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 $(src)/Kbuild), $(src)/Kbuild, $(src)/Makefile) 94 95# modpost option for external modules 96MODPOST += -e 97 98input-symdump := Module.symvers $(KBUILD_EXTRA_SYMBOLS) 99output-symdump := $(KBUILD_EXTMOD)/Module.symvers 100 101endif 102 103# modpost options for modules (both in-kernel and external) 104MODPOST += \ 105 $(addprefix -i ,$(wildcard $(input-symdump))) \ 106 $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \ 107 $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) 108 109# 'make -i -k' ignores compile errors, and builds as many modules as possible. 110ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),) 111MODPOST += -n 112endif 113 114# Clear VPATH to not search for *.symvers in $(srctree). Check only $(objtree). 115VPATH := 116$(input-symdump): 117 @echo >&2 'WARNING: Symbol version dump "$@" is missing.' 118 @echo >&2 ' Modules may not have dependencies or modversions.' 119 120ifdef CONFIG_LTO_CLANG 121# With CONFIG_LTO_CLANG, .o files might be LLVM bitcode, so we need to run 122# LTO to compile them into native code before running modpost 123prelink-ext := .lto 124 125quiet_cmd_cc_lto_link_modules = LTO [M] $@ 126cmd_cc_lto_link_modules = \ 127 $(LD) $(ld_flags) -r -o $@ \ 128 $(shell [ -s $(@:.lto.o=.o.symversions) ] && \ 129 echo -T $(@:.lto.o=.o.symversions)) \ 130 --whole-archive $^ 131 132%.lto.o: %.o 133 $(call if_changed,cc_lto_link_modules) 134endif 135 136modules := $(sort $(shell cat $(MODORDER))) 137 138# Read out modules.order to pass in modpost. 139# Otherwise, allmodconfig would fail with "Argument list too long". 140quiet_cmd_modpost = MODPOST $@ 141 cmd_modpost = sed 's/\.ko$$/$(prelink-ext)\.o/' $< | $(MODPOST) -T - 142 143$(output-symdump): $(MODORDER) $(input-symdump) $(modules:.ko=$(prelink-ext).o) FORCE 144 $(call if_changed,modpost) 145 146targets += $(output-symdump) 147 148__modpost: $(output-symdump) 149ifneq ($(KBUILD_MODPOST_NOFINAL),1) 150 $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal 151endif 152 153PHONY += FORCE 154FORCE: 155 156existing-targets := $(wildcard $(sort $(targets))) 157 158-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 159 160endif 161 162.PHONY: $(PHONY) 163