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Diffstat (limited to '')
| -rw-r--r-- | arch/x86/kernel/topology.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/arch/x86/kernel/topology.c b/arch/x86/kernel/topology.c new file mode 100644 index 000000000..0a2ec801b --- /dev/null +++ b/arch/x86/kernel/topology.c @@ -0,0 +1,166 @@ +/* + * Populate sysfs with topology information + * + * Written by: Matthew Dobson, IBM Corporation + * Original Code: Paul Dorwin, IBM Corporation, Patrick Mochel, OSDL + * + * Copyright (C) 2002, IBM Corp. + * + * All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for more + * details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * + * Send feedback to <colpatch@us.ibm.com> + */ +#include <linux/nodemask.h> +#include <linux/export.h> +#include <linux/mmzone.h> +#include <linux/init.h> +#include <linux/smp.h> +#include <linux/irq.h> +#include <asm/io_apic.h> +#include <asm/cpu.h> + +static DEFINE_PER_CPU(struct x86_cpu, cpu_devices); + +#ifdef CONFIG_HOTPLUG_CPU + +#ifdef CONFIG_BOOTPARAM_HOTPLUG_CPU0 +static int cpu0_hotpluggable = 1; +#else +static int cpu0_hotpluggable; +static int __init enable_cpu0_hotplug(char *str) +{ + cpu0_hotpluggable = 1; + return 1; +} + +__setup("cpu0_hotplug", enable_cpu0_hotplug); +#endif + +#ifdef CONFIG_DEBUG_HOTPLUG_CPU0 +/* + * This function offlines a CPU as early as possible and allows userspace to + * boot up without the CPU. The CPU can be onlined back by user after boot. + * + * This is only called for debugging CPU offline/online feature. + */ +int _debug_hotplug_cpu(int cpu, int action) +{ + int ret; + + if (!cpu_is_hotpluggable(cpu)) + return -EINVAL; + + switch (action) { + case 0: + ret = remove_cpu(cpu); + if (!ret) + pr_info("DEBUG_HOTPLUG_CPU0: CPU %u is now offline\n", cpu); + else + pr_debug("Can't offline CPU%d.\n", cpu); + break; + case 1: + ret = add_cpu(cpu); + if (ret) + pr_debug("Can't online CPU%d.\n", cpu); + + break; + default: + ret = -EINVAL; + } + + return ret; +} + +static int __init debug_hotplug_cpu(void) +{ + _debug_hotplug_cpu(0, 0); + return 0; +} + +late_initcall_sync(debug_hotplug_cpu); +#endif /* CONFIG_DEBUG_HOTPLUG_CPU0 */ + +int arch_register_cpu(int num) +{ + struct cpuinfo_x86 *c = &cpu_data(num); + + /* + * Currently CPU0 is only hotpluggable on Intel platforms. Other + * vendors can add hotplug support later. + * Xen PV guests don't support CPU0 hotplug at all. + */ + if (c->x86_vendor != X86_VENDOR_INTEL || + boot_cpu_has(X86_FEATURE_XENPV)) + cpu0_hotpluggable = 0; + + /* + * Two known BSP/CPU0 dependencies: Resume from suspend/hibernate + * depends on BSP. PIC interrupts depend on BSP. + * + * If the BSP depencies are under control, one can tell kernel to + * enable BSP hotplug. This basically adds a control file and + * one can attempt to offline BSP. + */ + if (num == 0 && cpu0_hotpluggable) { + unsigned int irq; + /* + * We won't take down the boot processor on i386 if some + * interrupts only are able to be serviced by the BSP in PIC. + */ + for_each_active_irq(irq) { + if (!IO_APIC_IRQ(irq) && irq_has_action(irq)) { + cpu0_hotpluggable = 0; + break; + } + } + } + if (num || cpu0_hotpluggable) + per_cpu(cpu_devices, num).cpu.hotpluggable = 1; + + return register_cpu(&per_cpu(cpu_devices, num).cpu, num); +} +EXPORT_SYMBOL(arch_register_cpu); + +void arch_unregister_cpu(int num) +{ + unregister_cpu(&per_cpu(cpu_devices, num).cpu); +} +EXPORT_SYMBOL(arch_unregister_cpu); +#else /* CONFIG_HOTPLUG_CPU */ + +static int __init arch_register_cpu(int num) +{ + return register_cpu(&per_cpu(cpu_devices, num).cpu, num); +} +#endif /* CONFIG_HOTPLUG_CPU */ + +static int __init topology_init(void) +{ + int i; + +#ifdef CONFIG_NUMA + for_each_online_node(i) + register_one_node(i); +#endif + + for_each_present_cpu(i) + arch_register_cpu(i); + + return 0; +} +subsys_initcall(topology_init); |