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Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hvfoI-0006F9-Ul; Thu, 08 Aug 2019 10:38:18 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hvfoC-0006Eo-Q6 for linux-arm-kernel@lists.infradead.org; Thu, 08 Aug 2019 10:38:14 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C465028; Thu, 8 Aug 2019 03:38:11 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D9D2F3F694; Thu, 8 Aug 2019 03:38:10 -0700 (PDT) Date: Thu, 8 Aug 2019 11:38:08 +0100 From: Mark Rutland To: Qian Cai Subject: Re: [PATCH] arm64/cache: silence -Woverride-init warnings Message-ID: <20190808103808.GC46901@lakrids.cambridge.arm.com> References: <20190808032916.879-1-cai@lca.pw> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190808032916.879-1-cai@lca.pw> User-Agent: Mutt/1.11.1+11 (2f07cb52) (2018-12-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190808_033812_892963_B19A8740 X-CRM114-Status: GOOD ( 16.52 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: catalin.marinas@arm.com, will@kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, clang-built-linux@googlegroups.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Aug 07, 2019 at 11:29:16PM -0400, Qian Cai wrote: > The commit 155433cb365e ("arm64: cache: Remove support for ASID-tagged > VIVT I-caches") introduced some compiation warnings from GCC (and > Clang) with -Winitializer-overrides), > > arch/arm64/kernel/cpuinfo.c:38:26: warning: initialized field > overwritten [-Woverride-init] > [ICACHE_POLICY_VIPT] = "VIPT", > ^~~~~~ > arch/arm64/kernel/cpuinfo.c:38:26: note: (near initialization for > 'icache_policy_str[2]') > arch/arm64/kernel/cpuinfo.c:39:26: warning: initialized field > overwritten [-Woverride-init] > [ICACHE_POLICY_PIPT] = "PIPT", > ^~~~~~ > arch/arm64/kernel/cpuinfo.c:39:26: note: (near initialization for > 'icache_policy_str[3]') > arch/arm64/kernel/cpuinfo.c:40:27: warning: initialized field > overwritten [-Woverride-init] > [ICACHE_POLICY_VPIPT] = "VPIPT", > ^~~~~~~ > arch/arm64/kernel/cpuinfo.c:40:27: note: (near initialization for > 'icache_policy_str[0]') > > because it initializes icache_policy_str[0 ... 3] twice. Since > arm64 developers are keen to keep the style of initializing a static > array with a non-zero pattern first, just disable those warnings for > both GCC and Clang of this file. > > Fixes: 155433cb365e ("arm64: cache: Remove support for ASID-tagged VIVT I-caches") > Signed-off-by: Qian Cai This is _not_ a fix, and should not require backporting to stable trees. What about all the other instances that we have in mainline? I really don't think that we need to go down this road; we're just going to end up adding this to every file that happens to include a header using this scheme... Please just turn this off by default for clang. If we want to enable this, we need a mechanism to permit overridable assignments as we use range initializers for. Thanks, Mark. > --- > arch/arm64/kernel/Makefile | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile > index 478491f07b4f..397ed5f7be1e 100644 > --- a/arch/arm64/kernel/Makefile > +++ b/arch/arm64/kernel/Makefile > @@ -11,6 +11,9 @@ CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE) > CFLAGS_REMOVE_insn.o = $(CC_FLAGS_FTRACE) > CFLAGS_REMOVE_return_address.o = $(CC_FLAGS_FTRACE) > > +CFLAGS_cpuinfo.o += $(call cc-disable-warning, override-init) > +CFLAGS_cpuinfo.o += $(call cc-disable-warning, initializer-overrides) > + > # Object file lists. > obj-y := debug-monitors.o entry.o irq.o fpsimd.o \ > entry-fpsimd.o process.o ptrace.o setup.o signal.o \ > -- > 2.20.1 (Apple Git-117) > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel