Merge "el3_entrypoint_common: avoid overwriting arg3" into integration

include/arch/aarch32/el3_common_macros.S

 /*
- * Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2020, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -329,6 +329,11 @@
 		bl	inv_dcache_range
 #endif
 
+		/*
+		 * zeromem uses r12 whereas it is used to save previous BL arg3,
+		 * save it in r7
+		 */
+		mov	r7, r12
 		ldr	r0, =__BSS_START__
 		ldr	r1, =__BSS_SIZE__
 		bl	zeromem
@@ -339,6 +344,9 @@
 		bl	zeromem
 #endif
 
+		/* Restore r12 */
+		mov	r12, r7
+
 #if defined(IMAGE_BL1) || (defined(IMAGE_BL2) && BL2_AT_EL3 && BL2_IN_XIP_MEM)
 		/* -----------------------------------------------------
 		 * Copy data from ROM to RAM.