Initial import

1 files changed, 173 insertions, 0 deletions

diff --git a/arch/x86/kernel/topology.c b/arch/x86/kernel/topology.c
new file mode 100644
index 000000000..649b010da
--- /dev/null
+++ b/arch/x86/kernel/topology.c
@@ -0,0 +1,173 @@
+/*
+ * 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/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 __ref _debug_hotplug_cpu(int cpu, int action)
+{
+	struct device *dev = get_cpu_device(cpu);
+	int ret;
+
+	if (!cpu_is_hotpluggable(cpu))
+		return -EINVAL;
+
+	lock_device_hotplug();
+
+	switch (action) {
+	case 0:
+		ret = cpu_down(cpu);
+		if (!ret) {
+			pr_info("CPU %u is now offline\n", cpu);
+			dev->offline = true;
+			kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
+		} else
+			pr_debug("Can't offline CPU%d.\n", cpu);
+		break;
+	case 1:
+		ret = cpu_up(cpu);
+		if (!ret) {
+			dev->offline = false;
+			kobject_uevent(&dev->kobj, KOBJ_ONLINE);
+		} else {
+			pr_debug("Can't online CPU%d.\n", cpu);
+		}
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	unlock_device_hotplug();
+
+	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 __ref 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.
+	 */
+	if (c->x86_vendor != X86_VENDOR_INTEL)
+		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);