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
  37 #define ARM64_NCAPS                             11
  38
  39 #ifndef __ASSEMBLY__
  40
  41 #include <linux/kernel.h>
  42
  43 /* CPU feature register tracking */
  44 enum ftr_type {
  45         FTR_EXACT,      /* Use a predefined safe value */
  46         FTR_LOWER_SAFE, /* Smaller value is safe */
  47         FTR_HIGHER_SAFE,/* Bigger value is safe */
  48 };
  49
  50 #define FTR_STRICT      true    /* SANITY check strict matching required */
  51 #define FTR_NONSTRICT   false   /* SANITY check ignored */
  52
  53 #define FTR_SIGNED      true    /* Value should be treated as signed */
  54 #define FTR_UNSIGNED    false   /* Value should be treated as unsigned */
  55
  56 struct arm64_ftr_bits {
  57         bool            sign;   /* Value is signed ? */
  58         bool            strict; /* CPU Sanity check: strict matching required ? */
  59         enum ftr_type   type;
  60         u8              shift;
  61         u8              width;
  62         s64             safe_val; /* safe value for discrete features */
  63 };
  64
  65 /*
  66  * @arm64_ftr_reg - Feature register
  67  * @strict_mask         Bits which should match across all CPUs for sanity.
  68  * @sys_val             Safe value across the CPUs (system view)
  69  */
  70 struct arm64_ftr_reg {
  71         u32                     sys_id;
  72         const char              *name;
  73         u64                     strict_mask;
  74         u64                     sys_val;
  75         struct arm64_ftr_bits   *ftr_bits;
  76 };
  77
  78 struct arm64_cpu_capabilities {
  79         const char *desc;
  80         u16 capability;
  81         bool (*matches)(const struct arm64_cpu_capabilities *);
  82         void (*enable)(void *);         /* Called on all active CPUs */
  83         union {
  84                 struct {        /* To be used for erratum handling only */
  85                         u32 midr_model;
  86                         u32 midr_range_min, midr_range_max;
  87                 };
  88
  89                 struct {        /* Feature register checking */
  90                         u32 sys_reg;
  91                         int field_pos;
  92                         int min_field_value;
  93                         int hwcap_type;
  94                         unsigned long hwcap;
  95                 };
  96         };
  97 };
  98
  99 extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
 100
 101 static inline bool cpu_have_feature(unsigned int num)
 102 {
 103         return elf_hwcap & (1UL << num);
 104 }
 105
 106 static inline bool cpus_have_cap(unsigned int num)
 107 {
 108         if (num >= ARM64_NCAPS)
 109                 return false;
 110         return test_bit(num, cpu_hwcaps);
 111 }
 112
 113 static inline void cpus_set_cap(unsigned int num)
 114 {
 115         if (num >= ARM64_NCAPS)
 116                 pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
 117                         num, ARM64_NCAPS);
 118         else
 119                 __set_bit(num, cpu_hwcaps);
 120 }
 121
 122 static inline int __attribute_const__
 123 cpuid_feature_extract_field_width(u64 features, int field, int width)
 124 {
 125         return (s64)(features << (64 - width - field)) >> (64 - width);
 126 }
 127
 128 static inline int __attribute_const__
 129 cpuid_feature_extract_field(u64 features, int field)
 130 {
 131         return cpuid_feature_extract_field_width(features, field, 4);
 132 }
 133
 134 static inline unsigned int __attribute_const__
 135 cpuid_feature_extract_unsigned_field_width(u64 features, int field, int width)
 136 {
 137         return (u64)(features << (64 - width - field)) >> (64 - width);
 138 }
 139
 140 static inline unsigned int __attribute_const__
 141 cpuid_feature_extract_unsigned_field(u64 features, int field)
 142 {
 143         return cpuid_feature_extract_unsigned_field_width(features, field, 4);
 144 }
 145
 146 static inline u64 arm64_ftr_mask(struct arm64_ftr_bits *ftrp)
 147 {
 148         return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);
 149 }
 150
 151 static inline s64 arm64_ftr_value(struct arm64_ftr_bits *ftrp, u64 val)
 152 {
 153         return ftrp->sign ?
 154                 cpuid_feature_extract_field_width(val, ftrp->shift, ftrp->width) :
 155                 cpuid_feature_extract_unsigned_field_width(val, ftrp->shift, ftrp->width);
 156 }
 157
 158 static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0)
 159 {
 160         return cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL_SHIFT) == 0x1 ||
 161                 cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL0_SHIFT) == 0x1;
 162 }
 163
 164 void __init setup_cpu_features(void);
 165
 166 void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
 167                             const char *info);
 168 void check_local_cpu_errata(void);
 169
 170 #ifdef CONFIG_HOTPLUG_CPU
 171 void verify_local_cpu_capabilities(void);
 172 #else
 173 static inline void verify_local_cpu_capabilities(void)
 174 {
 175 }
 176 #endif
 177
 178 u64 read_system_reg(u32 id);
 179
 180 static inline bool cpu_supports_mixed_endian_el0(void)
 181 {
 182         return id_aa64mmfr0_mixed_endian_el0(read_cpuid(SYS_ID_AA64MMFR0_EL1));
 183 }
 184
 185 static inline bool system_supports_mixed_endian_el0(void)
 186 {
 187         return id_aa64mmfr0_mixed_endian_el0(read_system_reg(SYS_ID_AA64MMFR0_EL1));
 188 }
 189
 190 #endif /* __ASSEMBLY__ */
 191
 192 #endif