1# SPDX-License-Identifier: GPL-2.0 2# =========================================================================== 3# Module versions 4# =========================================================================== 5# 6# Stage one of module building created the following: 7# a) The individual .o files used for the module 8# b) A <module>.o file which is the .o files above linked together 9# c) A <module>.mod file, listing the name of the preliminary <module>.o file, 10# plus all .o files 11# d) modules.order, which lists all the modules 12 13# Stage 2 is handled by this file and does the following 14# 1) Find all modules listed in modules.order 15# 2) modpost is then used to 16# 3) create one <module>.mod.c file per module 17# 4) create one Module.symvers file with CRC for all exported symbols 18 19# Step 3 is used to place certain information in the module's ELF 20# section, including information such as: 21# Version magic (see include/linux/vermagic.h for full details) 22# - Kernel release 23# - SMP is CONFIG_SMP 24# - PREEMPT is CONFIG_PREEMPT[_RT] 25# - GCC Version 26# Module info 27# - Module version (MODULE_VERSION) 28# - Module alias'es (MODULE_ALIAS) 29# - Module license (MODULE_LICENSE) 30# - See include/linux/module.h for more details 31 32# Step 4 is solely used to allow module versioning in external modules, 33# where the CRC of each module is retrieved from the Module.symvers file. 34 35PHONY := __modpost 36__modpost: 37 38include include/config/auto.conf 39include $(srctree)/scripts/Kbuild.include 40 41modpost-args = \ 42 $(if $(CONFIG_MODVERSIONS),-m) \ 43 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \ 44 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \ 45 $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \ 46 $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) \ 47 -o $@ 48 49# 'make -i -k' ignores compile errors, and builds as many modules as possible. 50ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),) 51modpost-args += -n 52endif 53 54ifeq ($(KBUILD_EXTMOD),) 55 56# Generate the list of in-tree objects in vmlinux 57# --------------------------------------------------------------------------- 58 59# This is used to retrieve symbol versions generated by genksyms. 60ifdef CONFIG_MODVERSIONS 61vmlinux.symvers Module.symvers: .vmlinux.objs 62endif 63 64# Ignore libgcc.a 65# Some architectures do '$(CC) --print-libgcc-file-name' to borrow libgcc.a 66# from the toolchain, but there is no EXPORT_SYMBOL in it. 67 68quiet_cmd_vmlinux_objs = GEN $@ 69 cmd_vmlinux_objs = \ 70 for f in $(real-prereqs); do \ 71 case $${f} in \ 72 *libgcc.a) ;; \ 73 *) $(AR) t $${f} ;; \ 74 esac \ 75 done > $@ 76 77targets += .vmlinux.objs 78.vmlinux.objs: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE 79 $(call if_changed,vmlinux_objs) 80 81vmlinux.o-if-present := $(wildcard vmlinux.o) 82output-symdump := vmlinux.symvers 83 84ifdef KBUILD_MODULES 85output-symdump := $(if $(vmlinux.o-if-present), Module.symvers, modules-only.symvers) 86missing-input := $(filter-out $(vmlinux.o-if-present),vmlinux.o) 87endif 88 89else 90 91# set src + obj - they may be used in the modules's Makefile 92obj := $(KBUILD_EXTMOD) 93src := $(obj) 94 95# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS 96include $(or $(wildcard $(src)/Kbuild), $(src)/Makefile) 97 98module.symvers-if-present := $(wildcard Module.symvers) 99output-symdump := $(KBUILD_EXTMOD)/Module.symvers 100missing-input := $(filter-out $(module.symvers-if-present), Module.symvers) 101 102modpost-args += -e $(addprefix -i ,$(module.symvers-if-present) $(KBUILD_EXTRA_SYMBOLS)) 103 104endif # ($(KBUILD_EXTMOD),) 105 106ifneq ($(KBUILD_MODPOST_WARN)$(missing-input),) 107modpost-args += -w 108endif 109 110modorder-if-needed := $(if $(KBUILD_MODULES), $(MODORDER)) 111 112MODPOST = scripts/mod/modpost 113 114# Read out modules.order to pass in modpost. 115# Otherwise, allmodconfig would fail with "Argument list too long". 116quiet_cmd_modpost = MODPOST $@ 117 cmd_modpost = \ 118 $(if $(missing-input), \ 119 echo >&2 "WARNING: $(missing-input) is missing."; \ 120 echo >&2 " Modules may not have dependencies or modversions."; \ 121 echo >&2 " You may get many unresolved symbol warnings.";) \ 122 sed 's/ko$$/o/' $(or $(modorder-if-needed), /dev/null) | $(MODPOST) $(modpost-args) -T - $(vmlinux.o-if-present) 123 124targets += $(output-symdump) 125$(output-symdump): $(modorder-if-needed) $(vmlinux.o-if-present) $(module.symvers-if-present) $(MODPOST) FORCE 126 $(call if_changed,modpost) 127 128__modpost: $(output-symdump) 129PHONY += FORCE 130FORCE: 131 132existing-targets := $(wildcard $(sort $(targets))) 133 134-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 135 136.PHONY: $(PHONY) 137