2 * Contains CPU feature definitions
4 * Copyright (C) 2015 ARM Ltd.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
19 #define pr_fmt(fmt) "CPU features: " fmt
21 #include <linux/bsearch.h>
22 #include <linux/cpumask.h>
23 #include <linux/sort.h>
24 #include <linux/stop_machine.h>
25 #include <linux/types.h>
28 #include <asm/cpufeature.h>
29 #include <asm/cpu_ops.h>
30 #include <asm/fpsimd.h>
31 #include <asm/mmu_context.h>
32 #include <asm/processor.h>
33 #include <asm/sysreg.h>
34 #include <asm/traps.h>
37 unsigned long elf_hwcap __read_mostly;
38 EXPORT_SYMBOL_GPL(elf_hwcap);
41 #define COMPAT_ELF_HWCAP_DEFAULT \
42 (COMPAT_HWCAP_HALF|COMPAT_HWCAP_THUMB|\
43 COMPAT_HWCAP_FAST_MULT|COMPAT_HWCAP_EDSP|\
44 COMPAT_HWCAP_TLS|COMPAT_HWCAP_VFP|\
45 COMPAT_HWCAP_VFPv3|COMPAT_HWCAP_VFPv4|\
46 COMPAT_HWCAP_NEON|COMPAT_HWCAP_IDIV|\
48 unsigned int compat_elf_hwcap __read_mostly = COMPAT_ELF_HWCAP_DEFAULT;
49 unsigned int compat_elf_hwcap2 __read_mostly;
52 DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
53 EXPORT_SYMBOL(cpu_hwcaps);
56 * Flag to indicate if we have computed the system wide
57 * capabilities based on the boot time active CPUs. This
58 * will be used to determine if a new booting CPU should
59 * go through the verification process to make sure that it
60 * supports the system capabilities, without using a hotplug
63 static bool sys_caps_initialised;
65 static inline void set_sys_caps_initialised(void)
67 sys_caps_initialised = true;
70 static int dump_cpu_hwcaps(struct notifier_block *self, unsigned long v, void *p)
72 /* file-wide pr_fmt adds "CPU features: " prefix */
73 pr_emerg("0x%*pb\n", ARM64_NCAPS, &cpu_hwcaps);
77 static struct notifier_block cpu_hwcaps_notifier = {
78 .notifier_call = dump_cpu_hwcaps
81 static int __init register_cpu_hwcaps_dumper(void)
83 atomic_notifier_chain_register(&panic_notifier_list,
84 &cpu_hwcaps_notifier);
87 __initcall(register_cpu_hwcaps_dumper);
89 DEFINE_STATIC_KEY_ARRAY_FALSE(cpu_hwcap_keys, ARM64_NCAPS);
90 EXPORT_SYMBOL(cpu_hwcap_keys);
92 #define __ARM64_FTR_BITS(SIGNED, VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL) \
100 .safe_val = SAFE_VAL, \
103 /* Define a feature with unsigned values */
104 #define ARM64_FTR_BITS(VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL) \
105 __ARM64_FTR_BITS(FTR_UNSIGNED, VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL)
107 /* Define a feature with a signed value */
108 #define S_ARM64_FTR_BITS(VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL) \
109 __ARM64_FTR_BITS(FTR_SIGNED, VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL)
111 #define ARM64_FTR_END \
116 /* meta feature for alternatives */
117 static bool __maybe_unused
118 cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused);
122 * NOTE: Any changes to the visibility of features should be kept in
123 * sync with the documentation of the CPU feature register ABI.
125 static const struct arm64_ftr_bits ftr_id_aa64isar0[] = {
126 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_FHM_SHIFT, 4, 0),
127 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_DP_SHIFT, 4, 0),
128 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_SM4_SHIFT, 4, 0),
129 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_SM3_SHIFT, 4, 0),
130 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_SHA3_SHIFT, 4, 0),
131 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_RDM_SHIFT, 4, 0),
132 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_ATOMICS_SHIFT, 4, 0),
133 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_CRC32_SHIFT, 4, 0),
134 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_SHA2_SHIFT, 4, 0),
135 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_SHA1_SHIFT, 4, 0),
136 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_AES_SHIFT, 4, 0),
140 static const struct arm64_ftr_bits ftr_id_aa64isar1[] = {
141 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_LRCPC_SHIFT, 4, 0),
142 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_FCMA_SHIFT, 4, 0),
143 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_JSCVT_SHIFT, 4, 0),
144 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_DPB_SHIFT, 4, 0),
148 static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
149 ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_CSV3_SHIFT, 4, 0),
150 ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_CSV2_SHIFT, 4, 0),
151 ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
152 FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_SVE_SHIFT, 4, 0),
153 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_RAS_SHIFT, 4, 0),
154 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_GIC_SHIFT, 4, 0),
155 S_ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_ASIMD_SHIFT, 4, ID_AA64PFR0_ASIMD_NI),
156 S_ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_FP_SHIFT, 4, ID_AA64PFR0_FP_NI),
157 /* Linux doesn't care about the EL3 */
158 ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL3_SHIFT, 4, 0),
159 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL2_SHIFT, 4, 0),
160 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_SHIFT, 4, ID_AA64PFR0_EL1_64BIT_ONLY),
161 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL0_SHIFT, 4, ID_AA64PFR0_EL0_64BIT_ONLY),
165 static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = {
166 S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN4_SHIFT, 4, ID_AA64MMFR0_TGRAN4_NI),
167 S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN64_SHIFT, 4, ID_AA64MMFR0_TGRAN64_NI),
168 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN16_SHIFT, 4, ID_AA64MMFR0_TGRAN16_NI),
169 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_BIGENDEL0_SHIFT, 4, 0),
170 /* Linux shouldn't care about secure memory */
171 ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_SNSMEM_SHIFT, 4, 0),
172 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_BIGENDEL_SHIFT, 4, 0),
173 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_ASID_SHIFT, 4, 0),
175 * Differing PARange is fine as long as all peripherals and memory are mapped
176 * within the minimum PARange of all CPUs
178 ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_PARANGE_SHIFT, 4, 0),
182 static const struct arm64_ftr_bits ftr_id_aa64mmfr1[] = {
183 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_PAN_SHIFT, 4, 0),
184 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_LOR_SHIFT, 4, 0),
185 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_HPD_SHIFT, 4, 0),
186 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_VHE_SHIFT, 4, 0),
187 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_VMIDBITS_SHIFT, 4, 0),
188 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_HADBS_SHIFT, 4, 0),
192 static const struct arm64_ftr_bits ftr_id_aa64mmfr2[] = {
193 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_LVA_SHIFT, 4, 0),
194 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_IESB_SHIFT, 4, 0),
195 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_LSM_SHIFT, 4, 0),
196 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_UAO_SHIFT, 4, 0),
197 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_CNP_SHIFT, 4, 0),
201 static const struct arm64_ftr_bits ftr_ctr[] = {
202 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, 31, 1, 1), /* RES1 */
203 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, 29, 1, 1), /* DIC */
204 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, 28, 1, 1), /* IDC */
205 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_SAFE, 24, 4, 0), /* CWG */
206 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_SAFE, 20, 4, 0), /* ERG */
207 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, 16, 4, 1), /* DminLine */
209 * Linux can handle differing I-cache policies. Userspace JITs will
210 * make use of *minLine.
211 * If we have differing I-cache policies, report it as the weakest - VIPT.
213 ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_EXACT, 14, 2, ICACHE_POLICY_VIPT), /* L1Ip */
214 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0), /* IminLine */
218 struct arm64_ftr_reg arm64_ftr_reg_ctrel0 = {
219 .name = "SYS_CTR_EL0",
223 static const struct arm64_ftr_bits ftr_id_mmfr0[] = {
224 S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0xf), /* InnerShr */
225 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 24, 4, 0), /* FCSE */
226 ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, 20, 4, 0), /* AuxReg */
227 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 16, 4, 0), /* TCM */
228 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 12, 4, 0), /* ShareLvl */
229 S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 8, 4, 0xf), /* OuterShr */
230 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0), /* PMSA */
231 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0), /* VMSA */
235 static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
236 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, 36, 28, 0),
237 ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64DFR0_PMSVER_SHIFT, 4, 0),
238 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_CTX_CMPS_SHIFT, 4, 0),
239 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_WRPS_SHIFT, 4, 0),
240 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_BRPS_SHIFT, 4, 0),
242 * We can instantiate multiple PMU instances with different levels
245 S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64DFR0_PMUVER_SHIFT, 4, 0),
246 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64DFR0_TRACEVER_SHIFT, 4, 0),
247 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64DFR0_DEBUGVER_SHIFT, 4, 0x6),
251 static const struct arm64_ftr_bits ftr_mvfr2[] = {
252 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0), /* FPMisc */
253 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0), /* SIMDMisc */
257 static const struct arm64_ftr_bits ftr_dczid[] = {
258 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, 4, 1, 1), /* DZP */
259 ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0), /* BS */
264 static const struct arm64_ftr_bits ftr_id_isar5[] = {
265 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_RDM_SHIFT, 4, 0),
266 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_CRC32_SHIFT, 4, 0),
267 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SHA2_SHIFT, 4, 0),
268 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SHA1_SHIFT, 4, 0),
269 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_AES_SHIFT, 4, 0),
270 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SEVL_SHIFT, 4, 0),
274 static const struct arm64_ftr_bits ftr_id_mmfr4[] = {
275 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0), /* ac2 */
279 static const struct arm64_ftr_bits ftr_id_pfr0[] = {
280 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 12, 4, 0), /* State3 */
281 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 8, 4, 0), /* State2 */
282 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0), /* State1 */
283 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0), /* State0 */
287 static const struct arm64_ftr_bits ftr_id_dfr0[] = {
288 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
289 S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 24, 4, 0xf), /* PerfMon */
290 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 20, 4, 0),
291 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 16, 4, 0),
292 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 12, 4, 0),
293 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 8, 4, 0),
294 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),
295 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0),
299 static const struct arm64_ftr_bits ftr_zcr[] = {
300 ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE,
301 ZCR_ELx_LEN_SHIFT, ZCR_ELx_LEN_SIZE, 0), /* LEN */
306 * Common ftr bits for a 32bit register with all hidden, strict
307 * attributes, with 4bit feature fields and a default safe value of
308 * 0. Covers the following 32bit registers:
309 * id_isar[0-4], id_mmfr[1-3], id_pfr1, mvfr[0-1]
311 static const struct arm64_ftr_bits ftr_generic_32bits[] = {
312 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
313 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 24, 4, 0),
314 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 20, 4, 0),
315 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 16, 4, 0),
316 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 12, 4, 0),
317 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 8, 4, 0),
318 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),
319 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0),
323 /* Table for a single 32bit feature value */
324 static const struct arm64_ftr_bits ftr_single32[] = {
325 ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, 0, 32, 0),
329 static const struct arm64_ftr_bits ftr_raz[] = {
333 #define ARM64_FTR_REG(id, table) { \
335 .reg = &(struct arm64_ftr_reg){ \
337 .ftr_bits = &((table)[0]), \
340 static const struct __ftr_reg_entry {
342 struct arm64_ftr_reg *reg;
343 } arm64_ftr_regs[] = {
345 /* Op1 = 0, CRn = 0, CRm = 1 */
346 ARM64_FTR_REG(SYS_ID_PFR0_EL1, ftr_id_pfr0),
347 ARM64_FTR_REG(SYS_ID_PFR1_EL1, ftr_generic_32bits),
348 ARM64_FTR_REG(SYS_ID_DFR0_EL1, ftr_id_dfr0),
349 ARM64_FTR_REG(SYS_ID_MMFR0_EL1, ftr_id_mmfr0),
350 ARM64_FTR_REG(SYS_ID_MMFR1_EL1, ftr_generic_32bits),
351 ARM64_FTR_REG(SYS_ID_MMFR2_EL1, ftr_generic_32bits),
352 ARM64_FTR_REG(SYS_ID_MMFR3_EL1, ftr_generic_32bits),
354 /* Op1 = 0, CRn = 0, CRm = 2 */
355 ARM64_FTR_REG(SYS_ID_ISAR0_EL1, ftr_generic_32bits),
356 ARM64_FTR_REG(SYS_ID_ISAR1_EL1, ftr_generic_32bits),
357 ARM64_FTR_REG(SYS_ID_ISAR2_EL1, ftr_generic_32bits),
358 ARM64_FTR_REG(SYS_ID_ISAR3_EL1, ftr_generic_32bits),
359 ARM64_FTR_REG(SYS_ID_ISAR4_EL1, ftr_generic_32bits),
360 ARM64_FTR_REG(SYS_ID_ISAR5_EL1, ftr_id_isar5),
361 ARM64_FTR_REG(SYS_ID_MMFR4_EL1, ftr_id_mmfr4),
363 /* Op1 = 0, CRn = 0, CRm = 3 */
364 ARM64_FTR_REG(SYS_MVFR0_EL1, ftr_generic_32bits),
365 ARM64_FTR_REG(SYS_MVFR1_EL1, ftr_generic_32bits),
366 ARM64_FTR_REG(SYS_MVFR2_EL1, ftr_mvfr2),
368 /* Op1 = 0, CRn = 0, CRm = 4 */
369 ARM64_FTR_REG(SYS_ID_AA64PFR0_EL1, ftr_id_aa64pfr0),
370 ARM64_FTR_REG(SYS_ID_AA64PFR1_EL1, ftr_raz),
371 ARM64_FTR_REG(SYS_ID_AA64ZFR0_EL1, ftr_raz),
373 /* Op1 = 0, CRn = 0, CRm = 5 */
374 ARM64_FTR_REG(SYS_ID_AA64DFR0_EL1, ftr_id_aa64dfr0),
375 ARM64_FTR_REG(SYS_ID_AA64DFR1_EL1, ftr_raz),
377 /* Op1 = 0, CRn = 0, CRm = 6 */
378 ARM64_FTR_REG(SYS_ID_AA64ISAR0_EL1, ftr_id_aa64isar0),
379 ARM64_FTR_REG(SYS_ID_AA64ISAR1_EL1, ftr_id_aa64isar1),
381 /* Op1 = 0, CRn = 0, CRm = 7 */
382 ARM64_FTR_REG(SYS_ID_AA64MMFR0_EL1, ftr_id_aa64mmfr0),
383 ARM64_FTR_REG(SYS_ID_AA64MMFR1_EL1, ftr_id_aa64mmfr1),
384 ARM64_FTR_REG(SYS_ID_AA64MMFR2_EL1, ftr_id_aa64mmfr2),
386 /* Op1 = 0, CRn = 1, CRm = 2 */
387 ARM64_FTR_REG(SYS_ZCR_EL1, ftr_zcr),
389 /* Op1 = 3, CRn = 0, CRm = 0 */
390 { SYS_CTR_EL0, &arm64_ftr_reg_ctrel0 },
391 ARM64_FTR_REG(SYS_DCZID_EL0, ftr_dczid),
393 /* Op1 = 3, CRn = 14, CRm = 0 */
394 ARM64_FTR_REG(SYS_CNTFRQ_EL0, ftr_single32),
397 static int search_cmp_ftr_reg(const void *id, const void *regp)
399 return (int)(unsigned long)id - (int)((const struct __ftr_reg_entry *)regp)->sys_id;
403 * get_arm64_ftr_reg - Lookup a feature register entry using its
404 * sys_reg() encoding. With the array arm64_ftr_regs sorted in the
405 * ascending order of sys_id , we use binary search to find a matching
408 * returns - Upon success, matching ftr_reg entry for id.
409 * - NULL on failure. It is upto the caller to decide
410 * the impact of a failure.
412 static struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id)
414 const struct __ftr_reg_entry *ret;
416 ret = bsearch((const void *)(unsigned long)sys_id,
418 ARRAY_SIZE(arm64_ftr_regs),
419 sizeof(arm64_ftr_regs[0]),
426 static u64 arm64_ftr_set_value(const struct arm64_ftr_bits *ftrp, s64 reg,
429 u64 mask = arm64_ftr_mask(ftrp);
432 reg |= (ftr_val << ftrp->shift) & mask;
436 static s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new,
441 switch (ftrp->type) {
443 ret = ftrp->safe_val;
446 ret = new < cur ? new : cur;
448 case FTR_HIGHER_SAFE:
449 ret = new > cur ? new : cur;
458 static void __init sort_ftr_regs(void)
462 /* Check that the array is sorted so that we can do the binary search */
463 for (i = 1; i < ARRAY_SIZE(arm64_ftr_regs); i++)
464 BUG_ON(arm64_ftr_regs[i].sys_id < arm64_ftr_regs[i - 1].sys_id);
468 * Initialise the CPU feature register from Boot CPU values.
469 * Also initiliases the strict_mask for the register.
470 * Any bits that are not covered by an arm64_ftr_bits entry are considered
471 * RES0 for the system-wide value, and must strictly match.
473 static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new)
476 u64 strict_mask = ~0x0ULL;
480 const struct arm64_ftr_bits *ftrp;
481 struct arm64_ftr_reg *reg = get_arm64_ftr_reg(sys_reg);
485 for (ftrp = reg->ftr_bits; ftrp->width; ftrp++) {
486 u64 ftr_mask = arm64_ftr_mask(ftrp);
487 s64 ftr_new = arm64_ftr_value(ftrp, new);
489 val = arm64_ftr_set_value(ftrp, val, ftr_new);
491 valid_mask |= ftr_mask;
493 strict_mask &= ~ftr_mask;
495 user_mask |= ftr_mask;
497 reg->user_val = arm64_ftr_set_value(ftrp,
505 reg->strict_mask = strict_mask;
506 reg->user_mask = user_mask;
509 void __init init_cpu_features(struct cpuinfo_arm64 *info)
511 /* Before we start using the tables, make sure it is sorted */
514 init_cpu_ftr_reg(SYS_CTR_EL0, info->reg_ctr);
515 init_cpu_ftr_reg(SYS_DCZID_EL0, info->reg_dczid);
516 init_cpu_ftr_reg(SYS_CNTFRQ_EL0, info->reg_cntfrq);
517 init_cpu_ftr_reg(SYS_ID_AA64DFR0_EL1, info->reg_id_aa64dfr0);
518 init_cpu_ftr_reg(SYS_ID_AA64DFR1_EL1, info->reg_id_aa64dfr1);
519 init_cpu_ftr_reg(SYS_ID_AA64ISAR0_EL1, info->reg_id_aa64isar0);
520 init_cpu_ftr_reg(SYS_ID_AA64ISAR1_EL1, info->reg_id_aa64isar1);
521 init_cpu_ftr_reg(SYS_ID_AA64MMFR0_EL1, info->reg_id_aa64mmfr0);
522 init_cpu_ftr_reg(SYS_ID_AA64MMFR1_EL1, info->reg_id_aa64mmfr1);
523 init_cpu_ftr_reg(SYS_ID_AA64MMFR2_EL1, info->reg_id_aa64mmfr2);
524 init_cpu_ftr_reg(SYS_ID_AA64PFR0_EL1, info->reg_id_aa64pfr0);
525 init_cpu_ftr_reg(SYS_ID_AA64PFR1_EL1, info->reg_id_aa64pfr1);
526 init_cpu_ftr_reg(SYS_ID_AA64ZFR0_EL1, info->reg_id_aa64zfr0);
528 if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {
529 init_cpu_ftr_reg(SYS_ID_DFR0_EL1, info->reg_id_dfr0);
530 init_cpu_ftr_reg(SYS_ID_ISAR0_EL1, info->reg_id_isar0);
531 init_cpu_ftr_reg(SYS_ID_ISAR1_EL1, info->reg_id_isar1);
532 init_cpu_ftr_reg(SYS_ID_ISAR2_EL1, info->reg_id_isar2);
533 init_cpu_ftr_reg(SYS_ID_ISAR3_EL1, info->reg_id_isar3);
534 init_cpu_ftr_reg(SYS_ID_ISAR4_EL1, info->reg_id_isar4);
535 init_cpu_ftr_reg(SYS_ID_ISAR5_EL1, info->reg_id_isar5);
536 init_cpu_ftr_reg(SYS_ID_MMFR0_EL1, info->reg_id_mmfr0);
537 init_cpu_ftr_reg(SYS_ID_MMFR1_EL1, info->reg_id_mmfr1);
538 init_cpu_ftr_reg(SYS_ID_MMFR2_EL1, info->reg_id_mmfr2);
539 init_cpu_ftr_reg(SYS_ID_MMFR3_EL1, info->reg_id_mmfr3);
540 init_cpu_ftr_reg(SYS_ID_PFR0_EL1, info->reg_id_pfr0);
541 init_cpu_ftr_reg(SYS_ID_PFR1_EL1, info->reg_id_pfr1);
542 init_cpu_ftr_reg(SYS_MVFR0_EL1, info->reg_mvfr0);
543 init_cpu_ftr_reg(SYS_MVFR1_EL1, info->reg_mvfr1);
544 init_cpu_ftr_reg(SYS_MVFR2_EL1, info->reg_mvfr2);
547 if (id_aa64pfr0_sve(info->reg_id_aa64pfr0)) {
548 init_cpu_ftr_reg(SYS_ZCR_EL1, info->reg_zcr);
553 static void update_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 new)
555 const struct arm64_ftr_bits *ftrp;
557 for (ftrp = reg->ftr_bits; ftrp->width; ftrp++) {
558 s64 ftr_cur = arm64_ftr_value(ftrp, reg->sys_val);
559 s64 ftr_new = arm64_ftr_value(ftrp, new);
561 if (ftr_cur == ftr_new)
563 /* Find a safe value */
564 ftr_new = arm64_ftr_safe_value(ftrp, ftr_new, ftr_cur);
565 reg->sys_val = arm64_ftr_set_value(ftrp, reg->sys_val, ftr_new);
570 static int check_update_ftr_reg(u32 sys_id, int cpu, u64 val, u64 boot)
572 struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id);
575 update_cpu_ftr_reg(regp, val);
576 if ((boot & regp->strict_mask) == (val & regp->strict_mask))
578 pr_warn("SANITY CHECK: Unexpected variation in %s. Boot CPU: %#016llx, CPU%d: %#016llx\n",
579 regp->name, boot, cpu, val);
584 * Update system wide CPU feature registers with the values from a
585 * non-boot CPU. Also performs SANITY checks to make sure that there
586 * aren't any insane variations from that of the boot CPU.
588 void update_cpu_features(int cpu,
589 struct cpuinfo_arm64 *info,
590 struct cpuinfo_arm64 *boot)
595 * The kernel can handle differing I-cache policies, but otherwise
596 * caches should look identical. Userspace JITs will make use of
599 taint |= check_update_ftr_reg(SYS_CTR_EL0, cpu,
600 info->reg_ctr, boot->reg_ctr);
603 * Userspace may perform DC ZVA instructions. Mismatched block sizes
604 * could result in too much or too little memory being zeroed if a
605 * process is preempted and migrated between CPUs.
607 taint |= check_update_ftr_reg(SYS_DCZID_EL0, cpu,
608 info->reg_dczid, boot->reg_dczid);
610 /* If different, timekeeping will be broken (especially with KVM) */
611 taint |= check_update_ftr_reg(SYS_CNTFRQ_EL0, cpu,
612 info->reg_cntfrq, boot->reg_cntfrq);
615 * The kernel uses self-hosted debug features and expects CPUs to
616 * support identical debug features. We presently need CTX_CMPs, WRPs,
617 * and BRPs to be identical.
618 * ID_AA64DFR1 is currently RES0.
620 taint |= check_update_ftr_reg(SYS_ID_AA64DFR0_EL1, cpu,
621 info->reg_id_aa64dfr0, boot->reg_id_aa64dfr0);
622 taint |= check_update_ftr_reg(SYS_ID_AA64DFR1_EL1, cpu,
623 info->reg_id_aa64dfr1, boot->reg_id_aa64dfr1);
625 * Even in big.LITTLE, processors should be identical instruction-set
628 taint |= check_update_ftr_reg(SYS_ID_AA64ISAR0_EL1, cpu,
629 info->reg_id_aa64isar0, boot->reg_id_aa64isar0);
630 taint |= check_update_ftr_reg(SYS_ID_AA64ISAR1_EL1, cpu,
631 info->reg_id_aa64isar1, boot->reg_id_aa64isar1);
634 * Differing PARange support is fine as long as all peripherals and
635 * memory are mapped within the minimum PARange of all CPUs.
636 * Linux should not care about secure memory.
638 taint |= check_update_ftr_reg(SYS_ID_AA64MMFR0_EL1, cpu,
639 info->reg_id_aa64mmfr0, boot->reg_id_aa64mmfr0);
640 taint |= check_update_ftr_reg(SYS_ID_AA64MMFR1_EL1, cpu,
641 info->reg_id_aa64mmfr1, boot->reg_id_aa64mmfr1);
642 taint |= check_update_ftr_reg(SYS_ID_AA64MMFR2_EL1, cpu,
643 info->reg_id_aa64mmfr2, boot->reg_id_aa64mmfr2);
646 * EL3 is not our concern.
647 * ID_AA64PFR1 is currently RES0.
649 taint |= check_update_ftr_reg(SYS_ID_AA64PFR0_EL1, cpu,
650 info->reg_id_aa64pfr0, boot->reg_id_aa64pfr0);
651 taint |= check_update_ftr_reg(SYS_ID_AA64PFR1_EL1, cpu,
652 info->reg_id_aa64pfr1, boot->reg_id_aa64pfr1);
654 taint |= check_update_ftr_reg(SYS_ID_AA64ZFR0_EL1, cpu,
655 info->reg_id_aa64zfr0, boot->reg_id_aa64zfr0);
658 * If we have AArch32, we care about 32-bit features for compat.
659 * If the system doesn't support AArch32, don't update them.
661 if (id_aa64pfr0_32bit_el0(read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1)) &&
662 id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {
664 taint |= check_update_ftr_reg(SYS_ID_DFR0_EL1, cpu,
665 info->reg_id_dfr0, boot->reg_id_dfr0);
666 taint |= check_update_ftr_reg(SYS_ID_ISAR0_EL1, cpu,
667 info->reg_id_isar0, boot->reg_id_isar0);
668 taint |= check_update_ftr_reg(SYS_ID_ISAR1_EL1, cpu,
669 info->reg_id_isar1, boot->reg_id_isar1);
670 taint |= check_update_ftr_reg(SYS_ID_ISAR2_EL1, cpu,
671 info->reg_id_isar2, boot->reg_id_isar2);
672 taint |= check_update_ftr_reg(SYS_ID_ISAR3_EL1, cpu,
673 info->reg_id_isar3, boot->reg_id_isar3);
674 taint |= check_update_ftr_reg(SYS_ID_ISAR4_EL1, cpu,
675 info->reg_id_isar4, boot->reg_id_isar4);
676 taint |= check_update_ftr_reg(SYS_ID_ISAR5_EL1, cpu,
677 info->reg_id_isar5, boot->reg_id_isar5);
680 * Regardless of the value of the AuxReg field, the AIFSR, ADFSR, and
681 * ACTLR formats could differ across CPUs and therefore would have to
682 * be trapped for virtualization anyway.
684 taint |= check_update_ftr_reg(SYS_ID_MMFR0_EL1, cpu,
685 info->reg_id_mmfr0, boot->reg_id_mmfr0);
686 taint |= check_update_ftr_reg(SYS_ID_MMFR1_EL1, cpu,
687 info->reg_id_mmfr1, boot->reg_id_mmfr1);
688 taint |= check_update_ftr_reg(SYS_ID_MMFR2_EL1, cpu,
689 info->reg_id_mmfr2, boot->reg_id_mmfr2);
690 taint |= check_update_ftr_reg(SYS_ID_MMFR3_EL1, cpu,
691 info->reg_id_mmfr3, boot->reg_id_mmfr3);
692 taint |= check_update_ftr_reg(SYS_ID_PFR0_EL1, cpu,
693 info->reg_id_pfr0, boot->reg_id_pfr0);
694 taint |= check_update_ftr_reg(SYS_ID_PFR1_EL1, cpu,
695 info->reg_id_pfr1, boot->reg_id_pfr1);
696 taint |= check_update_ftr_reg(SYS_MVFR0_EL1, cpu,
697 info->reg_mvfr0, boot->reg_mvfr0);
698 taint |= check_update_ftr_reg(SYS_MVFR1_EL1, cpu,
699 info->reg_mvfr1, boot->reg_mvfr1);
700 taint |= check_update_ftr_reg(SYS_MVFR2_EL1, cpu,
701 info->reg_mvfr2, boot->reg_mvfr2);
704 if (id_aa64pfr0_sve(info->reg_id_aa64pfr0)) {
705 taint |= check_update_ftr_reg(SYS_ZCR_EL1, cpu,
706 info->reg_zcr, boot->reg_zcr);
708 /* Probe vector lengths, unless we already gave up on SVE */
709 if (id_aa64pfr0_sve(read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1)) &&
710 !sys_caps_initialised)
715 * Mismatched CPU features are a recipe for disaster. Don't even
716 * pretend to support them.
719 pr_warn_once("Unsupported CPU feature variation detected.\n");
720 add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
724 u64 read_sanitised_ftr_reg(u32 id)
726 struct arm64_ftr_reg *regp = get_arm64_ftr_reg(id);
728 /* We shouldn't get a request for an unsupported register */
730 return regp->sys_val;
733 #define read_sysreg_case(r) \
734 case r: return read_sysreg_s(r)
737 * __read_sysreg_by_encoding() - Used by a STARTING cpu before cpuinfo is populated.
738 * Read the system register on the current CPU
740 static u64 __read_sysreg_by_encoding(u32 sys_id)
743 read_sysreg_case(SYS_ID_PFR0_EL1);
744 read_sysreg_case(SYS_ID_PFR1_EL1);
745 read_sysreg_case(SYS_ID_DFR0_EL1);
746 read_sysreg_case(SYS_ID_MMFR0_EL1);
747 read_sysreg_case(SYS_ID_MMFR1_EL1);
748 read_sysreg_case(SYS_ID_MMFR2_EL1);
749 read_sysreg_case(SYS_ID_MMFR3_EL1);
750 read_sysreg_case(SYS_ID_ISAR0_EL1);
751 read_sysreg_case(SYS_ID_ISAR1_EL1);
752 read_sysreg_case(SYS_ID_ISAR2_EL1);
753 read_sysreg_case(SYS_ID_ISAR3_EL1);
754 read_sysreg_case(SYS_ID_ISAR4_EL1);
755 read_sysreg_case(SYS_ID_ISAR5_EL1);
756 read_sysreg_case(SYS_MVFR0_EL1);
757 read_sysreg_case(SYS_MVFR1_EL1);
758 read_sysreg_case(SYS_MVFR2_EL1);
760 read_sysreg_case(SYS_ID_AA64PFR0_EL1);
761 read_sysreg_case(SYS_ID_AA64PFR1_EL1);
762 read_sysreg_case(SYS_ID_AA64DFR0_EL1);
763 read_sysreg_case(SYS_ID_AA64DFR1_EL1);
764 read_sysreg_case(SYS_ID_AA64MMFR0_EL1);
765 read_sysreg_case(SYS_ID_AA64MMFR1_EL1);
766 read_sysreg_case(SYS_ID_AA64MMFR2_EL1);
767 read_sysreg_case(SYS_ID_AA64ISAR0_EL1);
768 read_sysreg_case(SYS_ID_AA64ISAR1_EL1);
770 read_sysreg_case(SYS_CNTFRQ_EL0);
771 read_sysreg_case(SYS_CTR_EL0);
772 read_sysreg_case(SYS_DCZID_EL0);
780 #include <linux/irqchip/arm-gic-v3.h>
783 feature_matches(u64 reg, const struct arm64_cpu_capabilities *entry)
785 int val = cpuid_feature_extract_field(reg, entry->field_pos, entry->sign);
787 return val >= entry->min_field_value;
791 has_cpuid_feature(const struct arm64_cpu_capabilities *entry, int scope)
795 WARN_ON(scope == SCOPE_LOCAL_CPU && preemptible());
796 if (scope == SCOPE_SYSTEM)
797 val = read_sanitised_ftr_reg(entry->sys_reg);
799 val = __read_sysreg_by_encoding(entry->sys_reg);
801 return feature_matches(val, entry);
804 static bool has_useable_gicv3_cpuif(const struct arm64_cpu_capabilities *entry, int scope)
808 if (!has_cpuid_feature(entry, scope))
811 has_sre = gic_enable_sre();
813 pr_warn_once("%s present but disabled by higher exception level\n",
819 static bool has_no_hw_prefetch(const struct arm64_cpu_capabilities *entry, int __unused)
821 u32 midr = read_cpuid_id();
823 /* Cavium ThunderX pass 1.x and 2.x */
824 return MIDR_IS_CPU_MODEL_RANGE(midr, MIDR_THUNDERX,
825 MIDR_CPU_VAR_REV(0, 0),
826 MIDR_CPU_VAR_REV(1, MIDR_REVISION_MASK));
829 static bool runs_at_el2(const struct arm64_cpu_capabilities *entry, int __unused)
831 return is_kernel_in_hyp_mode();
834 static bool hyp_offset_low(const struct arm64_cpu_capabilities *entry,
837 phys_addr_t idmap_addr = __pa_symbol(__hyp_idmap_text_start);
840 * Activate the lower HYP offset only if:
841 * - the idmap doesn't clash with it,
842 * - the kernel is not running at EL2.
844 return idmap_addr > GENMASK(VA_BITS - 2, 0) && !is_kernel_in_hyp_mode();
847 static bool has_no_fpsimd(const struct arm64_cpu_capabilities *entry, int __unused)
849 u64 pfr0 = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);
851 return cpuid_feature_extract_signed_field(pfr0,
852 ID_AA64PFR0_FP_SHIFT) < 0;
855 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
856 static int __kpti_forced; /* 0: not forced, >0: forced on, <0: forced off */
858 static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
861 char const *str = "command line option";
862 u64 pfr0 = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);
865 * For reasons that aren't entirely clear, enabling KPTI on Cavium
866 * ThunderX leads to apparent I-cache corruption of kernel text, which
867 * ends as well as you might imagine. Don't even try.
869 if (cpus_have_const_cap(ARM64_WORKAROUND_CAVIUM_27456)) {
870 str = "ARM64_WORKAROUND_CAVIUM_27456";
876 pr_info_once("kernel page table isolation forced %s by %s\n",
877 __kpti_forced > 0 ? "ON" : "OFF", str);
878 return __kpti_forced > 0;
881 /* Useful for KASLR robustness */
882 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE))
885 /* Don't force KPTI for CPUs that are not vulnerable */
886 switch (read_cpuid_id() & MIDR_CPU_MODEL_MASK) {
887 case MIDR_CAVIUM_THUNDERX2:
888 case MIDR_BRCM_VULCAN:
892 /* Defer to CPU feature registers */
893 return !cpuid_feature_extract_unsigned_field(pfr0,
894 ID_AA64PFR0_CSV3_SHIFT);
897 static int kpti_install_ng_mappings(void *__unused)
899 typedef void (kpti_remap_fn)(int, int, phys_addr_t);
900 extern kpti_remap_fn idmap_kpti_install_ng_mappings;
901 kpti_remap_fn *remap_fn;
903 static bool kpti_applied = false;
904 int cpu = smp_processor_id();
909 remap_fn = (void *)__pa_symbol(idmap_kpti_install_ng_mappings);
912 remap_fn(cpu, num_online_cpus(), __pa_symbol(swapper_pg_dir));
913 cpu_uninstall_idmap();
921 static int __init parse_kpti(char *str)
924 int ret = strtobool(str, &enabled);
929 __kpti_forced = enabled ? 1 : -1;
932 __setup("kpti=", parse_kpti);
933 #endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */
935 static int cpu_copy_el2regs(void *__unused)
938 * Copy register values that aren't redirected by hardware.
940 * Before code patching, we only set tpidr_el1, all CPUs need to copy
941 * this value to tpidr_el2 before we patch the code. Once we've done
942 * that, freshly-onlined CPUs will set tpidr_el2, so we don't need to
945 if (!alternatives_applied)
946 write_sysreg(read_sysreg(tpidr_el1), tpidr_el2);
951 static const struct arm64_cpu_capabilities arm64_features[] = {
953 .desc = "GIC system register CPU interface",
954 .capability = ARM64_HAS_SYSREG_GIC_CPUIF,
955 .def_scope = SCOPE_SYSTEM,
956 .matches = has_useable_gicv3_cpuif,
957 .sys_reg = SYS_ID_AA64PFR0_EL1,
958 .field_pos = ID_AA64PFR0_GIC_SHIFT,
959 .sign = FTR_UNSIGNED,
960 .min_field_value = 1,
962 #ifdef CONFIG_ARM64_PAN
964 .desc = "Privileged Access Never",
965 .capability = ARM64_HAS_PAN,
966 .def_scope = SCOPE_SYSTEM,
967 .matches = has_cpuid_feature,
968 .sys_reg = SYS_ID_AA64MMFR1_EL1,
969 .field_pos = ID_AA64MMFR1_PAN_SHIFT,
970 .sign = FTR_UNSIGNED,
971 .min_field_value = 1,
972 .enable = cpu_enable_pan,
974 #endif /* CONFIG_ARM64_PAN */
975 #if defined(CONFIG_AS_LSE) && defined(CONFIG_ARM64_LSE_ATOMICS)
977 .desc = "LSE atomic instructions",
978 .capability = ARM64_HAS_LSE_ATOMICS,
979 .def_scope = SCOPE_SYSTEM,
980 .matches = has_cpuid_feature,
981 .sys_reg = SYS_ID_AA64ISAR0_EL1,
982 .field_pos = ID_AA64ISAR0_ATOMICS_SHIFT,
983 .sign = FTR_UNSIGNED,
984 .min_field_value = 2,
986 #endif /* CONFIG_AS_LSE && CONFIG_ARM64_LSE_ATOMICS */
988 .desc = "Software prefetching using PRFM",
989 .capability = ARM64_HAS_NO_HW_PREFETCH,
990 .def_scope = SCOPE_SYSTEM,
991 .matches = has_no_hw_prefetch,
993 #ifdef CONFIG_ARM64_UAO
995 .desc = "User Access Override",
996 .capability = ARM64_HAS_UAO,
997 .def_scope = SCOPE_SYSTEM,
998 .matches = has_cpuid_feature,
999 .sys_reg = SYS_ID_AA64MMFR2_EL1,
1000 .field_pos = ID_AA64MMFR2_UAO_SHIFT,
1001 .min_field_value = 1,
1003 * We rely on stop_machine() calling uao_thread_switch() to set
1004 * UAO immediately after patching.
1007 #endif /* CONFIG_ARM64_UAO */
1008 #ifdef CONFIG_ARM64_PAN
1010 .capability = ARM64_ALT_PAN_NOT_UAO,
1011 .def_scope = SCOPE_SYSTEM,
1012 .matches = cpufeature_pan_not_uao,
1014 #endif /* CONFIG_ARM64_PAN */
1016 .desc = "Virtualization Host Extensions",
1017 .capability = ARM64_HAS_VIRT_HOST_EXTN,
1018 .def_scope = SCOPE_SYSTEM,
1019 .matches = runs_at_el2,
1020 .enable = cpu_copy_el2regs,
1023 .desc = "32-bit EL0 Support",
1024 .capability = ARM64_HAS_32BIT_EL0,
1025 .def_scope = SCOPE_SYSTEM,
1026 .matches = has_cpuid_feature,
1027 .sys_reg = SYS_ID_AA64PFR0_EL1,
1028 .sign = FTR_UNSIGNED,
1029 .field_pos = ID_AA64PFR0_EL0_SHIFT,
1030 .min_field_value = ID_AA64PFR0_EL0_32BIT_64BIT,
1033 .desc = "Reduced HYP mapping offset",
1034 .capability = ARM64_HYP_OFFSET_LOW,
1035 .def_scope = SCOPE_SYSTEM,
1036 .matches = hyp_offset_low,
1038 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
1040 .desc = "Kernel page table isolation (KPTI)",
1041 .capability = ARM64_UNMAP_KERNEL_AT_EL0,
1042 .def_scope = SCOPE_SYSTEM,
1043 .matches = unmap_kernel_at_el0,
1044 .enable = kpti_install_ng_mappings,
1048 /* FP/SIMD is not implemented */
1049 .capability = ARM64_HAS_NO_FPSIMD,
1050 .def_scope = SCOPE_SYSTEM,
1051 .min_field_value = 0,
1052 .matches = has_no_fpsimd,
1054 #ifdef CONFIG_ARM64_PMEM
1056 .desc = "Data cache clean to Point of Persistence",
1057 .capability = ARM64_HAS_DCPOP,
1058 .def_scope = SCOPE_SYSTEM,
1059 .matches = has_cpuid_feature,
1060 .sys_reg = SYS_ID_AA64ISAR1_EL1,
1061 .field_pos = ID_AA64ISAR1_DPB_SHIFT,
1062 .min_field_value = 1,
1065 #ifdef CONFIG_ARM64_SVE
1067 .desc = "Scalable Vector Extension",
1068 .capability = ARM64_SVE,
1069 .def_scope = SCOPE_SYSTEM,
1070 .sys_reg = SYS_ID_AA64PFR0_EL1,
1071 .sign = FTR_UNSIGNED,
1072 .field_pos = ID_AA64PFR0_SVE_SHIFT,
1073 .min_field_value = ID_AA64PFR0_SVE,
1074 .matches = has_cpuid_feature,
1075 .enable = sve_kernel_enable,
1077 #endif /* CONFIG_ARM64_SVE */
1078 #ifdef CONFIG_ARM64_RAS_EXTN
1080 .desc = "RAS Extension Support",
1081 .capability = ARM64_HAS_RAS_EXTN,
1082 .def_scope = SCOPE_SYSTEM,
1083 .matches = has_cpuid_feature,
1084 .sys_reg = SYS_ID_AA64PFR0_EL1,
1085 .sign = FTR_UNSIGNED,
1086 .field_pos = ID_AA64PFR0_RAS_SHIFT,
1087 .min_field_value = ID_AA64PFR0_RAS_V1,
1088 .enable = cpu_clear_disr,
1090 #endif /* CONFIG_ARM64_RAS_EXTN */
1094 #define HWCAP_CAP(reg, field, s, min_value, type, cap) \
1097 .def_scope = SCOPE_SYSTEM, \
1098 .matches = has_cpuid_feature, \
1100 .field_pos = field, \
1102 .min_field_value = min_value, \
1103 .hwcap_type = type, \
1107 static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
1108 HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_AES_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, HWCAP_PMULL),
1109 HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_AES_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_AES),
1110 HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA1_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_SHA1),
1111 HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA2_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_SHA2),
1112 HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA2_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, HWCAP_SHA512),
1113 HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_CRC32_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_CRC32),
1114 HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_ATOMICS_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, HWCAP_ATOMICS),
1115 HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_RDM_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_ASIMDRDM),
1116 HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA3_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_SHA3),
1117 HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SM3_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_SM3),
1118 HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SM4_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_SM4),
1119 HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_DP_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_ASIMDDP),
1120 HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_FHM_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_ASIMDFHM),
1121 HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_FP_SHIFT, FTR_SIGNED, 0, CAP_HWCAP, HWCAP_FP),
1122 HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_FP_SHIFT, FTR_SIGNED, 1, CAP_HWCAP, HWCAP_FPHP),
1123 HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_ASIMD_SHIFT, FTR_SIGNED, 0, CAP_HWCAP, HWCAP_ASIMD),
1124 HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_ASIMD_SHIFT, FTR_SIGNED, 1, CAP_HWCAP, HWCAP_ASIMDHP),
1125 HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_DPB_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_DCPOP),
1126 HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_JSCVT_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_JSCVT),
1127 HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_FCMA_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_FCMA),
1128 HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_LRCPC_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_LRCPC),
1129 #ifdef CONFIG_ARM64_SVE
1130 HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_SVE_SHIFT, FTR_UNSIGNED, ID_AA64PFR0_SVE, CAP_HWCAP, HWCAP_SVE),
1135 static const struct arm64_cpu_capabilities compat_elf_hwcaps[] = {
1136 #ifdef CONFIG_COMPAT
1137 HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_AES_SHIFT, FTR_UNSIGNED, 2, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_PMULL),
1138 HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_AES_SHIFT, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_AES),
1139 HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_SHA1_SHIFT, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_SHA1),
1140 HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_SHA2_SHIFT, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_SHA2),
1141 HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_CRC32_SHIFT, FTR_UNSIGNED, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_CRC32),
1146 static void __init cap_set_elf_hwcap(const struct arm64_cpu_capabilities *cap)
1148 switch (cap->hwcap_type) {
1150 elf_hwcap |= cap->hwcap;
1152 #ifdef CONFIG_COMPAT
1153 case CAP_COMPAT_HWCAP:
1154 compat_elf_hwcap |= (u32)cap->hwcap;
1156 case CAP_COMPAT_HWCAP2:
1157 compat_elf_hwcap2 |= (u32)cap->hwcap;
1166 /* Check if we have a particular HWCAP enabled */
1167 static bool cpus_have_elf_hwcap(const struct arm64_cpu_capabilities *cap)
1171 switch (cap->hwcap_type) {
1173 rc = (elf_hwcap & cap->hwcap) != 0;
1175 #ifdef CONFIG_COMPAT
1176 case CAP_COMPAT_HWCAP:
1177 rc = (compat_elf_hwcap & (u32)cap->hwcap) != 0;
1179 case CAP_COMPAT_HWCAP2:
1180 rc = (compat_elf_hwcap2 & (u32)cap->hwcap) != 0;
1191 static void __init setup_elf_hwcaps(const struct arm64_cpu_capabilities *hwcaps)
1193 /* We support emulation of accesses to CPU ID feature registers */
1194 elf_hwcap |= HWCAP_CPUID;
1195 for (; hwcaps->matches; hwcaps++)
1196 if (hwcaps->matches(hwcaps, hwcaps->def_scope))
1197 cap_set_elf_hwcap(hwcaps);
1201 * Check if the current CPU has a given feature capability.
1202 * Should be called from non-preemptible context.
1204 static bool __this_cpu_has_cap(const struct arm64_cpu_capabilities *cap_array,
1207 const struct arm64_cpu_capabilities *caps;
1209 if (WARN_ON(preemptible()))
1212 for (caps = cap_array; caps->matches; caps++)
1213 if (caps->capability == cap &&
1214 caps->matches(caps, SCOPE_LOCAL_CPU))
1219 void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
1222 for (; caps->matches; caps++) {
1223 if (!caps->matches(caps, caps->def_scope))
1226 if (!cpus_have_cap(caps->capability) && caps->desc)
1227 pr_info("%s %s\n", info, caps->desc);
1228 cpus_set_cap(caps->capability);
1233 * Run through the enabled capabilities and enable() it on all active
1236 void __init enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps)
1238 for (; caps->matches; caps++) {
1239 unsigned int num = caps->capability;
1241 if (!cpus_have_cap(num))
1244 /* Ensure cpus_have_const_cap(num) works */
1245 static_branch_enable(&cpu_hwcap_keys[num]);
1249 * Use stop_machine() as it schedules the work allowing
1250 * us to modify PSTATE, instead of on_each_cpu() which
1251 * uses an IPI, giving us a PSTATE that disappears when
1254 stop_machine(caps->enable, (void *)caps, cpu_online_mask);
1260 * Check for CPU features that are used in early boot
1261 * based on the Boot CPU value.
1263 static void check_early_cpu_features(void)
1265 verify_cpu_run_el();
1266 verify_cpu_asid_bits();
1270 verify_local_elf_hwcaps(const struct arm64_cpu_capabilities *caps)
1273 for (; caps->matches; caps++)
1274 if (cpus_have_elf_hwcap(caps) && !caps->matches(caps, SCOPE_LOCAL_CPU)) {
1275 pr_crit("CPU%d: missing HWCAP: %s\n",
1276 smp_processor_id(), caps->desc);
1282 verify_local_cpu_features(const struct arm64_cpu_capabilities *caps_list)
1284 const struct arm64_cpu_capabilities *caps = caps_list;
1285 for (; caps->matches; caps++) {
1286 if (!cpus_have_cap(caps->capability))
1289 * If the new CPU misses an advertised feature, we cannot proceed
1290 * further, park the cpu.
1292 if (!__this_cpu_has_cap(caps_list, caps->capability)) {
1293 pr_crit("CPU%d: missing feature: %s\n",
1294 smp_processor_id(), caps->desc);
1298 caps->enable((void *)caps);
1302 static void verify_sve_features(void)
1304 u64 safe_zcr = read_sanitised_ftr_reg(SYS_ZCR_EL1);
1305 u64 zcr = read_zcr_features();
1307 unsigned int safe_len = safe_zcr & ZCR_ELx_LEN_MASK;
1308 unsigned int len = zcr & ZCR_ELx_LEN_MASK;
1310 if (len < safe_len || sve_verify_vq_map()) {
1311 pr_crit("CPU%d: SVE: required vector length(s) missing\n",
1312 smp_processor_id());
1316 /* Add checks on other ZCR bits here if necessary */
1320 * Run through the enabled system capabilities and enable() it on this CPU.
1321 * The capabilities were decided based on the available CPUs at the boot time.
1322 * Any new CPU should match the system wide status of the capability. If the
1323 * new CPU doesn't have a capability which the system now has enabled, we
1324 * cannot do anything to fix it up and could cause unexpected failures. So
1327 static void verify_local_cpu_capabilities(void)
1329 verify_local_cpu_errata_workarounds();
1330 verify_local_cpu_features(arm64_features);
1331 verify_local_elf_hwcaps(arm64_elf_hwcaps);
1333 if (system_supports_32bit_el0())
1334 verify_local_elf_hwcaps(compat_elf_hwcaps);
1336 if (system_supports_sve())
1337 verify_sve_features();
1339 if (system_uses_ttbr0_pan())
1340 pr_info("Emulating Privileged Access Never (PAN) using TTBR0_EL1 switching\n");
1343 void check_local_cpu_capabilities(void)
1346 * All secondary CPUs should conform to the early CPU features
1347 * in use by the kernel based on boot CPU.
1349 check_early_cpu_features();
1352 * If we haven't finalised the system capabilities, this CPU gets
1353 * a chance to update the errata work arounds.
1354 * Otherwise, this CPU should verify that it has all the system
1355 * advertised capabilities.
1357 if (!sys_caps_initialised)
1358 update_cpu_errata_workarounds();
1360 verify_local_cpu_capabilities();
1363 static void __init setup_feature_capabilities(void)
1365 update_cpu_capabilities(arm64_features, "detected feature:");
1366 enable_cpu_capabilities(arm64_features);
1369 DEFINE_STATIC_KEY_FALSE(arm64_const_caps_ready);
1370 EXPORT_SYMBOL(arm64_const_caps_ready);
1372 static void __init mark_const_caps_ready(void)
1374 static_branch_enable(&arm64_const_caps_ready);
1377 extern const struct arm64_cpu_capabilities arm64_errata[];
1379 bool this_cpu_has_cap(unsigned int cap)
1381 return (__this_cpu_has_cap(arm64_features, cap) ||
1382 __this_cpu_has_cap(arm64_errata, cap));
1385 void __init setup_cpu_features(void)
1390 /* Set the CPU feature capabilies */
1391 setup_feature_capabilities();
1392 enable_errata_workarounds();
1393 mark_const_caps_ready();
1394 setup_elf_hwcaps(arm64_elf_hwcaps);
1396 if (system_supports_32bit_el0())
1397 setup_elf_hwcaps(compat_elf_hwcaps);
1401 /* Advertise that we have computed the system capabilities */
1402 set_sys_caps_initialised();
1405 * Check for sane CTR_EL0.CWG value.
1407 cwg = cache_type_cwg();
1408 cls = cache_line_size();
1410 pr_warn("No Cache Writeback Granule information, assuming cache line size %d\n",
1412 if (L1_CACHE_BYTES < cls)
1413 pr_warn("L1_CACHE_BYTES smaller than the Cache Writeback Granule (%d < %d)\n",
1414 L1_CACHE_BYTES, cls);
1417 static bool __maybe_unused
1418 cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused)
1420 return (cpus_have_const_cap(ARM64_HAS_PAN) && !cpus_have_const_cap(ARM64_HAS_UAO));
1424 * We emulate only the following system register space.
1425 * Op0 = 0x3, CRn = 0x0, Op1 = 0x0, CRm = [0, 4 - 7]
1426 * See Table C5-6 System instruction encodings for System register accesses,
1427 * ARMv8 ARM(ARM DDI 0487A.f) for more details.
1429 static inline bool __attribute_const__ is_emulated(u32 id)
1431 return (sys_reg_Op0(id) == 0x3 &&
1432 sys_reg_CRn(id) == 0x0 &&
1433 sys_reg_Op1(id) == 0x0 &&
1434 (sys_reg_CRm(id) == 0 ||
1435 ((sys_reg_CRm(id) >= 4) && (sys_reg_CRm(id) <= 7))));
1439 * With CRm == 0, reg should be one of :
1440 * MIDR_EL1, MPIDR_EL1 or REVIDR_EL1.
1442 static inline int emulate_id_reg(u32 id, u64 *valp)
1446 *valp = read_cpuid_id();
1449 *valp = SYS_MPIDR_SAFE_VAL;
1451 case SYS_REVIDR_EL1:
1452 /* IMPLEMENTATION DEFINED values are emulated with 0 */
1462 static int emulate_sys_reg(u32 id, u64 *valp)
1464 struct arm64_ftr_reg *regp;
1466 if (!is_emulated(id))
1469 if (sys_reg_CRm(id) == 0)
1470 return emulate_id_reg(id, valp);
1472 regp = get_arm64_ftr_reg(id);
1474 *valp = arm64_ftr_reg_user_value(regp);
1477 * The untracked registers are either IMPLEMENTATION DEFINED
1478 * (e.g, ID_AFR0_EL1) or reserved RAZ.
1484 static int emulate_mrs(struct pt_regs *regs, u32 insn)
1491 * sys_reg values are defined as used in mrs/msr instruction.
1492 * shift the imm value to get the encoding.
1494 sys_reg = (u32)aarch64_insn_decode_immediate(AARCH64_INSN_IMM_16, insn) << 5;
1495 rc = emulate_sys_reg(sys_reg, &val);
1497 dst = aarch64_insn_decode_register(AARCH64_INSN_REGTYPE_RT, insn);
1498 pt_regs_write_reg(regs, dst, val);
1499 arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
1505 static struct undef_hook mrs_hook = {
1506 .instr_mask = 0xfff00000,
1507 .instr_val = 0xd5300000,
1508 .pstate_mask = COMPAT_PSR_MODE_MASK,
1509 .pstate_val = PSR_MODE_EL0t,
1513 static int __init enable_mrs_emulation(void)
1515 register_undef_hook(&mrs_hook);
1519 core_initcall(enable_mrs_emulation);
1521 int cpu_clear_disr(void *__unused)
1523 /* Firmware may have left a deferred SError in this register. */
1524 write_sysreg_s(0, SYS_DISR_EL1);