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topology.c

/*
 *    Copyright IBM Corp. 2007
 *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/bootmem.h>
#include <linux/sched.h>
#include <linux/workqueue.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <asm/delay.h>
#include <asm/s390_ext.h>
#include <asm/sysinfo.h>

#define CPU_BITS 64
#define NR_MAG 6

#define PTF_HORIZONTAL  (0UL)
#define PTF_VERTICAL    (1UL)
#define PTF_CHECK (2UL)

struct tl_cpu {
      unsigned char reserved0[4];
      unsigned char :6;
      unsigned char pp:2;
      unsigned char reserved1;
      unsigned short origin;
      unsigned long mask[CPU_BITS / BITS_PER_LONG];
};

struct tl_container {
      unsigned char reserved[8];
};

union tl_entry {
      unsigned char nl;
      struct tl_cpu cpu;
      struct tl_container container;
};

struct tl_info {
      unsigned char reserved0[2];
      unsigned short length;
      unsigned char mag[NR_MAG];
      unsigned char reserved1;
      unsigned char mnest;
      unsigned char reserved2[4];
      union tl_entry tle[0];
};

struct core_info {
      struct core_info *next;
      cpumask_t mask;
};

static void topology_work_fn(struct work_struct *work);
static struct tl_info *tl_info;
static struct core_info core_info;
static int machine_has_topology;
static int machine_has_topology_irq;
static struct timer_list topology_timer;
static void set_topology_timer(void);
static DECLARE_WORK(topology_work, topology_work_fn);

cpumask_t cpu_core_map[NR_CPUS];

cpumask_t cpu_coregroup_map(unsigned int cpu)
{
      struct core_info *core = &core_info;
      cpumask_t mask;

      cpus_clear(mask);
      if (!machine_has_topology)
            return cpu_present_map;
      mutex_lock(&smp_cpu_state_mutex);
      while (core) {
            if (cpu_isset(cpu, core->mask)) {
                  mask = core->mask;
                  break;
            }
            core = core->next;
      }
      mutex_unlock(&smp_cpu_state_mutex);
      if (cpus_empty(mask))
            mask = cpumask_of_cpu(cpu);
      return mask;
}

static void add_cpus_to_core(struct tl_cpu *tl_cpu, struct core_info *core)
{
      unsigned int cpu;

      for (cpu = find_first_bit(&tl_cpu->mask[0], CPU_BITS);
           cpu < CPU_BITS;
           cpu = find_next_bit(&tl_cpu->mask[0], CPU_BITS, cpu + 1))
      {
            unsigned int rcpu, lcpu;

            rcpu = CPU_BITS - 1 - cpu + tl_cpu->origin;
            for_each_present_cpu(lcpu) {
                  if (__cpu_logical_map[lcpu] == rcpu) {
                        cpu_set(lcpu, core->mask);
                        smp_cpu_polarization[lcpu] = tl_cpu->pp;
                  }
            }
      }
}

static void clear_cores(void)
{
      struct core_info *core = &core_info;

      while (core) {
            cpus_clear(core->mask);
            core = core->next;
      }
}

static union tl_entry *next_tle(union tl_entry *tle)
{
      if (tle->nl)
            return (union tl_entry *)((struct tl_container *)tle + 1);
      else
            return (union tl_entry *)((struct tl_cpu *)tle + 1);
}

static void tl_to_cores(struct tl_info *info)
{
      union tl_entry *tle, *end;
      struct core_info *core = &core_info;

      mutex_lock(&smp_cpu_state_mutex);
      clear_cores();
      tle = info->tle;
      end = (union tl_entry *)((unsigned long)info + info->length);
      while (tle < end) {
            switch (tle->nl) {
            case 5:
            case 4:
            case 3:
            case 2:
                  break;
            case 1:
                  core = core->next;
                  break;
            case 0:
                  add_cpus_to_core(&tle->cpu, core);
                  break;
            default:
                  clear_cores();
                  machine_has_topology = 0;
                  return;
            }
            tle = next_tle(tle);
      }
      mutex_unlock(&smp_cpu_state_mutex);
}

static void topology_update_polarization_simple(void)
{
      int cpu;

      mutex_lock(&smp_cpu_state_mutex);
      for_each_present_cpu(cpu)
            smp_cpu_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;
      int rc;

      if (!machine_has_topology)
            return -EOPNOTSUPP;
      if (fc)
            rc = ptf(PTF_VERTICAL);
      else
            rc = ptf(PTF_HORIZONTAL);
      if (rc)
            return -EBUSY;
      for_each_present_cpu(cpu)
            smp_cpu_polarization[cpu] = POLARIZATION_UNKNWN;
      return rc;
}

static void update_cpu_core_map(void)
{
      int cpu;

      for_each_present_cpu(cpu)
            cpu_core_map[cpu] = cpu_coregroup_map(cpu);
}

void arch_update_cpu_topology(void)
{
      struct tl_info *info = tl_info;
      struct sys_device *sysdev;
      int cpu;

      if (!machine_has_topology) {
            update_cpu_core_map();
            topology_update_polarization_simple();
            return;
      }
      stsi(info, 15, 1, 2);
      tl_to_cores(info);
      update_cpu_core_map();
      for_each_online_cpu(cpu) {
            sysdev = get_cpu_sysdev(cpu);
            kobject_uevent(&sysdev->kobj, KOBJ_CHANGE);
      }
}

static void topology_work_fn(struct work_struct *work)
{
      arch_reinit_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 void set_topology_timer(void)
{
      topology_timer.function = topology_timer_fn;
      topology_timer.data = 0;
      topology_timer.expires = jiffies + 60 * HZ;
      add_timer(&topology_timer);
}

static void topology_interrupt(__u16 code)
{
      schedule_work(&topology_work);
}

static int __init init_topology_update(void)
{
      int rc;

      rc = 0;
      if (!machine_has_topology) {
            topology_update_polarization_simple();
            goto out;
      }
      init_timer_deferrable(&topology_timer);
      if (machine_has_topology_irq) {
            rc = register_external_interrupt(0x2005, topology_interrupt);
            if (rc)
                  goto out;
            ctl_set_bit(0, 8);
      }
      else
            set_topology_timer();
out:
      update_cpu_core_map();
      return rc;
}
__initcall(init_topology_update);

void __init s390_init_cpu_topology(void)
{
      unsigned long long facility_bits;
      struct tl_info *info;
      struct core_info *core;
      int nr_cores;
      int i;

      if (stfle(&facility_bits, 1) <= 0)
            return;
      if (!(facility_bits & (1ULL << 52)) || !(facility_bits & (1ULL << 61)))
            return;
      machine_has_topology = 1;

      if (facility_bits & (1ULL << 51))
            machine_has_topology_irq = 1;

      tl_info = alloc_bootmem_pages(PAGE_SIZE);
      info = tl_info;
      stsi(info, 15, 1, 2);

      nr_cores = info->mag[NR_MAG - 2];
      for (i = 0; i < info->mnest - 2; i++)
            nr_cores *= info->mag[NR_MAG - 3 - i];

      printk(KERN_INFO "CPU topology:");
      for (i = 0; i < NR_MAG; i++)
            printk(" %d", info->mag[i]);
      printk(" / %d\n", info->mnest);

      core = &core_info;
      for (i = 0; i < nr_cores; i++) {
            core->next = alloc_bootmem(sizeof(struct core_info));
            core = core->next;
            if (!core)
                  goto error;
      }
      return;
error:
      machine_has_topology = 0;
      machine_has_topology_irq = 0;
}

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