path: root/arch/s390/kernel/smp.c

/*
 *  arch/s390/kernel/smp.c
 *
 *    Copyright IBM Corp. 1999, 2009
 *    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.
 */

#define KMSG_COMPONENT "cpu"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#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/irqflags.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/cputime.h>
#include <asm/vdso.h>
#include <asm/cpu.h>
#include "entry.h"

/* logical cpu to cpu address */
int __cpu_logical_map[NR_CPUS];

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);

static int cpu_stopped(int cpu)
{
	__u32 status;

	switch (signal_processor_ps(&status, 0, cpu, sigp_sense)) {
	case sigp_status_stored:
		/* Check for stopped and check stop state */
		if (status & 0x50)
			return 1;
		break;
	default:
		break;
	}
	return 0;
}

void smp_send_stop(void)
{
	int cpu, rc;

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

	/* 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 (!cpu_stopped(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))
		generic_smp_call_function_interrupt();

	if (test_bit(ec_call_function_single, &bits))
		generic_smp_call_function_single_interrupt();
}

/*
 * 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);
}

void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
	int cpu;

	for_each_cpu(cpu, mask)
		smp_ext_bitcall(cpu, ec_call_function);
}

void arch_send_call_function_single_ipi(int cpu)
{
	smp_ext_bitcall(cpu, ec_call_function_single);
}

#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