* tip-bot for Shai Fultheim <shai@xxxxxxxxxxx> wrote:
> Commit-ID: 824a6ae65f085255464155760cb9628a2f0deb29
> Gitweb: http://git.kernel.org/tip/824a6ae65f085255464155760cb9628a2f0deb29
> Author: Shai Fultheim <shai@xxxxxxxxxxx>
> AuthorDate: Tue, 8 May 2012 10:34:15 +0300
> Committer: Ingo Molnar <mingo@xxxxxxxxxx>
> 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 <shai@xxxxxxxxxxx>
> [ido@xxxxxxxxxx: rebased, fixed minor coding-style issues]
> Signed-off-by: Ido Yariv <ido@xxxxxxxxxx>
> Link: http://lkml.kernel.org/r/1336462455-22544-1-git-send-email-ido@xxxxxxxxxx
> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
> ---
> 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 <linux/init.h>
> #include <linux/pci_ids.h>
> #include <linux/pci_regs.h>
> +#include <linux/smp.h>
>
> #include <asm/apic.h>
> #include <asm/pci-direct.h>
> @@ -22,6 +23,8 @@
> #include <asm/paravirt.h>
> #include <asm/setup.h>
>
> +#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
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