Root/drivers/base/topology.c

1/*
2 * driver/base/topology.c - Populate sysfs with cpu topology information
3 *
4 * Written by: Zhang Yanmin, Intel Corporation
5 *
6 * Copyright (C) 2006, Intel Corp.
7 *
8 * All rights reserved.
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
18 * NON INFRINGEMENT. See the GNU General Public License for more
19 * details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 *
25 */
26#include <linux/init.h>
27#include <linux/mm.h>
28#include <linux/cpu.h>
29#include <linux/module.h>
30#include <linux/hardirq.h>
31#include <linux/topology.h>
32
33#define define_one_ro_named(_name, _func) \
34    static DEVICE_ATTR(_name, 0444, _func, NULL)
35
36#define define_one_ro(_name) \
37    static DEVICE_ATTR(_name, 0444, show_##_name, NULL)
38
39#define define_id_show_func(name) \
40static ssize_t show_##name(struct device *dev, \
41        struct device_attribute *attr, char *buf) \
42{ \
43    unsigned int cpu = dev->id; \
44    return sprintf(buf, "%d\n", topology_##name(cpu)); \
45}
46
47#if defined(topology_thread_cpumask) || defined(topology_core_cpumask) || \
48    defined(topology_book_cpumask)
49static ssize_t show_cpumap(int type, const struct cpumask *mask, char *buf)
50{
51    ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf;
52    int n = 0;
53
54    if (len > 1) {
55        n = type?
56            cpulist_scnprintf(buf, len-2, mask) :
57            cpumask_scnprintf(buf, len-2, mask);
58        buf[n++] = '\n';
59        buf[n] = '\0';
60    }
61    return n;
62}
63#endif
64
65#ifdef arch_provides_topology_pointers
66#define define_siblings_show_map(name) \
67static ssize_t show_##name(struct device *dev, \
68               struct device_attribute *attr, char *buf) \
69{ \
70    unsigned int cpu = dev->id; \
71    return show_cpumap(0, topology_##name(cpu), buf); \
72}
73
74#define define_siblings_show_list(name) \
75static ssize_t show_##name##_list(struct device *dev, \
76                  struct device_attribute *attr, \
77                  char *buf) \
78{ \
79    unsigned int cpu = dev->id; \
80    return show_cpumap(1, topology_##name(cpu), buf); \
81}
82
83#else
84#define define_siblings_show_map(name) \
85static ssize_t show_##name(struct device *dev, \
86               struct device_attribute *attr, char *buf) \
87{ \
88    return show_cpumap(0, topology_##name(dev->id), buf); \
89}
90
91#define define_siblings_show_list(name) \
92static ssize_t show_##name##_list(struct device *dev, \
93                  struct device_attribute *attr, \
94                  char *buf) \
95{ \
96    return show_cpumap(1, topology_##name(dev->id), buf); \
97}
98#endif
99
100#define define_siblings_show_func(name) \
101    define_siblings_show_map(name); define_siblings_show_list(name)
102
103define_id_show_func(physical_package_id);
104define_one_ro(physical_package_id);
105
106define_id_show_func(core_id);
107define_one_ro(core_id);
108
109define_siblings_show_func(thread_cpumask);
110define_one_ro_named(thread_siblings, show_thread_cpumask);
111define_one_ro_named(thread_siblings_list, show_thread_cpumask_list);
112
113define_siblings_show_func(core_cpumask);
114define_one_ro_named(core_siblings, show_core_cpumask);
115define_one_ro_named(core_siblings_list, show_core_cpumask_list);
116
117#ifdef CONFIG_SCHED_BOOK
118define_id_show_func(book_id);
119define_one_ro(book_id);
120define_siblings_show_func(book_cpumask);
121define_one_ro_named(book_siblings, show_book_cpumask);
122define_one_ro_named(book_siblings_list, show_book_cpumask_list);
123#endif
124
125static struct attribute *default_attrs[] = {
126    &dev_attr_physical_package_id.attr,
127    &dev_attr_core_id.attr,
128    &dev_attr_thread_siblings.attr,
129    &dev_attr_thread_siblings_list.attr,
130    &dev_attr_core_siblings.attr,
131    &dev_attr_core_siblings_list.attr,
132#ifdef CONFIG_SCHED_BOOK
133    &dev_attr_book_id.attr,
134    &dev_attr_book_siblings.attr,
135    &dev_attr_book_siblings_list.attr,
136#endif
137    NULL
138};
139
140static struct attribute_group topology_attr_group = {
141    .attrs = default_attrs,
142    .name = "topology"
143};
144
145/* Add/Remove cpu_topology interface for CPU device */
146static int __cpuinit topology_add_dev(unsigned int cpu)
147{
148    struct device *dev = get_cpu_device(cpu);
149
150    return sysfs_create_group(&dev->kobj, &topology_attr_group);
151}
152
153static void __cpuinit topology_remove_dev(unsigned int cpu)
154{
155    struct device *dev = get_cpu_device(cpu);
156
157    sysfs_remove_group(&dev->kobj, &topology_attr_group);
158}
159
160static int __cpuinit topology_cpu_callback(struct notifier_block *nfb,
161                       unsigned long action, void *hcpu)
162{
163    unsigned int cpu = (unsigned long)hcpu;
164    int rc = 0;
165
166    switch (action) {
167    case CPU_UP_PREPARE:
168    case CPU_UP_PREPARE_FROZEN:
169        rc = topology_add_dev(cpu);
170        break;
171    case CPU_UP_CANCELED:
172    case CPU_UP_CANCELED_FROZEN:
173    case CPU_DEAD:
174    case CPU_DEAD_FROZEN:
175        topology_remove_dev(cpu);
176        break;
177    }
178    return notifier_from_errno(rc);
179}
180
181static int __cpuinit topology_sysfs_init(void)
182{
183    int cpu;
184    int rc;
185
186    for_each_online_cpu(cpu) {
187        rc = topology_add_dev(cpu);
188        if (rc)
189            return rc;
190    }
191    hotcpu_notifier(topology_cpu_callback, 0);
192
193    return 0;
194}
195
196device_initcall(topology_sysfs_init);
197

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