xref: /illumos-gate/usr/src/lib/libc/port/gen/getisax.c (revision dd72704bd9e794056c558153663c739e2012d721)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 /*
27  * Copyright (c) 2012, Joyent, Inc.  All rights reserved.
28  * Copyright 2022 Oxide Computer Company
29  */
30 
31 #pragma weak _getisax = getisax
32 
33 #include "lint.h"
34 #include <sys/types.h>
35 #include <sys/auxv.h>
36 
37 extern long ___getauxval(int type);
38 
39 /*
40  * Return the 'hwcap' vector of bits in the AT_SUN_HWCAP and AT_SUN_HWCAP2 aux
41  * vector entries. Therefore there are two words of bits here.
42  *
43  * As a convenience, the routine returns the maximum number of array alements
44  * that may contain non-zero values.
45  */
46 uint_t
47 getisax(uint32_t *array, uint_t n)
48 {
49 	int i;
50 	static uint32_t auxv_hwcap;
51 	static uint32_t auxv_hwcap_2;
52 	static uint32_t auxv_hwcap_3;
53 
54 	if (auxv_hwcap == 0) {
55 		auxv_hwcap = (uint32_t)___getauxval(AT_SUN_HWCAP);
56 		auxv_hwcap_2 = (uint32_t)___getauxval(AT_SUN_HWCAP2);
57 		auxv_hwcap_3 = (uint32_t)___getauxval(AT_SUN_HWCAP3);
58 	}
59 
60 	if (n > 0) {
61 		if (n >= 1)
62 			array[0] = auxv_hwcap;
63 		if (n >= 2)
64 			array[1] = auxv_hwcap_2;
65 		if (n >= 3)
66 			array[2] = auxv_hwcap_3;
67 		for (i = 3; i < n; i++)
68 			array[i] = 0;
69 	}
70 
71 	if (auxv_hwcap == 0) {
72 		return (0);
73 	}
74 
75 	return (n >= 3 ? 3 : n);
76 }
77