scripts/Makefile.modpost

   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 $(MODVERDIR)/
  13 # 2) modpost is then used to
  14 # 3)  create one <module>.mod.c file pr. module
  15 # 4)  create one Module.symvers file with CRC for all exported symbols
  16 # 4a) [CONFIG_MARKERS] create one Module.markers file listing defined markers
  17 # 5) compile all <module>.mod.c files
  18 # 6) final link of the module to a <module.ko> file
  19
  20 # Step 3 is used to place certain information in the module's ELF
  21 # section, including information such as:
  22 #   Version magic (see include/vermagic.h for full details)
  23 #     - Kernel release
  24 #     - SMP is CONFIG_SMP
  25 #     - PREEMPT is CONFIG_PREEMPT
  26 #     - GCC Version
  27 #   Module info
  28 #     - Module version (MODULE_VERSION)
  29 #     - Module alias'es (MODULE_ALIAS)
  30 #     - Module license (MODULE_LICENSE)
  31 #     - See include/linux/module.h for more details
  32
  33 # Step 4 is solely used to allow module versioning in external modules,
  34 # where the CRC of each module is retrieved from the Module.symers file.
  35
  36 # KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined
  37 # symbols in the final module linking stage
  38 # KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
  39 # This is solely usefull to speed up test compiles
  40 PHONY := _modpost
  41 _modpost: __modpost
  42
  43 include include/config/auto.conf
  44 include scripts/Kbuild.include
  45
  46 ifneq ($(KBUILD_EXTMOD),)
  47 # Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
  48 include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
  49              $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
  50 endif
  51
  52 include scripts/Makefile.lib
  53
  54 kernelsymfile := $(objtree)/Module.symvers
  55 modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
  56 kernelmarkersfile := $(objtree)/Module.markers
  57 modulemarkersfile := $(firstword $(KBUILD_EXTMOD))/Module.markers
  58
  59 markersfile = $(if $(KBUILD_EXTMOD),$(modulemarkersfile),$(kernelmarkersfile))
  60
  61 # Step 1), find all modules listed in $(MODVERDIR)/
  62 __modules := $(sort $(shell grep -h '\.ko' /dev/null $(wildcard $(MODVERDIR)/*.mod)))
  63 modules   := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o)))
  64
  65 # Stop after building .o files if NOFINAL is set. Makes compile tests quicker
  66 _modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules))
  67
  68 ifneq ($(KBUILD_BUILDHOST),$(ARCH))
  69         cross_build := 1
  70 endif
  71
  72 # Step 2), invoke modpost
  73 #  Includes step 3,4
  74 modpost = scripts/mod/modpost                    \
  75  $(if $(CONFIG_MODVERSIONS),-m)                  \
  76  $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,)       \
  77  $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile)   \
  78  $(if $(KBUILD_EXTMOD),-I $(modulesymfile))      \
  79  $(if $(KBUILD_EXTRA_SYMBOLS), $(patsubst %, -e %,$(EXTRA_SYMBOLS))) \
  80  $(if $(KBUILD_EXTMOD),-o $(modulesymfile))      \
  81  $(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S)      \
  82  $(if $(CONFIG_MARKERS),-K $(kernelmarkersfile)) \
  83  $(if $(CONFIG_MARKERS),-M $(markersfile))       \
  84  $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w) \
  85  $(if $(cross_build),-c)
  86
  87 quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules
  88       cmd_modpost = $(modpost) -s
  89
  90 PHONY += __modpost
  91 __modpost: $(modules:.ko=.o) FORCE
  92         $(call cmd,modpost) $(wildcard vmlinux) $(filter-out FORCE,$^)
  93
  94 quiet_cmd_kernel-mod = MODPOST $@
  95       cmd_kernel-mod = $(modpost) $@
  96
  97 vmlinux.o: FORCE
  98         $(call cmd,kernel-mod)
  99
 100 # Declare generated files as targets for modpost
 101 $(symverfile):         __modpost ;
 102 $(modules:.ko=.mod.c): __modpost ;
 103
 104 ifdef CONFIG_MARKERS
 105 $(markersfile):        __modpost ;
 106 endif
 107
 108
 109 # Step 5), compile all *.mod.c files
 110
 111 # modname is set to make c_flags define KBUILD_MODNAME
 112 modname = $(notdir $(@:.mod.o=))
 113
 114 quiet_cmd_cc_o_c = CC      $@
 115       cmd_cc_o_c = $(CC) $(c_flags) $(CFLAGS_MODULE)    \
 116                    -c -o $@ $<
 117
 118 $(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE
 119         $(call if_changed_dep,cc_o_c)
 120
 121 targets += $(modules:.ko=.mod.o)
 122
 123 # Step 6), final link of the modules
 124 quiet_cmd_ld_ko_o = LD [M]  $@
 125       cmd_ld_ko_o = $(LD) -r $(LDFLAGS) $(LDFLAGS_MODULE) -o $@         \
 126                           $(filter-out FORCE,$^)
 127
 128 $(modules): %.ko :%.o %.mod.o FORCE
 129         $(call if_changed,ld_ko_o)
 130
 131 targets += $(modules)
 132
 133
 134 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
 135 # ---------------------------------------------------------------------------
 136
 137 PHONY += FORCE
 138
 139 FORCE:
 140
 141 # Read all saved command lines and dependencies for the $(targets) we
 142 # may be building above, using $(if_changed{,_dep}). As an
 143 # optimization, we don't need to read them if the target does not
 144 # exist, we will rebuild anyway in that case.
 145
 146 targets := $(wildcard $(sort $(targets)))
 147 cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
 148
 149 ifneq ($(cmd_files),)
 150   include $(cmd_files)
 151 endif
 152
 153
 154 # Declare the contents of the .PHONY variable as phony.  We keep that
 155 # information in a variable se we can use it in if_changed and friends.
 156
 157 .PHONY: $(PHONY)