1 // SPDX-License-Identifier: GPL-2.0
3  * CPU subsystem support
10 #include <linux/cpu.h>
38 static void change_cpu_under_node(struct cpu *cpu,  in change_cpu_under_node()  argument
41 	int cpuid = cpu->dev.id;  in change_cpu_under_node()
44 	cpu->node_id = to_nid;  in change_cpu_under_node()
49 	struct cpu *cpu = container_of(dev, struct cpu, dev);  in cpu_subsys_online()  local
50 	int cpuid = dev->id;  in cpu_subsys_online()
56 		return -ENODEV;  in cpu_subsys_online()
60 	 * When hot adding memory to memoryless node and enabling a cpu  in cpu_subsys_online()
61 	 * on the node, node number of the cpu may internally change.  in cpu_subsys_online()
65 		change_cpu_under_node(cpu, from_nid, to_nid);  in cpu_subsys_online()
75 void unregister_cpu(struct cpu *cpu)  in unregister_cpu()  argument
77 	int logical_cpu = cpu->dev.id;  in unregister_cpu()
81 	device_unregister(&cpu->dev);  in unregister_cpu()
124 static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
129 	.name = "cpu",
130 	.dev_name = "cpu",
146 	struct cpu *cpu = container_of(dev, struct cpu, dev);  in crash_notes_show()  local
147 	unsigned long long addr;  in crash_notes_show()  local
150 	cpunum = cpu->dev.id;  in crash_notes_show()
153 	 * Might be reading other cpu's data based on which cpu read thread  in crash_notes_show()
154 	 * has been scheduled. But cpu data (memory) is allocated once during  in crash_notes_show()
158 	addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));  in crash_notes_show()
160 	return sysfs_emit(buf, "%llx\n", addr);  in crash_notes_show()
198  * Print cpu online, possible, present, and system maps
212 	return cpumap_print_to_pagebuf(true, buf, ca->map);  in show_cpus_attr()
231 	return sysfs_emit(buf, "%d\n", NR_CPUS - 1);  in print_cpus_kernel_max()
235 /* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
246 		return -ENOMEM;  in print_cpus_offline()
255 		if (nr_cpu_ids == total_cpus-1)  in print_cpus_offline()
258 			len += sysfs_emit_at(buf, len, "%u-%d",  in print_cpus_offline()
259 					     nr_cpu_ids, total_cpus - 1);  in print_cpus_offline()
275 		return -ENOMEM;  in print_cpus_isolated()
304 	 * the only way to handle the issue of statically allocated cpu  in cpu_device_release()
305 	 * devices.  The different architectures will have their cpu device  in cpu_device_release()
308 	 * by the cpu device.  in cpu_device_release()
311 	 * on the linux-kernel list, you have been warned.  in cpu_device_release()
324 			     "cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",  in print_cpu_modalias()
330 				WARN(1, "CPU features overflow page\n");  in print_cpu_modalias()
352  * register_cpu - Setup a sysfs device for a CPU.
353  * @cpu - cpu->hotpluggable field set to 1 will generate a control file in
354  *	  sysfs for this CPU.
355  * @num - CPU number to use when creating the device.
357  * Initialize and register the CPU device.
359 int register_cpu(struct cpu *cpu, int num)  in register_cpu()  argument
363 	cpu->node_id = cpu_to_node(num);  in register_cpu()
364 	memset(&cpu->dev, 0x00, sizeof(struct device));  in register_cpu()
365 	cpu->dev.id = num;  in register_cpu()
366 	cpu->dev.bus = &cpu_subsys;  in register_cpu()
367 	cpu->dev.release = cpu_device_release;  in register_cpu()
368 	cpu->dev.offline_disabled = !cpu->hotpluggable;  in register_cpu()
369 	cpu->dev.offline = !cpu_online(num);  in register_cpu()
370 	cpu->dev.of_node = of_get_cpu_node(num, NULL);  in register_cpu()
372 	cpu->dev.bus->uevent = cpu_uevent;  in register_cpu()
374 	cpu->dev.groups = common_cpu_attr_groups;  in register_cpu()
375 	if (cpu->hotpluggable)  in register_cpu()
376 		cpu->dev.groups = hotplugable_cpu_attr_groups;  in register_cpu()
377 	error = device_register(&cpu->dev);  in register_cpu()
379 		put_device(&cpu->dev);  in register_cpu()
383 	per_cpu(cpu_sys_devices, num) = &cpu->dev;  in register_cpu()
385 	dev_pm_qos_expose_latency_limit(&cpu->dev,  in register_cpu()
391 struct device *get_cpu_device(unsigned cpu)  in get_cpu_device()  argument
393 	if (cpu < nr_cpu_ids && cpu_possible(cpu))  in get_cpu_device()
394 		return per_cpu(cpu_sys_devices, cpu);  in get_cpu_device()
412 	int retval = -ENODEV;  in __cpu_device_create()
416 		retval = -ENOMEM;  in __cpu_device_create()
421 	dev->parent = parent;  in __cpu_device_create()
422 	dev->groups = groups;  in __cpu_device_create()
423 	dev->release = device_create_release;  in __cpu_device_create()
427 	retval = kobject_set_name_vargs(&dev->kobj, fmt, args);  in __cpu_device_create()
489 bool cpu_is_hotpluggable(unsigned cpu)  in cpu_is_hotpluggable()  argument
491 	struct device *dev = get_cpu_device(cpu);  in cpu_is_hotpluggable()
492 	return dev && container_of(dev, struct cpu, dev)->hotpluggable;  in cpu_is_hotpluggable()
497 static DEFINE_PER_CPU(struct cpu, cpu_devices);
507 			panic("Failed to register CPU device");  in cpu_dev_register_generic()
599 	if (sysfs_create_group(&cpu_subsys.dev_root->kobj,  in cpu_register_vulnerabilities()
601 		pr_err("Unable to register CPU vulnerabilities\n");  in cpu_register_vulnerabilities()
611 		panic("Failed to register CPU subsystem");  in cpu_dev_init()