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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 CB816C3A5A0 for ; Mon, 19 Aug 2019 13:23:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8CEC2085A for ; Mon, 19 Aug 2019 13:23:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727678AbfHSNXt (ORCPT ); Mon, 19 Aug 2019 09:23:49 -0400 Received: from gate.crashing.org ([63.228.1.57]:38433 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727628AbfHSNXr (ORCPT ); Mon, 19 Aug 2019 09:23:47 -0400 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id x7JDNEqX018624; Mon, 19 Aug 2019 08:23:14 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id x7JDND50018616; Mon, 19 Aug 2019 08:23:13 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Mon, 19 Aug 2019 08:23:13 -0500 From: Segher Boessenkool To: Christophe Leroy Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH 3/3] powerpc: use __builtin_trap() in BUG/WARN macros. Message-ID: <20190819132313.GH31406@gate.crashing.org> References: <20510ce03cc9463f1c9e743c1d93b939de501b53.1566219503.git.christophe.leroy@c-s.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20510ce03cc9463f1c9e743c1d93b939de501b53.1566219503.git.christophe.leroy@c-s.fr> User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 19, 2019 at 01:06:31PM +0000, Christophe Leroy wrote: > Note that we keep using an assembly text using "twi 31, 0, 0" for > inconditional traps because GCC drops all code after > __builtin_trap() when the condition is always true at build time. As I said, it can also do this for conditional traps, if it can prove the condition is always true. Can you put the bug table asm *before* the __builtin_trap maybe? That should make it all work fine... If you somehow can tell what machine instruction is that trap, anyway. Segher