From patchwork Fri Jun 12 11:51:59 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: You-Sheng Yang X-Patchwork-Id: 1308133 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lists.ubuntu.com (client-ip=91.189.94.19; helo=huckleberry.canonical.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=canonical.com Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 49jzc14yw4z9sT9; Fri, 12 Jun 2020 21:52:17 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.86_2) (envelope-from ) id 1jjiEC-0004fX-If; Fri, 12 Jun 2020 11:52:08 +0000 Received: from mail-pf1-f196.google.com ([209.85.210.196]) by huckleberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1jjiEA-0004fK-EI for kernel-team@lists.ubuntu.com; Fri, 12 Jun 2020 11:52:06 +0000 Received: by mail-pf1-f196.google.com with SMTP id 23so4177856pfw.10 for ; Fri, 12 Jun 2020 04:52:06 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:mime-version :content-transfer-encoding; bh=WXlj4n4MC/1lkQomOZUIDLpstMomFJPLIz3fcM9qWhg=; b=alGA2Eo2n7X+eSEWwCeGOMqndN+zbBA+iQeU2uNTWSCU195TGGj2qgtlIsYEjVW6t2 Facb+NObPZHV4/jQV4yYH+OIsPHUEZXTR3/owz6fvbwFI0gDJedY6X71EsmVYTCHOs/D c5dXCb/4DxBBgLpb5w59OkWN/+8xM07wJE3FF/l6KJptnQ8MBgPsubq+Ttw9ExVuppbD 7JlVj/tU2chfB+etRCaa82tne96L34G8VzlesjVIlSq5csaU8U1YQDlplCX/atEviWyL V+h81/iPgFhT2eRY6WpURRDKABGMuFlxcaVTTh6zEBmjO8MIXHeJTE+q/oGop3oVNBGb pVsg== X-Gm-Message-State: AOAM532PqJD0k63MM3uDqHjcTJm//vY0NN1ZpgRB6fok8rEParV7wr0+ rOb+vpUR+rwnG6VcHkBSIymU1pTE X-Google-Smtp-Source: ABdhPJx8JxTdOmiOewN5Zgin6ByhqGNZdYVJI6LiuUPMOK/CQrrp/Wq/IJhIk85g7Za5ElzOFzjOIw== X-Received: by 2002:a62:2b55:: with SMTP id r82mr11874648pfr.68.1591962724025; Fri, 12 Jun 2020 04:52:04 -0700 (PDT) Received: from localhost (61-220-137-37.HINET-IP.hinet.net. [61.220.137.37]) by smtp.gmail.com with ESMTPSA id p31sm5380835pgb.46.2020.06.12.04.52.01 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Jun 2020 04:52:02 -0700 (PDT) From: You-Sheng Yang To: kernel-team@lists.ubuntu.com Subject: [PATCH 0/1][SRU][B/OEM-B] Fix boot regression caused by a disabled PIT Date: Fri, 12 Jun 2020 19:51:59 +0800 Message-Id: <20200612115200.1006881-1-vicamo.yang@canonical.com> X-Mailer: git-send-email 2.27.0.rc0 MIME-Version: 1.0 X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" BugLink: https://bugs.launchpad.net/bugs/1856387 [Impact] In bug 1840239, HPET is disabled on some systems for they caused TSC being marked unstable while it is not. This caused an regression as bug 1851216 that some systems may then hang at early, so a fix cherry picked back from v5.3-rc1. However, this fix also introduce yet another regression that some other users may hang at boot while PIT is diabled in the previous fix. [Fix] Commit 979923871f69 ("x86/timer: Don't skip PIT setup when APIC is disabled or in legacy mode") from v5.6-rc1, also backported to v5.4.19 and v5.5.3, fixes PIT setup in this case. [Test Case] Simply boot a patch kernel on systems affected and it shouldn't hang. [Regression Potential] Low. Stable patch and trivial backport. [Other Info] The same fix for bug 1851216 was also backported to Disco and Eoan, but they were then fixed with this 979923871f69 commit backported in bug 1866858 and bug 1867051, which pulls v5.4 stable patches into Disco and Eoan correspondingly, leaving B/OEM-B the only victims so far. Thomas Gleixner (1): x86/timer: Don't skip PIT setup when APIC is disabled or in legacy mode arch/x86/include/asm/apic.h | 2 ++ arch/x86/include/asm/x86_init.h | 2 ++ arch/x86/kernel/apic/apic.c | 23 ++++++++++++++++++----- arch/x86/kernel/time.c | 12 ++++++++++-- arch/x86/kernel/x86_init.c | 1 + arch/x86/xen/enlighten_pv.c | 1 + 6 files changed, 34 insertions(+), 7 deletions(-) Acked-By: AceLan Kao