xref: /openbmc/linux/arch/arm64/kernel/cpufeature.c (revision b830f94f)
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_SAFE, CTR_CWG_SHIFT, 4, 0),
229 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_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_SAFE:
472 		ret = new > cur ? new : cur;
473 		break;
474 	default:
475 		BUG();
476 	}
477 
478 	return ret;
479 }
480 
481 static void __init sort_ftr_regs(void)
482 {
483 	int i;
484 
485 	/* Check that the array is sorted so that we can do the binary search */
486 	for (i = 1; i < ARRAY_SIZE(arm64_ftr_regs); i++)
487 		BUG_ON(arm64_ftr_regs[i].sys_id < arm64_ftr_regs[i - 1].sys_id);
488 }
489 
490 /*
491  * Initialise the CPU feature register from Boot CPU values.
492  * Also initiliases the strict_mask for the register.
493  * Any bits that are not covered by an arm64_ftr_bits entry are considered
494  * RES0 for the system-wide value, and must strictly match.
495  */
496 static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new)
497 {
498 	u64 val = 0;
499 	u64 strict_mask = ~0x0ULL;
500 	u64 user_mask = 0;
501 	u64 valid_mask = 0;
502 
503 	const struct arm64_ftr_bits *ftrp;
504 	struct arm64_ftr_reg *reg = get_arm64_ftr_reg(sys_reg);
505 
506 	BUG_ON(!reg);
507 
508 	for (ftrp  = reg->ftr_bits; ftrp->width; ftrp++) {
509 		u64 ftr_mask = arm64_ftr_mask(ftrp);
510 		s64 ftr_new = arm64_ftr_value(ftrp, new);
511 
512 		val = arm64_ftr_set_value(ftrp, val, ftr_new);
513 
514 		valid_mask |= ftr_mask;
515 		if (!ftrp->strict)
516 			strict_mask &= ~ftr_mask;
517 		if (ftrp->visible)
518 			user_mask |= ftr_mask;
519 		else
520 			reg->user_val = arm64_ftr_set_value(ftrp,
521 							    reg->user_val,
522 							    ftrp->safe_val);
523 	}
524 
525 	val &= valid_mask;
526 
527 	reg->sys_val = val;
528 	reg->strict_mask = strict_mask;
529 	reg->user_mask = user_mask;
530 }
531 
532 extern const struct arm64_cpu_capabilities arm64_errata[];
533 static const struct arm64_cpu_capabilities arm64_features[];
534 
535 static void __init
536 init_cpu_hwcaps_indirect_list_from_array(const struct arm64_cpu_capabilities *caps)
537 {
538 	for (; caps->matches; caps++) {
539 		if (WARN(caps->capability >= ARM64_NCAPS,
540 			"Invalid capability %d\n", caps->capability))
541 			continue;
542 		if (WARN(cpu_hwcaps_ptrs[caps->capability],
543 			"Duplicate entry for capability %d\n",
544 			caps->capability))
545 			continue;
546 		cpu_hwcaps_ptrs[caps->capability] = caps;
547 	}
548 }
549 
550 static void __init init_cpu_hwcaps_indirect_list(void)
551 {
552 	init_cpu_hwcaps_indirect_list_from_array(arm64_features);
553 	init_cpu_hwcaps_indirect_list_from_array(arm64_errata);
554 }
555 
556 static void __init setup_boot_cpu_capabilities(void);
557 
558 void __init init_cpu_features(struct cpuinfo_arm64 *info)
559 {
560 	/* Before we start using the tables, make sure it is sorted */
561 	sort_ftr_regs();
562 
563 	init_cpu_ftr_reg(SYS_CTR_EL0, info->reg_ctr);
564 	init_cpu_ftr_reg(SYS_DCZID_EL0, info->reg_dczid);
565 	init_cpu_ftr_reg(SYS_CNTFRQ_EL0, info->reg_cntfrq);
566 	init_cpu_ftr_reg(SYS_ID_AA64DFR0_EL1, info->reg_id_aa64dfr0);
567 	init_cpu_ftr_reg(SYS_ID_AA64DFR1_EL1, info->reg_id_aa64dfr1);
568 	init_cpu_ftr_reg(SYS_ID_AA64ISAR0_EL1, info->reg_id_aa64isar0);
569 	init_cpu_ftr_reg(SYS_ID_AA64ISAR1_EL1, info->reg_id_aa64isar1);
570 	init_cpu_ftr_reg(SYS_ID_AA64MMFR0_EL1, info->reg_id_aa64mmfr0);
571 	init_cpu_ftr_reg(SYS_ID_AA64MMFR1_EL1, info->reg_id_aa64mmfr1);
572 	init_cpu_ftr_reg(SYS_ID_AA64MMFR2_EL1, info->reg_id_aa64mmfr2);
573 	init_cpu_ftr_reg(SYS_ID_AA64PFR0_EL1, info->reg_id_aa64pfr0);
574 	init_cpu_ftr_reg(SYS_ID_AA64PFR1_EL1, info->reg_id_aa64pfr1);
575 	init_cpu_ftr_reg(SYS_ID_AA64ZFR0_EL1, info->reg_id_aa64zfr0);
576 
577 	if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {
578 		init_cpu_ftr_reg(SYS_ID_DFR0_EL1, info->reg_id_dfr0);
579 		init_cpu_ftr_reg(SYS_ID_ISAR0_EL1, info->reg_id_isar0);
580 		init_cpu_ftr_reg(SYS_ID_ISAR1_EL1, info->reg_id_isar1);
581 		init_cpu_ftr_reg(SYS_ID_ISAR2_EL1, info->reg_id_isar2);
582 		init_cpu_ftr_reg(SYS_ID_ISAR3_EL1, info->reg_id_isar3);
583 		init_cpu_ftr_reg(SYS_ID_ISAR4_EL1, info->reg_id_isar4);
584 		init_cpu_ftr_reg(SYS_ID_ISAR5_EL1, info->reg_id_isar5);
585 		init_cpu_ftr_reg(SYS_ID_MMFR0_EL1, info->reg_id_mmfr0);
586 		init_cpu_ftr_reg(SYS_ID_MMFR1_EL1, info->reg_id_mmfr1);
587 		init_cpu_ftr_reg(SYS_ID_MMFR2_EL1, info->reg_id_mmfr2);
588 		init_cpu_ftr_reg(SYS_ID_MMFR3_EL1, info->reg_id_mmfr3);
589 		init_cpu_ftr_reg(SYS_ID_PFR0_EL1, info->reg_id_pfr0);
590 		init_cpu_ftr_reg(SYS_ID_PFR1_EL1, info->reg_id_pfr1);
591 		init_cpu_ftr_reg(SYS_MVFR0_EL1, info->reg_mvfr0);
592 		init_cpu_ftr_reg(SYS_MVFR1_EL1, info->reg_mvfr1);
593 		init_cpu_ftr_reg(SYS_MVFR2_EL1, info->reg_mvfr2);
594 	}
595 
596 	if (id_aa64pfr0_sve(info->reg_id_aa64pfr0)) {
597 		init_cpu_ftr_reg(SYS_ZCR_EL1, info->reg_zcr);
598 		sve_init_vq_map();
599 	}
600 
601 	/*
602 	 * Initialize the indirect array of CPU hwcaps capabilities pointers
603 	 * before we handle the boot CPU below.
604 	 */
605 	init_cpu_hwcaps_indirect_list();
606 
607 	/*
608 	 * Detect and enable early CPU capabilities based on the boot CPU,
609 	 * after we have initialised the CPU feature infrastructure.
610 	 */
611 	setup_boot_cpu_capabilities();
612 }
613 
614 static void update_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 new)
615 {
616 	const struct arm64_ftr_bits *ftrp;
617 
618 	for (ftrp = reg->ftr_bits; ftrp->width; ftrp++) {
619 		s64 ftr_cur = arm64_ftr_value(ftrp, reg->sys_val);
620 		s64 ftr_new = arm64_ftr_value(ftrp, new);
621 
622 		if (ftr_cur == ftr_new)
623 			continue;
624 		/* Find a safe value */
625 		ftr_new = arm64_ftr_safe_value(ftrp, ftr_new, ftr_cur);
626 		reg->sys_val = arm64_ftr_set_value(ftrp, reg->sys_val, ftr_new);
627 	}
628 
629 }
630 
631 static int check_update_ftr_reg(u32 sys_id, int cpu, u64 val, u64 boot)
632 {
633 	struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id);
634 
635 	BUG_ON(!regp);
636 	update_cpu_ftr_reg(regp, val);
637 	if ((boot & regp->strict_mask) == (val & regp->strict_mask))
638 		return 0;
639 	pr_warn("SANITY CHECK: Unexpected variation in %s. Boot CPU: %#016llx, CPU%d: %#016llx\n",
640 			regp->name, boot, cpu, val);
641 	return 1;
642 }
643 
644 /*
645  * Update system wide CPU feature registers with the values from a
646  * non-boot CPU. Also performs SANITY checks to make sure that there
647  * aren't any insane variations from that of the boot CPU.
648  */
649 void update_cpu_features(int cpu,
650 			 struct cpuinfo_arm64 *info,
651 			 struct cpuinfo_arm64 *boot)
652 {
653 	int taint = 0;
654 
655 	/*
656 	 * The kernel can handle differing I-cache policies, but otherwise
657 	 * caches should look identical. Userspace JITs will make use of
658 	 * *minLine.
659 	 */
660 	taint |= check_update_ftr_reg(SYS_CTR_EL0, cpu,
661 				      info->reg_ctr, boot->reg_ctr);
662 
663 	/*
664 	 * Userspace may perform DC ZVA instructions. Mismatched block sizes
665 	 * could result in too much or too little memory being zeroed if a
666 	 * process is preempted and migrated between CPUs.
667 	 */
668 	taint |= check_update_ftr_reg(SYS_DCZID_EL0, cpu,
669 				      info->reg_dczid, boot->reg_dczid);
670 
671 	/* If different, timekeeping will be broken (especially with KVM) */
672 	taint |= check_update_ftr_reg(SYS_CNTFRQ_EL0, cpu,
673 				      info->reg_cntfrq, boot->reg_cntfrq);
674 
675 	/*
676 	 * The kernel uses self-hosted debug features and expects CPUs to
677 	 * support identical debug features. We presently need CTX_CMPs, WRPs,
678 	 * and BRPs to be identical.
679 	 * ID_AA64DFR1 is currently RES0.
680 	 */
681 	taint |= check_update_ftr_reg(SYS_ID_AA64DFR0_EL1, cpu,
682 				      info->reg_id_aa64dfr0, boot->reg_id_aa64dfr0);
683 	taint |= check_update_ftr_reg(SYS_ID_AA64DFR1_EL1, cpu,
684 				      info->reg_id_aa64dfr1, boot->reg_id_aa64dfr1);
685 	/*
686 	 * Even in big.LITTLE, processors should be identical instruction-set
687 	 * wise.
688 	 */
689 	taint |= check_update_ftr_reg(SYS_ID_AA64ISAR0_EL1, cpu,
690 				      info->reg_id_aa64isar0, boot->reg_id_aa64isar0);
691 	taint |= check_update_ftr_reg(SYS_ID_AA64ISAR1_EL1, cpu,
692 				      info->reg_id_aa64isar1, boot->reg_id_aa64isar1);
693 
694 	/*
695 	 * Differing PARange support is fine as long as all peripherals and
696 	 * memory are mapped within the minimum PARange of all CPUs.
697 	 * Linux should not care about secure memory.
698 	 */
699 	taint |= check_update_ftr_reg(SYS_ID_AA64MMFR0_EL1, cpu,
700 				      info->reg_id_aa64mmfr0, boot->reg_id_aa64mmfr0);
701 	taint |= check_update_ftr_reg(SYS_ID_AA64MMFR1_EL1, cpu,
702 				      info->reg_id_aa64mmfr1, boot->reg_id_aa64mmfr1);
703 	taint |= check_update_ftr_reg(SYS_ID_AA64MMFR2_EL1, cpu,
704 				      info->reg_id_aa64mmfr2, boot->reg_id_aa64mmfr2);
705 
706 	/*
707 	 * EL3 is not our concern.
708 	 */
709 	taint |= check_update_ftr_reg(SYS_ID_AA64PFR0_EL1, cpu,
710 				      info->reg_id_aa64pfr0, boot->reg_id_aa64pfr0);
711 	taint |= check_update_ftr_reg(SYS_ID_AA64PFR1_EL1, cpu,
712 				      info->reg_id_aa64pfr1, boot->reg_id_aa64pfr1);
713 
714 	taint |= check_update_ftr_reg(SYS_ID_AA64ZFR0_EL1, cpu,
715 				      info->reg_id_aa64zfr0, boot->reg_id_aa64zfr0);
716 
717 	/*
718 	 * If we have AArch32, we care about 32-bit features for compat.
719 	 * If the system doesn't support AArch32, don't update them.
720 	 */
721 	if (id_aa64pfr0_32bit_el0(read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1)) &&
722 		id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {
723 
724 		taint |= check_update_ftr_reg(SYS_ID_DFR0_EL1, cpu,
725 					info->reg_id_dfr0, boot->reg_id_dfr0);
726 		taint |= check_update_ftr_reg(SYS_ID_ISAR0_EL1, cpu,
727 					info->reg_id_isar0, boot->reg_id_isar0);
728 		taint |= check_update_ftr_reg(SYS_ID_ISAR1_EL1, cpu,
729 					info->reg_id_isar1, boot->reg_id_isar1);
730 		taint |= check_update_ftr_reg(SYS_ID_ISAR2_EL1, cpu,
731 					info->reg_id_isar2, boot->reg_id_isar2);
732 		taint |= check_update_ftr_reg(SYS_ID_ISAR3_EL1, cpu,
733 					info->reg_id_isar3, boot->reg_id_isar3);
734 		taint |= check_update_ftr_reg(SYS_ID_ISAR4_EL1, cpu,
735 					info->reg_id_isar4, boot->reg_id_isar4);
736 		taint |= check_update_ftr_reg(SYS_ID_ISAR5_EL1, cpu,
737 					info->reg_id_isar5, boot->reg_id_isar5);
738 
739 		/*
740 		 * Regardless of the value of the AuxReg field, the AIFSR, ADFSR, and
741 		 * ACTLR formats could differ across CPUs and therefore would have to
742 		 * be trapped for virtualization anyway.
743 		 */
744 		taint |= check_update_ftr_reg(SYS_ID_MMFR0_EL1, cpu,
745 					info->reg_id_mmfr0, boot->reg_id_mmfr0);
746 		taint |= check_update_ftr_reg(SYS_ID_MMFR1_EL1, cpu,
747 					info->reg_id_mmfr1, boot->reg_id_mmfr1);
748 		taint |= check_update_ftr_reg(SYS_ID_MMFR2_EL1, cpu,
749 					info->reg_id_mmfr2, boot->reg_id_mmfr2);
750 		taint |= check_update_ftr_reg(SYS_ID_MMFR3_EL1, cpu,
751 					info->reg_id_mmfr3, boot->reg_id_mmfr3);
752 		taint |= check_update_ftr_reg(SYS_ID_PFR0_EL1, cpu,
753 					info->reg_id_pfr0, boot->reg_id_pfr0);
754 		taint |= check_update_ftr_reg(SYS_ID_PFR1_EL1, cpu,
755 					info->reg_id_pfr1, boot->reg_id_pfr1);
756 		taint |= check_update_ftr_reg(SYS_MVFR0_EL1, cpu,
757 					info->reg_mvfr0, boot->reg_mvfr0);
758 		taint |= check_update_ftr_reg(SYS_MVFR1_EL1, cpu,
759 					info->reg_mvfr1, boot->reg_mvfr1);
760 		taint |= check_update_ftr_reg(SYS_MVFR2_EL1, cpu,
761 					info->reg_mvfr2, boot->reg_mvfr2);
762 	}
763 
764 	if (id_aa64pfr0_sve(info->reg_id_aa64pfr0)) {
765 		taint |= check_update_ftr_reg(SYS_ZCR_EL1, cpu,
766 					info->reg_zcr, boot->reg_zcr);
767 
768 		/* Probe vector lengths, unless we already gave up on SVE */
769 		if (id_aa64pfr0_sve(read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1)) &&
770 		    !sys_caps_initialised)
771 			sve_update_vq_map();
772 	}
773 
774 	/*
775 	 * Mismatched CPU features are a recipe for disaster. Don't even
776 	 * pretend to support them.
777 	 */
778 	if (taint) {
779 		pr_warn_once("Unsupported CPU feature variation detected.\n");
780 		add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
781 	}
782 }
783 
784 u64 read_sanitised_ftr_reg(u32 id)
785 {
786 	struct arm64_ftr_reg *regp = get_arm64_ftr_reg(id);
787 
788 	/* We shouldn't get a request for an unsupported register */
789 	BUG_ON(!regp);
790 	return regp->sys_val;
791 }
792 
793 #define read_sysreg_case(r)	\
794 	case r:		return read_sysreg_s(r)
795 
796 /*
797  * __read_sysreg_by_encoding() - Used by a STARTING cpu before cpuinfo is populated.
798  * Read the system register on the current CPU
799  */
800 static u64 __read_sysreg_by_encoding(u32 sys_id)
801 {
802 	switch (sys_id) {
803 	read_sysreg_case(SYS_ID_PFR0_EL1);
804 	read_sysreg_case(SYS_ID_PFR1_EL1);
805 	read_sysreg_case(SYS_ID_DFR0_EL1);
806 	read_sysreg_case(SYS_ID_MMFR0_EL1);
807 	read_sysreg_case(SYS_ID_MMFR1_EL1);
808 	read_sysreg_case(SYS_ID_MMFR2_EL1);
809 	read_sysreg_case(SYS_ID_MMFR3_EL1);
810 	read_sysreg_case(SYS_ID_ISAR0_EL1);
811 	read_sysreg_case(SYS_ID_ISAR1_EL1);
812 	read_sysreg_case(SYS_ID_ISAR2_EL1);
813 	read_sysreg_case(SYS_ID_ISAR3_EL1);
814 	read_sysreg_case(SYS_ID_ISAR4_EL1);
815 	read_sysreg_case(SYS_ID_ISAR5_EL1);
816 	read_sysreg_case(SYS_MVFR0_EL1);
817 	read_sysreg_case(SYS_MVFR1_EL1);
818 	read_sysreg_case(SYS_MVFR2_EL1);
819 
820 	read_sysreg_case(SYS_ID_AA64PFR0_EL1);
821 	read_sysreg_case(SYS_ID_AA64PFR1_EL1);
822 	read_sysreg_case(SYS_ID_AA64ZFR0_EL1);
823 	read_sysreg_case(SYS_ID_AA64DFR0_EL1);
824 	read_sysreg_case(SYS_ID_AA64DFR1_EL1);
825 	read_sysreg_case(SYS_ID_AA64MMFR0_EL1);
826 	read_sysreg_case(SYS_ID_AA64MMFR1_EL1);
827 	read_sysreg_case(SYS_ID_AA64MMFR2_EL1);
828 	read_sysreg_case(SYS_ID_AA64ISAR0_EL1);
829 	read_sysreg_case(SYS_ID_AA64ISAR1_EL1);
830 
831 	read_sysreg_case(SYS_CNTFRQ_EL0);
832 	read_sysreg_case(SYS_CTR_EL0);
833 	read_sysreg_case(SYS_DCZID_EL0);
834 
835 	default:
836 		BUG();
837 		return 0;
838 	}
839 }
840 
841 #include <linux/irqchip/arm-gic-v3.h>
842 
843 static bool
844 feature_matches(u64 reg, const struct arm64_cpu_capabilities *entry)
845 {
846 	int val = cpuid_feature_extract_field(reg, entry->field_pos, entry->sign);
847 
848 	return val >= entry->min_field_value;
849 }
850 
851 static bool
852 has_cpuid_feature(const struct arm64_cpu_capabilities *entry, int scope)
853 {
854 	u64 val;
855 
856 	WARN_ON(scope == SCOPE_LOCAL_CPU && preemptible());
857 	if (scope == SCOPE_SYSTEM)
858 		val = read_sanitised_ftr_reg(entry->sys_reg);
859 	else
860 		val = __read_sysreg_by_encoding(entry->sys_reg);
861 
862 	return feature_matches(val, entry);
863 }
864 
865 static bool has_useable_gicv3_cpuif(const struct arm64_cpu_capabilities *entry, int scope)
866 {
867 	bool has_sre;
868 
869 	if (!has_cpuid_feature(entry, scope))
870 		return false;
871 
872 	has_sre = gic_enable_sre();
873 	if (!has_sre)
874 		pr_warn_once("%s present but disabled by higher exception level\n",
875 			     entry->desc);
876 
877 	return has_sre;
878 }
879 
880 static bool has_no_hw_prefetch(const struct arm64_cpu_capabilities *entry, int __unused)
881 {
882 	u32 midr = read_cpuid_id();
883 
884 	/* Cavium ThunderX pass 1.x and 2.x */
885 	return MIDR_IS_CPU_MODEL_RANGE(midr, MIDR_THUNDERX,
886 		MIDR_CPU_VAR_REV(0, 0),
887 		MIDR_CPU_VAR_REV(1, MIDR_REVISION_MASK));
888 }
889 
890 static bool has_no_fpsimd(const struct arm64_cpu_capabilities *entry, int __unused)
891 {
892 	u64 pfr0 = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);
893 
894 	return cpuid_feature_extract_signed_field(pfr0,
895 					ID_AA64PFR0_FP_SHIFT) < 0;
896 }
897 
898 static bool has_cache_idc(const struct arm64_cpu_capabilities *entry,
899 			  int scope)
900 {
901 	u64 ctr;
902 
903 	if (scope == SCOPE_SYSTEM)
904 		ctr = arm64_ftr_reg_ctrel0.sys_val;
905 	else
906 		ctr = read_cpuid_effective_cachetype();
907 
908 	return ctr & BIT(CTR_IDC_SHIFT);
909 }
910 
911 static void cpu_emulate_effective_ctr(const struct arm64_cpu_capabilities *__unused)
912 {
913 	/*
914 	 * If the CPU exposes raw CTR_EL0.IDC = 0, while effectively
915 	 * CTR_EL0.IDC = 1 (from CLIDR values), we need to trap accesses
916 	 * to the CTR_EL0 on this CPU and emulate it with the real/safe
917 	 * value.
918 	 */
919 	if (!(read_cpuid_cachetype() & BIT(CTR_IDC_SHIFT)))
920 		sysreg_clear_set(sctlr_el1, SCTLR_EL1_UCT, 0);
921 }
922 
923 static bool has_cache_dic(const struct arm64_cpu_capabilities *entry,
924 			  int scope)
925 {
926 	u64 ctr;
927 
928 	if (scope == SCOPE_SYSTEM)
929 		ctr = arm64_ftr_reg_ctrel0.sys_val;
930 	else
931 		ctr = read_cpuid_cachetype();
932 
933 	return ctr & BIT(CTR_DIC_SHIFT);
934 }
935 
936 static bool __maybe_unused
937 has_useable_cnp(const struct arm64_cpu_capabilities *entry, int scope)
938 {
939 	/*
940 	 * Kdump isn't guaranteed to power-off all secondary CPUs, CNP
941 	 * may share TLB entries with a CPU stuck in the crashed
942 	 * kernel.
943 	 */
944 	 if (is_kdump_kernel())
945 		return false;
946 
947 	return has_cpuid_feature(entry, scope);
948 }
949 
950 static bool __meltdown_safe = true;
951 static int __kpti_forced; /* 0: not forced, >0: forced on, <0: forced off */
952 
953 static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
954 				int scope)
955 {
956 	/* List of CPUs that are not vulnerable and don't need KPTI */
957 	static const struct midr_range kpti_safe_list[] = {
958 		MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2),
959 		MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
960 		MIDR_ALL_VERSIONS(MIDR_CORTEX_A35),
961 		MIDR_ALL_VERSIONS(MIDR_CORTEX_A53),
962 		MIDR_ALL_VERSIONS(MIDR_CORTEX_A55),
963 		MIDR_ALL_VERSIONS(MIDR_CORTEX_A57),
964 		MIDR_ALL_VERSIONS(MIDR_CORTEX_A72),
965 		MIDR_ALL_VERSIONS(MIDR_CORTEX_A73),
966 		MIDR_ALL_VERSIONS(MIDR_HISI_TSV110),
967 		{ /* sentinel */ }
968 	};
969 	char const *str = "kpti command line option";
970 	bool meltdown_safe;
971 
972 	meltdown_safe = is_midr_in_range_list(read_cpuid_id(), kpti_safe_list);
973 
974 	/* Defer to CPU feature registers */
975 	if (has_cpuid_feature(entry, scope))
976 		meltdown_safe = true;
977 
978 	if (!meltdown_safe)
979 		__meltdown_safe = false;
980 
981 	/*
982 	 * For reasons that aren't entirely clear, enabling KPTI on Cavium
983 	 * ThunderX leads to apparent I-cache corruption of kernel text, which
984 	 * ends as well as you might imagine. Don't even try.
985 	 */
986 	if (cpus_have_const_cap(ARM64_WORKAROUND_CAVIUM_27456)) {
987 		str = "ARM64_WORKAROUND_CAVIUM_27456";
988 		__kpti_forced = -1;
989 	}
990 
991 	/* Useful for KASLR robustness */
992 	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_offset() > 0) {
993 		if (!__kpti_forced) {
994 			str = "KASLR";
995 			__kpti_forced = 1;
996 		}
997 	}
998 
999 	if (cpu_mitigations_off() && !__kpti_forced) {
1000 		str = "mitigations=off";
1001 		__kpti_forced = -1;
1002 	}
1003 
1004 	if (!IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0)) {
1005 		pr_info_once("kernel page table isolation disabled by kernel configuration\n");
1006 		return false;
1007 	}
1008 
1009 	/* Forced? */
1010 	if (__kpti_forced) {
1011 		pr_info_once("kernel page table isolation forced %s by %s\n",
1012 			     __kpti_forced > 0 ? "ON" : "OFF", str);
1013 		return __kpti_forced > 0;
1014 	}
1015 
1016 	return !meltdown_safe;
1017 }
1018 
1019 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
1020 static void
1021 kpti_install_ng_mappings(const struct arm64_cpu_capabilities *__unused)
1022 {
1023 	typedef void (kpti_remap_fn)(int, int, phys_addr_t);
1024 	extern kpti_remap_fn idmap_kpti_install_ng_mappings;
1025 	kpti_remap_fn *remap_fn;
1026 
1027 	static bool kpti_applied = false;
1028 	int cpu = smp_processor_id();
1029 
1030 	/*
1031 	 * We don't need to rewrite the page-tables if either we've done
1032 	 * it already or we have KASLR enabled and therefore have not
1033 	 * created any global mappings at all.
1034 	 */
1035 	if (kpti_applied || kaslr_offset() > 0)
1036 		return;
1037 
1038 	remap_fn = (void *)__pa_symbol(idmap_kpti_install_ng_mappings);
1039 
1040 	cpu_install_idmap();
1041 	remap_fn(cpu, num_online_cpus(), __pa_symbol(swapper_pg_dir));
1042 	cpu_uninstall_idmap();
1043 
1044 	if (!cpu)
1045 		kpti_applied = true;
1046 
1047 	return;
1048 }
1049 #else
1050 static void
1051 kpti_install_ng_mappings(const struct arm64_cpu_capabilities *__unused)
1052 {
1053 }
1054 #endif	/* CONFIG_UNMAP_KERNEL_AT_EL0 */
1055 
1056 static int __init parse_kpti(char *str)
1057 {
1058 	bool enabled;
1059 	int ret = strtobool(str, &enabled);
1060 
1061 	if (ret)
1062 		return ret;
1063 
1064 	__kpti_forced = enabled ? 1 : -1;
1065 	return 0;
1066 }
1067 early_param("kpti", parse_kpti);
1068 
1069 #ifdef CONFIG_ARM64_HW_AFDBM
1070 static inline void __cpu_enable_hw_dbm(void)
1071 {
1072 	u64 tcr = read_sysreg(tcr_el1) | TCR_HD;
1073 
1074 	write_sysreg(tcr, tcr_el1);
1075 	isb();
1076 }
1077 
1078 static bool cpu_has_broken_dbm(void)
1079 {
1080 	/* List of CPUs which have broken DBM support. */
1081 	static const struct midr_range cpus[] = {
1082 #ifdef CONFIG_ARM64_ERRATUM_1024718
1083 		MIDR_RANGE(MIDR_CORTEX_A55, 0, 0, 1, 0),  // A55 r0p0 -r1p0
1084 #endif
1085 		{},
1086 	};
1087 
1088 	return is_midr_in_range_list(read_cpuid_id(), cpus);
1089 }
1090 
1091 static bool cpu_can_use_dbm(const struct arm64_cpu_capabilities *cap)
1092 {
1093 	return has_cpuid_feature(cap, SCOPE_LOCAL_CPU) &&
1094 	       !cpu_has_broken_dbm();
1095 }
1096 
1097 static void cpu_enable_hw_dbm(struct arm64_cpu_capabilities const *cap)
1098 {
1099 	if (cpu_can_use_dbm(cap))
1100 		__cpu_enable_hw_dbm();
1101 }
1102 
1103 static bool has_hw_dbm(const struct arm64_cpu_capabilities *cap,
1104 		       int __unused)
1105 {
1106 	static bool detected = false;
1107 	/*
1108 	 * DBM is a non-conflicting feature. i.e, the kernel can safely
1109 	 * run a mix of CPUs with and without the feature. So, we
1110 	 * unconditionally enable the capability to allow any late CPU
1111 	 * to use the feature. We only enable the control bits on the
1112 	 * CPU, if it actually supports.
1113 	 *
1114 	 * We have to make sure we print the "feature" detection only
1115 	 * when at least one CPU actually uses it. So check if this CPU
1116 	 * can actually use it and print the message exactly once.
1117 	 *
1118 	 * This is safe as all CPUs (including secondary CPUs - due to the
1119 	 * LOCAL_CPU scope - and the hotplugged CPUs - via verification)
1120 	 * goes through the "matches" check exactly once. Also if a CPU
1121 	 * matches the criteria, it is guaranteed that the CPU will turn
1122 	 * the DBM on, as the capability is unconditionally enabled.
1123 	 */
1124 	if (!detected && cpu_can_use_dbm(cap)) {
1125 		detected = true;
1126 		pr_info("detected: Hardware dirty bit management\n");
1127 	}
1128 
1129 	return true;
1130 }
1131 
1132 #endif
1133 
1134 #ifdef CONFIG_ARM64_VHE
1135 static bool runs_at_el2(const struct arm64_cpu_capabilities *entry, int __unused)
1136 {
1137 	return is_kernel_in_hyp_mode();
1138 }
1139 
1140 static void cpu_copy_el2regs(const struct arm64_cpu_capabilities *__unused)
1141 {
1142 	/*
1143 	 * Copy register values that aren't redirected by hardware.
1144 	 *
1145 	 * Before code patching, we only set tpidr_el1, all CPUs need to copy
1146 	 * this value to tpidr_el2 before we patch the code. Once we've done
1147 	 * that, freshly-onlined CPUs will set tpidr_el2, so we don't need to
1148 	 * do anything here.
1149 	 */
1150 	if (!alternative_is_applied(ARM64_HAS_VIRT_HOST_EXTN))
1151 		write_sysreg(read_sysreg(tpidr_el1), tpidr_el2);
1152 }
1153 #endif
1154 
1155 static void cpu_has_fwb(const struct arm64_cpu_capabilities *__unused)
1156 {
1157 	u64 val = read_sysreg_s(SYS_CLIDR_EL1);
1158 
1159 	/* Check that CLIDR_EL1.LOU{U,IS} are both 0 */
1160 	WARN_ON(val & (7 << 27 | 7 << 21));
1161 }
1162 
1163 #ifdef CONFIG_ARM64_SSBD
1164 static int ssbs_emulation_handler(struct pt_regs *regs, u32 instr)
1165 {
1166 	if (user_mode(regs))
1167 		return 1;
1168 
1169 	if (instr & BIT(PSTATE_Imm_shift))
1170 		regs->pstate |= PSR_SSBS_BIT;
1171 	else
1172 		regs->pstate &= ~PSR_SSBS_BIT;
1173 
1174 	arm64_skip_faulting_instruction(regs, 4);
1175 	return 0;
1176 }
1177 
1178 static struct undef_hook ssbs_emulation_hook = {
1179 	.instr_mask	= ~(1U << PSTATE_Imm_shift),
1180 	.instr_val	= 0xd500401f | PSTATE_SSBS,
1181 	.fn		= ssbs_emulation_handler,
1182 };
1183 
1184 static void cpu_enable_ssbs(const struct arm64_cpu_capabilities *__unused)
1185 {
1186 	static bool undef_hook_registered = false;
1187 	static DEFINE_RAW_SPINLOCK(hook_lock);
1188 
1189 	raw_spin_lock(&hook_lock);
1190 	if (!undef_hook_registered) {
1191 		register_undef_hook(&ssbs_emulation_hook);
1192 		undef_hook_registered = true;
1193 	}
1194 	raw_spin_unlock(&hook_lock);
1195 
1196 	if (arm64_get_ssbd_state() == ARM64_SSBD_FORCE_DISABLE) {
1197 		sysreg_clear_set(sctlr_el1, 0, SCTLR_ELx_DSSBS);
1198 		arm64_set_ssbd_mitigation(false);
1199 	} else {
1200 		arm64_set_ssbd_mitigation(true);
1201 	}
1202 }
1203 #endif /* CONFIG_ARM64_SSBD */
1204 
1205 #ifdef CONFIG_ARM64_PAN
1206 static void cpu_enable_pan(const struct arm64_cpu_capabilities *__unused)
1207 {
1208 	/*
1209 	 * We modify PSTATE. This won't work from irq context as the PSTATE
1210 	 * is discarded once we return from the exception.
1211 	 */
1212 	WARN_ON_ONCE(in_interrupt());
1213 
1214 	sysreg_clear_set(sctlr_el1, SCTLR_EL1_SPAN, 0);
1215 	asm(SET_PSTATE_PAN(1));
1216 }
1217 #endif /* CONFIG_ARM64_PAN */
1218 
1219 #ifdef CONFIG_ARM64_RAS_EXTN
1220 static void cpu_clear_disr(const struct arm64_cpu_capabilities *__unused)
1221 {
1222 	/* Firmware may have left a deferred SError in this register. */
1223 	write_sysreg_s(0, SYS_DISR_EL1);
1224 }
1225 #endif /* CONFIG_ARM64_RAS_EXTN */
1226 
1227 #ifdef CONFIG_ARM64_PTR_AUTH
1228 static void cpu_enable_address_auth(struct arm64_cpu_capabilities const *cap)
1229 {
1230 	sysreg_clear_set(sctlr_el1, 0, SCTLR_ELx_ENIA | SCTLR_ELx_ENIB |
1231 				       SCTLR_ELx_ENDA | SCTLR_ELx_ENDB);
1232 }
1233 #endif /* CONFIG_ARM64_PTR_AUTH */
1234 
1235 #ifdef CONFIG_ARM64_PSEUDO_NMI
1236 static bool enable_pseudo_nmi;
1237 
1238 static int __init early_enable_pseudo_nmi(char *p)
1239 {
1240 	return strtobool(p, &enable_pseudo_nmi);
1241 }
1242 early_param("irqchip.gicv3_pseudo_nmi", early_enable_pseudo_nmi);
1243 
1244 static bool can_use_gic_priorities(const struct arm64_cpu_capabilities *entry,
1245 				   int scope)
1246 {
1247 	return enable_pseudo_nmi && has_useable_gicv3_cpuif(entry, scope);
1248 }
1249 #endif
1250 
1251 static const struct arm64_cpu_capabilities arm64_features[] = {
1252 	{
1253 		.desc = "GIC system register CPU interface",
1254 		.capability = ARM64_HAS_SYSREG_GIC_CPUIF,
1255 		.type = ARM64_CPUCAP_STRICT_BOOT_CPU_FEATURE,
1256 		.matches = has_useable_gicv3_cpuif,
1257 		.sys_reg = SYS_ID_AA64PFR0_EL1,
1258 		.field_pos = ID_AA64PFR0_GIC_SHIFT,
1259 		.sign = FTR_UNSIGNED,
1260 		.min_field_value = 1,
1261 	},
1262 #ifdef CONFIG_ARM64_PAN
1263 	{
1264 		.desc = "Privileged Access Never",
1265 		.capability = ARM64_HAS_PAN,
1266 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1267 		.matches = has_cpuid_feature,
1268 		.sys_reg = SYS_ID_AA64MMFR1_EL1,
1269 		.field_pos = ID_AA64MMFR1_PAN_SHIFT,
1270 		.sign = FTR_UNSIGNED,
1271 		.min_field_value = 1,
1272 		.cpu_enable = cpu_enable_pan,
1273 	},
1274 #endif /* CONFIG_ARM64_PAN */
1275 #if defined(CONFIG_AS_LSE) && defined(CONFIG_ARM64_LSE_ATOMICS)
1276 	{
1277 		.desc = "LSE atomic instructions",
1278 		.capability = ARM64_HAS_LSE_ATOMICS,
1279 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1280 		.matches = has_cpuid_feature,
1281 		.sys_reg = SYS_ID_AA64ISAR0_EL1,
1282 		.field_pos = ID_AA64ISAR0_ATOMICS_SHIFT,
1283 		.sign = FTR_UNSIGNED,
1284 		.min_field_value = 2,
1285 	},
1286 #endif /* CONFIG_AS_LSE && CONFIG_ARM64_LSE_ATOMICS */
1287 	{
1288 		.desc = "Software prefetching using PRFM",
1289 		.capability = ARM64_HAS_NO_HW_PREFETCH,
1290 		.type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE,
1291 		.matches = has_no_hw_prefetch,
1292 	},
1293 #ifdef CONFIG_ARM64_UAO
1294 	{
1295 		.desc = "User Access Override",
1296 		.capability = ARM64_HAS_UAO,
1297 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1298 		.matches = has_cpuid_feature,
1299 		.sys_reg = SYS_ID_AA64MMFR2_EL1,
1300 		.field_pos = ID_AA64MMFR2_UAO_SHIFT,
1301 		.min_field_value = 1,
1302 		/*
1303 		 * We rely on stop_machine() calling uao_thread_switch() to set
1304 		 * UAO immediately after patching.
1305 		 */
1306 	},
1307 #endif /* CONFIG_ARM64_UAO */
1308 #ifdef CONFIG_ARM64_PAN
1309 	{
1310 		.capability = ARM64_ALT_PAN_NOT_UAO,
1311 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1312 		.matches = cpufeature_pan_not_uao,
1313 	},
1314 #endif /* CONFIG_ARM64_PAN */
1315 #ifdef CONFIG_ARM64_VHE
1316 	{
1317 		.desc = "Virtualization Host Extensions",
1318 		.capability = ARM64_HAS_VIRT_HOST_EXTN,
1319 		.type = ARM64_CPUCAP_STRICT_BOOT_CPU_FEATURE,
1320 		.matches = runs_at_el2,
1321 		.cpu_enable = cpu_copy_el2regs,
1322 	},
1323 #endif	/* CONFIG_ARM64_VHE */
1324 	{
1325 		.desc = "32-bit EL0 Support",
1326 		.capability = ARM64_HAS_32BIT_EL0,
1327 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1328 		.matches = has_cpuid_feature,
1329 		.sys_reg = SYS_ID_AA64PFR0_EL1,
1330 		.sign = FTR_UNSIGNED,
1331 		.field_pos = ID_AA64PFR0_EL0_SHIFT,
1332 		.min_field_value = ID_AA64PFR0_EL0_32BIT_64BIT,
1333 	},
1334 	{
1335 		.desc = "Kernel page table isolation (KPTI)",
1336 		.capability = ARM64_UNMAP_KERNEL_AT_EL0,
1337 		.type = ARM64_CPUCAP_BOOT_RESTRICTED_CPU_LOCAL_FEATURE,
1338 		/*
1339 		 * The ID feature fields below are used to indicate that
1340 		 * the CPU doesn't need KPTI. See unmap_kernel_at_el0 for
1341 		 * more details.
1342 		 */
1343 		.sys_reg = SYS_ID_AA64PFR0_EL1,
1344 		.field_pos = ID_AA64PFR0_CSV3_SHIFT,
1345 		.min_field_value = 1,
1346 		.matches = unmap_kernel_at_el0,
1347 		.cpu_enable = kpti_install_ng_mappings,
1348 	},
1349 	{
1350 		/* FP/SIMD is not implemented */
1351 		.capability = ARM64_HAS_NO_FPSIMD,
1352 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1353 		.min_field_value = 0,
1354 		.matches = has_no_fpsimd,
1355 	},
1356 #ifdef CONFIG_ARM64_PMEM
1357 	{
1358 		.desc = "Data cache clean to Point of Persistence",
1359 		.capability = ARM64_HAS_DCPOP,
1360 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1361 		.matches = has_cpuid_feature,
1362 		.sys_reg = SYS_ID_AA64ISAR1_EL1,
1363 		.field_pos = ID_AA64ISAR1_DPB_SHIFT,
1364 		.min_field_value = 1,
1365 	},
1366 	{
1367 		.desc = "Data cache clean to Point of Deep Persistence",
1368 		.capability = ARM64_HAS_DCPODP,
1369 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1370 		.matches = has_cpuid_feature,
1371 		.sys_reg = SYS_ID_AA64ISAR1_EL1,
1372 		.sign = FTR_UNSIGNED,
1373 		.field_pos = ID_AA64ISAR1_DPB_SHIFT,
1374 		.min_field_value = 2,
1375 	},
1376 #endif
1377 #ifdef CONFIG_ARM64_SVE
1378 	{
1379 		.desc = "Scalable Vector Extension",
1380 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1381 		.capability = ARM64_SVE,
1382 		.sys_reg = SYS_ID_AA64PFR0_EL1,
1383 		.sign = FTR_UNSIGNED,
1384 		.field_pos = ID_AA64PFR0_SVE_SHIFT,
1385 		.min_field_value = ID_AA64PFR0_SVE,
1386 		.matches = has_cpuid_feature,
1387 		.cpu_enable = sve_kernel_enable,
1388 	},
1389 #endif /* CONFIG_ARM64_SVE */
1390 #ifdef CONFIG_ARM64_RAS_EXTN
1391 	{
1392 		.desc = "RAS Extension Support",
1393 		.capability = ARM64_HAS_RAS_EXTN,
1394 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1395 		.matches = has_cpuid_feature,
1396 		.sys_reg = SYS_ID_AA64PFR0_EL1,
1397 		.sign = FTR_UNSIGNED,
1398 		.field_pos = ID_AA64PFR0_RAS_SHIFT,
1399 		.min_field_value = ID_AA64PFR0_RAS_V1,
1400 		.cpu_enable = cpu_clear_disr,
1401 	},
1402 #endif /* CONFIG_ARM64_RAS_EXTN */
1403 	{
1404 		.desc = "Data cache clean to the PoU not required for I/D coherence",
1405 		.capability = ARM64_HAS_CACHE_IDC,
1406 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1407 		.matches = has_cache_idc,
1408 		.cpu_enable = cpu_emulate_effective_ctr,
1409 	},
1410 	{
1411 		.desc = "Instruction cache invalidation not required for I/D coherence",
1412 		.capability = ARM64_HAS_CACHE_DIC,
1413 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1414 		.matches = has_cache_dic,
1415 	},
1416 	{
1417 		.desc = "Stage-2 Force Write-Back",
1418 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1419 		.capability = ARM64_HAS_STAGE2_FWB,
1420 		.sys_reg = SYS_ID_AA64MMFR2_EL1,
1421 		.sign = FTR_UNSIGNED,
1422 		.field_pos = ID_AA64MMFR2_FWB_SHIFT,
1423 		.min_field_value = 1,
1424 		.matches = has_cpuid_feature,
1425 		.cpu_enable = cpu_has_fwb,
1426 	},
1427 #ifdef CONFIG_ARM64_HW_AFDBM
1428 	{
1429 		/*
1430 		 * Since we turn this on always, we don't want the user to
1431 		 * think that the feature is available when it may not be.
1432 		 * So hide the description.
1433 		 *
1434 		 * .desc = "Hardware pagetable Dirty Bit Management",
1435 		 *
1436 		 */
1437 		.type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE,
1438 		.capability = ARM64_HW_DBM,
1439 		.sys_reg = SYS_ID_AA64MMFR1_EL1,
1440 		.sign = FTR_UNSIGNED,
1441 		.field_pos = ID_AA64MMFR1_HADBS_SHIFT,
1442 		.min_field_value = 2,
1443 		.matches = has_hw_dbm,
1444 		.cpu_enable = cpu_enable_hw_dbm,
1445 	},
1446 #endif
1447 	{
1448 		.desc = "CRC32 instructions",
1449 		.capability = ARM64_HAS_CRC32,
1450 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1451 		.matches = has_cpuid_feature,
1452 		.sys_reg = SYS_ID_AA64ISAR0_EL1,
1453 		.field_pos = ID_AA64ISAR0_CRC32_SHIFT,
1454 		.min_field_value = 1,
1455 	},
1456 #ifdef CONFIG_ARM64_SSBD
1457 	{
1458 		.desc = "Speculative Store Bypassing Safe (SSBS)",
1459 		.capability = ARM64_SSBS,
1460 		.type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE,
1461 		.matches = has_cpuid_feature,
1462 		.sys_reg = SYS_ID_AA64PFR1_EL1,
1463 		.field_pos = ID_AA64PFR1_SSBS_SHIFT,
1464 		.sign = FTR_UNSIGNED,
1465 		.min_field_value = ID_AA64PFR1_SSBS_PSTATE_ONLY,
1466 		.cpu_enable = cpu_enable_ssbs,
1467 	},
1468 #endif
1469 #ifdef CONFIG_ARM64_CNP
1470 	{
1471 		.desc = "Common not Private translations",
1472 		.capability = ARM64_HAS_CNP,
1473 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1474 		.matches = has_useable_cnp,
1475 		.sys_reg = SYS_ID_AA64MMFR2_EL1,
1476 		.sign = FTR_UNSIGNED,
1477 		.field_pos = ID_AA64MMFR2_CNP_SHIFT,
1478 		.min_field_value = 1,
1479 		.cpu_enable = cpu_enable_cnp,
1480 	},
1481 #endif
1482 	{
1483 		.desc = "Speculation barrier (SB)",
1484 		.capability = ARM64_HAS_SB,
1485 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1486 		.matches = has_cpuid_feature,
1487 		.sys_reg = SYS_ID_AA64ISAR1_EL1,
1488 		.field_pos = ID_AA64ISAR1_SB_SHIFT,
1489 		.sign = FTR_UNSIGNED,
1490 		.min_field_value = 1,
1491 	},
1492 #ifdef CONFIG_ARM64_PTR_AUTH
1493 	{
1494 		.desc = "Address authentication (architected algorithm)",
1495 		.capability = ARM64_HAS_ADDRESS_AUTH_ARCH,
1496 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1497 		.sys_reg = SYS_ID_AA64ISAR1_EL1,
1498 		.sign = FTR_UNSIGNED,
1499 		.field_pos = ID_AA64ISAR1_APA_SHIFT,
1500 		.min_field_value = ID_AA64ISAR1_APA_ARCHITECTED,
1501 		.matches = has_cpuid_feature,
1502 		.cpu_enable = cpu_enable_address_auth,
1503 	},
1504 	{
1505 		.desc = "Address authentication (IMP DEF algorithm)",
1506 		.capability = ARM64_HAS_ADDRESS_AUTH_IMP_DEF,
1507 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1508 		.sys_reg = SYS_ID_AA64ISAR1_EL1,
1509 		.sign = FTR_UNSIGNED,
1510 		.field_pos = ID_AA64ISAR1_API_SHIFT,
1511 		.min_field_value = ID_AA64ISAR1_API_IMP_DEF,
1512 		.matches = has_cpuid_feature,
1513 		.cpu_enable = cpu_enable_address_auth,
1514 	},
1515 	{
1516 		.desc = "Generic authentication (architected algorithm)",
1517 		.capability = ARM64_HAS_GENERIC_AUTH_ARCH,
1518 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1519 		.sys_reg = SYS_ID_AA64ISAR1_EL1,
1520 		.sign = FTR_UNSIGNED,
1521 		.field_pos = ID_AA64ISAR1_GPA_SHIFT,
1522 		.min_field_value = ID_AA64ISAR1_GPA_ARCHITECTED,
1523 		.matches = has_cpuid_feature,
1524 	},
1525 	{
1526 		.desc = "Generic authentication (IMP DEF algorithm)",
1527 		.capability = ARM64_HAS_GENERIC_AUTH_IMP_DEF,
1528 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
1529 		.sys_reg = SYS_ID_AA64ISAR1_EL1,
1530 		.sign = FTR_UNSIGNED,
1531 		.field_pos = ID_AA64ISAR1_GPI_SHIFT,
1532 		.min_field_value = ID_AA64ISAR1_GPI_IMP_DEF,
1533 		.matches = has_cpuid_feature,
1534 	},
1535 #endif /* CONFIG_ARM64_PTR_AUTH */
1536 #ifdef CONFIG_ARM64_PSEUDO_NMI
1537 	{
1538 		/*
1539 		 * Depends on having GICv3
1540 		 */
1541 		.desc = "IRQ priority masking",
1542 		.capability = ARM64_HAS_IRQ_PRIO_MASKING,
1543 		.type = ARM64_CPUCAP_STRICT_BOOT_CPU_FEATURE,
1544 		.matches = can_use_gic_priorities,
1545 		.sys_reg = SYS_ID_AA64PFR0_EL1,
1546 		.field_pos = ID_AA64PFR0_GIC_SHIFT,
1547 		.sign = FTR_UNSIGNED,
1548 		.min_field_value = 1,
1549 	},
1550 #endif
1551 	{},
1552 };
1553 
1554 #define HWCAP_CPUID_MATCH(reg, field, s, min_value)				\
1555 		.matches = has_cpuid_feature,					\
1556 		.sys_reg = reg,							\
1557 		.field_pos = field,						\
1558 		.sign = s,							\
1559 		.min_field_value = min_value,
1560 
1561 #define __HWCAP_CAP(name, cap_type, cap)					\
1562 		.desc = name,							\
1563 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,				\
1564 		.hwcap_type = cap_type,						\
1565 		.hwcap = cap,							\
1566 
1567 #define HWCAP_CAP(reg, field, s, min_value, cap_type, cap)			\
1568 	{									\
1569 		__HWCAP_CAP(#cap, cap_type, cap)				\
1570 		HWCAP_CPUID_MATCH(reg, field, s, min_value)			\
1571 	}
1572 
1573 #define HWCAP_MULTI_CAP(list, cap_type, cap)					\
1574 	{									\
1575 		__HWCAP_CAP(#cap, cap_type, cap)				\
1576 		.matches = cpucap_multi_entry_cap_matches,			\
1577 		.match_list = list,						\
1578 	}
1579 
1580 #ifdef CONFIG_ARM64_PTR_AUTH
1581 static const struct arm64_cpu_capabilities ptr_auth_hwcap_addr_matches[] = {
1582 	{
1583 		HWCAP_CPUID_MATCH(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_APA_SHIFT,
1584 				  FTR_UNSIGNED, ID_AA64ISAR1_APA_ARCHITECTED)
1585 	},
1586 	{
1587 		HWCAP_CPUID_MATCH(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_API_SHIFT,
1588 				  FTR_UNSIGNED, ID_AA64ISAR1_API_IMP_DEF)
1589 	},
1590 	{},
1591 };
1592 
1593 static const struct arm64_cpu_capabilities ptr_auth_hwcap_gen_matches[] = {
1594 	{
1595 		HWCAP_CPUID_MATCH(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_GPA_SHIFT,
1596 				  FTR_UNSIGNED, ID_AA64ISAR1_GPA_ARCHITECTED)
1597 	},
1598 	{
1599 		HWCAP_CPUID_MATCH(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_GPI_SHIFT,
1600 				  FTR_UNSIGNED, ID_AA64ISAR1_GPI_IMP_DEF)
1601 	},
1602 	{},
1603 };
1604 #endif
1605 
1606 static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
1607 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_AES_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, KERNEL_HWCAP_PMULL),
1608 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_AES_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_AES),
1609 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA1_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_SHA1),
1610 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA2_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_SHA2),
1611 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA2_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, KERNEL_HWCAP_SHA512),
1612 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_CRC32_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_CRC32),
1613 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_ATOMICS_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, KERNEL_HWCAP_ATOMICS),
1614 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_RDM_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_ASIMDRDM),
1615 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA3_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_SHA3),
1616 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SM3_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_SM3),
1617 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SM4_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_SM4),
1618 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_DP_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_ASIMDDP),
1619 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_FHM_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_ASIMDFHM),
1620 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_TS_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_FLAGM),
1621 	HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_TS_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, KERNEL_HWCAP_FLAGM2),
1622 	HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_FP_SHIFT, FTR_SIGNED, 0, CAP_HWCAP, KERNEL_HWCAP_FP),
1623 	HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_FP_SHIFT, FTR_SIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_FPHP),
1624 	HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_ASIMD_SHIFT, FTR_SIGNED, 0, CAP_HWCAP, KERNEL_HWCAP_ASIMD),
1625 	HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_ASIMD_SHIFT, FTR_SIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_ASIMDHP),
1626 	HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_DIT_SHIFT, FTR_SIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_DIT),
1627 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_DPB_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_DCPOP),
1628 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_DPB_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, KERNEL_HWCAP_DCPODP),
1629 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_JSCVT_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_JSCVT),
1630 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_FCMA_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_FCMA),
1631 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_LRCPC_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_LRCPC),
1632 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_LRCPC_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, KERNEL_HWCAP_ILRCPC),
1633 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_FRINTTS_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_FRINT),
1634 	HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_SB_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_SB),
1635 	HWCAP_CAP(SYS_ID_AA64MMFR2_EL1, ID_AA64MMFR2_AT_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_USCAT),
1636 #ifdef CONFIG_ARM64_SVE
1637 	HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_SVE_SHIFT, FTR_UNSIGNED, ID_AA64PFR0_SVE, CAP_HWCAP, KERNEL_HWCAP_SVE),
1638 	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_SVEVER_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_SVEVER_SVE2, CAP_HWCAP, KERNEL_HWCAP_SVE2),
1639 	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_AES_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_AES, CAP_HWCAP, KERNEL_HWCAP_SVEAES),
1640 	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_AES_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_AES_PMULL, CAP_HWCAP, KERNEL_HWCAP_SVEPMULL),
1641 	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_BITPERM_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_BITPERM, CAP_HWCAP, KERNEL_HWCAP_SVEBITPERM),
1642 	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_SHA3_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_SHA3, CAP_HWCAP, KERNEL_HWCAP_SVESHA3),
1643 	HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_SM4_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_SM4, CAP_HWCAP, KERNEL_HWCAP_SVESM4),
1644 #endif
1645 	HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_SSBS_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_SSBS_PSTATE_INSNS, CAP_HWCAP, KERNEL_HWCAP_SSBS),
1646 #ifdef CONFIG_ARM64_PTR_AUTH
1647 	HWCAP_MULTI_CAP(ptr_auth_hwcap_addr_matches, CAP_HWCAP, KERNEL_HWCAP_PACA),
1648 	HWCAP_MULTI_CAP(ptr_auth_hwcap_gen_matches, CAP_HWCAP, KERNEL_HWCAP_PACG),
1649 #endif
1650 	{},
1651 };
1652 
1653 static const struct arm64_cpu_capabilities compat_elf_hwcaps[] = {
1654 #ifdef CONFIG_COMPAT
1655 	HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_AES_SHIFT, FTR_UNSIGNED, 2, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_PMULL),
1656 	HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_AES_SHIFT, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_AES),
1657 	HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_SHA1_SHIFT, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_SHA1),
1658 	HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_SHA2_SHIFT, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_SHA2),
1659 	HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_CRC32_SHIFT, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_CRC32),
1660 #endif
1661 	{},
1662 };
1663 
1664 static void __init cap_set_elf_hwcap(const struct arm64_cpu_capabilities *cap)
1665 {
1666 	switch (cap->hwcap_type) {
1667 	case CAP_HWCAP:
1668 		cpu_set_feature(cap->hwcap);
1669 		break;
1670 #ifdef CONFIG_COMPAT
1671 	case CAP_COMPAT_HWCAP:
1672 		compat_elf_hwcap |= (u32)cap->hwcap;
1673 		break;
1674 	case CAP_COMPAT_HWCAP2:
1675 		compat_elf_hwcap2 |= (u32)cap->hwcap;
1676 		break;
1677 #endif
1678 	default:
1679 		WARN_ON(1);
1680 		break;
1681 	}
1682 }
1683 
1684 /* Check if we have a particular HWCAP enabled */
1685 static bool cpus_have_elf_hwcap(const struct arm64_cpu_capabilities *cap)
1686 {
1687 	bool rc;
1688 
1689 	switch (cap->hwcap_type) {
1690 	case CAP_HWCAP:
1691 		rc = cpu_have_feature(cap->hwcap);
1692 		break;
1693 #ifdef CONFIG_COMPAT
1694 	case CAP_COMPAT_HWCAP:
1695 		rc = (compat_elf_hwcap & (u32)cap->hwcap) != 0;
1696 		break;
1697 	case CAP_COMPAT_HWCAP2:
1698 		rc = (compat_elf_hwcap2 & (u32)cap->hwcap) != 0;
1699 		break;
1700 #endif
1701 	default:
1702 		WARN_ON(1);
1703 		rc = false;
1704 	}
1705 
1706 	return rc;
1707 }
1708 
1709 static void __init setup_elf_hwcaps(const struct arm64_cpu_capabilities *hwcaps)
1710 {
1711 	/* We support emulation of accesses to CPU ID feature registers */
1712 	cpu_set_named_feature(CPUID);
1713 	for (; hwcaps->matches; hwcaps++)
1714 		if (hwcaps->matches(hwcaps, cpucap_default_scope(hwcaps)))
1715 			cap_set_elf_hwcap(hwcaps);
1716 }
1717 
1718 static void update_cpu_capabilities(u16 scope_mask)
1719 {
1720 	int i;
1721 	const struct arm64_cpu_capabilities *caps;
1722 
1723 	scope_mask &= ARM64_CPUCAP_SCOPE_MASK;
1724 	for (i = 0; i < ARM64_NCAPS; i++) {
1725 		caps = cpu_hwcaps_ptrs[i];
1726 		if (!caps || !(caps->type & scope_mask) ||
1727 		    cpus_have_cap(caps->capability) ||
1728 		    !caps->matches(caps, cpucap_default_scope(caps)))
1729 			continue;
1730 
1731 		if (caps->desc)
1732 			pr_info("detected: %s\n", caps->desc);
1733 		cpus_set_cap(caps->capability);
1734 
1735 		if ((scope_mask & SCOPE_BOOT_CPU) && (caps->type & SCOPE_BOOT_CPU))
1736 			set_bit(caps->capability, boot_capabilities);
1737 	}
1738 }
1739 
1740 /*
1741  * Enable all the available capabilities on this CPU. The capabilities
1742  * with BOOT_CPU scope are handled separately and hence skipped here.
1743  */
1744 static int cpu_enable_non_boot_scope_capabilities(void *__unused)
1745 {
1746 	int i;
1747 	u16 non_boot_scope = SCOPE_ALL & ~SCOPE_BOOT_CPU;
1748 
1749 	for_each_available_cap(i) {
1750 		const struct arm64_cpu_capabilities *cap = cpu_hwcaps_ptrs[i];
1751 
1752 		if (WARN_ON(!cap))
1753 			continue;
1754 
1755 		if (!(cap->type & non_boot_scope))
1756 			continue;
1757 
1758 		if (cap->cpu_enable)
1759 			cap->cpu_enable(cap);
1760 	}
1761 	return 0;
1762 }
1763 
1764 /*
1765  * Run through the enabled capabilities and enable() it on all active
1766  * CPUs
1767  */
1768 static void __init enable_cpu_capabilities(u16 scope_mask)
1769 {
1770 	int i;
1771 	const struct arm64_cpu_capabilities *caps;
1772 	bool boot_scope;
1773 
1774 	scope_mask &= ARM64_CPUCAP_SCOPE_MASK;
1775 	boot_scope = !!(scope_mask & SCOPE_BOOT_CPU);
1776 
1777 	for (i = 0; i < ARM64_NCAPS; i++) {
1778 		unsigned int num;
1779 
1780 		caps = cpu_hwcaps_ptrs[i];
1781 		if (!caps || !(caps->type & scope_mask))
1782 			continue;
1783 		num = caps->capability;
1784 		if (!cpus_have_cap(num))
1785 			continue;
1786 
1787 		/* Ensure cpus_have_const_cap(num) works */
1788 		static_branch_enable(&cpu_hwcap_keys[num]);
1789 
1790 		if (boot_scope && caps->cpu_enable)
1791 			/*
1792 			 * Capabilities with SCOPE_BOOT_CPU scope are finalised
1793 			 * before any secondary CPU boots. Thus, each secondary
1794 			 * will enable the capability as appropriate via
1795 			 * check_local_cpu_capabilities(). The only exception is
1796 			 * the boot CPU, for which the capability must be
1797 			 * enabled here. This approach avoids costly
1798 			 * stop_machine() calls for this case.
1799 			 */
1800 			caps->cpu_enable(caps);
1801 	}
1802 
1803 	/*
1804 	 * For all non-boot scope capabilities, use stop_machine()
1805 	 * as it schedules the work allowing us to modify PSTATE,
1806 	 * instead of on_each_cpu() which uses an IPI, giving us a
1807 	 * PSTATE that disappears when we return.
1808 	 */
1809 	if (!boot_scope)
1810 		stop_machine(cpu_enable_non_boot_scope_capabilities,
1811 			     NULL, cpu_online_mask);
1812 }
1813 
1814 /*
1815  * Run through the list of capabilities to check for conflicts.
1816  * If the system has already detected a capability, take necessary
1817  * action on this CPU.
1818  *
1819  * Returns "false" on conflicts.
1820  */
1821 static bool verify_local_cpu_caps(u16 scope_mask)
1822 {
1823 	int i;
1824 	bool cpu_has_cap, system_has_cap;
1825 	const struct arm64_cpu_capabilities *caps;
1826 
1827 	scope_mask &= ARM64_CPUCAP_SCOPE_MASK;
1828 
1829 	for (i = 0; i < ARM64_NCAPS; i++) {
1830 		caps = cpu_hwcaps_ptrs[i];
1831 		if (!caps || !(caps->type & scope_mask))
1832 			continue;
1833 
1834 		cpu_has_cap = caps->matches(caps, SCOPE_LOCAL_CPU);
1835 		system_has_cap = cpus_have_cap(caps->capability);
1836 
1837 		if (system_has_cap) {
1838 			/*
1839 			 * Check if the new CPU misses an advertised feature,
1840 			 * which is not safe to miss.
1841 			 */
1842 			if (!cpu_has_cap && !cpucap_late_cpu_optional(caps))
1843 				break;
1844 			/*
1845 			 * We have to issue cpu_enable() irrespective of
1846 			 * whether the CPU has it or not, as it is enabeld
1847 			 * system wide. It is upto the call back to take
1848 			 * appropriate action on this CPU.
1849 			 */
1850 			if (caps->cpu_enable)
1851 				caps->cpu_enable(caps);
1852 		} else {
1853 			/*
1854 			 * Check if the CPU has this capability if it isn't
1855 			 * safe to have when the system doesn't.
1856 			 */
1857 			if (cpu_has_cap && !cpucap_late_cpu_permitted(caps))
1858 				break;
1859 		}
1860 	}
1861 
1862 	if (i < ARM64_NCAPS) {
1863 		pr_crit("CPU%d: Detected conflict for capability %d (%s), System: %d, CPU: %d\n",
1864 			smp_processor_id(), caps->capability,
1865 			caps->desc, system_has_cap, cpu_has_cap);
1866 		return false;
1867 	}
1868 
1869 	return true;
1870 }
1871 
1872 /*
1873  * Check for CPU features that are used in early boot
1874  * based on the Boot CPU value.
1875  */
1876 static void check_early_cpu_features(void)
1877 {
1878 	verify_cpu_asid_bits();
1879 	/*
1880 	 * Early features are used by the kernel already. If there
1881 	 * is a conflict, we cannot proceed further.
1882 	 */
1883 	if (!verify_local_cpu_caps(SCOPE_BOOT_CPU))
1884 		cpu_panic_kernel();
1885 }
1886 
1887 static void
1888 verify_local_elf_hwcaps(const struct arm64_cpu_capabilities *caps)
1889 {
1890 
1891 	for (; caps->matches; caps++)
1892 		if (cpus_have_elf_hwcap(caps) && !caps->matches(caps, SCOPE_LOCAL_CPU)) {
1893 			pr_crit("CPU%d: missing HWCAP: %s\n",
1894 					smp_processor_id(), caps->desc);
1895 			cpu_die_early();
1896 		}
1897 }
1898 
1899 static void verify_sve_features(void)
1900 {
1901 	u64 safe_zcr = read_sanitised_ftr_reg(SYS_ZCR_EL1);
1902 	u64 zcr = read_zcr_features();
1903 
1904 	unsigned int safe_len = safe_zcr & ZCR_ELx_LEN_MASK;
1905 	unsigned int len = zcr & ZCR_ELx_LEN_MASK;
1906 
1907 	if (len < safe_len || sve_verify_vq_map()) {
1908 		pr_crit("CPU%d: SVE: vector length support mismatch\n",
1909 			smp_processor_id());
1910 		cpu_die_early();
1911 	}
1912 
1913 	/* Add checks on other ZCR bits here if necessary */
1914 }
1915 
1916 
1917 /*
1918  * Run through the enabled system capabilities and enable() it on this CPU.
1919  * The capabilities were decided based on the available CPUs at the boot time.
1920  * Any new CPU should match the system wide status of the capability. If the
1921  * new CPU doesn't have a capability which the system now has enabled, we
1922  * cannot do anything to fix it up and could cause unexpected failures. So
1923  * we park the CPU.
1924  */
1925 static void verify_local_cpu_capabilities(void)
1926 {
1927 	/*
1928 	 * The capabilities with SCOPE_BOOT_CPU are checked from
1929 	 * check_early_cpu_features(), as they need to be verified
1930 	 * on all secondary CPUs.
1931 	 */
1932 	if (!verify_local_cpu_caps(SCOPE_ALL & ~SCOPE_BOOT_CPU))
1933 		cpu_die_early();
1934 
1935 	verify_local_elf_hwcaps(arm64_elf_hwcaps);
1936 
1937 	if (system_supports_32bit_el0())
1938 		verify_local_elf_hwcaps(compat_elf_hwcaps);
1939 
1940 	if (system_supports_sve())
1941 		verify_sve_features();
1942 }
1943 
1944 void check_local_cpu_capabilities(void)
1945 {
1946 	/*
1947 	 * All secondary CPUs should conform to the early CPU features
1948 	 * in use by the kernel based on boot CPU.
1949 	 */
1950 	check_early_cpu_features();
1951 
1952 	/*
1953 	 * If we haven't finalised the system capabilities, this CPU gets
1954 	 * a chance to update the errata work arounds and local features.
1955 	 * Otherwise, this CPU should verify that it has all the system
1956 	 * advertised capabilities.
1957 	 */
1958 	if (!sys_caps_initialised)
1959 		update_cpu_capabilities(SCOPE_LOCAL_CPU);
1960 	else
1961 		verify_local_cpu_capabilities();
1962 }
1963 
1964 static void __init setup_boot_cpu_capabilities(void)
1965 {
1966 	/* Detect capabilities with either SCOPE_BOOT_CPU or SCOPE_LOCAL_CPU */
1967 	update_cpu_capabilities(SCOPE_BOOT_CPU | SCOPE_LOCAL_CPU);
1968 	/* Enable the SCOPE_BOOT_CPU capabilities alone right away */
1969 	enable_cpu_capabilities(SCOPE_BOOT_CPU);
1970 }
1971 
1972 DEFINE_STATIC_KEY_FALSE(arm64_const_caps_ready);
1973 EXPORT_SYMBOL(arm64_const_caps_ready);
1974 
1975 static void __init mark_const_caps_ready(void)
1976 {
1977 	static_branch_enable(&arm64_const_caps_ready);
1978 }
1979 
1980 bool this_cpu_has_cap(unsigned int n)
1981 {
1982 	if (!WARN_ON(preemptible()) && n < ARM64_NCAPS) {
1983 		const struct arm64_cpu_capabilities *cap = cpu_hwcaps_ptrs[n];
1984 
1985 		if (cap)
1986 			return cap->matches(cap, SCOPE_LOCAL_CPU);
1987 	}
1988 
1989 	return false;
1990 }
1991 
1992 void cpu_set_feature(unsigned int num)
1993 {
1994 	WARN_ON(num >= MAX_CPU_FEATURES);
1995 	elf_hwcap |= BIT(num);
1996 }
1997 EXPORT_SYMBOL_GPL(cpu_set_feature);
1998 
1999 bool cpu_have_feature(unsigned int num)
2000 {
2001 	WARN_ON(num >= MAX_CPU_FEATURES);
2002 	return elf_hwcap & BIT(num);
2003 }
2004 EXPORT_SYMBOL_GPL(cpu_have_feature);
2005 
2006 unsigned long cpu_get_elf_hwcap(void)
2007 {
2008 	/*
2009 	 * We currently only populate the first 32 bits of AT_HWCAP. Please
2010 	 * note that for userspace compatibility we guarantee that bits 62
2011 	 * and 63 will always be returned as 0.
2012 	 */
2013 	return lower_32_bits(elf_hwcap);
2014 }
2015 
2016 unsigned long cpu_get_elf_hwcap2(void)
2017 {
2018 	return upper_32_bits(elf_hwcap);
2019 }
2020 
2021 static void __init setup_system_capabilities(void)
2022 {
2023 	/*
2024 	 * We have finalised the system-wide safe feature
2025 	 * registers, finalise the capabilities that depend
2026 	 * on it. Also enable all the available capabilities,
2027 	 * that are not enabled already.
2028 	 */
2029 	update_cpu_capabilities(SCOPE_SYSTEM);
2030 	enable_cpu_capabilities(SCOPE_ALL & ~SCOPE_BOOT_CPU);
2031 }
2032 
2033 void __init setup_cpu_features(void)
2034 {
2035 	u32 cwg;
2036 
2037 	setup_system_capabilities();
2038 	mark_const_caps_ready();
2039 	setup_elf_hwcaps(arm64_elf_hwcaps);
2040 
2041 	if (system_supports_32bit_el0())
2042 		setup_elf_hwcaps(compat_elf_hwcaps);
2043 
2044 	if (system_uses_ttbr0_pan())
2045 		pr_info("emulated: Privileged Access Never (PAN) using TTBR0_EL1 switching\n");
2046 
2047 	sve_setup();
2048 	minsigstksz_setup();
2049 
2050 	/* Advertise that we have computed the system capabilities */
2051 	set_sys_caps_initialised();
2052 
2053 	/*
2054 	 * Check for sane CTR_EL0.CWG value.
2055 	 */
2056 	cwg = cache_type_cwg();
2057 	if (!cwg)
2058 		pr_warn("No Cache Writeback Granule information, assuming %d\n",
2059 			ARCH_DMA_MINALIGN);
2060 }
2061 
2062 static bool __maybe_unused
2063 cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused)
2064 {
2065 	return (cpus_have_const_cap(ARM64_HAS_PAN) && !cpus_have_const_cap(ARM64_HAS_UAO));
2066 }
2067 
2068 static void __maybe_unused cpu_enable_cnp(struct arm64_cpu_capabilities const *cap)
2069 {
2070 	cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
2071 }
2072 
2073 /*
2074  * We emulate only the following system register space.
2075  * Op0 = 0x3, CRn = 0x0, Op1 = 0x0, CRm = [0, 4 - 7]
2076  * See Table C5-6 System instruction encodings for System register accesses,
2077  * ARMv8 ARM(ARM DDI 0487A.f) for more details.
2078  */
2079 static inline bool __attribute_const__ is_emulated(u32 id)
2080 {
2081 	return (sys_reg_Op0(id) == 0x3 &&
2082 		sys_reg_CRn(id) == 0x0 &&
2083 		sys_reg_Op1(id) == 0x0 &&
2084 		(sys_reg_CRm(id) == 0 ||
2085 		 ((sys_reg_CRm(id) >= 4) && (sys_reg_CRm(id) <= 7))));
2086 }
2087 
2088 /*
2089  * With CRm == 0, reg should be one of :
2090  * MIDR_EL1, MPIDR_EL1 or REVIDR_EL1.
2091  */
2092 static inline int emulate_id_reg(u32 id, u64 *valp)
2093 {
2094 	switch (id) {
2095 	case SYS_MIDR_EL1:
2096 		*valp = read_cpuid_id();
2097 		break;
2098 	case SYS_MPIDR_EL1:
2099 		*valp = SYS_MPIDR_SAFE_VAL;
2100 		break;
2101 	case SYS_REVIDR_EL1:
2102 		/* IMPLEMENTATION DEFINED values are emulated with 0 */
2103 		*valp = 0;
2104 		break;
2105 	default:
2106 		return -EINVAL;
2107 	}
2108 
2109 	return 0;
2110 }
2111 
2112 static int emulate_sys_reg(u32 id, u64 *valp)
2113 {
2114 	struct arm64_ftr_reg *regp;
2115 
2116 	if (!is_emulated(id))
2117 		return -EINVAL;
2118 
2119 	if (sys_reg_CRm(id) == 0)
2120 		return emulate_id_reg(id, valp);
2121 
2122 	regp = get_arm64_ftr_reg(id);
2123 	if (regp)
2124 		*valp = arm64_ftr_reg_user_value(regp);
2125 	else
2126 		/*
2127 		 * The untracked registers are either IMPLEMENTATION DEFINED
2128 		 * (e.g, ID_AFR0_EL1) or reserved RAZ.
2129 		 */
2130 		*valp = 0;
2131 	return 0;
2132 }
2133 
2134 int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt)
2135 {
2136 	int rc;
2137 	u64 val;
2138 
2139 	rc = emulate_sys_reg(sys_reg, &val);
2140 	if (!rc) {
2141 		pt_regs_write_reg(regs, rt, val);
2142 		arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
2143 	}
2144 	return rc;
2145 }
2146 
2147 static int emulate_mrs(struct pt_regs *regs, u32 insn)
2148 {
2149 	u32 sys_reg, rt;
2150 
2151 	/*
2152 	 * sys_reg values are defined as used in mrs/msr instruction.
2153 	 * shift the imm value to get the encoding.
2154 	 */
2155 	sys_reg = (u32)aarch64_insn_decode_immediate(AARCH64_INSN_IMM_16, insn) << 5;
2156 	rt = aarch64_insn_decode_register(AARCH64_INSN_REGTYPE_RT, insn);
2157 	return do_emulate_mrs(regs, sys_reg, rt);
2158 }
2159 
2160 static struct undef_hook mrs_hook = {
2161 	.instr_mask = 0xfff00000,
2162 	.instr_val  = 0xd5300000,
2163 	.pstate_mask = PSR_AA32_MODE_MASK,
2164 	.pstate_val = PSR_MODE_EL0t,
2165 	.fn = emulate_mrs,
2166 };
2167 
2168 static int __init enable_mrs_emulation(void)
2169 {
2170 	register_undef_hook(&mrs_hook);
2171 	return 0;
2172 }
2173 
2174 core_initcall(enable_mrs_emulation);
2175 
2176 ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr,
2177 			  char *buf)
2178 {
2179 	if (__meltdown_safe)
2180 		return sprintf(buf, "Not affected\n");
2181 
2182 	if (arm64_kernel_unmapped_at_el0())
2183 		return sprintf(buf, "Mitigation: PTI\n");
2184 
2185 	return sprintf(buf, "Vulnerable\n");
2186 }
2187