>
38 
39 #include <machine/cputypes.h>
40 #include <machine/md_var.h>
41 #include <machine/specialreg.h>
42 
43 void initializecpu(void);
44 
45 static int	hw_instruction_sse;
46 SYSCTL_INT(_hw, OID_AUTO, instruction_sse, CTLFLAG_RD,
47     &hw_instruction_sse, 0, "SIMD/MMX2 instructions available in CPU");
48 
49 int	cpu;			/* Are we 386, 386sx, 486, etc? */
50 u_int	cpu_feature;		/* Feature flags */
51 u_int	cpu_high;		/* Highest arg to CPUID */
52 u_int	cpu_id;			/* Stepping ID */
53 u_int	cpu_procinfo;		/* HyperThreading Info / Brand Index / CLFUSH */
54 char	cpu_vendor[20];		/* CPU Origin code */
55 u_int	cpu_fxsr;		/* SSE enabled */
56 
57 /*
58  * Initialize CR4 (Control register 4) to enable SSE instructions.
59  */
60 void
61 enable_sse(void)
62 {
63 	if ((cpu_feature & CPUID_XMM) && (cpu_feature & CPUID_FXSR)) {
64 		load_cr4(rcr4() | CR4_FXSR | CR4_XMM);
65 		cpu_fxsr = hw_instruction_sse = 1;
66 	}
67 }
68 
69 void
70 initializecpu(void)
71 {
72 
73 	switch (cpu) {
74 	default:
75 		break;
76 	}
77 	enable_sse();
78 }
79