From patchwork Fri Nov 25 19:04:51 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Cooper X-Patchwork-Id: 9448035 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 36A1060778 for ; Fri, 25 Nov 2016 19:07:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2336F27B2F for ; Fri, 25 Nov 2016 19:07:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 167D527CF3; Fri, 25 Nov 2016 19:07:10 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 98D6327B2F for ; Fri, 25 Nov 2016 19:07:09 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cALnt-00039k-SL; Fri, 25 Nov 2016 19:04:57 +0000 Received: from mail6.bemta6.messagelabs.com ([193.109.254.103]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cALns-00039e-94 for xen-devel@lists.xen.org; Fri, 25 Nov 2016 19:04:56 +0000 Received: from [85.158.143.35] by server-11.bemta-6.messagelabs.com id 59/07-28490-75B88385; Fri, 25 Nov 2016 19:04:55 +0000 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrFLMWRWlGSWpSXmKPExsXitHRDpG5Yt0W Ewcy/6hZLPi5mcWD0OLr7N1MAYxRrZl5SfkUCa8bpzaUFT7gremd8ZW9gvMXZxcjJISHgL9F6 po0NxGYT0JfY/eITE4gtIqAucbrjIiuIzSyQJ9H58SN7FyMHh7CAk8T2VkmQMIuAqsS6pUfYQ WxeAQ+Jd692s0OMlJM4f/wnM4gtJKAmca3/ElSNoMTJmU9YIEZKSBx88YJ5AiP3LCSpWUhSCx iZVjGqF6cWlaUW6VroJRVlpmeU5CZm5ugaGpjp5aYWFyemp+YkJhXrJefnbmIEhgEDEOxgnH3 Z/xCjJAeTkihvY5tFhBBfUn5KZUZicUZ8UWlOavEhRhkODiUJ3pAuoJxgUWp6akVaZg4wIGHS Ehw8SiK8qp1Aad7igsTc4sx0iNQpRkUpcV4VkD4BkERGaR5cGywKLjHKSgnzMgIdIsRTkFqUm 1mCKv+KUZyDUUmYNw9kPE9mXgnc9FdAi5mAFjv/MAdZXJKIkJJqYJTLOlh2bvWKHsa1+2rznr yJjfh1Unxrkv7MvrXKZ5O5jiiXL79QdEZYzfdtM+fRBRUKj3ldjZTvdL29OrfWqE0w7l/Ow3m ffMrr3OQPxWvP6NWLrGDe6Km7dkWrlcH+3UbqjPnJIl7pfB1rUxYcCdk8Qe76ky2MiaLz8jZ2 Gt+7+zKa14XvuBJLcUaioRZzUXEiAK7anG59AgAA X-Env-Sender: prvs=1308830d3=Andrew.Cooper3@citrix.com X-Msg-Ref: server-15.tower-21.messagelabs.com!1480100693!45123434!1 X-Originating-IP: [66.165.176.89] X-SpamReason: No, hits=0.0 required=7.0 tests=sa_preprocessor: VHJ1c3RlZCBJUDogNjYuMTY1LjE3Ni44OSA9PiAyMDMwMDc=\n, received_headers: No Received headers X-StarScan-Received: X-StarScan-Version: 9.0.16; banners=-,-,- X-VirusChecked: Checked Received: (qmail 42357 invoked from network); 25 Nov 2016 19:04:54 -0000 Received: from smtp.citrix.com (HELO SMTP.CITRIX.COM) (66.165.176.89) by server-15.tower-21.messagelabs.com with RC4-SHA encrypted SMTP; 25 Nov 2016 19:04:54 -0000 X-IronPort-AV: E=Sophos;i="5.31,696,1473120000"; d="scan'208";a="391429331" From: Andrew Cooper To: Xen-devel Date: Fri, 25 Nov 2016 19:04:51 +0000 Message-ID: <1480100691-5589-1-git-send-email-andrew.cooper3@citrix.com> X-Mailer: git-send-email 2.1.4 MIME-Version: 1.0 Cc: Andrew Cooper , Wei Liu , Jan Beulich Subject: [Xen-devel] [PATCH for-4.8] x86/cpu: Reposition stack alignment check X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP As identified during review, using BUG_ON() before `lidt` will result in a triple fault, even on APs. Signed-off-by: Andrew Cooper Reviewed-by: Jan Beulich --- CC: Jan Beulich CC: Wei Liu --- xen/arch/x86/cpu/common.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c index 06ee401..16cf001 100644 --- a/xen/arch/x86/cpu/common.c +++ b/xen/arch/x86/cpu/common.c @@ -643,11 +643,6 @@ void load_system_tables(void) .limit = (IDT_ENTRIES * sizeof(idt_entry_t)) - 1, }; - /* Bottom-of-stack must be 16-byte aligned! */ - BUILD_BUG_ON((sizeof(struct cpu_info) - - offsetof(struct cpu_info, guest_cpu_user_regs.es)) & 0xf); - BUG_ON(system_state != SYS_STATE_early_boot && (stack_bottom & 0xf)); - /* Main stack for interrupts/exceptions. */ tss->rsp0 = stack_bottom; tss->bitmap = IOBMP_INVALID_OFFSET; @@ -672,6 +667,15 @@ void load_system_tables(void) asm volatile ("lidt %0" : : "m" (idtr) ); asm volatile ("ltr %w0" : : "rm" (TSS_ENTRY << 3) ); asm volatile ("lldt %w0" : : "rm" (0) ); + + /* + * Bottom-of-stack must be 16-byte aligned! + * + * Defer checks until exception support is sufficiently set up. + */ + BUILD_BUG_ON((sizeof(struct cpu_info) - + offsetof(struct cpu_info, guest_cpu_user_regs.es)) & 0xf); + BUG_ON(system_state != SYS_STATE_early_boot && (stack_bottom & 0xf)); } /*