kernel: init.c: Added required hooks for the relocation

This patch splits the text section into 2 parts. The first section
will have some info regarding vector tables and debug info. The
second section will have the complete text section.
This is needed to force the required functions and data variables
the correct locations.
This is due to the behavior of the linker. The linker will only link
once and hence this text section had to be split to make room
for the generated linker script.

Added a new Kconfig CODE_DATA_RELOCATION which when enabled will
invoke the script, which does the required relocation.

Added hooks inside init.c for bss zeroing and data copy operations.
Needed when we have to copy data from ROM to required memory type.

Signed-off-by: Adithya Baglody <adithya.nagaraj.baglody@intel.com>

Kconfig.zephyr

@@ -69,6 +69,15 @@ config LINKER_ORPHAN_SECTION_ERROR
 
 endchoice
 
+config CODE_DATA_RELOCATION
+       bool "Relocate code/data sections"
+       depends on ARM
+       help
+	  When selected this will relocate .text, data and .bss sections from
+	  the specified files and places it in the required memory region. The
+	  files should be specified in the CMakeList.txt file with
+	  a cmake API zephyr_code_relocation().
+
 config HAS_FLASH_LOAD_OFFSET
 	bool
 	help

include/arch/arm/cortex_m/scripts/linker.ld

@@ -161,6 +161,16 @@ SECTIONS
 	KEEP(*(".kinetis_flash_config.*"))
 
 	_vector_end = .;
+	} GROUP_LINK_IN(ROMABLE_REGION)
+
+#ifdef CONFIG_CODE_DATA_RELOCATION
+
+#include <linker_relocate.ld>
+
+#endif /* CONFIG_CODE_DATA_RELOCATION */
+
+    SECTION_PROLOGUE(_TEXT_SECTION_NAME_2,,)
+	{
 	_image_text_start = .;
 	*(.text)
 	*(".text.*")

kernel/init.c

@@ -147,6 +147,11 @@ void _bss_zero(void)
 	(void)memset(&__ccm_bss_start, 0,
 		     ((u32_t) &__ccm_bss_end - (u32_t) &__ccm_bss_start));
 #endif
+#ifdef CONFIG_CODE_DATA_RELOCATION
+	extern void bss_zeroing_relocation(void);
+
+	bss_zeroing_relocation();
+#endif	/* CONFIG_CODE_DATA_RELOCATION */
 #ifdef CONFIG_APPLICATION_MEMORY
 	(void)memset(&__app_bss_start, 0,
 		     ((u32_t) &__app_bss_end - (u32_t) &__app_bss_start));
@@ -171,6 +176,11 @@ void _data_copy(void)
 	(void)memcpy(&__ccm_data_start, &__ccm_data_rom_start,
 		 ((u32_t) &__ccm_data_end - (u32_t) &__ccm_data_start));
 #endif
+#ifdef CONFIG_CODE_DATA_RELOCATION
+	extern void data_copy_xip_relocation(void);
+
+	data_copy_xip_relocation();
+#endif	/* CONFIG_CODE_DATA_RELOCATION */
 #ifdef CONFIG_APP_SHARED_MEM
 	(void)memcpy(&_app_smem_start, &_app_smem_rom_start,
 		 ((u32_t) &_app_smem_end - (u32_t) &_app_smem_start));