From patchwork Tue Feb 11 13:52:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joerg Roedel X-Patchwork-Id: 11375623 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A14951395 for ; Tue, 11 Feb 2020 13:57:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A5E22467C for ; Tue, 11 Feb 2020 13:57:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729510AbgBKN5W (ORCPT ); Tue, 11 Feb 2020 08:57:22 -0500 Received: from 8bytes.org ([81.169.241.247]:51838 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729516AbgBKNxX (ORCPT ); Tue, 11 Feb 2020 08:53:23 -0500 Received: by theia.8bytes.org (Postfix, from userid 1000) id 2ADFDE3A; Tue, 11 Feb 2020 14:53:12 +0100 (CET) From: Joerg Roedel To: x86@kernel.org Cc: hpa@zytor.com, Andy Lutomirski , Dave Hansen , Peter Zijlstra , Thomas Hellstrom , Jiri Slaby , Dan Williams , Tom Lendacky , Juergen Gross , Kees Cook , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, Joerg Roedel , Joerg Roedel Subject: [PATCH 28/62] x86/head/64: Switch to initial stack earlier Date: Tue, 11 Feb 2020 14:52:22 +0100 Message-Id: <20200211135256.24617-29-joro@8bytes.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200211135256.24617-1-joro@8bytes.org> References: <20200211135256.24617-1-joro@8bytes.org> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Joerg Roedel Make sure there is a stack once the kernel runs from virual addresses. At this stage any secondary CPU which boots will have lost its stack because the kernel switched to a new page-table which does not map the real-mode stack anymore. This is also needed for handling early #VC exceptions caused by instructions like CPUID. Signed-off-by: Joerg Roedel --- arch/x86/kernel/head_64.S | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 36f2f30ad200..eefd6838b895 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -188,6 +188,12 @@ SYM_CODE_START(secondary_startup_64) movl initial_gs+4(%rip),%edx wrmsr + /* + * Setup a boot time stack - Any secondary CPU will have lost its stack + * by now because the cr3-switch above unmaps the real-mode stack + */ + movq initial_stack(%rip), %rsp + /* Check if nx is implemented */ movl $0x80000001, %eax cpuid @@ -208,9 +214,6 @@ SYM_CODE_START(secondary_startup_64) /* Make changes effective */ movq %rax, %cr0 - /* Setup a boot time stack */ - movq initial_stack(%rip), %rsp - /* zero EFLAGS after setting rsp */ pushq $0 popfq