From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3513117-1517487368-2-16512225893691363224 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.001, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='com', MailFrom='org' X-Spam-charsets: X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1517487368; b=s14tbLbPFuPdYzaqQ/+CESoQeExXGomX9p7DLFhkKZ2hfVr dzaJdlNlWCdtC8oLyQtfrq67KfEKvYTtG9ya4FkE0p1QcLMWV+iQh0g4J7h2VDOR fnWRNHyiDk64Fhnsk3UZmx02lauVbA7ZKReLS75QpFO6Ro9acXAmbwzcYD9dVqub ZdlIghy0WSSaYeMqUfzaoqj5PSdGzEibc+JK3hNFriIbQVDi48AFszbIKgDNpu4t EoVHrWGh5G3FLE6KtXtCUr4Yit6xLgOAPaylE1UC7jlWjxuHnrKgaj8lMPYy/F0J ksL1GMEGwLissM6/8NAdaQ/ArQy/2FpNc0hMG/A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id:sender :list-id; s=arctest; t=1517487368; bh=1bDfXvbrmkkcPVrOyNqklmDrV5 /kUBiauoDA1CpEVoc=; b=qaFpmLDT7qaVVFDj7EsPtnw6jXjnWsMr4q9ZoBJfxy Cuoza/Hl8/7wdvIzzWBgRgJB6+2HqY4DNtvp9V0RyABRZh99KJGSr/GCXIknQ98V 4o9ZqwcvqmI57e/T9Isf0v7CyPZSmxuxxsqVXV2lzCOO0XRkbJOUxoHkq7AH8aVS mN43B9qteJa7VtWh+aA8fWQ8zWOTBUiI2QZUkc3VBmkYK7NGRoL8R5/2wKDqUxpr z3yUdoOhldGOqdEBXge86JUjnLqgkEV2phkdyB3YI9cIVKEvCiy0QVBJNNDSxUqk OTR2DkCmBAyOb4bvklRQkG8s+bcsqOA+yeKVfvdcI7jw== ARC-Authentication-Results: i=1; mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=suse.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=suse.com header.result=pass header_is_org_domain=yes Authentication-Results: mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=suse.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=suse.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752030AbeBAMQG (ORCPT ); Thu, 1 Feb 2018 07:16:06 -0500 Received: from mx2.suse.de ([195.135.220.15]:32971 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751949AbeBAMQF (ORCPT ); Thu, 1 Feb 2018 07:16:05 -0500 From: Juergen Gross To: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org Cc: boris.ostrovsky@oracle.com, Juergen Gross , stable@vger.kernel.org Subject: [PATCH] x86/xen: init %gs very early to avoid page faults with stack protector Date: Thu, 1 Feb 2018 13:16:01 +0100 Message-Id: <20180201121601.1268-1-jgross@suse.com> X-Mailer: git-send-email 2.13.6 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: When running as Xen pv guest %gs is initialized some time after C code is started. Depending on stack protector usage this might be too late, resulting in page faults. So setup %gs and MSR_GS_BASE in assembly code already. Cc: stable@vger.kernel.org Signed-off-by: Juergen Gross --- arch/x86/xen/xen-head.S | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S index 497cc55a0c16..b47d87076efb 100644 --- a/arch/x86/xen/xen-head.S +++ b/arch/x86/xen/xen-head.S @@ -9,7 +9,9 @@ #include #include +#include #include +#include #include #include @@ -35,6 +37,18 @@ ENTRY(startup_xen) mov %_ASM_SI, xen_start_info mov $init_thread_union+THREAD_SIZE, %_ASM_SP + /* Set up %gs. + * + * The base of %gs always points to the bottom of the irqstack + * union. If the stack protector canary is enabled, it is + * located at %gs:40. Note that, on SMP, the boot cpu uses + * init data section till per cpu areas are set up. + */ + movl $MSR_GS_BASE,%ecx + movq $INIT_PER_CPU_VAR(irq_stack_union),%rax + cdq + wrmsr + jmp xen_start_kernel END(startup_xen) __FINIT -- 2.13.6