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 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 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 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 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