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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 5EC04C10F14 for ; Sun, 6 Oct 2019 17:38:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 380FE2173B for ; Sun, 6 Oct 2019 17:38:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570383523; bh=9RTI3BxKAQ8c6bSqWTjG3ttwscWdlooxdIEWTE/1ib4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=w6fK5JRJdm2CgOZ5gjs1+7Q3znn+hH++i7GjLlt99YB14VUtmkbpxGIjfxMb2sr81 TiJHV+lcrbOfhOAv4tx6X2O+Vsmn49K5ayjqnRpwmvIdbcCBOF+14uwB74rxmX8EBk Zj4sUhm1wi43LFclJSDsfuO0+hpgpjpVu6bo+qnM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730659AbfJFRim (ORCPT ); Sun, 6 Oct 2019 13:38:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:37920 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730643AbfJFRih (ORCPT ); Sun, 6 Oct 2019 13:38:37 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B277B2087E; Sun, 6 Oct 2019 17:38:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570383516; bh=9RTI3BxKAQ8c6bSqWTjG3ttwscWdlooxdIEWTE/1ib4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IIxHuEHsaN5HOvw/8BoAF1YC5JnxgQaZv/DQTADRex9Z/ztE7LVY6+/i3bELKFuF/ 7zzPh3NMzHokUTAMkkhnMyvWWit/mWqpEYEwdEv/w9quGiE7FMGGsr8yDzeImPzynH xmNGcl+68BcmSYZiSA6Z8+7pcq+g1fbrjcGhdgk0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zhou Yanjie , Paul Burton , linux-mips@vger.kernel.org, ralf@linux-mips.org, paul@crapouillou.net, jhogan@kernel.org, malat@debian.org, tglx@linutronix.de, allison@lohutok.net, syq@debian.org, chenhc@lemote.com, jiaxun.yang@flygoat.com, Sasha Levin Subject: [PATCH 5.2 090/137] MIPS: Ingenic: Disable broken BTB lookup optimization. Date: Sun, 6 Oct 2019 19:21:14 +0200 Message-Id: <20191006171216.329875861@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191006171209.403038733@linuxfoundation.org> References: <20191006171209.403038733@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Zhou Yanjie [ Upstream commit 053951dda71ecb4b554a2cdbe26f5f6f9bee9dd2 ] In order to further reduce power consumption, the XBurst core by default attempts to avoid branch target buffer lookups by detecting & special casing loops. This feature will cause BogoMIPS and lpj calculate in error. Set cp0 config7 bit 4 to disable this feature. Signed-off-by: Zhou Yanjie Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: ralf@linux-mips.org Cc: paul@crapouillou.net Cc: jhogan@kernel.org Cc: malat@debian.org Cc: gregkh@linuxfoundation.org Cc: tglx@linutronix.de Cc: allison@lohutok.net Cc: syq@debian.org Cc: chenhc@lemote.com Cc: jiaxun.yang@flygoat.com Signed-off-by: Sasha Levin --- arch/mips/include/asm/mipsregs.h | 4 ++++ arch/mips/kernel/cpu-probe.c | 7 +++++++ 2 files changed, 11 insertions(+) diff --git a/arch/mips/include/asm/mipsregs.h b/arch/mips/include/asm/mipsregs.h index 1e6966e8527e9..bdbdc19a2b8f8 100644 --- a/arch/mips/include/asm/mipsregs.h +++ b/arch/mips/include/asm/mipsregs.h @@ -689,6 +689,9 @@ #define MIPS_CONF7_IAR (_ULCAST_(1) << 10) #define MIPS_CONF7_AR (_ULCAST_(1) << 16) +/* Ingenic Config7 bits */ +#define MIPS_CONF7_BTB_LOOP_EN (_ULCAST_(1) << 4) + /* Config7 Bits specific to MIPS Technologies. */ /* Performance counters implemented Per TC */ @@ -2813,6 +2816,7 @@ __BUILD_SET_C0(status) __BUILD_SET_C0(cause) __BUILD_SET_C0(config) __BUILD_SET_C0(config5) +__BUILD_SET_C0(config7) __BUILD_SET_C0(intcontrol) __BUILD_SET_C0(intctl) __BUILD_SET_C0(srsmap) diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c index 9635c1db3ae6a..e654ffc1c8a0d 100644 --- a/arch/mips/kernel/cpu-probe.c +++ b/arch/mips/kernel/cpu-probe.c @@ -1964,6 +1964,13 @@ static inline void cpu_probe_ingenic(struct cpuinfo_mips *c, unsigned int cpu) c->cputype = CPU_JZRISC; c->writecombine = _CACHE_UNCACHED_ACCELERATED; __cpu_name[cpu] = "Ingenic JZRISC"; + /* + * The XBurst core by default attempts to avoid branch target + * buffer lookups by detecting & special casing loops. This + * feature will cause BogoMIPS and lpj calculate in error. + * Set cp0 config7 bit 4 to disable this feature. + */ + set_c0_config7(MIPS_CONF7_BTB_LOOP_EN); break; default: panic("Unknown Ingenic Processor ID!"); -- 2.20.1