scripts: add dump_init_order.py

Add a dump_init_order.py script to dump a human readable list of init
function and device structs in linking order. This can be useful for
troubleshooting priority change breakages due to unclear interactions
between SYS_INIT and devices or devices declared with DEVICE_DEFINE.

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>

scripts/dump_init_order.py

@@ -0,0 +1,117 @@
+#!/usr/bin/env python3
+
+# Copyright 2023 Google LLC
+# SPDX-License-Identifier: Apache-2.0
+
+"""
+Dump the initlevel and device_area in a human readable format.
+"""
+
+import argparse
+import sys
+
+from elftools.elf.elffile import ELFFile
+from elftools.elf.relocation import Section
+from elftools.elf.sections import SymbolTableSection
+
+def _parse_args(argv):
+    """Parse the command line arguments."""
+    parser = argparse.ArgumentParser(
+        description=__doc__,
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+        allow_abbrev=False)
+
+    parser.add_argument("-f", "--elf-file", default="build/zephyr/zephyr.elf",
+                        help="ELF file to use")
+    return parser.parse_args(argv)
+
+
+def load_objects(elf):
+    """Initialize the object table."""
+    objects = {}
+
+    for section in elf.iter_sections():
+        if not isinstance(section, SymbolTableSection):
+            continue
+
+        for sym in section.iter_symbols():
+            if (sym.name and
+                sym.entry.st_size > 0 and
+                sym.entry.st_info.type in ["STT_OBJECT", "STT_FUNC"]):
+                objects[sym.entry.st_value] = (sym.name, sym.entry.st_size)
+
+    return objects
+
+
+def _print_initlevel(section, objects):
+    size = section.header.sh_size
+    base_addr = section.header.sh_addr
+    offset = 0
+    data = section.data()
+
+    print("initlevel:")
+
+    while offset < size:
+        addr = base_addr + offset
+        if addr not in objects:
+            print(f"no symbol at addr {addr:08x}")
+        obj = objects[addr]
+
+        arg0 = int.from_bytes(data[offset:offset+4], byteorder='little')
+        arg1 = int.from_bytes(data[offset+4:offset+8], byteorder='little')
+
+        if arg0 in objects:
+            arg0s = objects[arg0][0]
+        else:
+            arg0s = "unknown"
+
+        if not arg1:
+            arg1s = "NULL"
+        elif arg1 in objects:
+            arg1s = objects[arg1][0]
+        else:
+            arg1s = "unknown"
+
+        print(f"  {obj[0]}({arg0s}, {arg1s})")
+        offset += obj[1]
+
+
+def _print_device_area(section, objects):
+    size = section.header.sh_size
+    base_addr = section.header.sh_addr
+    offset = 0
+
+    print("device_area:")
+
+    while offset < size:
+        addr = base_addr + offset
+        if addr not in objects:
+            print(f"no symbol at addr {addr:08x}")
+        obj = objects[addr]
+
+        print(f"  {obj[0]}")
+        offset += obj[1]
+
+
+def main(argv=None):
+    args = _parse_args(argv)
+
+    print(f"Working on: {args.elf_file}")
+
+    elf = ELFFile(open(args.elf_file, "rb"))
+    objects = load_objects(elf)
+
+    for section in elf.iter_sections():
+        if not isinstance(section, Section):
+            continue
+
+        if section.name == "initlevel":
+            _print_initlevel(section, objects)
+        elif section.name == "device_area":
+            _print_device_area(section, objects)
+
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv[1:]))