Add a sysfs interface so we can actually see in which state the cpus are in.
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
kernel/cpu.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 98 insertions(+)
Index: b/kernel/cpu.c
===================================================================
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -56,6 +56,7 @@ struct cpuhp_step {
bool skip_onerr;
};
+static DEFINE_MUTEX(cpuhp_state_mutex);
static struct cpuhp_step cpuhp_bp_states[];
static struct cpuhp_step cpuhp_ap_states[];
@@ -955,6 +956,103 @@ static struct cpuhp_step cpuhp_ap_states
},
};
+static bool cpuhp_is_ap_state(enum cpuhp_state state)
+{
+ return (state > CPUHP_AP_OFFLINE && state < CPUHP_AP_ONLINE);
+}
+
+static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state)
+{
+ struct cpuhp_step *sp;
+
+ sp = cpuhp_is_ap_state(state) ? cpuhp_ap_states : cpuhp_bp_states;
+ return sp + state;
+}
+
+#if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU)
+static ssize_t show_cpuhp_state(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
+
+ return sprintf(buf, "%d\n", st->state);
+}
+static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL);
+
+static ssize_t show_cpuhp_target(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
+
+ return sprintf(buf, "%d\n", st->target);
+}
+static DEVICE_ATTR(target, 0444, show_cpuhp_target, NULL);
+
+static struct attribute *cpuhp_cpu_attrs[] = {
+ &dev_attr_state.attr,
+ &dev_attr_target.attr,
+ NULL
+};
+
+static struct attribute_group cpuhp_cpu_attr_group = {
+ .attrs = cpuhp_cpu_attrs,
+ .name = "hotplug",
+ NULL
+};
+
+static ssize_t show_cpuhp_states(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ ssize_t cur, res = 0;
+ int i;
+
+ mutex_lock(&cpuhp_state_mutex);
+ for (i = 0; i <= CPUHP_ONLINE; i++) {
+ struct cpuhp_step *sp = cpuhp_get_step(i);
+
+ if (sp->name) {
+ cur = sprintf(buf, "%3d: %s\n", i, sp->name);
+ buf += cur;
+ res += cur;
+ }
+ }
+ mutex_unlock(&cpuhp_state_mutex);
+ return res;
+}
+static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL);
+
+static struct attribute *cpuhp_cpu_root_attrs[] = {
+ &dev_attr_states.attr,
+ NULL
+};
+
+static struct attribute_group cpuhp_cpu_root_attr_group = {
+ .attrs = cpuhp_cpu_root_attrs,
+ .name = "hotplug",
+ NULL
+};
+
+static int __init cpuhp_sysfs_init(void)
+{
+ int cpu, ret;
+
+ ret = sysfs_create_group(&cpu_subsys.dev_root->kobj,
+ &cpuhp_cpu_root_attr_group);
+ if (ret)
+ return ret;
+
+ for_each_possible_cpu(cpu) {
+ struct device *dev = get_cpu_device(cpu);
+
+ ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group);
+ if (ret)
+ return ret;
+ }
+ return 0;
+}
+device_initcall(cpuhp_sysfs_init);
+#endif
+
/*
* cpu_bit_bitmap[] is a special, "compressed" data structure that
* represents all NR_CPUS bits binary values of 1<<nr.
