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 /*
29 * A driver for the Arm Errata Management Firmware Interface (Errata ABI).
30 * This queries into the SMCCC firmware for the status of errata using the
31 * interface documented in den0100 [1].
32 *
33 * [1] https://developer.arm.com/documentation/den0100/latest
34 */
35
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/bus.h>
39 #include <sys/eventhandler.h>
40 #include <sys/kernel.h>
41 #include <sys/malloc.h>
42 #include <sys/module.h>
43 #include <sys/random.h>
44
45 #include <dev/psci/psci.h>
46 #include <dev/psci/smccc.h>
47
48 #include <machine/cpu_feat.h>
49
50 #define ERRATA_HIGHER_EL_MITIGATION 3
51 #define ERRATA_NOT_AFFECTED 2
52 #define ERRATA_AFFECTED 1
53
54 #define EM_VERSION SMCCC_FUNC_ID(SMCCC_FAST_CALL, \
55 SMCCC_32BIT_CALL, SMCCC_STD_SECURE_SERVICE_CALLS, 0xf0u)
56 #define EM_VERSION_MIN 0x10000L
57 #define EM_FEATURES SMCCC_FUNC_ID(SMCCC_FAST_CALL, \
58 SMCCC_32BIT_CALL, SMCCC_STD_SECURE_SERVICE_CALLS, 0xf1u)
59 #define EM_CPU_ERRATUM_FEATURES SMCCC_FUNC_ID(SMCCC_FAST_CALL, \
60 SMCCC_32BIT_CALL, SMCCC_STD_SECURE_SERVICE_CALLS, 0xf2u)
61
62 static device_identify_t errata_identify;
63 static device_probe_t errata_probe;
64 static device_attach_t errata_attach;
65 static cpu_feat_errata errata_cpu_feat_errata_check(const struct cpu_feat *,
66 u_int);
67
68 static void
errata_identify(driver_t * driver,device_t parent)69 errata_identify(driver_t *driver, device_t parent)
70 {
71 int32_t version;
72
73 /* Check if Errata ABI is supported */
74 if (smccc_arch_features(EM_VERSION) != SMCCC_RET_SUCCESS)
75 return;
76
77 /* Check we have Errata 1.0 or later */
78 version = psci_call(EM_VERSION, 0, 0, 0);
79 if (version < EM_VERSION_MIN)
80 return;
81
82 if (BUS_ADD_CHILD(parent, 0, "errata", DEVICE_UNIT_ANY) == NULL)
83 device_printf(parent, "add errata child failed\n");
84 }
85
86 static int
errata_probe(device_t dev)87 errata_probe(device_t dev)
88 {
89 device_set_desc(dev, "Arm SMCCC Errata Management");
90 return (BUS_PROBE_NOWILDCARD);
91 }
92
93 static int
errata_attach(device_t dev)94 errata_attach(device_t dev)
95 {
96 /* Check for EM_CPU_ERRATUM_FEATURES. It's mandatory, so should exist */
97 if (arm_smccc_invoke(EM_FEATURES, EM_CPU_ERRATUM_FEATURES, NULL) < 0) {
98 device_printf(dev,
99 "EM_CPU_ERRATUM_FEATURES is not implemented\n");
100 return (ENXIO);
101 }
102
103 cpu_feat_register_errata_check(errata_cpu_feat_errata_check);
104
105 return (0);
106 }
107
108 static cpu_feat_errata
errata_cpu_feat_errata_check(const struct cpu_feat * feat __unused,u_int errata_id)109 errata_cpu_feat_errata_check(const struct cpu_feat *feat __unused, u_int errata_id)
110 {
111 struct arm_smccc_res res;
112
113 switch(arm_smccc_invoke(EM_CPU_ERRATUM_FEATURES, errata_id, 0, &res)) {
114 default:
115 return (ERRATA_UNKNOWN);
116 case ERRATA_NOT_AFFECTED:
117 return (ERRATA_NONE);
118 case ERRATA_AFFECTED:
119 return (ERRATA_AFFECTED);
120 case ERRATA_HIGHER_EL_MITIGATION:
121 return (ERRATA_FW_MITIGAION);
122 }
123 }
124
125 static device_method_t errata_methods[] = {
126 DEVMETHOD(device_identify, errata_identify),
127 DEVMETHOD(device_probe, errata_probe),
128 DEVMETHOD(device_attach, errata_attach),
129
130 DEVMETHOD_END
131 };
132
133 static driver_t errata_driver = {
134 "errata",
135 errata_methods,
136 0
137 };
138
139 DRIVER_MODULE(errata, smccc, errata_driver, 0, 0);
140