linux/scripts/Makefile.modpost
Matthew Maurer fc7d5e3210 modpost: Produce extended MODVERSIONS information
Generate both the existing modversions format and the new extended one
when running modpost. Presence of this metadata in the final .ko is
guarded by CONFIG_EXTENDED_MODVERSIONS.

We no longer generate an error on long symbols in modpost if
CONFIG_EXTENDED_MODVERSIONS is set, as they can now be appropriately
encoded in the extended section. These symbols will be skipped in the
previous encoding. An error will still be generated if
CONFIG_EXTENDED_MODVERSIONS is not set.

Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Matthew Maurer <mmaurer@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2025-01-11 01:25:26 +09:00

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4.8 KiB
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# 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 per 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.
PHONY := __modpost
__modpost:
include $(objtree)/include/config/auto.conf
include $(srctree)/scripts/Kbuild.include
MODPOST = $(objtree)/scripts/mod/modpost
modpost-args = \
$(if $(CONFIG_MODULES),-M) \
$(if $(CONFIG_MODVERSIONS),-m) \
$(if $(CONFIG_EXTENDED_MODVERSIONS),-x) \
$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \
$(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
$(if $(KBUILD_MODPOST_WARN),-w) \
$(if $(KBUILD_NSDEPS),-d modules.nsdeps) \
$(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) \
$(if $(findstring 1, $(KBUILD_EXTRA_WARN)),-W) \
-o $@
modpost-deps := $(MODPOST)
# 'make -i -k' ignores compile errors, and builds as many modules as possible.
ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
modpost-args += -n
endif
# Read out modules.order to pass in modpost.
# Otherwise, allmodconfig would fail with "Argument list too long".
ifdef KBUILD_MODULES
modpost-args += -T modules.order
modpost-deps += modules.order
endif
ifeq ($(KBUILD_EXTMOD),)
# Generate the list of in-tree objects in vmlinux
# ---------------------------------------------------------------------------
# This is used to retrieve symbol versions generated by genksyms.
ifdef CONFIG_MODVERSIONS
vmlinux.symvers Module.symvers: .vmlinux.objs
endif
# Ignore libgcc.a
# Some architectures do '$(CC) --print-libgcc-file-name' to borrow libgcc.a
# from the toolchain, but there is no EXPORT_SYMBOL in it.
quiet_cmd_vmlinux_objs = GEN $@
cmd_vmlinux_objs = \
for f in $(real-prereqs); do \
case $${f} in \
*libgcc.a) ;; \
*) $(AR) t $${f} ;; \
esac \
done > $@
targets += .vmlinux.objs
.vmlinux.objs: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
$(call if_changed,vmlinux_objs)
ifdef CONFIG_TRIM_UNUSED_KSYMS
ksym-wl := $(CONFIG_UNUSED_KSYMS_WHITELIST)
ksym-wl := $(if $(filter-out /%, $(ksym-wl)),$(if $(wildcard $(ksym-wl)),,$(srctree)/))$(ksym-wl)
modpost-args += -t $(addprefix -u , $(ksym-wl))
modpost-deps += $(ksym-wl)
endif
ifeq ($(wildcard vmlinux.o),)
missing-input := vmlinux.o
output-symdump := modules-only.symvers
else
modpost-args += vmlinux.o
modpost-deps += vmlinux.o
output-symdump := $(if $(KBUILD_MODULES), Module.symvers, vmlinux.symvers)
endif
else
# set src + obj - they may be used in the modules's Makefile
obj := .
src := $(srcroot)
# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
include $(kbuild-file)
output-symdump := Module.symvers
ifeq ($(wildcard $(objtree)/Module.symvers),)
missing-input := $(objtree)/Module.symvers
else
modpost-args += -i $(objtree)/Module.symvers
modpost-deps += $(objtree)/Module.symvers
endif
modpost-args += -e $(addprefix -i , $(KBUILD_EXTRA_SYMBOLS))
endif # ($(KBUILD_EXTMOD),)
quiet_cmd_modpost = MODPOST $@
cmd_modpost = \
$(if $(missing-input), \
echo >&2 "WARNING: $(missing-input) is missing."; \
echo >&2 " Modules may not have dependencies or modversions."; \
echo >&2 " You may get many unresolved symbol errors."; \
echo >&2 " You can set KBUILD_MODPOST_WARN=1 to turn errors into warning"; \
echo >&2 " if you want to proceed at your own risk.";) \
$(MODPOST) $(modpost-args)
targets += $(output-symdump)
$(output-symdump): $(modpost-deps) FORCE
$(call if_changed,modpost)
__modpost: $(output-symdump)
PHONY += FORCE
FORCE:
existing-targets := $(wildcard $(sort $(targets)))
-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
.PHONY: $(PHONY)