Makefile.modpost 6.7 KB

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  1. # SPDX-License-Identifier: GPL-2.0
  2. # ===========================================================================
  3. # Module versions
  4. # ===========================================================================
  5. #
  6. # Stage one of module building created the following:
  7. # a) The individual .o files used for the module
  8. # b) A <module>.o file which is the .o files above linked together
  9. # c) A <module>.mod file in $(MODVERDIR)/, listing the name of the
  10. # the preliminary <module>.o file, plus all .o files
  11. # Stage 2 is handled by this file and does the following
  12. # 1) Find all modules from the files listed in $(MODVERDIR)/
  13. # 2) modpost is then used to
  14. # 3) create one <module>.mod.c file pr. module
  15. # 4) create one Module.symvers file with CRC for all exported symbols
  16. # 5) compile all <module>.mod.c files
  17. # 6) final link of the module to a <module.ko> file
  18. # Step 3 is used to place certain information in the module's ELF
  19. # section, including information such as:
  20. # Version magic (see include/linux/vermagic.h for full details)
  21. # - Kernel release
  22. # - SMP is CONFIG_SMP
  23. # - PREEMPT is CONFIG_PREEMPT
  24. # - GCC Version
  25. # Module info
  26. # - Module version (MODULE_VERSION)
  27. # - Module alias'es (MODULE_ALIAS)
  28. # - Module license (MODULE_LICENSE)
  29. # - See include/linux/module.h for more details
  30. # Step 4 is solely used to allow module versioning in external modules,
  31. # where the CRC of each module is retrieved from the Module.symvers file.
  32. # KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined
  33. # symbols in the final module linking stage
  34. # KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
  35. # This is solely useful to speed up test compiles
  36. PHONY := _modpost
  37. _modpost: __modpost
  38. include include/config/auto.conf
  39. include scripts/Kbuild.include
  40. # When building external modules load the Kbuild file to retrieve EXTRA_SYMBOLS info
  41. ifneq ($(KBUILD_EXTMOD),)
  42. # set src + obj - they may be used when building the .mod.c file
  43. obj := $(KBUILD_EXTMOD)
  44. src := $(obj)
  45. # Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
  46. include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
  47. $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
  48. endif
  49. include scripts/Makefile.lib
  50. kernelsymfile := $(objtree)/Module.symvers
  51. modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
  52. # Step 1), find all modules listed in $(MODVERDIR)/
  53. MODLISTCMD := find $(MODVERDIR) -name '*.mod' | xargs -r grep -h '\.ko$$' | sort -u
  54. __modules := $(shell $(MODLISTCMD))
  55. modules := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o)))
  56. # Stop after building .o files if NOFINAL is set. Makes compile tests quicker
  57. _modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules))
  58. # Step 2), invoke modpost
  59. # Includes step 3,4
  60. modpost = scripts/mod/modpost \
  61. $(if $(CONFIG_MODVERSIONS),-m) \
  62. $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,) \
  63. $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \
  64. $(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \
  65. $(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS))) \
  66. $(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \
  67. $(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S) \
  68. $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
  69. $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),$(if $(KBUILD_MODPOST_FAIL_ON_WARNINGS),,-w))
  70. MODPOST_OPT=$(subst -i,-n,$(filter -i,$(MAKEFLAGS)))
  71. # If CONFIG_LTO_CLANG is enabled, .o files are either LLVM IR, or empty, so we
  72. # need to link them into actual objects before passing them to modpost
  73. modpost-ext = $(if $(CONFIG_LTO_CLANG),.lto,)
  74. ifdef CONFIG_LTO_CLANG
  75. quiet_cmd_cc_lto_link_modules = LD [M] $@
  76. cmd_cc_lto_link_modules = \
  77. $(LD) $(ld_flags) -r -o $(@) \
  78. $(shell [ -s $(@:$(modpost-ext).o=.o.symversions) ] && \
  79. echo -T $(@:$(modpost-ext).o=.o.symversions)) \
  80. --whole-archive $(filter-out FORCE,$^)
  81. $(modules:.ko=$(modpost-ext).o): %$(modpost-ext).o: %.o FORCE
  82. $(call if_changed,cc_lto_link_modules)
  83. endif
  84. # We can go over command line length here, so be careful.
  85. quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules
  86. cmd_modpost = $(MODLISTCMD) | sed 's/\.ko$$/$(modpost-ext)\.o/' | $(modpost) $(MODPOST_OPT) -s -T -
  87. PHONY += __modpost
  88. __modpost: $(modules:.ko=$(modpost-ext).o) FORCE
  89. $(call cmd,modpost) $(wildcard vmlinux)
  90. quiet_cmd_kernel-mod = MODPOST $@
  91. cmd_kernel-mod = $(modpost) $@
  92. vmlinux.o: FORCE
  93. $(call cmd,kernel-mod)
  94. # Declare generated files as targets for modpost
  95. $(modules:.ko=$(modpost-ext).mod.c): __modpost ;
  96. # Step 5), compile all *.mod.c files
  97. # modname is set to make c_flags define KBUILD_MODNAME
  98. modname = $(notdir $(@:.mod.o=))
  99. quiet_cmd_cc_o_c = CC $@
  100. cmd_cc_o_c = $(CC) $(c_flags) $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE) \
  101. -c -o $@ $<
  102. $(modules:.ko=.mod.o): %.mod.o: %$(modpost-ext).mod.c FORCE
  103. $(call if_changed_dep,cc_o_c)
  104. targets += $(modules:.ko=$(modpost-ext).mod.o)
  105. ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
  106. # Step 6), final link of the modules with optional arch pass after final link
  107. quiet_cmd_ld_ko_o = LD [M] $@
  108. ifdef CONFIG_LTO_CLANG
  109. cmd_ld_ko_o = \
  110. $(LD) -r $(LDFLAGS) \
  111. $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
  112. $(shell [ -s $(@:.ko=.o.symversions) ] && \
  113. echo -T $(@:.ko=.o.symversions)) \
  114. -o $@ --whole-archive \
  115. $(filter-out FORCE,$(^:$(modpost-ext).o=.o))
  116. ifdef CONFIG_FTRACE_MCOUNT_RECORD
  117. cmd_ld_ko_o += ; $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) $@
  118. endif
  119. else
  120. cmd_ld_ko_o = \
  121. $(LD) -r $(LDFLAGS) \
  122. $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
  123. -o $@ $(filter-out FORCE,$^) ; \
  124. $(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
  125. endif
  126. $(modules): %.ko: %$(modpost-ext).o %.mod.o FORCE
  127. +$(call if_changed,ld_ko_o)
  128. targets += $(modules)
  129. # Add FORCE to the prequisites of a target to force it to be always rebuilt.
  130. # ---------------------------------------------------------------------------
  131. PHONY += FORCE
  132. FORCE:
  133. # Read all saved command lines and dependencies for the $(targets) we
  134. # may be building above, using $(if_changed{,_dep}). As an
  135. # optimization, we don't need to read them if the target does not
  136. # exist, we will rebuild anyway in that case.
  137. targets := $(wildcard $(sort $(targets)))
  138. cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
  139. ifneq ($(cmd_files),)
  140. include $(cmd_files)
  141. endif
  142. # Declare the contents of the .PHONY variable as phony. We keep that
  143. # information in a variable se we can use it in if_changed and friends.
  144. .PHONY: $(PHONY)