Introduce IS_IN_ELX() macros

The goal of these macros is to improve code readability by providing
a concise way to check whether we are running in the expected
exception level.

Change-Id: If9aebadfb6299a5196e9a582b442f0971d9909b1

common/bl_common.c

@@ -106,9 +106,7 @@ void __dead2 raise_el(aapcs64_params_t *args)
  */
 void __dead2 change_el(el_change_info_t *info)
 {
-	unsigned long current_el = read_current_el();
+	if (IS_IN_EL3()) {
-
-	if (GET_EL(current_el) == MODE_EL3) {
 		/*
 		 * We can go anywhere from EL3. So find where.
 		 * TODO: Lots to do if we are going non-secure.
@@ -551,7 +549,6 @@ void __dead2 run_image(unsigned long entrypoint,
 		       void *second_arg)
 {
 	el_change_info_t run_image_info;
-	unsigned long current_el = read_current_el();
 
 	/* Tell next EL what we want done */
 	run_image_info.args.arg0 = RUN_IMAGE;
@@ -565,7 +562,7 @@ void __dead2 run_image(unsigned long entrypoint,
 	 * to jump to a higher EL and issue an SMC. Contents of argY
 	 * will go into the general purpose register xY e.g. arg0->x0
 	 */
-	if (GET_EL(current_el) == MODE_EL3) {
+	if (IS_IN_EL3()) {
 		run_image_info.args.arg1 = (unsigned long) first_arg;
 		run_image_info.args.arg2 = (unsigned long) second_arg;
 	} else {

include/lib/aarch64/arch_helpers.h

@@ -264,5 +264,10 @@ extern void write_cpuectlr(unsigned long);
 extern void write_cptr_el2(unsigned long);
 extern void write_cptr_el3(unsigned long);
 
+#define IS_IN_EL(x) \
+	(GET_EL(read_current_el()) == MODE_EL##x)
+
+#define IS_IN_EL1() IS_IN_EL(1)
+#define IS_IN_EL3() IS_IN_EL(3)
 
 #endif /* __ARCH_HELPERS_H__ */

plat/fvp/aarch64/plat_common.c

@@ -52,7 +52,6 @@ static unsigned long platform_config[CONFIG_LIMIT];
 void enable_mmu()
 {
 	unsigned long mair, tcr, ttbr, sctlr;
-	unsigned long current_el = read_current_el();
 
 	/* Set the attributes in the right indices of the MAIR */
 	mair = MAIR_ATTR_SET(ATTR_DEVICE, ATTR_DEVICE_INDEX);
@@ -68,7 +67,7 @@ void enable_mmu()
 	/* Set TTBR bits as well */
 	ttbr = (unsigned long) l1_xlation_table;
 
-	if (GET_EL(current_el) == MODE_EL3) {
+	if (IS_IN_EL3()) {
 		assert((read_sctlr_el3() & SCTLR_M_BIT) == 0);
 
 		write_mair_el3(mair);