arch/sh/kernel/smp.c

   1 /*
   2  * arch/sh/kernel/smp.c
   3  *
   4  * SMP support for the SuperH processors.
   5  *
   6  * Copyright (C) 2002, 2003 Paul Mundt
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by the
  10  * Free Software Foundation; either version 2 of the License, or (at your
  11  * option) any later version.
  12  */
  13 #include <linux/cache.h>
  14 #include <linux/cpumask.h>
  15 #include <linux/delay.h>
  16 #include <linux/init.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/threads.h>
  20 #include <linux/module.h>
  21 #include <linux/time.h>
  22 #include <linux/timex.h>
  23 #include <linux/sched.h>
  24 #include <linux/module.h>
  25
  26 #include <asm/atomic.h>
  27 #include <asm/processor.h>
  28 #include <asm/system.h>
  29 #include <asm/mmu_context.h>
  30 #include <asm/smp.h>
  31
  32 /*
  33  * This was written with the Sega Saturn (SMP SH-2 7604) in mind,
  34  * but is designed to be usable regardless if there's an MMU
  35  * present or not.
  36  */
  37 struct sh_cpuinfo cpu_data[NR_CPUS];
  38
  39 extern void per_cpu_trap_init(void);
  40
  41 cpumask_t cpu_possible_map;
  42 EXPORT_SYMBOL(cpu_possible_map);
  43
  44 cpumask_t cpu_online_map;
  45 static atomic_t cpus_booted = ATOMIC_INIT(0);
  46
  47 /* These are defined by the board-specific code. */
  48
  49 /*
  50  * Cause the function described by call_data to be executed on the passed
  51  * cpu.  When the function has finished, increment the finished field of
  52  * call_data.
  53  */
  54 void __smp_send_ipi(unsigned int cpu, unsigned int action);
  55
  56 /*
  57  * Find the number of available processors
  58  */
  59 unsigned int __smp_probe_cpus(void);
  60
  61 /*
  62  * Start a particular processor
  63  */
  64 void __smp_slave_init(unsigned int cpu);
  65
  66 /*
  67  * Run specified function on a particular processor.
  68  */
  69 void __smp_call_function(unsigned int cpu);
  70
  71 static inline void __init smp_store_cpu_info(unsigned int cpu)
  72 {
  73         cpu_data[cpu].loops_per_jiffy = loops_per_jiffy;
  74 }
  75
  76 void __init smp_prepare_cpus(unsigned int max_cpus)
  77 {
  78         unsigned int cpu = smp_processor_id();
  79         int i;
  80
  81         atomic_set(&cpus_booted, 1);
  82         smp_store_cpu_info(cpu);
  83
  84         for (i = 0; i < __smp_probe_cpus(); i++)
  85                 cpu_set(i, cpu_possible_map);
  86 }
  87
  88 void __devinit smp_prepare_boot_cpu(void)
  89 {
  90         unsigned int cpu = smp_processor_id();
  91
  92         cpu_set(cpu, cpu_online_map);
  93         cpu_set(cpu, cpu_possible_map);
  94 }
  95
  96 int __cpu_up(unsigned int cpu)
  97 {
  98         struct task_struct *tsk;
  99
 100         tsk = fork_idle(cpu);
 101
 102         if (IS_ERR(tsk))
 103                 panic("Failed forking idle task for cpu %d\n", cpu);
 104
 105         task_thread_info(tsk)->cpu = cpu;
 106
 107         cpu_set(cpu, cpu_online_map);
 108
 109         return 0;
 110 }
 111
 112 int start_secondary(void *unused)
 113 {
 114         unsigned int cpu;
 115
 116         cpu = smp_processor_id();
 117
 118         atomic_inc(&init_mm.mm_count);
 119         current->active_mm = &init_mm;
 120
 121         smp_store_cpu_info(cpu);
 122
 123         __smp_slave_init(cpu);
 124         preempt_disable();
 125         per_cpu_trap_init();
 126
 127         atomic_inc(&cpus_booted);
 128
 129         cpu_idle();
 130         return 0;
 131 }
 132
 133 void __init smp_cpus_done(unsigned int max_cpus)
 134 {
 135         smp_mb();
 136 }
 137
 138 void smp_send_reschedule(int cpu)
 139 {
 140         __smp_send_ipi(cpu, SMP_MSG_RESCHEDULE);
 141 }
 142
 143 static void stop_this_cpu(void *unused)
 144 {
 145         cpu_clear(smp_processor_id(), cpu_online_map);
 146         local_irq_disable();
 147
 148         for (;;)
 149                 cpu_relax();
 150 }
 151
 152 void smp_send_stop(void)
 153 {
 154         smp_call_function(stop_this_cpu, 0, 1, 0);
 155 }
 156
 157
 158 struct smp_fn_call_struct smp_fn_call = {
 159         .lock           = SPIN_LOCK_UNLOCKED,
 160         .finished       = ATOMIC_INIT(0),
 161 };
 162
 163 /*
 164  * The caller of this wants the passed function to run on every cpu.  If wait
 165  * is set, wait until all cpus have finished the function before returning.
 166  * The lock is here to protect the call structure.
 167  * You must not call this function with disabled interrupts or from a
 168  * hardware interrupt handler or from a bottom half handler.
 169  */
 170 int smp_call_function(void (*func)(void *info), void *info, int retry, int wait)
 171 {
 172         unsigned int nr_cpus = atomic_read(&cpus_booted);
 173         int i;
 174
 175         if (nr_cpus < 2)
 176                 return 0;
 177
 178         /* Can deadlock when called with interrupts disabled */
 179         WARN_ON(irqs_disabled());
 180
 181         spin_lock(&smp_fn_call.lock);
 182
 183         atomic_set(&smp_fn_call.finished, 0);
 184         smp_fn_call.fn = func;
 185         smp_fn_call.data = info;
 186
 187         for (i = 0; i < nr_cpus; i++)
 188                 if (i != smp_processor_id())
 189                         __smp_call_function(i);
 190
 191         if (wait)
 192                 while (atomic_read(&smp_fn_call.finished) != (nr_cpus - 1));
 193
 194         spin_unlock(&smp_fn_call.lock);
 195
 196         return 0;
 197 }
 198
 199 /* Not really SMP stuff ... */
 200 int setup_profiling_timer(unsigned int multiplier)
 201 {
 202         return 0;
 203 }
 204