Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Arnd Bergmann <arnd@kernel.org>
To:     Masahiro Yamada <masahiroy@kernel.org>,
        Marco Elver <elver@google.com>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Alexander Potapenko <glider@google.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nicolas Schier <nicolas@fjasle.eu>, Tom Rix <trix@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        kasan-dev@googlegroups.com, linux-kbuild@vger.kernel.org,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Subject: [PATCH] [v2] kasan: remove hwasan-kernel-mem-intrinsic-prefix=1 for clang-14
Date:   Tue, 18 Apr 2023 14:23:35 +0200
Message-Id: <20230418122350.1646391-1-arnd@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Arnd Bergmann <arnd@arndb.de>

Some unknown -mllvm options (i.e. those starting with the letter "h")
don't cause an error to be returned by clang, so the cc-option helper
adds the unknown hwasan-kernel-mem-intrinsic-prefix=1 flag to CFLAGS
with compilers that are new enough for hwasan but too old for this option.

This causes a rather unreadable build failure:

fixdep: error opening file: scripts/mod/.empty.o.d: No such file or directory
make[4]: *** [/home/arnd/arm-soc/scripts/Makefile.build:252: scripts/mod/empty.o] Error 2
fixdep: error opening file: scripts/mod/.devicetable-offsets.s.d: No such file or directory
make[4]: *** [/home/arnd/arm-soc/scripts/Makefile.build:114: scripts/mod/devicetable-offsets.s] Error 2

Add a version check to only allow this option with clang-15, gcc-13
or later versions.

Fixes: 51287dcb00cc ("kasan: emit different calls for instrumentable memintrinsics")
Link: https://lore.kernel.org/all/CANpmjNMwYosrvqh4ogDO8rgn+SeDHM2b-shD21wTypm_6MMe=g@mail.gmail.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v2: use one-line version check for both clang and gcc, clarify changelog text
---
 scripts/Makefile.kasan | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
index c186110ffa20..390658a2d5b7 100644
--- a/scripts/Makefile.kasan
+++ b/scripts/Makefile.kasan
@@ -69,7 +69,9 @@ CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
 		$(instrumentation_flags)
 
 # Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*().
+ifeq ($(call clang-min-version, 150000)$(call gcc-min-version, 130000),y)
 CFLAGS_KASAN += $(call cc-param,hwasan-kernel-mem-intrinsic-prefix=1)
+endif
 
 endif # CONFIG_KASAN_SW_TAGS
 
-- 
2.39.2