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 if (smccc_get_version() < SMCCC_MAKE_VERSION(1, 1))
74 return;
75
76 /* Check we have Errata 1.0 or later */
77 version = psci_call(EM_VERSION, 0, 0, 0);
78 if (version < EM_VERSION_MIN)
79 return;
80
81 if (BUS_ADD_CHILD(parent, 0, "errata", -1) == NULL)
82 device_printf(parent, "add errata child failed\n");
83 }
84
85 static int
errata_probe(device_t dev)86 errata_probe(device_t dev)
87 {
88 device_set_desc(dev, "Arm SMCCC Errata Management");
89 return (BUS_PROBE_NOWILDCARD);
90 }
91
92 static int
errata_attach(device_t dev)93 errata_attach(device_t dev)
94 {
95 /* Check for EM_CPU_ERRATUM_FEATURES. It's mandatory, so should exist */
96 if (arm_smccc_invoke(EM_FEATURES, EM_CPU_ERRATUM_FEATURES, NULL) < 0) {
97 device_printf(dev,
98 "EM_CPU_ERRATUM_FEATURES is not implemented\n");
99 return (ENXIO);
100 }
101
102 cpu_feat_register_errata_check(errata_cpu_feat_errata_check);
103
104 return (0);
105 }
106
107 static cpu_feat_errata
errata_cpu_feat_errata_check(const struct cpu_feat * feat __unused,u_int errata_id)108 errata_cpu_feat_errata_check(const struct cpu_feat *feat __unused, u_int errata_id)
109 {
110 struct arm_smccc_res res;
111
112 switch(arm_smccc_invoke(EM_CPU_ERRATUM_FEATURES, errata_id, 0, &res)) {
113 default:
114 return (ERRATA_UNKNOWN);
115 case ERRATA_NOT_AFFECTED:
116 return (ERRATA_NONE);
117 case ERRATA_AFFECTED:
118 return (ERRATA_AFFECTED);
119 case ERRATA_HIGHER_EL_MITIGATION:
120 return (ERRATA_FW_MITIGAION);
121 }
122 }
123
124 static device_method_t errata_methods[] = {
125 DEVMETHOD(device_identify, errata_identify),
126 DEVMETHOD(device_probe, errata_probe),
127 DEVMETHOD(device_attach, errata_attach),
128
129 DEVMETHOD_END
130 };
131
132 static driver_t errata_driver = {
133 "errata",
134 errata_methods,
135 0
136 };
137
138 DRIVER_MODULE(errata, smccc, errata_driver, 0, 0);
139