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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 C412CC433DB for ; Sat, 6 Mar 2021 21:42:35 +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 64DB5650AC for ; Sat, 6 Mar 2021 21:42:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 64DB5650AC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xen.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.94384.177945 (Exim 4.92) (envelope-from ) id 1lIegW-0007n5-Co; Sat, 06 Mar 2021 21:42:04 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 94384.177945; Sat, 06 Mar 2021 21:42:04 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lIegW-0007my-8j; Sat, 06 Mar 2021 21:42:04 +0000 Received: by outflank-mailman (input) for mailman id 94384; Sat, 06 Mar 2021 21:42:03 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lIegV-0007mt-0y for xen-devel@lists.xenproject.org; Sat, 06 Mar 2021 21:42:03 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lIegT-0001PC-Hl; Sat, 06 Mar 2021 21:42:01 +0000 Received: from 54-240-197-235.amazon.com ([54.240.197.235] helo=ufe34d9ed68d054.ant.amazon.com) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lIegT-00066t-11; Sat, 06 Mar 2021 21:42:01 +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=xen.org; s=20200302mail; h=Message-Id:Date:Subject:Cc:To:From; bh=VU75K8jemcqWW+CW4IZ/uc+bhcZ1ef0hQsKo4FgR/38=; b=HyLA+aZFi+QgIcIUfhDI7p1/M1 01Qpw5jwR3QF7RNAZCLjtOL/M5z/cSq/d31TBtIRKW+fSeN4PYBLfb8b0qnkM16nKuu4TU178BMWr 0Dlc9vBfsNDPwWoSnVA1Qj8q0zH0NGqM7TnLtCc05FyigOY1jACxb3wRRCgtkJG6+mCk=; From: Julien Grall To: xen-devel@lists.xenproject.org Cc: julien@xen.org, Julien Grall , Andrew Cooper , George Dunlap , Ian Jackson , Jan Beulich , Stefano Stabellini , Wei Liu Subject: [PATCH for-4.15] xen: Bump the minimum version of GCC supported to 4.9 (5.1 on arm64) Date: Sat, 6 Mar 2021 21:41:48 +0000 Message-Id: <20210306214148.27021-1-julien@xen.org> X-Mailer: git-send-email 2.17.1 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. Signed-off-by: Julien Grall --- I don't have a strong opinion on the minimum version for GCC on x86. So this is following Andrew's suggestion and the minimum from Linux. This patch is candidate to 4.15 and backport. This is only a build change and will be low-risk for anyone using newer compiler (5.1+ for arm64 and 4.9 for everyone else). Xen will stop building for anyone using older compiler. But it is better than fighting with codegen issues. --- README | 9 ++++++--- xen/include/xen/compiler.h | 13 +++++++++++++ 2 files changed, 19 insertions(+), 3 deletions(-) diff --git a/README b/README index 8c99c30986c1..5c32c03f2ea1 100644 --- a/README +++ b/README @@ -38,12 +38,15 @@ provided by your OS distributor: * GNU Make v3.80 or later * C compiler and linker: - For x86: - - GCC 4.1.2_20070115 or later + - GCC 4.9 or later - GNU Binutils 2.16.91.0.5 or later or - Clang/LLVM 3.5 or later - - For ARM: - - GCC 4.8 or later + - For ARM 32-bit: + - GCC 4.9 or later + - GNU Binutils 2.24 or later + - For ARM 64-bit: + - GCC 5.1 or later - GNU Binutils 2.24 or later * Development install of zlib (e.g., zlib-dev) * Development install of Python 2.6 or later (e.g., python-dev) diff --git a/xen/include/xen/compiler.h b/xen/include/xen/compiler.h index 0ec0b4698ea7..46779660cc8f 100644 --- a/xen/include/xen/compiler.h +++ b/xen/include/xen/compiler.h @@ -5,6 +5,19 @@ #error Sorry, your compiler is too old/not recognized. #endif +#if CONFIG_CC_IS_GCC +# if CONFIG_GCC_VERSION < 40900 +/* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 */ +# error Sorry, your version of GCC is too old - please use 4.9 or newer. +# elif defined(CONFIG_ARM_64) && CONFIG_GCC_VERSION < 50100 +/* + * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63293 + * https://lore.kernel.org/r/20210107111841.GN1551@shell.armlinux.org.uk + */ +# error Sorry, your version of GCC is too old - please use 5.1 or newer. +# endif +#endif + #define barrier() __asm__ __volatile__("": : :"memory") #define likely(x) __builtin_expect(!!(x),1) -- 2.17.1