LXR linux/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# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
  36# This is solely useful to speed up test compiles
  37
  38PHONY := __modpost
  39__modpost:
  40
  41include include/config/auto.conf
  42include $(srctree)/scripts/Kbuild.include
  43
  44# for mod-prelink-ext
  45include $(srctree)/scripts/Makefile.lib
  46
  47MODPOST = scripts/mod/modpost                                                           \
  48        $(if $(CONFIG_MODVERSIONS),-m)                                                  \
  49        $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a)                                        \
  50        $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E)                                  \
  51        -o $@
  52
  53ifdef MODPOST_VMLINUX
  54
  55quiet_cmd_modpost = MODPOST $@
  56      cmd_modpost = $(MODPOST) $<
  57
  58vmlinux.symvers: vmlinux.o
  59        $(call cmd,modpost)
  60
  61__modpost: vmlinux.symvers
  62
  63else
  64
  65ifeq ($(KBUILD_EXTMOD),)
  66
  67input-symdump := vmlinux.symvers
  68output-symdump := modules-only.symvers
  69
  70quiet_cmd_cat = GEN     $@
  71      cmd_cat = cat $(real-prereqs) > $@
  72
  73ifneq ($(wildcard vmlinux.symvers),)
  74
  75__modpost: Module.symvers
  76Module.symvers: vmlinux.symvers modules-only.symvers FORCE
  77        $(call if_changed,cat)
  78
  79targets += Module.symvers
  80
  81endif
  82
  83else
  84
  85# set src + obj - they may be used in the modules's Makefile
  86obj := $(KBUILD_EXTMOD)
  87src := $(obj)
  88
  89# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
  90include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
  91             $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
  92
  93# modpost option for external modules
  94MODPOST += -e
  95
  96input-symdump := Module.symvers $(KBUILD_EXTRA_SYMBOLS)
  97output-symdump := $(KBUILD_EXTMOD)/Module.symvers
  98
  99endif
 100
 101existing-input-symdump := $(wildcard $(input-symdump))
 102
 103# modpost options for modules (both in-kernel and external)
 104MODPOST += \
 105        $(addprefix -i ,$(existing-input-symdump)) \
 106        $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \
 107        $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N)
 108
 109# 'make -i -k' ignores compile errors, and builds as many modules as possible.
 110ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
 111MODPOST += -n
 112endif
 113
 114# Clear VPATH to not search for *.symvers in $(srctree). Check only $(objtree).
 115VPATH :=
 116$(input-symdump):
 117        @echo >&2 'WARNING: Symbol version dump "$@" is missing.'
 118        @echo >&2 '         Modules may not have dependencies or modversions.'
 119        @echo >&2 '         You may get many unresolved symbol warnings.'
 120
 121modules := $(sort $(shell cat $(MODORDER)))
 122
 123# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined symbols
 124ifneq ($(KBUILD_MODPOST_WARN)$(filter-out $(existing-input-symdump), $(input-symdump)),)
 125MODPOST += -w
 126endif
 127
 128# Read out modules.order to pass in modpost.
 129# Otherwise, allmodconfig would fail with "Argument list too long".
 130quiet_cmd_modpost = MODPOST $@
 131      cmd_modpost = sed 's/\.ko$$/$(mod-prelink-ext)\.o/' $< | $(MODPOST) -T -
 132
 133$(output-symdump): $(MODORDER) $(input-symdump) $(modules:.ko=$(mod-prelink-ext).o) FORCE
 134        $(call if_changed,modpost)
 135
 136targets += $(output-symdump)
 137
 138__modpost: $(output-symdump)
 139ifneq ($(KBUILD_MODPOST_NOFINAL),1)
 140        $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
 141endif
 142
 143PHONY += FORCE
 144FORCE:
 145
 146existing-targets := $(wildcard $(sort $(targets)))
 147
 148-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
 149
 150endif
 151
 152.PHONY: $(PHONY)
 153