cpu.c revision 9d1fe3236a1d64ab687e16b4cbbaa1383352a2c1
1/* 2 * drivers/base/cpu.c - basic CPU class support 3 */ 4 5#include <linux/sysdev.h> 6#include <linux/module.h> 7#include <linux/init.h> 8#include <linux/sched.h> 9#include <linux/cpu.h> 10#include <linux/topology.h> 11#include <linux/device.h> 12#include <linux/node.h> 13 14#include "base.h" 15 16struct sysdev_class cpu_sysdev_class = { 17 .name = "cpu", 18}; 19EXPORT_SYMBOL(cpu_sysdev_class); 20 21static struct sys_device *cpu_sys_devices[NR_CPUS]; 22 23#ifdef CONFIG_HOTPLUG_CPU 24static ssize_t show_online(struct sys_device *dev, char *buf) 25{ 26 struct cpu *cpu = container_of(dev, struct cpu, sysdev); 27 28 return sprintf(buf, "%u\n", !!cpu_online(cpu->sysdev.id)); 29} 30 31static ssize_t store_online(struct sys_device *dev, const char *buf, 32 size_t count) 33{ 34 struct cpu *cpu = container_of(dev, struct cpu, sysdev); 35 ssize_t ret; 36 37 switch (buf[0]) { 38 case '0': 39 ret = cpu_down(cpu->sysdev.id); 40 if (!ret) 41 kobject_uevent(&dev->kobj, KOBJ_OFFLINE); 42 break; 43 case '1': 44 ret = cpu_up(cpu->sysdev.id); 45 if (!ret) 46 kobject_uevent(&dev->kobj, KOBJ_ONLINE); 47 break; 48 default: 49 ret = -EINVAL; 50 } 51 52 if (ret >= 0) 53 ret = count; 54 return ret; 55} 56static SYSDEV_ATTR(online, 0644, show_online, store_online); 57 58static void __devinit register_cpu_control(struct cpu *cpu) 59{ 60 sysdev_create_file(&cpu->sysdev, &attr_online); 61} 62void unregister_cpu(struct cpu *cpu) 63{ 64 int logical_cpu = cpu->sysdev.id; 65 66 unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu)); 67 68 sysdev_remove_file(&cpu->sysdev, &attr_online); 69 70 sysdev_unregister(&cpu->sysdev); 71 cpu_sys_devices[logical_cpu] = NULL; 72 return; 73} 74#else /* ... !CONFIG_HOTPLUG_CPU */ 75static inline void register_cpu_control(struct cpu *cpu) 76{ 77} 78#endif /* CONFIG_HOTPLUG_CPU */ 79 80#ifdef CONFIG_KEXEC 81#include <linux/kexec.h> 82 83static ssize_t show_crash_notes(struct sys_device *dev, char *buf) 84{ 85 struct cpu *cpu = container_of(dev, struct cpu, sysdev); 86 ssize_t rc; 87 unsigned long long addr; 88 int cpunum; 89 90 cpunum = cpu->sysdev.id; 91 92 /* 93 * Might be reading other cpu's data based on which cpu read thread 94 * has been scheduled. But cpu data (memory) is allocated once during 95 * boot up and this data does not change there after. Hence this 96 * operation should be safe. No locking required. 97 */ 98 addr = __pa(per_cpu_ptr(crash_notes, cpunum)); 99 rc = sprintf(buf, "%Lx\n", addr); 100 return rc; 101} 102static SYSDEV_ATTR(crash_notes, 0400, show_crash_notes, NULL); 103#endif 104 105/* 106 * Print cpu online, possible, present, and system maps 107 */ 108static ssize_t print_cpus_map(char *buf, cpumask_t *map) 109{ 110 int n = cpulist_scnprintf(buf, PAGE_SIZE-2, *map); 111 112 buf[n++] = '\n'; 113 buf[n] = '\0'; 114 return n; 115} 116 117#define print_cpus_func(type) \ 118static ssize_t print_cpus_##type(struct sysdev_class *class, char *buf) \ 119{ \ 120 return print_cpus_map(buf, &cpu_##type##_map); \ 121} \ 122struct sysdev_class_attribute attr_##type##_map = \ 123 _SYSDEV_CLASS_ATTR(type, 0444, print_cpus_##type, NULL) 124 125print_cpus_func(online); 126print_cpus_func(possible); 127print_cpus_func(present); 128 129struct sysdev_class_attribute *cpu_state_attr[] = { 130 &attr_online_map, 131 &attr_possible_map, 132 &attr_present_map, 133}; 134 135static int cpu_states_init(void) 136{ 137 int i; 138 int err = 0; 139 140 for (i = 0; i < ARRAY_SIZE(cpu_state_attr); i++) { 141 int ret; 142 ret = sysdev_class_create_file(&cpu_sysdev_class, 143 cpu_state_attr[i]); 144 if (!err) 145 err = ret; 146 } 147 return err; 148} 149 150/* 151 * register_cpu - Setup a sysfs device for a CPU. 152 * @cpu - cpu->hotpluggable field set to 1 will generate a control file in 153 * sysfs for this CPU. 154 * @num - CPU number to use when creating the device. 155 * 156 * Initialize and register the CPU device. 157 */ 158int __cpuinit register_cpu(struct cpu *cpu, int num) 159{ 160 int error; 161 cpu->node_id = cpu_to_node(num); 162 cpu->sysdev.id = num; 163 cpu->sysdev.cls = &cpu_sysdev_class; 164 165 error = sysdev_register(&cpu->sysdev); 166 167 if (!error && cpu->hotpluggable) 168 register_cpu_control(cpu); 169 if (!error) 170 cpu_sys_devices[num] = &cpu->sysdev; 171 if (!error) 172 register_cpu_under_node(num, cpu_to_node(num)); 173 174#ifdef CONFIG_KEXEC 175 if (!error) 176 error = sysdev_create_file(&cpu->sysdev, &attr_crash_notes); 177#endif 178 return error; 179} 180 181struct sys_device *get_cpu_sysdev(unsigned cpu) 182{ 183 if (cpu < NR_CPUS) 184 return cpu_sys_devices[cpu]; 185 else 186 return NULL; 187} 188EXPORT_SYMBOL_GPL(get_cpu_sysdev); 189 190int __init cpu_dev_init(void) 191{ 192 int err; 193 194 err = sysdev_class_register(&cpu_sysdev_class); 195 if (!err) 196 err = cpu_states_init(); 197 198#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) 199 if (!err) 200 err = sched_create_sysfs_power_savings_entries(&cpu_sysdev_class); 201#endif 202 203 return err; 204} 205