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