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
31 #define ARM64_WORKAROUND_CAVIUM_23154 6
32 #define ARM64_WORKAROUND_834220 7
33 #define ARM64_HAS_NO_HW_PREFETCH 8
34 #define ARM64_HAS_UAO 9
35 #define ARM64_ALT_PAN_NOT_UAO 10
37 #define ARM64_WORKAROUND_CAVIUM_27456 11
38 #define ARM64_HAS_VIRT_HOST_EXTN 12
39 #define ARM64_HARDEN_BRANCH_PREDICTOR 13
40 #define ARM64_UNMAP_KERNEL_AT_EL0 14
41 #define ARM64_HAS_32BIT_EL0 15
42 #define ARM64_NCAPS 16
46 #include <linux/kernel.h>
48 extern const char *machine_name;
50 /* CPU feature register tracking */
52 FTR_EXACT, /* Use a predefined safe value */
53 FTR_LOWER_SAFE, /* Smaller value is safe */
54 FTR_HIGHER_SAFE,/* Bigger value is safe */
57 #define FTR_STRICT true /* SANITY check strict matching required */
58 #define FTR_NONSTRICT false /* SANITY check ignored */
60 #define FTR_SIGNED true /* Value should be treated as signed */
61 #define FTR_UNSIGNED false /* Value should be treated as unsigned */
63 struct arm64_ftr_bits {
64 bool sign; /* Value is signed ? */
65 bool strict; /* CPU Sanity check: strict matching required ? */
69 s64 safe_val; /* safe value for discrete features */
73 * @arm64_ftr_reg - Feature register
74 * @strict_mask Bits which should match across all CPUs for sanity.
75 * @sys_val Safe value across the CPUs (system view)
77 struct arm64_ftr_reg {
82 struct arm64_ftr_bits *ftr_bits;
85 struct arm64_cpu_capabilities {
88 bool (*matches)(const struct arm64_cpu_capabilities *);
89 int (*enable)(void *); /* Called on all active CPUs */
91 struct { /* To be used for erratum handling only */
93 u32 midr_range_min, midr_range_max;
96 struct { /* Feature register checking */
106 extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
108 static inline bool cpu_have_feature(unsigned int num)
110 return elf_hwcap & (1UL << num);
113 static inline bool cpus_have_cap(unsigned int num)
115 if (num >= ARM64_NCAPS)
117 return test_bit(num, cpu_hwcaps);
120 static inline void cpus_set_cap(unsigned int num)
122 if (num >= ARM64_NCAPS)
123 pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
126 __set_bit(num, cpu_hwcaps);
129 static inline int __attribute_const__
130 cpuid_feature_extract_field_width(u64 features, int field, int width)
132 return (s64)(features << (64 - width - field)) >> (64 - width);
135 static inline int __attribute_const__
136 cpuid_feature_extract_field(u64 features, int field)
138 return cpuid_feature_extract_field_width(features, field, 4);
141 static inline unsigned int __attribute_const__
142 cpuid_feature_extract_unsigned_field_width(u64 features, int field, int width)
144 return (u64)(features << (64 - width - field)) >> (64 - width);
147 static inline unsigned int __attribute_const__
148 cpuid_feature_extract_unsigned_field(u64 features, int field)
150 return cpuid_feature_extract_unsigned_field_width(features, field, 4);
153 static inline u64 arm64_ftr_mask(struct arm64_ftr_bits *ftrp)
155 return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);
158 static inline s64 arm64_ftr_value(struct arm64_ftr_bits *ftrp, u64 val)
161 cpuid_feature_extract_field_width(val, ftrp->shift, ftrp->width) :
162 cpuid_feature_extract_unsigned_field_width(val, ftrp->shift, ftrp->width);
165 static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0)
167 return cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL_SHIFT) == 0x1 ||
168 cpuid_feature_extract_field(mmfr0, ID_AA64MMFR0_BIGENDEL0_SHIFT) == 0x1;
171 void __init setup_cpu_features(void);
173 void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
175 void enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps);
176 void check_local_cpu_errata(void);
177 void __init enable_errata_workarounds(void);
179 #ifdef CONFIG_HOTPLUG_CPU
180 void verify_local_cpu_capabilities(void);
182 static inline void verify_local_cpu_capabilities(void)
187 u64 read_system_reg(u32 id);
189 static inline bool cpu_supports_mixed_endian_el0(void)
191 return id_aa64mmfr0_mixed_endian_el0(read_cpuid(SYS_ID_AA64MMFR0_EL1));
194 static inline bool system_supports_32bit_el0(void)
196 return cpus_have_cap(ARM64_HAS_32BIT_EL0);
199 static inline bool system_supports_mixed_endian_el0(void)
201 return id_aa64mmfr0_mixed_endian_el0(read_system_reg(SYS_ID_AA64MMFR0_EL1));
204 static inline bool system_uses_ttbr0_pan(void)
206 return IS_ENABLED(CONFIG_ARM64_SW_TTBR0_PAN) &&
207 !cpus_have_cap(ARM64_HAS_PAN);
210 #endif /* __ASSEMBLY__ */