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 #define ARM64_WORKAROUND_CAVIUM_27456           8
  34
  35 #define ARM64_NCAPS                             9
  36
  37 #ifndef __ASSEMBLY__
  38
  39 #include <linux/kernel.h>
  40
  41 /* CPU feature register tracking */
  42 enum ftr_type {
  43         FTR_EXACT,      /* Use a predefined safe value */
  44         FTR_LOWER_SAFE, /* Smaller value is safe */
  45         FTR_HIGHER_SAFE,/* Bigger value is safe */
  46 };
  47
  48 #define FTR_STRICT      true    /* SANITY check strict matching required */
  49 #define FTR_NONSTRICT   false   /* SANITY check ignored */
  50
  51 #define FTR_SIGNED      true    /* Value should be treated as signed */
  52 #define FTR_UNSIGNED    false   /* Value should be treated as unsigned */
  53
  54 struct arm64_ftr_bits {
  55         bool            sign;   /* Value is signed ? */
  56         bool            strict; /* CPU Sanity check: strict matching required ? */
  57         enum ftr_type   type;
  58         u8              shift;
  59         u8              width;
  60         s64             safe_val; /* safe value for discrete features */
  61 };
  62
  63 /*
  64  * @arm64_ftr_reg - Feature register
  65  * @strict_mask         Bits which should match across all CPUs for sanity.
  66  * @sys_val             Safe value across the CPUs (system view)
  67  */
  68 struct arm64_ftr_reg {
  69         u32                     sys_id;
  70         const char              *name;
  71         u64                     strict_mask;
  72         u64                     sys_val;
  73         struct arm64_ftr_bits   *ftr_bits;
  74 };
  75
  76 struct arm64_cpu_capabilities {
  77         const char *desc;
  78         u16 capability;
  79         bool (*matches)(const struct arm64_cpu_capabilities *);
  80         int (*enable)(void *);          /* Called on all active CPUs */
  81         union {
  82                 struct {        /* To be used for erratum handling only */
  83                         u32 midr_model;
  84                         u32 midr_range_min, midr_range_max;
  85                 };
  86
  87                 struct {        /* Feature register checking */
  88                         u32 sys_reg;
  89                         int field_pos;
  90                         int min_field_value;
  91                         int hwcap_type;
  92                         unsigned long hwcap;
  93                 };
  94         };
  95 };
  96
  97 extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
  98
  99 static inline bool cpu_have_feature(unsigned int num)
 100 {
 101         return elf_hwcap & (1UL << num);
 102 }
 103
 104 static inline bool cpus_have_cap(unsigned int num)
 105 {
 106         if (num >= ARM64_NCAPS)
 107                 return false;
 108         return test_bit(num, cpu_hwcaps);
 109 }
 110
 111 static inline void cpus_set_cap(unsigned int num)
 112 {
 113         if (num >= ARM64_NCAPS)
 114                 pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
 115                         num, ARM64_NCAPS);
 116         else
 117                 __set_bit(num, cpu_hwcaps);
 118 }
 119
 120 static inline int __attribute_const__
 121 cpuid_feature_extract_field_width(u64 features, int field, int width)
 122 {
 123         return (s64)(features << (64 - width - field)) >> (64 - width);
 124 }
 125
 126 static inline int __attribute_const__
 127 cpuid_feature_extract_field(u64 features, int field)
 128 {
 129         return cpuid_feature_extract_field_width(features, field, 4);
 130 }
 131
 132 static inline unsigned int __attribute_const__
 133 cpuid_feature_extract_unsigned_field_width(u64 features, int field, int width)
 134 {
 135         return (u64)(features << (64 - width - field)) >> (64 - width);
 136 }
 137
 138 static inline unsigned int __attribute_const__
 139 cpuid_feature_extract_unsigned_field(u64 features, int field)
 140 {
 141         return cpuid_feature_extract_unsigned_field_width(features, field, 4);
 142 }
 143
 144 static inline u64 arm64_ftr_mask(struct arm64_ftr_bits *ftrp)
 145 {
 146         return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);
 147 }
 148
 149 static inline s64 arm64_ftr_value(struct arm64_ftr_bits *ftrp, u64 val)
 150 {
 151         return ftrp->sign ?
 152                 cpuid_feature_extract_field_width(val, ftrp->shift, ftrp->width) :
 153                 cpuid_feature_extract_unsigned_field_width(val, ftrp->shift, ftrp->width);
 154 }
 155
 156 static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0)
 157 {
 158         return cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL_SHIFT) == 0x1 ||
 159                 cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL0_SHIFT) == 0x1;
 160 }
 161
 162 void __init setup_cpu_features(void);
 163
 164 void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
 165                             const char *info);
 166 void check_local_cpu_errata(void);
 167
 168 #ifdef CONFIG_HOTPLUG_CPU
 169 void verify_local_cpu_capabilities(void);
 170 #else
 171 static inline void verify_local_cpu_capabilities(void)
 172 {
 173 }
 174 #endif
 175
 176 u64 read_system_reg(u32 id);
 177
 178 static inline bool cpu_supports_mixed_endian_el0(void)
 179 {
 180         return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1));
 181 }
 182
 183 static inline bool system_supports_mixed_endian_el0(void)
 184 {
 185         return id_aa64mmfr0_mixed_endian_el0(read_system_reg(SYS_ID_AA64MMFR0_EL1));
 186 }
 187
 188 #endif /* __ASSEMBLY__ */
 189
 190 #endif