sysfs: Add crash_notes_size to export percpu note size
[deliverable/linux.git] / drivers / base / cpu.c
CommitLineData
1da177e4 1/*
8a25a2fd 2 * CPU subsystem support
1da177e4
LT
3 */
4
024f7846 5#include <linux/kernel.h>
1da177e4
LT
6#include <linux/module.h>
7#include <linux/init.h>
f6a57033 8#include <linux/sched.h>
1da177e4
LT
9#include <linux/cpu.h>
10#include <linux/topology.h>
11#include <linux/device.h>
76b67ed9 12#include <linux/node.h>
5a0e3ad6 13#include <linux/gfp.h>
fad12ac8 14#include <linux/slab.h>
9f13a1fd 15#include <linux/percpu.h>
1da177e4 16
a1bdc7aa 17#include "base.h"
1da177e4 18
8a25a2fd 19struct bus_type cpu_subsys = {
af5ca3f4 20 .name = "cpu",
8a25a2fd 21 .dev_name = "cpu",
1da177e4 22};
8a25a2fd 23EXPORT_SYMBOL_GPL(cpu_subsys);
1da177e4 24
8a25a2fd 25static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
ad74557a 26
1da177e4 27#ifdef CONFIG_HOTPLUG_CPU
8a25a2fd
KS
28static ssize_t show_online(struct device *dev,
29 struct device_attribute *attr,
4a0b2b4d 30 char *buf)
1da177e4 31{
8a25a2fd 32 struct cpu *cpu = container_of(dev, struct cpu, dev);
1da177e4 33
8a25a2fd 34 return sprintf(buf, "%u\n", !!cpu_online(cpu->dev.id));
1da177e4
LT
35}
36
8a25a2fd
KS
37static ssize_t __ref store_online(struct device *dev,
38 struct device_attribute *attr,
39 const char *buf, size_t count)
1da177e4 40{
8a25a2fd 41 struct cpu *cpu = container_of(dev, struct cpu, dev);
1da177e4
LT
42 ssize_t ret;
43
51badebd 44 cpu_hotplug_driver_lock();
1da177e4
LT
45 switch (buf[0]) {
46 case '0':
8a25a2fd 47 ret = cpu_down(cpu->dev.id);
1da177e4 48 if (!ret)
312c004d 49 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
1da177e4
LT
50 break;
51 case '1':
8a25a2fd 52 ret = cpu_up(cpu->dev.id);
fb69c390 53 if (!ret)
312c004d 54 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
1da177e4
LT
55 break;
56 default:
57 ret = -EINVAL;
58 }
51badebd 59 cpu_hotplug_driver_unlock();
1da177e4
LT
60
61 if (ret >= 0)
62 ret = count;
63 return ret;
64}
8a25a2fd 65static DEVICE_ATTR(online, 0644, show_online, store_online);
1da177e4 66
6c847402 67static void __cpuinit register_cpu_control(struct cpu *cpu)
1da177e4 68{
8a25a2fd 69 device_create_file(&cpu->dev, &dev_attr_online);
1da177e4 70}
76b67ed9 71void unregister_cpu(struct cpu *cpu)
1da177e4 72{
8a25a2fd 73 int logical_cpu = cpu->dev.id;
1da177e4 74
76b67ed9
KH
75 unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));
76
8a25a2fd 77 device_remove_file(&cpu->dev, &dev_attr_online);
1da177e4 78
8a25a2fd 79 device_unregister(&cpu->dev);
e37d05da 80 per_cpu(cpu_sys_devices, logical_cpu) = NULL;
1da177e4
LT
81 return;
82}
12633e80
NF
83
84#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
8a25a2fd
KS
85static ssize_t cpu_probe_store(struct device *dev,
86 struct device_attribute *attr,
67fc233f 87 const char *buf,
12633e80
NF
88 size_t count)
89{
90 return arch_cpu_probe(buf, count);
91}
92
8a25a2fd
KS
93static ssize_t cpu_release_store(struct device *dev,
94 struct device_attribute *attr,
67fc233f 95 const char *buf,
12633e80
NF
96 size_t count)
97{
98 return arch_cpu_release(buf, count);
99}
100
8a25a2fd
KS
101static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
102static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
12633e80
NF
103#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
104
1da177e4
LT
105#else /* ... !CONFIG_HOTPLUG_CPU */
106static inline void register_cpu_control(struct cpu *cpu)
107{
108}
109#endif /* CONFIG_HOTPLUG_CPU */
110
51be5606
VG
111#ifdef CONFIG_KEXEC
112#include <linux/kexec.h>
113
8a25a2fd 114static ssize_t show_crash_notes(struct device *dev, struct device_attribute *attr,
4a0b2b4d 115 char *buf)
51be5606 116{
8a25a2fd 117 struct cpu *cpu = container_of(dev, struct cpu, dev);
51be5606
VG
118 ssize_t rc;
119 unsigned long long addr;
120 int cpunum;
121
8a25a2fd 122 cpunum = cpu->dev.id;
51be5606
VG
123
124 /*
125 * Might be reading other cpu's data based on which cpu read thread
126 * has been scheduled. But cpu data (memory) is allocated once during
127 * boot up and this data does not change there after. Hence this
128 * operation should be safe. No locking required.
129 */
3b034b0d 130 addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
51be5606 131 rc = sprintf(buf, "%Lx\n", addr);
51be5606
VG
132 return rc;
133}
8a25a2fd 134static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
eca4549f
ZY
135
136static ssize_t show_crash_notes_size(struct device *dev,
137 struct device_attribute *attr,
138 char *buf)
139{
140 ssize_t rc;
141
142 rc = sprintf(buf, "%lu\n", sizeof(note_buf_t));
143 return rc;
144}
145static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);
51be5606
VG
146#endif
147
9d1fe323
MT
148/*
149 * Print cpu online, possible, present, and system maps
150 */
265d2e2e
AK
151
152struct cpu_attr {
8a25a2fd 153 struct device_attribute attr;
265d2e2e
AK
154 const struct cpumask *const * const map;
155};
156
8a25a2fd
KS
157static ssize_t show_cpus_attr(struct device *dev,
158 struct device_attribute *attr,
265d2e2e 159 char *buf)
9d1fe323 160{
265d2e2e
AK
161 struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr);
162 int n = cpulist_scnprintf(buf, PAGE_SIZE-2, *(ca->map));
9d1fe323
MT
163
164 buf[n++] = '\n';
165 buf[n] = '\0';
166 return n;
167}
168
8a25a2fd
KS
169#define _CPU_ATTR(name, map) \
170 { __ATTR(name, 0444, show_cpus_attr, NULL), map }
9d1fe323 171
8a25a2fd 172/* Keep in sync with cpu_subsys_attrs */
265d2e2e
AK
173static struct cpu_attr cpu_attrs[] = {
174 _CPU_ATTR(online, &cpu_online_mask),
175 _CPU_ATTR(possible, &cpu_possible_mask),
176 _CPU_ATTR(present, &cpu_present_mask),
177};
9d1fe323 178
e057d7ae
MT
179/*
180 * Print values for NR_CPUS and offlined cpus
181 */
8a25a2fd
KS
182static ssize_t print_cpus_kernel_max(struct device *dev,
183 struct device_attribute *attr, char *buf)
e057d7ae 184{
8fd2d2d5 185 int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1);
e057d7ae
MT
186 return n;
187}
8a25a2fd 188static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
e057d7ae
MT
189
190/* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
191unsigned int total_cpus;
192
8a25a2fd
KS
193static ssize_t print_cpus_offline(struct device *dev,
194 struct device_attribute *attr, char *buf)
e057d7ae
MT
195{
196 int n = 0, len = PAGE_SIZE-2;
197 cpumask_var_t offline;
198
199 /* display offline cpus < nr_cpu_ids */
200 if (!alloc_cpumask_var(&offline, GFP_KERNEL))
201 return -ENOMEM;
cdc6e3d3 202 cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask);
e057d7ae
MT
203 n = cpulist_scnprintf(buf, len, offline);
204 free_cpumask_var(offline);
205
206 /* display offline cpus >= nr_cpu_ids */
207 if (total_cpus && nr_cpu_ids < total_cpus) {
208 if (n && n < len)
209 buf[n++] = ',';
210
211 if (nr_cpu_ids == total_cpus-1)
212 n += snprintf(&buf[n], len - n, "%d", nr_cpu_ids);
213 else
214 n += snprintf(&buf[n], len - n, "%d-%d",
215 nr_cpu_ids, total_cpus-1);
216 }
217
218 n += snprintf(&buf[n], len - n, "\n");
219 return n;
220}
8a25a2fd 221static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
e057d7ae 222
2885e25c
GKH
223static void cpu_device_release(struct device *dev)
224{
225 /*
226 * This is an empty function to prevent the driver core from spitting a
227 * warning at us. Yes, I know this is directly opposite of what the
228 * documentation for the driver core and kobjects say, and the author
229 * of this code has already been publically ridiculed for doing
230 * something as foolish as this. However, at this point in time, it is
231 * the only way to handle the issue of statically allocated cpu
232 * devices. The different architectures will have their cpu device
233 * code reworked to properly handle this in the near future, so this
234 * function will then be changed to correctly free up the memory held
235 * by the cpu device.
236 *
237 * Never copy this way of doing things, or you too will be made fun of
30a4840a 238 * on the linux-kernel list, you have been warned.
2885e25c
GKH
239 */
240}
241
1da177e4 242/*
405ae7d3 243 * register_cpu - Setup a sysfs device for a CPU.
72486f1f
SS
244 * @cpu - cpu->hotpluggable field set to 1 will generate a control file in
245 * sysfs for this CPU.
1da177e4
LT
246 * @num - CPU number to use when creating the device.
247 *
248 * Initialize and register the CPU device.
249 */
33b5f31b 250int __cpuinit register_cpu(struct cpu *cpu, int num)
1da177e4
LT
251{
252 int error;
76b67ed9 253
8a25a2fd 254 cpu->node_id = cpu_to_node(num);
29bb5d4f 255 memset(&cpu->dev, 0x00, sizeof(struct device));
8a25a2fd
KS
256 cpu->dev.id = num;
257 cpu->dev.bus = &cpu_subsys;
2885e25c 258 cpu->dev.release = cpu_device_release;
fad12ac8
TR
259#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
260 cpu->dev.bus->uevent = arch_cpu_uevent;
261#endif
8a25a2fd 262 error = device_register(&cpu->dev);
72486f1f 263 if (!error && cpu->hotpluggable)
1da177e4 264 register_cpu_control(cpu);
ad74557a 265 if (!error)
8a25a2fd 266 per_cpu(cpu_sys_devices, num) = &cpu->dev;
76b67ed9
KH
267 if (!error)
268 register_cpu_under_node(num, cpu_to_node(num));
51be5606
VG
269
270#ifdef CONFIG_KEXEC
271 if (!error)
8a25a2fd 272 error = device_create_file(&cpu->dev, &dev_attr_crash_notes);
eca4549f
ZY
273 if (!error)
274 error = device_create_file(&cpu->dev,
275 &dev_attr_crash_notes_size);
51be5606 276#endif
1da177e4
LT
277 return error;
278}
279
8a25a2fd 280struct device *get_cpu_device(unsigned cpu)
ad74557a 281{
e37d05da
MT
282 if (cpu < nr_cpu_ids && cpu_possible(cpu))
283 return per_cpu(cpu_sys_devices, cpu);
ad74557a
AR
284 else
285 return NULL;
286}
8a25a2fd
KS
287EXPORT_SYMBOL_GPL(get_cpu_device);
288
fad12ac8
TR
289#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
290static DEVICE_ATTR(modalias, 0444, arch_print_cpu_modalias, NULL);
291#endif
292
8a25a2fd
KS
293static struct attribute *cpu_root_attrs[] = {
294#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
295 &dev_attr_probe.attr,
296 &dev_attr_release.attr,
297#endif
298 &cpu_attrs[0].attr.attr,
299 &cpu_attrs[1].attr.attr,
300 &cpu_attrs[2].attr.attr,
301 &dev_attr_kernel_max.attr,
302 &dev_attr_offline.attr,
fad12ac8
TR
303#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
304 &dev_attr_modalias.attr,
305#endif
8a25a2fd
KS
306 NULL
307};
308
309static struct attribute_group cpu_root_attr_group = {
310 .attrs = cpu_root_attrs,
311};
312
313static const struct attribute_group *cpu_root_attr_groups[] = {
314 &cpu_root_attr_group,
315 NULL,
316};
1da177e4 317
2987557f
JT
318bool cpu_is_hotpluggable(unsigned cpu)
319{
7affca35
LT
320 struct device *dev = get_cpu_device(cpu);
321 return dev && container_of(dev, struct cpu, dev)->hotpluggable;
2987557f
JT
322}
323EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
324
9f13a1fd
BH
325#ifdef CONFIG_GENERIC_CPU_DEVICES
326static DEFINE_PER_CPU(struct cpu, cpu_devices);
327#endif
328
329static void __init cpu_dev_register_generic(void)
330{
331#ifdef CONFIG_GENERIC_CPU_DEVICES
332 int i;
333
334 for_each_possible_cpu(i) {
335 if (register_cpu(&per_cpu(cpu_devices, i), i))
336 panic("Failed to register CPU device");
337 }
338#endif
339}
340
024f7846 341void __init cpu_dev_init(void)
1da177e4 342{
024f7846
BH
343 if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
344 panic("Failed to register CPU subsystem");
8a25a2fd 345
9f13a1fd 346 cpu_dev_register_generic();
1da177e4 347}
This page took 1.04637 seconds and 5 git commands to generate.