From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-x549.google.com ([2607:f8b0:4864:20::549]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nPhQE-005pt7-0F for linux-um@lists.infradead.org; Thu, 03 Mar 2022 09:06:55 +0000 Received: by mail-pg1-x549.google.com with SMTP id bj8-20020a056a02018800b0035ec8c16f0bso2486516pgb.11 for ; Thu, 03 Mar 2022 01:06:52 -0800 (PST) Date: Thu, 3 Mar 2022 17:06:42 +0800 Message-Id: <20220303090643.241747-1-davidgow@google.com> Mime-Version: 1.0 Subject: [PATCH] um: clang: Strip out -mno-global-merge from USER_CFLAGS From: David Gow List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: Kees Cook Cc: David Gow , Jeff Dike , Richard Weinberger , Anton Ivanov , Masahiro Yamada , Nick Desaulniers , Nathan Chancellor , linux-um@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-kselftest@vger.kernel.org, kunit-dev@googlegroups.com, llvm@lists.linux.dev, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org The things built with USER_CFLAGS don't seem to recognise it as a compiler option, and print a warning: clang: warning: argument unused during compilation: '-mno-global-merge' [-Wunused-command-line-argument] Fixes: 744814d2fa ("um: Allow builds with Clang") Signed-off-by: David Gow --- This warning shows up after merging: https://lore.kernel.org/lkml/20220227184517.504931-6-keescook@chromium.org/ I'm not 100% sure why this is necessary, but it does seem to work. All the attempts to get rid of -mno-global-merge entirely have been met with skepticism, but I'm guessing that it's not a problem for just the UML "user" files, as they shouldn't(?) interact too much with modules. arch/um/Makefile | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/um/Makefile b/arch/um/Makefile index f2fe63bfd819..320b09cd513c 100644 --- a/arch/um/Makefile +++ b/arch/um/Makefile @@ -75,6 +75,10 @@ USER_CFLAGS = $(patsubst $(KERNEL_DEFINES),,$(patsubst -I%,,$(KBUILD_CFLAGS))) \ -D_FILE_OFFSET_BITS=64 -idirafter $(srctree)/include \ -idirafter $(objtree)/include -D__KERNEL__ -D__UM_HOST__ +ifdef CONFIG_CC_IS_CLANG +USER_CFLAGS := $(patsubst -mno-global-merge,,$(USER_CFLAGS)) +endif + #This will adjust *FLAGS accordingly to the platform. include $(srctree)/$(ARCH_DIR)/Makefile-os-$(OS) -- 2.35.1.616.g0bdcbb4464-goog _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um