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=-0.6 required=3.0 tests=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 6E0AFC3A5A3 for ; Tue, 27 Aug 2019 10:44:04 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D500F206BB for ; Tue, 27 Aug 2019 10:44:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="nalX0/t8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D500F206BB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 46Hlq44dchzDqCc for ; Tue, 27 Aug 2019 20:44:00 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=gmail.com (client-ip=2607:f8b0:4864:20::443; helo=mail-pf1-x443.google.com; envelope-from=npiggin@gmail.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="nalX0/t8"; dkim-atps=neutral Received: from mail-pf1-x443.google.com (mail-pf1-x443.google.com [IPv6:2607:f8b0:4864:20::443]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 46Hlmp4LXlzDq9Q for ; Tue, 27 Aug 2019 20:42:01 +1000 (AEST) Received: by mail-pf1-x443.google.com with SMTP id i30so13856080pfk.9 for ; Tue, 27 Aug 2019 03:42:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:subject:to:references:in-reply-to:mime-version:user-agent :message-id:content-transfer-encoding; bh=VWiw7Lb+HCIlUzBtXkd7EsakEG5gSdvS6oqUctzBf+w=; b=nalX0/t8kSqnxcBx6R7ohuy9dntZjBEg76RjxynHaNjZyXU6xh/XCG1LR4luU71iNp c74iDLUO/4b5yXiFK7/A229hriXoEK3ATMsziuOKRMw6tMbgtZqqe0lvxGJBgNNL9v0X FyffkXfEyhyO7P/+ge0vy/9vVjVRgzLeUiK2m+3unR7uwc1JQWATH7kXGDrNsZmUkj/e LIHSQjxR/1GpEswWx2jVqOlXXqN5e80WSsyJc/iixZ7JNmrDZqZ0XZ26do5r/xUl4x6z QSmSsXUu0bS4LsqJtSpZzxnOf3Q11EhLab9mKUCXQ+KXSNmSvFALRmDRI0s8Bz3O47h7 Ii4Q== 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:references:in-reply-to :mime-version:user-agent:message-id:content-transfer-encoding; bh=VWiw7Lb+HCIlUzBtXkd7EsakEG5gSdvS6oqUctzBf+w=; b=LCtwEMQ7o/AgGbNrg7yl7ISEv2wZJIVu4dOb80K+LgXSuClJ06hmmJMNEU6M6qDI0E 6DZa+yHWYlOWqLuZmyZY4fc4ibD2g+5AG5j9ZHDJBWlj/UIkbIi7RHS2SH3goCQBn1WI pEYunwkiBm/WwCcX4bXiXu0uYxZODRxDKbqYH5weRdHA2Y3X91orQ9o0B8LRohF7xQTi GZEW4Ng+Mn+0dItoyyIKASZnBVMZLOT1x+fKx5w2OPDATBBPetiDjY3l5COs0UsS6o43 b4vSWAVzh7lIYrQA3fTRx5rWOjeXr4XZplPgGdd4oct1eLdLhe3uaygLKA2ijot8XqvU 27GA== X-Gm-Message-State: APjAAAVi3cjc3sinqPSbRvmFpl897MxPpm7xQZneSdiV/1kdI32GbxOe ZxpWJwom8CY8XQDOW7IqmCk= X-Google-Smtp-Source: APXvYqxhrJGK6PClSFOs28AWXATmci6ohSHZWYtL/z2MK5dWtkDoDgmD6f5aeIL5lq7hz5EYVvfzjQ== X-Received: by 2002:a65:4505:: with SMTP id n5mr18502823pgq.301.1566902519729; Tue, 27 Aug 2019 03:41:59 -0700 (PDT) Received: from localhost (14-202-91-55.tpgi.com.au. [14.202.91.55]) by smtp.gmail.com with ESMTPSA id r4sm16283122pfl.127.2019.08.27.03.41.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Aug 2019 03:41:59 -0700 (PDT) Date: Tue, 27 Aug 2019 20:41:20 +1000 From: Nicholas Piggin Subject: Re: [PATCH 2/4] powerpc/64: remove support for kernel-mode syscalls To: Christophe Leroy , linuxppc-dev@lists.ozlabs.org References: <20190827033010.28090-1-npiggin@gmail.com> <20190827033010.28090-3-npiggin@gmail.com> <4bcfa6ed-07f7-f162-664f-134b40124dda@c-s.fr> <1566900842.ttf5qhpflv.astroid@bobo.none> In-Reply-To: <1566900842.ttf5qhpflv.astroid@bobo.none> MIME-Version: 1.0 User-Agent: astroid/0.15.0 (https://github.com/astroidmail/astroid) Message-Id: <1566902428.f4rgy4icjs.astroid@bobo.none> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Nicholas Piggin's on August 27, 2019 8:20 pm: > Christophe Leroy's on August 27, 2019 4:13 pm: >>=20 >>=20 >> Le 27/08/2019 =C3=A0 05:30, Nicholas Piggin a =C3=A9crit=C2=A0: >>> There is support for the kernel to execute the 'sc 0' instruction and >>> make a system call to itself. This is a relic that is unused in the >>> tree, therefore untested. It's also highly questionable for modules to >>> be doing this. >>=20 >> I like it. >>=20 >> I dropped support for that in PPC32 when I added fast-path syscalls. >=20 > Good, then we'll match again. >=20 >>> - beq 2f /* if from kernel mode */ >>> #ifdef CONFIG_PPC_FSL_BOOK3E >>> START_BTB_FLUSH_SECTION >>> BTB_FLUSH(r10) >>> END_BTB_FLUSH_SECTION >>> #endif >>> ACCOUNT_CPU_USER_ENTRY(r13, r10, r11) >>> -2: std r2,GPR2(r1) >=20 > Btw. there is a hunk which restores this optimisation but it leaked > into a later patch, I'll move it back here. I'm wrong. Now I look at it again, the hunk should be removed completely of course. Thanks, Nick =