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 71DFDC47254 for ; Tue, 5 May 2020 22:12:58 +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 2C429206B8 for ; Tue, 5 May 2020 22:12:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2C429206B8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org 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 49Gv9g6tQmzDqQ4 for ; Wed, 6 May 2020 08:12:55 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=permerror (SPF Permanent Error: Unknown mechanism found: ip:192.40.192.88/32) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=segher@kernel.crashing.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by lists.ozlabs.org (Postfix) with ESMTP id 49Gv7t4NmhzDqPN for ; Wed, 6 May 2020 08:11:22 +1000 (AEST) Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 045MBJ7B009822; Tue, 5 May 2020 17:11:19 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 045MBJNJ009821; Tue, 5 May 2020 17:11:19 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Tue, 5 May 2020 17:11:19 -0500 From: Segher Boessenkool To: Nicholas Piggin Subject: Re: [RFC PATCH 2/2] powerpc/64s: system call support for scv/rfscv instructions Message-ID: <20200505221119.GQ31009@gate.crashing.org> References: <20200430040202.1735506-1-npiggin@gmail.com> <20200430040202.1735506-3-npiggin@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200430040202.1735506-3-npiggin@gmail.com> User-Agent: Mutt/1.4.2.3i 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: , Cc: linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hi! On Thu, Apr 30, 2020 at 02:02:02PM +1000, Nicholas Piggin wrote: > Add support for the scv instruction on POWER9 and later CPUs. Looks good to me in general :-) > For now this implements the zeroth scv vector 'scv 0', as identical > to 'sc' system calls, with the exception that lr is not preserved, and > it is 64-bit only. There may yet be changes made to this ABI, so it's > for testing only. What does it do with SF=0? I don't see how it is obviously not a security hole currently (but I didn't look too closely). Segher