Add descriptor based image management support in BL1

As of now BL1 loads and execute BL2 based on hard coded information
provided in BL1. But due to addition of support for upcoming Firmware
Update feature, BL1 now require more flexible approach to load and
run different images using information provided by the platform.

This patch adds new mechanism to load and execute images based on
platform provided image id's. BL1 now queries the platform to fetch
the image id of the next image to be loaded and executed. In order
to achieve this, a new struct image_desc_t was added which holds the
information about images, such as: ep_info and image_info.

This patch introduces following platform porting functions:

unsigned int bl1_plat_get_next_image_id(void);
	This is used to identify the next image to be loaded
	and executed by BL1.

struct image_desc *bl1_plat_get_image_desc(unsigned int image_id);
	This is used to retrieve the image_desc for given image_id.

void bl1_plat_set_ep_info(unsigned int image_id,
str...

bl1/aarch64/bl1_entrypoint.S

@@ -69,10 +69,14 @@ func bl1_entrypoint
 
 	/* --------------------------------------------------
 	 * Initialize platform and jump to our c-entry point
-	 * for this type of reset. Panic if it returns
+	 * for this type of reset.
 	 * --------------------------------------------------
 	 */
 	bl	bl1_main
-panic:
-	b	panic
+
+	/* --------------------------------------------------
+	 * Do the transition to next boot image.
+	 * --------------------------------------------------
+	 */
+	b	el3_exit
 endfunc bl1_entrypoint

bl1/aarch64/bl1_exceptions.S

@@ -31,6 +31,7 @@
 #include <arch.h>
 #include <asm_macros.S>
 #include <bl_common.h>
+#include <context.h>
 
 	.globl	bl1_exceptions
 
@@ -114,10 +115,12 @@ SynchronousExceptionA64:
 	/* Enable the SError interrupt */
 	msr	daifclr, #DAIF_ABT_BIT
 
+	str	x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
+
 	/* Expect only SMC exceptions */
-	mrs	x19, esr_el3
-	ubfx	x20, x19, #ESR_EC_SHIFT, #ESR_EC_LENGTH
-	cmp	x20, #EC_AARCH64_SMC
+	mrs	x30, esr_el3
+	ubfx	x30, x30, #ESR_EC_SHIFT, #ESR_EC_LENGTH
+	cmp	x30, #EC_AARCH64_SMC
 	b.ne	unexpected_sync_exception
 
 	b	smc_handler64
@@ -178,6 +181,14 @@ SErrorA32:
 
 
 func smc_handler64
+	/* ----------------------------------------------
+	 * Switch back to SP_EL0 for the C runtime stack.
+	 * ----------------------------------------------
+	 */
+	ldr	x30, [sp, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP]
+	msr	spsel, #0
+	mov	sp, x30
+
 	/* ---------------------------------------------------------------------
 	 * Only a single SMC exception from BL2 to ask BL1 to pass EL3 control
 	 * to BL31 is expected here. It expects:

bl1/bl1.mk

 #
-# Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
+# Copyright (c) 2013-2015, 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:
@@ -32,6 +32,11 @@ BL1_SOURCES		+=	bl1/bl1_main.c				\
 				bl1/aarch64/bl1_arch_setup.c		\
 				bl1/aarch64/bl1_entrypoint.S		\
 				bl1/aarch64/bl1_exceptions.S		\
-				lib/cpus/aarch64/cpu_helpers.S
+				bl1/bl1_context_mgmt.c			\
+				common/aarch64/context.S		\
+				common/context_mgmt.c			\
+				lib/cpus/aarch64/cpu_helpers.S		\
+				plat/common/plat_bl1_common.c
+
 
 BL1_LINKERFILE		:=	bl1/bl1.ld.S

bl1/bl1_context_mgmt.c

+/*
+ * Copyright (c) 2015, 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:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <arch_helpers.h>
+#include <assert.h>
+#include <context.h>
+#include <context_mgmt.h>
+#include <debug.h>
+#include <platform.h>
+
+/*
+ * Following array will be used for context management.
+ * There are 2 instances, for the Secure and Non-Secure contexts.
+ */
+static cpu_context_t bl1_cpu_context[2];
+
+/* Following contains the cpu context pointers. */
+static void *bl1_cpu_context_ptr[2];
+
+
+void *cm_get_context(uint32_t security_state)
+{
+	assert(sec_state_is_valid(security_state));
+	return bl1_cpu_context_ptr[security_state];
+}
+
+void cm_set_context(void *context, uint32_t security_state)
+{
+	assert(sec_state_is_valid(security_state));
+	bl1_cpu_context_ptr[security_state] = context;
+}
+
+/*******************************************************************************
+ * This function prepares the context for Secure/Normal world images.
+ * Normal world images are transitioned to EL2(if supported) else EL1.
+ ******************************************************************************/
+void bl1_prepare_next_image(unsigned int image_id)
+{
+	unsigned int security_state;
+	image_desc_t *image_desc;
+	entry_point_info_t *next_bl_ep;
+
+	/* Get the image descriptor. */
+	image_desc = bl1_plat_get_image_desc(image_id);
+	assert(image_desc);
+
+	/* Get the entry point info. */
+	next_bl_ep = &image_desc->ep_info;
+
+	/* Get the image security state. */
+	security_state = GET_SEC_STATE(next_bl_ep->h.attr);
+
+	/* Setup the Secure/Non-Secure context if not done already. */
+	if (!cm_get_context(security_state))
+		cm_set_context(&bl1_cpu_context[security_state], security_state);
+
+	/* Prepare the SPSR for the next BL image. */
+	if (security_state == SECURE) {
+		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)) {
+			next_bl_ep->spsr = SPSR_64(MODE_EL2, MODE_SP_ELX,
+				DISABLE_ALL_EXCEPTIONS);
+		} else {
+			next_bl_ep->spsr = SPSR_64(MODE_EL1, MODE_SP_ELX,
+			   DISABLE_ALL_EXCEPTIONS);
+		}
+	}
+
+	/* Allow platform to make change */
+	bl1_plat_set_ep_info(image_id, next_bl_ep);
+
+	/* Prepare the context for the next BL image. */
+	cm_init_my_context(next_bl_ep);
+	cm_prepare_el3_exit(security_state);
+
+	/* Indicate that image is in execution state. */
+	image_desc->state = IMAGE_STATE_EXECUTED;
+
+	print_entry_point_info(next_bl_ep);
+}

bl1/bl1_main.c

@@ -38,34 +38,8 @@
 #include <platform_def.h>
 #include "bl1_private.h"
 
-/*******************************************************************************
- * Runs BL2 from the given entry point. It results in dropping the
- * exception level
- ******************************************************************************/
-static void __dead2 bl1_run_bl2(entry_point_info_t *bl2_ep)
-{
-	/* Check bl2 security state is expected as secure */
-	assert(GET_SECURITY_STATE(bl2_ep->h.attr) == SECURE);
-	/* Check NS Bit is also set as secure */
-	assert(!(read_scr_el3() & SCR_NS_BIT));
-
-	bl1_arch_next_el_setup();
-
-	write_spsr_el3(bl2_ep->spsr);
-	write_elr_el3(bl2_ep->pc);
 
-	NOTICE("BL1: Booting BL2\n");
-	print_entry_point_info(bl2_ep);
-
-	eret(bl2_ep->args.arg0,
-		bl2_ep->args.arg1,
-		bl2_ep->args.arg2,
-		bl2_ep->args.arg3,
-		bl2_ep->args.arg4,
-		bl2_ep->args.arg5,
-		bl2_ep->args.arg6,
-		bl2_ep->args.arg7);
-}
+static void bl1_load_bl2(void);
 
 /*******************************************************************************
  * The next function has a weak definition. Platform specific code can override
@@ -88,7 +62,8 @@ void bl1_init_bl2_mem_layout(const meminfo_t *bl1_mem_layout,
 
 	/* Check that BL1's memory is lying outside of the free memory */
 	assert((BL1_RAM_LIMIT <= bl1_mem_layout->free_base) ||
-	       (BL1_RAM_BASE >= bl1_mem_layout->free_base + bl1_mem_layout->free_size));
+	       (BL1_RAM_BASE >= bl1_mem_layout->free_base +
+				bl1_mem_layout->free_size));
 
 	/* Remove BL1 RW data from the scope of memory visible to BL2 */
 	*bl2_mem_layout = *bl1_mem_layout;
@@ -102,13 +77,13 @@ void bl1_init_bl2_mem_layout(const meminfo_t *bl1_mem_layout,
 
 /*******************************************************************************
  * Function to perform late architectural and platform specific initialization.
- * It also locates and loads the BL2 raw binary image in the trusted DRAM. Only
- * called by the primary cpu after a cold boot.
- * TODO: Add support for alternative image load mechanism e.g using virtio/elf
- * loader etc.
+ * It also queries the platform to load and run next BL image. Only called
+ * by the primary cpu after a cold boot.
  ******************************************************************************/
 void bl1_main(void)
 {
+	unsigned int image_id;
+
 	/* Announce our arrival */
 	NOTICE(FIRMWARE_WELCOME_STR);
 	NOTICE("BL1: %s\n", version_string);
@@ -116,11 +91,6 @@ void bl1_main(void)
 
 	INFO("BL1: RAM 0x%lx - 0x%lx\n", BL1_RAM_BASE, BL1_RAM_LIMIT);
 
-	image_info_t bl2_image_info = { {0} };
-	entry_point_info_t bl2_ep = { {0} };
-	meminfo_t *bl1_tzram_layout;
-	meminfo_t *bl2_tzram_layout = 0x0;
-	int err;
 
 #if DEBUG
 	unsigned long val;
@@ -150,28 +120,59 @@ void bl1_main(void)
 	/* Perform remaining generic architectural setup from EL3 */
 	bl1_arch_setup();
 
+#if TRUSTED_BOARD_BOOT
+	/* Initialize authentication module */
+	auth_mod_init();
+#endif /* TRUSTED_BOARD_BOOT */
+
 	/* Perform platform setup in BL1. */
 	bl1_platform_setup();
 
-	SET_PARAM_HEAD(&bl2_image_info, PARAM_IMAGE_BINARY, VERSION_1, 0);
-	SET_PARAM_HEAD(&bl2_ep, PARAM_EP, VERSION_1, 0);
+	/* Get the image id of next image to load and run. */
+	image_id = bl1_plat_get_next_image_id();
+
+	if (image_id == BL2_IMAGE_ID)
+		bl1_load_bl2();
+
+	bl1_prepare_next_image(image_id);
+}
+
+/*******************************************************************************
+ * This function locates and loads the BL2 raw binary image in the trusted SRAM.
+ * Called by the primary cpu after a cold boot.
+ * TODO: Add support for alternative image load mechanism e.g using virtio/elf
+ * loader etc.
+ ******************************************************************************/
+void bl1_load_bl2(void)
+{
+	image_desc_t *image_desc;
+	image_info_t *image_info;
+	entry_point_info_t *ep_info;
+	meminfo_t *bl1_tzram_layout;
+	meminfo_t *bl2_tzram_layout;
+	int err;
+
+	/* Get the image descriptor */
+	image_desc = bl1_plat_get_image_desc(BL2_IMAGE_ID);
+	assert(image_desc);
+
+	/* Get the image info */
+	image_info = &image_desc->image_info;
+
+	/* Get the entry point info */
+	ep_info = &image_desc->ep_info;
 
 	/* Find out how much free trusted ram remains after BL1 load */
 	bl1_tzram_layout = bl1_plat_sec_mem_layout();
 
 	INFO("BL1: Loading BL2\n");
 
-#if TRUSTED_BOARD_BOOT
-	/* Initialize authentication module */
-	auth_mod_init();
-#endif /* TRUSTED_BOARD_BOOT */
-
 	/* Load the BL2 image */
 	err = load_auth_image(bl1_tzram_layout,
 			 BL2_IMAGE_ID,
-			 BL2_BASE,
-			 &bl2_image_info,
-			 &bl2_ep);
+			 image_info->image_base,
+			 image_info,
+			 ep_info);
 
 	if (err) {
 		ERROR("Failed to load BL2 firmware.\n");
@@ -188,11 +189,10 @@ void bl1_main(void)
 	bl2_tzram_layout = (meminfo_t *) bl1_tzram_layout->free_base;
 	bl1_init_bl2_mem_layout(bl1_tzram_layout, bl2_tzram_layout);
 
-	bl1_plat_set_bl2_ep_info(&bl2_image_info, &bl2_ep);
-	bl2_ep.args.arg1 = (unsigned long)bl2_tzram_layout;
-	bl1_run_bl2(&bl2_ep);
-
-	return;
+	ep_info->args.arg1 = (unsigned long)bl2_tzram_layout;
+	NOTICE("BL1: Booting BL2\n");
+	VERBOSE("BL1: BL2 memory layout address = 0x%llx\n",
+		(unsigned long long) bl2_tzram_layout);
 }
 
 /*******************************************************************************

bl1/bl1_private.h

@@ -46,4 +46,5 @@ extern uint64_t __BL1_RAM_END__;
 void bl1_arch_setup(void);
 void bl1_arch_next_el_setup(void);
 
+void bl1_prepare_next_image(unsigned int image_id);
 #endif /* __BL1_PRIVATE_H__ */

include/common/bl_common.h

 /*
- * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2015, 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:
@@ -59,11 +59,41 @@
 #define ENTRY_POINT_INFO_PC_OFFSET	0x08
 #define ENTRY_POINT_INFO_ARGS_OFFSET	0x18
 
-#define PARAM_EP_SECURITY_MASK    0x1
+/* The following are used to set/get image attributes. */
+#define EXECUTABLE			(0x1)
+#define NON_EXECUTABLE			(0x0)
+#define PARAM_EP_EXECUTE_MASK		(0x1)
+#define PARAM_EP_EXECUTE_SHIFT		(0x1)
+#define PARAM_EP_SECURITY_MASK		(0x1)
+#define PARAM_EP_SECURITY_SHIFT		(0x0)
+
 #define GET_SECURITY_STATE(x) (x & PARAM_EP_SECURITY_MASK)
 #define SET_SECURITY_STATE(x, security) \
 			((x) = ((x) & ~PARAM_EP_SECURITY_MASK) | (security))
 
+#define GET_EXEC_STATE(x)    \
+    (((x) >> PARAM_EP_EXECUTE_SHIFT) & PARAM_EP_EXECUTE_MASK)
+
+#define SET_EXEC_STATE(x)    \
+    (((x) & PARAM_EP_EXECUTE_MASK) << PARAM_EP_EXECUTE_SHIFT)
+
+#define GET_SEC_STATE(x)    \
+    (((x) >> PARAM_EP_SECURITY_SHIFT) & PARAM_EP_SECURITY_MASK)
+
+#define SET_SEC_STATE(x)    \
+    (((x) & PARAM_EP_SECURITY_MASK) << PARAM_EP_SECURITY_SHIFT)
+
+/*
+ * The following are used for image state attributes.
+ * Image can only be in one of the following state.
+ */
+#define IMAGE_STATE_RESET			0
+#define IMAGE_STATE_COPIED			1
+#define IMAGE_STATE_COPYING			2
+#define IMAGE_STATE_AUTHENTICATED		3
+#define IMAGE_STATE_EXECUTED			4
+#define IMAGE_STATE_INTERRUPTED			5
+
 #define EP_EE_MASK	0x2
 #define EP_EE_LITTLE	0x0
 #define EP_EE_BIG	0x2
@@ -82,6 +112,8 @@
 
 #define VERSION_1		0x01
 
+#define INVALID_IMAGE_ID		(0xFFFFFFFF)
+
 #define SET_PARAM_HEAD(_p, _type, _ver, _attr) do { \
 	(_p)->h.type = (uint8_t)(_type); \
 	(_p)->h.version = (uint8_t)(_ver); \
@@ -196,8 +228,24 @@ typedef struct image_info {
 	param_header_t h;
 	uintptr_t image_base;   /* physical address of base of image */
 	uint32_t image_size;    /* bytes read from image file */
+	uint32_t copied_size;	/* image size copied in blocks */
 } image_info_t;
 
+/*****************************************************************************
+ * The image descriptor struct definition.
+ *****************************************************************************/
+typedef struct image_desc {
+	/* Contains unique image id for the image. */
+	unsigned int image_id;
+	image_info_t image_info;
+	entry_point_info_t ep_info;
+	/*
+	 * This member contains Image state information.
+	 * Refer IMAGE_STATE_XXX defined above.
+	 */
+	unsigned int state;
+} image_desc_t;
+
 /*******************************************************************************
  * This structure represents the superset of information that can be passed to
  * BL31 e.g. while passing control to it from BL2. The BL32 parameters will be

include/common/el3_common_macros.S

@@ -247,13 +247,11 @@
 #endif
 	.endif /* _init_c_runtime */
 
-#if IMAGE_BL31
 	/* ---------------------------------------------------------------------
 	 * Use SP_EL0 for the C runtime stack.
 	 * ---------------------------------------------------------------------
 	 */
 	msr	spsel, #0
-#endif /* IMAGE_BL31 */
 
 	/* ---------------------------------------------------------------------
 	 * Allocate a stack whose memory will be marked as Normal-IS-WBWA when

include/plat/common/common_def.h

@@ -30,6 +30,9 @@
 #ifndef __COMMON_DEF_H__
 #define __COMMON_DEF_H__
 
+#include <bl_common.h>
+#include <platform_def.h>
+
 /******************************************************************************
  * Required platform porting definitions that are expected to be common to
  * all platforms
@@ -74,5 +77,14 @@
  */
 #define __warn_deprecated	__attribute__ ((deprecated))
 
+#define BL2_IMAGE_DESC {				\
+	.image_id = BL2_IMAGE_ID,			\
+	.image_info.h.version = VERSION_1,		\
+	.image_info.h.attr = SET_EXEC_STATE(EXECUTABLE),\
+	.image_info.image_base = BL2_BASE,		\
+	.ep_info.h.attr = SET_SEC_STATE(SECURE),	\
+	.ep_info.pc = BL2_BASE				\
+}
+
 #endif /* __COMMON_DEF_H__ */
 

include/plat/common/platform.h

@@ -43,6 +43,7 @@ struct meminfo;
 struct image_info;
 struct entry_point_info;
 struct bl31_params;
+struct image_desc;
 
 /*******************************************************************************
  * plat_get_rotpk_info() flags
@@ -91,18 +92,18 @@ void bl1_plat_arch_setup(void);
 void bl1_platform_setup(void);
 struct meminfo *bl1_plat_sec_mem_layout(void);
 
-/*
- * This function allows the platform to change the entrypoint information for
- * BL2, after BL1 has loaded BL2 into memory but before BL2 is executed.
- */
-void bl1_plat_set_bl2_ep_info(struct image_info *image,
-			      struct entry_point_info *ep);
-
 /*******************************************************************************
  * Optional BL1 functions (may be overridden)
  ******************************************************************************/
 void bl1_init_bl2_mem_layout(const struct meminfo *bl1_mem_layout,
 			     struct meminfo *bl2_mem_layout);
+/*
+ * The following functions are used for image loading process in BL1.
+ */
+void bl1_plat_set_ep_info(unsigned int image_id,
+		struct entry_point_info *ep_info);
+unsigned int bl1_plat_get_next_image_id(void);
+struct image_desc *bl1_plat_get_image_desc(unsigned int image_id);
 
 /*******************************************************************************
  * Mandatory BL2 functions

plat/arm/common/arm_bl1_setup.c

@@ -57,7 +57,6 @@
 #pragma weak bl1_plat_arch_setup
 #pragma weak bl1_platform_setup
 #pragma weak bl1_plat_sec_mem_layout
-#pragma weak bl1_plat_set_bl2_ep_info
 
 
 /* Data structure which holds the extents of the trusted SRAM for BL1*/
@@ -169,16 +168,3 @@ void bl1_plat_prepare_exit(entry_point_info_t *ep_info)
 	sev();
 #endif
 }
-
-/*******************************************************************************
- * Before calling this function BL2 is loaded in memory and its entrypoint
- * is set by load_image. This is a placeholder for the platform to change
- * the entrypoint of BL2 and set SPSR and security state.
- * On ARM standard platforms we only set the security state of the entrypoint
- ******************************************************************************/
-void bl1_plat_set_bl2_ep_info(image_info_t *bl2_image,
-				entry_point_info_t *bl2_ep)
-{
-	SET_SECURITY_STATE(bl2_ep->h.attr, SECURE);
-	bl2_ep->spsr = SPSR_64(MODE_EL1, MODE_SP_ELX, DISABLE_ALL_EXCEPTIONS);
-}

plat/common/plat_bl1_common.c

+/*
+ * Copyright (c) 2015, 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:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <bl_common.h>
+#include <debug.h>
+#include <platform_def.h>
+
+/*
+ * The following platform functions are weakly defined. They
+ * are default implementations that allow BL1  compile in
+ * absence of real definitions. The Platforms may override
+ * with more complex definitions.
+ */
+#pragma weak bl1_plat_get_next_image_id
+#pragma weak bl1_plat_set_ep_info
+#pragma weak bl1_plat_get_image_desc
+
+
+unsigned int bl1_plat_get_next_image_id(void)
+{
+	/* BL2 load will be done by default. */
+	return BL2_IMAGE_ID;
+}
+
+void bl1_plat_set_ep_info(unsigned int image_id,
+		entry_point_info_t *ep_info)
+{
+
+}
+
+/*
+ * Following is the default definition that always
+ * returns BL2 image details.
+ */
+image_desc_t *bl1_plat_get_image_desc(unsigned int image_id)
+{
+	static image_desc_t bl2_img_desc = BL2_IMAGE_DESC;
+	return &bl2_img_desc;
+}