From bf3c255150619b71badb328c4dab48401a7ed62d Mon Sep 17 00:00:00 2001
From: Sami Tolvanen <samitolvanen@google.com>
Date: Mon, 8 Mar 2021 10:46:56 -0800
Subject: [PATCH] kbuild: Allow LTO to be selected with KASAN_HW_TAGS

While LTO with KASAN is normally not useful, hardware tag-based KASAN
can be used also in production kernels with ARM64_MTE. Therefore, allow
KASAN_HW_TAGS to be selected together with HAS_LTO_CLANG.

Reported-by: Alistair Delva <adelva@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
 arch/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 2bb30673d8e6f..2e7139b39e8f6 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -638,7 +638,7 @@ config HAS_LTO_CLANG
 	depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
 	depends on ARCH_SUPPORTS_LTO_CLANG
 	depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT
-	depends on !KASAN
+	depends on !KASAN || KASAN_HW_TAGS
 	depends on !GCOV_KERNEL
 	help
 	  The compiler and Kconfig options support building with Clang's