# 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 per 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. PHONY := __modpost__modpost: include include/config/auto.confinclude $(srctree)/scripts/Kbuild.include modpost-args =										\	$(if $(CONFIG_MODVERSIONS),-m)							\	$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a)					\	$(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E)					\	$(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS))					\	$(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N)	\	-o $@ # 'make -i -k' ignores compile errors, and builds as many modules as possible.ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)modpost-args += -nendif ifeq ($(KBUILD_EXTMOD),) # Generate the list of in-tree objects in vmlinux# --------------------------------------------------------------------------- # This is used to retrieve symbol versions generated by genksyms.ifdef CONFIG_MODVERSIONSvmlinux.symvers Module.symvers: .vmlinux.objsendif # Ignore libgcc.a# Some architectures do '$(CC) --print-libgcc-file-name' to borrow libgcc.a# from the toolchain, but there is no EXPORT_SYMBOL in it. quiet_cmd_vmlinux_objs = GEN     $@      cmd_vmlinux_objs =		\	for f in $(real-prereqs); do	\		case $${f} in		\		*libgcc.a) ;;		\		*) $(AR) t $${f} ;;	\		esac			\	done > $@ targets += .vmlinux.objs.vmlinux.objs: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE	$(call if_changed,vmlinux_objs) vmlinux.o-if-present := $(wildcard vmlinux.o)output-symdump := vmlinux.symvers ifdef KBUILD_MODULESoutput-symdump := $(if $(vmlinux.o-if-present), Module.symvers, modules-only.symvers)missing-input := $(filter-out $(vmlinux.o-if-present),vmlinux.o)endif 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 $(or $(wildcard $(src)/Kbuild), $(src)/Makefile) module.symvers-if-present := $(wildcard Module.symvers)output-symdump := $(KBUILD_EXTMOD)/Module.symversmissing-input := $(filter-out $(module.symvers-if-present), Module.symvers) modpost-args += -e $(addprefix -i ,$(module.symvers-if-present) $(KBUILD_EXTRA_SYMBOLS)) endif # ($(KBUILD_EXTMOD),) ifneq ($(KBUILD_MODPOST_WARN)$(missing-input),)modpost-args += -wendif modorder-if-needed := $(if $(KBUILD_MODULES), $(MODORDER)) MODPOST = scripts/mod/modpost # Read out modules.order to pass in modpost.# Otherwise, allmodconfig would fail with "Argument list too long".quiet_cmd_modpost = MODPOST $@      cmd_modpost = \	$(if $(missing-input), \		echo >&2 "WARNING: $(missing-input) is missing."; \		echo >&2 "         Modules may not have dependencies or modversions."; \		echo >&2 "         You may get many unresolved symbol warnings.";) \	sed 's/ko$$/o/' $(or $(modorder-if-needed), /dev/null) | $(MODPOST) $(modpost-args) -T - $(vmlinux.o-if-present) targets += $(output-symdump)$(output-symdump): $(modorder-if-needed) $(vmlinux.o-if-present) $(module.symvers-if-present) $(MODPOST) FORCE	$(call if_changed,modpost) __modpost: $(output-symdump)PHONY += FORCEFORCE: existing-targets := $(wildcard $(sort $(targets))) -include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) .PHONY: $(PHONY)