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 __maybe_unused 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