Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757749Ab2EIIDs (ORCPT ); Wed, 9 May 2012 04:03:48 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:47397 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750722Ab2EIIDn (ORCPT ); Wed, 9 May 2012 04:03:43 -0400 Date: Wed, 9 May 2012 11:03:35 +0300 From: Ido Yariv To: Ingo Molnar Cc: hpa@zytor.com, linux-kernel@vger.kernel.org, shai@scalemp.com, tglx@linutronix.de, linux-tip-commits@vger.kernel.org Subject: Re: [tip:x86/platform] vsmp: Fix number of CPUs when vsmp is disabled Message-ID: <20120509080335.GA5556@NoteStation.colubris.lan> References: <1336462455-22544-1-git-send-email-ido@wizery.com> <20120508122548.GA5741@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20120508122548.GA5741@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3227 Lines: 118 Hi Ingo, On Tue, May 08, 2012 at 02:25:49PM +0200, Ingo Molnar wrote: > > On !CONFIG_SMP this produces the following build failure: > > arch/x86/kernel/vsmp_64.c:171:6: error: ‘setup_max_cpus’ undeclared (first use in this function) > > Do you want to keep vSMP on UP? If not then you could add a > 'depends on SMP' to the vSMP Kconfig entry, avoiding the whole > UP problem space. Oops, sorry for that. vsmp_64.c is built even if CONFIG_X86_VSMP is not set, so even if we set this dependency, it will not fix this issue. How about the following CONFIG_SMP check instead? Thanks, Ido. >From b3c6d985b101364dd74f0efaf42c6b34fc7615f9 Mon Sep 17 00:00:00 2001 From: Shai Fultheim Date: Mon, 16 Apr 2012 10:39:35 +0300 Subject: [PATCH] vsmp: Fix number of CPUs when vsmp is disabled In case CONFIG_X86_VSMP is not set, limit the number of CPUs to the number of CPUs of the first board. Signed-off-by: Shai Fultheim [ido@wizery.com: rebased, fixed minor coding-style issues] Signed-off-by: Ido Yariv --- arch/x86/kernel/vsmp_64.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 43 insertions(+), 0 deletions(-) diff --git a/arch/x86/kernel/vsmp_64.c b/arch/x86/kernel/vsmp_64.c index a1d804b..06779b7 100644 --- a/arch/x86/kernel/vsmp_64.c +++ b/arch/x86/kernel/vsmp_64.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include @@ -22,6 +23,8 @@ #include #include +#define TOPOLOGY_REGISTER_OFFSET 0x10 + #if defined CONFIG_PCI && defined CONFIG_PARAVIRT /* * Interrupt control on vSMPowered systems: @@ -149,12 +152,52 @@ int is_vsmp_box(void) return 0; } #endif + +static void __init vsmp_cap_cpus(void) +{ + void __iomem *address; + unsigned int cfg, topology, node_shift, maxcpus; + +#ifdef CONFIG_X86_VSMP + /* VSMP is enabled, no need to cap cpus */ + return; +#elif CONFIG_SMP + /* + * CONFIG_X86_VSMP is not configured, so limit the number CPUs to the + * ones present in the first board, unless explicitly overridden by + * setup_max_cpus + */ + if (setup_max_cpus != NR_CPUS) + return; + + /* Read the vSMP Foundation topology register */ + cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0); + address = early_ioremap(cfg + TOPOLOGY_REGISTER_OFFSET, 4); + if (WARN_ON(!address)) + return; + + topology = readl(address); + node_shift = (topology >> 16) & 0x7; + if (!node_shift) + /* The value 0 should be decoded as 8 */ + node_shift = 8; + maxcpus = (topology & ((1 << node_shift) - 1)) + 1; + + pr_info("vSMP CTL: Capping CPUs to %d (CONFIG_X86_VSMP is unset)\n", + maxcpus); + setup_max_cpus = maxcpus; + early_iounmap(address, 4); +#endif +} + void __init vsmp_init(void) { detect_vsmp_box(); if (!is_vsmp_box()) return; + vsmp_cap_cpus(); + set_vsmp_pv_ops(); return; } -- 1.7.6.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/