arch/arm64/include/asm/cpufeature.h

   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_system_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_system_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