refactor(cm): enable S-EL2 globally for all contexts

Currently, S-EL2 is being enabled specifically while we are in
secure context and gets toggled up when we exit secure world.
This behavior is not ideal and needs correction.

Enabling the S-EL2 via SCR_EL3.EEL2 register setting should be
global and this patch addresses it.

Change-Id: If6c39ca258f2fefa835c4b51e0f6b68165fd2e35
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>

lib/el3_runtime/aarch64/context_mgmt.c

@@ -135,16 +135,6 @@ static void setup_secure_context(cpu_context_t *ctx, const struct entry_point_in
 	}
 #endif /* CTX_INCLUDE_MTE_REGS */
 
-	/* Enable S-EL2 if the next EL is EL2 and S-EL2 is present */
-	if ((GET_EL(ep->spsr) == MODE_EL2) && is_feat_sel2_supported()) {
-		if (GET_RW(ep->spsr) != MODE_RW_64) {
-			ERROR("S-EL2 can not be used in AArch32\n.");
-			panic();
-		}
-
-		scr_el3 |= SCR_EEL2_BIT;
-	}
-
 	write_ctx_reg(state, CTX_SCR_EL3, scr_el3);
 
 	/*
@@ -485,6 +475,13 @@ static void setup_context_common(cpu_context_t *ctx, const entry_point_info_t *e
 		scr_el3 |= SCR_TWEDEn_BIT;
 	}
 
+#if IMAGE_BL31 && defined(SPD_spmd) && SPMD_SPM_AT_SEL2
+	/* Enable S-EL2 if FEAT_SEL2 is implemented for all the contexts. */
+	if (is_feat_sel2_supported()) {
+		scr_el3 |= SCR_EEL2_BIT;
+	}
+#endif /* (IMAGE_BL31 && defined(SPD_spmd) && SPMD_SPM_AT_SEL2) */
+
 	/*
 	 * Populate EL3 state so that we've the right context
 	 * before doing ERET