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 pr. 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 35# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined 36# symbols in the final module linking stage 37# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules. 38# This is solely useful to speed up test compiles 39 40PHONY := __modpost 41__modpost: 42 43include include/config/auto.conf 44include scripts/Kbuild.include 45 46# for ld_flags 47include scripts/Makefile.lib 48 49MODPOST = scripts/mod/modpost \ 50 $(if $(CONFIG_MODVERSIONS),-m) \ 51 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \ 52 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \ 53 $(if $(KBUILD_MODPOST_WARN),-w) \ 54 -o $@ 55 56ifdef MODPOST_VMLINUX 57 58quiet_cmd_modpost = MODPOST $@ 59 cmd_modpost = $(MODPOST) $< 60 61vmlinux.symvers: vmlinux.o 62 $(call cmd,modpost) 63 64__modpost: vmlinux.symvers 65 66else 67 68ifeq ($(KBUILD_EXTMOD),) 69 70input-symdump := vmlinux.symvers 71output-symdump := modules-only.symvers 72 73quiet_cmd_cat = GEN $@ 74 cmd_cat = cat $(real-prereqs) > $@ 75 76ifneq ($(wildcard vmlinux.symvers),) 77 78__modpost: Module.symvers 79Module.symvers: vmlinux.symvers modules-only.symvers FORCE 80 $(call if_changed,cat) 81 82targets += Module.symvers 83 84endif 85 86else 87 88# set src + obj - they may be used in the modules's Makefile 89obj := $(KBUILD_EXTMOD) 90src := $(obj) 91 92# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS 93include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \ 94 $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile) 95 96# modpost option for external modules 97MODPOST += -e 98 99input-symdump := Module.symvers $(KBUILD_EXTRA_SYMBOLS) 100output-symdump := $(KBUILD_EXTMOD)/Module.symvers 101 102endif 103 104# modpost options for modules (both in-kernel and external) 105MODPOST += \ 106 $(addprefix -i ,$(wildcard $(input-symdump))) \ 107 $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \ 108 $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) 109 110# 'make -i -k' ignores compile errors, and builds as many modules as possible. 111ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),) 112MODPOST += -n 113endif 114 115# Clear VPATH to not search for *.symvers in $(srctree). Check only $(objtree). 116VPATH := 117$(input-symdump): 118 @echo >&2 'WARNING: Symbol version dump "$@" is missing.' 119 @echo >&2 ' Modules may not have dependencies or modversions.' 120 121ifdef CONFIG_LTO_CLANG 122# With CONFIG_LTO_CLANG, .o files might be LLVM bitcode, so we need to run 123# LTO to compile them into native code before running modpost 124prelink-ext := .lto 125 126quiet_cmd_cc_lto_link_modules = LTO [M] $@ 127cmd_cc_lto_link_modules = \ 128 $(LD) $(ld_flags) -r -o $@ \ 129 $(shell [ -s $(@:.lto.o=.o.symversions) ] && \ 130 echo -T $(@:.lto.o=.o.symversions)) \ 131 --whole-archive $^ 132 133%.lto.o: %.o 134 $(call if_changed,cc_lto_link_modules) 135endif 136 137modules := $(sort $(shell cat $(MODORDER))) 138 139# Read out modules.order to pass in modpost. 140# Otherwise, allmodconfig would fail with "Argument list too long". 141quiet_cmd_modpost = MODPOST $@ 142 cmd_modpost = sed 's/\.ko$$/$(prelink-ext)\.o/' $< | $(MODPOST) -T - 143 144$(output-symdump): $(MODORDER) $(input-symdump) $(modules:.ko=$(prelink-ext).o) FORCE 145 $(call if_changed,modpost) 146 147targets += $(output-symdump) 148 149__modpost: $(output-symdump) 150ifneq ($(KBUILD_MODPOST_NOFINAL),1) 151 $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal 152endif 153 154PHONY += FORCE 155FORCE: 156 157existing-targets := $(wildcard $(sort $(targets))) 158 159-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 160 161endif 162 163.PHONY: $(PHONY) 164