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 in $(MODVERDIR)/, listing the name of the 10# the preliminary <module>.o file, plus all .o files 11 12# Stage 2 is handled by this file and does the following 13# 1) Find all modules from the files listed in $(MODVERDIR)/ 14# 2) modpost is then used to 15# 3) create one <module>.mod.c file pr. module 16# 4) create one Module.symvers file with CRC for all exported symbols 17# 5) compile all <module>.mod.c files 18# 6) final link of the module to a <module.ko> file 19 20# Step 3 is used to place certain information in the module's ELF 21# section, including information such as: 22# Version magic (see include/linux/vermagic.h for full details) 23# - Kernel release 24# - SMP is CONFIG_SMP 25# - PREEMPT is CONFIG_PREEMPT 26# - GCC Version 27# Module info 28# - Module version (MODULE_VERSION) 29# - Module alias'es (MODULE_ALIAS) 30# - Module license (MODULE_LICENSE) 31# - See include/linux/module.h for more details 32 33# Step 4 is solely used to allow module versioning in external modules, 34# where the CRC of each module is retrieved from the Module.symvers file. 35 36# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined 37# symbols in the final module linking stage 38# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules. 39# This is solely useful to speed up test compiles 40PHONY := _modpost 41_modpost: __modpost 42 43include include/config/auto.conf 44include scripts/Kbuild.include 45 46# When building external modules load the Kbuild file to retrieve EXTRA_SYMBOLS info 47ifneq ($(KBUILD_EXTMOD),) 48 49# set src + obj - they may be used when building the .mod.c file 50obj := $(KBUILD_EXTMOD) 51src := $(obj) 52 53# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS 54include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \ 55 $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile) 56endif 57 58include scripts/Makefile.lib 59 60kernelsymfile := $(objtree)/Module.symvers 61modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers 62 63# Step 1), find all modules listed in $(MODVERDIR)/ 64MODLISTCMD := find $(MODVERDIR) -name '*.mod' | xargs -r grep -h '\.ko$$' | sort -u 65__modules := $(shell $(MODLISTCMD)) 66modules := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o))) 67 68# Stop after building .o files if NOFINAL is set. Makes compile tests quicker 69_modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules)) 70 71# Step 2), invoke modpost 72# Includes step 3,4 73modpost = scripts/mod/modpost \ 74 $(if $(CONFIG_MODVERSIONS),-m) \ 75 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,) \ 76 $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \ 77 $(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \ 78 $(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS))) \ 79 $(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \ 80 $(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S) \ 81 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \ 82 $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w) 83 84MODPOST_OPT=$(subst -i,-n,$(filter -i,$(MAKEFLAGS))) 85 86# If CONFIG_LTO_CLANG is enabled, .o files are either LLVM IR, or empty, so we 87# need to link them into actual objects before passing them to modpost 88modpost-ext = $(if $(CONFIG_LTO_CLANG),.lto,) 89 90ifdef CONFIG_LTO_CLANG 91quiet_cmd_cc_lto_link_modules = LD [M] $@ 92cmd_cc_lto_link_modules = \ 93 $(LD) $(ld_flags) -r -o $(@) \ 94 $(shell [ -s $(@:$(modpost-ext).o=.o.symversions) ] && \ 95 echo -T $(@:$(modpost-ext).o=.o.symversions)) \ 96 --whole-archive $(filter-out FORCE,$^) 97 98$(modules:.ko=$(modpost-ext).o): %$(modpost-ext).o: %.o FORCE 99 $(call if_changed,cc_lto_link_modules) 100endif 101 102# We can go over command line length here, so be careful. 103quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules 104 cmd_modpost = $(MODLISTCMD) | sed 's/\.ko$$/$(modpost-ext)\.o/' | $(modpost) $(MODPOST_OPT) -s -T - 105 106PHONY += __modpost 107__modpost: $(modules:.ko=$(modpost-ext).o) FORCE 108 $(call cmd,modpost) $(wildcard vmlinux) 109 110quiet_cmd_kernel-mod = MODPOST $@ 111 cmd_kernel-mod = $(modpost) $@ 112 113vmlinux.o: FORCE 114 $(call cmd,kernel-mod) 115 116# Declare generated files as targets for modpost 117$(modules:.ko=$(modpost-ext).mod.c): __modpost ; 118 119# Step 5), compile all *.mod.c files 120 121# modname is set to make c_flags define KBUILD_MODNAME 122modname = $(notdir $(@:.mod.o=)) 123 124quiet_cmd_cc_o_c = CC $@ 125 cmd_cc_o_c = $(CC) $(c_flags) $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE) \ 126 -c -o $@ $< 127 128$(modules:.ko=.mod.o): %.mod.o: %$(modpost-ext).mod.c FORCE 129 $(call if_changed_dep,cc_o_c) 130 131targets += $(modules:.ko=$(modpost-ext).mod.o) 132 133ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink) 134 135# Step 6), final link of the modules with optional arch pass after final link 136quiet_cmd_ld_ko_o = LD [M] $@ 137 138ifdef CONFIG_LTO_CLANG 139 cmd_ld_ko_o = \ 140 $(LD) -r $(LDFLAGS) \ 141 $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \ 142 $(shell [ -s $(@:.ko=.o.symversions) ] && \ 143 echo -T $(@:.ko=.o.symversions)) \ 144 -o $@ --whole-archive \ 145 $(filter-out FORCE,$(^:$(modpost-ext).o=.o)) 146 147 ifdef CONFIG_FTRACE_MCOUNT_RECORD 148 cmd_ld_ko_o += ; $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) $@ 149 endif 150else 151 cmd_ld_ko_o = \ 152 $(LD) -r $(LDFLAGS) \ 153 $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \ 154 -o $@ $(filter-out FORCE,$^) ; \ 155 $(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true) 156endif 157 158$(modules): %.ko: %$(modpost-ext).o %.mod.o FORCE 159 +$(call if_changed,ld_ko_o) 160 161targets += $(modules) 162 163 164# Add FORCE to the prequisites of a target to force it to be always rebuilt. 165# --------------------------------------------------------------------------- 166 167PHONY += FORCE 168 169FORCE: 170 171# Read all saved command lines and dependencies for the $(targets) we 172# may be building above, using $(if_changed{,_dep}). As an 173# optimization, we don't need to read them if the target does not 174# exist, we will rebuild anyway in that case. 175 176targets := $(wildcard $(sort $(targets))) 177cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd)) 178 179ifneq ($(cmd_files),) 180 include $(cmd_files) 181endif 182 183 184# Declare the contents of the .PHONY variable as phony. We keep that 185# information in a variable se we can use it in if_changed and friends. 186 187.PHONY: $(PHONY) 188