modpost: generate vmlinux.symvers and reuse it for the second modpost (269a535c) · Commits · 戴 / test

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>

.gitignore

+1 −0

Original line number	Diff line number	Diff line
		@@ -56,6 +56,7 @@ modules.order
		/linux
		/vmlinux
		/vmlinux.32
		/vmlinux.symvers
		/vmlinux-gdb.py
		/vmlinuz
		/System.map

Documentation/dontdiff

+1 −0

Original line number	Diff line number	Diff line
		@@ -251,6 +251,7 @@ vmlinux-*
		vmlinux.aout
		vmlinux.bin.all
		vmlinux.lds
		vmlinux.symvers
		vmlinuz
		voffset.h
		vsyscall.lds

Makefile

+1 −1

Original line number	Diff line number	Diff line
		@@ -1416,7 +1416,7 @@ endif # CONFIG_MODULES
		# make distclean Remove editor backup files, patch leftover files and the like

		# Directories & files removed with 'make clean'
		CLEAN_FILES += include/ksym \
		CLEAN_FILES += include/ksym vmlinux.symvers \
		modules.builtin modules.builtin.modinfo modules.nsdeps

		# Directories & files removed with 'make mrproper'

scripts/Makefile.modpost

+4 −3

Original line number	Diff line number	Diff line
		@@ -55,10 +55,10 @@ ifdef MODPOST_VMLINUX
		quiet_cmd_modpost = MODPOST $@
		cmd_modpost = $(MODPOST) $<

		Module.symvers: vmlinux.o
		vmlinux.symvers: vmlinux.o
		$(call cmd,modpost)

		__modpost: Module.symvers
		__modpost: vmlinux.symvers

		else

		@@ -66,7 +66,8 @@ MODPOST += -s \
		$(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS))

		ifeq ($(KBUILD_EXTMOD),)
		MODPOST += $(wildcard vmlinux)

		input-symdump := vmlinux.symvers
		output-symdump := Module.symvers

		else

scripts/link-vmlinux.sh

+0 −2

Original line number	Diff line number	Diff line
		@@ -218,8 +218,6 @@ on_signals()
		}
		trap on_signals HUP INT QUIT TERM

		#
		#
		# Use "make V=1" to debug this script
		case "${KBUILD_VERBOSE}" in
		1)

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