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 $(objtree)/include/config/auto.conf 39include $(srctree)/scripts/Kbuild.include 40 41MODPOST = $(objtree)/scripts/mod/modpost 42 43modpost-args = \ 44 $(if $(CONFIG_MODULES),-M) \ 45 $(if $(CONFIG_MODVERSIONS),-m) \ 46 $(if $(CONFIG_EXTENDED_MODVERSIONS),-x) \ 47 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \ 48 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \ 49 $(if $(KBUILD_MODPOST_WARN),-w) \ 50 $(if $(KBUILD_NSDEPS),-d modules.nsdeps) \ 51 $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) \ 52 $(if $(findstring 1, $(KBUILD_EXTRA_WARN)),-W) \ 53 -o $@ 54 55modpost-deps := $(MODPOST) 56 57# 'make -i -k' ignores compile errors, and builds as many modules as possible. 58ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),) 59modpost-args += -n 60endif 61 62# Read out modules.order to pass in modpost. 63# Otherwise, allmodconfig would fail with "Argument list too long". 64ifdef KBUILD_MODULES 65modpost-args += -T modules.order 66modpost-deps += modules.order 67endif 68 69ifeq ($(KBUILD_EXTMOD),) 70 71# Generate the list of in-tree objects in vmlinux 72# --------------------------------------------------------------------------- 73 74# This is used to retrieve symbol versions generated by genksyms. 75ifdef CONFIG_MODVERSIONS 76vmlinux.symvers Module.symvers: .vmlinux.objs 77endif 78 79# Ignore libgcc.a 80# Some architectures do '$(CC) --print-libgcc-file-name' to borrow libgcc.a 81# from the toolchain, but there is no EXPORT_SYMBOL in it. 82 83quiet_cmd_vmlinux_objs = GEN $@ 84 cmd_vmlinux_objs = \ 85 for f in $(real-prereqs); do \ 86 case $${f} in \ 87 *libgcc.a) ;; \ 88 *) $(AR) t $${f} ;; \ 89 esac \ 90 done > $@ 91 92targets += .vmlinux.objs 93.vmlinux.objs: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE 94 $(call if_changed,vmlinux_objs) 95 96ifdef CONFIG_TRIM_UNUSED_KSYMS 97ksym-wl := $(CONFIG_UNUSED_KSYMS_WHITELIST) 98ksym-wl := $(if $(filter-out /%, $(ksym-wl)),$(if $(wildcard $(ksym-wl)),,$(srctree)/))$(ksym-wl) 99modpost-args += -t $(addprefix -u , $(ksym-wl)) 100modpost-deps += $(ksym-wl) 101endif 102 103ifeq ($(wildcard vmlinux.o),) 104missing-input := vmlinux.o 105output-symdump := modules-only.symvers 106else 107modpost-args += vmlinux.o 108modpost-deps += vmlinux.o 109output-symdump := $(if $(KBUILD_MODULES), Module.symvers, vmlinux.symvers) 110endif 111 112else 113 114# set src + obj - they may be used in the modules's Makefile 115obj := . 116src := $(srcroot) 117 118# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS 119include $(kbuild-file) 120 121output-symdump := Module.symvers 122 123ifeq ($(wildcard $(objtree)/Module.symvers),) 124missing-input := $(objtree)/Module.symvers 125else 126modpost-args += -i $(objtree)/Module.symvers 127modpost-deps += $(objtree)/Module.symvers 128endif 129 130modpost-args += -e $(addprefix -i , $(KBUILD_EXTRA_SYMBOLS)) 131 132endif # ($(KBUILD_EXTMOD),) 133 134quiet_cmd_modpost = MODPOST $@ 135 cmd_modpost = \ 136 $(if $(missing-input), \ 137 echo >&2 "WARNING: $(missing-input) is missing."; \ 138 echo >&2 " Modules may not have dependencies or modversions."; \ 139 echo >&2 " You may get many unresolved symbol errors."; \ 140 echo >&2 " You can set KBUILD_MODPOST_WARN=1 to turn errors into warning"; \ 141 echo >&2 " if you want to proceed at your own risk.";) \ 142 $(MODPOST) $(modpost-args) 143 144targets += $(output-symdump) 145$(output-symdump): $(modpost-deps) FORCE 146 $(call if_changed,modpost) 147 148__modpost: $(output-symdump) 149PHONY += FORCE 150FORCE: 151 152existing-targets := $(wildcard $(sort $(targets))) 153 154-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 155 156.PHONY: $(PHONY) 157