s390/topology: add detection of dedicated vs shared CPUs

The topology information returned by STSI 15.x.x contains a flag
if the CPUs of a topology-list are dedicated or shared. Make this
information available if the machine provides topology information.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/processor.h

@@ -21,6 +21,7 @@
 #define CIF_IGNORE_IRQ		5	/* ignore interrupt (for udelay) */
 #define CIF_ENABLED_WAIT	6	/* in enabled wait state */
 #define CIF_MCCK_GUEST		7	/* machine check happening in guest */
+#define CIF_DEDICATED_CPU	8	/* this CPU is dedicated */
 
 #define _CIF_MCCK_PENDING	_BITUL(CIF_MCCK_PENDING)
 #define _CIF_ASCE_PRIMARY	_BITUL(CIF_ASCE_PRIMARY)
@@ -30,6 +31,7 @@
 #define _CIF_IGNORE_IRQ		_BITUL(CIF_IGNORE_IRQ)
 #define _CIF_ENABLED_WAIT	_BITUL(CIF_ENABLED_WAIT)
 #define _CIF_MCCK_GUEST		_BITUL(CIF_MCCK_GUEST)
+#define _CIF_DEDICATED_CPU	_BITUL(CIF_DEDICATED_CPU)
 
 #ifndef __ASSEMBLY__
 

arch/s390/include/asm/sysinfo.h

@@ -156,7 +156,8 @@ static inline unsigned char topology_mnest_limit(void)
 struct topology_core {
 	unsigned char nl;
 	unsigned char reserved0[3];
-	unsigned char :6;
+	unsigned char :5;
+	unsigned char d:1;
 	unsigned char pp:2;
 	unsigned char reserved1;
 	unsigned short origin;

arch/s390/include/asm/topology.h

@@ -16,6 +16,7 @@ struct cpu_topology_s390 {
 	unsigned short book_id;
 	unsigned short drawer_id;
 	unsigned short node_id;
+	unsigned short dedicated : 1;
 	cpumask_t thread_mask;
 	cpumask_t core_mask;
 	cpumask_t book_mask;
@@ -34,6 +35,7 @@ extern cpumask_t cpus_with_topology;
 #define topology_book_cpumask(cpu)	  (&cpu_topology[cpu].book_mask)
 #define topology_drawer_id(cpu)		  (cpu_topology[cpu].drawer_id)
 #define topology_drawer_cpumask(cpu)	  (&cpu_topology[cpu].drawer_mask)
+#define topology_cpu_dedicated(cpu)	  (cpu_topology[cpu].dedicated)
 
 #define mc_capable() 1
 

arch/s390/kernel/smp.c

@@ -800,6 +800,8 @@ void __init smp_detect_cpus(void)
  */
 static void smp_start_secondary(void *cpuvoid)
 {
+	int cpu = smp_processor_id();
+
 	S390_lowcore.last_update_clock = get_tod_clock();
 	S390_lowcore.restart_stack = (unsigned long) restart_stack;
 	S390_lowcore.restart_fn = (unsigned long) do_restart;
@@ -813,8 +815,12 @@ static void smp_start_secondary(void *cpuvoid)
 	init_cpu_timer();
 	vtime_init();
 	pfault_init();
-	notify_cpu_starting(smp_processor_id());
+	notify_cpu_starting(cpu);
-	set_cpu_online(smp_processor_id(), true);
+	if (topology_cpu_dedicated(cpu))
+		set_cpu_flag(CIF_DEDICATED_CPU);
+	else
+		clear_cpu_flag(CIF_DEDICATED_CPU);
+	set_cpu_online(cpu, true);
 	inc_irq_stat(CPU_RST);
 	local_irq_enable();
 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);

arch/s390/kernel/topology.c

@@ -133,6 +133,7 @@ static void add_cpus_to_mask(struct topology_core *tl_core,
 			topo->socket_id = socket->id;
 			topo->core_id = rcore;
 			topo->thread_id = lcpu + i;
+			topo->dedicated = tl_core->d;
 			cpumask_set_cpu(lcpu + i, &drawer->mask);
 			cpumask_set_cpu(lcpu + i, &book->mask);
 			cpumask_set_cpu(lcpu + i, &socket->mask);
@@ -273,6 +274,14 @@ void store_topology(struct sysinfo_15_1_x *info)
 	stsi(info, 15, 1, topology_mnest_limit());
 }
 
+static void __arch_update_dedicated_flag(void *arg)
+{
+	if (topology_cpu_dedicated(smp_processor_id()))
+		set_cpu_flag(CIF_DEDICATED_CPU);
+	else
+		clear_cpu_flag(CIF_DEDICATED_CPU);
+}
+
 static int __arch_update_cpu_topology(void)
 {
 	struct sysinfo_15_1_x *info = tl_info;
@@ -298,6 +307,7 @@ int arch_update_cpu_topology(void)
 	int cpu, rc;
 
 	rc = __arch_update_cpu_topology();
+	on_each_cpu(__arch_update_dedicated_flag, NULL, 0);
 	for_each_online_cpu(cpu) {
 		dev = get_cpu_device(cpu);
 		kobject_uevent(&dev->kobj, KOBJ_CHANGE);
@@ -435,9 +445,39 @@ static struct attribute_group topology_cpu_attr_group = {
 	.attrs = topology_cpu_attrs,
 };
 
+static ssize_t cpu_dedicated_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	int cpu = dev->id;
+	ssize_t count;
+
+	mutex_lock(&smp_cpu_state_mutex);
+	count = sprintf(buf, "%d\n", topology_cpu_dedicated(cpu));
+	mutex_unlock(&smp_cpu_state_mutex);
+	return count;
+}
+static DEVICE_ATTR(dedicated, 0444, cpu_dedicated_show, NULL);
+
+static struct attribute *topology_extra_cpu_attrs[] = {
+	&dev_attr_dedicated.attr,
+	NULL,
+};
+
+static struct attribute_group topology_extra_cpu_attr_group = {
+	.attrs = topology_extra_cpu_attrs,
+};
+
 int topology_cpu_init(struct cpu *cpu)
 {
-	return sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
+	int rc;
+
+	rc = sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
+	if (rc || !MACHINE_HAS_TOPOLOGY)
+		return rc;
+	rc = sysfs_create_group(&cpu->dev.kobj, &topology_extra_cpu_attr_group);
+	if (rc)
+		sysfs_remove_group(&cpu->dev.kobj, &topology_cpu_attr_group);
+	return rc;
 }
 
 static const struct cpumask *cpu_thread_mask(int cpu)
@@ -509,6 +549,7 @@ void __init topology_init_early(void)
 	alloc_masks(info, &drawer_info, 3);
 out:
 	__arch_update_cpu_topology();
+	__arch_update_dedicated_flag(NULL);
 }
 
 static inline int topology_get_mode(int enabled)