Setup VBAR_EL3 incrementally

This patch ensures that VBAR_EL3 points to the simple stack-less
'early_exceptions' when the C runtime stack is not correctly setup to
use the more complex 'runtime_exceptions'. It is initialised to
'runtime_exceptions' once this is done.

This patch also moves all exception vectors into a '.vectors' section
and modifies linker scripts to place all such sections together. This
will minimize space wastage from alignment restrictions.

Change-Id: I8c3e596ea3412c8bd582af9e8d622bb1cb2e049d
diff --git a/common/psci/psci_entry.S b/common/psci/psci_entry.S
index a6a1a6f..28a4143 100644
--- a/common/psci/psci_entry.S
+++ b/common/psci/psci_entry.S
@@ -63,6 +63,17 @@
 
 psci_aff_common_finish_entry:
 	adr	x22, psci_afflvl_power_on_finish
+
+	/* ---------------------------------------------
+	 * Exceptions should not occur at this point.
+	 * Set VBAR in order to handle and report any
+	 * that do occur
+	 * ---------------------------------------------
+	 */
+	adr	x0, early_exceptions
+	msr	vbar_el3, x0
+	isb
+
 	bl	read_mpidr
 	mov	x19, x0
 	bl	platform_set_coherent_stack
@@ -90,6 +101,16 @@
 	mov	x0, x19
 	bl	platform_set_stack
 
+	/* ---------------------------------------------
+	 * Now that the execution stack has been set
+	 * up, enable full runtime exception handling.
+	 * Since we're just about to leave this EL with
+	 * ERET, we don't need an ISB here
+	 * ---------------------------------------------
+	 */
+	adr	x0, runtime_exceptions
+	msr	vbar_el3, x0
+
 	/* --------------------------------------------
 	 * Use the size of the general purpose register
 	 * context to restore the register state