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
  14 /*
  15  * In the arm64 world (as in the ARM world), elf_hwcap is used both internally
  16  * in the kernel and for user space to keep track of which optional features
  17  * are supported by the current system. So let's map feature 'x' to HWCAP_x.
  18  * Note that HWCAP_x constants are bit fields so we need to take the log.
  19  */
  20
  21 #define MAX_CPU_FEATURES        (8 * sizeof(elf_hwcap))
  22 #define cpu_feature(x)          ilog2(HWCAP_ ## x)
  23
  24 #define ARM64_WORKAROUND_CLEAN_CACHE            0
  25 #define ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE    1
  26 #define ARM64_WORKAROUND_845719                 2
  27 #define ARM64_HAS_SYSREG_GIC_CPUIF              3
  28
  29 #define ARM64_NCAPS                             4
  30
  31 #ifndef __ASSEMBLY__
  32
  33 struct arm64_cpu_capabilities {
  34         const char *desc;
  35         u16 capability;
  36         bool (*matches)(const struct arm64_cpu_capabilities *);
  37         void (*enable)(void);
  38         union {
  39                 struct {        /* To be used for erratum handling only */
  40                         u32 midr_model;
  41                         u32 midr_range_min, midr_range_max;
  42                 };
  43
  44                 struct {        /* Feature register checking */
  45                         u64 register_mask;
  46                         u64 register_value;
  47                 };
  48         };
  49 };
  50
  51 extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
  52
  53 static inline bool cpu_have_feature(unsigned int num)
  54 {
  55         return elf_hwcap & (1UL << num);
  56 }
  57
  58 static inline bool cpus_have_cap(unsigned int num)
  59 {
  60         if (num >= ARM64_NCAPS)
  61                 return false;
  62         return test_bit(num, cpu_hwcaps);
  63 }
  64
  65 static inline void cpus_set_cap(unsigned int num)
  66 {
  67         if (num >= ARM64_NCAPS)
  68                 pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
  69                         num, ARM64_NCAPS);
  70         else
  71                 __set_bit(num, cpu_hwcaps);
  72 }
  73
  74 static inline int __attribute_const__ cpuid_feature_extract_field(u64 features,
  75                                                                   int field)
  76 {
  77         return (s64)(features << (64 - 4 - field)) >> (64 - 4);
  78 }
  79
  80
  81 void check_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
  82                             const char *info);
  83 void check_local_cpu_errata(void);
  84 void check_local_cpu_features(void);
  85 bool cpu_supports_mixed_endian_el0(void);
  86 bool system_supports_mixed_endian_el0(void);
  87
  88 #endif /* __ASSEMBLY__ */
  89
  90 #endif