From patchwork Wed Dec 15 14:56:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Woodhouse X-Patchwork-Id: 12678499 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 C7A5DC433FE for ; Wed, 15 Dec 2021 14:57:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243619AbhLOO5a (ORCPT ); Wed, 15 Dec 2021 09:57:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56598 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243626AbhLOO5A (ORCPT ); Wed, 15 Dec 2021 09:57:00 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05BDDC061574; Wed, 15 Dec 2021 06:56:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=iwFC5dCU7PYeSu7YmExQWEMI/4v4Pyx235oHOTTX2kE=; b=lgtYr5Fnx1G2bvVj9PhxmaU19+ bW3xH7IuIzIKcCyTCDB5tX0Fengx9UdrtQJTBapZ/MB99WWdO4jdRa7bufc8p4tmfMyDAKRarzMJc ewfybCxOthnpZtJu60kbg9oBs8o8ZrpYP0Rdhi0yAtDIDrcPeQyjytXD0w/OyptX8NbOWu/i/DycC vSJUsU+Mi2xEIXGPGGTPJ3FZ4eadnEAa+mHHTb+RtCZtzLMxUvSM8+LUWdtBs6qKNhHo1wCje/hhb 8jSFDWsCdw1G+ZiyVvIdE9Jz8GJD/rTH/+mricgKd4eTk/IHrFV7YTIlc5sRwJwgBuR4UJDimTPUp Cttb3kmg==; Received: from i7.infradead.org ([2001:8b0:10b:1:21e:67ff:fecb:7a92]) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mxVhq-00EjwO-Pk; Wed, 15 Dec 2021 14:56:35 +0000 Received: from dwoodhou by i7.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mxVhr-0001Ns-1M; Wed, 15 Dec 2021 14:56:35 +0000 From: David Woodhouse To: Thomas Gleixner Cc: Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Paolo Bonzini , "Paul E . McKenney" , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, rcu@vger.kernel.org, mimoja@mimoja.de, hewenliang4@huawei.com, hushiyuan@huawei.com, luolongjun@huawei.com, hejingxian@huawei.com Subject: [PATCH v3 4/9] x86/smpboot: Reference count on smpboot_setup_warm_reset_vector() Date: Wed, 15 Dec 2021 14:56:28 +0000 Message-Id: <20211215145633.5238-5-dwmw2@infradead.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211215145633.5238-1-dwmw2@infradead.org> References: <20211215145633.5238-1-dwmw2@infradead.org> MIME-Version: 1.0 Sender: David Woodhouse X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: David Woodhouse If we want to do parallel CPU bringup, we're going to need to set this up and leave it until all CPUs are done. Might as well use the RTC spinlock to protect the refcount, as we need to take it anyway. Signed-off-by: David Woodhouse --- arch/x86/kernel/smpboot.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index ac2909f0cab3..99c705935f94 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -127,17 +127,22 @@ int arch_update_cpu_topology(void) return retval; } + +static unsigned int smpboot_warm_reset_vector_count; + static inline void smpboot_setup_warm_reset_vector(unsigned long start_eip) { unsigned long flags; spin_lock_irqsave(&rtc_lock, flags); - CMOS_WRITE(0xa, 0xf); + if (!smpboot_warm_reset_vector_count++) { + CMOS_WRITE(0xa, 0xf); + *((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_HIGH)) = + start_eip >> 4; + *((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) = + start_eip & 0xf; + } spin_unlock_irqrestore(&rtc_lock, flags); - *((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_HIGH)) = - start_eip >> 4; - *((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) = - start_eip & 0xf; } static inline void smpboot_restore_warm_reset_vector(void) @@ -149,10 +154,12 @@ static inline void smpboot_restore_warm_reset_vector(void) * to default values. */ spin_lock_irqsave(&rtc_lock, flags); - CMOS_WRITE(0, 0xf); - spin_unlock_irqrestore(&rtc_lock, flags); + if (!--smpboot_warm_reset_vector_count) { + CMOS_WRITE(0, 0xf); - *((volatile u32 *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) = 0; + *((volatile u32 *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) = 0; + } + spin_unlock_irqrestore(&rtc_lock, flags); } static void init_freq_invariance(bool secondary, bool cppc_ready);