#!/usr/bin/make -f
#
# \brief  Initcall order extraction tool for DDE Linux
# \author Stefan Kalkowski
# \date   2021-05-16
#

help:
	$(ECHO) ""
	$(ECHO) "Extracts initcall order into header file for DDE Linux"
	$(ECHO) ""
	$(ECHO) "usage:"
	$(ECHO) ""
	$(ECHO) "  extract_initcall_order <command> [VARIABLES]"
	$(ECHO) ""
	$(ECHO) "--- available commands ---"
	$(ECHO) "help        - shows this help"
	$(ECHO) "extract     - extracts initcall order to HEADER_FILE"
	$(ECHO) ""
	$(ECHO) "--- used variables ---"
	$(ECHO) "LINUX_KERNEL_DIR  - path to the Linux kernel build"
	$(ECHO) "HEADER_FILE       - path to the file that shall be generated"
	$(ECHO) ""


COMMAND := $(firstword $(MAKECMDGOALS))

SHELL        = bash
BRIGHT_COL   = \033[01;33m
DEFAULT_COL  = \033[0m
ECHO         = @echo -e


ifeq ($(COMMAND),extract)
ifeq ($(realpath $(LINUX_KERNEL_DIR)),)
$(error You have to state a valid LINUX_KERNEL_DIR, try help)
endif

ifeq ($(HEADER_FILE),)
$(error You have to state a HEADER_FILE, try help)
endif
endif

define print_file_header
echo "/*"                                                          > $(2);
echo " * \\brief  Array defining order of Linux Kernel initcalls" >> $(2);
echo " * \\author Automatically generated file - do no edit"      >> $(2);
echo " * \\date   $(1)"                                           >> $(2);
echo " */"                                                        >> $(2);
echo ""                                                           >> $(2);
echo "#pragma once"                                               >> $(2);
echo ""                                                           >> $(2);
echo "static const char * lx_emul_initcall_order[] = {"           >> $(2);
endef

define print_symbol
echo "	\"$(1)\"," >> $(2);
endef

define print_file_footer
echo "	\"END_OF_INITCALL_ORDER_ARRAY_DUMMY_ENTRY\"" >> $(1);
echo "};" >> $(1);
endef

#
# Linux 5.12 upwards generates data symbols featuring an '__initcall_id'
# including a counter value and __LINE__ information. Discard this information
# when collecting the 'lx_emul_initcall_order'.
#
strip_kmod_prefix = sed "s/__initcall__.*__[0-9]\+_[0-9]\+/__initcall/"

INITCALLS = $(shell grep -i "^[0-9a-f]* [td] __initcall_" $(LINUX_KERNEL_DIR)/System.map |\
                    $(strip_kmod_prefix) |\
                    awk '{print $$3}')

extract:
	@$(call print_file_header,$(shell date +"%F"),$(HEADER_FILE))
	@$(foreach sym,$(INITCALLS),$(call print_symbol,$(sym),$(HEADER_FILE)))
	@$(call print_file_footer,$(HEADER_FILE))


.PHONY: extract help