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 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 77456C7291B for ; Thu, 27 Feb 2020 14:24:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 509EE24656 for ; Thu, 27 Feb 2020 14:24:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389350AbgB0OYq (ORCPT ); Thu, 27 Feb 2020 09:24:46 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:34485 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730366AbgB0OYn (ORCPT ); Thu, 27 Feb 2020 09:24:43 -0500 Received: from p5de0bf0b.dip0.t-ipconnect.de ([93.224.191.11] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1j7K5W-0005uK-CM; Thu, 27 Feb 2020 15:24:30 +0100 Received: by nanos.tec.linutronix.de (Postfix, from userid 1000) id 7766A1040A9; Thu, 27 Feb 2020 15:24:29 +0100 (CET) From: Thomas Gleixner To: Andy Lutomirski Cc: LKML , X86 ML , Steven Rostedt , Brian Gerst , Juergen Gross , Paolo Bonzini , Arnd Bergmann Subject: [patch V2 08/10] x86/entry/32: Remove the 0/-1 distinction from exception entries In-Reply-To: <87y2spb1nr.fsf@nanos.tec.linutronix.de> References: <20200225213636.689276920@linutronix.de> <20200225220216.933457250@linutronix.de> <6dd020cd-e20a-be12-aba7-bfa9e1a94795@kernel.org> <87blpli40i.fsf@nanos.tec.linutronix.de> <87y2spb1nr.fsf@nanos.tec.linutronix.de> Date: Thu, 27 Feb 2020 15:24:29 +0100 Message-ID: <87mu94m7ky.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Nothing cares about the -1 "mark as interrupt" in the errorcode of exception entries. It's only used to fill the error code when a signal is delivered, but this is already inconsistent vs. 64 bit as there all exceptions which do not have an error code set it to 0. So if 32bit applications would care about this, then they would have noticed more than a decade ago. Just use 0 for all excpetions which do not have an errorcode consistently. This does neither break /proc/$PID/syscall because this interface examines the error code / syscall number which is on the stack and that is set to -1 (no syscall) in common_exception unconditionally for all exceptions. The push in the entry stub is just there to fill the hardware error code slot on the stack for consistency of the stack layout. A transient observation of 0 is possible, but that's true for the other exceptions which use 0 already as well and that interface is an unreliable snapshot of dubious correctness anyway. Signed-off-by: Thomas Gleixner Reviewed-by: Alexandre Chartre --- V2: Amend changelog. Rebased on top of tip x86/entry --- arch/x86/entry/entry_32.S | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -1290,7 +1290,7 @@ SYM_CODE_END(simd_coprocessor_error) SYM_CODE_START(device_not_available) ASM_CLAC - pushl $-1 # mark this as an int + pushl $0 pushl $do_device_not_available jmp common_exception SYM_CODE_END(device_not_available) @@ -1531,7 +1531,7 @@ SYM_CODE_START(debug) * Entry from sysenter is now handled in common_exception */ ASM_CLAC - pushl $-1 # mark this as an int + pushl $0 pushl $do_debug jmp common_exception SYM_CODE_END(debug) @@ -1682,7 +1682,7 @@ SYM_CODE_END(nmi) SYM_CODE_START(int3) ASM_CLAC - pushl $-1 # mark this as an int + pushl $0 pushl $do_int3 jmp common_exception SYM_CODE_END(int3)