cpumask: add show cpu map functions

  * Add cpu_sysdev_class functions to display the following maps
    with cpulist_scnprintf().

	cpu_online_map
	cpu_present_map
	cpu_possible_map

  * Small change to include/linux/sysdev.h to allow the attribute
    name and label to be different (to avoid collision with the
    "attr_online" entry for bringing cpus on- and off-line.)

Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 48 insertions, 0 deletions

diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 499b003f927..2c76afff3b1 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -103,6 +103,51 @@ static SYSDEV_ATTR(crash_notes, 0400, show_crash_notes, NULL);
 #endif
 
 /*
+ * Print cpu online, possible, present, and system maps
+ */
+static ssize_t print_cpus_map(char *buf, cpumask_t *map)
+{
+	int n = cpulist_scnprintf(buf, PAGE_SIZE-2, *map);
+
+	buf[n++] = '\n';
+	buf[n] = '\0';
+	return n;
+}
+
+#define	print_cpus_func(type) \
+static ssize_t print_cpus_##type(struct sysdev_class *class, char *buf)	\
+{									\
+	return print_cpus_map(buf, &cpu_##type##_map);			\
+}									\
+struct sysdev_class_attribute attr_##type##_map = 			\
+	_SYSDEV_CLASS_ATTR(type, 0444, print_cpus_##type, NULL)
+
+print_cpus_func(online);
+print_cpus_func(possible);
+print_cpus_func(present);
+
+struct sysdev_class_attribute *cpu_state_attr[] = {
+	&attr_online_map,
+	&attr_possible_map,
+	&attr_present_map,
+};
+
+static int cpu_states_init(void)
+{
+	int i;
+	int err = 0;
+
+	for (i = 0;  i < ARRAY_SIZE(cpu_state_attr); i++) {
+		int ret;
+		ret = sysdev_class_create_file(&cpu_sysdev_class,
+						cpu_state_attr[i]);
+		if (!err)
+			err = ret;
+	}
+	return err;
+}
+
+/*
  * register_cpu - Setup a sysfs device for a CPU.
  * @cpu - cpu->hotpluggable field set to 1 will generate a control file in
  *	  sysfs for this CPU.
@@ -147,6 +192,9 @@ int __init cpu_dev_init(void)
 	int err;
 
 	err = sysdev_class_register(&cpu_sysdev_class);
+	if (!err)
+		err = cpu_states_init();
+
 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
 	if (!err)
 		err = sched_create_sysfs_power_savings_entries(&cpu_sysdev_class);