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