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/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 #define ARM64_HAS_NO_HW_PREFETCH                8
  34 #define ARM64_HAS_UAO                           9
  35 #define ARM64_ALT_PAN_NOT_UAO                   10
  36 #define ARM64_HAS_VIRT_HOST_EXTN                11
  37 #define ARM64_WORKAROUND_CAVIUM_27456           12
  38 #define ARM64_HAS_32BIT_EL0                     13
  39 #define ARM64_HYP_OFFSET_LOW                    14
  40 #define ARM64_MISMATCHED_CACHE_LINE_SIZE        15
  41
  42 #define ARM64_NCAPS                             16
  43
  44 #ifndef __ASSEMBLY__
  45
  46 #include <linux/bug.h>
  47 #include <linux/jump_label.h>
  48 #include <linux/kernel.h>
  49
  50 /* CPU feature register tracking */
  51 enum ftr_type {
  52         FTR_EXACT,      /* Use a predefined safe value */
  53         FTR_LOWER_SAFE, /* Smaller value is safe */
  54         FTR_HIGHER_SAFE,/* Bigger value is safe */
  55 };
  56
  57 #define FTR_STRICT      true    /* SANITY check strict matching required */
  58 #define FTR_NONSTRICT   false   /* SANITY check ignored */
  59
  60 #define FTR_SIGNED      true    /* Value should be treated as signed */
  61 #define FTR_UNSIGNED    false   /* Value should be treated as unsigned */
  62
  63 struct arm64_ftr_bits {
  64         bool            sign;   /* Value is signed ? */
  65         bool            strict; /* CPU Sanity check: strict matching required ? */
  66         enum ftr_type   type;
  67         u8              shift;
  68         u8              width;
  69         s64             safe_val; /* safe value for FTR_EXACT features */
  70 };
  71
  72 /*
  73  * @arm64_ftr_reg - Feature register
  74  * @strict_mask         Bits which should match across all CPUs for sanity.
  75  * @sys_val             Safe value across the CPUs (system view)
  76  */
  77 struct arm64_ftr_reg {
  78         const char                      *name;
  79         u64                             strict_mask;
  80         u64                             sys_val;
  81         const struct arm64_ftr_bits     *ftr_bits;
  82 };
  83
  84 extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0;
  85
  86 /* scope of capability check */
  87 enum {
  88         SCOPE_SYSTEM,
  89         SCOPE_LOCAL_CPU,
  90 };
  91
  92 struct arm64_cpu_capabilities {
  93         const char *desc;
  94         u16 capability;
  95         int def_scope;                  /* default scope */
  96         bool (*matches)(const struct arm64_cpu_capabilities *caps, int scope);
  97         int (*enable)(void *);          /* Called on all active CPUs */
  98         union {
  99                 struct {        /* To be used for erratum handling only */
 100                         u32 midr_model;
 101                         u32 midr_range_min, midr_range_max;
 102                 };
 103
 104                 struct {        /* Feature register checking */
 105                         u32 sys_reg;
 106                         u8 field_pos;
 107                         u8 min_field_value;
 108                         u8 hwcap_type;
 109                         bool sign;
 110                         unsigned long hwcap;
 111                 };
 112         };
 113 };
 114
 115 extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
 116 extern struct static_key_false cpu_hwcap_keys[ARM64_NCAPS];
 117
 118 bool this_cpu_has_cap(unsigned int cap);
 119
 120 static inline bool cpu_have_feature(unsigned int num)
 121 {
 122         return elf_hwcap & (1UL << num);
 123 }
 124
 125 /* System capability check for constant caps */
 126 static inline bool cpus_have_const_cap(int num)
 127 {
 128         if (num >= ARM64_NCAPS)
 129                 return false;
 130         return static_branch_unlikely(&cpu_hwcap_keys[num]);
 131 }
 132
 133 static inline bool cpus_have_cap(unsigned int num)
 134 {
 135         if (num >= ARM64_NCAPS)
 136                 return false;
 137         return test_bit(num, cpu_hwcaps);
 138 }
 139
 140 static inline void cpus_set_cap(unsigned int num)
 141 {
 142         if (num >= ARM64_NCAPS) {
 143                 pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
 144                         num, ARM64_NCAPS);
 145         } else {
 146                 __set_bit(num, cpu_hwcaps);
 147                 static_branch_enable(&cpu_hwcap_keys[num]);
 148         }
 149 }
 150
 151 static inline int __attribute_const__
 152 cpuid_feature_extract_signed_field_width(u64 features, int field, int width)
 153 {
 154         return (s64)(features << (64 - width - field)) >> (64 - width);
 155 }
 156
 157 static inline int __attribute_const__
 158 cpuid_feature_extract_signed_field(u64 features, int field)
 159 {
 160         return cpuid_feature_extract_signed_field_width(features, field, 4);
 161 }
 162
 163 static inline unsigned int __attribute_const__
 164 cpuid_feature_extract_unsigned_field_width(u64 features, int field, int width)
 165 {
 166         return (u64)(features << (64 - width - field)) >> (64 - width);
 167 }
 168
 169 static inline unsigned int __attribute_const__
 170 cpuid_feature_extract_unsigned_field(u64 features, int field)
 171 {
 172         return cpuid_feature_extract_unsigned_field_width(features, field, 4);
 173 }
 174
 175 static inline u64 arm64_ftr_mask(const struct arm64_ftr_bits *ftrp)
 176 {
 177         return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);
 178 }
 179
 180 static inline int __attribute_const__
 181 cpuid_feature_extract_field(u64 features, int field, bool sign)
 182 {
 183         return (sign) ?
 184                 cpuid_feature_extract_signed_field(features, field) :
 185                 cpuid_feature_extract_unsigned_field(features, field);
 186 }
 187
 188 static inline s64 arm64_ftr_value(const struct arm64_ftr_bits *ftrp, u64 val)
 189 {
 190         return (s64)cpuid_feature_extract_field(val, ftrp->shift, ftrp->sign);
 191 }
 192
 193 static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0)
 194 {
 195         return cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_BIGENDEL_SHIFT) == 0x1 ||
 196                 cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_BIGENDEL0_SHIFT) == 0x1;
 197 }
 198
 199 static inline bool id_aa64pfr0_32bit_el0(u64 pfr0)
 200 {
 201         u32 val = cpuid_feature_extract_unsigned_field(pfr0, ID_AA64PFR0_EL0_SHIFT);
 202
 203         return val == ID_AA64PFR0_EL0_32BIT_64BIT;
 204 }
 205
 206 void __init setup_cpu_features(void);
 207
 208 void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
 209                             const char *info);
 210 void enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps);
 211 void check_local_cpu_capabilities(void);
 212
 213 void update_cpu_errata_workarounds(void);
 214 void __init enable_errata_workarounds(void);
 215 void verify_local_cpu_errata_workarounds(void);
 216
 217 u64 read_system_reg(u32 id);
 218
 219 static inline bool cpu_supports_mixed_endian_el0(void)
 220 {
 221         return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1));
 222 }
 223
 224 static inline bool system_supports_32bit_el0(void)
 225 {
 226         return cpus_have_const_cap(ARM64_HAS_32BIT_EL0);
 227 }
 228
 229 static inline bool system_supports_mixed_endian_el0(void)
 230 {
 231         return id_aa64mmfr0_mixed_endian_el0(read_system_reg(SYS_ID_AA64MMFR0_EL1));
 232 }
 233
 234 #endif /* __ASSEMBLY__ */
 235
 236 #endif