![Kyle McMartin](/assets/img/avatar_default.png)
It's been unfinished and broken long enough, and I have some ideas on how to do it more cleanly. Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
578 lines
13 KiB
C
578 lines
13 KiB
C
/*
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** SMP Support
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**
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** Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
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** Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
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** Copyright (C) 2001,2004 Grant Grundler <grundler@parisc-linux.org>
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**
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** Lots of stuff stolen from arch/alpha/kernel/smp.c
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** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^)
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**
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** Thanks to John Curry and Ullas Ponnadi. I learned a lot from their work.
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** -grant (1/12/2001)
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**
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** This program is free software; you can redistribute it and/or modify
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** it under the terms of the GNU General Public License as published by
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** the Free Software Foundation; either version 2 of the License, or
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** (at your option) any later version.
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*/
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#include <linux/types.h>
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#include <linux/spinlock.h>
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#include <linux/slab.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/smp.h>
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#include <linux/kernel_stat.h>
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#include <linux/mm.h>
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#include <linux/err.h>
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#include <linux/delay.h>
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#include <linux/bitops.h>
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#include <asm/system.h>
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#include <asm/atomic.h>
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#include <asm/current.h>
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#include <asm/delay.h>
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#include <asm/tlbflush.h>
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#include <asm/io.h>
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#include <asm/irq.h> /* for CPU_IRQ_REGION and friends */
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#include <asm/mmu_context.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <asm/pgalloc.h>
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#include <asm/processor.h>
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#include <asm/ptrace.h>
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#include <asm/unistd.h>
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#include <asm/cacheflush.h>
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#undef DEBUG_SMP
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#ifdef DEBUG_SMP
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static int smp_debug_lvl = 0;
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#define smp_debug(lvl, printargs...) \
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if (lvl >= smp_debug_lvl) \
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printk(printargs);
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#else
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#define smp_debug(lvl, ...)
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#endif /* DEBUG_SMP */
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DEFINE_SPINLOCK(smp_lock);
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volatile struct task_struct *smp_init_current_idle_task;
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static volatile int cpu_now_booting __read_mostly = 0; /* track which CPU is booting */
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static int parisc_max_cpus __read_mostly = 1;
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/* online cpus are ones that we've managed to bring up completely
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* possible cpus are all valid cpu
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* present cpus are all detected cpu
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*
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* On startup we bring up the "possible" cpus. Since we discover
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* CPUs later, we add them as hotplug, so the possible cpu mask is
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* empty in the beginning.
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*/
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cpumask_t cpu_online_map __read_mostly = CPU_MASK_NONE; /* Bitmap of online CPUs */
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cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; /* Bitmap of Present CPUs */
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EXPORT_SYMBOL(cpu_online_map);
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EXPORT_SYMBOL(cpu_possible_map);
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DEFINE_PER_CPU(spinlock_t, ipi_lock) = SPIN_LOCK_UNLOCKED;
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struct smp_call_struct {
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void (*func) (void *info);
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void *info;
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long wait;
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atomic_t unstarted_count;
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atomic_t unfinished_count;
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};
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static volatile struct smp_call_struct *smp_call_function_data;
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enum ipi_message_type {
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IPI_NOP=0,
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IPI_RESCHEDULE=1,
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IPI_CALL_FUNC,
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IPI_CPU_START,
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IPI_CPU_STOP,
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IPI_CPU_TEST
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};
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/********** SMP inter processor interrupt and communication routines */
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#undef PER_CPU_IRQ_REGION
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#ifdef PER_CPU_IRQ_REGION
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/* XXX REVISIT Ignore for now.
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** *May* need this "hook" to register IPI handler
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** once we have perCPU ExtIntr switch tables.
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*/
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static void
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ipi_init(int cpuid)
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{
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#error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
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if(cpu_online(cpuid) )
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{
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switch_to_idle_task(current);
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}
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return;
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}
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#endif
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/*
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** Yoink this CPU from the runnable list...
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**
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*/
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static void
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halt_processor(void)
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{
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/* REVISIT : redirect I/O Interrupts to another CPU? */
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/* REVISIT : does PM *know* this CPU isn't available? */
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cpu_clear(smp_processor_id(), cpu_online_map);
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local_irq_disable();
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for (;;)
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;
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}
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irqreturn_t
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ipi_interrupt(int irq, void *dev_id)
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{
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int this_cpu = smp_processor_id();
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struct cpuinfo_parisc *p = &cpu_data[this_cpu];
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unsigned long ops;
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unsigned long flags;
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/* Count this now; we may make a call that never returns. */
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p->ipi_count++;
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mb(); /* Order interrupt and bit testing. */
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for (;;) {
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spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
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spin_lock_irqsave(lock, flags);
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ops = p->pending_ipi;
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p->pending_ipi = 0;
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spin_unlock_irqrestore(lock, flags);
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mb(); /* Order bit clearing and data access. */
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if (!ops)
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break;
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while (ops) {
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unsigned long which = ffz(~ops);
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ops &= ~(1 << which);
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switch (which) {
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case IPI_NOP:
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smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
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break;
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case IPI_RESCHEDULE:
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smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
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/*
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* Reschedule callback. Everything to be
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* done is done by the interrupt return path.
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*/
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break;
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case IPI_CALL_FUNC:
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smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
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{
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volatile struct smp_call_struct *data;
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void (*func)(void *info);
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void *info;
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int wait;
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data = smp_call_function_data;
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func = data->func;
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info = data->info;
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wait = data->wait;
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mb();
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atomic_dec ((atomic_t *)&data->unstarted_count);
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/* At this point, *data can't
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* be relied upon.
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*/
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(*func)(info);
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/* Notify the sending CPU that the
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* task is done.
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*/
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mb();
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if (wait)
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atomic_dec ((atomic_t *)&data->unfinished_count);
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}
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break;
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case IPI_CPU_START:
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smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
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break;
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case IPI_CPU_STOP:
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smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
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halt_processor();
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break;
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case IPI_CPU_TEST:
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smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
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break;
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default:
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printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
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this_cpu, which);
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return IRQ_NONE;
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} /* Switch */
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/* let in any pending interrupts */
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local_irq_enable();
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local_irq_disable();
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} /* while (ops) */
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}
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return IRQ_HANDLED;
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}
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static inline void
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ipi_send(int cpu, enum ipi_message_type op)
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{
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struct cpuinfo_parisc *p = &cpu_data[cpu];
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spinlock_t *lock = &per_cpu(ipi_lock, cpu);
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unsigned long flags;
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spin_lock_irqsave(lock, flags);
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p->pending_ipi |= 1 << op;
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gsc_writel(IPI_IRQ - CPU_IRQ_BASE, cpu_data[cpu].hpa);
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spin_unlock_irqrestore(lock, flags);
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}
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static inline void
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send_IPI_single(int dest_cpu, enum ipi_message_type op)
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{
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if (dest_cpu == NO_PROC_ID) {
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BUG();
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return;
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}
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ipi_send(dest_cpu, op);
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}
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static inline void
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send_IPI_allbutself(enum ipi_message_type op)
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{
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int i;
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for_each_online_cpu(i) {
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if (i != smp_processor_id())
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send_IPI_single(i, op);
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}
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}
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inline void
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smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); }
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static inline void
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smp_send_start(void) { send_IPI_allbutself(IPI_CPU_START); }
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void
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smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
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void
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smp_send_all_nop(void)
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{
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send_IPI_allbutself(IPI_NOP);
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}
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/**
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* Run a function on all other CPUs.
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* <func> The function to run. This must be fast and non-blocking.
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* <info> An arbitrary pointer to pass to the function.
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* <retry> If true, keep retrying until ready.
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* <wait> If true, wait until function has completed on other CPUs.
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* [RETURNS] 0 on success, else a negative status code.
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*
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* Does not return until remote CPUs are nearly ready to execute <func>
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* or have executed.
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*/
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int
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smp_call_function (void (*func) (void *info), void *info, int retry, int wait)
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{
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struct smp_call_struct data;
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unsigned long timeout;
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static DEFINE_SPINLOCK(lock);
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int retries = 0;
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if (num_online_cpus() < 2)
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return 0;
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/* Can deadlock when called with interrupts disabled */
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WARN_ON(irqs_disabled());
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/* can also deadlock if IPIs are disabled */
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WARN_ON((get_eiem() & (1UL<<(CPU_IRQ_MAX - IPI_IRQ))) == 0);
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data.func = func;
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data.info = info;
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data.wait = wait;
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atomic_set(&data.unstarted_count, num_online_cpus() - 1);
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atomic_set(&data.unfinished_count, num_online_cpus() - 1);
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if (retry) {
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spin_lock (&lock);
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while (smp_call_function_data != 0)
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barrier();
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}
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else {
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spin_lock (&lock);
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if (smp_call_function_data) {
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spin_unlock (&lock);
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return -EBUSY;
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}
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}
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smp_call_function_data = &data;
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spin_unlock (&lock);
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/* Send a message to all other CPUs and wait for them to respond */
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send_IPI_allbutself(IPI_CALL_FUNC);
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retry:
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/* Wait for response */
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timeout = jiffies + HZ;
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while ( (atomic_read (&data.unstarted_count) > 0) &&
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time_before (jiffies, timeout) )
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barrier ();
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if (atomic_read (&data.unstarted_count) > 0) {
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printk(KERN_CRIT "SMP CALL FUNCTION TIMED OUT! (cpu=%d), try %d\n",
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smp_processor_id(), ++retries);
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goto retry;
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}
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/* We either got one or timed out. Release the lock */
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mb();
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smp_call_function_data = NULL;
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while (wait && atomic_read (&data.unfinished_count) > 0)
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barrier ();
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return 0;
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}
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EXPORT_SYMBOL(smp_call_function);
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/*
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* Flush all other CPU's tlb and then mine. Do this with on_each_cpu()
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* as we want to ensure all TLB's flushed before proceeding.
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*/
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void
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smp_flush_tlb_all(void)
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{
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on_each_cpu(flush_tlb_all_local, NULL, 1, 1);
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}
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/*
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* Called by secondaries to update state and initialize CPU registers.
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*/
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static void __init
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smp_cpu_init(int cpunum)
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{
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extern int init_per_cpu(int); /* arch/parisc/kernel/processor.c */
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extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */
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extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
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/* Set modes and Enable floating point coprocessor */
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(void) init_per_cpu(cpunum);
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disable_sr_hashing();
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mb();
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/* Well, support 2.4 linux scheme as well. */
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if (cpu_test_and_set(cpunum, cpu_online_map))
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{
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extern void machine_halt(void); /* arch/parisc.../process.c */
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printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
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machine_halt();
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}
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/* Initialise the idle task for this CPU */
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atomic_inc(&init_mm.mm_count);
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current->active_mm = &init_mm;
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if(current->mm)
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BUG();
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enter_lazy_tlb(&init_mm, current);
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init_IRQ(); /* make sure no IRQs are enabled or pending */
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start_cpu_itimer();
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}
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/*
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* Slaves start using C here. Indirectly called from smp_slave_stext.
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* Do what start_kernel() and main() do for boot strap processor (aka monarch)
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*/
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void __init smp_callin(void)
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{
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int slave_id = cpu_now_booting;
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smp_cpu_init(slave_id);
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preempt_disable();
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flush_cache_all_local(); /* start with known state */
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flush_tlb_all_local(NULL);
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local_irq_enable(); /* Interrupts have been off until now */
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cpu_idle(); /* Wait for timer to schedule some work */
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/* NOTREACHED */
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panic("smp_callin() AAAAaaaaahhhh....\n");
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}
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/*
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* Bring one cpu online.
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*/
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int __cpuinit smp_boot_one_cpu(int cpuid)
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{
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struct task_struct *idle;
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long timeout;
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/*
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* Create an idle task for this CPU. Note the address wed* give
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* to kernel_thread is irrelevant -- it's going to start
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* where OS_BOOT_RENDEVZ vector in SAL says to start. But
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* this gets all the other task-y sort of data structures set
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* up like we wish. We need to pull the just created idle task
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* off the run queue and stuff it into the init_tasks[] array.
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* Sheesh . . .
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*/
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idle = fork_idle(cpuid);
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if (IS_ERR(idle))
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panic("SMP: fork failed for CPU:%d", cpuid);
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task_thread_info(idle)->cpu = cpuid;
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/* Let _start know what logical CPU we're booting
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** (offset into init_tasks[],cpu_data[])
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*/
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cpu_now_booting = cpuid;
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/*
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** boot strap code needs to know the task address since
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** it also contains the process stack.
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*/
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smp_init_current_idle_task = idle ;
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mb();
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printk("Releasing cpu %d now, hpa=%lx\n", cpuid, cpu_data[cpuid].hpa);
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/*
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** This gets PDC to release the CPU from a very tight loop.
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**
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** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
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** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
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** is executed after receiving the rendezvous signal (an interrupt to
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** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
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** contents of memory are valid."
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*/
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gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, cpu_data[cpuid].hpa);
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mb();
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/*
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* OK, wait a bit for that CPU to finish staggering about.
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* Slave will set a bit when it reaches smp_cpu_init().
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* Once the "monarch CPU" sees the bit change, it can move on.
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*/
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for (timeout = 0; timeout < 10000; timeout++) {
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if(cpu_online(cpuid)) {
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/* Which implies Slave has started up */
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cpu_now_booting = 0;
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smp_init_current_idle_task = NULL;
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goto alive ;
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}
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udelay(100);
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barrier();
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}
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put_task_struct(idle);
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idle = NULL;
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printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
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return -1;
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alive:
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/* Remember the Slave data */
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smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
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cpuid, timeout * 100);
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return 0;
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}
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void __devinit smp_prepare_boot_cpu(void)
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{
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int bootstrap_processor=cpu_data[0].cpuid; /* CPU ID of BSP */
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/* Setup BSP mappings */
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printk("SMP: bootstrap CPU ID is %d\n",bootstrap_processor);
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cpu_set(bootstrap_processor, cpu_online_map);
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cpu_set(bootstrap_processor, cpu_present_map);
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}
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/*
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|
** inventory.c:do_inventory() hasn't yet been run and thus we
|
|
** don't 'discover' the additional CPUs until later.
|
|
*/
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|
void __init smp_prepare_cpus(unsigned int max_cpus)
|
|
{
|
|
cpus_clear(cpu_present_map);
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|
cpu_set(0, cpu_present_map);
|
|
|
|
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 __cpuinit __cpu_up(unsigned int cpu)
|
|
{
|
|
if (cpu != 0 && cpu < parisc_max_cpus)
|
|
smp_boot_one_cpu(cpu);
|
|
|
|
return cpu_online(cpu) ? 0 : -ENOSYS;
|
|
}
|
|
|
|
#ifdef CONFIG_PROC_FS
|
|
int __init
|
|
setup_profiling_timer(unsigned int multiplier)
|
|
{
|
|
return -EINVAL;
|
|
}
|
|
#endif
|