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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 7F44BC433FF for ; Sat, 10 Aug 2019 20:48:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 55EF0208C3 for ; Sat, 10 Aug 2019 20:48:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727116AbfHJUsv (ORCPT ); Sat, 10 Aug 2019 16:48:51 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:54772 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726776AbfHJUoA (ORCPT ); Sat, 10 Aug 2019 16:44:00 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hwYDV-00053t-KC; Sat, 10 Aug 2019 21:43:57 +0100 Received: from ben by deadeye with local (Exim 4.92) (envelope-from ) id 1hwYDO-0003is-0J; Sat, 10 Aug 2019 21:43:50 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Josh Poimboeuf" , "Thomas Gleixner" Date: Sat, 10 Aug 2019 21:40:07 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 127/157] x86/entry/64: Use JMP instead of JMPQ In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.72-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Josh Poimboeuf commit 64dbc122b20f75183d8822618c24f85144a5a94d upstream. Somehow the swapgs mitigation entry code patch ended up with a JMPQ instruction instead of JMP, where only the short jump is needed. Some assembler versions apparently fail to optimize JMPQ into a two-byte JMP when possible, instead always using a 7-byte JMP with relocation. For some reason that makes the entry code explode with a #GP during boot. Change it back to "JMP" as originally intended. Fixes: 18ec54fdd6d1 ("x86/speculation: Prepare entry code for Spectre v1 swapgs mitigations") Signed-off-by: Josh Poimboeuf Signed-off-by: Thomas Gleixner [bwh: Backported to 3.16: adjust filename, context] Signed-off-by: Ben Hutchings --- arch/x86/kernel/entry_64.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -267,7 +267,7 @@ ENDPROC(native_usergs_sysret64) SWAPGS FENCE_SWAPGS_USER_ENTRY SWITCH_KERNEL_CR3 - jmpq 2f + jmp 2f 1: FENCE_SWAPGS_KERNEL_ENTRY 2: