mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-08-04 16:25:34 +00:00
269a535ca9
The full build runs modpost twice, first for vmlinux.o and second for modules. The first pass dumps all the vmlinux symbols into Module.symvers, but the second pass parses vmlinux again instead of reusing the dump file, presumably because it needs to avoid accumulating stale symbols. Loading symbol info from a dump file is faster than parsing an ELF object. Besides, modpost deals with various issues to parse vmlinux in the second pass. A solution is to make the first pass dumps symbols into a separate file, vmlinux.symvers. The second pass reads it, and parses module .o files. The merged symbol information is dumped into Module.symvers in the same way as before. This makes further modpost cleanups possible. Also, it fixes the problem of 'make vmlinux', which previously overwrote Module.symvers, throwing away module symbols. I slightly touched scripts/link-vmlinux.sh so that vmlinux is re-linked when you cross this commit. Otherwise, vmlinux.symvers would not be generated. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
119 lines
3.4 KiB
Text
119 lines
3.4 KiB
Text
# 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_WARN can be set to avoid error out in case of undefined
|
|
# symbols in the final module linking stage
|
|
# 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 scripts/Kbuild.include
|
|
|
|
MODPOST = scripts/mod/modpost \
|
|
$(if $(CONFIG_MODVERSIONS),-m) \
|
|
$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \
|
|
$(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
|
|
$(if $(KBUILD_MODPOST_WARN),-w) \
|
|
-o $@
|
|
|
|
ifdef MODPOST_VMLINUX
|
|
|
|
quiet_cmd_modpost = MODPOST $@
|
|
cmd_modpost = $(MODPOST) $<
|
|
|
|
vmlinux.symvers: vmlinux.o
|
|
$(call cmd,modpost)
|
|
|
|
__modpost: vmlinux.symvers
|
|
|
|
else
|
|
|
|
MODPOST += -s \
|
|
$(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS))
|
|
|
|
ifeq ($(KBUILD_EXTMOD),)
|
|
|
|
input-symdump := vmlinux.symvers
|
|
output-symdump := Module.symvers
|
|
|
|
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 += \
|
|
$(addprefix -i ,$(input-symdump)) \
|
|
$(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
|
|
|
|
# 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$$/o/' $(MODORDER) | $(MODPOST) -T -
|
|
|
|
$(output-symdump): FORCE
|
|
$(call cmd,modpost)
|
|
|
|
__modpost: $(output-symdump)
|
|
ifneq ($(KBUILD_MODPOST_NOFINAL),1)
|
|
$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
|
|
endif
|
|
|
|
PHONY += FORCE
|
|
FORCE:
|
|
|
|
endif
|
|
|
|
.PHONY: $(PHONY)
|