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 #define ARM64_HAS_PAN                           4
  29 #define ARM64_HAS_LSE_ATOMICS                   5
  30
  31 #define ARM64_NCAPS                             6
  32
  33 #ifndef __ASSEMBLY__
  34
  35 #include <linux/kernel.h>
  36
  37 struct arm64_cpu_capabilities {
  38         const char *desc;
  39         u16 capability;
  40         bool (*matches)(const struct arm64_cpu_capabilities *);
  41         void (*enable)(void);
  42         union {
  43                 struct {        /* To be used for erratum handling only */
  44                         u32 midr_model;
  45                         u32 midr_range_min, midr_range_max;
  46                 };
  47
  48                 struct {        /* Feature register checking */
  49                         int field_pos;
  50                         int min_field_value;
  51                 };
  52         };
  53 };
  54
  55 extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
  56
  57 static inline bool cpu_have_feature(unsigned int num)
  58 {
  59         return elf_hwcap & (1UL << num);
  60 }
  61
  62 static inline bool cpus_have_cap(unsigned int num)
  63 {
  64         if (num >= ARM64_NCAPS)
  65                 return false;
  66         return test_bit(num, cpu_hwcaps);
  67 }
  68
  69 static inline void cpus_set_cap(unsigned int num)
  70 {
  71         if (num >= ARM64_NCAPS)
  72                 pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
  73                         num, ARM64_NCAPS);
  74         else
  75                 __set_bit(num, cpu_hwcaps);
  76 }
  77
  78 static inline int __attribute_const__ cpuid_feature_extract_field(u64 features,
  79                                                                   int field)
  80 {
  81         return (s64)(features << (64 - 4 - field)) >> (64 - 4);
  82 }
  83
  84
  85 void check_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
  86                             const char *info);
  87 void check_local_cpu_errata(void);
  88 void check_local_cpu_features(void);
  89 bool cpu_supports_mixed_endian_el0(void);
  90 bool system_supports_mixed_endian_el0(void);
  91
  92 #endif /* __ASSEMBLY__ */
  93
  94 #endif