x86/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. Also make CONFIG_X86_VSMP depend on CONFIG_SMP, as there's little point in having a vsmp machine with a single CPU. Signed-off-by: Shai Fultheim <shai@scalemp.com> [ido@wizery.com: rebased, fixed minor coding-style issues] Signed-off-by: Ido Yariv <ido@wizery.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
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@ -376,6 +376,7 @@ config X86_VSMP
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select PARAVIRT
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depends on X86_64 && PCI
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depends on X86_EXTENDED_PLATFORM
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depends on SMP
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---help---
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Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
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supposed to run on these EM64T-based machines. Only choose this option
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@ -15,6 +15,7 @@
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#include <linux/init.h>
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#include <linux/pci_ids.h>
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#include <linux/pci_regs.h>
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#include <linux/smp.h>
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#include <asm/apic.h>
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#include <asm/pci-direct.h>
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@ -22,6 +23,8 @@
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#include <asm/paravirt.h>
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#include <asm/setup.h>
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#define TOPOLOGY_REGISTER_OFFSET 0x10
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#if defined CONFIG_PCI && defined CONFIG_PARAVIRT
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/*
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* Interrupt control on vSMPowered systems:
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@ -149,12 +152,49 @@ int is_vsmp_box(void)
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return 0;
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}
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#endif
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static void __init vsmp_cap_cpus(void)
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{
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#if !defined(CONFIG_X86_VSMP) && defined(CONFIG_SMP)
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void __iomem *address;
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unsigned int cfg, topology, node_shift, maxcpus;
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/*
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* CONFIG_X86_VSMP is not configured, so limit the number CPUs to the
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* ones present in the first board, unless explicitly overridden by
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* setup_max_cpus
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*/
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if (setup_max_cpus != NR_CPUS)
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return;
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/* Read the vSMP Foundation topology register */
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cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
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address = early_ioremap(cfg + TOPOLOGY_REGISTER_OFFSET, 4);
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if (WARN_ON(!address))
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return;
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topology = readl(address);
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node_shift = (topology >> 16) & 0x7;
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if (!node_shift)
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/* The value 0 should be decoded as 8 */
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node_shift = 8;
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maxcpus = (topology & ((1 << node_shift) - 1)) + 1;
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pr_info("vSMP CTL: Capping CPUs to %d (CONFIG_X86_VSMP is unset)\n",
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maxcpus);
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setup_max_cpus = maxcpus;
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early_iounmap(address, 4);
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#endif
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}
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void __init vsmp_init(void)
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{
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detect_vsmp_box();
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if (!is_vsmp_box())
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return;
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vsmp_cap_cpus();
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set_vsmp_pv_ops();
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return;
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}
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