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
28#define ARM64_NCAPS				3
29
30#ifndef __ASSEMBLY__
31
32struct arm64_cpu_capabilities {
33	const char *desc;
34	u16 capability;
35	bool (*matches)(const struct arm64_cpu_capabilities *);
36	union {
37		struct {	/* To be used for erratum handling only */
38			u32 midr_model;
39			u32 midr_range_min, midr_range_max;
40		};
41	};
42};
43
44extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
45
46static inline bool cpu_have_feature(unsigned int num)
47{
48	return elf_hwcap & (1UL << num);
49}
50
51static inline bool cpus_have_cap(unsigned int num)
52{
53	if (num >= ARM64_NCAPS)
54		return false;
55	return test_bit(num, cpu_hwcaps);
56}
57
58static inline void cpus_set_cap(unsigned int num)
59{
60	if (num >= ARM64_NCAPS)
61		pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
62			num, ARM64_NCAPS);
63	else
64		__set_bit(num, cpu_hwcaps);
65}
66
67void check_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
68			    const char *info);
69void check_local_cpu_errata(void);
70void check_local_cpu_features(void);
71bool cpu_supports_mixed_endian_el0(void);
72bool system_supports_mixed_endian_el0(void);
73
74#endif /* __ASSEMBLY__ */
75
76#endif
77