LXR linux/include/linux/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 __LINUX_CPUFEATURE_H
  10#define __LINUX_CPUFEATURE_H
  11
  12#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
  13
  14#include <linux/init.h>
  15#include <linux/mod_devicetable.h>
  16#include <asm/cpufeature.h>
  17
  18/*
  19 * Macros imported from <asm/cpufeature.h>:
  20 * - cpu_feature(x)             ordinal value of feature called 'x'
  21 * - cpu_have_feature(u32 n)    whether feature #n is available
  22 * - MAX_CPU_FEATURES           upper bound for feature ordinal values
  23 * Optional:
  24 * - CPU_FEATURE_TYPEFMT        format string fragment for printing the cpu type
  25 * - CPU_FEATURE_TYPEVAL        set of values matching the format string above
  26 */
  27
  28#ifndef CPU_FEATURE_TYPEFMT
  29#define CPU_FEATURE_TYPEFMT     "%s"
  30#endif
  31
  32#ifndef CPU_FEATURE_TYPEVAL
  33#define CPU_FEATURE_TYPEVAL     ELF_PLATFORM
  34#endif
  35
  36/*
  37 * Use module_cpu_feature_match(feature, module_init_function) to
  38 * declare that
  39 * a) the module shall be probed upon discovery of CPU feature 'feature'
  40 *    (typically at boot time using udev)
  41 * b) the module must not be loaded if CPU feature 'feature' is not present
  42 *    (not even by manual insmod).
  43 *
  44 * For a list of legal values for 'feature', please consult the file
  45 * 'asm/cpufeature.h' of your favorite architecture.
  46 */
  47#define module_cpu_feature_match(x, __initfunc)                 \
  48static struct cpu_feature const cpu_feature_match_ ## x[] =     \
  49        { { .feature = cpu_feature(x) }, { } };                 \
  50MODULE_DEVICE_TABLE(cpu, cpu_feature_match_ ## x);              \
  51                                                                \
  52static int __init cpu_feature_match_ ## x ## _init(void)        \
  53{                                                               \
  54        if (!cpu_have_feature(cpu_feature(x)))                  \
  55                return -ENODEV;                                 \
  56        return __initfunc();                                    \
  57}                                                               \
  58module_init(cpu_feature_match_ ## x ## _init)
  59
  60#endif
  61#endif
  62