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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 488FEC433F5 for ; Wed, 18 May 2022 07:44:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232318AbiERHn5 (ORCPT ); Wed, 18 May 2022 03:43:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232373AbiERHn4 (ORCPT ); Wed, 18 May 2022 03:43:56 -0400 X-Greylist: delayed 1801 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Wed, 18 May 2022 00:43:52 PDT Received: from outbound5i.eu.mailhop.org (outbound5i.eu.mailhop.org [35.156.234.212]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6977027FF9 for ; Wed, 18 May 2022 00:43:50 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1652857063; cv=none; d=outbound.mailhop.org; s=arc-outbound20181012; b=bRd8+Q46NgbENUyIchSjDUSeu2fpzdS4QFbCk3vZ6xZAERIsNy/gaMfx0PIl9XEav8rv6p8BAudUT rkfVYHRYAbn4MSeDjs3Oww5P0O5iJb5/NiJH/KjahLHDPAHQ3Ef+Azg/zyRxZ5iEMysWxzgrCvXqKb Usd9lrdm4khDKx6u1S3CpPHDwAw7ogvaUdXv81mEv7kZ80G7JvCgujIg0doSMAAeTw1U3mwG2xFUSa ElbzY9lMWlke9jToHpkMzQvgiRkeYS1iRFzsbhyPTyjcVI3mZLNC1fJtTDSb6PHWXWU/6vKvpJNINP ynNEv5NEZAciq2QxlHxGJza8SORv0qw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=outbound.mailhop.org; s=arc-outbound20181012; h=content-type:mime-version:message-id:in-reply-to:date:references:subject:cc: to:from:dkim-signature:dkim-signature:from; bh=N/AKMdeBtgz5NQpWuWjsa101CdoV6t7LzXY8BMZ3fMw=; b=DoX9rQ7Nj2mhTjJsXWmcGMdx+Vq2rrWvcCdZXZaIhZauBSLZmxmg7TgKhJM/tLoRiEkwR4JS07tr2 2wU/bUdDbcebSeA2vcn9fhnACg8xIpUXYULGgiSqMSkuzd/+eJSnqrDbk14Iu/HHryRafDZY5CXYIo oJA1GEM3vfzGU3vy92xaGx2tkSL5Ff2nmrZ/1kRdAffYK2OF6XVnikoGmEUUjcwPOaciT8CppC4BTW tQ6PKOcT0tN9mlD83r3wAgJQ/mvPLmKQnr3hZsjFziaNrCpM0yThviwXj+dtL2Te1O4SR3MVm/7U5y q/OAptRsCodZ2rbZKa+cIOQ2WKEJ9DQ== ARC-Authentication-Results: i=1; outbound2.eu.mailhop.org; spf=pass smtp.mailfrom=stackframe.org smtp.remote-ip=130.180.31.158; dmarc=none header.from=stackframe.org; arc=none header.oldest-pass=0; DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=stackframe.org; s=duo-1634547266507-560c42ae; h=content-type:mime-version:message-id:in-reply-to:date:references:subject:cc: to:from:from; bh=N/AKMdeBtgz5NQpWuWjsa101CdoV6t7LzXY8BMZ3fMw=; b=pjWBNuhmQMkaPfH2nDM9FJ6nIieBw9uWsU38qgsoGkvtQUpocZhvYWmaeHghKkHaVJuRfOvb97ibm bb5zWoWcAnK3HNzmJaune5ej2NjvARBt4pjOCu1aBdN6hPEIInkXlW+nSLGzAfzllvNqBm9w+5w/F5 02TPwIepknJGPPD4= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=outbound.mailhop.org; s=dkim-high; h=content-type:mime-version:message-id:in-reply-to:date:references:subject:cc: to:from:from; bh=N/AKMdeBtgz5NQpWuWjsa101CdoV6t7LzXY8BMZ3fMw=; b=C5JWoV/XCME7SRTZM9uEBf0N8H9VvOudCR3f6adjtyZyB8EP3j/i33zSJ9K/7Z9dHp0ug/xcnEbHN 3bJ0/QVNNAsmX/FeUzQIPLPt+mydsAjWV3hUhcdjSOPGYanqiXnfjSg9fI7onzcJUjtBCWoOumojWp FrzdXoHwRzkIseoDPgWH93JYQKrde+/2AnlAy532NLH+Cm+3kw0fBPWltATu7GsutoVVVwukzvksxw Tonnb93MXbXL6MAAbNR9b8WY0CnGmHsW8vNbZvqsQfLMbur6RR0wvjpIszCMirwXHJV/2gSEZL+peD KekrsPMYXcG16hOlfTB5MAF6wVAARpg== X-Originating-IP: 130.180.31.158 X-MHO-RoutePath: dG9ta2lzdG5lcm51 X-MHO-User: cd84c994-d677-11ec-bc05-4b4748ac966b X-Report-Abuse-To: https://support.duocircle.com/support/solutions/articles/5000540958-duocircle-standard-smtp-abuse-information X-Mail-Handler: DuoCircle Outbound SMTP Received: from mail.duncanthrax.net (ip-130-180-031-158.um40.pools.vodafone-ip.de [130.180.31.158]) by outbound2.eu.mailhop.org (Halon) with ESMTPSA id cd84c994-d677-11ec-bc05-4b4748ac966b; Wed, 18 May 2022 06:57:40 +0000 (UTC) Received: from ip-046-005-169-013.um12.pools.vodafone-ip.de ([46.5.169.13] helo=x1.stackframe.org.stackframe.org) by mail.duncanthrax.net with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1nrDct-0000CC-IW; Wed, 18 May 2022 08:57:43 +0200 From: Sven Schnelle To: Helge Deller Cc: linux-parisc@vger.kernel.org, James Bottomley , John David Anglin Subject: Re: [PATCH] parisc: Prevent using same register as soure and target in extru/shr References: <8b5c308a-f3ea-e07f-053a-ad086ce75c43@gmx.de> Date: Wed, 18 May 2022 08:57:36 +0200 In-Reply-To: <8b5c308a-f3ea-e07f-053a-ad086ce75c43@gmx.de> (Helge Deller's message of "Tue, 17 May 2022 14:54:44 +0200") Message-ID: <87zgjfl44f.fsf@x1.stackframe.org> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org Helge Deller writes: > On 5/17/22 14:49, Helge Deller wrote: >> In 2004 Randolph added the shr() assembly macro and noted that the >> source and target register could not be the same. >> >> I did not find any confindence in the docs for this restriction. Maybe >> it's related that on PA2.0 the upper bits may be clobbered? > > Looking at the generated kernel code from C-files, I'll find all over usages of > extru source, x,y, target > where source and target are the same register. > So, at least for 32-bit this restriction can't be true. I did a quick objdump on the 64 bit HP-UX kernel and that one also uses extrd/extrw where target and source are the same register. So i don't think that restriction is true.