LXR linux/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 $(MODVERDIR)/
  13# 2) modpost is then used to
  14# 3)  create one <module>.mod.c file pr. module
  15# 4)  create one Module.symvers file with CRC for all exported symbols
  16# 4a) [CONFIG_MARKERS] create one Module.markers file listing defined markers
  17# 5) compile all <module>.mod.c files
  18# 6) final link of the module to a <module.ko> file
  19
  20# Step 3 is used to place certain information in the module's ELF
  21# section, including information such as:
  22#   Version magic (see include/vermagic.h for full details)
  23#     - Kernel release
  24#     - SMP is CONFIG_SMP
  25#     - PREEMPT is CONFIG_PREEMPT
  26#     - GCC Version
  27#   Module info
  28#     - Module version (MODULE_VERSION)
  29#     - Module alias'es (MODULE_ALIAS)
  30#     - Module license (MODULE_LICENSE)
  31#     - See include/linux/module.h for more details
  32
  33# Step 4 is solely used to allow module versioning in external modules,
  34# where the CRC of each module is retrieved from the Module.symers file.
  35
  36# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined
  37# symbols in the final module linking stage
  38# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
  39# This is solely usefull to speed up test compiles
  40PHONY := _modpost
  41_modpost: __modpost
  42
  43include include/config/auto.conf
  44include scripts/Kbuild.include
  45
  46# When building external modules load the Kbuild file to retreive EXTRA_SYMBOLS info
  47ifneq ($(KBUILD_EXTMOD),)
  48
  49# set src + obj - they may be used when building the .mod.c file
  50obj := $(KBUILD_EXTMOD)
  51src := $(obj)
  52
  53# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
  54include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
  55             $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
  56endif
  57
  58include scripts/Makefile.lib
  59
  60kernelsymfile := $(objtree)/Module.symvers
  61modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
  62kernelmarkersfile := $(objtree)/Module.markers
  63modulemarkersfile := $(firstword $(KBUILD_EXTMOD))/Module.markers
  64
  65markersfile = $(if $(KBUILD_EXTMOD),$(modulemarkersfile),$(kernelmarkersfile))
  66
  67# Step 1), find all modules listed in $(MODVERDIR)/
  68__modules := $(sort $(shell grep -h '\.ko' /dev/null $(wildcard $(MODVERDIR)/*.mod)))
  69modules   := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o)))
  70
  71# Stop after building .o files if NOFINAL is set. Makes compile tests quicker
  72_modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules))
  73
  74ifneq ($(KBUILD_BUILDHOST),$(ARCH))
  75        cross_build := 1
  76endif
  77
  78# Step 2), invoke modpost
  79#  Includes step 3,4
  80modpost = scripts/mod/modpost                    \
  81 $(if $(CONFIG_MODVERSIONS),-m)                  \
  82 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,)       \
  83 $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile)   \
  84 $(if $(KBUILD_EXTMOD),-I $(modulesymfile))      \
  85 $(if $(KBUILD_EXTRA_SYMBOLS), $(patsubst %, -e %,$(EXTRA_SYMBOLS))) \
  86 $(if $(KBUILD_EXTMOD),-o $(modulesymfile))      \
  87 $(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S)      \
  88 $(if $(CONFIG_MARKERS),-K $(kernelmarkersfile)) \
  89 $(if $(CONFIG_MARKERS),-M $(markersfile))       \
  90 $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w) \
  91 $(if $(cross_build),-c)
  92
  93quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules
  94      cmd_modpost = $(modpost) -s
  95
  96PHONY += __modpost
  97__modpost: $(modules:.ko=.o) FORCE
  98        $(call cmd,modpost) $(wildcard vmlinux) $(filter-out FORCE,$^)
  99
 100quiet_cmd_kernel-mod = MODPOST $@
 101      cmd_kernel-mod = $(modpost) $@
 102
 103vmlinux.o: FORCE
 104        @rm -fr $(kernelmarkersfile)
 105        $(call cmd,kernel-mod)
 106
 107# Declare generated files as targets for modpost
 108$(symverfile):         __modpost ;
 109$(modules:.ko=.mod.c): __modpost ;
 110
 111ifdef CONFIG_MARKERS
 112$(markersfile):        __modpost ;
 113endif
 114
 115
 116# Step 5), compile all *.mod.c files
 117
 118# modname is set to make c_flags define KBUILD_MODNAME
 119modname = $(notdir $(@:.mod.o=))
 120
 121quiet_cmd_cc_o_c = CC      $@
 122      cmd_cc_o_c = $(CC) $(c_flags) $(CFLAGS_MODULE)    \
 123                   -c -o $@ $<
 124
 125$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE
 126        $(call if_changed_dep,cc_o_c)
 127
 128targets += $(modules:.ko=.mod.o)
 129
 130# Step 6), final link of the modules
 131quiet_cmd_ld_ko_o = LD [M]  $@
 132      cmd_ld_ko_o = $(LD) -r $(LDFLAGS) $(LDFLAGS_MODULE) -o $@         \
 133                          $(filter-out FORCE,$^)
 134
 135$(modules): %.ko :%.o %.mod.o FORCE
 136        $(call if_changed,ld_ko_o)
 137
 138targets += $(modules)
 139
 140
 141# Add FORCE to the prequisites of a target to force it to be always rebuilt.
 142# ---------------------------------------------------------------------------
 143
 144PHONY += FORCE
 145
 146FORCE:
 147
 148# Read all saved command lines and dependencies for the $(targets) we
 149# may be building above, using $(if_changed{,_dep}). As an
 150# optimization, we don't need to read them if the target does not
 151# exist, we will rebuild anyway in that case.
 152
 153targets := $(wildcard $(sort $(targets)))
 154cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
 155
 156ifneq ($(cmd_files),)
 157  include $(cmd_files)
 158endif
 159
 160
 161# Declare the contents of the .PHONY variable as phony.  We keep that
 162# information in a variable se we can use it in if_changed and friends.
 163
 164.PHONY: $(PHONY)
 165