From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752353AbeBFJFB (ORCPT ); Tue, 6 Feb 2018 04:05:01 -0500 Received: from isilmar-4.linta.de ([136.243.71.142]:57482 "EHLO isilmar-4.linta.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751835AbeBFJE5 (ORCPT ); Tue, 6 Feb 2018 04:04:57 -0500 Date: Tue, 6 Feb 2018 10:04:55 +0100 From: Dominik Brodowski To: Dan Williams Cc: tglx@linutronix.de, mingo@kernel.org, Andi Kleen , torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, luto@kernel.org Subject: Re: [PATCH v3 2/3] x86/entry: Clear registers for 64bit exceptions/interrupts Message-ID: <20180206090455.GA15925@isilmar-4.linta.de> References: <151787988045.7847.11830748914544718151.stgit@dwillia2-desk3.amr.corp.intel.com> <151787989146.7847.15749181712358213254.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <151787989146.7847.15749181712358213254.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 05, 2018 at 05:18:11PM -0800, Dan Williams wrote: > @@ -1178,6 +1180,7 @@ ENTRY(paranoid_entry) > cld > SAVE_C_REGS 8 > SAVE_EXTRA_REGS 8 > + CLEAR_REGS_NOSPEC > ENCODE_FRAME_POINTER 8 > movl $1, %ebx > movl $MSR_GS_BASE, %ecx > @@ -1185,7 +1188,6 @@ ENTRY(paranoid_entry) > testl %edx, %edx > js 1f /* negative -> in kernel */ > SWAPGS > - xorl %ebx, %ebx Here, %ebx will be filled with $1 (see code snipped above) *after* the call to CLEAR_REGS_NOSPEC. That's what this line has been clearing in the past. So I'm not sure whether this line should be removed. Thanks, Dominik