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/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.symers 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 usefull to speed up test compiles 39PHONY := _modpost 40_modpost: __modpost 41 42include include/config/auto.conf 43include scripts/Kbuild.include 44include scripts/Makefile.lib 45 46kernelsymfile := $(objtree)/Module.symvers 47modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers 48 49# Step 1), find all modules listed in $(MODVERDIR)/ 50__modules := $(sort $(shell grep -h '\.ko' /dev/null $(wildcard $(MODVERDIR)/*.mod))) 51modules := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o))) 52 53# Stop after building .o files if NOFINAL is set. Makes compile tests quicker 54_modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules)) 55 56 57# Step 2), invoke modpost 58# Includes step 3,4 59modpost = scripts/mod/modpost \ 60 $(if $(CONFIG_MODVERSIONS),-m) \ 61 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,) \ 62 $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \ 63 $(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \ 64 $(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \ 65 $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w) 66 67quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules 68 cmd_modpost = $(modpost) -s 69 70PHONY += __modpost 71__modpost: $(modules:.ko=.o) FORCE 72 $(call cmd,modpost) $(wildcard vmlinux) $(filter-out FORCE,$^) 73 74quiet_cmd_kernel-mod = MODPOST $@ 75 cmd_kernel-mod = $(modpost) $@ 76 77vmlinux.o: FORCE 78 $(call cmd,kernel-mod) 79 80# Declare generated files as targets for modpost 81$(symverfile): __modpost ; 82$(modules:.ko=.mod.c): __modpost ; 83 84 85# Step 5), compile all *.mod.c files 86 87# modname is set to make c_flags define KBUILD_MODNAME 88modname = $(notdir $(@:.mod.o=)) 89 90quiet_cmd_cc_o_c = CC $@ 91 cmd_cc_o_c = $(CC) $(c_flags) $(CFLAGS_MODULE) \ 92 -c -o $@ $< 93 94$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE 95 $(call if_changed_dep,cc_o_c) 96 97targets += $(modules:.ko=.mod.o) 98 99# Step 6), final link of the modules 100quiet_cmd_ld_ko_o = LD [M] $@ 101 cmd_ld_ko_o = $(LD) -r $(LDFLAGS) $(LDFLAGS_MODULE) -o $@ \ 102 $(filter-out FORCE,$^) 103 104$(modules): %.ko :%.o %.mod.o FORCE 105 $(call if_changed,ld_ko_o) 106 107targets += $(modules) 108 109 110# Add FORCE to the prequisites of a target to force it to be always rebuilt. 111# --------------------------------------------------------------------------- 112 113PHONY += FORCE 114 115FORCE: 116 117# Read all saved command lines and dependencies for the $(targets) we 118# may be building above, using $(if_changed{,_dep}). As an 119# optimization, we don't need to read them if the target does not 120# exist, we will rebuild anyway in that case. 121 122targets := $(wildcard $(sort $(targets))) 123cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd)) 124 125ifneq ($(cmd_files),) 126 include $(cmd_files) 127endif 128 129 130# Declare the contents of the .PHONY variable as phony. We keep that 131# information in a variable se we can use it in if_changed and friends. 132 133.PHONY: $(PHONY) 134