[PATCH 05/22] objtool: Fix CONFIG_OBJTOOL_WERROR for vmlinux.o

From: Josh Poimboeuf
Date: Mon Mar 24 2025 - 17:57:02 EST


With (!X86_KERNEL_IBT && !LTO_CLANG && NOINSTR_VALIDATION), objtool runs
on both translation units and vmlinux.o. With CONFIG_OBJTOOL_WERROR,
the TUs get --Werror but vmlinux.o doesn't. Fix that.

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
scripts/Makefile.vmlinux_o | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o
index 0b6e2ebf60dc..f476f5605029 100644
--- a/scripts/Makefile.vmlinux_o
+++ b/scripts/Makefile.vmlinux_o
@@ -30,12 +30,20 @@ endif
# objtool for vmlinux.o
# ---------------------------------------------------------------------------
#
-# For LTO and IBT, objtool doesn't run on individual translation units.
-# Run everything on vmlinux instead.
+# For delay-objtool (IBT or LTO), objtool doesn't run on individual translation
+# units. Instead it runs on vmlinux.o.
+#
+# For !delay-objtool + CONFIG_NOINSTR_VALIDATION, it runs on both translation
+# units and vmlinux.o, with the latter only used for noinstr/unret validation.

objtool-enabled := $(or $(delay-objtool),$(CONFIG_NOINSTR_VALIDATION))

-vmlinux-objtool-args-$(delay-objtool) += $(objtool-args-y)
+ifeq ($(delay-objtool),y)
+vmlinux-objtool-args-y += $(objtool-args-y)
+else
+vmlinux-objtool-args-$(CONFIG_OBJTOOL_WERROR) += --Werror
+endif
+
vmlinux-objtool-args-$(CONFIG_GCOV_KERNEL) += --no-unreachable
vmlinux-objtool-args-$(CONFIG_NOINSTR_VALIDATION) += --noinstr \
$(if $(or $(CONFIG_MITIGATION_UNRET_ENTRY),$(CONFIG_MITIGATION_SRSO)), --unret)
--
2.48.1