linux/linux-5.18.11/arch/sparc/kernel/smp_32.c

// SPDX-License-Identifier: GPL-2.0
/* smp.c: Sparc SMP support.
 *
 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
 * Copyright (C) 1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
 * Copyright (C) 2004 Keith M Wesolowski (wesolows@foobazco.org)
 */

#include <asm/head.h>

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/threads.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/cache.h>
#include <linux/delay.h>
#include <linux/profile.h>
#include <linux/cpu.h>

#include <asm/ptrace.h>
#include <linux/atomic.h>

#include <asm/irq.h>
#include <asm/page.h>
#include <asm/oplib.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/cpudata.h>
#include <asm/timer.h>
#include <asm/leon.h>

#include "kernel.h"
#include "irq.h"

volatile unsigned long cpu_callin_map[NR_CPUS] = {0,};

cpumask_t smp_commenced_mask = CPU_MASK_NONE;

const struct sparc32_ipi_ops *sparc32_ipi_ops;

/* The only guaranteed locking primitive available on all Sparc
 * processors is 'ldstub [%reg + immediate], %dest_reg' which atomically
 * places the current byte at the effective address into dest_reg and
 * places 0xff there afterwards.  Pretty lame locking primitive
 * compared to the Alpha and the Intel no?  Most Sparcs have 'swap'
 * instruction which is much better...
 */

void smp_store_cpu_info(int id)
{
	int cpu_node;
	int mid;

	cpu_data(id).udelay_val = loops_per_jiffy;

	cpu_find_by_mid(id, &cpu_node);
	cpu_data(id).clock_tick = prom_getintdefault(cpu_node,
						     "clock-frequency", 0);
	cpu_data(id).prom_node = cpu_node;
	mid = cpu_get_hwmid(cpu_node);

	if (mid < 0) {
		printk(KERN_NOTICE "No MID found for CPU%d at node 0x%08x", id, cpu_node);
		mid = 0;
	}
	cpu_data(id).mid = mid;
}

void __init smp_cpus_done(unsigned int max_cpus)
{
	unsigned long bogosum = 0;
	int cpu, num = 0;

	for_each_online_cpu(cpu) {
		num++;
		bogosum += cpu_data(cpu).udelay_val;
	}

	printk("Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
		num, bogosum/(500000/HZ),
		(bogosum/(5000/HZ))%100);

	switch(sparc_cpu_model) {
	case sun4m:
		smp4m_smp_done();
		break;
	case sun4d:
		smp4d_smp_done();
		break;
	case sparc_leon:
		leon_smp_done();
		break;
	case sun4e:
		printk("SUN4E\n");
		BUG();
		break;
	case sun4u:
		printk("SUN4U\n");
		BUG();
		break;
	default:
		printk("UNKNOWN!\n");
		BUG();
		break;
	}
}

void cpu_panic(void)
{
	printk("CPU[%d]: Returns from cpu_idle!\n", smp_processor_id());
	panic("SMP bolixed\n");
}

struct linux_prom_registers smp_penguin_ctable = { 0 };

void smp_send_reschedule(int cpu)
{
	/*
	 * CPU model dependent way of implementing IPI generation targeting
	 * a single CPU. The trap handler needs only to do trap entry/return
	 * to call schedule.
	 */
	sparc32_ipi_ops->resched(cpu);
}

void smp_send_stop(void)
{
}

void arch_send_call_function_single_ipi(int cpu)
{
	/* trigger one IPI single call on one CPU */
	sparc32_ipi_ops->single(cpu);
}

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

	/* trigger IPI mask call on each CPU */
	for_each_cpu(cpu, mask)
		sparc32_ipi_ops->mask_one(cpu);
}

void smp_resched_interrupt(void)
{
	irq_enter();
	scheduler_ipi();
	local_cpu_data().irq_resched_count++;
	irq_exit();
	/* re-schedule routine called by interrupt return code. */
}

void smp_call_function_single_interrupt(void)
{
	irq_enter();
	generic_smp_call_function_single_interrupt();
	local_cpu_data().irq_call_count++;
	irq_exit();
}

void smp_call_function_interrupt(void)
{
	irq_enter();
	generic_smp_call_function_interrupt();
	local_cpu_data().irq_call_count++;
	irq_exit();
}

int setup_profiling_timer(unsigned int multiplier)
{
	return -EINVAL;
}

void __init smp_prepare_cpus(unsigned int max_cpus)
{
	int i, cpuid, extra;

	printk("Entering SMP Mode...\n");

	extra = 0;
	for (i = 0; !cpu_find_by_instance(i, NULL, &cpuid); i++) {
		if (cpuid >= NR_CPUS)
			extra++;
	}
	/* i = number of cpus */
	if (extra && max_cpus > i - extra)
		printk("Warning: NR_CPUS is too low to start all cpus\n");

	smp_store_cpu_info(boot_cpu_id);

	switch(sparc_cpu_model) {
	case sun4m:
		smp4m_boot_cpus();
		break;
	case sun4d:
		smp4d_boot_cpus();
		break;
	case sparc_leon:
		leon_boot_cpus();
		break;
	case sun4e:
		printk("SUN4E\n");
		BUG();
		break;
	case sun4u:
		printk("SUN4U\n");
		BUG();
		break;
	default:
		printk("UNKNOWN!\n");
		BUG();
		break;
	}
}

/* Set this up early so that things like the scheduler can init
 * properly.  We use the same cpu mask for both the present and
 * possible cpu map.
 */
void __init smp_setup_cpu_possible_map(void)
{
	int instance, mid;

	instance = 0;
	while (!cpu_find_by_instance(instance, NULL, &mid)) {
		if (mid < NR_CPUS) {
			set_cpu_possible(mid, true);
			set_cpu_present(mid, true);
		}
		instance++;
	}
}

void __init smp_prepare_boot_cpu(void)
{
	int cpuid = hard_smp_processor_id();

	if (cpuid >= NR_CPUS) {
		prom_printf("Serious problem, boot cpu id >= NR_CPUS\n");
		prom_halt();
	}
	if (cpuid != 0)
		printk("boot cpu id != 0, this could work but is untested\n");

	current_thread_info()->cpu = cpuid;
	set_cpu_online(cpuid, true);
	set_cpu_possible(cpuid, true);
}

int __cpu_up(unsigned int cpu, struct task_struct *tidle)
{
	int ret=0;

	switch(sparc_cpu_model) {
	case sun4m:
		ret = smp4m_boot_one_cpu(cpu, tidle);
		break;
	case sun4d:
		ret = smp4d_boot_one_cpu(cpu, tidle);
		break;
	case sparc_leon:
		ret = leon_boot_one_cpu(cpu, tidle);
		break;
	case sun4e:
		printk("SUN4E\n");
		BUG();
		break;
	case sun4u:
		printk("SUN4U\n");
		BUG();
		break;
	default:
		printk("UNKNOWN!\n");
		BUG();
		break;
	}

	if (!ret) {
		cpumask_set_cpu(cpu, &smp_commenced_mask);
		while (!cpu_online(cpu))
			mb();
	}
	return ret;
}

static void arch_cpu_pre_starting(void *arg)
{
	local_ops->cache_all();
	local_ops->tlb_all();

	switch(sparc_cpu_model) {
	case sun4m:
		sun4m_cpu_pre_starting(arg);
		break;
	case sun4d:
		sun4d_cpu_pre_starting(arg);
		break;
	case sparc_leon:
		leon_cpu_pre_starting(arg);
		break;
	default:
		BUG();
	}
}

static void arch_cpu_pre_online(void *arg)
{
	unsigned int cpuid = hard_smp_processor_id();

	register_percpu_ce(cpuid);

	calibrate_delay();
	smp_store_cpu_info(cpuid);

	local_ops->cache_all();
	local_ops->tlb_all();

	switch(sparc_cpu_model) {
	case sun4m:
		sun4m_cpu_pre_online(arg);
		break;
	case sun4d:
		sun4d_cpu_pre_online(arg);
		break;
	case sparc_leon:
		leon_cpu_pre_online(arg);
		break;
	default:
		BUG();
	}
}

static void sparc_start_secondary(void *arg)
{
	unsigned int cpu;

	/*
	 * SMP booting is extremely fragile in some architectures. So run
	 * the cpu initialization code first before anything else.
	 */
	arch_cpu_pre_starting(arg);

	cpu = smp_processor_id();

	notify_cpu_starting(cpu);
	arch_cpu_pre_online(arg);

	/* Set the CPU in the cpu_online_mask */
	set_cpu_online(cpu, true);

	/* Enable local interrupts now */
	local_irq_enable();

	wmb();
	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);

	/* We should never reach here! */
	BUG();
}

void smp_callin(void)
{
	sparc_start_secondary(NULL);
}

void smp_bogo(struct seq_file *m)
{
	int i;
	
	for_each_online_cpu(i) {
		seq_printf(m,
			   "Cpu%dBogo\t: %lu.%02lu\n",
			   i,
			   cpu_data(i).udelay_val/(500000/HZ),
			   (cpu_data(i).udelay_val/(5000/HZ))%100);
	}
}

void smp_info(struct seq_file *m)
{
	int i;

	seq_printf(m, "State:\n");
	for_each_online_cpu(i)
		seq_printf(m, "CPU%d\t\t: online\n", i);
}