feat(tcr2): support FEAT_TCR2

Arm v8.9 introduces FEAT_TCR2, adding extended translation control
registers. Support this, context switching TCR2_EL2 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.

Signed-off-by: Mark Brown <broonie@kernel.org>
Change-Id: I297452acd8646d58bac64fc15e05b06a543e5148
diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c
index 4d2079d..507a8ce 100644
--- a/lib/el3_runtime/aarch64/context_mgmt.c
+++ b/lib/el3_runtime/aarch64/context_mgmt.c
@@ -348,6 +348,13 @@
 #endif
 
 	/*
+	 * SCR_EL3.TCR2EN: Enable access to TCR2_ELx for AArch64 if present.
+	 */
+	if (is_feat_tcr2_supported() && (GET_RW(ep->spsr) == MODE_RW_64)) {
+		scr_el3 |= SCR_TCR2EN_BIT;
+	}
+
+	/*
 	 * CPTR_EL3 was initialized out of reset, copy that value to the
 	 * context register.
 	 */
@@ -884,6 +891,9 @@
 		if (is_feat_hcx_supported()) {
 			write_ctx_reg(el2_sysregs_ctx, CTX_HCRX_EL2, read_hcrx_el2());
 		}
+		if (is_feat_tcr2_supported()) {
+			write_ctx_reg(el2_sysregs_ctx, CTX_TCR2_EL2, read_tcr2_el2());
+		}
 	}
 }
 
@@ -944,6 +954,9 @@
 		if (is_feat_hcx_supported()) {
 			write_hcrx_el2(read_ctx_reg(el2_sysregs_ctx, CTX_HCRX_EL2));
 		}
+		if (is_feat_tcr2_supported()) {
+			write_tcr2_el2(read_ctx_reg(el2_sysregs_ctx, CTX_TCR2_EL2));
+		}
 	}
 }
 #endif /* CTX_INCLUDE_EL2_REGS */