xref: /openbmc/linux/arch/arm64/kernel/cpufeature.c (revision cce8ccca)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Contains CPU feature definitions
4  *
5  * Copyright (C) 2015 ARM Ltd.
6  */
7 
8 #define pr_fmt(fmt) "CPU features: " fmt
9 
10 #include <linux/bsearch.h>
11 #include <linux/cpumask.h>
12 #include <linux/crash_dump.h>
13 #include <linux/sort.h>
14 #include <linux/stop_machine.h>
15 #include <linux/types.h>
16 #include <linux/mm.h>
17 #include <linux/cpu.h>
18 #include <asm/cpu.h>
19 #include <asm/cpufeature.h>
20 #include <asm/cpu_ops.h>
21 #include <asm/fpsimd.h>
22 #include <asm/mmu_context.h>
23 #include <asm/processor.h>
24 #include <asm/sysreg.h>
25 #include <asm/traps.h>
26 #include <asm/virt.h>
27 
28 /* Kernel representation of AT_HWCAP and AT_HWCAP2 */
29 static unsigned long elf_hwcap __read_mostly;
30 
31 #ifdef CONFIG_COMPAT
32 #define COMPAT_ELF_HWCAP_DEFAULT	\
33 				(COMPAT_HWCAP_HALF|COMPAT_HWCAP_THUMB|\
34 				 COMPAT_HWCAP_FAST_MULT|COMPAT_HWCAP_EDSP|\
35 				 COMPAT_HWCAP_TLS|COMPAT_HWCAP_VFP|\
36 				 COMPAT_HWCAP_VFPv3|COMPAT_HWCAP_VFPv4|\
37 				 COMPAT_HWCAP_NEON|COMPAT_HWCAP_IDIV|\
38 				 COMPAT_HWCAP_LPAE)
39 unsigned int compat_elf_hwcap __read_mostly = COMPAT_ELF_HWCAP_DEFAULT;
40 unsigned int compat_elf_hwcap2 __read_mostly;
41 #endif
42 
43 DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
44 EXPORT_SYMBOL(cpu_hwcaps);
45 static struct arm64_cpu_capabilities const __ro_after_init *cpu_hwcaps_ptrs[ARM64_NCAPS];
46 
47 /* Need also bit for ARM64_CB_PATCH */
48 DECLARE_BITMAP(boot_capabilities, ARM64_NPATCHABLE);
49 
50 /*
51  * Flag to indicate if we have computed the system wide
52  * capabilities based on the boot time active CPUs. This
53  * will be used to determine if a new booting CPU should
54  * go through the verification process to make sure that it
55  * supports the system capabilities, without using a hotplug
56  * notifier.
57  */
58 static bool sys_caps_initialised;
59 
60 static inline void set_sys_caps_initialised(void)
61 {
62 	sys_caps_initialised = true;
63 }
64 
65 static int dump_cpu_hwcaps(struct notifier_block *self, unsigned long v, void *p)
66 {
67 	/* file-wide pr_fmt adds "CPU features: " prefix */
68 	pr_emerg("0x%*pb\n", ARM64_NCAPS, &cpu_hwcaps);
69 	return 0;
70 }
71 
72 static struct notifier_block cpu_hwcaps_notifier = {
73 	.notifier_call = dump_cpu_hwcaps
74 };
75 
76 static int __init register_cpu_hwcaps_dumper(void)
77 {
78 	atomic_notifier_chain_register(&panic_notifier_list,
79 				       &cpu_hwcaps_notifier);
80 	return 0;
81 }
82 __initcall(register_cpu_hwcaps_dumper);
83 
84 DEFINE_STATIC_KEY_ARRAY_FALSE(cpu_hwcap_keys, ARM64_NCAPS);
85 EXPORT_SYMBOL(cpu_hwcap_keys);
86 
87 #define __ARM64_FTR_BITS(SIGNED, VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL) \
88 	{						\
89 		.sign = SIGNED,				\
90 		.visible = VISIBLE,			\
91 		.strict = STRICT,			\
92 		.type = TYPE,				\
93 		.shift = SHIFT,				\
94 		.width = WIDTH,				\
95 		.safe_val = SAFE_VAL,			\
96 	}
97 
98 /* Define a feature with unsigned values */
99 #define ARM64_FTR_BITS(VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL) \
100 	__ARM64_FTR_BITS(FTR_UNSIGNED, VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL)
101 
102 /* Define a feature with a signed value */
103 #define S_ARM64_FTR_BITS(VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL) \
104 	__ARM64_FTR_BITS(FTR_SIGNED, VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL)
105 
106 #define ARM64_FTR_END					\
107 	{						\
108 		.width = 0,				\
109 	}
110 
111 /* meta feature for alternatives */
112 static bool __maybe_unused
113 cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused);
114 
115 static void cpu_enable_cnp(struct arm64_cpu_capabilities const *cap);
116 
117 /*
118  * NOTE: Any changes to the visibility of features should be kept in
119  * sync with the documentation of the CPU feature register ABI.
120  */
121 static const struct arm64_ftr_bits ftr_id_aa64isar0[] = {
122 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_TS_SHIFT, 4, 0),
123 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_FHM_SHIFT, 4, 0),
124 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_DP_SHIFT, 4, 0),
125 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_SM4_SHIFT, 4, 0),
126 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_SM3_SHIFT, 4, 0),
127 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_SHA3_SHIFT, 4, 0),
128 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_RDM_SHIFT, 4, 0),
129 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_ATOMICS_SHIFT, 4, 0),
130 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_CRC32_SHIFT, 4, 0),
131 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_SHA2_SHIFT, 4, 0),
132 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_SHA1_SHIFT, 4, 0),
133 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_AES_SHIFT, 4, 0),
134 	ARM64_FTR_END,
135 };
136 
137 static const struct arm64_ftr_bits ftr_id_aa64isar1[] = {
138 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_SB_SHIFT, 4, 0),
139 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
140 		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_GPI_SHIFT, 4, 0),
141 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
142 		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_GPA_SHIFT, 4, 0),
143 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_LRCPC_SHIFT, 4, 0),
144 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_FCMA_SHIFT, 4, 0),
145 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_JSCVT_SHIFT, 4, 0),
146 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
147 		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_API_SHIFT, 4, 0),
148 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
149 		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_APA_SHIFT, 4, 0),
150 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_DPB_SHIFT, 4, 0),
151 	ARM64_FTR_END,
152 };
153 
154 static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
155 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_CSV3_SHIFT, 4, 0),
156 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_CSV2_SHIFT, 4, 0),
157 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_DIT_SHIFT, 4, 0),
158 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
159 				   FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_SVE_SHIFT, 4, 0),
160 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_RAS_SHIFT, 4, 0),
161 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_GIC_SHIFT, 4, 0),
162 	S_ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_ASIMD_SHIFT, 4, ID_AA64PFR0_ASIMD_NI),
163 	S_ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_FP_SHIFT, 4, ID_AA64PFR0_FP_NI),
164 	/* Linux doesn't care about the EL3 */
165 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL3_SHIFT, 4, 0),
166 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL2_SHIFT, 4, 0),
167 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_SHIFT, 4, ID_AA64PFR0_EL1_64BIT_ONLY),
168 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL0_SHIFT, 4, ID_AA64PFR0_EL0_64BIT_ONLY),
169 	ARM64_FTR_END,
170 };
171 
172 static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = {
173 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_SSBS_SHIFT, 4, ID_AA64PFR1_SSBS_PSTATE_NI),
174 	ARM64_FTR_END,
175 };
176 
177 static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = {
178 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SM4_SHIFT, 4, 0),
179 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SHA3_SHIFT, 4, 0),
180 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_BITPERM_SHIFT, 4, 0),
181 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_AES_SHIFT, 4, 0),
182 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SVEVER_SHIFT, 4, 0),
183 	ARM64_FTR_END,
184 };
185 
186 static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = {
187 	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN4_SHIFT, 4, ID_AA64MMFR0_TGRAN4_NI),
188 	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN64_SHIFT, 4, ID_AA64MMFR0_TGRAN64_NI),
189 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN16_SHIFT, 4, ID_AA64MMFR0_TGRAN16_NI),
190 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_BIGENDEL0_SHIFT, 4, 0),
191 	/* Linux shouldn't care about secure memory */
192 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_SNSMEM_SHIFT, 4, 0),
193 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_BIGENDEL_SHIFT, 4, 0),
194 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_ASID_SHIFT, 4, 0),
195 	/*
196 	 * Differing PARange is fine as long as all peripherals and memory are mapped
197 	 * within the minimum PARange of all CPUs
198 	 */
199 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_PARANGE_SHIFT, 4, 0),
200 	ARM64_FTR_END,
201 };
202 
203 static const struct arm64_ftr_bits ftr_id_aa64mmfr1[] = {
204 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_PAN_SHIFT, 4, 0),
205 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_LOR_SHIFT, 4, 0),
206 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_HPD_SHIFT, 4, 0),
207 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_VHE_SHIFT, 4, 0),
208 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_VMIDBITS_SHIFT, 4, 0),
209 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_HADBS_SHIFT, 4, 0),
210 	ARM64_FTR_END,
211 };
212 
213 static const struct arm64_ftr_bits ftr_id_aa64mmfr2[] = {
214 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_FWB_SHIFT, 4, 0),
215 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_AT_SHIFT, 4, 0),
216 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_LVA_SHIFT, 4, 0),
217 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_IESB_SHIFT, 4, 0),
218 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_LSM_SHIFT, 4, 0),
219 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_UAO_SHIFT, 4, 0),
220 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_CNP_SHIFT, 4, 0),
221 	ARM64_FTR_END,
222 };
223 
224 static const struct arm64_ftr_bits ftr_ctr[] = {
225 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, 31, 1, 1), /* RES1 */
226 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_DIC_SHIFT, 1, 1),
227 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_IDC_SHIFT, 1, 1),
228 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_OR_ZERO_SAFE, CTR_CWG_SHIFT, 4, 0),
229 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_OR_ZERO_SAFE, CTR_ERG_SHIFT, 4, 0),
230 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_DMINLINE_SHIFT, 4, 1),
231 	/*
232 	 * Linux can handle differing I-cache policies. Userspace JITs will
233 	 * make use of *minLine.
234 	 * If we have differing I-cache policies, report it as the weakest - VIPT.
235 	 */
236 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_EXACT, 14, 2, ICACHE_POLICY_VIPT),	/* L1Ip */
237 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_IMINLINE_SHIFT, 4, 0),
238 	ARM64_FTR_END,
239 };
240 
241 struct arm64_ftr_reg arm64_ftr_reg_ctrel0 = {
242 	.name		= "SYS_CTR_EL0",
243 	.ftr_bits	= ftr_ctr
244 };
245 
246 static const struct arm64_ftr_bits ftr_id_mmfr0[] = {
247 	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0xf),	/* InnerShr */
248 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 24, 4, 0),	/* FCSE */
249 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, 20, 4, 0),	/* AuxReg */
250 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 16, 4, 0),	/* TCM */
251 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 12, 4, 0),	/* ShareLvl */
252 	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 8, 4, 0xf),	/* OuterShr */
253 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),	/* PMSA */
254 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0),	/* VMSA */
255 	ARM64_FTR_END,
256 };
257 
258 static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
259 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, 36, 28, 0),
260 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64DFR0_PMSVER_SHIFT, 4, 0),
261 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_CTX_CMPS_SHIFT, 4, 0),
262 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_WRPS_SHIFT, 4, 0),
263 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_BRPS_SHIFT, 4, 0),
264 	/*
265 	 * We can instantiate multiple PMU instances with different levels
266 	 * of support.
267 	 */
268 	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64DFR0_PMUVER_SHIFT, 4, 0),
269 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64DFR0_TRACEVER_SHIFT, 4, 0),
270 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64DFR0_DEBUGVER_SHIFT, 4, 0x6),
271 	ARM64_FTR_END,
272 };
273 
274 static const struct arm64_ftr_bits ftr_mvfr2[] = {
275 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),		/* FPMisc */
276 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0),		/* SIMDMisc */
277 	ARM64_FTR_END,
278 };
279 
280 static const struct arm64_ftr_bits ftr_dczid[] = {
281 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, 4, 1, 1),		/* DZP */
282 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0),	/* BS */
283 	ARM64_FTR_END,
284 };
285 
286 
287 static const struct arm64_ftr_bits ftr_id_isar5[] = {
288 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_RDM_SHIFT, 4, 0),
289 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_CRC32_SHIFT, 4, 0),
290 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SHA2_SHIFT, 4, 0),
291 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SHA1_SHIFT, 4, 0),
292 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_AES_SHIFT, 4, 0),
293 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SEVL_SHIFT, 4, 0),
294 	ARM64_FTR_END,
295 };
296 
297 static const struct arm64_ftr_bits ftr_id_mmfr4[] = {
298 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),	/* ac2 */
299 	ARM64_FTR_END,
300 };
301 
302 static const struct arm64_ftr_bits ftr_id_pfr0[] = {
303 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 12, 4, 0),		/* State3 */
304 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 8, 4, 0),		/* State2 */
305 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),		/* State1 */
306 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0),		/* State0 */
307 	ARM64_FTR_END,
308 };
309 
310 static const struct arm64_ftr_bits ftr_id_dfr0[] = {
311 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
312 	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 24, 4, 0xf),	/* PerfMon */
313 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 20, 4, 0),
314 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 16, 4, 0),
315 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 12, 4, 0),
316 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 8, 4, 0),
317 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),
318 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0),
319 	ARM64_FTR_END,
320 };
321 
322 static const struct arm64_ftr_bits ftr_zcr[] = {
323 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE,
324 		ZCR_ELx_LEN_SHIFT, ZCR_ELx_LEN_SIZE, 0),	/* LEN */
325 	ARM64_FTR_END,
326 };
327 
328 /*
329  * Common ftr bits for a 32bit register with all hidden, strict
330  * attributes, with 4bit feature fields and a default safe value of
331  * 0. Covers the following 32bit registers:
332  * id_isar[0-4], id_mmfr[1-3], id_pfr1, mvfr[0-1]
333  */
334 static const struct arm64_ftr_bits ftr_generic_32bits[] = {
335 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
336 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 24, 4, 0),
337 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 20, 4, 0),
338 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 16, 4, 0),
339 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 12, 4, 0),
340 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 8, 4, 0),
341 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),
342 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0),
343 	ARM64_FTR_END,
344 };
345 
346 /* Table for a single 32bit feature value */
347 static const struct arm64_ftr_bits ftr_single32[] = {
348 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, 0, 32, 0),
349 	ARM64_FTR_END,
350 };
351 
352 static const struct arm64_ftr_bits ftr_raz[] = {
353 	ARM64_FTR_END,
354 };
355 
356 #define ARM64_FTR_REG(id, table) {		\
357 	.sys_id = id,				\
358 	.reg = 	&(struct arm64_ftr_reg){	\
359 		.name = #id,			\
360 		.ftr_bits = &((table)[0]),	\
361 	}}
362 
363 static const struct __ftr_reg_entry {
364 	u32			sys_id;
365 	struct arm64_ftr_reg 	*reg;
366 } arm64_ftr_regs[] = {
367 
368 	/* Op1 = 0, CRn = 0, CRm = 1 */
369 	ARM64_FTR_REG(SYS_ID_PFR0_EL1, ftr_id_pfr0),
370 	ARM64_FTR_REG(SYS_ID_PFR1_EL1, ftr_generic_32bits),
371 	ARM64_FTR_REG(SYS_ID_DFR0_EL1, ftr_id_dfr0),
372 	ARM64_FTR_REG(SYS_ID_MMFR0_EL1, ftr_id_mmfr0),
373 	ARM64_FTR_REG(SYS_ID_MMFR1_EL1, ftr_generic_32bits),
374 	ARM64_FTR_REG(SYS_ID_MMFR2_EL1, ftr_generic_32bits),
375 	ARM64_FTR_REG(SYS_ID_MMFR3_EL1, ftr_generic_32bits),
376 
377 	/* Op1 = 0, CRn = 0, CRm = 2 */
378 	ARM64_FTR_REG(SYS_ID_ISAR0_EL1, ftr_generic_32bits),
379 	ARM64_FTR_REG(SYS_ID_ISAR1_EL1, ftr_generic_32bits),
380 	ARM64_FTR_REG(SYS_ID_ISAR2_EL1, ftr_generic_32bits),
381 	ARM64_FTR_REG(SYS_ID_ISAR3_EL1, ftr_generic_32bits),
382 	ARM64_FTR_REG(SYS_ID_ISAR4_EL1, ftr_generic_32bits),
383 	ARM64_FTR_REG(SYS_ID_ISAR5_EL1, ftr_id_isar5),
384 	ARM64_FTR_REG(SYS_ID_MMFR4_EL1, ftr_id_mmfr4),
385 
386 	/* Op1 = 0, CRn = 0, CRm = 3 */
387 	ARM64_FTR_REG(SYS_MVFR0_EL1, ftr_generic_32bits),
388 	ARM64_FTR_REG(SYS_MVFR1_EL1, ftr_generic_32bits),
389 	ARM64_FTR_REG(SYS_MVFR2_EL1, ftr_mvfr2),
390 
391 	/* Op1 = 0, CRn = 0, CRm = 4 */
392 	ARM64_FTR_REG(SYS_ID_AA64PFR0_EL1, ftr_id_aa64pfr0),
393 	ARM64_FTR_REG(SYS_ID_AA64PFR1_EL1, ftr_id_aa64pfr1),
394 	ARM64_FTR_REG(SYS_ID_AA64ZFR0_EL1, ftr_id_aa64zfr0),
395 
396 	/* Op1 = 0, CRn = 0, CRm = 5 */
397 	ARM64_FTR_REG(SYS_ID_AA64DFR0_EL1, ftr_id_aa64dfr0),
398 	ARM64_FTR_REG(SYS_ID_AA64DFR1_EL1, ftr_raz),
399 
400 	/* Op1 = 0, CRn = 0, CRm = 6 */
401 	ARM64_FTR_REG(SYS_ID_AA64ISAR0_EL1, ftr_id_aa64isar0),
402 	ARM64_FTR_REG(SYS_ID_AA64ISAR1_EL1, ftr_id_aa64isar1),
403 
404 	/* Op1 = 0, CRn = 0, CRm = 7 */
405 	ARM64_FTR_REG(SYS_ID_AA64MMFR0_EL1, ftr_id_aa64mmfr0),
406 	ARM64_FTR_REG(SYS_ID_AA64MMFR1_EL1, ftr_id_aa64mmfr1),
407 	ARM64_FTR_REG(SYS_ID_AA64MMFR2_EL1, ftr_id_aa64mmfr2),
408 
409 	/* Op1 = 0, CRn = 1, CRm = 2 */
410 	ARM64_FTR_REG(SYS_ZCR_EL1, ftr_zcr),
411 
412 	/* Op1 = 3, CRn = 0, CRm = 0 */
413 	{ SYS_CTR_EL0, &arm64_ftr_reg_ctrel0 },
414 	ARM64_FTR_REG(SYS_DCZID_EL0, ftr_dczid),
415 
416 	/* Op1 = 3, CRn = 14, CRm = 0 */
417 	ARM64_FTR_REG(SYS_CNTFRQ_EL0, ftr_single32),
418 };
419 
420 static int search_cmp_ftr_reg(const void *id, const void *regp)
421 {
422 	return (int)(unsigned long)id - (int)((const struct __ftr_reg_entry *)regp)->sys_id;
423 }
424 
425 /*
426  * get_arm64_ftr_reg - Lookup a feature register entry using its
427  * sys_reg() encoding. With the array arm64_ftr_regs sorted in the
428  * ascending order of sys_id , we use binary search to find a matching
429  * entry.
430  *
431  * returns - Upon success,  matching ftr_reg entry for id.
432  *         - NULL on failure. It is upto the caller to decide
433  *	     the impact of a failure.
434  */
435 static struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id)
436 {
437 	const struct __ftr_reg_entry *ret;
438 
439 	ret = bsearch((const void *)(unsigned long)sys_id,
440 			arm64_ftr_regs,
441 			ARRAY_SIZE(arm64_ftr_regs),
442 			sizeof(arm64_ftr_regs[0]),
443 			search_cmp_ftr_reg);
444 	if (ret)
445 		return ret->reg;
446 	return NULL;
447 }
448 
449 static u64 arm64_ftr_set_value(const struct arm64_ftr_bits *ftrp, s64 reg,
450 			       s64 ftr_val)
451 {
452 	u64 mask = arm64_ftr_mask(ftrp);
453 
454 	reg &= ~mask;
455 	reg |= (ftr_val << ftrp->shift) & mask;
456 	return reg;
457 }
458 
459 static s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new,
460 				s64 cur)
461 {
462 	s64 ret = 0;
463 
464 	switch (ftrp->type) {
465 	case FTR_EXACT:
466 		ret = ftrp->safe_val;
467 		break;
468 	case FTR_LOWER_SAFE:
469 		ret = new < cur ? new : cur;
470 		break;
471 	case FTR_HIGHER_OR_ZERO_SAFE:
472 		if (!cur || !new)
473 			break;
474 		/* Fallthrough */
475 	case FTR_HIGHER_SAFE:
476 		ret = new > cur ? new : cur;
477 		break;
478 	default:
479 		BUG();
480 	}
481 
482 	return ret;
483 }
484 
485 static void __init sort_ftr_regs(void)
486 {
487 	int i;
488 
489 	/* Check that the array is sorted so that we can do the binary search */
490 	for (i = 1; i < ARRAY_SIZE(arm64_ftr_regs); i++)
491 		BUG_ON(arm64_ftr_regs[i].sys_id < arm64_ftr_regs[i - 1].sys_id);
492 }
493 
494 /*
495  * Initialise the CPU feature register from Boot CPU values.
496  * Also initiliases the strict_mask for the register.
497  * Any bits that are not covered by an arm64_ftr_bits entry are considered
498  * RES0 for the system-wide value, and must strictly match.
499  */
500 static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new)
501 {
502 	u64 val = 0;
503 	u64 strict_mask = ~0x0ULL;
504 	u64 user_mask = 0;
505 	u64 valid_mask = 0;
506 
507 	const struct arm64_ftr_bits *ftrp;
508 	struct arm64_ftr_reg *reg = get_arm64_ftr_reg(sys_reg);
509 
510 	BUG_ON(!reg);
511 
512 	for (ftrp  = reg->ftr_bits; ftrp->width; ftrp++) {
513 		u64 ftr_mask = arm64_ftr_mask(ftrp);
514 		s64 ftr_new = arm64_ftr_value(ftrp, new);
515 
516 		val = arm64_ftr_set_value(ftrp, val, ftr_new);
517 
518 		valid_mask |= ftr_mask;
519 		if (!ftrp->strict)
520 			strict_mask &= ~ftr_mask;
521 		if (ftrp->visible)
522 			user_mask |= ftr_mask;
523 		else
524 			reg->user_val = arm64_ftr_set_value(ftrp,
525 							    reg->user_val,
526 							    ftrp->safe_val);
527 	}
528 
529 	val &= valid_mask;
530 
531 	reg->sys_val = val;
532 	reg->strict_mask = strict_mask;
533 	reg->user_mask = user_mask;
534 }
535 
536 extern const struct arm64_cpu_capabilities arm64_errata[];
537 static const struct arm64_cpu_capabilities arm64_features[];
538 
539 static void __init
540 init_cpu_hwcaps_indirect_list_from_array(const struct arm64_cpu_capabilities *caps)
541 {
542 	for (; caps->matches; caps++) {
543 		if (WARN(caps->capability >= ARM64_NCAPS,
544 			"Invalid capability %d\n", caps->capability))
545 			continue;
546 		if (WARN(cpu_hwcaps_ptrs[caps->capability],
547 			"Duplicate entry for capability %d\n",
548 			caps->capability))
549 			continue;
550 		cpu_hwcaps_ptrs[caps->capability] = caps;
551 	}
552 }
553 
554 static void __init init_cpu_hwcaps_indirect_list(void)
555 {
556 	init_cpu_hwcaps_indirect_list_from_array(arm64_features);
557 	init_cpu_hwcaps_indirect_list_from_array(arm64_errata);
558 }
559 
560 static void __init setup_boot_cpu_capabilities(void);
561 
562 void __init init_cpu_features(struct cpuinfo_arm64 *info)
563 {
564 	/* Before we start using the tables, make sure it is sorted */
565 	sort_ftr_regs();
566 
567 	init_cpu_ftr_reg(SYS_CTR_EL0, info->reg_ctr);
568 	init_cpu_ftr_reg(SYS_DCZID_EL0, info->reg_dczid);
569 	init_cpu_ftr_reg(SYS_CNTFRQ_EL0, info->reg_cntfrq);
570 	init_cpu_ftr_reg(SYS_ID_AA64DFR0_EL1, info->reg_id_aa64dfr0);
571 	init_cpu_ftr_reg(SYS_ID_AA64DFR1_EL1, info->reg_id_aa64dfr1);
572 	init_cpu_ftr_reg(SYS_ID_AA64ISAR0_EL1, info->reg_id_aa64isar0);
573 	init_cpu_ftr_reg(SYS_ID_AA64ISAR1_EL1, info->reg_id_aa64isar1);
574 	init_cpu_ftr_reg(SYS_ID_AA64MMFR0_EL1, info->reg_id_aa64mmfr0);
575 	init_cpu_ftr_reg(SYS_ID_AA64MMFR1_EL1, info->reg_id_aa64mmfr1);
576 	init_cpu_ftr_reg(SYS_ID_AA64MMFR2_EL1, info->reg_id_aa64mmfr2);
577 	init_cpu_ftr_reg(SYS_ID_AA64PFR0_EL1, info->reg_id_aa64pfr0);
578 	init_cpu_ftr_reg(SYS_ID_AA64PFR1_EL1, info->reg_id_aa64pfr1);
579 	init_cpu_ftr_reg(SYS_ID_AA64ZFR0_EL1, info->reg_id_aa64zfr0);
580 
581 	if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {
582 		init_cpu_ftr_reg(SYS_ID_DFR0_EL1, info->reg_id_dfr0);
583 		init_cpu_ftr_reg(SYS_ID_ISAR0_EL1, info->reg_id_isar0);
584 		init_cpu_ftr_reg(SYS_ID_ISAR1_EL1, info->reg_id_isar1);
585 		init_cpu_ftr_reg(SYS_ID_ISAR2_EL1, info->reg_id_isar2);
586 		init_cpu_ftr_reg(SYS_ID_ISAR3_EL1, info->reg_id_isar3);
587 		init_cpu_ftr_reg(SYS_ID_ISAR4_EL1, info->reg_id_isar4);
588 		init_cpu_ftr_reg(SYS_ID_ISAR5_EL1, info->reg_id_isar5);
589 		init_cpu_ftr_reg(SYS_ID_MMFR0_EL1, info->reg_id_mmfr0);
590 		init_cpu_ftr_reg(SYS_ID_MMFR1_EL1, info->reg_id_mmfr1);
591 		init_cpu_ftr_reg(SYS_ID_MMFR2_EL1, info->reg_id_mmfr2);
592 		init_cpu_ftr_reg(SYS_ID_MMFR3_EL1, info->reg_id_mmfr3);
593 		init_cpu_ftr_reg(SYS_ID_PFR0_EL1, info->reg_id_pfr0);
594 		init_cpu_ftr_reg(SYS_ID_PFR1_EL1, info->reg_id_pfr1);
595 		init_cpu_ftr_reg(SYS_MVFR0_EL1, info->reg_mvfr0);
596 		init_cpu_ftr_reg(SYS_MVFR1_EL1, info->reg_mvfr1);
597 		init_cpu_ftr_reg(SYS_MVFR2_EL1, info->reg_mvfr2);
598 	}
599 
600 	if (id_aa64pfr0_sve(info->reg_id_aa64pfr0)) {
601 		init_cpu_ftr_reg(SYS_ZCR_EL1, info->reg_zcr);
602 		sve_init_vq_map();
603 	}
604 
605 	/*
606 	 * Initialize the indirect array of CPU hwcaps capabilities pointers
607 	 * before we handle the boot CPU below.
608 	 */
609 	init_cpu_hwcaps_indirect_list();
610 
611 	/*
612 	 * Detect and enable early CPU capabilities based on the boot CPU,
613 	 * after we have initialised the CPU feature infrastructure.
614 	 */
615 	setup_boot_cpu_capabilities();
616 }
617 
618 static void update_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 new)
619 {
620 	const struct arm64_ftr_bits *ftrp;
621 
622 	for (ftrp = reg->ftr_bits; ftrp->width; ftrp++) {
623 		s64 ftr_cur = arm64_ftr_value(ftrp, reg->sys_val);
624 		s64 ftr_new = arm64_ftr_value(ftrp, new);
625 
626 		if (ftr_cur == ftr_new)
627 			continue;
628 		/* Find a safe value */
629 		ftr_new = arm64_ftr_safe_value(ftrp, ftr_new, ftr_cur);
630 		reg->sys_val = arm64_ftr_set_value(ftrp, reg->sys_val, ftr_new);
631 	}
632 
633 }
634 
635 static int check_update_ftr_reg(u32 sys_id, int cpu, u64 val, u64 boot)
636 {
637 	struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id);
638 
639 	BUG_ON(!regp);
640 	update_cpu_ftr_reg(regp, val);
641 	if ((boot & regp->strict_mask) == (val & regp->strict_mask))
642 		return 0;
643 	pr_warn("SANITY CHECK: Unexpected variation in %s. Boot CPU: %#016llx, CPU%d: %#016llx\n",
644 			regp->name, boot, cpu, val);
645 	return 1;
646 }
647 
648 /*
649  * Update system wide CPU feature registers with the values from a
650  * non-boot CPU. Also performs SANITY checks to make sure that there
651  * aren't any insane variations from that of the boot CPU.
652  */
653 void update_cpu_features(int cpu,
654 			 struct cpuinfo_arm64 *info,
655 			 struct cpuinfo_arm64 *boot)
656 {
657 	int taint = 0;
658 
659 	/*
660 	 * The kernel can handle differing I-cache policies, but otherwise
661 	 * caches should look identical. Userspace JITs will make use of
662 	 * *minLine.
663 	 */
664 	taint |= check_update_ftr_reg(SYS_CTR_EL0, cpu,
665 				      info->reg_ctr, boot->reg_ctr);
666 
667 	/*
668 	 * Userspace may perform DC ZVA instructions. Mismatched block sizes
669 	 * could result in too much or too little memory being zeroed if a
670 	 * process is preempted and migrated between CPUs.
671 	 */
672 	taint |= check_update_ftr_reg(SYS_DCZID_EL0, cpu,
673 				      info->reg_dczid, boot->reg_dczid);
674 
675 	/* If different, timekeeping will be broken (especially with KVM) */
676 	taint |= check_update_ftr_reg(SYS_CNTFRQ_EL0, cpu,
677 				      info->reg_cntfrq, boot->reg_cntfrq);
678 
679 	/*
680 	 * The kernel uses self-hosted debug features and expects CPUs to
681 	 * support identical debug features. We presently need CTX_CMPs, WRPs,
682 	 * and BRPs to be identical.
683 	 * ID_AA64DFR1 is currently RES0.
684 	 */
685 	taint |= check_update_ftr_reg(SYS_ID_AA64DFR0_EL1, cpu,
686 				      info->reg_id_aa64dfr0, boot->reg_id_aa64dfr0);
687 	taint |= check_update_ftr_reg(SYS_ID_AA64DFR1_EL1, cpu,
688 				      info->reg_id_aa64dfr1, boot->reg_id_aa64dfr1);
689 	/*
690 	 * Even in big.LITTLE, processors should be identical instruction-set
691 	 * wise.
692 	 */
693 	taint |= check_update_ftr_reg(SYS_ID_AA64ISAR0_EL1, cpu,
694 				      info->reg_id_aa64isar0, boot->reg_id_aa64isar0);
695 	taint |= check_update_ftr_reg(SYS_ID_AA64ISAR1_EL1, cpu,
696 				      info->reg_id_aa64isar1, boot->reg_id_aa64isar1);
697 
698 	/*
699 	 * Differing PARange support is fine as long as all peripherals and
700 	 * memory are mapped within the minimum PARange of all CPUs.
701 	 * Linux should not care about secure memory.
702 	 */
703 	taint |= check_update_ftr_reg(SYS_ID_AA64MMFR0_EL1, cpu,
704 				      info->reg_id_aa64mmfr0, boot->reg_id_aa64mmfr0);
705 	taint |= check_update_ftr_reg(SYS_ID_AA64MMFR1_EL1, cpu,
706 				      info->reg_id_aa64mmfr1, boot->reg_id_aa64mmfr1);
707 	taint |= check_update_ftr_reg(SYS_ID_AA64MMFR2_EL1, cpu,
708 				      info->reg_id_aa64mmfr2, boot->reg_id_aa64mmfr2);
709 
710 	/*
711 	 * EL3 is not our concern.
712 	 */
713 	taint |= check_update_ftr_reg(SYS_ID_AA64PFR0_EL1, cpu,
714 				      info->reg_id_aa64pfr0, boot->reg_id_aa64pfr0);
715 	taint |= check_update_ftr_reg(SYS_ID_AA64PFR1_EL1, cpu,
716 				      info->reg_id_aa64pfr1, boot->reg_id_aa64pfr1);
717 
718 	taint |= check_update_ftr_reg(SYS_ID_AA64ZFR0_EL1, cpu,
719 				      info->reg_id_aa64zfr0, boot->reg_id_aa64zfr0);
720 
721 	/*
722 	 * If we have AArch32, we care about 32-bit features for compat.
723 	 * If the system doesn't support AArch32, don't update them.
724 	 */
725 	if (id_aa64pfr0_32bit_el0(read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1)) &&
726 		id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {
727 
728 		taint |= check_update_ftr_reg(SYS_ID_DFR0_EL1, cpu,
729 					info->reg_id_dfr0, boot->reg_id_dfr0);
730 		taint |= check_update_ftr_reg(SYS_ID_ISAR0_EL1, cpu,
731 					info->reg_id_isar0, boot->reg_id_isar0);
732 		taint |= check_update_ftr_reg(SYS_ID_ISAR1_EL1, cpu,
733 					info->reg_id_isar1, boot->reg_id_isar1);
734 		taint |= check_update_ftr_reg(SYS_ID_ISAR2_EL1, cpu,
735 					info->reg_id_isar2, boot->reg_id_isar2);
736 		taint |= check_update_ftr_reg(SYS_ID_ISAR3_EL1, cpu,
737 					info->reg_id_isar3, boot->reg_id_isar3);
738 		taint |= check_update_ftr_reg(SYS_ID_ISAR4_EL1, cpu,
739 					info->reg_id_isar4, boot->reg_id_isar4);
740 		taint |= check_update_ftr_reg(SYS_ID_ISAR5_EL1, cpu,
741 					info->reg_id_isar5, boot->reg_id_isar5);
742 
743 		/*
744 		 * Regardless of the value of the AuxReg field, the AIFSR, ADFSR, and
745 		 * ACTLR formats could differ across CPUs and therefore would have to
746 		 * be trapped for virtualization anyway.
747 		 */
748 		taint |= check_update_ftr_reg(SYS_ID_MMFR0_EL1, cpu,
749 					info->reg_id_mmfr0, boot->reg_id_mmfr0);
750 		taint |= check_update_ftr_reg(SYS_ID_MMFR1_EL1, cpu,
751 					info->reg_id_mmfr1, boot->reg_id_mmfr1);
752 		taint |= check_update_ftr_reg(SYS_ID_MMFR2_EL1, cpu,
753 					info->reg_id_mmfr2, boot->reg_id_mmfr2);
754 		taint |= check_update_ftr_reg(SYS_ID_MMFR3_EL1, cpu,
755 					info->reg_id_mmfr3, boot->reg_id_mmfr3);
756 		taint |= check_update_ftr_reg(SYS_ID_PFR0_EL1, cpu,
757 					info->reg_id_pfr0, boot->reg_id_pfr0);
758 		taint |= check_update_ftr_reg(SYS_ID_PFR1_EL1, cpu,
759 					info->reg_id_pfr1, boot->reg_id_pfr1);
760 		taint |= check_update_ftr_reg(SYS_MVFR0_EL1, cpu,
761 					info->reg_mvfr0, boot->reg_mvfr0);
762 		taint |= check_update_ftr_reg(SYS_MVFR1_EL1, cpu,
763 					info->reg_mvfr1, boot->reg_mvfr1);
764 		taint |= check_update_ftr_reg(SYS_MVFR2_EL1, cpu,
765 					info->reg_mvfr2, boot->reg_mvfr2);
766 	}
767 
768 	if (id_aa64pfr0_sve(info->reg_id_aa64pfr0)) {
769 		taint |= check_update_ftr_reg(SYS_ZCR_EL1, cpu,
770 					info->reg_zcr, boot->reg_zcr);
771 
772 		/* Probe vector lengths, unless we already gave up on SVE */
773 		if (id_aa64pfr0_sve(read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1)) &&
774 		    !sys_caps_initialised)
775 			sve_update_vq_map();
776 	}
777 
778 	/*
779 	 * Mismatched CPU features are a recipe for disaster. Don't even
780 	 * pretend to support them.
781 	 */
782 	if (taint) {
783 		pr_warn_once("Unsupported CPU feature variation detected.\n");
784 		add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
785 	}
786 }
787 
788 u64 read_sanitised_ftr_reg(u32 id)
789 {
790 	struct arm64_ftr_reg *regp = get_arm64_ftr_reg(id);
791 
792 	/* We shouldn't get a request for an unsupported register */
793 	BUG_ON(!regp);
794 	return regp->sys_val;
795 }
796 
797 #define read_sysreg_case(r)	\
798 	case r:		return read_sysreg_s(r)
799 
800 /*
801  * __read_sysreg_by_encoding() - Used by a STARTING cpu before cpuinfo is populated.
802  * Read the system register on the current CPU
803  */
804 static u64 __read_sysreg_by_encoding(u32 sys_id)
805 {
806 	switch (sys_id) {
807 	read_sysreg_case(SYS_ID_PFR0_EL1);
808 	read_sysreg_case(SYS_ID_PFR1_EL1);
809 	read_sysreg_case(SYS_ID_DFR0_EL1);
810 	read_sysreg_case(SYS_ID_MMFR0_EL1);
811 	read_sysreg_case(SYS_ID_MMFR1_EL1);
812 	read_sysreg_case(SYS_ID_MMFR2_EL1);
813 	read_sysreg_case(SYS_ID_MMFR3_EL1);
814 	read_sysreg_case(SYS_ID_ISAR0_EL1);
815 	read_sysreg_case(SYS_ID_ISAR1_EL1);
816 	read_sysreg_case(SYS_ID_ISAR2_EL1);
817 	read_sysreg_case(SYS_ID_ISAR3_EL1);
818 	read_sysreg_case(SYS_ID_ISAR4_EL1);
819 	read_sysreg_case(SYS_ID_ISAR5_EL1);
820 	read_sysreg_case(SYS_MVFR0_EL1);
821 	read_sysreg_case(SYS_MVFR1_EL1);
822 	read_sysreg_case(SYS_MVFR2_EL1);
823 
824 	read_sysreg_case(SYS_ID_AA64PFR0_EL1);
825 	read_sysreg_case(SYS_ID_AA64PFR1_EL1);
826 	read_sysreg_case(SYS_ID_AA64ZFR0_EL1);
827 	read_sysreg_case(SYS_ID_AA64DFR0_EL1);
828 	read_sysreg_case(SYS_ID_AA64DFR1_EL1);
829 	read_sysreg_case(SYS_ID_AA64MMFR0_EL1);
830 	read_sysreg_case(SYS_ID_AA64MMFR1_EL1);
831 	read_sysreg_case(SYS_ID_AA64MMFR2_EL1);
832 	read_sysreg_case(SYS_ID_AA64ISAR0_EL1);
833 	read_sysreg_case(SYS_ID_AA64ISAR1_EL1);
834 
835 	read_sysreg_case(SYS_CNTFRQ_EL0);
836 	read_sysreg_case(SYS_CTR_EL0);
837 	read_sysreg_case(SYS_DCZID_EL0);
838 
839 	default:
840 		BUG();
841 		return 0;
842 	}
843 }
844 
845 #include <linux/irqchip/arm-gic-v3.h>
846 
847 static bool
848 feature_matches(u64 reg, const struct arm64_cpu_capabilities *entry)
849 {
850 	int val = cpuid_feature_extract_field(reg, entry->field_pos, entry->sign);
851 
852 	return val >= entry->min_field_value;
853 }
854 
855 static bool
856 has_cpuid_feature(const struct arm64_cpu_capabilities *entry, int scope)
857 {
858 	u64 val;
859 
860 	WARN_ON(scope == SCOPE_LOCAL_CPU && preemptible());
861 	if (scope == SCOPE_SYSTEM)
862 		val = read_sanitised_ftr_reg(entry->sys_reg);
863 	else
864 		val = __read_sysreg_by_encoding(entry->sys_reg);
865 
866 	return feature_matches(val, entry);
867 }
868 
869 static bool has_useable_gicv3_cpuif(const struct arm64_cpu_capabilities *entry, int scope)
870 {
871 	bool has_sre;
872 
873 	if (!has_cpuid_feature(entry, scope))
874 		return false;
875 
876 	has_sre = gic_enable_sre();
877 	if (!has_sre)
878 		pr_warn_once("%s present but disabled by higher exception level\n",
879 			     entry->desc);
880 
881 	return has_sre;
882 }
883 
884 static bool has_no_hw_prefetch(const struct arm64_cpu_capabilities *entry, int __unused)
885 {
886 	u32 midr = read_cpuid_id();
887 
888 	/* Cavium ThunderX pass 1.x and 2.x */
889 	return MIDR_IS_CPU_MODEL_RANGE(midr, MIDR_THUNDERX,
890 		MIDR_CPU_VAR_REV(0, 0),
891 		MIDR_CPU_VAR_REV(1, MIDR_REVISION_MASK));
892 }
893 
894 static bool has_no_fpsimd(const struct arm64_cpu_capabilities *entry, int __unused)
895 {
896 	u64 pfr0 = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);
897 
898 	return cpuid_feature_extract_signed_field(pfr0,
899 					ID_AA64PFR0_FP_SHIFT) < 0;
900 }
901 
902 static bool has_cache_idc(const struct arm64_cpu_capabilities *entry,
903 			  int scope)
904 {
905 	u64 ctr;
906 
907 	if (scope == SCOPE_SYSTEM)
908 		ctr = arm64_ftr_reg_ctrel0.sys_val;
909 	else
910 		ctr = read_cpuid_effective_cachetype();
911 
912 	return ctr & BIT(CTR_IDC_SHIFT);
913 }
914 
915 static void cpu_emulate_effective_ctr(const struct arm64_cpu_capabilities *__unused)
916 {
917 	/*
918 	 * If the CPU exposes raw CTR_EL0.IDC = 0, while effectively
919 	 * CTR_EL0.IDC = 1 (from CLIDR values), we need to trap accesses
920 	 * to the CTR_EL0 on this CPU and emulate it with the real/safe
921 	 * value.
922 	 */
923 	if (!(read_cpuid_cachetype() & BIT(CTR_IDC_SHIFT)))
924 		sysreg_clear_set(sctlr_el1, SCTLR_EL1_UCT, 0);
925 }
926 
927 static bool has_cache_dic(const struct arm64_cpu_capabilities *entry,
928 			  int scope)
929 {
930 	u64 ctr;
931 
932 	if (scope == SCOPE_SYSTEM)
933 		ctr = arm64_ftr_reg_ctrel0.sys_val;
934 	else
935 		ctr = read_cpuid_cachetype();
936 
937 	return ctr & BIT(CTR_DIC_SHIFT);
938 }
939 
940 static bool __maybe_unused
941 has_useable_cnp(const struct arm64_cpu_capabilities *entry, int scope)
942 {
943 	/*
944 	 * Kdump isn't guaranteed to power-off all secondary CPUs, CNP
945 	 * may share TLB entries with a CPU stuck in the crashed
946 	 * kernel.
947 	 */
948 	 if (is_kdump_kernel())
949 		return false;
950 
951 	return has_cpuid_feature(entry, scope);
952 }
953 
954 static bool __meltdown_safe = true;
955 static int __kpti_forced; /* 0: not forced, >0: forced on, <0: forced off */
956 
957 static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
958 				int scope)
959 {
960 	/* List of CPUs that are not vulnerable and don't need KPTI */
961 	static const struct midr_range kpti_safe_list[] = {
962 		MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2),
963 		MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
964 		MIDR_ALL_VERSIONS(MIDR_CORTEX_A35),
965 		MIDR_ALL_VERSIONS(MIDR_CORTEX_A53),
966 		MIDR_ALL_VERSIONS(MIDR_CORTEX_A55),
967 		MIDR_ALL_VERSIONS(MIDR_CORTEX_A57),
968 		MIDR_ALL_VERSIONS(MIDR_CORTEX_A72),
969 		MIDR_ALL_VERSIONS(MIDR_CORTEX_A73),
970 		MIDR_ALL_VERSIONS(MIDR_HISI_TSV110),
971 		{ /* sentinel */ }
972 	};
973 	char const *str = "kpti command line option";
974 	bool meltdown_safe;
975 
976 	meltdown_safe = is_midr_in_range_list(read_cpuid_id(), kpti_safe_list);
977 
978 	/* Defer to CPU feature registers */
979 	if (has_cpuid_feature(entry, scope))
980 		meltdown_safe = true;
981 
982 	if (!meltdown_safe)
983 		__meltdown_safe = false;
984 
985 	/*
986 	 * For reasons that aren't entirely clear, enabling KPTI on Cavium
987 	 * ThunderX leads to apparent I-cache corruption of kernel text, which
988 	 * ends as well as you might imagine. Don't even try.
989 	 */
990 	if (cpus_have_const_cap(ARM64_WORKAROUND_CAVIUM_27456)) {
991 		str = "ARM64_WORKAROUND_CAVIUM_27456";
992 		__kpti_forced = -1;
993 	}
994 
995 	/* Useful for KASLR robustness */
996 	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_offset() > 0) {
997 		if (!__kpti_forced) {
998 			str = "KASLR";
999 			__kpti_forced = 1;
1000 		}
1001 	}
1002 
1003 	if (cpu_mitigations_off() && !__kpti_forced) {
1004 		str = "mitigations=off";
1005 		__kpti_forced = -1;
1006 	}
1007 
1008 	if (!IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0)) {
1009 		pr_info_once("kernel page table isolation disabled by kernel configuration\n");
1010 		return false;
1011 	}
1012 
1013 	/* Forced? */
1014 	if (__kpti_forced) {
1015 		pr_info_once("kernel page table isolation forced %s by %s\n",
1016 			     __kpti_forced > 0 ? "ON" : "OFF", str);
1017 		return __kpti_forced > 0;
1018 	}
1019 
1020 	return !meltdown_safe;
1021 }
1022 
1023 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
1024 static void
1025 kpti_install_ng_mappings(const struct arm64_cpu_capabilities *__unused)
1026 {
1027 	typedef void (kpti_remap_fn)(int, int, phys_addr_t);
1028 	extern kpti_remap_fn idmap_kpti_install_ng_mappings;
1029 	kpti_remap_fn *remap_fn;
1030 
1031 	static bool kpti_applied = false;
1032 	int cpu = smp_processor_id();
1033 
1034 	/*
1035 	 * We don't need to rewrite the page-tables if either we've done
1036 	 * it already or we have KASLR enabled and therefore have not
1037 	 * created any global mappings at all.
1038 	 */
1039 	if (kpti_applied || kaslr_offset() > 0)
1040 		return;
1041 
1042 	remap_fn = (void *)__pa_symbol(idmap_kpti_install_ng_mappings);
1043 
1044 	cpu_install_idmap();
1045 	remap_fn(cpu, num_online_cpus(), __pa_symbol(swapper_pg_dir));
1046 	cpu_uninstall_idmap();
1047 
1048 	if (!cpu)
1049 		kpti_applied = true;
1050 
1051 	return;
1052 }
1053 #else
1054 static void
1055 kpti_install_ng_mappings(const struct arm64_cpu_capabilities *__unused)
1056 {
1057 }
1058 #endif	/* CONFIG_UNMAP_KERNEL_AT_EL0 */
1059 
1060 static int __init parse_kpti(char *str)
1061 {
1062 	bool enabled;
1063 	int ret = strtobool(str, &enabled);
1064 
1065 	if (ret)
1066 		return ret;
1067 
1068 	__kpti_forced = enabled ? 1 : -1;
1069 	return 0;
1070 }
1071 early_param("kpti", parse_kpti);
1072 
1073 #ifdef CONFIG_ARM64_HW_AFDBM
1074 static inline void __cpu_enable_hw_dbm(void)
1075 {
1076 	u64 tcr = read_sysreg(tcr_el1) | TCR_HD;
1077 
1078 	write_sysreg(tcr, tcr_el1);
1079 	isb();
1080 }
1081 
1082 static bool cpu_has_broken_dbm(void)
1083 {
1084 	/* List of CPUs which have broken DBM support. */
1085 	static const struct midr_range cpus[] = {
1086 #ifdef CONFIG_ARM64_ERRATUM_1024718
1087 		MIDR_RANGE(MIDR_CORTEX_A55, 0, 0, 1, 0),  // A55 r0p0 -r1p0
1088 #endif
1089 		{},
1090 	};
1091 
1092 	return is_midr_in_range_list(read_cpuid_id(), cpus);
1093 }
1094 
1095 static bool cpu_can_use_dbm(const struct arm64_cpu_capabilities *cap)
1096 {
1097 	return has_cpuid_feature(cap, SCOPE_LOCAL_CPU) &&
1098 	       !cpu_has_broken_dbm();
1099 }
1100 
1101 static void cpu_enable_hw_dbm(struct arm64_cpu_capabilities const *cap)
1102 {
1103 	if (cpu_can_use_dbm(cap))
1104 		__cpu_enable_hw_dbm();
1105 }
1106 
1107 static bool has_hw_dbm(const struct arm64_cpu_capabilities *cap,
1108 		       int __unused)
1109 {
1110 	static bool detected = false;
1111 	/*
1112 	 * DBM is a non-conflicting feature. i.e, the kernel can safely
1113 	 * run a mix of CPUs with and without the feature. So, we
1114 	 * unconditionally enable the capability to allow any late CPU
1115 	 * to use the feature. We only enable the control bits on the
1116 	 * CPU, if it actually supports.
1117 	 *
1118 	 * We have to make sure we print the "feature" detection only
1119 	 * when at least one CPU actually uses it. So check if this CPU
1120 	 * can actually use it and print the message exactly once.
1121 	 *
1122 	 * This is safe as all CPUs (including secondary CPUs - due to the
1123 	 * LOCAL_CPU scope - and the hotplugged CPUs - via verification)
1124 	 * goes through the "matches" check exactly once. Also if a CPU
1125 	 * matches the criteria, it is guaranteed that the CPU will turn
1126 	 * the DBM on, as the capability is unconditionally enabled.
1127 	 */
1128 	if (!detected && cpu_can_use_dbm(cap)) {
1129 		detected = true;
1130 		pr_info("detected: Hardware dirty bit management\n");
1131 	}
1132 
1133 	return true;
1134 }
1135 
1136 #endif
1137 
1138 #ifdef CONFIG_ARM64_VHE
1139 static bool runs_at_el2(const struct arm64_cpu_capabilities *entry, int __unused)
1140 {
1141 	return is_kernel_in_hyp_mode();
1142 }
1143 
1144 static void cpu_copy_el2regs(const struct arm64_cpu_capabilities *__unused)
1145 {
1146 	/*
1147 	 * Copy register values that aren't redirected by hardware.
1148 	 *
1149 	 * Before code patching, we only set tpidr_el1, all CPUs need to copy
1150 	 * this value to tpidr_el2 before we patch the code. Once we've done
1151 	 * that, freshly-onlined CPUs will set tpidr_el2, so we don't need to
1152 	 * do anything here.
1153 	 */
1154 	if (!alternative_is_applied(ARM64_HAS_VIRT_HOST_EXTN))
1155 		write_sysreg(read_sysreg(tpidr_el1), tpidr_el2);
1156 }
1157 #endif
1158 
1159 static void cpu_has_fwb(const struct arm64_cpu_capabilities *__unused)
1160 {
1161 	u64 val = read_sysreg_s(SYS_CLIDR_EL1);
1162 
1163 	/* Check that CLIDR_EL1.LOU{U,IS} are both 0 */
1164 	WARN_ON(val & (7 << 27 | 7 << 21));
1165 }
1166 
1167 #ifdef CONFIG_ARM64_SSBD
1168 static int ssbs_emulation_handler(struct pt_regs *regs, u32 instr)
1169 {
1170 	if (user_mode(regs))
1171 		return 1;
1172 
1173 	if (instr & BIT(PSTATE_Imm_shift))
1174 		regs->pstate |= PSR_SSBS_BIT;
1175 	else
1176 		regs->pstate &= ~PSR_SSBS_BIT;
1177 
1178 	arm64_skip_faulting_instruction(regs, 4);
1179 	return 0;
1180 }
1181 
1182 static struct undef_hook ssbs_emulation_hook = {
1183 	.instr_mask	= ~(1U << PSTATE_Imm_shift),
1184 	.instr_val	= 0xd500401f | PSTATE_SSBS,
1185 	.fn		= ssbs_emulation_handler,
1186 };
1187 
1188 static void cpu_enable_ssbs(const struct arm64_cpu_capabilities *__unused)
1189 {
1190 	static bool undef_hook_registered = false;
1191 	static DEFINE_RAW_SPINLOCK(hook_lock);
1192 
1193 	raw_spin_lock(&hook_lock);
1194 	if (!undef_hook_registered) {
1195 		register_undef_hook(&ssbs_emulation_hook);
1196 		undef_hook_registered = true;
1197 	}
1198 	raw_spin_unlock(&hook_lock);
1199 
1200 	if (arm64_get_ssbd_state() == ARM64_SSBD_FORCE_DISABLE) {
1201 		sysreg_clear_set(sctlr_el1, 0, SCTLR_ELx_DSSBS);
1202 		arm64_set_ssbd_mitigation(false);
1203 	} else {
1204 		arm64_set_ssbd_mitigation(true);
1205 	}
1206 }
1207 #endif /* CONFIG_ARM64_SSBD */
1208 
1209 #ifdef CONFIG_ARM64_PAN
1210 static void cpu_enable_pan(const struct arm64_cpu_capabilities *__unused)
1211 {
1212 	/*
1213 	 * We modify PSTATE. This won't work from irq context as the PSTATE
1214 	 * is discarded once we return from the exception.
1215 	 */
1216 	WARN_ON_ONCE(in_interrupt());
1217 
1218 	sysreg_clear_set(sctlr_el1, SCTLR_EL1_SPAN, 0);
1219 	asm(SET_PSTATE_PAN(1));
1220 }
1221 #endif /* CONFIG_ARM64_PAN */
1222 
1223 #ifdef CONFIG_ARM64_RAS_EXTN
1224 static void cpu_clear_disr(const struct arm64_cpu_capabilities *__unused)
1225 {
1226 	/* Firmware may have left a deferred SError in this register. */
1227 	write_sysreg_s(0, SYS_DISR_EL1);
1228 }
1229 #endif /* CONFIG_ARM64_RAS_EXTN */
1230 
1231 #ifdef CONFIG_ARM64_PTR_AUTH
1232 static void cpu_enable_address_auth(struct arm64_cpu_capabilities const *cap)
1233 {
1234 	sysreg_clear_set(sctlr_el1, 0, SCTLR_ELx_ENIA | SCTLR_ELx_ENIB |
1235 				       SCTLR_ELx_ENDA | SCTLR_ELx_ENDB);
1236 }
1237 #endif /* CONFIG_ARM64_PTR_AUTH */
1238 
1239 #ifdef CONFIG_ARM64_PSEUDO_NMI
1240 static bool enable_pseudo_nmi;
1241 
1242 static int __init early_enable_pseudo_nmi(char *p)
1243 {
1244 	return strtobool(p, &enable_pseudo_nmi);
1245 }
1246 early_param("irqchip.gicv3_pseudo_nmi", early_enable_pseudo_nmi);
1247 
1248 static bool can_use_gic_priorities(const struct arm64_cpu_capabilities *entry,
1249 				   int scope)
1250 {
1251 	return enable_pseudo_nmi && has_useable_gicv3_cpuif(entry, scope);
1252 }
1253 #endif
1254 
1255 static const struct arm64_cpu_capabilities arm64_features[] = {
1256 	{
1257 		.desc = "GIC system register CPU interface",
1258 		.capability = ARM64_HAS_SYSREG_GIC_CPUIF,
1259 		.type = ARM64_CPUCAP_STRICT_BOOT_CPU_FEATURE,
1260 		.matches = has_useable_gicv3_cpuif,
1261 		.sys_reg = SYS_ID_AA64PFR0_EL1,
1262 		.field_pos = ID_AA64PFR0_GIC_SHIFT,
1263 		.sign = FTR_UNSIGNED,
1264 		.min_field_value = 1,
1265 	},
1266 #ifdef CONFIG_ARM64_PAN
1267 	{
1268 		.desc = "Privileged Access Never",
1269 		.capability = ARM64_HAS_PAN,
1270 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1271 		.matches = has_cpuid_feature,
1272 		.sys_reg = SYS_ID_AA64MMFR1_EL1,
1273 		.field_pos = ID_AA64MMFR1_PAN_SHIFT,
1274 		.sign = FTR_UNSIGNED,
1275 		.min_field_value = 1,
1276 		.cpu_enable = cpu_enable_pan,
1277 	},
1278 #endif /* CONFIG_ARM64_PAN */
1279 #if defined(CONFIG_AS_LSE) && defined(CONFIG_ARM64_LSE_ATOMICS)
1280 	{
1281 		.desc = "LSE atomic instructions",
1282 		.capability = ARM64_HAS_LSE_ATOMICS,
1283 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1284 		.matches = has_cpuid_feature,
1285 		.sys_reg = SYS_ID_AA64ISAR0_EL1,
1286 		.field_pos = ID_AA64ISAR0_ATOMICS_SHIFT,
1287 		.sign = FTR_UNSIGNED,
1288 		.min_field_value = 2,
1289 	},
1290 #endif /* CONFIG_AS_LSE && CONFIG_ARM64_LSE_ATOMICS */
1291 	{
1292 		.desc = "Software prefetching using PRFM",
1293 		.capability = ARM64_HAS_NO_HW_PREFETCH,
1294 		.type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE,
1295 		.matches = has_no_hw_prefetch,
1296 	},
1297 #ifdef CONFIG_ARM64_UAO
1298 	{
1299 		.desc = "User Access Override",
1300 		.capability = ARM64_HAS_UAO,
1301 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1302 		.matches = has_cpuid_feature,
1303 		.sys_reg = SYS_ID_AA64MMFR2_EL1,
1304 		.field_pos = ID_AA64MMFR2_UAO_SHIFT,
1305 		.min_field_value = 1,
1306 		/*
1307 		 * We rely on stop_machine() calling uao_thread_switch() to set
1308 		 * UAO immediately after patching.
1309 		 */
1310 	},
1311 #endif /* CONFIG_ARM64_UAO */
1312 #ifdef CONFIG_ARM64_PAN
1313 	{
1314 		.capability = ARM64_ALT_PAN_NOT_UAO,
1315 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1316 		.matches = cpufeature_pan_not_uao,
1317 	},
1318 #endif /* CONFIG_ARM64_PAN */
1319 #ifdef CONFIG_ARM64_VHE
1320 	{
1321 		.desc = "Virtualization Host Extensions",
1322 		.capability = ARM64_HAS_VIRT_HOST_EXTN,
1323 		.type = ARM64_CPUCAP_STRICT_BOOT_CPU_FEATURE,
1324 		.matches = runs_at_el2,
1325 		.cpu_enable = cpu_copy_el2regs,
1326 	},
1327 #endif	/* CONFIG_ARM64_VHE */
1328 	{
1329 		.desc = "32-bit EL0 Support",
1330 		.capability = ARM64_HAS_32BIT_EL0,
1331 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1332 		.matches = has_cpuid_feature,
1333 		.sys_reg = SYS_ID_AA64PFR0_EL1,
1334 		.sign = FTR_UNSIGNED,
1335 		.field_pos = ID_AA64PFR0_EL0_SHIFT,
1336 		.min_field_value = ID_AA64PFR0_EL0_32BIT_64BIT,
1337 	},
1338 	{
1339 		.desc = "Kernel page table isolation (KPTI)",
1340 		.capability = ARM64_UNMAP_KERNEL_AT_EL0,
1341 		.type = ARM64_CPUCAP_BOOT_RESTRICTED_CPU_LOCAL_FEATURE,
1342 		/*
1343 		 * The ID feature fields below are used to indicate that
1344 		 * the CPU doesn't need KPTI. See unmap_kernel_at_el0 for
1345 		 * more details.
1346 		 */
1347 		.sys_reg = SYS_ID_AA64PFR0_EL1,
1348 		.field_pos = ID_AA64PFR0_CSV3_SHIFT,
1349 		.min_field_value = 1,
1350 		.matches = unmap_kernel_at_el0,
1351 		.cpu_enable = kpti_install_ng_mappings,
1352 	},
1353 	{
1354 		/* FP/SIMD is not implemented */
1355 		.capability = ARM64_HAS_NO_FPSIMD,
1356 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1357 		.min_field_value = 0,
1358 		.matches = has_no_fpsimd,
1359 	},
1360 #ifdef CONFIG_ARM64_PMEM
1361 	{
1362 		.desc = "Data cache clean to Point of Persistence",
1363 		.capability = ARM64_HAS_DCPOP,
1364 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1365 		.matches = has_cpuid_feature,
1366 		.sys_reg = SYS_ID_AA64ISAR1_EL1,
1367 		.field_pos = ID_AA64ISAR1_DPB_SHIFT,
1368 		.min_field_value = 1,
1369 	},
1370 	{
1371 		.desc = "Data cache clean to Point of Deep Persistence",
1372 		.capability = ARM64_HAS_DCPODP,
1373 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1374 		.matches = has_cpuid_feature,
1375 		.sys_reg = SYS_ID_AA64ISAR1_EL1,
1376 		.sign = FTR_UNSIGNED,
1377 		.field_pos = ID_AA64ISAR1_DPB_SHIFT,
1378 		.min_field_value = 2,
1379 	},
1380 #endif
1381 #ifdef CONFIG_ARM64_SVE
1382 	{
1383 		.desc = "Scalable Vector Extension",
1384 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1385 		.capability = ARM64_SVE,
1386 		.sys_reg = SYS_ID_AA64PFR0_EL1,
1387 		.sign = FTR_UNSIGNED,
1388 		.field_pos = ID_AA64PFR0_SVE_SHIFT,
1389 		.min_field_value = ID_AA64PFR0_SVE,
1390 		.matches = has_cpuid_feature,
1391 		.cpu_enable = sve_kernel_enable,
1392 	},
1393 #endif /* CONFIG_ARM64_SVE */
1394 #ifdef CONFIG_ARM64_RAS_EXTN
1395 	{
1396 		.desc = "RAS Extension Support",
1397 		.capability = ARM64_HAS_RAS_EXTN,
1398 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1399 		.matches = has_cpuid_feature,
1400 		.sys_reg = SYS_ID_AA64PFR0_EL1,
1401 		.sign = FTR_UNSIGNED,
1402 		.field_pos = ID_AA64PFR0_RAS_SHIFT,
1403 		.min_field_value = ID_AA64PFR0_RAS_V1,
1404 		.cpu_enable = cpu_clear_disr,
1405 	},
1406 #endif /* CONFIG_ARM64_RAS_EXTN */
1407 	{
1408 		.desc = "Data cache clean to the PoU not required for I/D coherence",
1409 		.capability = ARM64_HAS_CACHE_IDC,
1410 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1411 		.matches = has_cache_idc,
1412 		.cpu_enable = cpu_emulate_effective_ctr,
1413 	},
1414 	{
1415 		.desc = "Instruction cache invalidation not required for I/D coherence",
1416 		.capability = ARM64_HAS_CACHE_DIC,
1417 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1418 		.matches = has_cache_dic,
1419 	},
1420 	{
1421 		.desc = "Stage-2 Force Write-Back",
1422 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1423 		.capability = ARM64_HAS_STAGE2_FWB,
1424 		.sys_reg = SYS_ID_AA64MMFR2_EL1,
1425 		.sign = FTR_UNSIGNED,
1426 		.field_pos = ID_AA64MMFR2_FWB_SHIFT,
1427 		.min_field_value = 1,
1428 		.matches = has_cpuid_feature,
1429 		.cpu_enable = cpu_has_fwb,
1430 	},
1431 #ifdef CONFIG_ARM64_HW_AFDBM
1432 	{
1433 		/*
1434 		 * Since we turn this on always, we don't want the user to
1435 		 * think that the feature is available when it may not be.
1436 		 * So hide the description.
1437 		 *
1438 		 * .desc = "Hardware pagetable Dirty Bit Management",
1439 		 *
1440 		 */
1441 		.type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE,
1442 		.capability = ARM64_HW_DBM,
1443 		.sys_reg = SYS_ID_AA64MMFR1_EL1,
1444 		.sign = FTR_UNSIGNED,
1445 		.field_pos = ID_AA64MMFR1_HADBS_SHIFT,
1446 		.min_field_value = 2,
1447 		.matches = has_hw_dbm,
1448 		.cpu_enable = cpu_enable_hw_dbm,
1449 	},
1450 #endif
1451 	{
1452 		.desc = "CRC32 instructions",
1453 		.capability = ARM64_HAS_CRC32,
1454 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1455 		.matches = has_cpuid_feature,
1456 		.sys_reg = SYS_ID_AA64ISAR0_EL1,
1457 		.field_pos = ID_AA64ISAR0_CRC32_SHIFT,
1458 		.min_field_value = 1,
1459 	},
1460 #ifdef CONFIG_ARM64_SSBD
1461 	{
1462 		.desc = "Speculative Store Bypassing Safe (SSBS)",
1463 		.capability = ARM64_SSBS,
1464 		.type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE,
1465 		.matches = has_cpuid_feature,
1466 		.sys_reg = SYS_ID_AA64PFR1_EL1,
1467 		.field_pos = ID_AA64PFR1_SSBS_SHIFT,
1468 		.sign = FTR_UNSIGNED,
1469 		.min_field_value = ID_AA64PFR1_SSBS_PSTATE_ONLY,
1470 		.cpu_enable = cpu_enable_ssbs,
1471 	},
1472 #endif
1473 #ifdef CONFIG_ARM64_CNP
1474 	{
1475 		.desc = "Common not Private translations",
1476 		.capability = ARM64_HAS_CNP,
1477 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1478 		.matches = has_useable_cnp,
1479 		.sys_reg = SYS_ID_AA64MMFR2_EL1,
1480 		.sign = FTR_UNSIGNED,
1481 		.field_pos = ID_AA64MMFR2_CNP_SHIFT,
1482 		.min_field_value = 1,
1483 		.cpu_enable = cpu_enable_cnp,
1484 	},
1485 #endif
1486 	{
1487 		.desc = "Speculation barrier (SB)",
1488 		.capability = ARM64_HAS_SB,
1489 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1490 		.matches = has_cpuid_feature,
1491 		.sys_reg = SYS_ID_AA64ISAR1_EL1,
1492 		.field_pos = ID_AA64ISAR1_SB_SHIFT,
1493 		.sign = FTR_UNSIGNED,
1494 		.min_field_value = 1,
1495 	},
1496 #ifdef CONFIG_ARM64_PTR_AUTH
1497 	{
1498 		.desc = "Address authentication (architected algorithm)",
1499 		.capability = ARM64_HAS_ADDRESS_AUTH_ARCH,
1500 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1501 		.sys_reg = SYS_ID_AA64ISAR1_EL1,
1502 		.sign = FTR_UNSIGNED,
1503 		.field_pos = ID_AA64ISAR1_APA_SHIFT,
1504 		.min_field_value = ID_AA64ISAR1_APA_ARCHITECTED,
1505 		.matches = has_cpuid_feature,
1506 		.cpu_enable = cpu_enable_address_auth,
1507 	},
1508 	{
1509 		.desc = "Address authentication (IMP DEF algorithm)",
1510 		.capability = ARM64_HAS_ADDRESS_AUTH_IMP_DEF,
1511 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1512 		.sys_reg = SYS_ID_AA64ISAR1_EL1,
1513 		.sign = FTR_UNSIGNED,
1514 		.field_pos = ID_AA64ISAR1_API_SHIFT,
1515 		.min_field_value = ID_AA64ISAR1_API_IMP_DEF,
1516 		.matches = has_cpuid_feature,
1517 		.cpu_enable = cpu_enable_address_auth,
1518 	},
1519 	{
1520 		.desc = "Generic authentication (architected algorithm)",
1521 		.capability = ARM64_HAS_GENERIC_AUTH_ARCH,
1522 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1523 		.sys_reg = SYS_ID_AA64ISAR1_EL1,
1524 		.sign = FTR_UNSIGNED,
1525 		.field_pos = ID_AA64ISAR1_GPA_SHIFT,
1526 		.min_field_value = ID_AA64ISAR1_GPA_ARCHITECTED,
1527 		.matches = has_cpuid_feature,
1528 	},
1529 	{
1530 		.desc = "Generic authentication (IMP DEF algorithm)",
1531 		.capability = ARM64_HAS_GENERIC_AUTH_IMP_DEF,
1532 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1533 		.sys_reg = SYS_ID_AA64ISAR1_EL1,
1534 		.sign = FTR_UNSIGNED,
1535 		.field_pos = ID_AA64ISAR1_GPI_SHIFT,
1536 		.min_field_value = ID_AA64ISAR1_GPI_IMP_DEF,
1537 		.matches = has_cpuid_feature,
1538 	},
1539 #endif /* CONFIG_ARM64_PTR_AUTH */
1540 #ifdef CONFIG_ARM64_PSEUDO_NMI
1541 	{
1542 		/*
1543 		 * Depends on having GICv3
1544 		 */
1545 		.desc = "IRQ priority masking",
1546 		.capability = ARM64_HAS_IRQ_PRIO_MASKING,
1547 		.type = ARM64_CPUCAP_STRICT_BOOT_CPU_FEATURE,
1548 		.matches = can_use_gic_priorities,
1549 		.sys_reg = SYS_ID_AA64PFR0_EL1,
1550 		.field_pos = ID_AA64PFR0_GIC_SHIFT,
1551 		.sign = FTR_UNSIGNED,
1552 		.min_field_value = 1,
1553 	},
1554 #endif
1555 	{},
1556 };
1557 
1558 #define HWCAP_CPUID_MATCH(reg, field, s, min_value)				\
1559 		.matches = has_cpuid_feature,					\
1560 		.sys_reg = reg,							\
1561 		.field_pos = field,						\
1562 		.sign = s,							\
1563 		.min_field_value = min_value,
1564 
1565 #define __HWCAP_CAP(name, cap_type, cap)					\
1566 		.desc = name,							\
1567 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,				\
1568 		.hwcap_type = cap_type,						\
1569 		.hwcap = cap,							\
1570 
1571 #define HWCAP_CAP(reg, field, s, min_value, cap_type, cap)			\
1572 	{									\
1573 		__HWCAP_CAP(#cap, cap_type, cap)				\
1574 		HWCAP_CPUID_MATCH(reg, field, s, min_value)			\
1575 	}
1576 
1577 #define HWCAP_MULTI_CAP(list, cap_type, cap)					\
1578 	{									\
1579 		__HWCAP_CAP(#cap, cap_type, cap)				\
1580 		.matches = cpucap_multi_entry_cap_matches,			\
1581 		.match_list = list,						\
1582 	}
1583 
1584 #ifdef CONFIG_ARM64_PTR_AUTH
1585 static const struct arm64_cpu_capabilities ptr_auth_hwcap_addr_matches[] = {
1586 	{
1587 		HWCAP_CPUID_MATCH(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_APA_SHIFT,
1588 				  FTR_UNSIGNED, ID_AA64ISAR1_APA_ARCHITECTED)
1589 	},
1590 	{
1591 		HWCAP_CPUID_MATCH(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_API_SHIFT,
1592 				  FTR_UNSIGNED, ID_AA64ISAR1_API_IMP_DEF)
1593 	},
1594 	{},
1595 };
1596 
1597 static const struct arm64_cpu_capabilities ptr_auth_hwcap_gen_matches[] = {
1598 	{
1599 		HWCAP_CPUID_MATCH(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_GPA_SHIFT,
1600 				  FTR_UNSIGNED, ID_AA64ISAR1_GPA_ARCHITECTED)
1601 	},
1602 	{
1603 		HWCAP_CPUID_MATCH(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_GPI_SHIFT,
1604 				  FTR_UNSIGNED, ID_AA64ISAR1_GPI_IMP_DEF)
1605 	},
1606 	{},
1607 };
1608 #endif
1609 
1610 static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
1611 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_AES_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, KERNEL_HWCAP_PMULL),
1612 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_AES_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_AES),
1613 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA1_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_SHA1),
1614 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA2_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_SHA2),
1615 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA2_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, KERNEL_HWCAP_SHA512),
1616 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_CRC32_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_CRC32),
1617 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_ATOMICS_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, KERNEL_HWCAP_ATOMICS),
1618 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_RDM_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_ASIMDRDM),
1619 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA3_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_SHA3),
1620 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SM3_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_SM3),
1621 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SM4_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_SM4),
1622 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_DP_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_ASIMDDP),
1623 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_FHM_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_ASIMDFHM),
1624 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_TS_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_FLAGM),
1625 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_TS_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, KERNEL_HWCAP_FLAGM2),
1626 	HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_FP_SHIFT, FTR_SIGNED, 0, CAP_HWCAP, KERNEL_HWCAP_FP),
1627 	HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_FP_SHIFT, FTR_SIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_FPHP),
1628 	HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_ASIMD_SHIFT, FTR_SIGNED, 0, CAP_HWCAP, KERNEL_HWCAP_ASIMD),
1629 	HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_ASIMD_SHIFT, FTR_SIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_ASIMDHP),
1630 	HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_DIT_SHIFT, FTR_SIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_DIT),
1631 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_DPB_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_DCPOP),
1632 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_DPB_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, KERNEL_HWCAP_DCPODP),
1633 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_JSCVT_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_JSCVT),
1634 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_FCMA_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_FCMA),
1635 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_LRCPC_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_LRCPC),
1636 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_LRCPC_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, KERNEL_HWCAP_ILRCPC),
1637 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_FRINTTS_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_FRINT),
1638 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_SB_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_SB),
1639 	HWCAP_CAP(SYS_ID_AA64MMFR2_EL1, ID_AA64MMFR2_AT_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_USCAT),
1640 #ifdef CONFIG_ARM64_SVE
1641 	HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_SVE_SHIFT, FTR_UNSIGNED, ID_AA64PFR0_SVE, CAP_HWCAP, KERNEL_HWCAP_SVE),
1642 	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_SVEVER_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_SVEVER_SVE2, CAP_HWCAP, KERNEL_HWCAP_SVE2),
1643 	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_AES_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_AES, CAP_HWCAP, KERNEL_HWCAP_SVEAES),
1644 	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_AES_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_AES_PMULL, CAP_HWCAP, KERNEL_HWCAP_SVEPMULL),
1645 	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_BITPERM_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_BITPERM, CAP_HWCAP, KERNEL_HWCAP_SVEBITPERM),
1646 	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_SHA3_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_SHA3, CAP_HWCAP, KERNEL_HWCAP_SVESHA3),
1647 	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_SM4_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_SM4, CAP_HWCAP, KERNEL_HWCAP_SVESM4),
1648 #endif
1649 	HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_SSBS_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_SSBS_PSTATE_INSNS, CAP_HWCAP, KERNEL_HWCAP_SSBS),
1650 #ifdef CONFIG_ARM64_PTR_AUTH
1651 	HWCAP_MULTI_CAP(ptr_auth_hwcap_addr_matches, CAP_HWCAP, KERNEL_HWCAP_PACA),
1652 	HWCAP_MULTI_CAP(ptr_auth_hwcap_gen_matches, CAP_HWCAP, KERNEL_HWCAP_PACG),
1653 #endif
1654 	{},
1655 };
1656 
1657 static const struct arm64_cpu_capabilities compat_elf_hwcaps[] = {
1658 #ifdef CONFIG_COMPAT
1659 	HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_AES_SHIFT, FTR_UNSIGNED, 2, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_PMULL),
1660 	HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_AES_SHIFT, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_AES),
1661 	HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_SHA1_SHIFT, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_SHA1),
1662 	HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_SHA2_SHIFT, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_SHA2),
1663 	HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_CRC32_SHIFT, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_CRC32),
1664 #endif
1665 	{},
1666 };
1667 
1668 static void __init cap_set_elf_hwcap(const struct arm64_cpu_capabilities *cap)
1669 {
1670 	switch (cap->hwcap_type) {
1671 	case CAP_HWCAP:
1672 		cpu_set_feature(cap->hwcap);
1673 		break;
1674 #ifdef CONFIG_COMPAT
1675 	case CAP_COMPAT_HWCAP:
1676 		compat_elf_hwcap |= (u32)cap->hwcap;
1677 		break;
1678 	case CAP_COMPAT_HWCAP2:
1679 		compat_elf_hwcap2 |= (u32)cap->hwcap;
1680 		break;
1681 #endif
1682 	default:
1683 		WARN_ON(1);
1684 		break;
1685 	}
1686 }
1687 
1688 /* Check if we have a particular HWCAP enabled */
1689 static bool cpus_have_elf_hwcap(const struct arm64_cpu_capabilities *cap)
1690 {
1691 	bool rc;
1692 
1693 	switch (cap->hwcap_type) {
1694 	case CAP_HWCAP:
1695 		rc = cpu_have_feature(cap->hwcap);
1696 		break;
1697 #ifdef CONFIG_COMPAT
1698 	case CAP_COMPAT_HWCAP:
1699 		rc = (compat_elf_hwcap & (u32)cap->hwcap) != 0;
1700 		break;
1701 	case CAP_COMPAT_HWCAP2:
1702 		rc = (compat_elf_hwcap2 & (u32)cap->hwcap) != 0;
1703 		break;
1704 #endif
1705 	default:
1706 		WARN_ON(1);
1707 		rc = false;
1708 	}
1709 
1710 	return rc;
1711 }
1712 
1713 static void __init setup_elf_hwcaps(const struct arm64_cpu_capabilities *hwcaps)
1714 {
1715 	/* We support emulation of accesses to CPU ID feature registers */
1716 	cpu_set_named_feature(CPUID);
1717 	for (; hwcaps->matches; hwcaps++)
1718 		if (hwcaps->matches(hwcaps, cpucap_default_scope(hwcaps)))
1719 			cap_set_elf_hwcap(hwcaps);
1720 }
1721 
1722 static void update_cpu_capabilities(u16 scope_mask)
1723 {
1724 	int i;
1725 	const struct arm64_cpu_capabilities *caps;
1726 
1727 	scope_mask &= ARM64_CPUCAP_SCOPE_MASK;
1728 	for (i = 0; i < ARM64_NCAPS; i++) {
1729 		caps = cpu_hwcaps_ptrs[i];
1730 		if (!caps || !(caps->type & scope_mask) ||
1731 		    cpus_have_cap(caps->capability) ||
1732 		    !caps->matches(caps, cpucap_default_scope(caps)))
1733 			continue;
1734 
1735 		if (caps->desc)
1736 			pr_info("detected: %s\n", caps->desc);
1737 		cpus_set_cap(caps->capability);
1738 
1739 		if ((scope_mask & SCOPE_BOOT_CPU) && (caps->type & SCOPE_BOOT_CPU))
1740 			set_bit(caps->capability, boot_capabilities);
1741 	}
1742 }
1743 
1744 /*
1745  * Enable all the available capabilities on this CPU. The capabilities
1746  * with BOOT_CPU scope are handled separately and hence skipped here.
1747  */
1748 static int cpu_enable_non_boot_scope_capabilities(void *__unused)
1749 {
1750 	int i;
1751 	u16 non_boot_scope = SCOPE_ALL & ~SCOPE_BOOT_CPU;
1752 
1753 	for_each_available_cap(i) {
1754 		const struct arm64_cpu_capabilities *cap = cpu_hwcaps_ptrs[i];
1755 
1756 		if (WARN_ON(!cap))
1757 			continue;
1758 
1759 		if (!(cap->type & non_boot_scope))
1760 			continue;
1761 
1762 		if (cap->cpu_enable)
1763 			cap->cpu_enable(cap);
1764 	}
1765 	return 0;
1766 }
1767 
1768 /*
1769  * Run through the enabled capabilities and enable() it on all active
1770  * CPUs
1771  */
1772 static void __init enable_cpu_capabilities(u16 scope_mask)
1773 {
1774 	int i;
1775 	const struct arm64_cpu_capabilities *caps;
1776 	bool boot_scope;
1777 
1778 	scope_mask &= ARM64_CPUCAP_SCOPE_MASK;
1779 	boot_scope = !!(scope_mask & SCOPE_BOOT_CPU);
1780 
1781 	for (i = 0; i < ARM64_NCAPS; i++) {
1782 		unsigned int num;
1783 
1784 		caps = cpu_hwcaps_ptrs[i];
1785 		if (!caps || !(caps->type & scope_mask))
1786 			continue;
1787 		num = caps->capability;
1788 		if (!cpus_have_cap(num))
1789 			continue;
1790 
1791 		/* Ensure cpus_have_const_cap(num) works */
1792 		static_branch_enable(&cpu_hwcap_keys[num]);
1793 
1794 		if (boot_scope && caps->cpu_enable)
1795 			/*
1796 			 * Capabilities with SCOPE_BOOT_CPU scope are finalised
1797 			 * before any secondary CPU boots. Thus, each secondary
1798 			 * will enable the capability as appropriate via
1799 			 * check_local_cpu_capabilities(). The only exception is
1800 			 * the boot CPU, for which the capability must be
1801 			 * enabled here. This approach avoids costly
1802 			 * stop_machine() calls for this case.
1803 			 */
1804 			caps->cpu_enable(caps);
1805 	}
1806 
1807 	/*
1808 	 * For all non-boot scope capabilities, use stop_machine()
1809 	 * as it schedules the work allowing us to modify PSTATE,
1810 	 * instead of on_each_cpu() which uses an IPI, giving us a
1811 	 * PSTATE that disappears when we return.
1812 	 */
1813 	if (!boot_scope)
1814 		stop_machine(cpu_enable_non_boot_scope_capabilities,
1815 			     NULL, cpu_online_mask);
1816 }
1817 
1818 /*
1819  * Run through the list of capabilities to check for conflicts.
1820  * If the system has already detected a capability, take necessary
1821  * action on this CPU.
1822  *
1823  * Returns "false" on conflicts.
1824  */
1825 static bool verify_local_cpu_caps(u16 scope_mask)
1826 {
1827 	int i;
1828 	bool cpu_has_cap, system_has_cap;
1829 	const struct arm64_cpu_capabilities *caps;
1830 
1831 	scope_mask &= ARM64_CPUCAP_SCOPE_MASK;
1832 
1833 	for (i = 0; i < ARM64_NCAPS; i++) {
1834 		caps = cpu_hwcaps_ptrs[i];
1835 		if (!caps || !(caps->type & scope_mask))
1836 			continue;
1837 
1838 		cpu_has_cap = caps->matches(caps, SCOPE_LOCAL_CPU);
1839 		system_has_cap = cpus_have_cap(caps->capability);
1840 
1841 		if (system_has_cap) {
1842 			/*
1843 			 * Check if the new CPU misses an advertised feature,
1844 			 * which is not safe to miss.
1845 			 */
1846 			if (!cpu_has_cap && !cpucap_late_cpu_optional(caps))
1847 				break;
1848 			/*
1849 			 * We have to issue cpu_enable() irrespective of
1850 			 * whether the CPU has it or not, as it is enabeld
1851 			 * system wide. It is upto the call back to take
1852 			 * appropriate action on this CPU.
1853 			 */
1854 			if (caps->cpu_enable)
1855 				caps->cpu_enable(caps);
1856 		} else {
1857 			/*
1858 			 * Check if the CPU has this capability if it isn't
1859 			 * safe to have when the system doesn't.
1860 			 */
1861 			if (cpu_has_cap && !cpucap_late_cpu_permitted(caps))
1862 				break;
1863 		}
1864 	}
1865 
1866 	if (i < ARM64_NCAPS) {
1867 		pr_crit("CPU%d: Detected conflict for capability %d (%s), System: %d, CPU: %d\n",
1868 			smp_processor_id(), caps->capability,
1869 			caps->desc, system_has_cap, cpu_has_cap);
1870 		return false;
1871 	}
1872 
1873 	return true;
1874 }
1875 
1876 /*
1877  * Check for CPU features that are used in early boot
1878  * based on the Boot CPU value.
1879  */
1880 static void check_early_cpu_features(void)
1881 {
1882 	verify_cpu_asid_bits();
1883 	/*
1884 	 * Early features are used by the kernel already. If there
1885 	 * is a conflict, we cannot proceed further.
1886 	 */
1887 	if (!verify_local_cpu_caps(SCOPE_BOOT_CPU))
1888 		cpu_panic_kernel();
1889 }
1890 
1891 static void
1892 verify_local_elf_hwcaps(const struct arm64_cpu_capabilities *caps)
1893 {
1894 
1895 	for (; caps->matches; caps++)
1896 		if (cpus_have_elf_hwcap(caps) && !caps->matches(caps, SCOPE_LOCAL_CPU)) {
1897 			pr_crit("CPU%d: missing HWCAP: %s\n",
1898 					smp_processor_id(), caps->desc);
1899 			cpu_die_early();
1900 		}
1901 }
1902 
1903 static void verify_sve_features(void)
1904 {
1905 	u64 safe_zcr = read_sanitised_ftr_reg(SYS_ZCR_EL1);
1906 	u64 zcr = read_zcr_features();
1907 
1908 	unsigned int safe_len = safe_zcr & ZCR_ELx_LEN_MASK;
1909 	unsigned int len = zcr & ZCR_ELx_LEN_MASK;
1910 
1911 	if (len < safe_len || sve_verify_vq_map()) {
1912 		pr_crit("CPU%d: SVE: vector length support mismatch\n",
1913 			smp_processor_id());
1914 		cpu_die_early();
1915 	}
1916 
1917 	/* Add checks on other ZCR bits here if necessary */
1918 }
1919 
1920 
1921 /*
1922  * Run through the enabled system capabilities and enable() it on this CPU.
1923  * The capabilities were decided based on the available CPUs at the boot time.
1924  * Any new CPU should match the system wide status of the capability. If the
1925  * new CPU doesn't have a capability which the system now has enabled, we
1926  * cannot do anything to fix it up and could cause unexpected failures. So
1927  * we park the CPU.
1928  */
1929 static void verify_local_cpu_capabilities(void)
1930 {
1931 	/*
1932 	 * The capabilities with SCOPE_BOOT_CPU are checked from
1933 	 * check_early_cpu_features(), as they need to be verified
1934 	 * on all secondary CPUs.
1935 	 */
1936 	if (!verify_local_cpu_caps(SCOPE_ALL & ~SCOPE_BOOT_CPU))
1937 		cpu_die_early();
1938 
1939 	verify_local_elf_hwcaps(arm64_elf_hwcaps);
1940 
1941 	if (system_supports_32bit_el0())
1942 		verify_local_elf_hwcaps(compat_elf_hwcaps);
1943 
1944 	if (system_supports_sve())
1945 		verify_sve_features();
1946 }
1947 
1948 void check_local_cpu_capabilities(void)
1949 {
1950 	/*
1951 	 * All secondary CPUs should conform to the early CPU features
1952 	 * in use by the kernel based on boot CPU.
1953 	 */
1954 	check_early_cpu_features();
1955 
1956 	/*
1957 	 * If we haven't finalised the system capabilities, this CPU gets
1958 	 * a chance to update the errata work arounds and local features.
1959 	 * Otherwise, this CPU should verify that it has all the system
1960 	 * advertised capabilities.
1961 	 */
1962 	if (!sys_caps_initialised)
1963 		update_cpu_capabilities(SCOPE_LOCAL_CPU);
1964 	else
1965 		verify_local_cpu_capabilities();
1966 }
1967 
1968 static void __init setup_boot_cpu_capabilities(void)
1969 {
1970 	/* Detect capabilities with either SCOPE_BOOT_CPU or SCOPE_LOCAL_CPU */
1971 	update_cpu_capabilities(SCOPE_BOOT_CPU | SCOPE_LOCAL_CPU);
1972 	/* Enable the SCOPE_BOOT_CPU capabilities alone right away */
1973 	enable_cpu_capabilities(SCOPE_BOOT_CPU);
1974 }
1975 
1976 DEFINE_STATIC_KEY_FALSE(arm64_const_caps_ready);
1977 EXPORT_SYMBOL(arm64_const_caps_ready);
1978 
1979 static void __init mark_const_caps_ready(void)
1980 {
1981 	static_branch_enable(&arm64_const_caps_ready);
1982 }
1983 
1984 bool this_cpu_has_cap(unsigned int n)
1985 {
1986 	if (!WARN_ON(preemptible()) && n < ARM64_NCAPS) {
1987 		const struct arm64_cpu_capabilities *cap = cpu_hwcaps_ptrs[n];
1988 
1989 		if (cap)
1990 			return cap->matches(cap, SCOPE_LOCAL_CPU);
1991 	}
1992 
1993 	return false;
1994 }
1995 
1996 void cpu_set_feature(unsigned int num)
1997 {
1998 	WARN_ON(num >= MAX_CPU_FEATURES);
1999 	elf_hwcap |= BIT(num);
2000 }
2001 EXPORT_SYMBOL_GPL(cpu_set_feature);
2002 
2003 bool cpu_have_feature(unsigned int num)
2004 {
2005 	WARN_ON(num >= MAX_CPU_FEATURES);
2006 	return elf_hwcap & BIT(num);
2007 }
2008 EXPORT_SYMBOL_GPL(cpu_have_feature);
2009 
2010 unsigned long cpu_get_elf_hwcap(void)
2011 {
2012 	/*
2013 	 * We currently only populate the first 32 bits of AT_HWCAP. Please
2014 	 * note that for userspace compatibility we guarantee that bits 62
2015 	 * and 63 will always be returned as 0.
2016 	 */
2017 	return lower_32_bits(elf_hwcap);
2018 }
2019 
2020 unsigned long cpu_get_elf_hwcap2(void)
2021 {
2022 	return upper_32_bits(elf_hwcap);
2023 }
2024 
2025 static void __init setup_system_capabilities(void)
2026 {
2027 	/*
2028 	 * We have finalised the system-wide safe feature
2029 	 * registers, finalise the capabilities that depend
2030 	 * on it. Also enable all the available capabilities,
2031 	 * that are not enabled already.
2032 	 */
2033 	update_cpu_capabilities(SCOPE_SYSTEM);
2034 	enable_cpu_capabilities(SCOPE_ALL & ~SCOPE_BOOT_CPU);
2035 }
2036 
2037 void __init setup_cpu_features(void)
2038 {
2039 	u32 cwg;
2040 
2041 	setup_system_capabilities();
2042 	mark_const_caps_ready();
2043 	setup_elf_hwcaps(arm64_elf_hwcaps);
2044 
2045 	if (system_supports_32bit_el0())
2046 		setup_elf_hwcaps(compat_elf_hwcaps);
2047 
2048 	if (system_uses_ttbr0_pan())
2049 		pr_info("emulated: Privileged Access Never (PAN) using TTBR0_EL1 switching\n");
2050 
2051 	sve_setup();
2052 	minsigstksz_setup();
2053 
2054 	/* Advertise that we have computed the system capabilities */
2055 	set_sys_caps_initialised();
2056 
2057 	/*
2058 	 * Check for sane CTR_EL0.CWG value.
2059 	 */
2060 	cwg = cache_type_cwg();
2061 	if (!cwg)
2062 		pr_warn("No Cache Writeback Granule information, assuming %d\n",
2063 			ARCH_DMA_MINALIGN);
2064 }
2065 
2066 static bool __maybe_unused
2067 cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused)
2068 {
2069 	return (cpus_have_const_cap(ARM64_HAS_PAN) && !cpus_have_const_cap(ARM64_HAS_UAO));
2070 }
2071 
2072 static void __maybe_unused cpu_enable_cnp(struct arm64_cpu_capabilities const *cap)
2073 {
2074 	cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
2075 }
2076 
2077 /*
2078  * We emulate only the following system register space.
2079  * Op0 = 0x3, CRn = 0x0, Op1 = 0x0, CRm = [0, 4 - 7]
2080  * See Table C5-6 System instruction encodings for System register accesses,
2081  * ARMv8 ARM(ARM DDI 0487A.f) for more details.
2082  */
2083 static inline bool __attribute_const__ is_emulated(u32 id)
2084 {
2085 	return (sys_reg_Op0(id) == 0x3 &&
2086 		sys_reg_CRn(id) == 0x0 &&
2087 		sys_reg_Op1(id) == 0x0 &&
2088 		(sys_reg_CRm(id) == 0 ||
2089 		 ((sys_reg_CRm(id) >= 4) && (sys_reg_CRm(id) <= 7))));
2090 }
2091 
2092 /*
2093  * With CRm == 0, reg should be one of :
2094  * MIDR_EL1, MPIDR_EL1 or REVIDR_EL1.
2095  */
2096 static inline int emulate_id_reg(u32 id, u64 *valp)
2097 {
2098 	switch (id) {
2099 	case SYS_MIDR_EL1:
2100 		*valp = read_cpuid_id();
2101 		break;
2102 	case SYS_MPIDR_EL1:
2103 		*valp = SYS_MPIDR_SAFE_VAL;
2104 		break;
2105 	case SYS_REVIDR_EL1:
2106 		/* IMPLEMENTATION DEFINED values are emulated with 0 */
2107 		*valp = 0;
2108 		break;
2109 	default:
2110 		return -EINVAL;
2111 	}
2112 
2113 	return 0;
2114 }
2115 
2116 static int emulate_sys_reg(u32 id, u64 *valp)
2117 {
2118 	struct arm64_ftr_reg *regp;
2119 
2120 	if (!is_emulated(id))
2121 		return -EINVAL;
2122 
2123 	if (sys_reg_CRm(id) == 0)
2124 		return emulate_id_reg(id, valp);
2125 
2126 	regp = get_arm64_ftr_reg(id);
2127 	if (regp)
2128 		*valp = arm64_ftr_reg_user_value(regp);
2129 	else
2130 		/*
2131 		 * The untracked registers are either IMPLEMENTATION DEFINED
2132 		 * (e.g, ID_AFR0_EL1) or reserved RAZ.
2133 		 */
2134 		*valp = 0;
2135 	return 0;
2136 }
2137 
2138 int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt)
2139 {
2140 	int rc;
2141 	u64 val;
2142 
2143 	rc = emulate_sys_reg(sys_reg, &val);
2144 	if (!rc) {
2145 		pt_regs_write_reg(regs, rt, val);
2146 		arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
2147 	}
2148 	return rc;
2149 }
2150 
2151 static int emulate_mrs(struct pt_regs *regs, u32 insn)
2152 {
2153 	u32 sys_reg, rt;
2154 
2155 	/*
2156 	 * sys_reg values are defined as used in mrs/msr instruction.
2157 	 * shift the imm value to get the encoding.
2158 	 */
2159 	sys_reg = (u32)aarch64_insn_decode_immediate(AARCH64_INSN_IMM_16, insn) << 5;
2160 	rt = aarch64_insn_decode_register(AARCH64_INSN_REGTYPE_RT, insn);
2161 	return do_emulate_mrs(regs, sys_reg, rt);
2162 }
2163 
2164 static struct undef_hook mrs_hook = {
2165 	.instr_mask = 0xfff00000,
2166 	.instr_val  = 0xd5300000,
2167 	.pstate_mask = PSR_AA32_MODE_MASK,
2168 	.pstate_val = PSR_MODE_EL0t,
2169 	.fn = emulate_mrs,
2170 };
2171 
2172 static int __init enable_mrs_emulation(void)
2173 {
2174 	register_undef_hook(&mrs_hook);
2175 	return 0;
2176 }
2177 
2178 core_initcall(enable_mrs_emulation);
2179 
2180 ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr,
2181 			  char *buf)
2182 {
2183 	if (__meltdown_safe)
2184 		return sprintf(buf, "Not affected\n");
2185 
2186 	if (arm64_kernel_unmapped_at_el0())
2187 		return sprintf(buf, "Mitigation: PTI\n");
2188 
2189 	return sprintf(buf, "Vulnerable\n");
2190 }
2191