x86/build: Keep local relocations with ld.lld
[ Upstream commit 7c21383f3429dd70da39c0c7f1efa12377a47ab6 ]
The LLVM linker (ld.lld) defaults to removing local relocations, which
causes KASLR boot failures. ld.bfd and ld.gold already handle this
correctly. This adds the explicit instruction "--discard-none" during
the link phase. There is no change in output for ld.bfd and ld.gold,
but ld.lld now produces an image with all the needed relocations.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: clang-built-linux@googlegroups.com
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190404214027.GA7324@beast
Link: https://github.com/ClangBuiltLinux/linux/issues/404
Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index b5226a0..2996a1d 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -47,7 +47,7 @@
export BITS
ifdef CONFIG_X86_NEED_RELOCS
- LDFLAGS_vmlinux := --emit-relocs
+ LDFLAGS_vmlinux := --emit-relocs --discard-none
endif
#