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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 #include <asm/sysreg.h>
14
15 /*
16  * In the arm64 world (as in the ARM world), elf_hwcap is used both internally
17  * in the kernel and for user space to keep track of which optional features
18  * are supported by the current system. So let's map feature 'x' to HWCAP_x.
19  * Note that HWCAP_x constants are bit fields so we need to take the log.
20  */
21
22 #define MAX_CPU_FEATURES        (8 * sizeof(elf_hwcap))
23 #define cpu_feature(x)          ilog2(HWCAP_ ## x)
24
25 #define ARM64_WORKAROUND_CLEAN_CACHE            0
26 #define ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE    1
27 #define ARM64_WORKAROUND_845719                 2
28 #define ARM64_HAS_SYSREG_GIC_CPUIF              3
29 #define ARM64_HAS_PAN                           4
30 #define ARM64_HAS_LSE_ATOMICS                   5
31 #define ARM64_WORKAROUND_CAVIUM_23154           6
32 #define ARM64_WORKAROUND_834220                 7
33
34 #define ARM64_NCAPS                             8
35
36 #ifndef __ASSEMBLY__
37
38 #include <linux/kernel.h>
39
40 /* CPU feature register tracking */
41 enum ftr_type {
42         FTR_EXACT,      /* Use a predefined safe value */
43         FTR_LOWER_SAFE, /* Smaller value is safe */
44         FTR_HIGHER_SAFE,/* Bigger value is safe */
45 };
46
47 #define FTR_STRICT      true    /* SANITY check strict matching required */
48 #define FTR_NONSTRICT   false   /* SANITY check ignored */
49
50 #define FTR_SIGNED      true    /* Value should be treated as signed */
51 #define FTR_UNSIGNED    false   /* Value should be treated as unsigned */
52
53 struct arm64_ftr_bits {
54         bool            sign;   /* Value is signed ? */
55         bool            strict; /* CPU Sanity check: strict matching required ? */
56         enum ftr_type   type;
57         u8              shift;
58         u8              width;
59         s64             safe_val; /* safe value for discrete features */
60 };
61
62 /*
63  * @arm64_ftr_reg - Feature register
64  * @strict_mask         Bits which should match across all CPUs for sanity.
65  * @sys_val             Safe value across the CPUs (system view)
66  */
67 struct arm64_ftr_reg {
68         u32                     sys_id;
69         const char              *name;
70         u64                     strict_mask;
71         u64                     sys_val;
72         struct arm64_ftr_bits   *ftr_bits;
73 };
74
75 struct arm64_cpu_capabilities {
76         const char *desc;
77         u16 capability;
78         bool (*matches)(const struct arm64_cpu_capabilities *);
79         void (*enable)(void *);         /* Called on all active CPUs */
80         union {
81                 struct {        /* To be used for erratum handling only */
82                         u32 midr_model;
83                         u32 midr_range_min, midr_range_max;
84                 };
85
86                 struct {        /* Feature register checking */
87                         u32 sys_reg;
88                         int field_pos;
89                         int min_field_value;
90                         int hwcap_type;
91                         unsigned long hwcap;
92                 };
93         };
94 };
95
96 extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
97
98 static inline bool cpu_have_feature(unsigned int num)
99 {
100         return elf_hwcap & (1UL << num);
101 }
102
103 static inline bool cpus_have_cap(unsigned int num)
104 {
105         if (num >= ARM64_NCAPS)
106                 return false;
107         return test_bit(num, cpu_hwcaps);
108 }
109
110 static inline void cpus_set_cap(unsigned int num)
111 {
112         if (num >= ARM64_NCAPS)
113                 pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
114                         num, ARM64_NCAPS);
115         else
116                 __set_bit(num, cpu_hwcaps);
117 }
118
119 static inline int __attribute_const__
120 cpuid_feature_extract_field_width(u64 features, int field, int width)
121 {
122         return (s64)(features << (64 - width - field)) >> (64 - width);
123 }
124
125 static inline int __attribute_const__
126 cpuid_feature_extract_field(u64 features, int field)
127 {
128         return cpuid_feature_extract_field_width(features, field, 4);
129 }
130
131 static inline unsigned int __attribute_const__
132 cpuid_feature_extract_unsigned_field_width(u64 features, int field, int width)
133 {
134         return (u64)(features << (64 - width - field)) >> (64 - width);
135 }
136
137 static inline unsigned int __attribute_const__
138 cpuid_feature_extract_unsigned_field(u64 features, int field)
139 {
140         return cpuid_feature_extract_unsigned_field_width(features, field, 4);
141 }
142
143 static inline u64 arm64_ftr_mask(struct arm64_ftr_bits *ftrp)
144 {
145         return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);
146 }
147
148 static inline s64 arm64_ftr_value(struct arm64_ftr_bits *ftrp, u64 val)
149 {
150         return ftrp->sign ?
151                 cpuid_feature_extract_field_width(val, ftrp->shift, ftrp->width) :
152                 cpuid_feature_extract_unsigned_field_width(val, ftrp->shift, ftrp->width);
153 }
154
155 static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0)
156 {
157         return cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL_SHIFT) == 0x1 ||
158                 cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL0_SHIFT) == 0x1;
159 }
160
161 void __init setup_cpu_features(void);
162
163 void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
164                             const char *info);
165 void check_local_cpu_errata(void);
166
167 #ifdef CONFIG_HOTPLUG_CPU
168 void verify_local_cpu_capabilities(void);
169 #else
170 static inline void verify_local_cpu_capabilities(void)
171 {
172 }
173 #endif
174
175 u64 read_system_reg(u32 id);
176
177 static inline bool cpu_supports_mixed_endian_el0(void)
178 {
179         return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1));
180 }
181
182 static inline bool system_supports_mixed_endian_el0(void)
183 {
184         return id_aa64mmfr0_mixed_endian_el0(read_system_reg(SYS_ID_AA64MMFR0_EL1));
185 }
186
187 #endif /* __ASSEMBLY__ */
188
189 #endif