S-EL2 Support: Check for AArch64

Check that entry point information requesting S-EL2
has AArch64 as an execution state during context setup.
Signed-off-by: Artsem Artsemenka <artsem.artsemenka@arm.com>
Change-Id: I447263692fed6e55c1b076913e6eb73b1ea735b7

include/arch/aarch64/arch.h

@@ -141,7 +141,7 @@
 #define ID_AA64PFR0_SVE_SHIFT	U(32)
 #define ID_AA64PFR0_SVE_MASK	ULL(0xf)
 #define ID_AA64PFR0_SEL2_SHIFT	U(36)
-#define ID_AA64PFR0_SEL2_MASK	U(0xf)
+#define ID_AA64PFR0_SEL2_MASK	ULL(0xf)
 #define ID_AA64PFR0_MPAM_SHIFT	U(40)
 #define ID_AA64PFR0_MPAM_MASK	ULL(0xf)
 #define ID_AA64PFR0_DIT_SHIFT	U(48)

lib/el3_runtime/aarch64/context_mgmt.c

@@ -182,8 +182,14 @@ void cm_setup_context(cpu_context_t *ctx, const entry_point_info_t *ep)
 	}
 
 	/* Enable S-EL2 if the next EL is EL2 and security state is secure */
-	if ((security_state == SECURE) && (GET_EL(ep->spsr) == MODE_EL2))
+	if ((security_state == SECURE) && (GET_EL(ep->spsr) == MODE_EL2)) {
+		if (GET_RW(ep->spsr) != MODE_RW_64) {
+			ERROR("S-EL2 can not be used in AArch32.");
+			panic();
+		}
+
 		scr_el3 |= SCR_EEL2_BIT;
+	}
 
 	/*
 	 * Initialise SCTLR_EL1 to the reset value corresponding to the target