1 /* 2 * Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8 9 #ifndef __ASM_CPUFEATURE_H 10 #define __ASM_CPUFEATURE_H 11 12 #include <asm/cpucaps.h> 13 #include <asm/hwcap.h> 14 #include <asm/sysreg.h> 15 16 /* 17 * In the arm64 world (as in the ARM world), elf_hwcap is used both internally 18 * in the kernel and for user space to keep track of which optional features 19 * are supported by the current system. So let's map feature 'x' to HWCAP_x. 20 * Note that HWCAP_x constants are bit fields so we need to take the log. 21 */ 22 23 #define MAX_CPU_FEATURES (8 * sizeof(elf_hwcap)) 24 #define cpu_feature(x) ilog2(HWCAP_ ## x) 25 26 #ifndef __ASSEMBLY__ 27 28 #include <linux/bug.h> 29 #include <linux/jump_label.h> 30 #include <linux/kernel.h> 31 32 /* 33 * CPU feature register tracking 34 * 35 * The safe value of a CPUID feature field is dependent on the implications 36 * of the values assigned to it by the architecture. Based on the relationship 37 * between the values, the features are classified into 3 types - LOWER_SAFE, 38 * HIGHER_SAFE and EXACT. 39 * 40 * The lowest value of all the CPUs is chosen for LOWER_SAFE and highest 41 * for HIGHER_SAFE. It is expected that all CPUs have the same value for 42 * a field when EXACT is specified, failing which, the safe value specified 43 * in the table is chosen. 44 */ 45 46 enum ftr_type { 47 FTR_EXACT, /* Use a predefined safe value */ 48 FTR_LOWER_SAFE, /* Smaller value is safe */ 49 FTR_HIGHER_SAFE,/* Bigger value is safe */ 50 }; 51 52 #define FTR_STRICT true /* SANITY check strict matching required */ 53 #define FTR_NONSTRICT false /* SANITY check ignored */ 54 55 #define FTR_SIGNED true /* Value should be treated as signed */ 56 #define FTR_UNSIGNED false /* Value should be treated as unsigned */ 57 58 #define FTR_VISIBLE true /* Feature visible to the user space */ 59 #define FTR_HIDDEN false /* Feature is hidden from the user */ 60 61 struct arm64_ftr_bits { 62 bool sign; /* Value is signed ? */ 63 bool visible; 64 bool strict; /* CPU Sanity check: strict matching required ? */ 65 enum ftr_type type; 66 u8 shift; 67 u8 width; 68 s64 safe_val; /* safe value for FTR_EXACT features */ 69 }; 70 71 /* 72 * @arm64_ftr_reg - Feature register 73 * @strict_mask Bits which should match across all CPUs for sanity. 74 * @sys_val Safe value across the CPUs (system view) 75 */ 76 struct arm64_ftr_reg { 77 const char *name; 78 u64 strict_mask; 79 u64 user_mask; 80 u64 sys_val; 81 u64 user_val; 82 const struct arm64_ftr_bits *ftr_bits; 83 }; 84 85 extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0; 86 87 /* scope of capability check */ 88 enum { 89 SCOPE_SYSTEM, 90 SCOPE_LOCAL_CPU, 91 }; 92 93 struct arm64_cpu_capabilities { 94 const char *desc; 95 u16 capability; 96 int def_scope; /* default scope */ 97 bool (*matches)(const struct arm64_cpu_capabilities *caps, int scope); 98 int (*enable)(void *); /* Called on all active CPUs */ 99 union { 100 struct { /* To be used for erratum handling only */ 101 u32 midr_model; 102 u32 midr_range_min, midr_range_max; 103 }; 104 105 struct { /* Feature register checking */ 106 u32 sys_reg; 107 u8 field_pos; 108 u8 min_field_value; 109 u8 hwcap_type; 110 bool sign; 111 unsigned long hwcap; 112 }; 113 }; 114 }; 115 116 extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS); 117 extern struct static_key_false cpu_hwcap_keys[ARM64_NCAPS]; 118 119 bool this_cpu_has_cap(unsigned int cap); 120 121 static inline bool cpu_have_feature(unsigned int num) 122 { 123 return elf_hwcap & (1UL << num); 124 } 125 126 /* System capability check for constant caps */ 127 static inline bool cpus_have_const_cap(int num) 128 { 129 if (num >= ARM64_NCAPS) 130 return false; 131 return static_branch_unlikely(&cpu_hwcap_keys[num]); 132 } 133 134 static inline bool cpus_have_cap(unsigned int num) 135 { 136 if (num >= ARM64_NCAPS) 137 return false; 138 return test_bit(num, cpu_hwcaps); 139 } 140 141 static inline void cpus_set_cap(unsigned int num) 142 { 143 if (num >= ARM64_NCAPS) { 144 pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n", 145 num, ARM64_NCAPS); 146 } else { 147 __set_bit(num, cpu_hwcaps); 148 static_branch_enable(&cpu_hwcap_keys[num]); 149 } 150 } 151 152 static inline int __attribute_const__ 153 cpuid_feature_extract_signed_field_width(u64 features, int field, int width) 154 { 155 return (s64)(features << (64 - width - field)) >> (64 - width); 156 } 157 158 static inline int __attribute_const__ 159 cpuid_feature_extract_signed_field(u64 features, int field) 160 { 161 return cpuid_feature_extract_signed_field_width(features, field, 4); 162 } 163 164 static inline unsigned int __attribute_const__ 165 cpuid_feature_extract_unsigned_field_width(u64 features, int field, int width) 166 { 167 return (u64)(features << (64 - width - field)) >> (64 - width); 168 } 169 170 static inline unsigned int __attribute_const__ 171 cpuid_feature_extract_unsigned_field(u64 features, int field) 172 { 173 return cpuid_feature_extract_unsigned_field_width(features, field, 4); 174 } 175 176 static inline u64 arm64_ftr_mask(const struct arm64_ftr_bits *ftrp) 177 { 178 return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift); 179 } 180 181 static inline u64 arm64_ftr_reg_user_value(const struct arm64_ftr_reg *reg) 182 { 183 return (reg->user_val | (reg->sys_val & reg->user_mask)); 184 } 185 186 static inline int __attribute_const__ 187 cpuid_feature_extract_field_width(u64 features, int field, int width, bool sign) 188 { 189 return (sign) ? 190 cpuid_feature_extract_signed_field_width(features, field, width) : 191 cpuid_feature_extract_unsigned_field_width(features, field, width); 192 } 193 194 static inline int __attribute_const__ 195 cpuid_feature_extract_field(u64 features, int field, bool sign) 196 { 197 return cpuid_feature_extract_field_width(features, field, 4, sign); 198 } 199 200 static inline s64 arm64_ftr_value(const struct arm64_ftr_bits *ftrp, u64 val) 201 { 202 return (s64)cpuid_feature_extract_field_width(val, ftrp->shift, ftrp->width, ftrp->sign); 203 } 204 205 static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0) 206 { 207 return cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_BIGENDEL_SHIFT) == 0x1 || 208 cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_BIGENDEL0_SHIFT) == 0x1; 209 } 210 211 static inline bool id_aa64pfr0_32bit_el0(u64 pfr0) 212 { 213 u32 val = cpuid_feature_extract_unsigned_field(pfr0, ID_AA64PFR0_EL0_SHIFT); 214 215 return val == ID_AA64PFR0_EL0_32BIT_64BIT; 216 } 217 218 void __init setup_cpu_features(void); 219 220 void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps, 221 const char *info); 222 void enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps); 223 void check_local_cpu_capabilities(void); 224 225 void update_cpu_errata_workarounds(void); 226 void __init enable_errata_workarounds(void); 227 void verify_local_cpu_errata_workarounds(void); 228 229 u64 read_sanitised_ftr_reg(u32 id); 230 231 static inline bool cpu_supports_mixed_endian_el0(void) 232 { 233 return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1)); 234 } 235 236 static inline bool system_supports_32bit_el0(void) 237 { 238 return cpus_have_const_cap(ARM64_HAS_32BIT_EL0); 239 } 240 241 static inline bool system_supports_mixed_endian_el0(void) 242 { 243 return id_aa64mmfr0_mixed_endian_el0(read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1)); 244 } 245 246 static inline bool system_supports_fpsimd(void) 247 { 248 return !cpus_have_const_cap(ARM64_HAS_NO_FPSIMD); 249 } 250 251 static inline bool system_uses_ttbr0_pan(void) 252 { 253 return IS_ENABLED(CONFIG_ARM64_SW_TTBR0_PAN) && 254 !cpus_have_const_cap(ARM64_HAS_PAN); 255 } 256 257 #endif /* __ASSEMBLY__ */ 258 259 #endif 260