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 16 struct sysdev_class cpu_sysdev_class = { 17 .name = "cpu", 18 }; 19 EXPORT_SYMBOL(cpu_sysdev_class); 20 21 static DEFINE_PER_CPU(struct sys_device *, cpu_sys_devices); 22 23 #ifdef CONFIG_HOTPLUG_CPU 24 static 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 31 static ssize_t __ref 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 } 56 static SYSDEV_ATTR(online, 0644, show_online, store_online); 57 58 static void __cpuinit register_cpu_control(struct cpu *cpu) 59 { 60 sysdev_create_file(&cpu->sysdev, &attr_online); 61 } 62 void 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 per_cpu(cpu_sys_devices, logical_cpu) = NULL; 72 return; 73 } 74 #else /* ... !CONFIG_HOTPLUG_CPU */ 75 static 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 83 static 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 } 102 static SYSDEV_ATTR(crash_notes, 0400, show_crash_notes, NULL); 103 #endif 104 105 /* 106 * Print cpu online, possible, present, and system maps 107 */ 108 static 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) \ 118 static ssize_t print_cpus_##type(struct sysdev_class *class, char *buf) \ 119 { \ 120 return print_cpus_map(buf, &cpu_##type##_map); \ 121 } \ 122 struct sysdev_class_attribute attr_##type##_map = \ 123 _SYSDEV_CLASS_ATTR(type, 0444, print_cpus_##type, NULL) 124 125 print_cpus_func(online); 126 print_cpus_func(possible); 127 print_cpus_func(present); 128 129 struct sysdev_class_attribute *cpu_state_attr[] = { 130 &attr_online_map, 131 &attr_possible_map, 132 &attr_present_map, 133 }; 134 135 static 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 */ 158 int __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 per_cpu(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 } 180 181 struct sys_device *get_cpu_sysdev(unsigned cpu) 182 { 183 if (cpu < nr_cpu_ids && cpu_possible(cpu)) 184 return per_cpu(cpu_sys_devices, cpu); 185 else 186 return NULL; 187 } 188 EXPORT_SYMBOL_GPL(get_cpu_sysdev); 189 190 int __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