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# 5) compile all <module>.mod.c files 19# 6) final link of the module to a <module.ko> file 20 21# Step 3 is used to place certain information in the module's ELF 22# section, including information such as: 23# Version magic (see include/linux/vermagic.h for full details) 24# - Kernel release 25# - SMP is CONFIG_SMP 26# - PREEMPT is CONFIG_PREEMPT 27# - GCC Version 28# Module info 29# - Module version (MODULE_VERSION) 30# - Module alias'es (MODULE_ALIAS) 31# - Module license (MODULE_LICENSE) 32# - See include/linux/module.h for more details 33 34# Step 4 is solely used to allow module versioning in external modules, 35# where the CRC of each module is retrieved from the Module.symvers file. 36 37# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined 38# symbols in the final module linking stage 39# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules. 40# This is solely useful to speed up test compiles 41 42PHONY := __modpost 43__modpost: 44 45include include/config/auto.conf 46include scripts/Kbuild.include 47 48kernelsymfile := $(objtree)/Module.symvers 49modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers 50 51MODPOST = scripts/mod/modpost \ 52 $(if $(CONFIG_MODVERSIONS),-m) \ 53 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \ 54 $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \ 55 $(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \ 56 $(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS))) \ 57 $(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \ 58 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \ 59 $(if $(KBUILD_MODPOST_WARN),-w) \ 60 $(if $(filter nsdeps,$(MAKECMDGOALS)),-d) 61 62ifdef MODPOST_VMLINUX 63 64__modpost: vmlinux.o 65 66quiet_cmd_modpost = MODPOST $@ 67 cmd_modpost = $(MODPOST) $@ 68 69PHONY += vmlinux.o 70vmlinux.o: 71 $(call cmd,modpost) 72 73else 74 75# When building external modules load the Kbuild file to retrieve EXTRA_SYMBOLS info 76ifneq ($(KBUILD_EXTMOD),) 77 78# set src + obj - they may be used when building the .mod.c file 79obj := $(KBUILD_EXTMOD) 80src := $(obj) 81 82# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS 83include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \ 84 $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile) 85endif 86 87include scripts/Makefile.lib 88 89# find all modules listed in modules.order 90modules := $(sort $(shell cat $(MODORDER))) 91 92# Stop after building .o files if NOFINAL is set. Makes compile tests quicker 93__modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules)) 94 @: 95 96MODPOST += $(subst -i,-n,$(filter -i,$(MAKEFLAGS))) -s -T - $(wildcard vmlinux) 97 98# We can go over command line length here, so be careful. 99quiet_cmd_modpost = MODPOST $(words $(modules)) modules 100 cmd_modpost = sed 's/ko$$/o/' $(MODORDER) | $(MODPOST) 101 102PHONY += modules-modpost 103modules-modpost: 104 $(call cmd,modpost) 105 106# Declare generated files as targets for modpost 107$(modules:.ko=.mod.c): modules-modpost 108 109# Step 5), compile all *.mod.c files 110 111# modname is set to make c_flags define KBUILD_MODNAME 112modname = $(notdir $(@:.mod.o=)) 113 114quiet_cmd_cc_o_c = CC $@ 115 cmd_cc_o_c = $(CC) $(c_flags) $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE) \ 116 -c -o $@ $< 117 118$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE 119 $(call if_changed_dep,cc_o_c) 120 121targets += $(modules:.ko=.mod.o) 122 123ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink) 124 125# Step 6), final link of the modules with optional arch pass after final link 126quiet_cmd_ld_ko_o = LD [M] $@ 127 cmd_ld_ko_o = \ 128 $(LD) -r $(KBUILD_LDFLAGS) \ 129 $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \ 130 -o $@ $(real-prereqs) ; \ 131 $(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true) 132 133$(modules): %.ko :%.o %.mod.o FORCE 134 +$(call if_changed,ld_ko_o) 135 136targets += $(modules) 137 138nsdeps: __modpost 139 140# Add FORCE to the prequisites of a target to force it to be always rebuilt. 141# --------------------------------------------------------------------------- 142 143PHONY += FORCE 144 145FORCE: 146 147# Read all saved command lines and dependencies for the $(targets) we 148# may be building above, using $(if_changed{,_dep}). As an 149# optimization, we don't need to read them if the target does not 150# exist, we will rebuild anyway in that case. 151 152existing-targets := $(wildcard $(sort $(targets))) 153 154-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 155 156endif 157 158.PHONY: $(PHONY) 159