arm64: cpufeature: TWED support detection

virt inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I40FGG
CVE: NA

-----------------------------

TWE Delay is an optional feature in ARMv8.6 Extensions. This patch
detect this feature.
Signed-off-by: NZengruan Ye <yezengruan@huawei.com>
Signed-off-by: NJingyi Wang <wangjingyi11@huawei.com>
Reviewed-by: NKeqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

arch/arm64/Kconfig

@@ -1794,6 +1794,16 @@ config ARM64_MTE
 
 endmenu
 
+menu "ARMv8.6 architectural features"
+
+config ARM64_TWED
+	bool "Enable support for delayed trapping of WFE"
+	default y
+	help
+	  Delayed Trapping of WFE (part of the ARMv8.6 Extensions)
+
+endmenu
+
 config ARM64_SVE
 	bool "ARM Scalable Vector Extension support"
 	default y

arch/arm64/include/asm/cpucaps.h

@@ -69,7 +69,8 @@
 #define ARM64_HAS_MPAM				59
 #define ARM64_WORKAROUND_HISI_HIP08_RU_PREFETCH 60
 #define ARM64_CLEARPAGE_STNP			61
+#define ARM64_HAS_TWED				62
 
-#define ARM64_NCAPS				62
+#define ARM64_NCAPS				63
 
 #endif /* __ASM_CPUCAPS_H */

arch/arm64/kernel/cpufeature.c

@@ -2192,6 +2192,18 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
 		.matches = can_clearpage_use_stnp,
 	},
+#ifdef CONFIG_ARM64_TWED
+	{
+		.desc = "Delayed Trapping of WFE",
+		.capability = ARM64_HAS_TWED,
+		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
+		.matches = has_cpuid_feature,
+		.sys_reg = SYS_ID_AA64MMFR1_EL1,
+		.field_pos = ID_AA64MMFR1_TWED_SHIFT,
+		.sign = FTR_UNSIGNED,
+		.min_field_value = 1,
+	},
+#endif
 	{},
 };