path: root/arch/s390/kernel/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;