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smp.c

/*
 *  arch/s390/kernel/smp.c
 *
 *    Copyright IBM Corp. 1999,2007
 *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
 *           Martin Schwidefsky (schwidefsky@de.ibm.com)
 *           Heiko Carstens (heiko.carstens@de.ibm.com)
 *
 *  based on other smp stuff by
 *    (c) 1995 Alan Cox, CymruNET Ltd  <alan@cymru.net>
 *    (c) 1998 Ingo Molnar
 *
 * We work with logical cpu numbering everywhere we can. The only
 * functions using the real cpu address (got from STAP) are the sigp
 * functions. For all other functions we use the identity mapping.
 * That means that cpu_number_map[i] == i for every cpu. cpu_number_map is
 * used e.g. to find the idle task belonging to a logical cpu. Every array
 * in the kernel is sorted by the logical cpu number and not by the physical
 * one which is causing all the confusion with __cpu_logical_map and
 * cpu_number_map in other architectures.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/err.h>
#include <linux/spinlock.h>
#include <linux/kernel_stat.h>
#include <linux/delay.h>
#include <linux/cache.h>
#include <linux/interrupt.h>
#include <linux/cpu.h>
#include <linux/timex.h>
#include <linux/bootmem.h>
#include <asm/ipl.h>
#include <asm/setup.h>
#include <asm/sigp.h>
#include <asm/pgalloc.h>
#include <asm/irq.h>
#include <asm/s390_ext.h>
#include <asm/cpcmd.h>
#include <asm/tlbflush.h>
#include <asm/timer.h>
#include <asm/lowcore.h>
#include <asm/sclp.h>
#include <asm/cpu.h>
#include "entry.h"

/*
 * An array with a pointer the lowcore of every CPU.
 */
struct _lowcore *lowcore_ptr[NR_CPUS];
EXPORT_SYMBOL(lowcore_ptr);

cpumask_t cpu_online_map = CPU_MASK_NONE;
EXPORT_SYMBOL(cpu_online_map);

cpumask_t cpu_possible_map = CPU_MASK_ALL;
EXPORT_SYMBOL(cpu_possible_map);

static struct task_struct *current_set[NR_CPUS];

static u8 smp_cpu_type;
static int smp_use_sigp_detection;

enum s390_cpu_state {
      CPU_STATE_STANDBY,
      CPU_STATE_CONFIGURED,
};

DEFINE_MUTEX(smp_cpu_state_mutex);
int smp_cpu_polarization[NR_CPUS];
static int smp_cpu_state[NR_CPUS];
static int cpu_management;

static DEFINE_PER_CPU(struct cpu, cpu_devices);

static void smp_ext_bitcall(int, ec_bit_sig);

/*
 * Structure and data for __smp_call_function_map(). This is designed to
 * minimise static memory requirements. It also looks cleaner.
 */
static DEFINE_SPINLOCK(call_lock);

struct call_data_struct {
      void (*func) (void *info);
      void *info;
      cpumask_t started;
      cpumask_t finished;
      int wait;
};

static struct call_data_struct *call_data;

/*
 * 'Call function' interrupt callback
 */
static void do_call_function(void)
{
      void (*func) (void *info) = call_data->func;
      void *info = call_data->info;
      int wait = call_data->wait;

      cpu_set(smp_processor_id(), call_data->started);
      (*func)(info);
      if (wait)
            cpu_set(smp_processor_id(), call_data->finished);;
}

static void __smp_call_function_map(void (*func) (void *info), void *info,
                            int wait, cpumask_t map)
{
      struct call_data_struct data;
      int cpu, local = 0;

      /*
       * Can deadlock when interrupts are disabled or if in wrong context.
       */
      WARN_ON(irqs_disabled() || in_irq());

      /*
       * Check for local function call. We have to have the same call order
       * as in on_each_cpu() because of machine_restart_smp().
       */
      if (cpu_isset(smp_processor_id(), map)) {
            local = 1;
            cpu_clear(smp_processor_id(), map);
      }

      cpus_and(map, map, cpu_online_map);
      if (cpus_empty(map))
            goto out;

      data.func = func;
      data.info = info;
      data.started = CPU_MASK_NONE;
      data.wait = wait;
      if (wait)
            data.finished = CPU_MASK_NONE;

      call_data = &data;

      for_each_cpu_mask(cpu, map)
            smp_ext_bitcall(cpu, ec_call_function);

      /* Wait for response */
      while (!cpus_equal(map, data.started))
            cpu_relax();
      if (wait)
            while (!cpus_equal(map, data.finished))
                  cpu_relax();
out:
      if (local) {
            local_irq_disable();
            func(info);
            local_irq_enable();
      }
}

/*
 * smp_call_function:
 * @func: the function to run; this must be fast and non-blocking
 * @info: an arbitrary pointer to pass to the function
 * @wait: if true, wait (atomically) until function has completed on other CPUs
 *
 * Run a function on all other CPUs.
 *
 * You must not call this function with disabled interrupts, from a
 * hardware interrupt handler or from a bottom half.
 */
int smp_call_function(void (*func) (void *info), void *info, int wait)
{
      cpumask_t map;

      spin_lock(&call_lock);
      map = cpu_online_map;
      cpu_clear(smp_processor_id(), map);
      __smp_call_function_map(func, info, wait, map);
      spin_unlock(&call_lock);
      return 0;
}
EXPORT_SYMBOL(smp_call_function);

/*
 * smp_call_function_single:
 * @cpu: the CPU where func should run
 * @func: the function to run; this must be fast and non-blocking
 * @info: an arbitrary pointer to pass to the function
 * @wait: if true, wait (atomically) until function has completed on other CPUs
 *
 * Run a function on one processor.
 *
 * You must not call this function with disabled interrupts, from a
 * hardware interrupt handler or from a bottom half.
 */
int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
                       int wait)
{
      spin_lock(&call_lock);
      __smp_call_function_map(func, info, wait, cpumask_of_cpu(cpu));
      spin_unlock(&call_lock);
      return 0;
}
EXPORT_SYMBOL(smp_call_function_single);

/**
 * smp_call_function_mask(): Run a function on a set of other CPUs.
 * @mask: The set of cpus to run on.  Must not include the current cpu.
 * @func: The function to run. This must be fast and non-blocking.
 * @info: An arbitrary pointer to pass to the function.
 * @wait: If true, wait (atomically) until function has completed on other CPUs.
 *
 * Returns 0 on success, else a negative status code.
 *
 * If @wait is true, then returns once @func has returned; otherwise
 * it returns just before the target cpu calls @func.
 *
 * You must not call this function with disabled interrupts or from a
 * hardware interrupt handler or from a bottom half handler.
 */
int smp_call_function_mask(cpumask_t mask, void (*func)(void *), void *info,
                     int wait)
{
      spin_lock(&call_lock);
      cpu_clear(smp_processor_id(), mask);
      __smp_call_function_map(func, info, wait, mask);
      spin_unlock(&call_lock);
      return 0;
}
EXPORT_SYMBOL(smp_call_function_mask);

void smp_send_stop(void)
{
      int cpu, rc;

      /* Disable all interrupts/machine checks */
      __load_psw_mask(psw_kernel_bits & ~PSW_MASK_MCHECK);

      /* write magic number to zero page (absolute 0) */
      lowcore_ptr[smp_processor_id()]->panic_magic = __PANIC_MAGIC;

      /* stop all processors */
      for_each_online_cpu(cpu) {
            if (cpu == smp_processor_id())
                  continue;
            do {
                  rc = signal_processor(cpu, sigp_stop);
            } while (rc == sigp_busy);

            while (!smp_cpu_not_running(cpu))
                  cpu_relax();
      }
}

/*
 * This is the main routine where commands issued by other
 * cpus are handled.
 */

static void do_ext_call_interrupt(__u16 code)
{
      unsigned long bits;

      /*
       * handle bit signal external calls
       *
       * For the ec_schedule signal we have to do nothing. All the work
       * is done automatically when we return from the interrupt.
       */
      bits = xchg(&S390_lowcore.ext_call_fast, 0);

      if (test_bit(ec_call_function, &bits))
            do_call_function();
}

/*
 * Send an external call sigp to another cpu and return without waiting
 * for its completion.
 */
static void smp_ext_bitcall(int cpu, ec_bit_sig sig)
{
      /*
       * Set signaling bit in lowcore of target cpu and kick it
       */
      set_bit(sig, (unsigned long *) &lowcore_ptr[cpu]->ext_call_fast);
      while (signal_processor(cpu, sigp_emergency_signal) == sigp_busy)
            udelay(10);
}

#ifndef CONFIG_64BIT
/*
 * this function sends a 'purge tlb' signal to another CPU.
 */
static void smp_ptlb_callback(void *info)
{
      __tlb_flush_local();
}

void smp_ptlb_all(void)
{
      on_each_cpu(smp_ptlb_callback, NULL, 1);
}
EXPORT_SYMBOL(smp_ptlb_all);
#endif /* ! CONFIG_64BIT */

/*
 * this function sends a 'reschedule' IPI to another CPU.
 * it goes straight through and wastes no time serializing
 * anything. Worst case is that we lose a reschedule ...
 */
void smp_send_reschedule(int cpu)
{
      smp_ext_bitcall(cpu, ec_schedule);
}

/*
 * parameter area for the set/clear control bit callbacks
 */
struct ec_creg_mask_parms {
      unsigned long orvals[16];
      unsigned long andvals[16];
};

/*
 * callback for setting/clearing control bits
 */
static void smp_ctl_bit_callback(void *info)
{
      struct ec_creg_mask_parms *pp = info;
      unsigned long cregs[16];
      int i;

      __ctl_store(cregs, 0, 15);
      for (i = 0; i <= 15; i++)
            cregs[i] = (cregs[i] & pp->andvals[i]) | pp->orvals[i];
      __ctl_load(cregs, 0, 15);
}

/*
 * Set a bit in a control register of all cpus
 */
void smp_ctl_set_bit(int cr, int bit)
{
      struct ec_creg_mask_parms parms;

      memset(&parms.orvals, 0, sizeof(parms.orvals));
      memset(&parms.andvals, 0xff, sizeof(parms.andvals));
      parms.orvals[cr] = 1 << bit;
      on_each_cpu(smp_ctl_bit_callback, &parms, 1);
}
EXPORT_SYMBOL(smp_ctl_set_bit);

/*
 * Clear a bit in a control register of all cpus
 */
void smp_ctl_clear_bit(int cr, int bit)
{
      struct ec_creg_mask_parms parms;

      memset(&parms.orvals, 0, sizeof(parms.orvals));
      memset(&parms.andvals, 0xff, sizeof(parms.andvals));
      parms.andvals[cr] = ~(1L << bit);
      on_each_cpu(smp_ctl_bit_callback, &parms, 1);
}
EXPORT_SYMBOL(smp_ctl_clear_bit);

/*
 * In early ipl state a temp. logically cpu number is needed, so the sigp
 * functions can be used to sense other cpus. Since NR_CPUS is >= 2 on
 * CONFIG_SMP and the ipl cpu is logical cpu 0, it must be 1.
 */
#define CPU_INIT_NO     1

#if defined(CONFIG_ZFCPDUMP) || defined(CONFIG_ZFCPDUMP_MODULE)

/*
 * zfcpdump_prefix_array holds prefix registers for the following scenario:
 * 64 bit zfcpdump kernel and 31 bit kernel which is to be dumped. We have to
 * save its prefix registers, since they get lost, when switching from 31 bit
 * to 64 bit.
 */
unsigned int zfcpdump_prefix_array[NR_CPUS + 1] \
      __attribute__((__section__(".data")));

static void __init smp_get_save_area(unsigned int cpu, unsigned int phy_cpu)
{
      if (ipl_info.type != IPL_TYPE_FCP_DUMP)
            return;
      if (cpu >= NR_CPUS) {
            printk(KERN_WARNING "Registers for cpu %i not saved since dump "
                   "kernel was compiled with NR_CPUS=%i\n", cpu, NR_CPUS);
            return;
      }
      zfcpdump_save_areas[cpu] = kmalloc(sizeof(union save_area), GFP_KERNEL);
      __cpu_logical_map[CPU_INIT_NO] = (__u16) phy_cpu;
      while (signal_processor(CPU_INIT_NO, sigp_stop_and_store_status) ==
             sigp_busy)
            cpu_relax();
      memcpy(zfcpdump_save_areas[cpu],
             (void *)(unsigned long) store_prefix() + SAVE_AREA_BASE,
             SAVE_AREA_SIZE);
#ifdef CONFIG_64BIT
      /* copy original prefix register */
      zfcpdump_save_areas[cpu]->s390x.pref_reg = zfcpdump_prefix_array[cpu];
#endif
}

union save_area *zfcpdump_save_areas[NR_CPUS + 1];
EXPORT_SYMBOL_GPL(zfcpdump_save_areas);

#else

static inline void smp_get_save_area(unsigned int cpu, unsigned int phy_cpu) { }

#endif /* CONFIG_ZFCPDUMP || CONFIG_ZFCPDUMP_MODULE */

static int cpu_stopped(int cpu)
{
      __u32 status;

      /* Check for stopped state */
      if (signal_processor_ps(&status, 0, cpu, sigp_sense) ==
          sigp_status_stored) {
            if (status & 0x40)
                  return 1;
      }
      return 0;
}

static int cpu_known(int cpu_id)
{
      int cpu;

      for_each_present_cpu(cpu) {
            if (__cpu_logical_map[cpu] == cpu_id)
                  return 1;
      }
      return 0;
}

static int smp_rescan_cpus_sigp(cpumask_t avail)
{
      int cpu_id, logical_cpu;

      logical_cpu = first_cpu(avail);
      if (logical_cpu == NR_CPUS)
            return 0;
      for (cpu_id = 0; cpu_id <= 65535; cpu_id++) {
            if (cpu_known(cpu_id))
                  continue;
            __cpu_logical_map[logical_cpu] = cpu_id;
            smp_cpu_polarization[logical_cpu] = POLARIZATION_UNKNWN;
            if (!cpu_stopped(logical_cpu))
                  continue;
            cpu_set(logical_cpu, cpu_present_map);
            smp_cpu_state[logical_cpu] = CPU_STATE_CONFIGURED;
            logical_cpu = next_cpu(logical_cpu, avail);
            if (logical_cpu == NR_CPUS)
                  break;
      }
      return 0;
}

static int smp_rescan_cpus_sclp(cpumask_t avail)
{
      struct sclp_cpu_info *info;
      int cpu_id, logical_cpu, cpu;
      int rc;

      logical_cpu = first_cpu(avail);
      if (logical_cpu == NR_CPUS)
            return 0;
      info = kmalloc(sizeof(*info), GFP_KERNEL);
      if (!info)
            return -ENOMEM;
      rc = sclp_get_cpu_info(info);
      if (rc)
            goto out;
      for (cpu = 0; cpu < info->combined; cpu++) {
            if (info->has_cpu_type && info->cpu[cpu].type != smp_cpu_type)
                  continue;
            cpu_id = info->cpu[cpu].address;
            if (cpu_known(cpu_id))
                  continue;
            __cpu_logical_map[logical_cpu] = cpu_id;
            smp_cpu_polarization[logical_cpu] = POLARIZATION_UNKNWN;
            cpu_set(logical_cpu, cpu_present_map);
            if (cpu >= info->configured)
                  smp_cpu_state[logical_cpu] = CPU_STATE_STANDBY;
            else
                  smp_cpu_state[logical_cpu] = CPU_STATE_CONFIGURED;
            logical_cpu = next_cpu(logical_cpu, avail);
            if (logical_cpu == NR_CPUS)
                  break;
      }
out:
      kfree(info);
      return rc;
}

static int __smp_rescan_cpus(void)
{
      cpumask_t avail;

      cpus_xor(avail, cpu_possible_map, cpu_present_map);
      if (smp_use_sigp_detection)
            return smp_rescan_cpus_sigp(avail);
      else
            return smp_rescan_cpus_sclp(avail);
}

static void __init smp_detect_cpus(void)
{
      unsigned int cpu, c_cpus, s_cpus;
      struct sclp_cpu_info *info;
      u16 boot_cpu_addr, cpu_addr;

      c_cpus = 1;
      s_cpus = 0;
      boot_cpu_addr = S390_lowcore.cpu_data.cpu_addr;
      info = kmalloc(sizeof(*info), GFP_KERNEL);
      if (!info)
            panic("smp_detect_cpus failed to allocate memory\n");
      /* Use sigp detection algorithm if sclp doesn't work. */
      if (sclp_get_cpu_info(info)) {
            smp_use_sigp_detection = 1;
            for (cpu = 0; cpu <= 65535; cpu++) {
                  if (cpu == boot_cpu_addr)
                        continue;
                  __cpu_logical_map[CPU_INIT_NO] = cpu;
                  if (!cpu_stopped(CPU_INIT_NO))
                        continue;
                  smp_get_save_area(c_cpus, cpu);
                  c_cpus++;
            }
            goto out;
      }

      if (info->has_cpu_type) {
            for (cpu = 0; cpu < info->combined; cpu++) {
                  if (info->cpu[cpu].address == boot_cpu_addr) {
                        smp_cpu_type = info->cpu[cpu].type;
                        break;
                  }
            }
      }

      for (cpu = 0; cpu < info->combined; cpu++) {
            if (info->has_cpu_type && info->cpu[cpu].type != smp_cpu_type)
                  continue;
            cpu_addr = info->cpu[cpu].address;
            if (cpu_addr == boot_cpu_addr)
                  continue;
            __cpu_logical_map[CPU_INIT_NO] = cpu_addr;
            if (!cpu_stopped(CPU_INIT_NO)) {
                  s_cpus++;
                  continue;
            }
            smp_get_save_area(c_cpus, cpu_addr);
            c_cpus++;
      }
out:
      kfree(info);
      printk(KERN_INFO "CPUs: %d configured, %d standby\n", c_cpus, s_cpus);
      get_online_cpus();
      __smp_rescan_cpus();
      put_online_cpus();
}

/*
 *    Activate a secondary processor.
 */
int __cpuinit start_secondary(void *cpuvoid)
{
      /* Setup the cpu */
      cpu_init();
      preempt_disable();
      /* Enable TOD clock interrupts on the secondary cpu. */
      init_cpu_timer();
#ifdef CONFIG_VIRT_TIMER
      /* Enable cpu timer interrupts on the secondary cpu. */
      init_cpu_vtimer();
#endif
      /* Enable pfault pseudo page faults on this cpu. */
      pfault_init();

      /* Mark this cpu as online */
      spin_lock(&call_lock);
      cpu_set(smp_processor_id(), cpu_online_map);
      spin_unlock(&call_lock);
      /* Switch on interrupts */
      local_irq_enable();
      /* Print info about this processor */
      print_cpu_info(&S390_lowcore.cpu_data);
      /* cpu_idle will call schedule for us */
      cpu_idle();
      return 0;
}

static void __init smp_create_idle(unsigned int cpu)
{
      struct task_struct *p;

      /*
       *  don't care about the psw and regs settings since we'll never
       *  reschedule the forked task.
       */
      p = fork_idle(cpu);
      if (IS_ERR(p))
            panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
      current_set[cpu] = p;
}

static int __cpuinit smp_alloc_lowcore(int cpu)
{
      unsigned long async_stack, panic_stack;
      struct _lowcore *lowcore;
      int lc_order;

      lc_order = sizeof(long) == 8 ? 1 : 0;
      lowcore = (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, lc_order);
      if (!lowcore)
            return -ENOMEM;
      async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
      panic_stack = __get_free_page(GFP_KERNEL);
      if (!panic_stack || !async_stack)
            goto out;
      memcpy(lowcore, &S390_lowcore, 512);
      memset((char *)lowcore + 512, 0, sizeof(*lowcore) - 512);
      lowcore->async_stack = async_stack + ASYNC_SIZE;
      lowcore->panic_stack = panic_stack + PAGE_SIZE;

#ifndef CONFIG_64BIT
      if (MACHINE_HAS_IEEE) {
            unsigned long save_area;

            save_area = get_zeroed_page(GFP_KERNEL);
            if (!save_area)
                  goto out_save_area;
            lowcore->extended_save_area_addr = (u32) save_area;
      }
#endif
      lowcore_ptr[cpu] = lowcore;
      return 0;

#ifndef CONFIG_64BIT
out_save_area:
      free_page(panic_stack);
#endif
out:
      free_pages(async_stack, ASYNC_ORDER);
      free_pages((unsigned long) lowcore, lc_order);
      return -ENOMEM;
}

#ifdef CONFIG_HOTPLUG_CPU
static void smp_free_lowcore(int cpu)
{
      struct _lowcore *lowcore;
      int lc_order;

      lc_order = sizeof(long) == 8 ? 1 : 0;
      lowcore = lowcore_ptr[cpu];
#ifndef CONFIG_64BIT
      if (MACHINE_HAS_IEEE)
            free_page((unsigned long) lowcore->extended_save_area_addr);
#endif
      free_page(lowcore->panic_stack - PAGE_SIZE);
      free_pages(lowcore->async_stack - ASYNC_SIZE, ASYNC_ORDER);
      free_pages((unsigned long) lowcore, lc_order);
      lowcore_ptr[cpu] = NULL;
}
#endif /* CONFIG_HOTPLUG_CPU */

/* Upping and downing of CPUs */
int __cpuinit __cpu_up(unsigned int cpu)
{
      struct task_struct *idle;
      struct _lowcore *cpu_lowcore;
      struct stack_frame *sf;
      sigp_ccode ccode;

      if (smp_cpu_state[cpu] != CPU_STATE_CONFIGURED)
            return -EIO;
      if (smp_alloc_lowcore(cpu))
            return -ENOMEM;

      ccode = signal_processor_p((__u32)(unsigned long)(lowcore_ptr[cpu]),
                           cpu, sigp_set_prefix);
      if (ccode) {
            printk("sigp_set_prefix failed for cpu %d "
                   "with condition code %d\n",
                   (int) cpu, (int) ccode);
            return -EIO;
      }

      idle = current_set[cpu];
      cpu_lowcore = lowcore_ptr[cpu];
      cpu_lowcore->kernel_stack = (unsigned long)
            task_stack_page(idle) + THREAD_SIZE;
      cpu_lowcore->thread_info = (unsigned long) task_thread_info(idle);
      sf = (struct stack_frame *) (cpu_lowcore->kernel_stack
                             - sizeof(struct pt_regs)
                             - sizeof(struct stack_frame));
      memset(sf, 0, sizeof(struct stack_frame));
      sf->gprs[9] = (unsigned long) sf;
      cpu_lowcore->save_area[15] = (unsigned long) sf;
      __ctl_store(cpu_lowcore->cregs_save_area, 0, 15);
      asm volatile(
            "     stam  0,15,0(%0)"
            : : "a" (&cpu_lowcore->access_regs_save_area) : "memory");
      cpu_lowcore->percpu_offset = __per_cpu_offset[cpu];
      cpu_lowcore->current_task = (unsigned long) idle;
      cpu_lowcore->cpu_data.cpu_nr = cpu;
      cpu_lowcore->kernel_asce = S390_lowcore.kernel_asce;
      cpu_lowcore->ipl_device = S390_lowcore.ipl_device;
      eieio();

      while (signal_processor(cpu, sigp_restart) == sigp_busy)
            udelay(10);

      while (!cpu_online(cpu))
            cpu_relax();
      return 0;
}

static int __init setup_possible_cpus(char *s)
{
      int pcpus, cpu;

      pcpus = simple_strtoul(s, NULL, 0);
      cpu_possible_map = cpumask_of_cpu(0);
      for (cpu = 1; cpu < pcpus && cpu < NR_CPUS; cpu++)
            cpu_set(cpu, cpu_possible_map);
      return 0;
}
early_param("possible_cpus", setup_possible_cpus);

#ifdef CONFIG_HOTPLUG_CPU

int __cpu_disable(void)
{
      struct ec_creg_mask_parms cr_parms;
      int cpu = smp_processor_id();

      cpu_clear(cpu, cpu_online_map);

      /* Disable pfault pseudo page faults on this cpu. */
      pfault_fini();

      memset(&cr_parms.orvals, 0, sizeof(cr_parms.orvals));
      memset(&cr_parms.andvals, 0xff, sizeof(cr_parms.andvals));

      /* disable all external interrupts */
      cr_parms.orvals[0] = 0;
      cr_parms.andvals[0] = ~(1 << 15 | 1 << 14 | 1 << 13 | 1 << 12 |
                        1 << 11 | 1 << 10 | 1 <<  6 | 1 <<  4);
      /* disable all I/O interrupts */
      cr_parms.orvals[6] = 0;
      cr_parms.andvals[6] = ~(1 << 31 | 1 << 30 | 1 << 29 | 1 << 28 |
                        1 << 27 | 1 << 26 | 1 << 25 | 1 << 24);
      /* disable most machine checks */
      cr_parms.orvals[14] = 0;
      cr_parms.andvals[14] = ~(1 << 28 | 1 << 27 | 1 << 26 |
                         1 << 25 | 1 << 24);

      smp_ctl_bit_callback(&cr_parms);

      return 0;
}

void __cpu_die(unsigned int cpu)
{
      /* Wait until target cpu is down */
      while (!smp_cpu_not_running(cpu))
            cpu_relax();
      smp_free_lowcore(cpu);
      printk(KERN_INFO "Processor %d spun down\n", cpu);
}

void cpu_die(void)
{
      idle_task_exit();
      signal_processor(smp_processor_id(), sigp_stop);
      BUG();
      for (;;);
}

#endif /* CONFIG_HOTPLUG_CPU */

void __init smp_prepare_cpus(unsigned int max_cpus)
{
#ifndef CONFIG_64BIT
      unsigned long save_area = 0;
#endif
      unsigned long async_stack, panic_stack;
      struct _lowcore *lowcore;
      unsigned int cpu;
      int lc_order;

      smp_detect_cpus();

      /* request the 0x1201 emergency signal external interrupt */
      if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
            panic("Couldn't request external interrupt 0x1201");
      print_cpu_info(&S390_lowcore.cpu_data);

      /* Reallocate current lowcore, but keep its contents. */
      lc_order = sizeof(long) == 8 ? 1 : 0;
      lowcore = (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, lc_order);
      panic_stack = __get_free_page(GFP_KERNEL);
      async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
#ifndef CONFIG_64BIT
      if (MACHINE_HAS_IEEE)
            save_area = get_zeroed_page(GFP_KERNEL);
#endif
      local_irq_disable();
      local_mcck_disable();
      lowcore_ptr[smp_processor_id()] = lowcore;
      *lowcore = S390_lowcore;
      lowcore->panic_stack = panic_stack + PAGE_SIZE;
      lowcore->async_stack = async_stack + ASYNC_SIZE;
#ifndef CONFIG_64BIT
      if (MACHINE_HAS_IEEE)
            lowcore->extended_save_area_addr = (u32) save_area;
#endif
      set_prefix((u32)(unsigned long) lowcore);
      local_mcck_enable();
      local_irq_enable();
      for_each_possible_cpu(cpu)
            if (cpu != smp_processor_id())
                  smp_create_idle(cpu);
}

void __init smp_prepare_boot_cpu(void)
{
      BUG_ON(smp_processor_id() != 0);

      current_thread_info()->cpu = 0;
      cpu_set(0, cpu_present_map);
      cpu_set(0, cpu_online_map);
      S390_lowcore.percpu_offset = __per_cpu_offset[0];
      current_set[0] = current;
      smp_cpu_state[0] = CPU_STATE_CONFIGURED;
      smp_cpu_polarization[0] = POLARIZATION_UNKNWN;
}

void __init smp_cpus_done(unsigned int max_cpus)
{
}

/*
 * the frequency of the profiling timer can be changed
 * by writing a multiplier value into /proc/profile.
 *
 * usually you want to run this on all CPUs ;)
 */
int setup_profiling_timer(unsigned int multiplier)
{
      return 0;
}

#ifdef CONFIG_HOTPLUG_CPU
static ssize_t cpu_configure_show(struct sys_device *dev,
                        struct sysdev_attribute *attr, char *buf)
{
      ssize_t count;

      mutex_lock(&smp_cpu_state_mutex);
      count = sprintf(buf, "%d\n", smp_cpu_state[dev->id]);
      mutex_unlock(&smp_cpu_state_mutex);
      return count;
}

static ssize_t cpu_configure_store(struct sys_device *dev,
                          struct sysdev_attribute *attr,
                          const char *buf, size_t count)
{
      int cpu = dev->id;
      int val, rc;
      char delim;

      if (sscanf(buf, "%d %c", &val, &delim) != 1)
            return -EINVAL;
      if (val != 0 && val != 1)
            return -EINVAL;

      get_online_cpus();
      mutex_lock(&smp_cpu_state_mutex);
      rc = -EBUSY;
      if (cpu_online(cpu))
            goto out;
      rc = 0;
      switch (val) {
      case 0:
            if (smp_cpu_state[cpu] == CPU_STATE_CONFIGURED) {
                  rc = sclp_cpu_deconfigure(__cpu_logical_map[cpu]);
                  if (!rc) {
                        smp_cpu_state[cpu] = CPU_STATE_STANDBY;
                        smp_cpu_polarization[cpu] = POLARIZATION_UNKNWN;
                  }
            }
            break;
      case 1:
            if (smp_cpu_state[cpu] == CPU_STATE_STANDBY) {
                  rc = sclp_cpu_configure(__cpu_logical_map[cpu]);
                  if (!rc) {
                        smp_cpu_state[cpu] = CPU_STATE_CONFIGURED;
                        smp_cpu_polarization[cpu] = POLARIZATION_UNKNWN;
                  }
            }
            break;
      default:
            break;
      }
out:
      mutex_unlock(&smp_cpu_state_mutex);
      put_online_cpus();
      return rc ? rc : count;
}
static SYSDEV_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
#endif /* CONFIG_HOTPLUG_CPU */

static ssize_t cpu_polarization_show(struct sys_device *dev,
                             struct sysdev_attribute *attr, char *buf)
{
      int cpu = dev->id;
      ssize_t count;

      mutex_lock(&smp_cpu_state_mutex);
      switch (smp_cpu_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 SYSDEV_ATTR(polarization, 0444, cpu_polarization_show, NULL);

static ssize_t show_cpu_address(struct sys_device *dev,
                        struct sysdev_attribute *attr, char *buf)
{
      return sprintf(buf, "%d\n", __cpu_logical_map[dev->id]);
}
static SYSDEV_ATTR(address, 0444, show_cpu_address, NULL);


static struct attribute *cpu_common_attrs[] = {
#ifdef CONFIG_HOTPLUG_CPU
      &attr_configure.attr,
#endif
      &attr_address.attr,
      &attr_polarization.attr,
      NULL,
};

static struct attribute_group cpu_common_attr_group = {
      .attrs = cpu_common_attrs,
};

static ssize_t show_capability(struct sys_device *dev,
                        struct sysdev_attribute *attr, char *buf)
{
      unsigned int capability;
      int rc;

      rc = get_cpu_capability(&capability);
      if (rc)
            return rc;
      return sprintf(buf, "%u\n", capability);
}
static SYSDEV_ATTR(capability, 0444, show_capability, NULL);

static ssize_t show_idle_count(struct sys_device *dev,
                        struct sysdev_attribute *attr, char *buf)
{
      struct s390_idle_data *idle;
      unsigned long long idle_count;

      idle = &per_cpu(s390_idle, dev->id);
      spin_lock_irq(&idle->lock);
      idle_count = idle->idle_count;
      spin_unlock_irq(&idle->lock);
      return sprintf(buf, "%llu\n", idle_count);
}
static SYSDEV_ATTR(idle_count, 0444, show_idle_count, NULL);

static ssize_t show_idle_time(struct sys_device *dev,
                        struct sysdev_attribute *attr, char *buf)
{
      struct s390_idle_data *idle;
      unsigned long long new_time;

      idle = &per_cpu(s390_idle, dev->id);
      spin_lock_irq(&idle->lock);
      if (idle->in_idle) {
            new_time = get_clock();
            idle->idle_time += new_time - idle->idle_enter;
            idle->idle_enter = new_time;
      }
      new_time = idle->idle_time;
      spin_unlock_irq(&idle->lock);
      return sprintf(buf, "%llu\n", new_time >> 12);
}
static SYSDEV_ATTR(idle_time_us, 0444, show_idle_time, NULL);

static struct attribute *cpu_online_attrs[] = {
      &attr_capability.attr,
      &attr_idle_count.attr,
      &attr_idle_time_us.attr,
      NULL,
};

static struct attribute_group cpu_online_attr_group = {
      .attrs = cpu_online_attrs,
};

static int __cpuinit smp_cpu_notify(struct notifier_block *self,
                            unsigned long action, void *hcpu)
{
      unsigned int cpu = (unsigned int)(long)hcpu;
      struct cpu *c = &per_cpu(cpu_devices, cpu);
      struct sys_device *s = &c->sysdev;
      struct s390_idle_data *idle;

      switch (action) {
      case CPU_ONLINE:
      case CPU_ONLINE_FROZEN:
            idle = &per_cpu(s390_idle, cpu);
            spin_lock_irq(&idle->lock);
            idle->idle_enter = 0;
            idle->idle_time = 0;
            idle->idle_count = 0;
            spin_unlock_irq(&idle->lock);
            if (sysfs_create_group(&s->kobj, &cpu_online_attr_group))
                  return NOTIFY_BAD;
            break;
      case CPU_DEAD:
      case CPU_DEAD_FROZEN:
            sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
            break;
      }
      return NOTIFY_OK;
}

static struct notifier_block __cpuinitdata smp_cpu_nb = {
      .notifier_call = smp_cpu_notify,
};

static int __devinit smp_add_present_cpu(int cpu)
{
      struct cpu *c = &per_cpu(cpu_devices, cpu);
      struct sys_device *s = &c->sysdev;
      int rc;

      c->hotpluggable = 1;
      rc = register_cpu(c, cpu);
      if (rc)
            goto out;
      rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
      if (rc)
            goto out_cpu;
      if (!cpu_online(cpu))
            goto out;
      rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
      if (!rc)
            return 0;
      sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
out_cpu:
#ifdef CONFIG_HOTPLUG_CPU
      unregister_cpu(c);
#endif
out:
      return rc;
}

#ifdef CONFIG_HOTPLUG_CPU

int __ref smp_rescan_cpus(void)
{
      cpumask_t newcpus;
      int cpu;
      int rc;

      get_online_cpus();
      mutex_lock(&smp_cpu_state_mutex);
      newcpus = cpu_present_map;
      rc = __smp_rescan_cpus();
      if (rc)
            goto out;
      cpus_andnot(newcpus, cpu_present_map, newcpus);
      for_each_cpu_mask(cpu, newcpus) {
            rc = smp_add_present_cpu(cpu);
            if (rc)
                  cpu_clear(cpu, cpu_present_map);
      }
      rc = 0;
out:
      mutex_unlock(&smp_cpu_state_mutex);
      put_online_cpus();
      if (!cpus_empty(newcpus))
            topology_schedule_update();
      return rc;
}

static ssize_t __ref rescan_store(struct sys_device *dev,
                          struct sysdev_attribute *attr,
                          const char *buf,
                          size_t count)
{
      int rc;

      rc = smp_rescan_cpus();
      return rc ? rc : count;
}
static SYSDEV_ATTR(rescan, 0200, NULL, rescan_store);
#endif /* CONFIG_HOTPLUG_CPU */

static ssize_t dispatching_show(struct sys_device *dev,
                        struct sysdev_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 sys_device *dev,
                         struct sysdev_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)
            cpu_management = val;
out:
      mutex_unlock(&smp_cpu_state_mutex);
      put_online_cpus();
      return rc ? rc : count;
}
static SYSDEV_ATTR(dispatching, 0644, dispatching_show, dispatching_store);

static int __init topology_init(void)
{
      int cpu;
      int rc;

      register_cpu_notifier(&smp_cpu_nb);

#ifdef CONFIG_HOTPLUG_CPU
      rc = sysfs_create_file(&cpu_sysdev_class.kset.kobj,
                         &attr_rescan.attr);
      if (rc)
            return rc;
#endif
      rc = sysfs_create_file(&cpu_sysdev_class.kset.kobj,
                         &attr_dispatching.attr);
      if (rc)
            return rc;
      for_each_present_cpu(cpu) {
            rc = smp_add_present_cpu(cpu);
            if (rc)
                  return rc;
      }
      return 0;
}
subsys_initcall(topology_init);

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