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); +} + void __init vsmp_init(void) { detect_vsmp_box(); if (!is_vsmp_box()) return; + vsmp_cap_cpus(); + set_vsmp_pv_ops(); return; } -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html