/* * 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);