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
  33 #define ARM64_NCAPS                             7
  34
  35 #ifndef __ASSEMBLY__
  36
  37 #include <linux/kernel.h>
  38
  39 /* CPU feature register tracking */
  40 enum ftr_type {
  41         FTR_EXACT,      /* Use a predefined safe value */
  42         FTR_LOWER_SAFE, /* Smaller value is safe */
  43         FTR_HIGHER_SAFE,/* Bigger value is safe */
  44 };
  45
  46 #define FTR_STRICT      true    /* SANITY check strict matching required */
  47 #define FTR_NONSTRICT   false   /* SANITY check ignored */
  48
  49 struct arm64_ftr_bits {
  50         bool            strict;   /* CPU Sanity check: strict matching required ? */
  51         enum ftr_type   type;
  52         u8              shift;
  53         u8              width;
  54         s64             safe_val; /* safe value for discrete features */
  55 };
  56
  57 /*
  58  * @arm64_ftr_reg - Feature register
  59  * @strict_mask         Bits which should match across all CPUs for sanity.
  60  * @sys_val             Safe value across the CPUs (system view)
  61  */
  62 struct arm64_ftr_reg {
  63         u32                     sys_id;
  64         const char              *name;
  65         u64                     strict_mask;
  66         u64                     sys_val;
  67         struct arm64_ftr_bits   *ftr_bits;
  68 };
  69
  70 struct arm64_cpu_capabilities {
  71         const char *desc;
  72         u16 capability;
  73         bool (*matches)(const struct arm64_cpu_capabilities *);
  74         void (*enable)(void *);         /* Called on all active CPUs */
  75         union {
  76                 struct {        /* To be used for erratum handling only */
  77                         u32 midr_model;
  78                         u32 midr_range_min, midr_range_max;
  79                 };
  80
  81                 struct {        /* Feature register checking */
  82                         u32 sys_reg;
  83                         int field_pos;
  84                         int min_field_value;
  85                         int hwcap_type;
  86                         unsigned long hwcap;
  87                 };
  88         };
  89 };
  90
  91 extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
  92
  93 static inline bool cpu_have_feature(unsigned int num)
  94 {
  95         return elf_hwcap & (1UL << num);
  96 }
  97
  98 static inline bool cpus_have_cap(unsigned int num)
  99 {
 100         if (num >= ARM64_NCAPS)
 101                 return false;
 102         return test_bit(num, cpu_hwcaps);
 103 }
 104
 105 static inline void cpus_set_cap(unsigned int num)
 106 {
 107         if (num >= ARM64_NCAPS)
 108                 pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
 109                         num, ARM64_NCAPS);
 110         else
 111                 __set_bit(num, cpu_hwcaps);
 112 }
 113
 114 static inline int __attribute_const__
 115 cpuid_feature_extract_field_width(u64 features, int field, int width)
 116 {
 117         return (s64)(features << (64 - width - field)) >> (64 - width);
 118 }
 119
 120 static inline int __attribute_const__
 121 cpuid_feature_extract_field(u64 features, int field)
 122 {
 123         return cpuid_feature_extract_field_width(features, field, 4);
 124 }
 125
 126 static inline u64 arm64_ftr_mask(struct arm64_ftr_bits *ftrp)
 127 {
 128         return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);
 129 }
 130
 131 static inline s64 arm64_ftr_value(struct arm64_ftr_bits *ftrp, u64 val)
 132 {
 133         return cpuid_feature_extract_field_width(val, ftrp->shift, ftrp->width);
 134 }
 135
 136 static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0)
 137 {
 138         return cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL_SHIFT) == 0x1 ||
 139                 cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL0_SHIFT) == 0x1;
 140 }
 141
 142 void __init setup_cpu_features(void);
 143
 144 void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
 145                             const char *info);
 146 void check_local_cpu_errata(void);
 147
 148 #ifdef CONFIG_HOTPLUG_CPU
 149 void verify_local_cpu_capabilities(void);
 150 #else
 151 static inline void verify_local_cpu_capabilities(void)
 152 {
 153 }
 154 #endif
 155
 156 u64 read_system_reg(u32 id);
 157
 158 static inline bool cpu_supports_mixed_endian_el0(void)
 159 {
 160         return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1));
 161 }
 162
 163 static inline bool system_supports_mixed_endian_el0(void)
 164 {
 165         return id_aa64mmfr0_mixed_endian_el0(read_system_reg(SYS_ID_AA64MMFR0_EL1));
 166 }
 167
 168 #endif /* __ASSEMBLY__ */
 169
 170 #endif