xref: /freebsd/lib/libc/aarch64/string/memset_resolver.c (revision a689bfa4e25af8307709dc12f75b0e02a65abf18)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2026 Arm Ltd
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 #include <sys/types.h>
28 
29 #include <machine/armreg.h>
30 #include <machine/ifunc.h>
31 
32 #include <elf.h>
33 
34 void *__memset_aarch64(void *, int, size_t);
35 void *__memset_aarch64_zva64(void *, int, size_t);
36 void *__memset_aarch64_mops(void *, int, size_t);
37 
38 DEFINE_UIFUNC(, void *, memset, (void *, int, size_t))
39 {
40 	uint64_t dczid;
41 
42 	if (ifunc_arg->_hwcap2 & HWCAP2_MOPS)
43 		return (__memset_aarch64_mops);
44 
45 	/*
46 	 * Check for the DC ZVA instruction, and it will
47 	 * zero 64 bytes (4 * 4byte words).
48 	 */
49 	dczid = READ_SPECIALREG(dczid_el0);
50 	if ((dczid & DCZID_DZP) == 0 && DCZID_BS_SIZE(dczid) == 4)
51 		return (__memset_aarch64_zva64);
52 
53 	return (__memset_aarch64);
54 }
55 
56