From: Ard Biesheuvel <ardb@kernel.org>
Date: Tue, 8 Apr 2025 08:52:56 +0000 (+0200)
Subject: x86/boot/startup: Disable objtool validation for library code
X-Git-Tag: v6.16-rc1~195^2~30^2~28
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d9fa398fe82728ee703ad2bd9cf5247df9626470;p=thirdparty%2Fkernel%2Flinux.git

x86/boot/startup: Disable objtool validation for library code

The library code built under arch/x86/boot/startup is not intended to be
linked into vmlinux but only into the decompressor and/or the EFI stub.

This means objtool validation is not needed here, and may result in
false positive errors for things like missing retpolines.

So disable it for all objects added to lib-y

Tested-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250408085254.836788-10-ardb+git@google.com
---

diff --git a/arch/x86/boot/startup/Makefile b/arch/x86/boot/startup/Makefile
index 73946a3f6b3ba..8919a1cbcb5ae 100644
--- a/arch/x86/boot/startup/Makefile
+++ b/arch/x86/boot/startup/Makefile
@@ -4,3 +4,9 @@ KBUILD_AFLAGS		+= -D__DISABLE_EXPORTS
 
 lib-$(CONFIG_X86_64)		+= la57toggle.o
 lib-$(CONFIG_EFI_MIXED)		+= efi-mixed.o
+
+#
+# Disable objtool validation for all library code, which is intended
+# to be linked into the decompressor or the EFI stub but not vmlinux
+#
+$(patsubst %.o,$(obj)/%.o,$(lib-y)): OBJECT_FILES_NON_STANDARD := y