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=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 8D3D7C43381 for ; Wed, 10 Feb 2021 02:28:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6DB8164E32 for ; Wed, 10 Feb 2021 02:28:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235465AbhBJC2L (ORCPT ); Tue, 9 Feb 2021 21:28:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49822 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235160AbhBJB61 (ORCPT ); Tue, 9 Feb 2021 20:58:27 -0500 Received: from mail-pj1-x102b.google.com (mail-pj1-x102b.google.com [IPv6:2607:f8b0:4864:20::102b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3F899C061574 for ; Tue, 9 Feb 2021 17:57:47 -0800 (PST) Received: by mail-pj1-x102b.google.com with SMTP id d2so246241pjs.4 for ; Tue, 09 Feb 2021 17:57:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:subject:to:cc:references:in-reply-to:mime-version :message-id:content-transfer-encoding; bh=oLW+n5w0pghmkNj2ep8nCPeAU0s26nQfvVVpmEbyunM=; b=lOPNp9fFMtEacEN782fXGeE95Kdh37rGdiUidWXHnY98Nrevlcw+Efy/0o211FTwMz 1/kFVmyhObSCsMwK6dLGptAylcMJt4OpAvCw4NY8eYpiVQtloRdNjN3G5Qq0S7a4qOny vVoK+GoBEkiZm3n7N5h1ts/Kqn+0ExSl9hpvJ5EIIZzW8McWqME5U8Yf0FEMs+v7YvDB O8N153T+UN6Nuz80eM6/cXYdu2S1YbU2cmkczrjRlPjt8kIIDMEnWYIyqvn/EWWYTkCo S2G0EQzENA+dvh7xLhfgUDDFj5HddiRjZPMsIvn63nJgsJjGDn+T4QNlMlnKfyILkeMA kPcw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:subject:to:cc:references:in-reply-to :mime-version:message-id:content-transfer-encoding; bh=oLW+n5w0pghmkNj2ep8nCPeAU0s26nQfvVVpmEbyunM=; b=NIqzGTUm8DWrCPxYHiQkmWKJ4I7Mu1bg3yZZCniLJywK7JIMZ+x/KXDE3HaBuTARwd ZdWJt1V5gaRJf8rqgKB3wVa4DkdGTJmpOliVoq6VS4H7I+JiWEwkZnhPPxmQYBScIJGg BEBx83z9PdacGJrj8SrGfTStVLVwtqHo1/CWWjEfV60sVBMsSbfjU54dIDlD4xAjF6Mw hnw+jIG+rA4sdLmRh7Kn//ANobOYVj/z1Tr2vEnUKDlpz8sxDkGBsNT/SjrzxR9+Pdji Q7dkcH7dURmNY7kE4se7vOfJXaiuZ9qjnvTMOiK2LDJAsKNlfHcg3ijQDdQd7EeK58Fa lYkQ== X-Gm-Message-State: AOAM533ZvZFQ9O88MiXliNOIyBoanbYJVAATWvHjeD1IJcuJc3y3kcOk Ad016nevabr1lHbs9i/dgKw= X-Google-Smtp-Source: ABdhPJzN+0Dc764xEdE636nOl2URQeFOcnQuIGS2ucB0THifofkFPCwdFUff0eCkTGWMDmfv5U+lWA== X-Received: by 2002:a17:902:a5cb:b029:de:cd0b:1424 with SMTP id t11-20020a170902a5cbb02900decd0b1424mr647751plq.63.1612922266884; Tue, 09 Feb 2021 17:57:46 -0800 (PST) Received: from localhost (14-201-150-91.tpgi.com.au. [14.201.150.91]) by smtp.gmail.com with ESMTPSA id b14sm185543pfi.74.2021.02.09.17.57.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Feb 2021 17:57:45 -0800 (PST) Date: Wed, 10 Feb 2021 11:57:40 +1000 From: Nicholas Piggin Subject: Re: [PATCH v5 18/22] powerpc/syscall: Remove FULL_REGS verification in system_call_exception To: Benjamin Herrenschmidt , Christophe Leroy , Michael Ellerman , msuchanek@suse.de, Paul Mackerras Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org References: <6bef4d9ba0cba50160d13e344ee4627ebdf801dc.1612796617.git.christophe.leroy@csgroup.eu> <1612836023.l122pe2n2b.astroid@bobo.none> In-Reply-To: MIME-Version: 1.0 Message-Id: <1612922197.2b51jxzeqs.astroid@bobo.none> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Excerpts from Christophe Leroy's message of February 10, 2021 12:31 am: >=20 >=20 > Le 09/02/2021 =C3=A0 03:02, Nicholas Piggin a =C3=A9crit=C2=A0: >> Excerpts from Christophe Leroy's message of February 9, 2021 1:10 am: >>> For book3s/64, FULL_REGS() is 'true' at all time, so the test voids. >>> For others, non volatile registers are saved inconditionally. >>> >>> So the verification is pointless. >>> >>> Should one fail to do it, it would anyway be caught by the >>> CHECK_FULL_REGS() in copy_thread() as we have removed the >>> special versions ppc_fork() and friends. >>> >>> null_syscall benchmark reduction 4 cycles (332 =3D> 328 cycles) >>=20 >> I wonder if we rather make a CONFIG option for a bunch of these simpler >> debug checks here (and also in interrupt exit, wrappers, etc) rather >> than remove them entirely. >=20 > We can drop this patch if you prefer. Anyway, like book3s/64, once ppc32 = also do interrupt=20 > entry/exit in C, FULL_REGS() will already return true. Sure let's do that. Thanks, Nick