Commit 86556392 authored Dec 02, 2016 by Nicolas Pitre Committed by Linus Torvalds Dec 02, 2016

kbuild: fix building bzImage with CONFIG_TRIM_UNUSED_KSYMS enabled



When building a specific target such as bzImage, modules aren't normally
built.  However if CONFIG_TRIM_UNUSED_KSYMS is enabled, no built modules
means none of the exported symbols are used and therefore they will all
be trimmed away from the final kernel.  A subsequent "make modules" will
fail because modpost cannot find the needed symbols for those modules in
the kernel binary.

Let's make sure modules are also built whenever CONFIG_TRIM_UNUSED_KSYMS
is enabled and that the kernel binary is properly rebuilt accordingly.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 8dc0f265

Makefile

+8 −1

Original line number	Diff line number	Diff line
		@@ -607,6 +607,13 @@ else
		include/config/auto.conf: ;
		endif # $(dot-config)

		# For the kernel to actually contain only the needed exported symbols,
		# we have to build modules as well to determine what those symbols are.
		# (this can be evaluated only once include/config/auto.conf has been included)
		ifdef CONFIG_TRIM_UNUSED_KSYMS
		KBUILD_MODULES := 1
		endif

		# The all: target is the default when no target is given on the
		# command line.
		# This allow a user to issue only 'make' to build a kernel including modules
		@@ -944,7 +951,7 @@ ifdef CONFIG_GDB_SCRIPTS
		endif
		ifdef CONFIG_TRIM_UNUSED_KSYMS
		$(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh \
		"$(MAKE) KBUILD_MODULES=1 -f $(srctree)/Makefile vmlinux_prereq"
		"$(MAKE) -f $(srctree)/Makefile vmlinux"
		endif

		# standalone target for easier testing