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 NCAPS                   0
  25
  26 extern DECLARE_BITMAP(cpu_hwcaps, NCAPS);
  27
  28 static inline bool cpu_have_feature(unsigned int num)
  29 {
  30         return elf_hwcap & (1UL << num);
  31 }
  32
  33 static inline bool cpus_have_cap(unsigned int num)
  34 {
  35         if (num >= NCAPS)
  36                 return false;
  37         return test_bit(num, cpu_hwcaps);
  38 }
  39
  40 static inline void cpus_set_cap(unsigned int num)
  41 {
  42         if (num >= NCAPS)
  43                 pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
  44                         num, NCAPS);
  45         else
  46                 __set_bit(num, cpu_hwcaps);
  47 }
  48
  49 void check_local_cpu_errata(void);
  50
  51 #endif