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 per 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 PHONY := __modpost
  36 __modpost:
  37
  38 include include/config/auto.conf
  39 include $(srctree)/scripts/Kbuild.include
  40
  41 MODPOST = scripts/mod/modpost
  42
  43 modpost-args =                                                                          \
  44         $(if $(CONFIG_MODULES),-M)                                                      \
  45         $(if $(CONFIG_MODVERSIONS),-m)                                                  \
  46         $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a)                                        \
  47         $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E)                                  \
  48         $(if $(KBUILD_MODPOST_WARN),-w)                                                 \
  49         $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS))                                     \
  50         $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N)       \
  51         $(if $(findstring 1, $(KBUILD_EXTRA_WARN)),-W)                                  \
  52         -o $@
  53
  54 modpost-deps := $(MODPOST)
  55
  56 # 'make -i -k' ignores compile errors, and builds as many modules as possible.
  57 ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
  58 modpost-args += -n
  59 endif
  60
  61 # Read out modules.order to pass in modpost.
  62 # Otherwise, allmodconfig would fail with "Argument list too long".
  63 ifdef KBUILD_MODULES
  64 modpost-args += -T $(MODORDER)
  65 modpost-deps += $(MODORDER)
  66 endif
  67
  68 ifeq ($(KBUILD_EXTMOD),)
  69
  70 # Generate the list of in-tree objects in vmlinux
  71 # ---------------------------------------------------------------------------
  72
  73 # This is used to retrieve symbol versions generated by genksyms.
  74 ifdef CONFIG_MODVERSIONS
  75 vmlinux.symvers Module.symvers: .vmlinux.objs
  76 endif
  77
  78 # Ignore libgcc.a
  79 # Some architectures do '$(CC) --print-libgcc-file-name' to borrow libgcc.a
  80 # from the toolchain, but there is no EXPORT_SYMBOL in it.
  81
  82 quiet_cmd_vmlinux_objs = GEN     $@
  83       cmd_vmlinux_objs =                \
  84         for f in $(real-prereqs); do    \
  85                 case $${f} in           \
  86                 *libgcc.a) ;;           \
  87                 *) $(AR) t $${f} ;;     \
  88                 esac                    \
  89         done > $@
  90
  91 targets += .vmlinux.objs
  92 .vmlinux.objs: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
  93         $(call if_changed,vmlinux_objs)
  94
  95 ifdef CONFIG_TRIM_UNUSED_KSYMS
  96 ksym-wl := $(CONFIG_UNUSED_KSYMS_WHITELIST)
  97 ksym-wl := $(if $(filter-out /%, $(ksym-wl)),$(srctree)/)$(ksym-wl)
  98 modpost-args += -t $(addprefix -u , $(ksym-wl))
  99 modpost-deps += $(ksym-wl)
 100 endif
 101
 102 ifeq ($(wildcard vmlinux.o),)
 103 missing-input := vmlinux.o
 104 output-symdump := modules-only.symvers
 105 else
 106 modpost-args += vmlinux.o
 107 modpost-deps += vmlinux.o
 108 output-symdump := $(if $(KBUILD_MODULES), Module.symvers, vmlinux.symvers)
 109 endif
 110
 111 else
 112
 113 # set src + obj - they may be used in the modules's Makefile
 114 obj := $(KBUILD_EXTMOD)
 115 src := $(obj)
 116
 117 # Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
 118 include $(kbuild-file)
 119
 120 output-symdump := $(KBUILD_EXTMOD)/Module.symvers
 121
 122 ifeq ($(wildcard Module.symvers),)
 123 missing-input := Module.symvers
 124 else
 125 modpost-args += -i Module.symvers
 126 modpost-deps += Module.symvers
 127 endif
 128
 129 modpost-args += -e $(addprefix -i , $(KBUILD_EXTRA_SYMBOLS))
 130
 131 endif # ($(KBUILD_EXTMOD),)
 132
 133 quiet_cmd_modpost = MODPOST $@
 134       cmd_modpost = \
 135         $(if $(missing-input), \
 136                 echo >&2 "WARNING: $(missing-input) is missing."; \
 137                 echo >&2 "         Modules may not have dependencies or modversions."; \
 138                 echo >&2 "         You may get many unresolved symbol errors."; \
 139                 echo >&2 "         You can set KBUILD_MODPOST_WARN=1 to turn errors into warning"; \
 140                 echo >&2 "         if you want to proceed at your own risk.";) \
 141         $(MODPOST) $(modpost-args)
 142
 143 targets += $(output-symdump)
 144 $(output-symdump): $(modpost-deps) FORCE
 145         $(call if_changed,modpost)
 146
 147 __modpost: $(output-symdump)
 148 PHONY += FORCE
 149 FORCE:
 150
 151 existing-targets := $(wildcard $(sort $(targets)))
 152
 153 -include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
 154
 155 .PHONY: $(PHONY)