2 * Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org>
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.
9 #ifndef __ASM_CPUFEATURE_H
10 #define __ASM_CPUFEATURE_H
12 #include <asm/hwcap.h>
13 #include <asm/sysreg.h>
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.
22 #define MAX_CPU_FEATURES (8 * sizeof(elf_hwcap))
23 #define cpu_feature(x) ilog2(HWCAP_ ## x)
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
36 #include <linux/kernel.h>
38 /* CPU feature register tracking */
40 FTR_EXACT, /* Use a predefined safe value */
41 FTR_LOWER_SAFE, /* Smaller value is safe */
42 FTR_HIGHER_SAFE,/* Bigger value is safe */
45 #define FTR_STRICT true /* SANITY check strict matching required */
46 #define FTR_NONSTRICT false /* SANITY check ignored */
48 struct arm64_ftr_bits {
49 bool strict; /* CPU Sanity check: strict matching required ? */
53 s64 safe_val; /* safe value for discrete features */
57 * @arm64_ftr_reg - Feature register
58 * @strict_mask Bits which should match across all CPUs for sanity.
59 * @sys_val Safe value across the CPUs (system view)
61 struct arm64_ftr_reg {
66 struct arm64_ftr_bits *ftr_bits;
69 struct arm64_cpu_capabilities {
72 bool (*matches)(const struct arm64_cpu_capabilities *);
73 void (*enable)(void *); /* Called on all active CPUs */
75 struct { /* To be used for erratum handling only */
77 u32 midr_range_min, midr_range_max;
80 struct { /* Feature register checking */
90 extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
92 static inline bool cpu_have_feature(unsigned int num)
94 return elf_hwcap & (1UL << num);
97 static inline bool cpus_have_cap(unsigned int num)
99 if (num >= ARM64_NCAPS)
101 return test_bit(num, cpu_hwcaps);
104 static inline void cpus_set_cap(unsigned int num)
106 if (num >= ARM64_NCAPS)
107 pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
110 __set_bit(num, cpu_hwcaps);
113 static inline int __attribute_const__
114 cpuid_feature_extract_field_width(u64 features, int field, int width)
116 return (s64)(features << (64 - width - field)) >> (64 - width);
119 static inline int __attribute_const__
120 cpuid_feature_extract_field(u64 features, int field)
122 return cpuid_feature_extract_field_width(features, field, 4);
125 static inline u64 arm64_ftr_mask(struct arm64_ftr_bits *ftrp)
127 return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);
130 static inline s64 arm64_ftr_value(struct arm64_ftr_bits *ftrp, u64 val)
132 return cpuid_feature_extract_field_width(val, ftrp->shift, ftrp->width);
135 static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0)
137 return cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL_SHIFT) == 0x1 ||
138 cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL0_SHIFT) == 0x1;
141 void __init setup_cpu_features(void);
143 void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
145 void check_local_cpu_errata(void);
147 #ifdef CONFIG_HOTPLUG_CPU
148 void verify_local_cpu_capabilities(void);
150 static inline void verify_local_cpu_capabilities(void)
155 u64 read_system_reg(u32 id);
157 static inline bool cpu_supports_mixed_endian_el0(void)
159 return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1));
162 static inline bool system_supports_mixed_endian_el0(void)
164 return id_aa64mmfr0_mixed_endian_el0(read_system_reg(SYS_ID_AA64MMFR0_EL1));
167 #endif /* __ASSEMBLY__ */