From nobody Sun Sep 22 06:25:43 2024 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 155C0C433FE for ; Wed, 27 Apr 2022 16:17:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242593AbiD0QUV (ORCPT ); Wed, 27 Apr 2022 12:20:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49762 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242589AbiD0QR1 (ORCPT ); Wed, 27 Apr 2022 12:17:27 -0400 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8E2D137A28; Wed, 27 Apr 2022 09:13:59 -0700 (PDT) X-UUID: 23e1612f64424da8a3669018aae4f734-20220428 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.4,REQID:447c4577-8a9b-4e91-af1e-669a4fd39e05,OB:0,LO B:0,IP:0,URL:0,TC:0,Content:-20,EDM:0,RT:0,SF:0,FILE:0,RULE:Release_Ham,AC TION:release,TS:-20 X-CID-META: VersionHash:faefae9,CLOUDID:143eec2e-6199-437e-8ab4-9920b4bc5b76,C OID:IGNORED,Recheck:0,SF:nil,TC:nil,Content:0,EDM:-3,File:nil,QS:0,BEC:nil X-UUID: 23e1612f64424da8a3669018aae4f734-20220428 Received: from mtkexhb01.mediatek.inc [(172.21.101.102)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 1925754874; Thu, 28 Apr 2022 00:13:54 +0800 Received: from mtkcas11.mediatek.inc (172.21.101.40) by mtkmbs11n2.mediatek.inc (172.21.101.187) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.792.3; Thu, 28 Apr 2022 00:13:53 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkcas11.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Thu, 28 Apr 2022 00:13:53 +0800 From: Lecopzer Chen To: , CC: , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v4 5/6] arm64: add hw_nmi_get_sample_period for preparation of lockup detector Date: Thu, 28 Apr 2022 00:13:39 +0800 Message-ID: <20220427161340.8518-6-lecopzer.chen@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20220427161340.8518-1-lecopzer.chen@mediatek.com> References: <20220427161340.8518-1-lecopzer.chen@mediatek.com> MIME-Version: 1.0 X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Set safe maximum CPU frequency to 5 GHz in case a particular platform doesn't implement cpufreq driver. Although, architecture doesn't put any restrictions on maximum frequency but 5 GHz seems to be safe maximum given the available Arm CPUs in the market which are clocked much less than 5 GHz. On the other hand, we can't make it much higher as it would lead to a large hard-lockup detection timeout on parts which are running slower (eg. 1GHz on Developerbox) and doesn't possess a cpufreq driver. Co-developed-by: Sumit Garg Signed-off-by: Sumit Garg Co-developed-by: Pingfan Liu Signed-off-by: Pingfan Liu Signed-off-by: Lecopzer Chen --- arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/watchdog_hld.c | 25 +++++++++++++++++++++++++ 2 files changed, 26 insertions(+) create mode 100644 arch/arm64/kernel/watchdog_hld.c diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 986837d7ec82..cd238b92d6d3 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -46,6 +46,7 @@ obj-$(CONFIG_MODULES) +=3D module.o obj-$(CONFIG_ARM64_MODULE_PLTS) +=3D module-plts.o obj-$(CONFIG_PERF_EVENTS) +=3D perf_regs.o perf_callchain.o obj-$(CONFIG_HW_PERF_EVENTS) +=3D perf_event.o +obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF) +=3D watchdog_hld.o obj-$(CONFIG_HAVE_HW_BREAKPOINT) +=3D hw_breakpoint.o obj-$(CONFIG_CPU_PM) +=3D sleep.o suspend.o obj-$(CONFIG_CPU_IDLE) +=3D cpuidle.o diff --git a/arch/arm64/kernel/watchdog_hld.c b/arch/arm64/kernel/watchdog_= hld.c new file mode 100644 index 000000000000..de43318e4dd6 --- /dev/null +++ b/arch/arm64/kernel/watchdog_hld.c @@ -0,0 +1,25 @@ +// SPDX-License-Identifier: GPL-2.0 +#include + +/* + * Safe maximum CPU frequency in case a particular platform doesn't implem= ent + * cpufreq driver. Although, architecture doesn't put any restrictions on + * maximum frequency but 5 GHz seems to be safe maximum given the available + * Arm CPUs in the market which are clocked much less than 5 GHz. On the o= ther + * hand, we can't make it much higher as it would lead to a large hard-loc= kup + * detection timeout on parts which are running slower (eg. 1GHz on + * Developerbox) and doesn't possess a cpufreq driver. + */ +#define SAFE_MAX_CPU_FREQ 5000000000UL // 5 GHz +u64 hw_nmi_get_sample_period(int watchdog_thresh) +{ + unsigned int cpu =3D smp_processor_id(); + unsigned long max_cpu_freq; + + max_cpu_freq =3D cpufreq_get_hw_max_freq(cpu) * 1000UL; + if (!max_cpu_freq) + max_cpu_freq =3D SAFE_MAX_CPU_FREQ; + + return (u64)max_cpu_freq * watchdog_thresh; +} + --=20 2.25.1