xref: /netbsd-src/sys/arch/arm/include/lwp_private.h (revision 16543c49052c820334cffc5c69b2afde18f02458)
1 /*	$NetBSD: lwp_private.h,v 1.1 2024/11/30 01:04:07 christos Exp $	*/
2 
3 /*-
4  * Copyright (c) 2001, 2002 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Klaus Klein and by Jason R. Thorpe of Wasabi Systems, Inc.
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  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 #ifndef _ARM_LWP_PRIVATE_H_
33 #define _ARM_LWP_PRIVATE_H_
34 
35 #include <sys/cdefs.h>
36 #include <sys/tls.h>
37 
38 #include <lwp.h>
39 
40 #if defined(__aarch64__)
41 
42 __BEGIN_DECLS
43 static __inline void *
44 __lwp_getprivate_fast(void)
45 {
46 	void *__tpidr;
47 	__asm __volatile("mrs\t%0, tpidr_el0" : "=r"(__tpidr));
48 	return __tpidr;
49 }
50 __END_DECLS
51 
52 #elif defined(__arm__)
53 
54 #if defined(__thumb__) && !defined(_ARM_ARCH_T2)
55 #include <arm/eabi.h>
56 #endif
57 
58 __BEGIN_DECLS
59 static __inline void *
60 __lwp_getprivate_fast(void)
61 {
62 #if !defined(__thumb__) || defined(_ARM_ARCH_T2)
63 	void *rv;
64 	__asm("mrc p15, 0, %0, c13, c0, 3" : "=r"(rv));
65 	if (__predict_true(rv))
66 		return rv;
67 	/*
68 	 * Some ARM cores are broken and don't raise an undefined fault when an
69 	 * unrecogized mrc instruction is encountered, but just return zero.
70 	 * To do deal with that, if we get a zero we (re-)fetch the value using
71 	 * syscall.
72 	 */
73 	return _lwp_getprivate();
74 #else
75 	return __aeabi_read_tp();
76 #endif /* !__thumb__ || _ARM_ARCH_T2 */
77 }
78 __END_DECLS
79 #endif
80 
81 #endif	/* !_ARM_LWP_PRIVATE_H_ */
82