From patchwork Sun Oct 6 17:20:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 11176577 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2C929112B for ; Sun, 6 Oct 2019 17:49:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0AD7622492 for ; Sun, 6 Oct 2019 17:49:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570384148; bh=9RTI3BxKAQ8c6bSqWTjG3ttwscWdlooxdIEWTE/1ib4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=0T3Owv9ORXupCrcnO9HJANagC647b3tJBdA+7McPvp/52l78MLmgWrXLIBous+P/K RtK0FCULOjqJYyHhFM0FwJXvGlQBJQrTOmF/cXuknUbXrf/sFdm7z+EwT6ueJ4/zpf KOfjh0DJfANe/d9Aq63XZ3r3oCOOwINibbX94c5U= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726984AbfJFRtH (ORCPT ); Sun, 6 Oct 2019 13:49:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:42472 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731368AbfJFRmi (ORCPT ); Sun, 6 Oct 2019 13:42:38 -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 8DDFC20862; Sun, 6 Oct 2019 17:42:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570383757; bh=9RTI3BxKAQ8c6bSqWTjG3ttwscWdlooxdIEWTE/1ib4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WO6xyUeeFi7meBIoj42qowvwDCaUvbGviphovwyxx+lHJKmqou2OFORgW1C7tG3YI sj5sQkMYs0Ch7NtWhjRIfiyt+h8u5x9XqsSpLXRA0UbBXAWPcaOlD322rhaFZ2jfCg +ieq6asuN0iOhTvod/xwAfa2NTJidNBUOFelOl8Y= 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 5.3 082/166] MIPS: Ingenic: Disable broken BTB lookup optimization. Date: Sun, 6 Oct 2019 19:20:48 +0200 Message-Id: <20191006171220.408168864@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191006171212.850660298@linuxfoundation.org> References: <20191006171212.850660298@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@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!");