Back to home page

LXR

 
 

    


0001 # ===========================================================================
0002 # Module versions
0003 # ===========================================================================
0004 #
0005 # Stage one of module building created the following:
0006 # a) The individual .o files used for the module
0007 # b) A <module>.o file which is the .o files above linked together
0008 # c) A <module>.mod file in $(MODVERDIR)/, listing the name of the
0009 #    the preliminary <module>.o file, plus all .o files
0010 
0011 # Stage 2 is handled by this file and does the following
0012 # 1) Find all modules from the files listed in $(MODVERDIR)/
0013 # 2) modpost is then used to
0014 # 3)  create one <module>.mod.c file pr. module
0015 # 4)  create one Module.symvers file with CRC for all exported symbols
0016 # 5) compile all <module>.mod.c files
0017 # 6) final link of the module to a <module.ko> file
0018 
0019 # Step 3 is used to place certain information in the module's ELF
0020 # section, including information such as:
0021 #   Version magic (see include/linux/vermagic.h for full details)
0022 #     - Kernel release
0023 #     - SMP is CONFIG_SMP
0024 #     - PREEMPT is CONFIG_PREEMPT
0025 #     - GCC Version
0026 #   Module info
0027 #     - Module version (MODULE_VERSION)
0028 #     - Module alias'es (MODULE_ALIAS)
0029 #     - Module license (MODULE_LICENSE)
0030 #     - See include/linux/module.h for more details
0031 
0032 # Step 4 is solely used to allow module versioning in external modules,
0033 # where the CRC of each module is retrieved from the Module.symvers file.
0034 
0035 # KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined
0036 # symbols in the final module linking stage
0037 # KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
0038 # This is solely useful to speed up test compiles
0039 PHONY := _modpost
0040 _modpost: __modpost
0041 
0042 include include/config/auto.conf
0043 include scripts/Kbuild.include
0044 
0045 # When building external modules load the Kbuild file to retrieve EXTRA_SYMBOLS info
0046 ifneq ($(KBUILD_EXTMOD),)
0047 
0048 # set src + obj - they may be used when building the .mod.c file
0049 obj := $(KBUILD_EXTMOD)
0050 src := $(obj)
0051 
0052 # Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
0053 include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \ 
0054              $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
0055 endif
0056 
0057 include scripts/Makefile.lib
0058 
0059 kernelsymfile := $(objtree)/Module.symvers
0060 modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
0061 
0062 # Step 1), find all modules listed in $(MODVERDIR)/
0063 MODLISTCMD := find $(MODVERDIR) -name '*.mod' | xargs -r grep -h '\.ko$$' | sort -u
0064 __modules := $(shell $(MODLISTCMD))
0065 modules   := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o)))
0066 
0067 # Stop after building .o files if NOFINAL is set. Makes compile tests quicker
0068 _modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules))
0069 
0070 # Step 2), invoke modpost
0071 #  Includes step 3,4
0072 modpost = scripts/mod/modpost                    \
0073  $(if $(CONFIG_MODVERSIONS),-m)                  \
0074  $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,)       \
0075  $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile)   \
0076  $(if $(KBUILD_EXTMOD),-I $(modulesymfile))      \
0077  $(if $(KBUILD_EXTRA_SYMBOLS), $(patsubst %, -e %,$(KBUILD_EXTRA_SYMBOLS))) \
0078  $(if $(KBUILD_EXTMOD),-o $(modulesymfile))      \
0079  $(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S)      \
0080  $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E)  \
0081  $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w)
0082 
0083 MODPOST_OPT=$(subst -i,-n,$(filter -i,$(MAKEFLAGS)))
0084 
0085 # We can go over command line length here, so be careful.
0086 quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules
0087       cmd_modpost = $(MODLISTCMD) | sed 's/\.ko$$/.o/' | $(modpost) $(MODPOST_OPT) -s -T -
0088 
0089 PHONY += __modpost
0090 __modpost: $(modules:.ko=.o) FORCE
0091         $(call cmd,modpost) $(wildcard vmlinux)
0092 
0093 quiet_cmd_kernel-mod = MODPOST $@
0094       cmd_kernel-mod = $(modpost) $@
0095 
0096 vmlinux.o: FORCE
0097         $(call cmd,kernel-mod)
0098 
0099 # Declare generated files as targets for modpost
0100 $(symverfile):         __modpost ;
0101 $(modules:.ko=.mod.c): __modpost ;
0102 
0103 
0104 # Step 5), compile all *.mod.c files
0105 
0106 # modname is set to make c_flags define KBUILD_MODNAME
0107 modname = $(notdir $(@:.mod.o=))
0108 
0109 quiet_cmd_cc_o_c = CC      $@
0110       cmd_cc_o_c = $(CC) $(c_flags) $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE) \
0111                    -c -o $@ $<
0112 
0113 $(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE
0114         $(call if_changed_dep,cc_o_c)
0115 
0116 targets += $(modules:.ko=.mod.o)
0117 
0118 ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
0119 
0120 # Step 6), final link of the modules with optional arch pass after final link
0121 quiet_cmd_ld_ko_o = LD [M]  $@
0122       cmd_ld_ko_o =                                                     \
0123         $(LD) -r $(LDFLAGS)                                             \
0124                  $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE)             \
0125                  -o $@ $(filter-out FORCE,$^) ;                         \
0126         $(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
0127 
0128 $(modules): %.ko :%.o %.mod.o FORCE
0129         +$(call if_changed,ld_ko_o)
0130 
0131 targets += $(modules)
0132 
0133 
0134 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
0135 # ---------------------------------------------------------------------------
0136 
0137 PHONY += FORCE
0138 
0139 FORCE:
0140 
0141 # Read all saved command lines and dependencies for the $(targets) we
0142 # may be building above, using $(if_changed{,_dep}). As an
0143 # optimization, we don't need to read them if the target does not
0144 # exist, we will rebuild anyway in that case.
0145 
0146 targets := $(wildcard $(sort $(targets)))
0147 cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
0148 
0149 ifneq ($(cmd_files),)
0150   include $(cmd_files)
0151 endif
0152 
0153 
0154 # Declare the contents of the .PHONY variable as phony.  We keep that
0155 # information in a variable se we can use it in if_changed and friends.
0156 
0157 .PHONY: $(PHONY)