From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9AD1C433E3 for ; Wed, 27 May 2020 13:45:53 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 79E3B207D8 for ; Wed, 27 May 2020 13:45:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="FWH+gj7g" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 79E3B207D8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=fnHQosCWBcDHABGjToJnEVSl58sCeW0m9EDlpr2K8to=; b=FWH+gj7gAGcFo91+yHNuReaLd xtuyklukbS7486KImi20rCttCE8u3cf4EY5wy0T4uQznRQD2xUK5hm5YshS6sRrZjRD1W9WmEASN3 j2eIRF8GQjboDp33x03uz38Mof4iLyAlonBkO5n6z8TABxG4tyuTNo6nOLGr51odF/3CMZ3oj7Rxg 2AKcjQ3Pe1gdiUjDKuXMG2lttuxB2MbWslZ57/TBpDfxHB7gEEi1lp3Hn4nF0U4IdpDgfz9G747Wj guQlE+NkDq4FeucQ95OMmAGLVuw6wp8XD8d++JkzO+T1SXhRU8vdhM/yfcb49H+mj+Xe0AoPsLJrM illQfmHoA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jdwNK-00017Y-0g; Wed, 27 May 2020 13:45:42 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jdwNG-00016V-TJ for linux-arm-kernel@lists.infradead.org; Wed, 27 May 2020 13:45:40 +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 CBFFB55D; Wed, 27 May 2020 06:45:36 -0700 (PDT) Received: from [10.57.2.168] (unknown [10.57.2.168]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C0FB23F6C4; Wed, 27 May 2020 06:45:34 -0700 (PDT) Subject: Re: [PATCH] arm64: vdso32: force vdso32 to be compiled as -marm To: Nick Desaulniers , Catalin Marinas , Will Deacon References: <20200526173117.155339-1-ndesaulniers@google.com> From: Robin Murphy Message-ID: <2f58c2a4-0f37-d507-7767-00161c6b5d98@arm.com> Date: Wed, 27 May 2020 14:45:32 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200526173117.155339-1-ndesaulniers@google.com> Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200527_064538_987466_DE02FFF6 X-CRM114-Status: GOOD ( 17.80 ) 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: Naohiro Aota , Stephen Boyd , Masahiro Yamada , linux-kernel@vger.kernel.org, Manoj Gupta , Luis Lozano , Nathan Chancellor , Vincenzo Frascino , linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2020-05-26 18:31, Nick Desaulniers wrote: > Custom toolchains that modify the default target to -mthumb cannot > compile the arm64 compat vdso32, as > arch/arm64/include/asm/vdso/compat_gettimeofday.h > contains assembly that's invalid in -mthumb. Force the use of -marm, > always. FWIW, this seems suspicious - the only assembly instructions I see there are SWI(SVC), MRRC, and a MOV, all of which exist in Thumb for the -march=armv7a baseline that we set. On a hunch, I've just bodged "VDSO_CFLAGS += -mthumb" into my tree and built a Thumb VDSO quite happily with Ubuntu 19.04's gcc-arm-linux-gnueabihf. What was the actual failure you saw? Robin. > Link: https://bugs.chromium.org/p/chromium/issues/detail?id=1084372 > Cc: Stephen Boyd > Reported-by: Luis Lozano > Tested-by: Manoj Gupta > Signed-off-by: Nick Desaulniers > --- > Surgeon General's Warning: changing the compiler defaults is not > recommended and can lead to spooky bugs that are hard to reproduce > upstream. > > arch/arm64/kernel/vdso32/Makefile | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile > index 3964738ebbde..c449a293d81e 100644 > --- a/arch/arm64/kernel/vdso32/Makefile > +++ b/arch/arm64/kernel/vdso32/Makefile > @@ -104,6 +104,8 @@ VDSO_CFLAGS += -D__uint128_t='void*' > # (on GCC 4.8 or older, there is unfortunately no way to silence this warning) > VDSO_CFLAGS += $(call cc32-disable-warning,shift-count-overflow) > VDSO_CFLAGS += -Wno-int-to-pointer-cast > +# Force vdso to be compiled in ARM mode, not THUMB. > +VDSO_CFLAGS += -marm > > VDSO_AFLAGS := $(VDSO_CAFLAGS) > VDSO_AFLAGS += -D__ASSEMBLY__ > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel