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, struct sysdev_attribute *attr, 25 char *buf) 26 { 27 struct cpu *cpu = container_of(dev, struct cpu, sysdev); 28 29 return sprintf(buf, "%u\n", !!cpu_online(cpu->sysdev.id)); 30 } 31 32 static ssize_t __ref store_online(struct sys_device *dev, struct sysdev_attribute *attr, 33 const char *buf, size_t count) 34 { 35 struct cpu *cpu = container_of(dev, struct cpu, sysdev); 36 ssize_t ret; 37 38 cpu_hotplug_driver_lock(); 39 switch (buf[0]) { 40 case '0': 41 ret = cpu_down(cpu->sysdev.id); 42 if (!ret) 43 kobject_uevent(&dev->kobj, KOBJ_OFFLINE); 44 break; 45 case '1': 46 ret = cpu_up(cpu->sysdev.id); 47 if (!ret) 48 kobject_uevent(&dev->kobj, KOBJ_ONLINE); 49 break; 50 default: 51 ret = -EINVAL; 52 } 53 cpu_hotplug_driver_unlock(); 54 55 if (ret >= 0) 56 ret = count; 57 return ret; 58 } 59 static SYSDEV_ATTR(online, 0644, show_online, store_online); 60 61 static void __cpuinit register_cpu_control(struct cpu *cpu) 62 { 63 sysdev_create_file(&cpu->sysdev, &attr_online); 64 } 65 void unregister_cpu(struct cpu *cpu) 66 { 67 int logical_cpu = cpu->sysdev.id; 68 69 unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu)); 70 71 sysdev_remove_file(&cpu->sysdev, &attr_online); 72 73 sysdev_unregister(&cpu->sysdev); 74 per_cpu(cpu_sys_devices, logical_cpu) = NULL; 75 return; 76 } 77 78 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE 79 static ssize_t cpu_probe_store(struct class *class, const char *buf, 80 size_t count) 81 { 82 return arch_cpu_probe(buf, count); 83 } 84 85 static ssize_t cpu_release_store(struct class *class, const char *buf, 86 size_t count) 87 { 88 return arch_cpu_release(buf, count); 89 } 90 91 static CLASS_ATTR(probe, S_IWUSR, NULL, cpu_probe_store); 92 static CLASS_ATTR(release, S_IWUSR, NULL, cpu_release_store); 93 94 int __init cpu_probe_release_init(void) 95 { 96 int rc; 97 98 rc = sysfs_create_file(&cpu_sysdev_class.kset.kobj, 99 &class_attr_probe.attr); 100 if (!rc) 101 rc = sysfs_create_file(&cpu_sysdev_class.kset.kobj, 102 &class_attr_release.attr); 103 104 return rc; 105 } 106 device_initcall(cpu_probe_release_init); 107 #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */ 108 109 #else /* ... !CONFIG_HOTPLUG_CPU */ 110 static inline void register_cpu_control(struct cpu *cpu) 111 { 112 } 113 #endif /* CONFIG_HOTPLUG_CPU */ 114 115 #ifdef CONFIG_KEXEC 116 #include <linux/kexec.h> 117 118 static ssize_t show_crash_notes(struct sys_device *dev, struct sysdev_attribute *attr, 119 char *buf) 120 { 121 struct cpu *cpu = container_of(dev, struct cpu, sysdev); 122 ssize_t rc; 123 unsigned long long addr; 124 int cpunum; 125 126 cpunum = cpu->sysdev.id; 127 128 /* 129 * Might be reading other cpu's data based on which cpu read thread 130 * has been scheduled. But cpu data (memory) is allocated once during 131 * boot up and this data does not change there after. Hence this 132 * operation should be safe. No locking required. 133 */ 134 addr = __pa(per_cpu_ptr(crash_notes, cpunum)); 135 rc = sprintf(buf, "%Lx\n", addr); 136 return rc; 137 } 138 static SYSDEV_ATTR(crash_notes, 0400, show_crash_notes, NULL); 139 #endif 140 141 /* 142 * Print cpu online, possible, present, and system maps 143 */ 144 static ssize_t print_cpus_map(char *buf, const struct cpumask *map) 145 { 146 int n = cpulist_scnprintf(buf, PAGE_SIZE-2, map); 147 148 buf[n++] = '\n'; 149 buf[n] = '\0'; 150 return n; 151 } 152 153 #define print_cpus_func(type) \ 154 static ssize_t print_cpus_##type(struct sysdev_class *class, char *buf) \ 155 { \ 156 return print_cpus_map(buf, cpu_##type##_mask); \ 157 } \ 158 static struct sysdev_class_attribute attr_##type##_map = \ 159 _SYSDEV_CLASS_ATTR(type, 0444, print_cpus_##type, NULL) 160 161 print_cpus_func(online); 162 print_cpus_func(possible); 163 print_cpus_func(present); 164 165 /* 166 * Print values for NR_CPUS and offlined cpus 167 */ 168 static ssize_t print_cpus_kernel_max(struct sysdev_class *class, char *buf) 169 { 170 int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1); 171 return n; 172 } 173 static SYSDEV_CLASS_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL); 174 175 /* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */ 176 unsigned int total_cpus; 177 178 static ssize_t print_cpus_offline(struct sysdev_class *class, char *buf) 179 { 180 int n = 0, len = PAGE_SIZE-2; 181 cpumask_var_t offline; 182 183 /* display offline cpus < nr_cpu_ids */ 184 if (!alloc_cpumask_var(&offline, GFP_KERNEL)) 185 return -ENOMEM; 186 cpumask_complement(offline, cpu_online_mask); 187 n = cpulist_scnprintf(buf, len, offline); 188 free_cpumask_var(offline); 189 190 /* display offline cpus >= nr_cpu_ids */ 191 if (total_cpus && nr_cpu_ids < total_cpus) { 192 if (n && n < len) 193 buf[n++] = ','; 194 195 if (nr_cpu_ids == total_cpus-1) 196 n += snprintf(&buf[n], len - n, "%d", nr_cpu_ids); 197 else 198 n += snprintf(&buf[n], len - n, "%d-%d", 199 nr_cpu_ids, total_cpus-1); 200 } 201 202 n += snprintf(&buf[n], len - n, "\n"); 203 return n; 204 } 205 static SYSDEV_CLASS_ATTR(offline, 0444, print_cpus_offline, NULL); 206 207 static struct sysdev_class_attribute *cpu_state_attr[] = { 208 &attr_online_map, 209 &attr_possible_map, 210 &attr_present_map, 211 &attr_kernel_max, 212 &attr_offline, 213 }; 214 215 static int cpu_states_init(void) 216 { 217 int i; 218 int err = 0; 219 220 for (i = 0; i < ARRAY_SIZE(cpu_state_attr); i++) { 221 int ret; 222 ret = sysdev_class_create_file(&cpu_sysdev_class, 223 cpu_state_attr[i]); 224 if (!err) 225 err = ret; 226 } 227 return err; 228 } 229 230 /* 231 * register_cpu - Setup a sysfs device for a CPU. 232 * @cpu - cpu->hotpluggable field set to 1 will generate a control file in 233 * sysfs for this CPU. 234 * @num - CPU number to use when creating the device. 235 * 236 * Initialize and register the CPU device. 237 */ 238 int __cpuinit register_cpu(struct cpu *cpu, int num) 239 { 240 int error; 241 cpu->node_id = cpu_to_node(num); 242 cpu->sysdev.id = num; 243 cpu->sysdev.cls = &cpu_sysdev_class; 244 245 error = sysdev_register(&cpu->sysdev); 246 247 if (!error && cpu->hotpluggable) 248 register_cpu_control(cpu); 249 if (!error) 250 per_cpu(cpu_sys_devices, num) = &cpu->sysdev; 251 if (!error) 252 register_cpu_under_node(num, cpu_to_node(num)); 253 254 #ifdef CONFIG_KEXEC 255 if (!error) 256 error = sysdev_create_file(&cpu->sysdev, &attr_crash_notes); 257 #endif 258 return error; 259 } 260 261 struct sys_device *get_cpu_sysdev(unsigned cpu) 262 { 263 if (cpu < nr_cpu_ids && cpu_possible(cpu)) 264 return per_cpu(cpu_sys_devices, cpu); 265 else 266 return NULL; 267 } 268 EXPORT_SYMBOL_GPL(get_cpu_sysdev); 269 270 int __init cpu_dev_init(void) 271 { 272 int err; 273 274 err = sysdev_class_register(&cpu_sysdev_class); 275 if (!err) 276 err = cpu_states_init(); 277 278 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) 279 if (!err) 280 err = sched_create_sysfs_power_savings_entries(&cpu_sysdev_class); 281 #endif 282 283 return err; 284 } 285