Commit f2c356d1 authored Sep 17, 2025 by Josh Poimboeuf

kbuild,objtool: Defer objtool validation step for CONFIG_KLP_BUILD



In preparation for klp-build, defer objtool validation for
CONFIG_KLP_BUILD kernels until the final pre-link archive (e.g.,
vmlinux.o, module-foo.o) is built.  This will simplify the process of
generating livepatch modules.

Delayed objtool is generally preferred anyway, and is already standard
for IBT and LTO.  Eventually the per-translation-unit mode will be
phased out.

Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

parent 7ae60ff0

scripts/Makefile.lib

+1 −1

Original line number	Diff line number	Diff line
		@@ -197,7 +197,7 @@ objtool-args = $(objtool-args-y) \
		$(if $(delay-objtool), --link) \
		$(if $(part-of-module), --module)

		delay-objtool := $(or $(CONFIG_LTO_CLANG),$(CONFIG_X86_KERNEL_IBT))
		delay-objtool := $(or $(CONFIG_LTO_CLANG),$(CONFIG_X86_KERNEL_IBT),$(CONFIG_KLP_BUILD))

		cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool-args) $@)
		cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd)

scripts/link-vmlinux.sh

+2 −1

Original line number	Diff line number	Diff line
		@@ -60,7 +60,8 @@ vmlinux_link()
		# skip output file argument
		shift

		if is_enabled CONFIG_LTO_CLANG \|\| is_enabled CONFIG_X86_KERNEL_IBT; then
		if is_enabled CONFIG_LTO_CLANG \|\| is_enabled CONFIG_X86_KERNEL_IBT \|\|
		is_enabled CONFIG_KLP_BUILD; then
		# Use vmlinux.o instead of performing the slow LTO link again.
		objs=vmlinux.o
		libs=