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
  38 #define ARM64_NCAPS                             12
  39
  40 #ifndef __ASSEMBLY__
  41
  42 #include <linux/kernel.h>
  43
  44 /* CPU feature register tracking */
  45 enum ftr_type {
  46         FTR_EXACT,      /* Use a predefined safe value */
  47         FTR_LOWER_SAFE, /* Smaller value is safe */
  48         FTR_HIGHER_SAFE,/* Bigger value is safe */
  49 };
  50
  51 #define FTR_STRICT      true    /* SANITY check strict matching required */
  52 #define FTR_NONSTRICT   false   /* SANITY check ignored */
  53
  54 #define FTR_SIGNED      true    /* Value should be treated as signed */
  55 #define FTR_UNSIGNED    false   /* Value should be treated as unsigned */
  56
  57 struct arm64_ftr_bits {
  58         bool            sign;   /* Value is signed ? */
  59         bool            strict; /* CPU Sanity check: strict matching required ? */
  60         enum ftr_type   type;
  61         u8              shift;
  62         u8              width;
  63         s64             safe_val; /* safe value for discrete features */
  64 };
  65
  66 /*
  67  * @arm64_ftr_reg - Feature register
  68  * @strict_mask         Bits which should match across all CPUs for sanity.
  69  * @sys_val             Safe value across the CPUs (system view)
  70  */
  71 struct arm64_ftr_reg {
  72         u32                     sys_id;
  73         const char              *name;
  74         u64                     strict_mask;
  75         u64                     sys_val;
  76         struct arm64_ftr_bits   *ftr_bits;
  77 };
  78
  79 struct arm64_cpu_capabilities {
  80         const char *desc;
  81         u16 capability;
  82         bool (*matches)(const struct arm64_cpu_capabilities *);
  83         void (*enable)(void *);         /* Called on all active CPUs */
  84         union {
  85                 struct {        /* To be used for erratum handling only */
  86                         u32 midr_model;
  87                         u32 midr_range_min, midr_range_max;
  88                 };
  89
  90                 struct {        /* Feature register checking */
  91                         u32 sys_reg;
  92                         int field_pos;
  93                         int min_field_value;
  94                         int hwcap_type;
  95                         unsigned long hwcap;
  96                 };
  97         };
  98 };
  99
 100 extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
 101
 102 static inline bool cpu_have_feature(unsigned int num)
 103 {
 104         return elf_hwcap & (1UL << num);
 105 }
 106
 107 static inline bool cpus_have_cap(unsigned int num)
 108 {
 109         if (num >= ARM64_NCAPS)
 110                 return false;
 111         return test_bit(num, cpu_hwcaps);
 112 }
 113
 114 static inline void cpus_set_cap(unsigned int num)
 115 {
 116         if (num >= ARM64_NCAPS)
 117                 pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
 118                         num, ARM64_NCAPS);
 119         else
 120                 __set_bit(num, cpu_hwcaps);
 121 }
 122
 123 static inline int __attribute_const__
 124 cpuid_feature_extract_field_width(u64 features, int field, int width)
 125 {
 126         return (s64)(features << (64 - width - field)) >> (64 - width);
 127 }
 128
 129 static inline int __attribute_const__
 130 cpuid_feature_extract_field(u64 features, int field)
 131 {
 132         return cpuid_feature_extract_field_width(features, field, 4);
 133 }
 134
 135 static inline unsigned int __attribute_const__
 136 cpuid_feature_extract_unsigned_field_width(u64 features, int field, int width)
 137 {
 138         return (u64)(features << (64 - width - field)) >> (64 - width);
 139 }
 140
 141 static inline unsigned int __attribute_const__
 142 cpuid_feature_extract_unsigned_field(u64 features, int field)
 143 {
 144         return cpuid_feature_extract_unsigned_field_width(features, field, 4);
 145 }
 146
 147 static inline u64 arm64_ftr_mask(struct arm64_ftr_bits *ftrp)
 148 {
 149         return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);
 150 }
 151
 152 static inline s64 arm64_ftr_value(struct arm64_ftr_bits *ftrp, u64 val)
 153 {
 154         return ftrp->sign ?
 155                 cpuid_feature_extract_field_width(val, ftrp->shift, ftrp->width) :
 156                 cpuid_feature_extract_unsigned_field_width(val, ftrp->shift, ftrp->width);
 157 }
 158
 159 static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0)
 160 {
 161         return cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL_SHIFT) == 0x1 ||
 162                 cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL0_SHIFT) == 0x1;
 163 }
 164
 165 void __init setup_cpu_features(void);
 166
 167 void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
 168                             const char *info);
 169 void check_local_cpu_errata(void);
 170
 171 #ifdef CONFIG_HOTPLUG_CPU
 172 void verify_local_cpu_capabilities(void);
 173 #else
 174 static inline void verify_local_cpu_capabilities(void)
 175 {
 176 }
 177 #endif
 178
 179 u64 read_system_reg(u32 id);
 180
 181 static inline bool cpu_supports_mixed_endian_el0(void)
 182 {
 183         return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1));
 184 }
 185
 186 static inline bool system_supports_mixed_endian_el0(void)
 187 {
 188         return id_aa64mmfr0_mixed_endian_el0(read_system_reg(SYS_ID_AA64MMFR0_EL1));
 189 }
 190
 191 #endif /* __ASSEMBLY__ */
 192
 193 #endif