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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED, 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 4ED97C433DB for ; Mon, 28 Dec 2020 13:34:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1FFFC208BA for ; Mon, 28 Dec 2020 13:34:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388017AbgL1Ndx (ORCPT ); Mon, 28 Dec 2020 08:33:53 -0500 Received: from mail.kernel.org ([198.145.29.99]:33044 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387827AbgL1NdA (ORCPT ); Mon, 28 Dec 2020 08:33:00 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 78D712072C; Mon, 28 Dec 2020 13:32:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609162365; bh=DqaDuenVWDuPim+nlw0OQY6Pd9PF9YPO0SjC34NwOXQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Cg5M/3qgGwQk3VSCX1dDwtD8wJ7hdQiSo+Ae/W/U87PBeI59XHg6H/5hwSwQdtIEK yvx3MLzycv2ugSDf/3102MMNde1YeJ/6sV09wtgGdWhd1FkKTqg1TJUIlgC2ChNZSW /CCnNbG7HxrkZU3LSXFVOyWAZNcfaDSVFDMf5OJE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Heiko Carstens , Sven Schnelle , stable@kernel.org Subject: [PATCH 4.19 279/346] s390/smp: perform initial CPU reset also for SMT siblings Date: Mon, 28 Dec 2020 13:49:58 +0100 Message-Id: <20201228124933.267704720@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228124919.745526410@linuxfoundation.org> References: <20201228124919.745526410@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sven Schnelle commit b5e438ebd7e808d1d2435159ac4742e01a94b8da upstream. Not resetting the SMT siblings might leave them in unpredictable state. One of the observed problems was that the CPU timer wasn't reset and therefore large system time values where accounted during CPU bringup. Cc: # 4.0 Fixes: 10ad34bc76dfb ("s390: add SMT support") Reviewed-by: Heiko Carstens Signed-off-by: Sven Schnelle Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman --- arch/s390/kernel/smp.c | 18 +++--------------- 1 file changed, 3 insertions(+), 15 deletions(-) --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -863,24 +863,12 @@ static void smp_start_secondary(void *cp /* Upping and downing of CPUs */ int __cpu_up(unsigned int cpu, struct task_struct *tidle) { - struct pcpu *pcpu; - int base, i, rc; + struct pcpu *pcpu = pcpu_devices + cpu; + int rc; - pcpu = pcpu_devices + cpu; if (pcpu->state != CPU_STATE_CONFIGURED) return -EIO; - base = smp_get_base_cpu(cpu); - for (i = 0; i <= smp_cpu_mtid; i++) { - if (base + i < nr_cpu_ids) - if (cpu_online(base + i)) - break; - } - /* - * If this is the first CPU of the core to get online - * do an initial CPU reset. - */ - if (i > smp_cpu_mtid && - pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) != + if (pcpu_sigp_retry(pcpu, SIGP_INITIAL_CPU_RESET, 0) != SIGP_CC_ORDER_CODE_ACCEPTED) return -EIO;