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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 41740C433DB for ; Mon, 8 Mar 2021 09:49:59 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 0538C651B9 for ; Mon, 8 Mar 2021 09:49:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0538C651B9 Authentication-Results: mail.kernel.org; dmarc=pass (p=none dis=none) header.from=xenproject.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.94743.178389 (Exim 4.92) (envelope-from ) id 1lJCWM-0004rO-A9; Mon, 08 Mar 2021 09:49:50 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 94743.178389; Mon, 08 Mar 2021 09:49:50 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lJCWM-0004rF-6t; Mon, 08 Mar 2021 09:49:50 +0000 Received: by outflank-mailman (input) for mailman id 94743; Mon, 08 Mar 2021 09:49:49 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lJCWL-0004qv-Ar for xen-devel@lists.xenproject.org; Mon, 08 Mar 2021 09:49:49 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lJCWL-00011S-80 for xen-devel@lists.xenproject.org; Mon, 08 Mar 2021 09:49:49 +0000 Received: from iwj (helo=mariner.uk.xensource.com) by xenbits.xenproject.org with local-bsmtp (Exim 4.92) (envelope-from ) id 1lJCWL-0002aO-6z for xen-devel@lists.xenproject.org; Mon, 08 Mar 2021 09:49:49 +0000 Received: from iwj by mariner.uk.xensource.com with local (Exim 4.89) (envelope-from ) id 1lJCWH-000802-VS; Mon, 08 Mar 2021 09:49:46 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xenproject.org; s=20200302mail; h=References:In-Reply-To:Subject:Cc:To:Date :Message-ID:Content-Transfer-Encoding:Content-Type:MIME-Version:From; bh=PIRSPx7YkhOyrvCXOyzWue5jBQjQwXNmphb8ajewQmE=; b=xA59tDrgRND25cAbQ5yUHBckMW +RafSso2dNKA1xfFxLGI2FstQpS0fKPIOvie4B0qMsGEQlnLouwedFCDfS21TGkBxbzAL+5X6VsOk eMuQLc22HUrJwIOdYBvocLP9Cl4TGCEH2ibMiAHTqyuYm/7PjJkWbU1ygmvU1o4Wu8es=; From: Ian Jackson MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <24645.62265.765339.521102@mariner.uk.xensource.com> Date: Mon, 8 Mar 2021 09:49:45 +0000 To: Julien Grall Cc: xen-devel@lists.xenproject.org, Julien Grall , Andrew Cooper , George Dunlap , Jan Beulich , Stefano Stabellini , Wei Liu Subject: Re: [PATCH for-4.15] xen: Bump the minimum version of GCC supported to 4.9 (5.1 on arm64) In-Reply-To: <20210306214148.27021-1-julien@xen.org> References: <20210306214148.27021-1-julien@xen.org> X-Mailer: VM 8.2.0b under 24.5.1 (i686-pc-linux-gnu) Julien Grall writes ("[PATCH for-4.15] xen: Bump the minimum version of GCC supported to 4.9 (5.1 on arm64)"): > From: Julien Grall > > Compilers older than 4.8 have known codegen issues which can lead to > silent miscompilation: > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 > > Furthermore, pre-4.9 GCC have known bugs (including things like > internal compiler errors on Arm) which would require workaround (I > haven't checked if we have any in Xen). > > The minimum version of GCC to build the hypervisor is now raised to 4.9. > > In addition to that, on arm64, GCC version >= 4.9 and < 5.1 have been > shown to emit memory references beyond the stack pointer, resulting in > memory corruption if an interrupt is taken after the stack pointer has > been adjusted but before the reference has been executed. > > Therefore, the minimum for arm64 is raised to 5.1. How sad. Release-Acked-by: Ian Jackson I don't currently have an opinion about the merits of this change. I'm hoping that the disagreement can be resolved without me having to have one :-). Thanks, Ian.