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=-11.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 37BE0C4321A for ; Thu, 27 Jun 2019 23:42:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 088EA208E3 for ; Thu, 27 Jun 2019 23:42:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="sRRDHVKs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726838AbfF0XmF (ORCPT ); Thu, 27 Jun 2019 19:42:05 -0400 Received: from terminus.zytor.com ([198.137.202.136]:52589 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726566AbfF0XmF (ORCPT ); Thu, 27 Jun 2019 19:42:05 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id x5RNfnmV500531 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Thu, 27 Jun 2019 16:41:49 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 terminus.zytor.com x5RNfnmV500531 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2019061801; t=1561678909; bh=cfxfvkVxTcd6HLaYvJVL+i37CI6+stAG2SEKQa7Y89c=; h=Date:From:Cc:Reply-To:In-Reply-To:References:To:Subject:From; b=sRRDHVKs/uvRe+IUKEtWWfwhJnr+V+CRPJbu0OT+iUf9j+ADG/KxDREb9jLO+sKOH KD1TxvU3LX/FoNrsR8hrtA+xexyDOTCWsUSPaYbjMGZ1RQwPCohHdCPFFryJmmCbaP PO0LCGGCddPBxlBqiwUjVpMyMCd9WTI23Wbk8stfIR0TkUJOVzs8jqLHH5mH/a+1+f VVxk66++Ek+Gw3FRpVWAHDK3MK7vsQy62RCVUjHp+97h7jIdn3uz+owl9B17Q3eV5V 1Hosv0MdaM32WcyGxOW7xulmeO5m0L1zeJMgev3HCsZKRnguDs+czm0ooGTGr3cfXa JJ5/L002aiEzQ== Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id x5RNfmnj500528; Thu, 27 Jun 2019 16:41:48 -0700 Date: Thu, 27 Jun 2019 16:41:48 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Thomas Gleixner Message-ID: Cc: tglx@linutronix.de, eranian@google.com, linux-kernel@vger.kernel.org, ravi.v.shankar@intel.com, andi.kleen@intel.com, Suravee.Suthikulpanit@amd.com, peterz@infradead.org, hpa@zytor.com, mingo@kernel.org, ricardo.neri-calderon@linux.intel.com, ashok.raj@intel.com Reply-To: hpa@zytor.com, ravi.v.shankar@intel.com, mingo@kernel.org, ricardo.neri-calderon@linux.intel.com, ashok.raj@intel.com, andi.kleen@intel.com, tglx@linutronix.de, eranian@google.com, linux-kernel@vger.kernel.org, Suravee.Suthikulpanit@amd.com, peterz@infradead.org In-Reply-To: <20190623132435.149535103@linutronix.de> References: <20190623132435.149535103@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/timers] x86/hpet: Simplify counter validation Git-Commit-ID: 44b5be5733e119300115b98409cbcf9a45b8d3f1 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 44b5be5733e119300115b98409cbcf9a45b8d3f1 Gitweb: https://git.kernel.org/tip/44b5be5733e119300115b98409cbcf9a45b8d3f1 Author: Thomas Gleixner AuthorDate: Sun, 23 Jun 2019 15:23:52 +0200 Committer: Thomas Gleixner CommitDate: Fri, 28 Jun 2019 00:57:19 +0200 x86/hpet: Simplify counter validation There is no point to loop for 200k TSC cycles to check afterwards whether the HPET counter is working. Read the counter inside of the loop and break out when the counter value changed. Signed-off-by: Thomas Gleixner Reviewed-by: Ingo Molnar Cc: Peter Zijlstra Cc: Ricardo Neri Cc: Ashok Raj Cc: Andi Kleen Cc: Suravee Suthikulpanit Cc: Stephane Eranian Cc: Ravi Shankar Link: https://lkml.kernel.org/r/20190623132435.149535103@linutronix.de --- arch/x86/kernel/hpet.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index 8c57dbf15e3b..74756c0a3a10 100644 --- a/arch/x86/kernel/hpet.c +++ b/arch/x86/kernel/hpet.c @@ -853,15 +853,13 @@ static bool __init hpet_counting(void) * 1 GHz == 200us */ do { - rep_nop(); + if (t1 != hpet_readl(HPET_COUNTER)) + return true; now = rdtsc(); } while ((now - start) < 200000UL); - if (t1 == hpet_readl(HPET_COUNTER)) { - pr_warn("Counter not counting. HPET disabled\n"); - return false; - } - return true; + pr_warn("Counter not counting. HPET disabled\n"); + return false; } /**