Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754598Ab2EHMZ6 (ORCPT ); Tue, 8 May 2012 08:25:58 -0400 Received: from mail-wi0-f178.google.com ([209.85.212.178]:50002 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754503Ab2EHMZz (ORCPT ); Tue, 8 May 2012 08:25:55 -0400 Date: Tue, 8 May 2012 14:25:49 +0200 From: Ingo Molnar To: hpa@zytor.com, linux-kernel@vger.kernel.org, shai@scalemp.com, tglx@linutronix.de, ido@wizery.com Cc: linux-tip-commits@vger.kernel.org Subject: Re: [tip:x86/platform] vsmp: Fix number of CPUs when vsmp is disabled Message-ID: <20120508122548.GA5741@gmail.com> References: <1336462455-22544-1-git-send-email-ido@wizery.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: 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: 3259 Lines: 102 * tip-bot for Shai Fultheim wrote: > Commit-ID: 824a6ae65f085255464155760cb9628a2f0deb29 > Gitweb: http://git.kernel.org/tip/824a6ae65f085255464155760cb9628a2f0deb29 > Author: Shai Fultheim > AuthorDate: Tue, 8 May 2012 10:34:15 +0300 > Committer: Ingo Molnar > CommitDate: Tue, 8 May 2012 11:24:45 +0200 > > 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 > Link: http://lkml.kernel.org/r/1336462455-22544-1-git-send-email-ido@wizery.com > Signed-off-by: Ingo Molnar > --- > 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..6aa0d59 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; > +#endif > + > + /* > + * 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); 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. Thanks, Ingo -- 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/