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 wich 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 retreived from the Module.symers file. 34 35.PHONY: _modpost 36_modpost: __modpost 37 38include .config 39include scripts/Kbuild.include 40include scripts/Makefile.lib 41 42symverfile := $(objtree)/Module.symvers 43 44# Step 1), find all modules listed in $(MODVERDIR)/ 45__modules := $(sort $(shell grep -h '\.ko' /dev/null $(wildcard $(MODVERDIR)/*.mod))) 46modules := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o))) 47 48_modpost: $(modules) 49 50 51# Step 2), invoke modpost 52# Includes step 3,4 53quiet_cmd_modpost = MODPOST 54 cmd_modpost = scripts/mod/modpost \ 55 $(if $(CONFIG_MODVERSIONS),-m) \ 56 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,) \ 57 $(if $(KBUILD_EXTMOD),-i,-o) $(symverfile) \ 58 $(filter-out FORCE,$^) 59 60.PHONY: __modpost 61__modpost: $(wildcard vmlinux) $(modules:.ko=.o) FORCE 62 $(call cmd,modpost) 63 64# Declare generated files as targets for modpost 65$(symverfile): __modpost ; 66$(modules:.ko=.mod.c): __modpost ; 67 68 69# Step 5), compile all *.mod.c files 70 71# modname is set to make c_flags define KBUILD_MODNAME 72modname = $(*F) 73 74quiet_cmd_cc_o_c = CC $@ 75 cmd_cc_o_c = $(CC) $(c_flags) $(CFLAGS_MODULE) \ 76 -c -o $@ $< 77 78$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE 79 $(call if_changed_dep,cc_o_c) 80 81targets += $(modules:.ko=.mod.o) 82 83# Step 6), final link of the modules 84quiet_cmd_ld_ko_o = LD [M] $@ 85 cmd_ld_ko_o = $(LD) $(LDFLAGS) $(LDFLAGS_MODULE) -o $@ \ 86 $(filter-out FORCE,$^) 87 88$(modules): %.ko :%.o %.mod.o FORCE 89 $(call if_changed,ld_ko_o) 90 91targets += $(modules) 92 93 94# Add FORCE to the prequisites of a target to force it to be always rebuilt. 95# --------------------------------------------------------------------------- 96 97.PHONY: FORCE 98 99FORCE: 100 101# Read all saved command lines and dependencies for the $(targets) we 102# may be building above, using $(if_changed{,_dep}). As an 103# optimization, we don't need to read them if the target does not 104# exist, we will rebuild anyway in that case. 105 106targets := $(wildcard $(sort $(targets))) 107cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd)) 108 109ifneq ($(cmd_files),) 110 include $(cmd_files) 111endif 112