feat(the): add support for FEAT_THE

Arm v8.9 introduces FEAT_THE, adding Translation Hardening Extension
Read-Check-Write mask registers, RCWMASK_EL1 and RCWSMASK_EL1.
Support this, context switching the registers and disabling
traps so lower ELs can access the new registers.

Change the FVP platform to default to handling this as a dynamic option
so the right decision can be made by the code at runtime.

Change-Id: I8775787f523639b39faf61d046ef482f73b2a562
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
diff --git a/include/arch/aarch64/arch_features.h b/include/arch/aarch64/arch_features.h
index f03c9d5..fcd0ee6 100644
--- a/include/arch/aarch64/arch_features.h
+++ b/include/arch/aarch64/arch_features.h
@@ -134,6 +134,8 @@
  * +----------------------------+
  * |	FEAT_FGT2		|
  * +----------------------------+
+ * |	FEAT_THE		|
+ * +----------------------------+
  */
 
 __attribute__((always_inline))
@@ -262,6 +264,10 @@
 CREATE_FEATURE_FUNCS(feat_s1pie, id_aa64mmfr3_el1, ID_AA64MMFR3_EL1_S1PIE_SHIFT,
 		     ID_AA64MMFR3_EL1_S1PIE_MASK, 1U, ENABLE_FEAT_S1PIE)
 
+/* FEAT_THE: Translation Hardening Extension */
+CREATE_FEATURE_FUNCS(feat_the, id_aa64pfr1_el1, ID_AA64PFR1_EL1_THE_SHIFT,
+		     ID_AA64PFR1_EL1_THE_MASK, THE_IMPLEMENTED, ENABLE_FEAT_THE)
+
 __attribute__((always_inline))
 static inline bool is_feat_sxpie_supported(void)
 {