text: /*
   *    Copyright IBM Corp. 2007, 2011
   *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
   */
  
  #define KMSG_COMPONENT "cpu"
  #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  
  #include <linux/workqueue.h>
  #include <linux/bootmem.h>
  #include <linux/cpuset.h>
  #include <linux/device.h>
  #include <linux/export.h>
  #include <linux/kernel.h>
  #include <linux/sched.h>
  #include <linux/init.h>
  #include <linux/delay.h>
  #include <linux/cpu.h>
  #include <linux/smp.h>
  #include <linux/mm.h>
  #include <asm/sysinfo.h>
  
  #define PTF_HORIZONTAL	(0UL)
  #define PTF_VERTICAL	(1UL)
  #define PTF_CHECK	(2UL)
  
  struct mask_info {
  	struct mask_info *next;
  	unsigned char id;
  	cpumask_t mask;
  };
  
  static void set_topology_timer(void);
  static void topology_work_fn(struct work_struct *work);
  static struct sysinfo_15_1_x *tl_info;
  
  static int topology_enabled = 1;
  static DECLARE_WORK(topology_work, topology_work_fn);
  
  /* topology_lock protects the socket and book linked lists */
  static DEFINE_SPINLOCK(topology_lock);
  static struct mask_info socket_info;
  static struct mask_info book_info;
  
  struct cpu_topology_s390 cpu_topology[NR_CPUS];
  EXPORT_SYMBOL_GPL(cpu_topology);
  
  static cpumask_t cpu_group_map(struct mask_info *info, unsigned int cpu)
  {
  	cpumask_t mask;
  
  	cpumask_copy(&mask, cpumask_of(cpu));
  	if (!topology_enabled || !MACHINE_HAS_TOPOLOGY)
  		return mask;
  	for (; info; info = info->next) {
  		if (cpumask_test_cpu(cpu, &info->mask))
  			return info->mask;
  	}
  	return mask;
  }
  
  static struct mask_info *add_cpus_to_mask(struct topology_cpu *tl_cpu,
  					  struct mask_info *book,
  					  struct mask_info *socket,
  					  int one_socket_per_cpu)
  {
  	unsigned int cpu;
  
  	for_each_set_bit(cpu, &tl_cpu->mask[0], TOPOLOGY_CPU_BITS) {
  		unsigned int rcpu;
  		int lcpu;
  
  		rcpu = TOPOLOGY_CPU_BITS - 1 - cpu + tl_cpu->origin;
  		lcpu = smp_find_processor_id(rcpu);
  		if (lcpu < 0)
  			continue;
  		cpumask_set_cpu(lcpu, &book->mask);
  		cpu_topology[lcpu].book_id = book->id;
  		cpumask_set_cpu(lcpu, &socket->mask);
  		cpu_topology[lcpu].core_id = rcpu;
  		if (one_socket_per_cpu) {
  			cpu_topology[lcpu].socket_id = rcpu;
  			socket = socket->next;
  		} else {
  			cpu_topology[lcpu].socket_id = socket->id;
  		}
  		smp_cpu_set_polarization(lcpu, tl_cpu->pp);
  	}
  	return socket;
  }
  
  static void clear_masks(void)
  {
  	struct mask_info *info;
  
  	info = &socket_info;
  	while (info) {
  		cpumask_clear(&info->mask);
  		info = info->next;
  	}
  	info = &book_info;
  	while (info) {
  		cpumask_clear(&info->mask);
  		info = info->next;
  	}
  }
  
  static union topology_entry *next_tle(union topology_entry *tle)
  {
  	if (!tle->nl)
  		return (union topology_entry *)((struct topology_cpu *)tle + 1);
  	return (union topology_entry *)((struct topology_container *)tle + 1);
  }
  
  static void __tl_to_masks_generic(struct sysinfo_15_1_x *info)
  {
  	struct mask_info *socket = &socket_info;
  	struct mask_info *book = &book_info;
  	union topology_entry *tle, *end;
  
  	tle = info->tle;
  	end = (union topology_entry *)((unsigned long)info + info->length);
  	while (tle < end) {
  		switch (tle->nl) {
  		case 2:
  			book = book->next;
  			book->id = tle->container.id;
  			break;
  		case 1:
  			socket = socket->next;
  			socket->id = tle->container.id;
  			break;
  		case 0:
  			add_cpus_to_mask(&tle->cpu, book, socket, 0);
  			break;
  		default:
  			clear_masks();
  			return;
  		}
  		tle = next_tle(tle);
  	}
  }
  
  static void __tl_to_masks_z10(struct sysinfo_15_1_x *info)
  {
  	struct mask_info *socket = &socket_info;
  	struct mask_info *book = &book_info;
  	union topology_entry *tle, *end;
  
  	tle = info->tle;
  	end = (union topology_entry *)((unsigned long)info + info->length);
  	while (tle < end) {
  		switch (tle->nl) {
  		case 1:
  			book = book->next;
  			book->id = tle->container.id;
  			break;
  		case 0:
  			socket = add_cpus_to_mask(&tle->cpu, book, socket, 1);
  			break;
  		default:
  			clear_masks();
  			return;
  		}
  		tle = next_tle(tle);
  	}
  }
  
  static void tl_to_masks(struct sysinfo_15_1_x *info)
  {
  	struct cpuid cpu_id;
  
  	spin_lock_irq(&topology_lock);
  	get_cpu_id(&cpu_id);
  	clear_masks();
  	switch (cpu_id.machine) {
  	case 0x2097:
  	case 0x2098:
  		__tl_to_masks_z10(info);
  		break;
  	default:
  		__tl_to_masks_generic(info);
  	}
  	spin_unlock_irq(&topology_lock);
  }
  
  static void topology_update_polarization_simple(void)
  {
  	int cpu;
  
  	mutex_lock(&smp_cpu_state_mutex);
  	for_each_possible_cpu(cpu)
  		smp_cpu_set_polarization(cpu, POLARIZATION_HRZ);
  	mutex_unlock(&smp_cpu_state_mutex);
  }
  
  static int ptf(unsigned long fc)
  {
  	int rc;
  
  	asm volatile(
  		"	.insn	rre,0xb9a20000,%1,%1\n"
  		"	ipm	%0\n"
  		"	srl	%0,28\n"
  		: "=d" (rc)
  		: "d" (fc)  : "cc");
  	return rc;
  }
  
  int topology_set_cpu_management(int fc)
  {
  	int cpu, rc;
  
  	if (!MACHINE_HAS_TOPOLOGY)
  		return -EOPNOTSUPP;
  	if (fc)
  		rc = ptf(PTF_VERTICAL);
  	else
  		rc = ptf(PTF_HORIZONTAL);
  	if (rc)
  		return -EBUSY;
  	for_each_possible_cpu(cpu)
  		smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
  	return rc;
  }
  
  static void update_cpu_masks(void)
  {
  	unsigned long flags;
  	int cpu;
  
  	spin_lock_irqsave(&topology_lock, flags);
  	for_each_possible_cpu(cpu) {
  		cpu_topology[cpu].core_mask = cpu_group_map(&socket_info, cpu);
  		cpu_topology[cpu].book_mask = cpu_group_map(&book_info, cpu);
  		if (!MACHINE_HAS_TOPOLOGY) {
  			cpu_topology[cpu].core_id = cpu;
  			cpu_topology[cpu].socket_id = cpu;
  			cpu_topology[cpu].book_id = cpu;
  		}
  	}
  	spin_unlock_irqrestore(&topology_lock, flags);
  }
  
  void store_topology(struct sysinfo_15_1_x *info)
  {
  	if (topology_max_mnest >= 3)
  		stsi(info, 15, 1, 3);
  	else
  		stsi(info, 15, 1, 2);
  }
  
  int arch_update_cpu_topology(void)
  {
  	struct sysinfo_15_1_x *info = tl_info;
  	struct device *dev;
  	int cpu;
  
  	if (!MACHINE_HAS_TOPOLOGY) {
  		update_cpu_masks();
  		topology_update_polarization_simple();
  		return 0;
  	}
  	store_topology(info);
  	tl_to_masks(info);
  	update_cpu_masks();
  	for_each_online_cpu(cpu) {
  		dev = get_cpu_device(cpu);
  		kobject_uevent(&dev->kobj, KOBJ_CHANGE);
  	}
  	return 1;
  }
  
  static void topology_work_fn(struct work_struct *work)
  {
  	rebuild_sched_domains();
  }
  
  void topology_schedule_update(void)
  {
  	schedule_work(&topology_work);
  }
  
  static void topology_timer_fn(unsigned long ignored)
  {
  	if (ptf(PTF_CHECK))
  		topology_schedule_update();
  	set_topology_timer();
  }
  
  static struct timer_list topology_timer =
  	TIMER_DEFERRED_INITIALIZER(topology_timer_fn, 0, 0);
  
  static atomic_t topology_poll = ATOMIC_INIT(0);
  
  static void set_topology_timer(void)
  {
  	if (atomic_add_unless(&topology_poll, -1, 0))
  		mod_timer(&topology_timer, jiffies + HZ / 10);
  	else
  		mod_timer(&topology_timer, jiffies + HZ * 60);
  }
  
  void topology_expect_change(void)
  {
  	if (!MACHINE_HAS_TOPOLOGY)
  		return;
  	/* This is racy, but it doesn't matter since it is just a heuristic.
  	 * Worst case is that we poll in a higher frequency for a bit longer.
  	 */
  	if (atomic_read(&topology_poll) > 60)
  		return;
  	atomic_add(60, &topology_poll);
  	set_topology_timer();
  }
  
  static int __init early_parse_topology(char *p)
  {
  	if (strncmp(p, "off", 3))
  		return 0;
  	topology_enabled = 0;
  	return 0;
  }
  early_param("topology", early_parse_topology);
  
  static void __init alloc_masks(struct sysinfo_15_1_x *info,
  			       struct mask_info *mask, int offset)
  {
  	int i, nr_masks;
  
  	nr_masks = info->mag[TOPOLOGY_NR_MAG - offset];
  	for (i = 0; i < info->mnest - offset; i++)
  		nr_masks *= info->mag[TOPOLOGY_NR_MAG - offset - 1 - i];
  	nr_masks = max(nr_masks, 1);
  	for (i = 0; i < nr_masks; i++) {
  		mask->next = alloc_bootmem_align(
  			roundup_pow_of_two(sizeof(struct mask_info)),
  			roundup_pow_of_two(sizeof(struct mask_info)));
  		mask = mask->next;
  	}
  }
  
  void __init s390_init_cpu_topology(void)
  {
  	struct sysinfo_15_1_x *info;
  	int i;
  
  	if (!MACHINE_HAS_TOPOLOGY)
  		return;
  	tl_info = alloc_bootmem_pages(PAGE_SIZE);
  	info = tl_info;
  	store_topology(info);
  	pr_info("The CPU configuration topology of the machine is:");
  	for (i = 0; i < TOPOLOGY_NR_MAG; i++)
  		printk(KERN_CONT " %d", info->mag[i]);
  	printk(KERN_CONT " / %d\n", info->mnest);
  	alloc_masks(info, &socket_info, 1);
  	alloc_masks(info, &book_info, 2);
  }
  
  static int cpu_management;
  
  static ssize_t dispatching_show(struct device *dev,
  				struct device_attribute *attr,
  				char *buf)
  {
  	ssize_t count;
  
  	mutex_lock(&smp_cpu_state_mutex);
  	count = sprintf(buf, "%d\n", cpu_management);
  	mutex_unlock(&smp_cpu_state_mutex);
  	return count;
  }
  
  static ssize_t dispatching_store(struct device *dev,
  				 struct device_attribute *attr,
  				 const char *buf,
  				 size_t count)
  {
  	int val, rc;
  	char delim;
  
  	if (sscanf(buf, "%d %c", &val, &delim) != 1)
  		return -EINVAL;
  	if (val != 0 && val != 1)
  		return -EINVAL;
  	rc = 0;
  	get_online_cpus();
  	mutex_lock(&smp_cpu_state_mutex);
  	if (cpu_management == val)
  		goto out;
  	rc = topology_set_cpu_management(val);
  	if (rc)
  		goto out;
  	cpu_management = val;
  	topology_expect_change();
  out:
  	mutex_unlock(&smp_cpu_state_mutex);
  	put_online_cpus();
  	return rc ? rc : count;
  }
  static DEVICE_ATTR(dispatching, 0644, dispatching_show,
  			 dispatching_store);
  
  static ssize_t cpu_polarization_show(struct device *dev,
  				     struct device_attribute *attr, char *buf)
  {
  	int cpu = dev->id;
  	ssize_t count;
  
  	mutex_lock(&smp_cpu_state_mutex);
  	switch (smp_cpu_get_polarization(cpu)) {
  	case POLARIZATION_HRZ:
  		count = sprintf(buf, "horizontal\n");
  		break;
  	case POLARIZATION_VL:
  		count = sprintf(buf, "vertical:low\n");
  		break;
  	case POLARIZATION_VM:
  		count = sprintf(buf, "vertical:medium\n");
  		break;
  	case POLARIZATION_VH:
  		count = sprintf(buf, "vertical:high\n");
  		break;
  	default:
  		count = sprintf(buf, "unknown\n");
  		break;
  	}
  	mutex_unlock(&smp_cpu_state_mutex);
  	return count;
  }
  static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);
  
  static struct attribute *topology_cpu_attrs[] = {
  	&dev_attr_polarization.attr,
  	NULL,
  };
  
  static struct attribute_group topology_cpu_attr_group = {
  	.attrs = topology_cpu_attrs,
  };
  
  int topology_cpu_init(struct cpu *cpu)
  {
  	return sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
  }
  
  const struct cpumask *cpu_coregroup_mask(int cpu)
  {
  	return &cpu_topology[cpu].core_mask;
  }
  
  static const struct cpumask *cpu_book_mask(int cpu)
  {
  	return &cpu_topology[cpu].book_mask;
  }
  
  static struct sched_domain_topology_level s390_topology[] = {
  	{ cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
  	{ cpu_book_mask, SD_INIT_NAME(BOOK) },
  	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
  	{ NULL, },
  };
  
  static int __init topology_init(void)
  {
  	if (!MACHINE_HAS_TOPOLOGY) {
  		topology_update_polarization_simple();
  		goto out;
  	}
  	set_topology_timer();
  out:
  
  	set_sched_topology(s390_topology);
  
  	return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
  }
  device_initcall(topology_init);
  