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/hwcap.h> 13 #include <asm/sysreg.h> 14 15 /* 16 * In the arm64 world (as in the ARM world), elf_hwcap is used both internally 17 * in the kernel and for user space to keep track of which optional features 18 * are supported by the current system. So let's map feature 'x' to HWCAP_x. 19 * Note that HWCAP_x constants are bit fields so we need to take the log. 20 */ 21 22 #define MAX_CPU_FEATURES (8 * sizeof(elf_hwcap)) 23 #define cpu_feature(x) ilog2(HWCAP_ ## x) 24 25 #define ARM64_WORKAROUND_CLEAN_CACHE 0 26 #define ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE 1 27 #define ARM64_WORKAROUND_845719 2 28 #define ARM64_HAS_SYSREG_GIC_CPUIF 3 29 #define ARM64_HAS_PAN 4 30 #define ARM64_HAS_LSE_ATOMICS 5 31 #define ARM64_WORKAROUND_CAVIUM_23154 6 32 #define ARM64_WORKAROUND_834220 7 33 34 #define ARM64_NCAPS 8 35 36 #ifndef __ASSEMBLY__ 37 38 #include <linux/kernel.h> 39 40 /* CPU feature register tracking */ 41 enum ftr_type { 42 FTR_EXACT, /* Use a predefined safe value */ 43 FTR_LOWER_SAFE, /* Smaller value is safe */ 44 FTR_HIGHER_SAFE,/* Bigger value is safe */ 45 }; 46 47 #define FTR_STRICT true /* SANITY check strict matching required */ 48 #define FTR_NONSTRICT false /* SANITY check ignored */ 49 50 struct arm64_ftr_bits { 51 bool strict; /* CPU Sanity check: strict matching required ? */ 52 enum ftr_type type; 53 u8 shift; 54 u8 width; 55 s64 safe_val; /* safe value for discrete features */ 56 }; 57 58 /* 59 * @arm64_ftr_reg - Feature register 60 * @strict_mask Bits which should match across all CPUs for sanity. 61 * @sys_val Safe value across the CPUs (system view) 62 */ 63 struct arm64_ftr_reg { 64 u32 sys_id; 65 const char *name; 66 u64 strict_mask; 67 u64 sys_val; 68 struct arm64_ftr_bits *ftr_bits; 69 }; 70 71 struct arm64_cpu_capabilities { 72 const char *desc; 73 u16 capability; 74 bool (*matches)(const struct arm64_cpu_capabilities *); 75 void (*enable)(void *); /* Called on all active CPUs */ 76 union { 77 struct { /* To be used for erratum handling only */ 78 u32 midr_model; 79 u32 midr_range_min, midr_range_max; 80 }; 81 82 struct { /* Feature register checking */ 83 u32 sys_reg; 84 int field_pos; 85 int min_field_value; 86 int hwcap_type; 87 unsigned long hwcap; 88 }; 89 }; 90 }; 91 92 extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS); 93 94 static inline bool cpu_have_feature(unsigned int num) 95 { 96 return elf_hwcap & (1UL << num); 97 } 98 99 static inline bool cpus_have_cap(unsigned int num) 100 { 101 if (num >= ARM64_NCAPS) 102 return false; 103 return test_bit(num, cpu_hwcaps); 104 } 105 106 static inline void cpus_set_cap(unsigned int num) 107 { 108 if (num >= ARM64_NCAPS) 109 pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n", 110 num, ARM64_NCAPS); 111 else 112 __set_bit(num, cpu_hwcaps); 113 } 114 115 static inline int __attribute_const__ 116 cpuid_feature_extract_field_width(u64 features, int field, int width) 117 { 118 return (s64)(features << (64 - width - field)) >> (64 - width); 119 } 120 121 static inline int __attribute_const__ 122 cpuid_feature_extract_field(u64 features, int field) 123 { 124 return cpuid_feature_extract_field_width(features, field, 4); 125 } 126 127 static inline u64 arm64_ftr_mask(struct arm64_ftr_bits *ftrp) 128 { 129 return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift); 130 } 131 132 static inline s64 arm64_ftr_value(struct arm64_ftr_bits *ftrp, u64 val) 133 { 134 return cpuid_feature_extract_field_width(val, ftrp->shift, ftrp->width); 135 } 136 137 static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0) 138 { 139 return cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL_SHIFT) == 0x1 || 140 cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL0_SHIFT) == 0x1; 141 } 142 143 void __init setup_cpu_features(void); 144 145 void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps, 146 const char *info); 147 void check_local_cpu_errata(void); 148 149 #ifdef CONFIG_HOTPLUG_CPU 150 void verify_local_cpu_capabilities(void); 151 #else 152 static inline void verify_local_cpu_capabilities(void) 153 { 154 } 155 #endif 156 157 u64 read_system_reg(u32 id); 158 159 static inline bool cpu_supports_mixed_endian_el0(void) 160 { 161 return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1)); 162 } 163 164 static inline bool system_supports_mixed_endian_el0(void) 165 { 166 return id_aa64mmfr0_mixed_endian_el0(read_system_reg(SYS_ID_AA64MMFR0_EL1)); 167 } 168 169 #endif /* __ASSEMBLY__ */ 170 171 #endif 172