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/asm-offsets.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 */
unsigned short __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, int);

static int raw_cpu_stopped(int cpu)
{
	u32 status;

	switch (raw_sigp_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;
}

static inline int cpu_stopped(int cpu)
{
	return raw_cpu_stopped(cpu_logical_map(cpu));
}

void smp_switch_to_ipl_cpu(void (*func)(void *), void *data)
{
	struct _lowcore *lc, *current_lc;
	struct stack_frame *sf;
	struct pt_regs *regs;
	unsigned long sp;

	if (smp_processor_id() == 0)
		func(data);
	__load_psw_mask(PSW_BASE_BITS | PSW_DEFAULT_KEY);
	/* Disable lowcore protection */
	__ctl_clear_bit(0, 28);
	current_lc = lowcore_ptr[smp_processor_id()];
	lc = lowcore_ptr[0];
	if (!lc)
		lc = current_lc;
	lc->restart_psw.mask = PSW_BASE_BITS | PSW_DEFAULT_KEY;
	lc->restart_psw.addr = PSW_ADDR_AMODE | (unsigned long) smp_restart_cpu;
	if (!cpu_online(0))
		smp_switch_to_cpu(func, data, 0, stap(), __cpu_logical_map[0]);
	while (sigp(0, sigp_stop_and_store_status) == sigp_busy)
		cpu_relax();
	sp = lc->panic_stack;
	sp -= sizeof(struct pt_regs);
	regs = (struct pt_regs *) sp;
	memcpy(&regs->gprs, &current_lc->gpregs_save_area, sizeof(regs->gprs));
	regs->psw = lc->psw_save_area;
	sp -= STACK_FRAME_OVERHEAD;
	sf = (struct stack_frame *) sp;
	sf->back_chain = regs->gprs[15];
	smp_switch_to_cpu(func, data, sp, stap(), __cpu_logical_map[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) {