From patchwork Tue Dec 14 12:32:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Woodhouse X-Patchwork-Id: 12675951 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 5D2DCC433EF for ; Tue, 14 Dec 2021 12:33:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234091AbhLNMd1 (ORCPT ); Tue, 14 Dec 2021 07:33:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33698 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231874AbhLNMdT (ORCPT ); Tue, 14 Dec 2021 07:33:19 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9E031C061751; Tue, 14 Dec 2021 04:33:18 -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=Bnbhj7ihFtIpOJMjxQiXBxGy6h EzMuCtnk3of2LeWv63BU0njVYEn96WhKjq6lzaXbksIxDZST5VBk9wFG6ZNchO+o9xslZ/C1P5wxx Ym/TPohH8ETqpEDdzDamhQUzOaa5Gqcntl/LMpxTHGek6AVygpCELAsQSiMA5qm8w39zJwJn34dfW n3WH4pLOMSIbfUBJCyzT79cgs3HU30EQt1cYxx8dtMDQk3YwxGLFAsmivF4RRwqgF6gNtvz05potl RiC3rl448+vh8AqAdYrILUMNYZzGELv4Ie8dtKcIFsFkh9d9WTZmNtHUBgGsGMB2fIsQVDMT9ES83 Dqmj4nlw==; 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 1mx6zE-00DhTF-FF; Tue, 14 Dec 2021 12:32:53 +0000 Received: from dwoodhou by i7.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mx6zE-000N6b-MP; Tue, 14 Dec 2021 12:32:52 +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 v2 4/7] x86/smpboot: Reference count on smpboot_setup_warm_reset_vector() Date: Tue, 14 Dec 2021 12:32:47 +0000 Message-Id: <20211214123250.88230-5-dwmw2@infradead.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211214123250.88230-1-dwmw2@infradead.org> References: <20211214123250.88230-1-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);