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/cpucaps.h>
13 #include <asm/hwcap.h>
14 #include <asm/sysreg.h>
17 * In the arm64 world (as in the ARM world), elf_hwcap is used both internally
18 * in the kernel and for user space to keep track of which optional features
19 * are supported by the current system. So let's map feature 'x' to HWCAP_x.
20 * Note that HWCAP_x constants are bit fields so we need to take the log.
23 #define MAX_CPU_FEATURES (8 * sizeof(elf_hwcap))
24 #define cpu_feature(x) ilog2(HWCAP_ ## x)
28 #include <linux/bug.h>
29 #include <linux/jump_label.h>
30 #include <linux/kernel.h>
32 /* CPU feature register tracking */
34 FTR_EXACT, /* Use a predefined safe value */
35 FTR_LOWER_SAFE, /* Smaller value is safe */
36 FTR_HIGHER_SAFE, /* Bigger value is safe */
37 FTR_HIGHER_OR_ZERO_SAFE, /* Bigger value is safe, but 0 is biggest */
40 #define FTR_STRICT true /* SANITY check strict matching required */
41 #define FTR_NONSTRICT false /* SANITY check ignored */
43 #define FTR_SIGNED true /* Value should be treated as signed */
44 #define FTR_UNSIGNED false /* Value should be treated as unsigned */
46 struct arm64_ftr_bits {
47 bool sign; /* Value is signed ? */
48 bool strict; /* CPU Sanity check: strict matching required ? */
52 s64 safe_val; /* safe value for FTR_EXACT features */
56 * @arm64_ftr_reg - Feature register
57 * @strict_mask Bits which should match across all CPUs for sanity.
58 * @sys_val Safe value across the CPUs (system view)
60 struct arm64_ftr_reg {
64 const struct arm64_ftr_bits *ftr_bits;
67 extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0;
69 /* scope of capability check */
75 struct arm64_cpu_capabilities {
78 int def_scope; /* default scope */
79 bool (*matches)(const struct arm64_cpu_capabilities *caps, int scope);
80 int (*enable)(void *); /* Called on all active CPUs */
82 struct { /* To be used for erratum handling only */
84 u32 midr_range_min, midr_range_max;
87 struct { /* Feature register checking */
98 extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
99 extern struct static_key_false cpu_hwcap_keys[ARM64_NCAPS];
100 extern struct static_key_false arm64_const_caps_ready;
102 bool this_cpu_has_cap(unsigned int cap);
104 static inline bool cpu_have_feature(unsigned int num)
106 return elf_hwcap & (1UL << num);
109 /* System capability check for constant caps */
110 static inline bool __cpus_have_const_cap(int num)
112 if (num >= ARM64_NCAPS)
114 return static_branch_unlikely(&cpu_hwcap_keys[num]);
117 static inline bool cpus_have_cap(unsigned int num)
119 if (num >= ARM64_NCAPS)
121 return test_bit(num, cpu_hwcaps);
124 static inline bool cpus_have_const_cap(int num)
126 if (static_branch_likely(&arm64_const_caps_ready))
127 return __cpus_have_const_cap(num);
129 return cpus_have_cap(num);
132 static inline void cpus_set_cap(unsigned int num)
134 if (num >= ARM64_NCAPS) {
135 pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
138 __set_bit(num, cpu_hwcaps);
142 static inline int __attribute_const__
143 cpuid_feature_extract_signed_field_width(u64 features, int field, int width)
145 return (s64)(features << (64 - width - field)) >> (64 - width);
148 static inline int __attribute_const__
149 cpuid_feature_extract_signed_field(u64 features, int field)
151 return cpuid_feature_extract_signed_field_width(features, field, 4);
154 static inline unsigned int __attribute_const__
155 cpuid_feature_extract_unsigned_field_width(u64 features, int field, int width)
157 return (u64)(features << (64 - width - field)) >> (64 - width);
160 static inline unsigned int __attribute_const__
161 cpuid_feature_extract_unsigned_field(u64 features, int field)
163 return cpuid_feature_extract_unsigned_field_width(features, field, 4);
166 static inline u64 arm64_ftr_mask(const struct arm64_ftr_bits *ftrp)
168 return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);
171 static inline int __attribute_const__
172 cpuid_feature_extract_field(u64 features, int field, bool sign)
175 cpuid_feature_extract_signed_field(features, field) :
176 cpuid_feature_extract_unsigned_field(features, field);
179 static inline s64 arm64_ftr_value(const struct arm64_ftr_bits *ftrp, u64 val)
181 return (s64)cpuid_feature_extract_field(val, ftrp->shift, ftrp->sign);
184 static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0)
186 return cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_BIGENDEL_SHIFT) == 0x1 ||
187 cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_BIGENDEL0_SHIFT) == 0x1;
190 static inline bool id_aa64pfr0_32bit_el0(u64 pfr0)
192 u32 val = cpuid_feature_extract_unsigned_field(pfr0, ID_AA64PFR0_EL0_SHIFT);
194 return val == ID_AA64PFR0_EL0_32BIT_64BIT;
197 void __init setup_cpu_features(void);
199 void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
201 void enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps);
202 void check_local_cpu_capabilities(void);
204 void update_cpu_errata_workarounds(void);
205 void __init enable_errata_workarounds(void);
206 void verify_local_cpu_errata_workarounds(void);
208 u64 read_system_reg(u32 id);
210 static inline bool cpu_supports_mixed_endian_el0(void)
212 return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1));
215 static inline bool system_supports_32bit_el0(void)
217 return cpus_have_const_cap(ARM64_HAS_32BIT_EL0);
220 static inline bool system_supports_mixed_endian_el0(void)
222 return id_aa64mmfr0_mixed_endian_el0(read_system_reg(SYS_ID_AA64MMFR0_EL1));
225 #define ARM64_SSBD_UNKNOWN -1
226 #define ARM64_SSBD_FORCE_DISABLE 0
227 #define ARM64_SSBD_KERNEL 1
228 #define ARM64_SSBD_FORCE_ENABLE 2
229 #define ARM64_SSBD_MITIGATED 3
231 static inline int arm64_get_ssbd_state(void)
233 #ifdef CONFIG_ARM64_SSBD
234 extern int ssbd_state;
237 return ARM64_SSBD_UNKNOWN;
241 #ifdef CONFIG_ARM64_SSBD
242 void arm64_set_ssbd_mitigation(bool state);
244 static inline void arm64_set_ssbd_mitigation(bool state) {}
247 #endif /* __ASSEMBLY__ */