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 #ifndef _MACHINE_CPU_FEAT_H_ 29 #define _MACHINE_CPU_FEAT_H_ 30 31 #include <sys/linker_set.h> 32 #include <sys/sysctl.h> 33 34 typedef enum { 35 ERRATA_UNKNOWN, /* Unknown erratum */ 36 ERRATA_NONE, /* No errata for this feature on this system. */ 37 ERRATA_AFFECTED, /* There is errata on this system. */ 38 ERRATA_FW_MITIGAION, /* There is errata, and a firmware */ 39 /* mitigation. The mitigation may need a */ 40 /* kernel component. */ 41 } cpu_feat_errata; 42 43 typedef enum { 44 /* 45 * Don't implement the feature or erratum wrokarount, 46 * e.g. the feature is not implemented or erratum is 47 * for another CPU. 48 */ 49 FEAT_ALWAYS_DISABLE, 50 51 /* 52 * Disable by default, but allow the user to enable, 53 * e.g. For a rare erratum with a workaround, Arm 54 * Category B (rare) or similar. 55 */ 56 FEAT_DEFAULT_DISABLE, 57 58 /* 59 * Enabled by default, bit allow the user to disable, 60 * e.g. For a common erratum with a workaround, Arm 61 * Category A or B or similar. 62 */ 63 FEAT_DEFAULT_ENABLE, 64 65 /* 66 * Always enabled. Used when there is no way for the kernel to 67 * work without the feature, e.g. configuring the interrupt 68 * controller. 69 */ 70 FEAT_ALWAYS_ENABLE, 71 } cpu_feat_en; 72 73 #define CPU_FEAT_STAGE_MASK 0x00000001 74 #define CPU_FEAT_EARLY_BOOT 0x00000000 75 #define CPU_FEAT_AFTER_DEV 0x00000001 76 77 #define CPU_FEAT_SCOPE_MASK 0x00000010 78 #define CPU_FEAT_PER_CPU 0x00000000 79 #define CPU_FEAT_SYSTEM 0x00000010 80 81 #define CPU_FEAT_USER_ENABLED 0x40000000 82 #define CPU_FEAT_USER_DISABLED 0x80000000 83 84 struct cpu_feat; 85 86 typedef cpu_feat_en (cpu_feat_check)(const struct cpu_feat *, u_int); 87 typedef bool (cpu_feat_has_errata)(const struct cpu_feat *, u_int, 88 u_int **, u_int *); 89 typedef bool (cpu_feat_enable)(const struct cpu_feat *, cpu_feat_errata, 90 u_int *, u_int); 91 typedef void (cpu_feat_disabled)(const struct cpu_feat *); 92 93 struct cpu_feat { 94 const char *feat_name; 95 cpu_feat_check *feat_check; 96 cpu_feat_has_errata *feat_has_errata; 97 cpu_feat_enable *feat_enable; 98 cpu_feat_disabled *feat_disabled; 99 uint32_t feat_flags; 100 bool feat_enabled; 101 }; 102 SET_DECLARE(cpu_feat_set, struct cpu_feat); 103 104 SYSCTL_DECL(_hw_feat); 105 106 #define CPU_FEAT(name, descr, check, has_errata, enable, disabled, flags) \ 107 static struct cpu_feat name = { \ 108 .feat_name = #name, \ 109 .feat_check = check, \ 110 .feat_has_errata = has_errata, \ 111 .feat_enable = enable, \ 112 .feat_disabled = disabled, \ 113 .feat_flags = flags, \ 114 .feat_enabled = false, \ 115 }; \ 116 DATA_SET(cpu_feat_set, name); \ 117 SYSCTL_BOOL(_hw_feat, OID_AUTO, name, CTLFLAG_RD, &name.feat_enabled, \ 118 0, descr) 119 120 /* 121 * Allow drivers to mark an erratum as worked around, e.g. the Errata 122 * Management ABI may know the workaround isn't needed on a given system. 123 */ 124 typedef cpu_feat_errata (*cpu_feat_errata_check_fn)(const struct cpu_feat *, 125 u_int); 126 void cpu_feat_register_errata_check(cpu_feat_errata_check_fn); 127 128 void enable_cpu_feat(uint32_t); 129 130 /* Check if an erratum is in the list of errata */ 131 static inline bool 132 cpu_feat_has_erratum(u_int *errata_list, u_int errata_count, u_int erratum) 133 { 134 for (u_int i = 0; i < errata_count; i++) 135 if (errata_list[0] == erratum) 136 return (true); 137 138 return (false); 139 } 140 141 #endif /* _MACHINE_CPU_FEAT_H_ */ 142