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 1813EC2D0CF for ; Tue, 24 Dec 2019 14:47:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E82AA206B7 for ; Tue, 24 Dec 2019 14:47:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726171AbfLXOrH (ORCPT ); Tue, 24 Dec 2019 09:47:07 -0500 Received: from gate.crashing.org ([63.228.1.57]:48282 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726128AbfLXOrH (ORCPT ); Tue, 24 Dec 2019 09:47:07 -0500 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id xBOEkNuV031561; Tue, 24 Dec 2019 08:46:23 -0600 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id xBOEkMoQ031560; Tue, 24 Dec 2019 08:46:22 -0600 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Tue, 24 Dec 2019 08:46:21 -0600 From: Segher Boessenkool To: Andy Lutomirski Cc: christophe leroy , Arnd Bergmann , X86 ML , LKML , "open list:MIPS" , Paul Mackerras , Andy Lutomirski , Thomas Gleixner , Vincenzo Frascino , linuxppc-dev , linux-arm-kernel Subject: Re: [RFC PATCH v2 04/10] lib: vdso: get pointer to vdso data from the arch Message-ID: <20191224144621.GG4505@gate.crashing.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.4.2.3i Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On Tue, Dec 24, 2019 at 08:15:11PM +0800, Andy Lutomirski wrote: > Does power have PC-relative data access? If so, I wonder if the code can be arranged so that even the array accesses don’t require computing an absolute address at any point. Not before ISA 3.0 (that is Power9). The bcl/mflr dance isn't *that* expensive, if you use it sparingly. Segher 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 53041C2D0CF for ; Tue, 24 Dec 2019 14:48:45 +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 C4559206B7 for ; Tue, 24 Dec 2019 14:48:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C4559206B7 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 lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 47hzcV0zJpzDqNR for ; Wed, 25 Dec 2019 01:48:42 +1100 (AEDT) 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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 47hzZS1KC2zDqJj for ; Wed, 25 Dec 2019 01:46:53 +1100 (AEDT) Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id xBOEkNuV031561; Tue, 24 Dec 2019 08:46:23 -0600 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id xBOEkMoQ031560; Tue, 24 Dec 2019 08:46:22 -0600 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Tue, 24 Dec 2019 08:46:21 -0600 From: Segher Boessenkool To: Andy Lutomirski Subject: Re: [RFC PATCH v2 04/10] lib: vdso: get pointer to vdso data from the arch Message-ID: <20191224144621.GG4505@gate.crashing.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: 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: Arnd Bergmann , X86 ML , LKML , "open list:MIPS" , Paul Mackerras , Andy Lutomirski , Thomas Gleixner , Vincenzo Frascino , linuxppc-dev , linux-arm-kernel Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, Dec 24, 2019 at 08:15:11PM +0800, Andy Lutomirski wrote: > Does power have PC-relative data access? If so, I wonder if the code can be arranged so that even the array accesses don’t require computing an absolute address at any point. Not before ISA 3.0 (that is Power9). The bcl/mflr dance isn't *that* expensive, if you use it sparingly. Segher 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=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 46063C2D0CF for ; Tue, 24 Dec 2019 14:46:51 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 1070820706 for ; Tue, 24 Dec 2019 14:46:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="jm7N5WNl" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1070820706 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Mime-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=jPFzliUMXQg3tI9eTuAgMSBiH1bJCPetak6nUL6w538=; b=jm7N5WNl1uklXe pwe5vg9L76EJ1OV+GkgBGq3mzpb5q0NgLupm3b0XJGFlOpPgcBZ+yLbGGdUkTUYOzwOHU7dyMPidY gs5Vnd2WtHrqe8xj81/Pf4EFxgU4Iy090DqAykU4Dbdjp4f2BBYFrH/JLdG/HWATlKKymyi66SDRV 7+hF54v+GaDV3kg5XRoKtGn2Izwvh2EJnMjtSRgM9XFulu6GnVIsuHf6CvwJRpXDaNPqw1tCzeSji 0V0ye8Dmb+oadxO/pt37laXb3RpfMkCLbyVqOEQvL6OMY54MdHTJ7Tj4eV0NIdC5G3epapqSd4WRc yRB+6/BcJHypMviHK/2g==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1ijlSU-0007v5-LU; Tue, 24 Dec 2019 14:46:50 +0000 Received: from gate.crashing.org ([63.228.1.57]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1ijlSR-0007uj-Bc for linux-arm-kernel@lists.infradead.org; Tue, 24 Dec 2019 14:46:48 +0000 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id xBOEkNuV031561; Tue, 24 Dec 2019 08:46:23 -0600 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id xBOEkMoQ031560; Tue, 24 Dec 2019 08:46:22 -0600 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Tue, 24 Dec 2019 08:46:21 -0600 From: Segher Boessenkool To: Andy Lutomirski Subject: Re: [RFC PATCH v2 04/10] lib: vdso: get pointer to vdso data from the arch Message-ID: <20191224144621.GG4505@gate.crashing.org> References: Mime-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191224_064647_543648_EDF4A7A2 X-CRM114-Status: UNSURE ( 5.81 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: christophe leroy , Arnd Bergmann , X86 ML , LKML , "open list:MIPS" , Paul Mackerras , Andy Lutomirski , Thomas Gleixner , Vincenzo Frascino , linuxppc-dev , linux-arm-kernel Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org T24gVHVlLCBEZWMgMjQsIDIwMTkgYXQgMDg6MTU6MTFQTSArMDgwMCwgQW5keSBMdXRvbWlyc2tp IHdyb3RlOgo+IERvZXMgcG93ZXIgaGF2ZSBQQy1yZWxhdGl2ZSBkYXRhIGFjY2Vzcz8gIElmIHNv LCBJIHdvbmRlciBpZiB0aGUgY29kZSBjYW4gYmUgYXJyYW5nZWQgc28gdGhhdCBldmVuIHRoZSBh cnJheSBhY2Nlc3NlcyBkb27igJl0IHJlcXVpcmUgY29tcHV0aW5nIGFuIGFic29sdXRlIGFkZHJl c3MgYXQgYW55IHBvaW50LgoKTm90IGJlZm9yZSBJU0EgMy4wICh0aGF0IGlzIFBvd2VyOSkuCgpU aGUgYmNsL21mbHIgZGFuY2UgaXNuJ3QgKnRoYXQqIGV4cGVuc2l2ZSwgaWYgeW91IHVzZSBpdCBz cGFyaW5nbHkuCgoKU2VnaGVyCgpfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fXwpsaW51eC1hcm0ta2VybmVsIG1haWxpbmcgbGlzdApsaW51eC1hcm0ta2VybmVs QGxpc3RzLmluZnJhZGVhZC5vcmcKaHR0cDovL2xpc3RzLmluZnJhZGVhZC5vcmcvbWFpbG1hbi9s aXN0aW5mby9saW51eC1hcm0ta2VybmVsCg==