From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 19 Dec 2014 09:54:41 +0100 (CET) Received: from mailapp01.imgtec.com ([195.59.15.196]:15278 "EHLO mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S27007783AbaLSIyj6BuL2 (ORCPT ); Fri, 19 Dec 2014 09:54:39 +0100 Received: from KLMAIL01.kl.imgtec.org (unknown [192.168.5.35]) by Websense Email Security Gateway with ESMTPS id EC5573562F7A2; Fri, 19 Dec 2014 08:54:32 +0000 (GMT) Received: from LEMAIL01.le.imgtec.org (192.168.152.62) by KLMAIL01.kl.imgtec.org (192.168.5.35) with Microsoft SMTP Server (TLS) id 14.3.195.1; Fri, 19 Dec 2014 08:54:34 +0000 Received: from [192.168.154.125] (192.168.154.125) by LEMAIL01.le.imgtec.org (192.168.152.62) with Microsoft SMTP Server (TLS) id 14.3.210.2; Fri, 19 Dec 2014 08:54:32 +0000 Message-ID: <5493E7C8.4020302@imgtec.com> Date: Fri, 19 Dec 2014 08:54:32 +0000 From: Markos Chandras User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Joshua Kinard , Subject: Re: [PATCH RFC 47/67] MIPS: kernel: branch: Prevent BEQL emulation for MIPS R6 References: <1418915416-3196-1-git-send-email-markos.chandras@imgtec.com> <1418915416-3196-48-git-send-email-markos.chandras@imgtec.com> <54936992.2070302@gentoo.org> In-Reply-To: <54936992.2070302@gentoo.org> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [192.168.154.125] Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 44830 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: Markos.Chandras@imgtec.com Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips On 12/18/2014 11:56 PM, Joshua Kinard wrote: > On 12/18/2014 10:09, Markos Chandras wrote: >> MIPS R6 removed the BEQL instruction so do not try to emulate it >> if the R2-to-R6 emulator is not present. > > How does this affect code for the old ISAs, MIPS-II to MIPS-IV? I.e., the SGIs > and the R10K CPUs that have to worry about the R10000_LLSC_WAR workaround and > use branch-likely insns? > > --J > it does not affect them (or should not affect them). In case of *any* non-R6 core, the NO_R6EMU macro is false, so all the conditionals here are evaluated to false and the branch emulation will do the right thing. -- markos From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailapp01.imgtec.com ([195.59.15.196]:15278 "EHLO mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S27007783AbaLSIyj6BuL2 (ORCPT ); Fri, 19 Dec 2014 09:54:39 +0100 Message-ID: <5493E7C8.4020302@imgtec.com> Date: Fri, 19 Dec 2014 08:54:32 +0000 From: Markos Chandras MIME-Version: 1.0 Subject: Re: [PATCH RFC 47/67] MIPS: kernel: branch: Prevent BEQL emulation for MIPS R6 References: <1418915416-3196-1-git-send-email-markos.chandras@imgtec.com> <1418915416-3196-48-git-send-email-markos.chandras@imgtec.com> <54936992.2070302@gentoo.org> In-Reply-To: <54936992.2070302@gentoo.org> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-Path: Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-subscribe: List-owner: List-post: List-archive: To: Joshua Kinard , linux-mips@linux-mips.org Message-ID: <20141219085432.tiHHKNQKsdsvoRjFTzGWUHJSl-t_Yxjvn8qNOivbXcw@z> On 12/18/2014 11:56 PM, Joshua Kinard wrote: > On 12/18/2014 10:09, Markos Chandras wrote: >> MIPS R6 removed the BEQL instruction so do not try to emulate it >> if the R2-to-R6 emulator is not present. > > How does this affect code for the old ISAs, MIPS-II to MIPS-IV? I.e., the SGIs > and the R10K CPUs that have to worry about the R10000_LLSC_WAR workaround and > use branch-likely insns? > > --J > it does not affect them (or should not affect them). In case of *any* non-R6 core, the NO_R6EMU macro is false, so all the conditionals here are evaluated to false and the branch emulation will do the right thing. -- markos