[linux.git] / arch / parisc / kernel / smp.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
** SMP Support
**
** Copyright (C) 1999 Walt Drummond <[email protected]>
** Copyright (C) 1999 David Mosberger-Tang <[email protected]>
** Copyright (C) 2001,2004 Grant Grundler <[email protected]>
** 
** Lots of stuff stolen from arch/alpha/kernel/smp.c
** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^)
**
** Thanks to John Curry and Ullas Ponnadi. I learned a lot from their work.
** -grant (1/12/2001)
**
*/
#include <linux/types.h>
#include <linux/spinlock.h>

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched/mm.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/smp.h>
#include <linux/kernel_stat.h>
#include <linux/mm.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/ftrace.h>
#include <linux/cpu.h>

#include <linux/atomic.h>
#include <asm/current.h>
#include <asm/delay.h>
#include <asm/tlbflush.h>

#include <asm/io.h>
#include <asm/irq.h>		/* for CPU_IRQ_REGION and friends */
#include <asm/mmu_context.h>
#include <asm/page.h>
#include <asm/processor.h>
#include <asm/ptrace.h>
#include <asm/unistd.h>
#include <asm/cacheflush.h>

#undef DEBUG_SMP
#ifdef DEBUG_SMP
static int smp_debug_lvl = 0;
#define smp_debug(lvl, printargs...)		\
		if (lvl >= smp_debug_lvl)	\
			printk(printargs);
#else
#define smp_debug(lvl, ...)	do { } while(0)
#endif /* DEBUG_SMP */

volatile struct task_struct *smp_init_current_idle_task;

/* track which CPU is booting */
static volatile int cpu_now_booting;

static int parisc_max_cpus = 1;

static DEFINE_PER_CPU(spinlock_t, ipi_lock);

enum ipi_message_type {
	IPI_NOP=0,
	IPI_RESCHEDULE=1,
	IPI_CALL_FUNC,
	IPI_CPU_START,
	IPI_CPU_STOP,
	IPI_CPU_TEST
};


/********** SMP inter processor interrupt and communication routines */

#undef PER_CPU_IRQ_REGION
#ifdef PER_CPU_IRQ_REGION
/* XXX REVISIT Ignore for now.
**    *May* need this "hook" to register IPI handler
**    once we have perCPU ExtIntr switch tables.
*/
static void
ipi_init(int cpuid)
{
#error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region

	if(cpu_online(cpuid) )
	{
		switch_to_idle_task(current);
	}

	return;
}
#endif


/*
** Yoink this CPU from the runnable list... 
**
*/
static void
halt_processor(void) 
{
	/* REVISIT : redirect I/O Interrupts to another CPU? */
	/* REVISIT : does PM *know* this CPU isn't available? */
	set_cpu_online(smp_processor_id(), false);
	local_irq_disable();
	__pdc_cpu_rendezvous();
	for (;;)
		;
}


irqreturn_t __irq_entry
ipi_interrupt(int irq, void *dev_id) 
{
	int this_cpu = smp_processor_id();
	struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
	unsigned long ops;
	unsigned long flags;

	for (;;) {
		spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
		spin_lock_irqsave(lock, flags);
		ops = p->pending_ipi;
		p->pending_ipi = 0;
		spin_unlock_irqrestore(lock, flags);

		mb(); /* Order bit clearing and data access. */

		if (!ops)
		    break;

		while (ops) {
			unsigned long which = ffz(~ops);

			ops &= ~(1 << which);

			switch (which) {
			case IPI_NOP:
				smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
				break;
				
			case IPI_RESCHEDULE:
				smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
				inc_irq_stat(irq_resched_count);
				scheduler_ipi();
				break;

			case IPI_CALL_FUNC:
				smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
				inc_irq_stat(irq_call_count);
				generic_smp_call_function_interrupt();
				break;

			case IPI_CPU_START:
				smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
				break;

			case IPI_CPU_STOP:
				smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
				halt_processor();
				break;

			case IPI_CPU_TEST:
				smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
				break;

			default:
				printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
					this_cpu, which);
				return IRQ_NONE;
			} /* Switch */

			/* before doing more, let in any pending interrupts */
			if (ops) {
				local_irq_enable();
				local_irq_disable();
			}
		} /* while (ops) */
	}
	return IRQ_HANDLED;
}


static inline void
ipi_send(int cpu, enum ipi_message_type op)
{
	struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
	spinlock_t *lock = &per_cpu(ipi_lock, cpu);
	unsigned long flags;

	spin_lock_irqsave(lock, flags);
	p->pending_ipi |= 1 << op;
	gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
	spin_unlock_irqrestore(lock, flags);
}

static void
send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
{
	int cpu;

	for_each_cpu(cpu, mask)
		ipi_send(cpu, op);
}

static inline void
send_IPI_single(int dest_cpu, enum ipi_message_type op)
{
	BUG_ON(dest_cpu == NO_PROC_ID);

	ipi_send(dest_cpu, op);
}

static inline void
send_IPI_allbutself(enum ipi_message_type op)
{
	int i;

	preempt_disable();
	for_each_online_cpu(i) {
		if (i != smp_processor_id())
			send_IPI_single(i, op);
	}
	preempt_enable();
}


inline void 
smp_send_stop(void)	{ send_IPI_allbutself(IPI_CPU_STOP); }

void 
smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }

void
smp_send_all_nop(void)
{
	send_IPI_allbutself(IPI_NOP);
}

void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
	send_IPI_mask(mask, IPI_CALL_FUNC);
}

void arch_send_call_function_single_ipi(int cpu)
{
	send_IPI_single(cpu, IPI_CALL_FUNC);
}

/*
 * Called by secondaries to update state and initialize CPU registers.
 */
static void __init
smp_cpu_init(int cpunum)
{
	extern void init_IRQ(void);    /* arch/parisc/kernel/irq.c */
	extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */

	/* Set modes and Enable floating point coprocessor */
	init_per_cpu(cpunum);

	disable_sr_hashing();

	mb();

	/* Well, support 2.4 linux scheme as well. */
	if (cpu_online(cpunum))	{
		extern void machine_halt(void); /* arch/parisc.../process.c */

		printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
		machine_halt();
	}

	notify_cpu_starting(cpunum);

	set_cpu_online(cpunum, true);

	/* Initialise the idle task for this CPU */
	mmgrab(&init_mm);
	current->active_mm = &init_mm;
	BUG_ON(current->mm);
	enter_lazy_tlb(&init_mm, current);

	init_IRQ();   /* make sure no IRQs are enabled or pending */
	start_cpu_itimer();
}


/*
 * Slaves start using C here. Indirectly called from smp_slave_stext.
 * Do what start_kernel() and main() do for boot strap processor (aka monarch)
 */
void __init smp_callin(unsigned long pdce_proc)
{
	int slave_id = cpu_now_booting;

#ifdef CONFIG_64BIT
	WARN_ON(((unsigned long)(PAGE0->mem_pdc_hi) << 32
			| PAGE0->mem_pdc) != pdce_proc);
#endif

	smp_cpu_init(slave_id);

	flush_cache_all_local(); /* start with known state */
	flush_tlb_all_local(NULL);

	local_irq_enable();  /* Interrupts have been off until now */

	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);

	/* NOTREACHED */
	panic("smp_callin() AAAAaaaaahhhh....\n");
}

/*
 * Bring one cpu online.
 */
int smp_boot_one_cpu(int cpuid, struct task_struct *idle)
{
	const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
	long timeout;

	idle->cpu = cpuid;

	/* Let _start know what logical CPU we're booting
	** (offset into init_tasks[],cpu_data[])
	*/
	cpu_now_booting = cpuid;

	/* 
	** boot strap code needs to know the task address since
	** it also contains the process stack.
	*/
	smp_init_current_idle_task = idle ;
	mb();

	printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);

	/*
	** This gets PDC to release the CPU from a very tight loop.
	**
	** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
	** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which 
	** is executed after receiving the rendezvous signal (an interrupt to 
	** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the 
	** contents of memory are valid."
	*/
	gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
	mb();

	/* 
	 * OK, wait a bit for that CPU to finish staggering about. 
	 * Slave will set a bit when it reaches smp_cpu_init().
	 * Once the "monarch CPU" sees the bit change, it can move on.
	 */
	for (timeout = 0; timeout < 10000; timeout++) {
		if(cpu_online(cpuid)) {
			/* Which implies Slave has started up */
			cpu_now_booting = 0;
			smp_init_current_idle_task = NULL;
			goto alive ;
		}
		udelay(100);
		barrier();
	}
	printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
	return -1;

alive:
	/* Remember the Slave data */
	smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
		cpuid, timeout * 100);
	return 0;
}

void __init smp_prepare_boot_cpu(void)
{
	int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;

	/* Setup BSP mappings */
	printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);

	set_cpu_online(bootstrap_processor, true);
	set_cpu_present(bootstrap_processor, true);
}


/*
** inventory.c:do_inventory() hasn't yet been run and thus we
** don't 'discover' the additional CPUs until later.
*/
void __init smp_prepare_cpus(unsigned int max_cpus)
{
	int cpu;

	for_each_possible_cpu(cpu)
		spin_lock_init(&per_cpu(ipi_lock, cpu));

	init_cpu_present(cpumask_of(0));

	parisc_max_cpus = max_cpus;
	if (!max_cpus)
		printk(KERN_INFO "SMP mode deactivated.\n");
}


void smp_cpus_done(unsigned int cpu_max)
{
	return;
}


int __cpu_up(unsigned int cpu, struct task_struct *tidle)
{
	if (cpu != 0 && cpu < parisc_max_cpus && smp_boot_one_cpu(cpu, tidle))
		return -ENOSYS;

	return cpu_online(cpu) ? 0 : -ENOSYS;
}

#ifdef CONFIG_PROC_FS
int setup_profiling_timer(unsigned int multiplier)
{
	return -EINVAL;
}
#endif
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
	3	** SMP Support
	4	**
	5	** Copyright (C) 1999 Walt Drummond <[email protected]>
	6	** Copyright (C) 1999 David Mosberger-Tang <[email protected]>
	7	** Copyright (C) 2001,2004 Grant Grundler <[email protected]>
	8	**
	9	** Lots of stuff stolen from arch/alpha/kernel/smp.c
	10	** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^)
	11	**
7022672e	12	** Thanks to John Curry and Ullas Ponnadi. I learned a lot from their work.
1da177e4 LT	13	** -grant (1/12/2001)
1da177e4 LT	14	**
1da177e4	15	*/
1da177e4 LT	16	#include <linux/types.h>
1da177e4 LT	17	#include <linux/spinlock.h>
1da177e4 LT	18
	19	#include <linux/kernel.h>
	20	#include <linux/module.h>
68e21be2	21	#include <linux/sched/mm.h>
1da177e4 LT	22	#include <linux/init.h>
	23	#include <linux/interrupt.h>
	24	#include <linux/smp.h>
	25	#include <linux/kernel_stat.h>
	26	#include <linux/mm.h>
4e950f6f	27	#include <linux/err.h>
1da177e4 LT	28	#include <linux/delay.h>
1da177e4 LT	29	#include <linux/bitops.h>
d75f054a	30	#include <linux/ftrace.h>
ec2e0f98	31	#include <linux/cpu.h>
1da177e4	32
60063497	33	#include <linux/atomic.h>
1da177e4 LT	34	#include <asm/current.h>
1da177e4 LT	35	#include <asm/delay.h>
1b2425e3	36	#include <asm/tlbflush.h>
1da177e4 LT	37
	38	#include <asm/io.h>
	39	#include <asm/irq.h> /* for CPU_IRQ_REGION and friends */
	40	#include <asm/mmu_context.h>
	41	#include <asm/page.h>
1da177e4 LT	42	#include <asm/processor.h>
	43	#include <asm/ptrace.h>
	44	#include <asm/unistd.h>
	45	#include <asm/cacheflush.h>
	46
5492a0f0 KM	47	#undef DEBUG_SMP
	48	#ifdef DEBUG_SMP
	49	static int smp_debug_lvl = 0;
	50	#define smp_debug(lvl, printargs...) \
	51	if (lvl >= smp_debug_lvl) \
	52	printk(printargs);
	53	#else
ef017beb	54	#define smp_debug(lvl, ...) do { } while(0)
5492a0f0	55	#endif /* DEBUG_SMP */
1da177e4	56
1da177e4 LT	57	volatile struct task_struct *smp_init_current_idle_task;
1da177e4 LT	58
ef017beb	59	/* track which CPU is booting */
60ffef06	60	static volatile int cpu_now_booting;
1da177e4	61
60ffef06	62	static int parisc_max_cpus = 1;
1da177e4	63
6ad6c424	64	static DEFINE_PER_CPU(spinlock_t, ipi_lock);
1da177e4	65
1da177e4 LT	66	enum ipi_message_type {
	67	IPI_NOP=0,
	68	IPI_RESCHEDULE=1,
	69	IPI_CALL_FUNC,
	70	IPI_CPU_START,
	71	IPI_CPU_STOP,
	72	IPI_CPU_TEST
	73	};
	74
	75
	76	/********** SMP inter processor interrupt and communication routines */
	77
	78	#undef PER_CPU_IRQ_REGION
	79	#ifdef PER_CPU_IRQ_REGION
	80	/* XXX REVISIT Ignore for now.
	81	** May need this "hook" to register IPI handler
	82	** once we have perCPU ExtIntr switch tables.
	83	*/
	84	static void
	85	ipi_init(int cpuid)
	86	{
1da177e4 LT	87	#error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
	88
	89	if(cpu_online(cpuid) )
	90	{
	91	switch_to_idle_task(current);
	92	}
	93
	94	return;
	95	}
	96	#endif
	97
	98
	99	/*
	100	** Yoink this CPU from the runnable list...
	101	**
	102	*/
	103	static void
	104	halt_processor(void)
	105	{
1da177e4 LT	106	/* REVISIT : redirect I/O Interrupts to another CPU? */
1da177e4 LT	107	/* REVISIT : does PM know this CPU isn't available? */
9bc181d8	108	set_cpu_online(smp_processor_id(), false);
1da177e4	109	local_irq_disable();
507efd63	110	__pdc_cpu_rendezvous();
1da177e4 LT	111	for (;;)
1da177e4 LT	112	;
1da177e4 LT	113	}
	114
	115
d75f054a	116	irqreturn_t __irq_entry
c7753f18	117	ipi_interrupt(int irq, void *dev_id)
1da177e4 LT	118	{
1da177e4 LT	119	int this_cpu = smp_processor_id();
ef017beb	120	struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
1da177e4 LT	121	unsigned long ops;
	122	unsigned long flags;
	123
1da177e4	124	for (;;) {
3c97b5e9 KM	125	spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
3c97b5e9 KM	126	spin_lock_irqsave(lock, flags);
1da177e4 LT	127	ops = p->pending_ipi;
1da177e4 LT	128	p->pending_ipi = 0;
3c97b5e9	129	spin_unlock_irqrestore(lock, flags);
1da177e4 LT	130
	131	mb(); /* Order bit clearing and data access. */
	132
	133	if (!ops)
	134	break;
	135
	136	while (ops) {
	137	unsigned long which = ffz(~ops);
	138
d911aed8 JB	139	ops &= ~(1 << which);
d911aed8 JB	140
1da177e4	141	switch (which) {
d911aed8	142	case IPI_NOP:
5492a0f0	143	smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
d911aed8 JB	144	break;
d911aed8 JB	145
1da177e4	146	case IPI_RESCHEDULE:
5492a0f0	147	smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
cd85d551	148	inc_irq_stat(irq_resched_count);
184748cc	149	scheduler_ipi();
1da177e4 LT	150	break;
	151
	152	case IPI_CALL_FUNC:
5492a0f0	153	smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
b102f29b	154	inc_irq_stat(irq_call_count);
dbcf4787 JA	155	generic_smp_call_function_interrupt();
	156	break;
	157
1da177e4	158	case IPI_CPU_START:
5492a0f0	159	smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
1da177e4 LT	160	break;
	161
	162	case IPI_CPU_STOP:
5492a0f0	163	smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
1da177e4	164	halt_processor();
1da177e4 LT	165	break;
	166
	167	case IPI_CPU_TEST:
5492a0f0	168	smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
1da177e4 LT	169	break;
	170
	171	default:
	172	printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
	173	this_cpu, which);
1da177e4 LT	174	return IRQ_NONE;
1da177e4 LT	175	} /* Switch */
f4d0d40c HD	176
	177	/* before doing more, let in any pending interrupts */
	178	if (ops) {
	179	local_irq_enable();
	180	local_irq_disable();
	181	}
1da177e4 LT	182	} /* while (ops) */
	183	}
	184	return IRQ_HANDLED;
	185	}
	186
	187
	188	static inline void
	189	ipi_send(int cpu, enum ipi_message_type op)
	190	{
ef017beb	191	struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
3c97b5e9	192	spinlock_t *lock = &per_cpu(ipi_lock, cpu);
1da177e4 LT	193	unsigned long flags;
1da177e4 LT	194
3c97b5e9	195	spin_lock_irqsave(lock, flags);
1da177e4	196	p->pending_ipi \|= 1 << op;
ef017beb	197	gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
3c97b5e9	198	spin_unlock_irqrestore(lock, flags);
1da177e4 LT	199	}
1da177e4 LT	200
dbcf4787	201	static void
91887a36	202	send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
dbcf4787 JA	203	{
	204	int cpu;
	205
91887a36	206	for_each_cpu(cpu, mask)
dbcf4787 JA	207	ipi_send(cpu, op);
dbcf4787 JA	208	}
1da177e4 LT	209
	210	static inline void
	211	send_IPI_single(int dest_cpu, enum ipi_message_type op)
	212	{
7f2347a4	213	BUG_ON(dest_cpu == NO_PROC_ID);
1da177e4 LT	214
	215	ipi_send(dest_cpu, op);
	216	}
	217
	218	static inline void
	219	send_IPI_allbutself(enum ipi_message_type op)
	220	{
	221	int i;
1c2fb946 SS	222
1c2fb946 SS	223	preempt_disable();
394e3902 AM	224	for_each_online_cpu(i) {
394e3902 AM	225	if (i != smp_processor_id())
1da177e4 LT	226	send_IPI_single(i, op);
1da177e4 LT	227	}
1c2fb946	228	preempt_enable();
1da177e4 LT	229	}
	230
	231
	232	inline void
	233	smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); }
	234
1da177e4 LT	235	void
	236	smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
	237
d911aed8 JB	238	void
	239	smp_send_all_nop(void)
	240	{
	241	send_IPI_allbutself(IPI_NOP);
	242	}
	243
91887a36	244	void arch_send_call_function_ipi_mask(const struct cpumask *mask)
1da177e4	245	{
dbcf4787	246	send_IPI_mask(mask, IPI_CALL_FUNC);
1da177e4 LT	247	}
1da177e4 LT	248
dbcf4787 JA	249	void arch_send_call_function_single_ipi(int cpu)
dbcf4787 JA	250	{
528d8eb2	251	send_IPI_single(cpu, IPI_CALL_FUNC);
dbcf4787	252	}
1da177e4	253
1da177e4 LT	254	/*
	255	* Called by secondaries to update state and initialize CPU registers.
	256	*/
	257	static void __init
	258	smp_cpu_init(int cpunum)
	259	{
1da177e4	260	extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */
56f335c8	261	extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
1da177e4 LT	262
1da177e4 LT	263	/* Set modes and Enable floating point coprocessor */
a7e6601f	264	init_per_cpu(cpunum);
1da177e4 LT	265
	266	disable_sr_hashing();
	267
	268	mb();
	269
	270	/* Well, support 2.4 linux scheme as well. */
7ec6118c	271	if (cpu_online(cpunum)) {
1da177e4 LT	272	extern void machine_halt(void); /* arch/parisc.../process.c */
	273
	274	printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
	275	machine_halt();
ec2e0f98 SB	276	}
	277
	278	notify_cpu_starting(cpunum);
	279
9bc181d8	280	set_cpu_online(cpunum, true);
1da177e4 LT	281
1da177e4 LT	282	/* Initialise the idle task for this CPU */
f1f10076	283	mmgrab(&init_mm);
1da177e4	284	current->active_mm = &init_mm;
7f2347a4	285	BUG_ON(current->mm);
1da177e4 LT	286	enter_lazy_tlb(&init_mm, current);
1da177e4 LT	287
7022672e	288	init_IRQ(); /* make sure no IRQs are enabled or pending */
56f335c8	289	start_cpu_itimer();
1da177e4 LT	290	}
	291
	292
	293	/*
	294	* Slaves start using C here. Indirectly called from smp_slave_stext.
	295	* Do what start_kernel() and main() do for boot strap processor (aka monarch)
	296	*/
0ed1fe4a	297	void __init smp_callin(unsigned long pdce_proc)
1da177e4 LT	298	{
1da177e4 LT	299	int slave_id = cpu_now_booting;
1da177e4	300
0ed1fe4a HD	301	#ifdef CONFIG_64BIT
	302	WARN_ON(((unsigned long)(PAGE0->mem_pdc_hi) << 32
	303	\| PAGE0->mem_pdc) != pdce_proc);
	304	#endif
	305
1da177e4 LT	306	smp_cpu_init(slave_id);
1da177e4 LT	307
1da177e4	308	flush_cache_all_local(); /* start with known state */
1b2425e3	309	flush_tlb_all_local(NULL);
1da177e4 LT	310
	311	local_irq_enable(); /* Interrupts have been off until now */
	312
fc6d73d6	313	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
1da177e4 LT	314
	315	/* NOTREACHED */
	316	panic("smp_callin() AAAAaaaaahhhh....\n");
	317	}
	318
	319	/*
	320	* Bring one cpu online.
	321	*/
60ffef06	322	int smp_boot_one_cpu(int cpuid, struct task_struct *idle)
1da177e4	323	{
ef017beb	324	const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
1da177e4 LT	325	long timeout;
1da177e4 LT	326
2214c0e7	327	idle->cpu = cpuid;
1da177e4 LT	328
	329	/* Let _start know what logical CPU we're booting
	330	** (offset into init_tasks[],cpu_data[])
	331	*/
	332	cpu_now_booting = cpuid;
	333
	334	/*
	335	** boot strap code needs to know the task address since
	336	** it also contains the process stack.
	337	*/
	338	smp_init_current_idle_task = idle ;
	339	mb();
	340
ef017beb	341	printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);
1da177e4 LT	342
	343	/*
	344	** This gets PDC to release the CPU from a very tight loop.
	345	**
	346	** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
	347	** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
	348	** is executed after receiving the rendezvous signal (an interrupt to
	349	** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
	350	** contents of memory are valid."
	351	*/
ef017beb	352	gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
1da177e4 LT	353	mb();
	354
	355	/*
	356	* OK, wait a bit for that CPU to finish staggering about.
	357	* Slave will set a bit when it reaches smp_cpu_init().
	358	* Once the "monarch CPU" sees the bit change, it can move on.
	359	*/
	360	for (timeout = 0; timeout < 10000; timeout++) {
	361	if(cpu_online(cpuid)) {
	362	/* Which implies Slave has started up */
	363	cpu_now_booting = 0;
	364	smp_init_current_idle_task = NULL;
	365	goto alive ;
	366	}
	367	udelay(100);
	368	barrier();
	369	}
1da177e4 LT	370	printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
	371	return -1;
	372
	373	alive:
	374	/* Remember the Slave data */
5492a0f0	375	smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
1da177e4	376	cpuid, timeout * 100);
1da177e4 LT	377	return 0;
	378	}
	379
ef017beb	380	void __init smp_prepare_boot_cpu(void)
1da177e4	381	{
ef017beb	382	int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
1da177e4	383
1da177e4	384	/* Setup BSP mappings */
ef017beb	385	printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
1da177e4	386
9bc181d8 RR	387	set_cpu_online(bootstrap_processor, true);
9bc181d8 RR	388	set_cpu_present(bootstrap_processor, true);
1da177e4 LT	389	}
	390
	391
	392
	393	/*
	394	** inventory.c:do_inventory() hasn't yet been run and thus we
7022672e	395	** don't 'discover' the additional CPUs until later.
1da177e4 LT	396	*/
	397	void __init smp_prepare_cpus(unsigned int max_cpus)
	398	{
6ad6c424 TG	399	int cpu;
	400
	401	for_each_possible_cpu(cpu)
	402	spin_lock_init(&per_cpu(ipi_lock, cpu));
	403
9bc181d8	404	init_cpu_present(cpumask_of(0));
1da177e4 LT	405
	406	parisc_max_cpus = max_cpus;
	407	if (!max_cpus)
	408	printk(KERN_INFO "SMP mode deactivated.\n");
	409	}
	410
	411
	412	void smp_cpus_done(unsigned int cpu_max)
	413	{
	414	return;
	415	}
	416
	417
60ffef06	418	int __cpu_up(unsigned int cpu, struct task_struct *tidle)
1da177e4	419	{
5baf919d HD	420	if (cpu != 0 && cpu < parisc_max_cpus && smp_boot_one_cpu(cpu, tidle))
5baf919d HD	421	return -ENOSYS;
1da177e4 LT	422
	423	return cpu_online(cpu) ? 0 : -ENOSYS;
	424	}
	425
1da177e4	426	#ifdef CONFIG_PROC_FS
01f56832	427	int setup_profiling_timer(unsigned int multiplier)
1da177e4 LT	428	{
	429	return -EINVAL;
	430	}
	431	#endif