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
  32 #define ARM64_NCAPS                             6
  33
  34 #ifndef __ASSEMBLY__
  35
  36 #include <linux/kernel.h>
  37
  38 /* CPU feature register tracking */
  39 enum ftr_type {
  40         FTR_EXACT,      /* Use a predefined safe value */
  41         FTR_LOWER_SAFE, /* Smaller value is safe */
  42         FTR_HIGHER_SAFE,/* Bigger value is safe */
  43 };
  44
  45 #define FTR_STRICT      true    /* SANITY check strict matching required */
  46 #define FTR_NONSTRICT   false   /* SANITY check ignored */
  47
  48 struct arm64_ftr_bits {
  49         bool            strict;   /* CPU Sanity check: strict matching required ? */
  50         enum ftr_type   type;
  51         u8              shift;
  52         u8              width;
  53         s64             safe_val; /* safe value for discrete features */
  54 };
  55
  56 /*
  57  * @arm64_ftr_reg - Feature register
  58  * @strict_mask         Bits which should match across all CPUs for sanity.
  59  * @sys_val             Safe value across the CPUs (system view)
  60  */
  61 struct arm64_ftr_reg {
  62         u32                     sys_id;
  63         const char              *name;
  64         u64                     strict_mask;
  65         u64                     sys_val;
  66         struct arm64_ftr_bits   *ftr_bits;
  67 };
  68
  69 struct arm64_cpu_capabilities {
  70         const char *desc;
  71         u16 capability;
  72         bool (*matches)(const struct arm64_cpu_capabilities *);
  73         void (*enable)(void *);         /* Called on all active CPUs */
  74         union {
  75                 struct {        /* To be used for erratum handling only */
  76                         u32 midr_model;
  77                         u32 midr_range_min, midr_range_max;
  78                 };
  79
  80                 struct {        /* Feature register checking */
  81                         u32 sys_reg;
  82                         int field_pos;
  83                         int min_field_value;
  84                         int hwcap_type;
  85                         unsigned long hwcap;
  86                 };
  87         };
  88 };
  89
  90 extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
  91
  92 static inline bool cpu_have_feature(unsigned int num)
  93 {
  94         return elf_hwcap & (1UL << num);
  95 }
  96
  97 static inline bool cpus_have_cap(unsigned int num)
  98 {
  99         if (num >= ARM64_NCAPS)
 100                 return false;
 101         return test_bit(num, cpu_hwcaps);
 102 }
 103
 104 static inline void cpus_set_cap(unsigned int num)
 105 {
 106         if (num >= ARM64_NCAPS)
 107                 pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
 108                         num, ARM64_NCAPS);
 109         else
 110                 __set_bit(num, cpu_hwcaps);
 111 }
 112
 113 static inline int __attribute_const__
 114 cpuid_feature_extract_field_width(u64 features, int field, int width)
 115 {
 116         return (s64)(features << (64 - width - field)) >> (64 - width);
 117 }
 118
 119 static inline int __attribute_const__
 120 cpuid_feature_extract_field(u64 features, int field)
 121 {
 122         return cpuid_feature_extract_field_width(features, field, 4);
 123 }
 124
 125 static inline u64 arm64_ftr_mask(struct arm64_ftr_bits *ftrp)
 126 {
 127         return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);
 128 }
 129
 130 static inline s64 arm64_ftr_value(struct arm64_ftr_bits *ftrp, u64 val)
 131 {
 132         return cpuid_feature_extract_field_width(val, ftrp->shift, ftrp->width);
 133 }
 134
 135 static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0)
 136 {
 137         return cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL_SHIFT) == 0x1 ||
 138                 cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL0_SHIFT) == 0x1;
 139 }
 140
 141 void __init setup_cpu_features(void);
 142
 143 void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
 144                             const char *info);
 145 void check_local_cpu_errata(void);
 146
 147 #ifdef CONFIG_HOTPLUG_CPU
 148 void verify_local_cpu_capabilities(void);
 149 #else
 150 static inline void verify_local_cpu_capabilities(void)
 151 {
 152 }
 153 #endif
 154
 155 u64 read_system_reg(u32 id);
 156
 157 static inline bool cpu_supports_mixed_endian_el0(void)
 158 {
 159         return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1));
 160 }
 161
 162 static inline bool system_supports_mixed_endian_el0(void)
 163 {
 164         return id_aa64mmfr0_mixed_endian_el0(read_system_reg(SYS_ID_AA64MMFR0_EL1));
 165 }
 166
 167 #endif /* __ASSEMBLY__ */
 168
 169 #endif