scripts/Makefile.modpost

   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, listing the name of the preliminary <module>.o file,
  10 #    plus all .o files
  11 # d) modules.order, which lists all the modules
  12
  13 # Stage 2 is handled by this file and does the following
  14 # 1) Find all modules listed in modules.order
  15 # 2) modpost is then used to
  16 # 3)  create one <module>.mod.c file pr. module
  17 # 4)  create one Module.symvers file with CRC for all exported symbols
  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/linux/vermagic.h for full details)
  22 #     - Kernel release
  23 #     - SMP is CONFIG_SMP
  24 #     - PREEMPT is CONFIG_PREEMPT[_RT]
  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 retrieved from the Module.symvers file.
  34
  35 # KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined
  36 # symbols in the final module linking stage
  37 # KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
  38 # This is solely useful to speed up test compiles
  39
  40 PHONY := __modpost
  41 __modpost:
  42
  43 include include/config/auto.conf
  44 include scripts/Kbuild.include
  45
  46 MODPOST = scripts/mod/modpost                                                           \
  47         $(if $(CONFIG_MODVERSIONS),-m)                                                  \
  48         $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a)                                        \
  49         $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E)                                  \
  50         $(if $(KBUILD_MODPOST_WARN),-w) \
  51         -o $@
  52
  53 ifdef MODPOST_VMLINUX
  54
  55 quiet_cmd_modpost = MODPOST $@
  56       cmd_modpost = $(MODPOST) $<
  57
  58 vmlinux.symvers: vmlinux.o
  59         $(call cmd,modpost)
  60
  61 __modpost: vmlinux.symvers
  62
  63 else
  64
  65 ifeq ($(KBUILD_EXTMOD),)
  66
  67 input-symdump := vmlinux.symvers
  68 output-symdump := modules-only.symvers
  69
  70 quiet_cmd_cat = GEN     $@
  71       cmd_cat = cat $(real-prereqs) > $@
  72
  73 ifneq ($(wildcard vmlinux.symvers),)
  74
  75 __modpost: Module.symvers
  76 Module.symvers: vmlinux.symvers modules-only.symvers FORCE
  77         $(call if_changed,cat)
  78
  79 targets += Module.symvers
  80
  81 endif
  82
  83 else
  84
  85 # set src + obj - they may be used in the modules's Makefile
  86 obj := $(KBUILD_EXTMOD)
  87 src := $(obj)
  88
  89 # Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
  90 include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
  91              $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
  92
  93 # modpost option for external modules
  94 MODPOST += -e
  95
  96 input-symdump := Module.symvers $(KBUILD_EXTRA_SYMBOLS)
  97 output-symdump := $(KBUILD_EXTMOD)/Module.symvers
  98
  99 endif
 100
 101 # modpost options for modules (both in-kernel and external)
 102 MODPOST += \
 103         $(addprefix -i ,$(wildcard $(input-symdump))) \
 104         $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \
 105         $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N)
 106
 107 # 'make -i -k' ignores compile errors, and builds as many modules as possible.
 108 ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
 109 MODPOST += -n
 110 endif
 111
 112 # Clear VPATH to not search for *.symvers in $(srctree). Check only $(objtree).
 113 VPATH :=
 114 $(input-symdump):
 115         @echo >&2 'WARNING: Symbol version dump "$@" is missing.'
 116         @echo >&2 '         Modules may not have dependencies or modversions.'
 117
 118 # Read out modules.order to pass in modpost.
 119 # Otherwise, allmodconfig would fail with "Argument list too long".
 120 quiet_cmd_modpost = MODPOST $@
 121       cmd_modpost = sed 's/ko$$/o/' $< | $(MODPOST) -T -
 122
 123 $(output-symdump): $(MODORDER) $(input-symdump) FORCE
 124         $(call if_changed,modpost)
 125
 126 targets += $(output-symdump)
 127
 128 __modpost: $(output-symdump)
 129 ifneq ($(KBUILD_MODPOST_NOFINAL),1)
 130         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
 131 endif
 132
 133 PHONY += FORCE
 134 FORCE:
 135
 136 existing-targets := $(wildcard $(sort $(targets)))
 137
 138 -include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
 139
 140 endif
 141
 142 .PHONY: $(PHONY)