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 
27 #define ARM64_NCAPS				2
28 
29 #ifndef __ASSEMBLY__
30 
31 extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
32 
33 static inline bool cpu_have_feature(unsigned int num)
34 {
35 	return elf_hwcap & (1UL << num);
36 }
37 
38 static inline bool cpus_have_cap(unsigned int num)
39 {
40 	if (num >= ARM64_NCAPS)
41 		return false;
42 	return test_bit(num, cpu_hwcaps);
43 }
44 
45 static inline void cpus_set_cap(unsigned int num)
46 {
47 	if (num >= ARM64_NCAPS)
48 		pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
49 			num, ARM64_NCAPS);
50 	else
51 		__set_bit(num, cpu_hwcaps);
52 }
53 
54 void check_local_cpu_errata(void);
55 bool cpu_supports_mixed_endian_el0(void);
56 bool system_supports_mixed_endian_el0(void);
57 
58 #endif /* __ASSEMBLY__ */
59 
60 #endif
61