xref: /netbsd-src/sys/arch/alpha/alpha/patch.c (revision 2d93273ebd9d1840d6d98e634f2f7a05b707a1b7)
1 /*	$NetBSD: patch.c,v 1.8 2023/11/21 22:19:12 thorpej Exp $	*/
2 
3 /*-
4  * Copyright (c) 2007, 2021 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Andrew Doran and Jason R. Thorpe.
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 /*
33  * Patch kernel code at boot time, depending on available CPU features
34  * and configuration.
35  */
36 
37 #include <sys/cdefs.h>
38 __KERNEL_RCSID(0, "$NetBSD: patch.c,v 1.8 2023/11/21 22:19:12 thorpej Exp $");
39 
40 #include "opt_multiprocessor.h"
41 
42 #include <sys/types.h>
43 #include <sys/systm.h>
44 #include <sys/lwp.h>
45 
46 #include <machine/cpu.h>
47 #include <machine/alpha.h>
48 #include <machine/intr.h>
49 
50 #include <machine/alpha_instruction.h>
51 
52 void	_membar_producer(void);
53 void	_membar_producer_end(void);
54 void	_membar_producer_mp(void);
55 void	_membar_producer_mp_end(void);
56 
57 void	_membar_sync(void);
58 void	_membar_sync_end(void);
59 void	_membar_sync_mp(void);
60 void	_membar_sync_mp_end(void);
61 
62 extern char alpha_copystr_bwx[], alpha_copystr_bwx_end[];
63 extern char alpha_copystr[], alpha_copystr_end[];
64 
65 #if defined(MULTIPROCESSOR)
66 extern uint32_t *lock_stub_patch_table[];
67 
68 static void
patch_lock_stubs(void)69 patch_lock_stubs(void)
70 {
71 	alpha_instruction insn = {
72 		.mem_format = {
73 			.opcode = op_special,
74 			.displacement = op_mb,
75 		},
76 	};
77 	int i, s;
78 
79 	s = splhigh();
80 
81 	for (i = 0; lock_stub_patch_table[i] != NULL; i++) {
82 		*lock_stub_patch_table[i] = insn.bits;
83 	}
84 	alpha_pal_imb();
85 
86 	splx(s);
87 }
88 #endif /* MULTIPROCESSOR */
89 
90 static void
patchfunc(void * from_s,void * from_e,void * to_s,void * to_e)91 patchfunc(void *from_s, void *from_e, void *to_s, void *to_e)
92 {
93 	int s;
94 
95 	s = splhigh();
96 
97 	if ((uintptr_t)from_e - (uintptr_t)from_s !=
98 	    (uintptr_t)to_e - (uintptr_t)to_s)
99 	    	panic("patchfunc: sizes do not match (from=%p)", from_s);
100 
101 	memcpy(to_s, from_s, (uintptr_t)to_e - (uintptr_t)to_s);
102 	alpha_pal_imb();
103 
104 	splx(s);
105 }
106 
107 void
alpha_patch(bool is_mp)108 alpha_patch(bool is_mp)
109 {
110 
111 	/*
112 	 * We allow this function to be called multiple times
113 	 * (there is no harm in doing so), so long as other
114 	 * CPUs have not yet actually hatched to start running
115 	 * kernel code.
116 	 */
117 
118 	if (cpu_amask & ALPHA_AMASK_BWX) {
119 		patchfunc(alpha_copystr_bwx, alpha_copystr_bwx_end,
120 		    alpha_copystr, alpha_copystr_end);
121 	}
122 
123 #if defined(MULTIPROCESSOR)
124 	if (is_mp) {
125 		KASSERT(curcpu()->ci_flags & CPUF_PRIMARY);
126 		KASSERT((cpus_running & ~(1UL << cpu_number())) == 0);
127 
128 		patch_lock_stubs();
129 
130 		patchfunc(_membar_producer_mp, _membar_producer_mp_end,
131 			  _membar_producer, _membar_producer_end);
132 		patchfunc(_membar_sync_mp, _membar_sync_mp_end,
133 			  _membar_sync, _membar_sync_end);
134 	}
135 #else
136 	KASSERT(is_mp == false);
137 #endif /* MULTIPROCESSOR */
138 }
139