# SPDX-License-Identifier: GPL-2.0# ===========================================================================# Module versions# ===========================================================================## Stage one of module building created the following:# a) The individual .o files used for the module# b) A <module>.o file which is the .o files above linked together# c) A <module>.mod file, listing the name of the preliminary <module>.o file,#    plus all .o files# d) modules.order, which lists all the modules # Stage 2 is handled by this file and does the following# 1) Find all modules listed in modules.order# 2) modpost is then used to# 3)  create one <module>.mod.c file pr. module# 4)  create one Module.symvers file with CRC for all exported symbols # Step 3 is used to place certain information in the module's ELF# section, including information such as:#   Version magic (see include/linux/vermagic.h for full details)#     - Kernel release#     - SMP is CONFIG_SMP#     - PREEMPT is CONFIG_PREEMPT[_RT]#     - GCC Version#   Module info#     - Module version (MODULE_VERSION)#     - Module alias'es (MODULE_ALIAS)#     - Module license (MODULE_LICENSE)#     - See include/linux/module.h for more details # Step 4 is solely used to allow module versioning in external modules,# where the CRC of each module is retrieved from the Module.symvers file. # KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined# symbols in the final module linking stage# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.# This is solely useful to speed up test compiles PHONY := __modpost__modpost: include include/config/auto.confinclude scripts/Kbuild.include # for ld_flagsinclude scripts/Makefile.lib MODPOST = scripts/mod/modpost								\	$(if $(CONFIG_MODVERSIONS),-m)							\	$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a)					\	$(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E)					\	$(if $(KBUILD_MODPOST_WARN),-w) \	-o $@ ifdef MODPOST_VMLINUX quiet_cmd_modpost = MODPOST $@      cmd_modpost = $(MODPOST) $< vmlinux.symvers: vmlinux.o	$(call cmd,modpost) __modpost: vmlinux.symvers else ifeq ($(KBUILD_EXTMOD),) input-symdump := vmlinux.symversoutput-symdump := Module.symvers else # set src + obj - they may be used in the modules's Makefileobj := $(KBUILD_EXTMOD)src := $(obj) # Include the module's Makefile to find KBUILD_EXTRA_SYMBOLSinclude $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \             $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile) # modpost option for external modulesMODPOST += -e input-symdump := Module.symvers $(KBUILD_EXTRA_SYMBOLS)output-symdump := $(KBUILD_EXTMOD)/Module.symvers endif # modpost options for modules (both in-kernel and external)MODPOST += \	$(addprefix -i ,$(wildcard $(input-symdump))) \	$(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \	$(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) # 'make -i -k' ignores compile errors, and builds as many modules as possible.ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)MODPOST += -nendif # Clear VPATH to not search for *.symvers in $(srctree). Check only $(objtree).VPATH :=$(input-symdump):	@echo >&2 'WARNING: Symbol version dump "$@" is missing.'	@echo >&2 '         Modules may not have dependencies or modversions.' ifdef CONFIG_LTO_CLANG# With CONFIG_LTO_CLANG, .o files might be LLVM bitcode, so we need to run# LTO to compile them into native code before running modpostprelink-ext := .lto quiet_cmd_cc_lto_link_modules = LTO [M] $@cmd_cc_lto_link_modules =						\	$(LD) $(ld_flags) -r -o $@					\		$(shell [ -s $(@:.lto.o=.o.symversions) ] &&		\			echo -T $(@:.lto.o=.o.symversions))		\		--whole-archive $^ %.lto.o: %.o	$(call if_changed,cc_lto_link_modules)endif modules := $(sort $(shell cat $(MODORDER))) # Read out modules.order to pass in modpost.# Otherwise, allmodconfig would fail with "Argument list too long".quiet_cmd_modpost = MODPOST $@      cmd_modpost = sed 's/\.ko$$/$(prelink-ext)\.o/' $< | $(MODPOST) -T - $(output-symdump): $(MODORDER) $(input-symdump) $(modules:.ko=$(prelink-ext).o) FORCE	$(call if_changed,modpost) targets += $(output-symdump) __modpost: $(output-symdump)ifneq ($(KBUILD_MODPOST_NOFINAL),1)	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinalendif PHONY += FORCEFORCE: existing-targets := $(wildcard $(sort $(targets))) -include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) endif .PHONY: $(PHONY)