From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3617261-1517488844-2-8691492486265954517 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=1517488843; b=HeGh0+TivY0DkWgZoGkDqHQsHSC6KvqqqtnsOfPh1dYvGq0 QTiRj0fKEmod4lr6D88W8sMvr+KgSBukUXS4aETcxnS+IuQNXyhTuc7qtU6A7XnU Ho+VSvmaM7ZpWXGFC1UqGKuAZ6sZj55MHENj0qjB7V+ZGzpEQDSfpDrQXtRDKQnL wsBdjdKkUCZI0LimHqIaPJ4u0ymYy87/tqlC7IKs5Y0LZqGYVczwDdpc+UvIhgO1 qXa8xU4uJqLSUQggaZPRdflYGHErQEKGWHXgMK0xdAB1eXI7OTWWKaI1jlDoYnwr PADbp2pdzdSdtR7KW1I6v7mLAr7AcSpIAGIEnKA== 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=1517488843; bh=HUJFbB2uQYZ7Nus1r1m2ud5hqr kGK5JBhjIdQBpu+vI=; b=VfZJwpCFOG1x8+tzT2dMM+e3duitRM6QohJ5Y5BuWW obhmA8OS7V5p4KvNMKpNVd2+ffx3cOBjTqbQU55vxvIRjY1v1HX/IlsNStXzC92f S6HbVV0YExcw894tK+WRmj6+JVC8j8SUYhpMHph8yA4id+kBOyoKFOsZb7ynCpwh PGwFiXiFMaxVUhd2Xzi9Yz3jvpp9BuL6MaXZEstCtdrQDiDt/PcRspk7vXQCljJz eJ7uU7oogR0vrZQ8CvY2aQgsApTM1u6y2rx0qA2vrl5lRP22tJTzw7w9hY2Ale5m jQIe2kWUq7IDEmUMGp7g7aizI5zA+ZINO5BnU5sQrXLQ== ARC-Authentication-Results: i=1; mx4.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: mx4.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 S1752263AbeBAMk0 (ORCPT ); Thu, 1 Feb 2018 07:40:26 -0500 Received: from mx2.suse.de ([195.135.220.15]:35954 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752516AbeBAMkW (ORCPT ); Thu, 1 Feb 2018 07:40:22 -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 v2] x86/xen: init %gs very early to avoid page faults with stack protector Date: Thu, 1 Feb 2018 13:40:19 +0100 Message-Id: <20180201124019.11693-1-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 | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S index 497cc55a0c16..96f26e026783 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 +37,20 @@ ENTRY(startup_xen) mov %_ASM_SI, xen_start_info mov $init_thread_union+THREAD_SIZE, %_ASM_SP +#ifdef CONFIG_X86_64 + /* 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 +#endif + jmp xen_start_kernel END(startup_xen) __FINIT -- 2.13.6