157 lines
3.5 KiB
C
157 lines
3.5 KiB
C
/*
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* drivers/base/cpu.c - basic CPU class support
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*/
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#include <linux/sysdev.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/cpu.h>
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#include <linux/topology.h>
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#include <linux/device.h>
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#include "base.h"
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struct sysdev_class cpu_sysdev_class = {
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set_kset_name("cpu"),
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};
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EXPORT_SYMBOL(cpu_sysdev_class);
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static struct sys_device *cpu_sys_devices[NR_CPUS];
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#ifdef CONFIG_HOTPLUG_CPU
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int __attribute__((weak)) smp_prepare_cpu (int cpu)
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{
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return 0;
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}
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static ssize_t show_online(struct sys_device *dev, char *buf)
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{
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struct cpu *cpu = container_of(dev, struct cpu, sysdev);
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return sprintf(buf, "%u\n", !!cpu_online(cpu->sysdev.id));
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}
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static ssize_t store_online(struct sys_device *dev, const char *buf,
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size_t count)
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{
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struct cpu *cpu = container_of(dev, struct cpu, sysdev);
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ssize_t ret;
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switch (buf[0]) {
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case '0':
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ret = cpu_down(cpu->sysdev.id);
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if (!ret)
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kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
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break;
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case '1':
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ret = smp_prepare_cpu(cpu->sysdev.id);
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if (!ret)
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ret = cpu_up(cpu->sysdev.id);
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if (!ret)
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kobject_uevent(&dev->kobj, KOBJ_ONLINE);
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break;
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default:
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ret = -EINVAL;
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}
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if (ret >= 0)
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ret = count;
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return ret;
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}
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static SYSDEV_ATTR(online, 0600, show_online, store_online);
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static void __devinit register_cpu_control(struct cpu *cpu)
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{
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sysdev_create_file(&cpu->sysdev, &attr_online);
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}
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void unregister_cpu(struct cpu *cpu, struct node *root)
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{
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int logical_cpu = cpu->sysdev.id;
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if (root)
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sysfs_remove_link(&root->sysdev.kobj,
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kobject_name(&cpu->sysdev.kobj));
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sysdev_remove_file(&cpu->sysdev, &attr_online);
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sysdev_unregister(&cpu->sysdev);
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cpu_sys_devices[logical_cpu] = NULL;
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return;
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}
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#else /* ... !CONFIG_HOTPLUG_CPU */
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static inline void register_cpu_control(struct cpu *cpu)
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{
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}
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#endif /* CONFIG_HOTPLUG_CPU */
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#ifdef CONFIG_KEXEC
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#include <linux/kexec.h>
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static ssize_t show_crash_notes(struct sys_device *dev, char *buf)
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{
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struct cpu *cpu = container_of(dev, struct cpu, sysdev);
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ssize_t rc;
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unsigned long long addr;
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int cpunum;
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cpunum = cpu->sysdev.id;
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/*
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* Might be reading other cpu's data based on which cpu read thread
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* has been scheduled. But cpu data (memory) is allocated once during
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* boot up and this data does not change there after. Hence this
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* operation should be safe. No locking required.
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*/
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addr = __pa(per_cpu_ptr(crash_notes, cpunum));
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rc = sprintf(buf, "%Lx\n", addr);
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return rc;
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}
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static SYSDEV_ATTR(crash_notes, 0400, show_crash_notes, NULL);
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#endif
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/*
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* register_cpu - Setup a driverfs device for a CPU.
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* @cpu - Callers can set the cpu->no_control field to 1, to indicate not to
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* generate a control file in sysfs for this CPU.
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* @num - CPU number to use when creating the device.
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*
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* Initialize and register the CPU device.
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*/
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int __devinit register_cpu(struct cpu *cpu, int num, struct node *root)
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{
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int error;
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cpu->node_id = cpu_to_node(num);
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cpu->sysdev.id = num;
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cpu->sysdev.cls = &cpu_sysdev_class;
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error = sysdev_register(&cpu->sysdev);
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if (!error && root)
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error = sysfs_create_link(&root->sysdev.kobj,
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&cpu->sysdev.kobj,
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kobject_name(&cpu->sysdev.kobj));
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if (!error && !cpu->no_control)
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register_cpu_control(cpu);
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if (!error)
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cpu_sys_devices[num] = &cpu->sysdev;
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#ifdef CONFIG_KEXEC
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if (!error)
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error = sysdev_create_file(&cpu->sysdev, &attr_crash_notes);
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#endif
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return error;
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}
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struct sys_device *get_cpu_sysdev(int cpu)
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{
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if (cpu < NR_CPUS)
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return cpu_sys_devices[cpu];
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else
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return NULL;
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}
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EXPORT_SYMBOL_GPL(get_cpu_sysdev);
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int __init cpu_dev_init(void)
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{
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return sysdev_class_register(&cpu_sysdev_class);
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}
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