1# =========================================================================== 2# Module versions 3# =========================================================================== 4# 5# Stage one of module building created the following: 6# a) The individual .o files used for the module 7# b) A <module>.o file which is the .o files above linked together 8# c) A <module>.mod file in $(MODVERDIR)/, listing the name of the 9# the preliminary <module>.o file, plus all .o files 10 11# Stage 2 is handled by this file and does the following 12# 1) Find all modules from the files listed in $(MODVERDIR)/ 13# 2) modpost is then used to 14# 3) create one <module>.mod.c file pr. module 15# 4) create one Module.symvers file with CRC for all exported symbols 16# 5) compile all <module>.mod.c files 17# 6) final link of the module to a <module.ko> file 18 19# Step 3 is used to place certain information in the module's ELF 20# section, including information such as: 21# Version magic (see include/linux/vermagic.h for full details) 22# - Kernel release 23# - SMP is CONFIG_SMP 24# - PREEMPT is CONFIG_PREEMPT 25# - GCC Version 26# Module info 27# - Module version (MODULE_VERSION) 28# - Module alias'es (MODULE_ALIAS) 29# - Module license (MODULE_LICENSE) 30# - See include/linux/module.h for more details 31 32# Step 4 is solely used to allow module versioning in external modules, 33# where the CRC of each module is retrieved from the Module.symvers file. 34 35# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined 36# symbols in the final module linking stage 37# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules. 38# This is solely useful to speed up test compiles 39PHONY := _modpost 40_modpost: __modpost 41 42include include/config/auto.conf 43include scripts/Kbuild.include 44 45# When building external modules load the Kbuild file to retrieve EXTRA_SYMBOLS info 46ifneq ($(KBUILD_EXTMOD),) 47 48# set src + obj - they may be used when building the .mod.c file 49obj := $(KBUILD_EXTMOD) 50src := $(obj) 51 52# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS 53include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \ 54 $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile) 55endif 56 57include scripts/Makefile.lib 58 59kernelsymfile := $(objtree)/Module.symvers 60modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers 61 62# Step 1), find all modules listed in $(MODVERDIR)/ 63MODLISTCMD := find $(MODVERDIR) -name '*.mod' | xargs -r grep -h '\.ko$$' | sort -u 64__modules := $(shell $(MODLISTCMD)) 65modules := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o))) 66 67# Stop after building .o files if NOFINAL is set. Makes compile tests quicker 68_modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules)) 69 70# Step 2), invoke modpost 71# Includes step 3,4 72modpost = scripts/mod/modpost \ 73 $(if $(CONFIG_MODVERSIONS),-m) \ 74 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,) \ 75 $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \ 76 $(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \ 77 $(if $(KBUILD_EXTRA_SYMBOLS), $(patsubst %, -e %,$(KBUILD_EXTRA_SYMBOLS))) \ 78 $(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \ 79 $(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S) \ 80 $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w) 81 82MODPOST_OPT=$(subst -i,-n,$(filter -i,$(MAKEFLAGS))) 83 84# We can go over command line length here, so be careful. 85quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules 86 cmd_modpost = $(MODLISTCMD) | sed 's/\.ko$$/.o/' | $(modpost) $(MODPOST_OPT) -s -T - 87 88PHONY += __modpost 89__modpost: $(modules:.ko=.o) FORCE 90 $(call cmd,modpost) $(wildcard vmlinux) 91 92quiet_cmd_kernel-mod = MODPOST $@ 93 cmd_kernel-mod = $(modpost) $@ 94 95vmlinux.o: FORCE 96 $(call cmd,kernel-mod) 97 98# Declare generated files as targets for modpost 99$(symverfile): __modpost ; 100$(modules:.ko=.mod.c): __modpost ; 101 102 103# Step 5), compile all *.mod.c files 104 105# modname is set to make c_flags define KBUILD_MODNAME 106modname = $(notdir $(@:.mod.o=)) 107 108quiet_cmd_cc_o_c = CC $@ 109 cmd_cc_o_c = $(CC) $(c_flags) $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE) \ 110 -c -o $@ $< 111 112$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE 113 $(call if_changed_dep,cc_o_c) 114 115targets += $(modules:.ko=.mod.o) 116 117# Step 6), final link of the modules 118quiet_cmd_ld_ko_o = LD [M] $@ 119 cmd_ld_ko_o = $(LD) -r $(LDFLAGS) \ 120 $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \ 121 -o $@ $(filter-out FORCE,$^) 122 123$(modules): %.ko :%.o %.mod.o FORCE 124 $(call if_changed,ld_ko_o) 125 126targets += $(modules) 127 128 129# Add FORCE to the prequisites of a target to force it to be always rebuilt. 130# --------------------------------------------------------------------------- 131 132PHONY += FORCE 133 134FORCE: 135 136# Read all saved command lines and dependencies for the $(targets) we 137# may be building above, using $(if_changed{,_dep}). As an 138# optimization, we don't need to read them if the target does not 139# exist, we will rebuild anyway in that case. 140 141targets := $(wildcard $(sort $(targets))) 142cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd)) 143 144ifneq ($(cmd_files),) 145 include $(cmd_files) 146endif 147 148 149# Declare the contents of the .PHONY variable as phony. We keep that 150# information in a variable se we can use it in if_changed and friends. 151 152.PHONY: $(PHONY) 153