1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2024 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
28 #include <sys/param.h>
29 #include <sys/systm.h>
30 #include <sys/kernel.h>
31
32 #include <machine/cpu.h>
33 #include <machine/cpu_feat.h>
34
35 /* TODO: Make this a list if we ever grow a callback other than smccc_errata */
36 static cpu_feat_errata_check_fn cpu_feat_check_cb = NULL;
37
38 void
enable_cpu_feat(uint32_t stage)39 enable_cpu_feat(uint32_t stage)
40 {
41 struct cpu_feat **featp, *feat;
42 uint32_t midr;
43 u_int errata_count, *errata_list;
44 cpu_feat_errata errata_status;
45
46 MPASS((stage & ~CPU_FEAT_STAGE_MASK) == 0);
47
48 midr = get_midr();
49 SET_FOREACH(featp, cpu_feat_set) {
50 feat = *featp;
51
52 /* Run the enablement code at the correct stage of boot */
53 if ((feat->feat_flags & CPU_FEAT_STAGE_MASK) != stage)
54 continue;
55
56 /* If the feature is system wide run on a single CPU */
57 if ((feat->feat_flags & CPU_FEAT_SCOPE_MASK)==CPU_FEAT_SYSTEM &&
58 PCPU_GET(cpuid) != 0)
59 continue;
60
61 if (feat->feat_check != NULL && !feat->feat_check(feat, midr))
62 continue;
63
64 /*
65 * Check if the feature has any errata that may need a
66 * workaround applied (or it is to install the workaround for
67 * known errata.
68 */
69 errata_status = ERRATA_NONE;
70 errata_list = NULL;
71 errata_count = 0;
72 if (feat->feat_has_errata != NULL) {
73 if (feat->feat_has_errata(feat, midr, &errata_list,
74 &errata_count)) {
75 /* Assume we are affected */
76 errata_status = ERRATA_AFFECTED;
77 }
78 }
79
80 if (errata_status == ERRATA_AFFECTED &&
81 cpu_feat_check_cb != NULL) {
82 for (int i = 0; i < errata_count; i++) {
83 cpu_feat_errata new_status;
84
85 /* Check if affected by this erratum */
86 new_status = cpu_feat_check_cb(feat,
87 errata_list[i]);
88 if (new_status != ERRATA_UNKNOWN) {
89 errata_status = new_status;
90 errata_list = &errata_list[i];
91 errata_count = 1;
92 break;
93 }
94 }
95 }
96
97 /* Shouldn't be possible */
98 MPASS(errata_status != ERRATA_UNKNOWN);
99
100 feat->feat_enable(feat, errata_status, errata_list,
101 errata_count);
102 }
103 }
104
105 static void
enable_cpu_feat_after_dev(void * dummy __unused)106 enable_cpu_feat_after_dev(void *dummy __unused)
107 {
108 MPASS(PCPU_GET(cpuid) == 0);
109 enable_cpu_feat(CPU_FEAT_AFTER_DEV);
110 }
111 SYSINIT(enable_cpu_feat_after_dev, SI_SUB_CONFIGURE, SI_ORDER_MIDDLE,
112 enable_cpu_feat_after_dev, NULL);
113
114 void
cpu_feat_register_errata_check(cpu_feat_errata_check_fn cb)115 cpu_feat_register_errata_check(cpu_feat_errata_check_fn cb)
116 {
117 MPASS(cpu_feat_check_cb == NULL);
118 cpu_feat_check_cb = cb;
119 }
120