linux/scripts/Makefile.modpost
Masahiro Yamada 5ab70ff428 kbuild: do not set -w for vmlinux.o modpost
The -w option is meaningless for the first pass of modpost (vmlinux.o).

We know there are unresolved symbols in vmlinux.o, hence we skip
check_exports() and other checks when mod->is_vmlinux is set.

See the following part in the for-loop.

    if (mod->is_vmlinux || mod->from_dump)
            continue;

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25 05:17:38 +09:00

166 lines
4.7 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
# ===========================================================================
# Module versions
# ===========================================================================
#
# Stage one of module building created the following:
# a) The individual .o files used for the module
# b) A <module>.o file which is the .o files above linked together
# c) A <module>.mod file, listing the name of the preliminary <module>.o file,
# plus all .o files
# d) modules.order, which lists all the modules
# Stage 2 is handled by this file and does the following
# 1) Find all modules listed in modules.order
# 2) modpost is then used to
# 3) create one <module>.mod.c file pr. module
# 4) create one Module.symvers file with CRC for all exported symbols
# Step 3 is used to place certain information in the module's ELF
# section, including information such as:
# Version magic (see include/linux/vermagic.h for full details)
# - Kernel release
# - SMP is CONFIG_SMP
# - PREEMPT is CONFIG_PREEMPT[_RT]
# - GCC Version
# Module info
# - Module version (MODULE_VERSION)
# - Module alias'es (MODULE_ALIAS)
# - Module license (MODULE_LICENSE)
# - See include/linux/module.h for more details
# Step 4 is solely used to allow module versioning in external modules,
# where the CRC of each module is retrieved from the Module.symvers file.
# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
# This is solely useful to speed up test compiles
PHONY := __modpost
__modpost:
include include/config/auto.conf
include $(srctree)/scripts/Kbuild.include
# for ld_flags
include $(srctree)/scripts/Makefile.lib
MODPOST = scripts/mod/modpost \
$(if $(CONFIG_MODVERSIONS),-m) \
$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \
$(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
-o $@
ifdef MODPOST_VMLINUX
quiet_cmd_modpost = MODPOST $@
cmd_modpost = $(MODPOST) $<
vmlinux.symvers: vmlinux.o
$(call cmd,modpost)
__modpost: vmlinux.symvers
else
ifeq ($(KBUILD_EXTMOD),)
input-symdump := vmlinux.symvers
output-symdump := modules-only.symvers
quiet_cmd_cat = GEN $@
cmd_cat = cat $(real-prereqs) > $@
ifneq ($(wildcard vmlinux.symvers),)
__modpost: Module.symvers
Module.symvers: vmlinux.symvers modules-only.symvers FORCE
$(call if_changed,cat)
targets += Module.symvers
endif
else
# set src + obj - they may be used in the modules's Makefile
obj := $(KBUILD_EXTMOD)
src := $(obj)
# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
$(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
# modpost option for external modules
MODPOST += -e
input-symdump := Module.symvers $(KBUILD_EXTRA_SYMBOLS)
output-symdump := $(KBUILD_EXTMOD)/Module.symvers
endif
# modpost options for modules (both in-kernel and external)
MODPOST += \
$(addprefix -i ,$(wildcard $(input-symdump))) \
$(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \
$(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N)
# 'make -i -k' ignores compile errors, and builds as many modules as possible.
ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
MODPOST += -n
endif
# Clear VPATH to not search for *.symvers in $(srctree). Check only $(objtree).
VPATH :=
$(input-symdump):
@echo >&2 'WARNING: Symbol version dump "$@" is missing.'
@echo >&2 ' Modules may not have dependencies or modversions.'
ifdef CONFIG_LTO_CLANG
# With CONFIG_LTO_CLANG, .o files might be LLVM bitcode, so we need to run
# LTO to compile them into native code before running modpost
prelink-ext := .lto
quiet_cmd_cc_lto_link_modules = LTO [M] $@
cmd_cc_lto_link_modules = \
$(LD) $(ld_flags) -r -o $@ \
$(shell [ -s $(@:.lto.o=.o.symversions) ] && \
echo -T $(@:.lto.o=.o.symversions)) \
--whole-archive $^
%.lto.o: %.o
$(call if_changed,cc_lto_link_modules)
endif
modules := $(sort $(shell cat $(MODORDER)))
# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined symbols
ifneq ($(KBUILD_MODPOST_WARN),)
MODPOST += -w
endif
# Read out modules.order to pass in modpost.
# Otherwise, allmodconfig would fail with "Argument list too long".
quiet_cmd_modpost = MODPOST $@
cmd_modpost = sed 's/\.ko$$/$(prelink-ext)\.o/' $< | $(MODPOST) -T -
$(output-symdump): $(MODORDER) $(input-symdump) $(modules:.ko=$(prelink-ext).o) FORCE
$(call if_changed,modpost)
targets += $(output-symdump)
__modpost: $(output-symdump)
ifneq ($(KBUILD_MODPOST_NOFINAL),1)
$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
endif
PHONY += FORCE
FORCE:
existing-targets := $(wildcard $(sort $(targets)))
-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
endif
.PHONY: $(PHONY)