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

// SPDX-License-Identifier: GPL-2.0
/*
 *  SMP related functions
 *
 *    Copyright IBM Corp. 1999, 2012
 *    Author(s): Denis Joseph Barrow,
 *		 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
 *
 * The code outside of smp.c uses logical cpu numbers, only smp.c does
 * the translation of logical to physical cpu ids. All new code that
 * operates on physical cpu numbers needs to go into smp.c.
 */

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

#include <linux/workqueue.h>
#include <linux/memblock.h>
#include <linux/export.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/interrupt.h>
#include <linux/irqflags.h>
#include <linux/cpu.h>
#include <linux/slab.h>
#include <linux/sched/hotplug.h>
#include <linux/sched/task_stack.h>
#include <linux/crash_dump.h>
#include <linux/kprobes.h>
#include <asm/asm-offsets.h>
#include <asm/diag.h>
#include <asm/switch_to.h>
#include <asm/facility.h>
#include <asm/ipl.h>
#include <asm/setup.h>
#include <asm/irq.h>
#include <asm/tlbflush.h>
#include <asm/vtimer.h>
#include <asm/lowcore.h>
#include <asm/sclp.h>
#include <asm/debug.h>
#include <asm/os_info.h>
#include <asm/sigp.h>
#include <asm/idle.h>
#include <asm/nmi.h>
#include <asm/stacktrace.h>
#include <asm/topology.h>
#include "entry.h"

enum {
	ec_schedule = 0,
	ec_call_function_single,
	ec_stop_cpu,
	ec_mcck_pending,
};

enum {
	CPU_STATE_STANDBY,
	CPU_STATE_CONFIGURED,
};

static DEFINE_PER_CPU(struct cpu *, cpu_device);

struct pcpu {
	struct lowcore *lowcore;	/* lowcore page(s) for the cpu */
	unsigned long ec_mask;		/* bit mask for ec_xxx functions */
	unsigned long ec_clk;		/* sigp timestamp for ec_xxx */
	signed char state;		/* physical cpu state */
	signed char polarization;	/* physical polarization */
	u16 address;			/* physical cpu address */
};

static u8 boot_core_type;
static struct pcpu pcpu_devices[NR_CPUS];

unsigned int smp_cpu_mt_shift;
EXPORT_SYMBOL(smp_cpu_mt_shift);

unsigned int smp_cpu_mtid;
EXPORT_SYMBOL(smp_cpu_mtid);

#ifdef CONFIG_CRASH_DUMP
__vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
#endif

static unsigned int smp_max_threads __initdata = -1U;

static int __init early_nosmt(char *s)
{
	smp_max_threads = 1;
	return 0;
}
early_param("nosmt", early_nosmt);

static int __init early_smt(char *s)
{
	get_option(&s, &smp_max_threads);
	return 0;
}
early_param("smt", early_smt);

/*
 * The smp_cpu_state_mutex must be held when changing the state or polarization
 * member of a pcpu data structure within the pcpu_devices arreay.
 */
DEFINE_MUTEX(smp_cpu_state_mutex);

/*
 * Signal processor helper functions.
 */
static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm)
{
	int cc;

	while (1) {
		cc = __pcpu_sigp(addr, order, parm, NULL);
		if (cc != SIGP_CC_BUSY)
			return cc;
		cpu_relax();
	}
}

static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 <