spd: trusty: memmap trusty's code memory before peeking

This patch dynamically maps the first page of trusty's code memory,
before accessing it to find out if we are running a 32-bit or 64-bit
image.

On Tegra platforms, this means we have to increase the mappings to
accomodate the new memmap entry.

Change-Id: If370d1e6cfcccd69b260134c1b462d8d17bee03d
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>

plat/nvidia/tegra/soc/t186/platform_t186.mk

 #
-# Copyright (c) 2015-2017, ARM Limited and Contributors. All rights reserved.
+# Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -33,7 +33,7 @@ $(eval $(call add_define,PLATFORM_MAX_CPUS_PER_CLUSTER))
 MAX_XLAT_TABLES				:= 24
 $(eval $(call add_define,MAX_XLAT_TABLES))
 
-MAX_MMAP_REGIONS			:= 24
+MAX_MMAP_REGIONS			:= 25
 $(eval $(call add_define,MAX_MMAP_REGIONS))
 
 # platform files

plat/nvidia/tegra/soc/t210/platform_t210.mk

 #
-# Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
+# Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -19,7 +19,7 @@ $(eval $(call add_define,PLATFORM_MAX_CPUS_PER_CLUSTER))
 MAX_XLAT_TABLES				:= 10
 $(eval $(call add_define,MAX_XLAT_TABLES))
 
-MAX_MMAP_REGIONS			:= 15
+MAX_MMAP_REGIONS			:= 16
 $(eval $(call add_define,MAX_MMAP_REGIONS))
 
 ENABLE_WDT_LEGACY_FIQ_HANDLING		:= 1

services/spd/trusty/trusty.c

@@ -7,6 +7,7 @@
 #include <assert.h>
 #include <stdbool.h>
 #include <string.h>
+#include <xlat_tables_v2.h>
 
 #include <arch_helpers.h>
 #include <bl31/bl31.h>
@@ -412,6 +413,14 @@ static int32_t trusty_setup(void)
 		return -1;
 	}
 
+	/* memmap first page of trusty's code memory before peeking */
+	ret = mmap_add_dynamic_region(ep_info->pc, /* PA */
+			ep_info->pc, /* VA */
+			PAGE_SIZE, /* size */
+			MT_SECURE | MT_RW_DATA); /* attrs */
+	assert(ret == 0);
+
+	/* peek into trusty's code to see if we have a 32-bit or 64-bit image */
 	instr = *(uint32_t *)ep_info->pc;
 
 	if (instr >> 24 == 0xeaU) {
@@ -424,6 +433,9 @@ static int32_t trusty_setup(void)
 		return -1;
 	}
 
+	/* unmap trusty's memory page */
+	(void)mmap_remove_dynamic_region(ep_info->pc, PAGE_SIZE);
+
 	SET_PARAM_HEAD(ep_info, PARAM_EP, VERSION_1, SECURE | EP_ST_ENABLE);
 	if (!aarch32)
 		ep_info->spsr = SPSR_64(MODE_EL1, MODE_SP_ELX,