Linux Audio

Check our new training course

Loading...
v5.9
  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3** SMP Support
  4**
  5** Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
  6** Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
  7** Copyright (C) 2001,2004 Grant Grundler <grundler@parisc-linux.org>
  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**
 12** Thanks to John Curry and Ullas Ponnadi. I learned a lot from their work.
 13** -grant (1/12/2001)
 14**
 
 
 
 
 15*/
 16#include <linux/types.h>
 17#include <linux/spinlock.h>
 18
 19#include <linux/kernel.h>
 20#include <linux/module.h>
 21#include <linux/sched/mm.h>
 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>
 27#include <linux/err.h>
 28#include <linux/delay.h>
 29#include <linux/bitops.h>
 30#include <linux/ftrace.h>
 31#include <linux/cpu.h>
 32
 33#include <linux/atomic.h>
 34#include <asm/current.h>
 35#include <asm/delay.h>
 36#include <asm/tlbflush.h>
 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>
 
 
 42#include <asm/processor.h>
 43#include <asm/ptrace.h>
 44#include <asm/unistd.h>
 45#include <asm/cacheflush.h>
 46
 47#undef DEBUG_SMP
 48#ifdef DEBUG_SMP
 49static int smp_debug_lvl = 0;
 50#define smp_debug(lvl, printargs...)		\
 51		if (lvl >= smp_debug_lvl)	\
 52			printk(printargs);
 53#else
 54#define smp_debug(lvl, ...)	do { } while(0)
 55#endif /* DEBUG_SMP */
 56
 57volatile struct task_struct *smp_init_current_idle_task;
 58
 59/* track which CPU is booting */
 60static volatile int cpu_now_booting;
 61
 62static int parisc_max_cpus = 1;
 63
 64static DEFINE_PER_CPU(spinlock_t, ipi_lock);
 65
 66enum 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*/
 84static void
 85ipi_init(int cpuid)
 86{
 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*/
103static void
104halt_processor(void) 
105{
106	/* REVISIT : redirect I/O Interrupts to another CPU? */
107	/* REVISIT : does PM *know* this CPU isn't available? */
108	set_cpu_online(smp_processor_id(), false);
109	local_irq_disable();
110	__pdc_cpu_rendezvous();
111	for (;;)
112		;
113}
114
115
116irqreturn_t __irq_entry
117ipi_interrupt(int irq, void *dev_id) 
118{
119	int this_cpu = smp_processor_id();
120	struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
121	unsigned long ops;
122	unsigned long flags;
123
124	for (;;) {
125		spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
126		spin_lock_irqsave(lock, flags);
127		ops = p->pending_ipi;
128		p->pending_ipi = 0;
129		spin_unlock_irqrestore(lock, flags);
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
139			ops &= ~(1 << which);
140
141			switch (which) {
142			case IPI_NOP:
143				smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
144				break;
145				
146			case IPI_RESCHEDULE:
147				smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
148				inc_irq_stat(irq_resched_count);
149				scheduler_ipi();
150				break;
151
152			case IPI_CALL_FUNC:
153				smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
154				inc_irq_stat(irq_call_count);
155				generic_smp_call_function_interrupt();
156				break;
157
158			case IPI_CPU_START:
159				smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
160				break;
161
162			case IPI_CPU_STOP:
163				smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
164				halt_processor();
165				break;
166
167			case IPI_CPU_TEST:
168				smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
169				break;
170
171			default:
172				printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
173					this_cpu, which);
174				return IRQ_NONE;
175			} /* Switch */
176		/* let in any pending interrupts */
177		local_irq_enable();
178		local_irq_disable();
179		} /* while (ops) */
180	}
181	return IRQ_HANDLED;
182}
183
184
185static inline void
186ipi_send(int cpu, enum ipi_message_type op)
187{
188	struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
189	spinlock_t *lock = &per_cpu(ipi_lock, cpu);
190	unsigned long flags;
191
192	spin_lock_irqsave(lock, flags);
193	p->pending_ipi |= 1 << op;
194	gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
195	spin_unlock_irqrestore(lock, flags);
196}
197
198static void
199send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
200{
201	int cpu;
202
203	for_each_cpu(cpu, mask)
204		ipi_send(cpu, op);
205}
206
207static inline void
208send_IPI_single(int dest_cpu, enum ipi_message_type op)
209{
210	BUG_ON(dest_cpu == NO_PROC_ID);
211
212	ipi_send(dest_cpu, op);
213}
214
215static inline void
216send_IPI_allbutself(enum ipi_message_type op)
217{
218	int i;
219	
220	for_each_online_cpu(i) {
221		if (i != smp_processor_id())
222			send_IPI_single(i, op);
223	}
224}
225
226
227inline void 
228smp_send_stop(void)	{ send_IPI_allbutself(IPI_CPU_STOP); }
229
230void 
231smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
232
233void
234smp_send_all_nop(void)
235{
236	send_IPI_allbutself(IPI_NOP);
237}
238
239void arch_send_call_function_ipi_mask(const struct cpumask *mask)
240{
241	send_IPI_mask(mask, IPI_CALL_FUNC);
242}
243
244void arch_send_call_function_single_ipi(int cpu)
245{
246	send_IPI_single(cpu, IPI_CALL_FUNC);
247}
248
249/*
250 * Called by secondaries to update state and initialize CPU registers.
251 */
252static void __init
253smp_cpu_init(int cpunum)
254{
 
255	extern void init_IRQ(void);    /* arch/parisc/kernel/irq.c */
256	extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
257
258	/* Set modes and Enable floating point coprocessor */
259	init_per_cpu(cpunum);
260
261	disable_sr_hashing();
262
263	mb();
264
265	/* Well, support 2.4 linux scheme as well. */
266	if (cpu_online(cpunum))	{
267		extern void machine_halt(void); /* arch/parisc.../process.c */
268
269		printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
270		machine_halt();
271	}
272
273	notify_cpu_starting(cpunum);
274
275	set_cpu_online(cpunum, true);
276
277	/* Initialise the idle task for this CPU */
278	mmgrab(&init_mm);
279	current->active_mm = &init_mm;
280	BUG_ON(current->mm);
281	enter_lazy_tlb(&init_mm, current);
282
283	init_IRQ();   /* make sure no IRQs are enabled or pending */
284	start_cpu_itimer();
285}
286
287
288/*
289 * Slaves start using C here. Indirectly called from smp_slave_stext.
290 * Do what start_kernel() and main() do for boot strap processor (aka monarch)
291 */
292void __init smp_callin(unsigned long pdce_proc)
293{
294	int slave_id = cpu_now_booting;
295
296#ifdef CONFIG_64BIT
297	WARN_ON(((unsigned long)(PAGE0->mem_pdc_hi) << 32
298			| PAGE0->mem_pdc) != pdce_proc);
299#endif
300
301	smp_cpu_init(slave_id);
302	preempt_disable();
303
304	flush_cache_all_local(); /* start with known state */
305	flush_tlb_all_local(NULL);
306
307	local_irq_enable();  /* Interrupts have been off until now */
308
309	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
310
311	/* NOTREACHED */
312	panic("smp_callin() AAAAaaaaahhhh....\n");
313}
314
315/*
316 * Bring one cpu online.
317 */
318int smp_boot_one_cpu(int cpuid, struct task_struct *idle)
319{
320	const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
321	long timeout;
322
323	task_thread_info(idle)->cpu = cpuid;
324
325	/* Let _start know what logical CPU we're booting
326	** (offset into init_tasks[],cpu_data[])
327	*/
328	cpu_now_booting = cpuid;
329
330	/* 
331	** boot strap code needs to know the task address since
332	** it also contains the process stack.
333	*/
334	smp_init_current_idle_task = idle ;
335	mb();
336
337	printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);
338
339	/*
340	** This gets PDC to release the CPU from a very tight loop.
341	**
342	** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
343	** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which 
344	** is executed after receiving the rendezvous signal (an interrupt to 
345	** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the 
346	** contents of memory are valid."
347	*/
348	gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
349	mb();
350
351	/* 
352	 * OK, wait a bit for that CPU to finish staggering about. 
353	 * Slave will set a bit when it reaches smp_cpu_init().
354	 * Once the "monarch CPU" sees the bit change, it can move on.
355	 */
356	for (timeout = 0; timeout < 10000; timeout++) {
357		if(cpu_online(cpuid)) {
358			/* Which implies Slave has started up */
359			cpu_now_booting = 0;
360			smp_init_current_idle_task = NULL;
361			goto alive ;
362		}
363		udelay(100);
364		barrier();
365	}
366	printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
367	return -1;
368
369alive:
370	/* Remember the Slave data */
371	smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
372		cpuid, timeout * 100);
373	return 0;
374}
375
376void __init smp_prepare_boot_cpu(void)
377{
378	int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
379
380	/* Setup BSP mappings */
381	printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
382
383	set_cpu_online(bootstrap_processor, true);
384	set_cpu_present(bootstrap_processor, true);
385}
386
387
388
389/*
390** inventory.c:do_inventory() hasn't yet been run and thus we
391** don't 'discover' the additional CPUs until later.
392*/
393void __init smp_prepare_cpus(unsigned int max_cpus)
394{
395	int cpu;
396
397	for_each_possible_cpu(cpu)
398		spin_lock_init(&per_cpu(ipi_lock, cpu));
399
400	init_cpu_present(cpumask_of(0));
401
402	parisc_max_cpus = max_cpus;
403	if (!max_cpus)
404		printk(KERN_INFO "SMP mode deactivated.\n");
405}
406
407
408void smp_cpus_done(unsigned int cpu_max)
409{
410	return;
411}
412
413
414int __cpu_up(unsigned int cpu, struct task_struct *tidle)
415{
416	if (cpu != 0 && cpu < parisc_max_cpus && smp_boot_one_cpu(cpu, tidle))
417		return -ENOSYS;
418
419	return cpu_online(cpu) ? 0 : -ENOSYS;
420}
421
422#ifdef CONFIG_PROC_FS
423int setup_profiling_timer(unsigned int multiplier)
 
424{
425	return -EINVAL;
426}
427#endif
v4.6
 
  1/*
  2** SMP Support
  3**
  4** Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
  5** Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
  6** Copyright (C) 2001,2004 Grant Grundler <grundler@parisc-linux.org>
  7** 
  8** Lots of stuff stolen from arch/alpha/kernel/smp.c
  9** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^)
 10**
 11** Thanks to John Curry and Ullas Ponnadi. I learned a lot from their work.
 12** -grant (1/12/2001)
 13**
 14**	This program is free software; you can redistribute it and/or modify
 15**	it under the terms of the GNU General Public License as published by
 16**      the Free Software Foundation; either version 2 of the License, or
 17**      (at your option) any later version.
 18*/
 19#include <linux/types.h>
 20#include <linux/spinlock.h>
 21
 22#include <linux/kernel.h>
 23#include <linux/module.h>
 24#include <linux/sched.h>
 25#include <linux/init.h>
 26#include <linux/interrupt.h>
 27#include <linux/smp.h>
 28#include <linux/kernel_stat.h>
 29#include <linux/mm.h>
 30#include <linux/err.h>
 31#include <linux/delay.h>
 32#include <linux/bitops.h>
 33#include <linux/ftrace.h>
 34#include <linux/cpu.h>
 35
 36#include <linux/atomic.h>
 37#include <asm/current.h>
 38#include <asm/delay.h>
 39#include <asm/tlbflush.h>
 40
 41#include <asm/io.h>
 42#include <asm/irq.h>		/* for CPU_IRQ_REGION and friends */
 43#include <asm/mmu_context.h>
 44#include <asm/page.h>
 45#include <asm/pgtable.h>
 46#include <asm/pgalloc.h>
 47#include <asm/processor.h>
 48#include <asm/ptrace.h>
 49#include <asm/unistd.h>
 50#include <asm/cacheflush.h>
 51
 52#undef DEBUG_SMP
 53#ifdef DEBUG_SMP
 54static int smp_debug_lvl = 0;
 55#define smp_debug(lvl, printargs...)		\
 56		if (lvl >= smp_debug_lvl)	\
 57			printk(printargs);
 58#else
 59#define smp_debug(lvl, ...)	do { } while(0)
 60#endif /* DEBUG_SMP */
 61
 62volatile struct task_struct *smp_init_current_idle_task;
 63
 64/* track which CPU is booting */
 65static volatile int cpu_now_booting;
 66
 67static int parisc_max_cpus = 1;
 68
 69static DEFINE_PER_CPU(spinlock_t, ipi_lock);
 70
 71enum ipi_message_type {
 72	IPI_NOP=0,
 73	IPI_RESCHEDULE=1,
 74	IPI_CALL_FUNC,
 75	IPI_CPU_START,
 76	IPI_CPU_STOP,
 77	IPI_CPU_TEST
 78};
 79
 80
 81/********** SMP inter processor interrupt and communication routines */
 82
 83#undef PER_CPU_IRQ_REGION
 84#ifdef PER_CPU_IRQ_REGION
 85/* XXX REVISIT Ignore for now.
 86**    *May* need this "hook" to register IPI handler
 87**    once we have perCPU ExtIntr switch tables.
 88*/
 89static void
 90ipi_init(int cpuid)
 91{
 92#error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
 93
 94	if(cpu_online(cpuid) )
 95	{
 96		switch_to_idle_task(current);
 97	}
 98
 99	return;
100}
101#endif
102
103
104/*
105** Yoink this CPU from the runnable list... 
106**
107*/
108static void
109halt_processor(void) 
110{
111	/* REVISIT : redirect I/O Interrupts to another CPU? */
112	/* REVISIT : does PM *know* this CPU isn't available? */
113	set_cpu_online(smp_processor_id(), false);
114	local_irq_disable();
 
115	for (;;)
116		;
117}
118
119
120irqreturn_t __irq_entry
121ipi_interrupt(int irq, void *dev_id) 
122{
123	int this_cpu = smp_processor_id();
124	struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
125	unsigned long ops;
126	unsigned long flags;
127
128	for (;;) {
129		spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
130		spin_lock_irqsave(lock, flags);
131		ops = p->pending_ipi;
132		p->pending_ipi = 0;
133		spin_unlock_irqrestore(lock, flags);
134
135		mb(); /* Order bit clearing and data access. */
136
137		if (!ops)
138		    break;
139
140		while (ops) {
141			unsigned long which = ffz(~ops);
142
143			ops &= ~(1 << which);
144
145			switch (which) {
146			case IPI_NOP:
147				smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
148				break;
149				
150			case IPI_RESCHEDULE:
151				smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
152				inc_irq_stat(irq_resched_count);
153				scheduler_ipi();
154				break;
155
156			case IPI_CALL_FUNC:
157				smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
 
158				generic_smp_call_function_interrupt();
159				break;
160
161			case IPI_CPU_START:
162				smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
163				break;
164
165			case IPI_CPU_STOP:
166				smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
167				halt_processor();
168				break;
169
170			case IPI_CPU_TEST:
171				smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
172				break;
173
174			default:
175				printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
176					this_cpu, which);
177				return IRQ_NONE;
178			} /* Switch */
179		/* let in any pending interrupts */
180		local_irq_enable();
181		local_irq_disable();
182		} /* while (ops) */
183	}
184	return IRQ_HANDLED;
185}
186
187
188static inline void
189ipi_send(int cpu, enum ipi_message_type op)
190{
191	struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
192	spinlock_t *lock = &per_cpu(ipi_lock, cpu);
193	unsigned long flags;
194
195	spin_lock_irqsave(lock, flags);
196	p->pending_ipi |= 1 << op;
197	gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
198	spin_unlock_irqrestore(lock, flags);
199}
200
201static void
202send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
203{
204	int cpu;
205
206	for_each_cpu(cpu, mask)
207		ipi_send(cpu, op);
208}
209
210static inline void
211send_IPI_single(int dest_cpu, enum ipi_message_type op)
212{
213	BUG_ON(dest_cpu == NO_PROC_ID);
214
215	ipi_send(dest_cpu, op);
216}
217
218static inline void
219send_IPI_allbutself(enum ipi_message_type op)
220{
221	int i;
222	
223	for_each_online_cpu(i) {
224		if (i != smp_processor_id())
225			send_IPI_single(i, op);
226	}
227}
228
229
230inline void 
231smp_send_stop(void)	{ send_IPI_allbutself(IPI_CPU_STOP); }
232
233void 
234smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
235
236void
237smp_send_all_nop(void)
238{
239	send_IPI_allbutself(IPI_NOP);
240}
241
242void arch_send_call_function_ipi_mask(const struct cpumask *mask)
243{
244	send_IPI_mask(mask, IPI_CALL_FUNC);
245}
246
247void arch_send_call_function_single_ipi(int cpu)
248{
249	send_IPI_single(cpu, IPI_CALL_FUNC);
250}
251
252/*
253 * Called by secondaries to update state and initialize CPU registers.
254 */
255static void __init
256smp_cpu_init(int cpunum)
257{
258	extern int init_per_cpu(int);  /* arch/parisc/kernel/processor.c */
259	extern void init_IRQ(void);    /* arch/parisc/kernel/irq.c */
260	extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
261
262	/* Set modes and Enable floating point coprocessor */
263	(void) init_per_cpu(cpunum);
264
265	disable_sr_hashing();
266
267	mb();
268
269	/* Well, support 2.4 linux scheme as well. */
270	if (cpu_online(cpunum))	{
271		extern void machine_halt(void); /* arch/parisc.../process.c */
272
273		printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
274		machine_halt();
275	}
276
277	notify_cpu_starting(cpunum);
278
279	set_cpu_online(cpunum, true);
280
281	/* Initialise the idle task for this CPU */
282	atomic_inc(&init_mm.mm_count);
283	current->active_mm = &init_mm;
284	BUG_ON(current->mm);
285	enter_lazy_tlb(&init_mm, current);
286
287	init_IRQ();   /* make sure no IRQs are enabled or pending */
288	start_cpu_itimer();
289}
290
291
292/*
293 * Slaves start using C here. Indirectly called from smp_slave_stext.
294 * Do what start_kernel() and main() do for boot strap processor (aka monarch)
295 */
296void __init smp_callin(void)
297{
298	int slave_id = cpu_now_booting;
299
 
 
 
 
 
300	smp_cpu_init(slave_id);
301	preempt_disable();
302
303	flush_cache_all_local(); /* start with known state */
304	flush_tlb_all_local(NULL);
305
306	local_irq_enable();  /* Interrupts have been off until now */
307
308	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
309
310	/* NOTREACHED */
311	panic("smp_callin() AAAAaaaaahhhh....\n");
312}
313
314/*
315 * Bring one cpu online.
316 */
317int smp_boot_one_cpu(int cpuid, struct task_struct *idle)
318{
319	const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
320	long timeout;
321
322	task_thread_info(idle)->cpu = cpuid;
323
324	/* Let _start know what logical CPU we're booting
325	** (offset into init_tasks[],cpu_data[])
326	*/
327	cpu_now_booting = cpuid;
328
329	/* 
330	** boot strap code needs to know the task address since
331	** it also contains the process stack.
332	*/
333	smp_init_current_idle_task = idle ;
334	mb();
335
336	printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);
337
338	/*
339	** This gets PDC to release the CPU from a very tight loop.
340	**
341	** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
342	** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which 
343	** is executed after receiving the rendezvous signal (an interrupt to 
344	** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the 
345	** contents of memory are valid."
346	*/
347	gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
348	mb();
349
350	/* 
351	 * OK, wait a bit for that CPU to finish staggering about. 
352	 * Slave will set a bit when it reaches smp_cpu_init().
353	 * Once the "monarch CPU" sees the bit change, it can move on.
354	 */
355	for (timeout = 0; timeout < 10000; timeout++) {
356		if(cpu_online(cpuid)) {
357			/* Which implies Slave has started up */
358			cpu_now_booting = 0;
359			smp_init_current_idle_task = NULL;
360			goto alive ;
361		}
362		udelay(100);
363		barrier();
364	}
365	printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
366	return -1;
367
368alive:
369	/* Remember the Slave data */
370	smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
371		cpuid, timeout * 100);
372	return 0;
373}
374
375void __init smp_prepare_boot_cpu(void)
376{
377	int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
378
379	/* Setup BSP mappings */
380	printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
381
382	set_cpu_online(bootstrap_processor, true);
383	set_cpu_present(bootstrap_processor, true);
384}
385
386
387
388/*
389** inventory.c:do_inventory() hasn't yet been run and thus we
390** don't 'discover' the additional CPUs until later.
391*/
392void __init smp_prepare_cpus(unsigned int max_cpus)
393{
394	int cpu;
395
396	for_each_possible_cpu(cpu)
397		spin_lock_init(&per_cpu(ipi_lock, cpu));
398
399	init_cpu_present(cpumask_of(0));
400
401	parisc_max_cpus = max_cpus;
402	if (!max_cpus)
403		printk(KERN_INFO "SMP mode deactivated.\n");
404}
405
406
407void smp_cpus_done(unsigned int cpu_max)
408{
409	return;
410}
411
412
413int __cpu_up(unsigned int cpu, struct task_struct *tidle)
414{
415	if (cpu != 0 && cpu < parisc_max_cpus)
416		smp_boot_one_cpu(cpu, tidle);
417
418	return cpu_online(cpu) ? 0 : -ENOSYS;
419}
420
421#ifdef CONFIG_PROC_FS
422int __init
423setup_profiling_timer(unsigned int multiplier)
424{
425	return -EINVAL;
426}
427#endif