cmake: support ELF image adjustment

This commit adds support for adjust the addresses of the final image.
This is useful when the image is to be flashed at a location different
from the LMA address encoded in the ELF file by the linker.

An example use-case is multicore systems where core A might load image
from a flash partition into RAM in order for core B to execute and load,
but where the image itself is build with the RAM addresses as LMA.

It updates the zephyr_image_info.h header with information of adjustment
value.

Signed-off-by: Torsten Rasmussen <[email protected]>

Author: tejlmand

CMakeLists.txt

@@ -1393,6 +1393,18 @@ if(CONFIG_OUTPUT_PRINT_MEMORY_USAGE)
   endif()
 endif()
 
+if(CONFIG_BUILD_OUTPUT_ADJUST_LMA)
+  math(EXPR adjustment "${CONFIG_BUILD_OUTPUT_ADJUST_LMA}" OUTPUT_FORMAT DECIMAL)
+  list(APPEND
+    post_build_commands
+    COMMAND $<TARGET_PROPERTY:bintools,elfconvert_command>
+            $<TARGET_PROPERTY:bintools,elfconvert_flag_final>
+            $<TARGET_PROPERTY:bintools,elfconvert_flag_lma_adjust>${adjustment}
+            $<TARGET_PROPERTY:bintools,elfconvert_flag_infile>${KERNEL_ELF_NAME}
+            $<TARGET_PROPERTY:bintools,elfconvert_flag_outfile>${KERNEL_ELF_NAME}
+    )
+endif()
+
 if(CONFIG_BUILD_OUTPUT_HEX OR BOARD_FLASH_RUNNER STREQUAL openocd)
   get_property(elfconvert_formats TARGET bintools PROPERTY elfconvert_formats)
   if(ihex IN_LIST elfconvert_formats)
@@ -1582,6 +1594,7 @@ if(CONFIG_BUILD_OUTPUT_INFO_HEADER)
     COMMAND ${PYTHON_EXECUTABLE} ${ZEPHYR_BASE}/scripts/gen_image_info.py
     --elf-file=${KERNEL_ELF_NAME}
     --header-file=${PROJECT_BINARY_DIR}/include/public/zephyr_image_info.h
+    $<$<BOOL:${adjustment}>:--adjusted-lma=${adjustment}>
     )
   list(APPEND
     post_build_byproducts

Kconfig.zephyr

@@ -494,6 +494,30 @@ config BUILD_OUTPUT_STRIPPED
 	  Build a stripped binary zephyr/zephyr.strip in the build directory.
 	  The name of this file can be customized with CONFIG_KERNEL_BIN_NAME.
 
+config BUILD_OUTPUT_ADJUST_LMA
+	string
+	help
+	  This will adjust the LMA address in the final ELF and hex files with
+	  the value provided.
+	  This will not affect the internal address symbols inside the image but
+	  can be useful when adjusting the LMA address for flash tools or multi
+	  stage loaders where a pre-loader may copy image to a second location
+	  before booting a second core.
+	  The value will be evaluated as a math expression, this means that
+	  following are valid expression
+	  - 1024
+	  - 0x1000
+	  - -0x1000
+	  - 0x20000000 - 0x10000000
+	  Note: negative numbers are valid.
+	  To adjust according to a chosen flash partition one can specify a
+	  default as:
+	  DT_CHOSEN_IMAGE_<name> := <name>,<name>-partition
+	  DT_CHOSEN_Z_FLASH := zephyr,flash
+	  config BUILD_OUTPUT_ADJUST_LMA
+	    default "$(dt_chosen_reg_addr_hex,$(DT_CHOSEN_IMAGE_M4))-\
+	             $(dt_chosen_reg_addr_hex,$(DT_CHOSEN_Z_FLASH))"
+
 config BUILD_OUTPUT_INFO_HEADER
 	bool "Create a image information header"
 	help

cmake/bintools/gnu/target_bintools.cmake

@@ -41,6 +41,8 @@ set_property(TARGET bintools PROPERTY elfconvert_flag_section_remove "--remove-s
 set_property(TARGET bintools PROPERTY elfconvert_flag_section_only "--only-section=")
 set_property(TARGET bintools PROPERTY elfconvert_flag_section_rename "--rename-section;")
 
+set_property(TARGET bintools PROPERTY elfconvert_flag_lma_adjust "--change-section-lma;*+")
+
 # Note, placing a ';' at the end results in the following param  to be a list,
 # and hence space separated.
 # Thus the command line argument becomes:

scripts/gen_image_info.py

@@ -16,21 +16,23 @@
 - Number of segments in the image
 - LMA address of each segment
 - VMA address of each segment
+- LMA adjusted of each segment if the LMA addresses has been adjusted after linking
 - Size of each segment
 '''
 
 import argparse
 from elftools.elf.elffile import ELFFile
 
 
-def write_header(filename, segments):
+def write_header(filename, segments, adjusted_lma):
     content = []
 
     filename_we = filename.split('.h')[0].upper()
     content.append(f'#ifndef {filename_we}_H')
     content.append(f'#define {filename_we}_H')
     content.append(f'')
     content.append(f'#define SEGMENT_NUM {len(segments)}')
+    content.append(f'#define ADJUSTED_LMA {adjusted_lma}')
 
     for idx, segment in enumerate(segments):
         segment_header = segment['segment'].header
@@ -69,10 +71,12 @@ def main():
                         help="""Header file to write with image data.""")
     parser.add_argument('--elf-file', required=True,
                         help="""ELF File to process.""")
+    parser.add_argument('--adjusted-lma', required=False, default=0,
+                        help="""Adjusted LMA address value.""")
     args = parser.parse_args()
 
     segments = read_segments(args.elf_file)
-    write_header(args.header_file, segments)
+    write_header(args.header_file, segments, args.adjusted_lma)
 
 
 if __name__ == "__main__":