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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 C151CC46464 for ; Sat, 11 Aug 2018 02:46:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 78DD122430 for ; Sat, 11 Aug 2018 02:46:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 78DD122430 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ZenIV.linux.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727426AbeHKFS3 (ORCPT ); Sat, 11 Aug 2018 01:18:29 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:60734 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727093AbeHKFS3 (ORCPT ); Sat, 11 Aug 2018 01:18:29 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.87 #1 (Red Hat Linux)) id 1foJub-0000QB-UZ; Sat, 11 Aug 2018 02:45:53 +0000 Date: Sat, 11 Aug 2018 03:45:53 +0100 From: Al Viro To: Richard Henderson Cc: Firoz Khan , linux-alpha@vger.kernel.org, ink@jurassic.park.msu.ru, mattst88@gmail.com, y2038@lists.linaro.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, arnd@arndb.de, deepa.kernel@gmail.com Subject: Re: [PATCH 3/6] alpha: Unify the not-implemented system call entry name Message-ID: <20180811024553.GF6515@ZenIV.linux.org.uk> References: <1531736638-15294-1-git-send-email-firoz.khan@linaro.org> <1531736638-15294-4-git-send-email-firoz.khan@linaro.org> <20180811000455.GC6515@ZenIV.linux.org.uk> <98937991-cefa-b7f3-11c3-12727b3159b1@twiddle.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <98937991-cefa-b7f3-11c3-12727b3159b1@twiddle.net> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 10, 2018 at 07:31:55PM -0700, Richard Henderson wrote: > > +++ b/arch/alpha/kernel/entry.S > > @@ -473,7 +473,7 @@ entSys: > > bne $3, strace > > beq $4, 1f > > ldq $27, 0($5) > > -1: jsr $26, ($27), alpha_ni_syscall > > +1: jsr $26, ($27), sys_ni_syscall > > ldgp $gp, 0($26) > > blt $0, $syscall_error /* the call failed */ > > stq $0, 0($sp) > > Once upon a time I had a patch to make the hint > be sys_gettimeofday, as the most common syscall. > Dunno what happened to that. Might as well... ptraced case has it, non-ptraced doesn't. BTW, seeing that it's your code - why was unop used in alpha_ni_syscall? I don't remember the rules re pipeline stalls; is it that some earlier variants prefer unop to nop in such places? It's not that microoptimizing that one makes any difference, but just out of curiosity - would something like lda $0, -ENOSYS stq $sp, 0($sp) /* sp != 0 */ ret do just as well there?