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 
32 struct 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 
44 extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
45 
46 static inline bool cpu_have_feature(unsigned int num)
47 {
48 	return elf_hwcap & (1UL << num);
49 }
50 
51 static 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 
58 static 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 
67 void check_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
68 			    const char *info);
69 void check_local_cpu_errata(void);
70 void check_local_cpu_features(void);
71 bool cpu_supports_mixed_endian_el0(void);
72 bool system_supports_mixed_endian_el0(void);
73 
74 #endif /* __ASSEMBLY__ */
75 
76 #endif
77