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 46kernelsymfile := $(objtree)/Module.symvers 47modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers 48 49MODPOST = scripts/mod/modpost \ 50 $(if $(CONFIG_MODVERSIONS),-m) \ 51 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \ 52 $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \ 53 $(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \ 54 $(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS))) \ 55 $(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \ 56 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \ 57 $(if $(KBUILD_MODPOST_WARN),-w) \ 58 $(if $(filter nsdeps,$(MAKECMDGOALS)),-d) 59 60ifdef MODPOST_VMLINUX 61 62quiet_cmd_modpost = MODPOST vmlinux.o 63 cmd_modpost = $(MODPOST) vmlinux.o 64 65__modpost: 66 $(call cmd,modpost) 67 68else 69 70# When building external modules load the Kbuild file to retrieve EXTRA_SYMBOLS info 71ifneq ($(KBUILD_EXTMOD),) 72 73# set src + obj - they may be used when building the .mod.c file 74obj := $(KBUILD_EXTMOD) 75src := $(obj) 76 77# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS 78include $(if $(wildcard $(src)/Kbuild), $(src)/Kbuild, $(src)/Makefile) 79endif 80 81MODPOST += $(subst -i,-n,$(filter -i,$(MAKEFLAGS))) -s -T - $(wildcard vmlinux) 82 83# find all modules listed in modules.order 84modules := $(sort $(shell cat $(MODORDER))) 85 86# With CONFIG_LTO_CLANG, .o files might be LLVM IR, so we need to link them 87# into actual objects before passing them to modpost 88modpost-ext = $(if $(CONFIG_LTO_CLANG),.lto,) 89 90ifdef CONFIG_LTO_CLANG 91quiet_cmd_cc_lto_link_modules = LTO [M] $@ 92cmd_cc_lto_link_modules = \ 93 $(LD) $(ld_flags) -r -o $(@) \ 94 $(shell [ -s $(@:$(modpost-ext).o=.o.symversions) ] && \ 95 echo -T $(@:$(modpost-ext).o=.o.symversions)) \ 96 --whole-archive $(filter-out FORCE,$^) 97 98$(modules:.ko=$(modpost-ext).o): %$(modpost-ext).o: %.o FORCE 99 $(call if_changed,cc_lto_link_modules) 100 101PHONY += FORCE 102FORCE: 103 104endif 105 106# Read out modules.order instead of expanding $(modules) to pass in modpost. 107# Otherwise, allmodconfig would fail with "Argument list too long". 108quiet_cmd_modpost = MODPOST $(words $(modules)) modules 109 cmd_modpost = sed 's/\.ko$$/$(modpost-ext)\.o/' $(MODORDER) | $(MODPOST) 110 111__modpost: $(modules:.ko=$(modpost-ext).o) 112 @$(kecho) ' Building modules, stage 2.' 113 $(call cmd,modpost) 114ifneq ($(KBUILD_MODPOST_NOFINAL),1) 115 $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal 116endif 117 118nsdeps: __modpost 119 120endif 121 122.PHONY: $(PHONY) 123