Add macro to check whether the CPU implements an EL

Replace all instances of checks with the new macro.

Change-Id: I0eec39b9376475a1a9707a3115de9d36f88f8a2a
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>

bl1/aarch64/bl1_context_mgmt.c

 /*
- * Copyright (c) 2015-2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2017, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -72,8 +72,7 @@ void bl1_prepare_next_image(unsigned int image_id)
 	 * Ensure that the build flag to save AArch32 system registers in CPU
 	 * context is not set for AArch64-only platforms.
 	 */
-	if (((read_id_aa64pfr0_el1() >> ID_AA64PFR0_EL1_SHIFT)
-			& ID_AA64PFR0_ELX_MASK) == 0x1) {
+	if (EL_IMPLEMENTED(1) == EL_IMPL_A64ONLY) {
 		ERROR("EL1 supports AArch64-only. Please set build flag "
 				"CTX_INCLUDE_AARCH32_REGS = 0");
 		panic();
@@ -99,9 +98,8 @@ void bl1_prepare_next_image(unsigned int image_id)
 		next_bl_ep->spsr = SPSR_64(MODE_EL1, MODE_SP_ELX,
 				   DISABLE_ALL_EXCEPTIONS);
 	} else {
-		/* Use EL2 if supported else use EL1. */
-		if (read_id_aa64pfr0_el1() &
-			(ID_AA64PFR0_ELX_MASK << ID_AA64PFR0_EL2_SHIFT)) {
+		/* Use EL2 if supported; else use EL1. */
+		if (EL_IMPLEMENTED(2)) {
 			next_bl_ep->spsr = SPSR_64(MODE_EL2, MODE_SP_ELX,
 				DISABLE_ALL_EXCEPTIONS);
 		} else {

bl31/bl31_main.c

@@ -172,8 +172,7 @@ void bl31_prepare_next_image_entry(void)
 	 * Ensure that the build flag to save AArch32 system registers in CPU
 	 * context is not set for AArch64-only platforms.
 	 */
-	if (((read_id_aa64pfr0_el1() >> ID_AA64PFR0_EL1_SHIFT)
-			& ID_AA64PFR0_ELX_MASK) == 0x1) {
+	if (EL_IMPLEMENTED(1) == EL_IMPL_A64ONLY) {
 		ERROR("EL1 supports AArch64-only. Please set build flag "
 				"CTX_INCLUDE_AARCH32_REGS = 0");
 		panic();

include/lib/aarch64/arch.h

@@ -134,6 +134,10 @@
 #define ID_AA64PFR0_EL3_SHIFT	12
 #define ID_AA64PFR0_ELX_MASK	0xf
 
+#define EL_IMPL_NONE		0
+#define EL_IMPL_A64ONLY		1
+#define EL_IMPL_A64_A32		2
+
 #define ID_AA64PFR0_GIC_SHIFT	24
 #define ID_AA64PFR0_GIC_WIDTH	4
 #define ID_AA64PFR0_GIC_MASK	((1 << ID_AA64PFR0_GIC_WIDTH) - 1)

include/lib/aarch64/arch_helpers.h

@@ -352,6 +352,14 @@ DEFINE_RENAME_SYSREG_WRITE_FUNC(icc_eoir1_el1, ICC_EOIR1_EL1)
 #define IS_IN_EL1() IS_IN_EL(1)
 #define IS_IN_EL3() IS_IN_EL(3)
 
+/*
+ * Check if an EL is implemented from AA64PFR0 register fields. 'el' argument
+ * must be one of 1, 2 or 3.
+ */
+#define EL_IMPLEMENTED(el) \
+	((read_id_aa64pfr0_el1() >> ID_AA64PFR0_EL##el##_SHIFT) \
+		& ID_AA64PFR0_ELX_MASK)
+
 /* Previously defined accesor functions with incomplete register names  */
 
 #define read_current_el()	read_CurrentEl()

lib/el3_runtime/aarch64/context_mgmt.c

@@ -229,8 +229,7 @@ void cm_prepare_el3_exit(uint32_t security_state)
 			sctlr_elx &= ~SCTLR_EE_BIT;
 			sctlr_elx |= SCTLR_EL2_RES1;
 			write_sctlr_el2(sctlr_elx);
-		} else if (read_id_aa64pfr0_el1() &
-			   (ID_AA64PFR0_ELX_MASK << ID_AA64PFR0_EL2_SHIFT)) {
+		} else if (EL_IMPLEMENTED(2)) {
 			/* EL2 present but unused, need to disable safely */
 
 			/* HCR_EL2 = 0, except RW bit set to match SCR_EL3 */

plat/arm/common/arm_common.c

@@ -137,15 +137,11 @@ uint32_t arm_get_spsr_for_bl32_entry(void)
 #ifndef AARCH32
 uint32_t arm_get_spsr_for_bl33_entry(void)
 {
-	unsigned long el_status;
 	unsigned int mode;
 	uint32_t spsr;
 
 	/* Figure out what mode we enter the non-secure world in */
-	el_status = read_id_aa64pfr0_el1() >> ID_AA64PFR0_EL2_SHIFT;
-	el_status &= ID_AA64PFR0_ELX_MASK;
-
-	mode = (el_status) ? MODE_EL2 : MODE_EL1;
+	mode = EL_IMPLEMENTED(2) ? MODE_EL2 : MODE_EL1;
 
 	/*
 	 * TODO: Consider the possibility of specifying the SPSR in

plat/mediatek/mt6795/bl31_plat_setup.c

 /*
- * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -360,20 +360,15 @@ void enable_ns_access_to_cpuectlr(void)
 static entry_point_info_t *bl31_plat_get_next_kernel64_ep_info(void)
 {
 	entry_point_info_t *next_image_info;
-	unsigned long el_status;
 	unsigned int mode;
 
-	el_status = 0;
 	mode = 0;
 
 	/* Kernel image is always non-secured */
 	next_image_info = &bl33_image_ep_info;
 
 	/* Figure out what mode we enter the non-secure world in */
-	el_status = read_id_aa64pfr0_el1() >> ID_AA64PFR0_EL2_SHIFT;
-	el_status &= ID_AA64PFR0_ELX_MASK;
-
-	if (el_status) {
+	if (EL_IMPLEMENTED(2)) {
 		INFO("Kernel_EL2\n");
 		mode = MODE_EL2;
 	} else{

plat/qemu/qemu_bl2_setup.c

@@ -226,15 +226,11 @@ static uint32_t qemu_get_spsr_for_bl32_entry(void)
  ******************************************************************************/
 static uint32_t qemu_get_spsr_for_bl33_entry(void)
 {
-	unsigned long el_status;
 	unsigned int mode;
 	uint32_t spsr;
 
 	/* Figure out what mode we enter the non-secure world in */
-	el_status = read_id_aa64pfr0_el1() >> ID_AA64PFR0_EL2_SHIFT;
-	el_status &= ID_AA64PFR0_ELX_MASK;
-
-	mode = (el_status) ? MODE_EL2 : MODE_EL1;
+	mode = EL_IMPLEMENTED(2) ? MODE_EL2 : MODE_EL1;
 
 	/*
 	 * TODO: Consider the possibility of specifying the SPSR in