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 EXPORT_SYMBOL(cpu_online_map);
  46 static atomic_t cpus_booted = ATOMIC_INIT(0);
  47
  48 /* These are defined by the board-specific code. */
  49
  50 /*
  51  * Cause the function described by call_data to be executed on the passed
  52  * cpu.  When the function has finished, increment the finished field of
  53  * call_data.
  54  */
  55 void __smp_send_ipi(unsigned int cpu, unsigned int action);
  56
  57 /*
  58  * Find the number of available processors
  59  */
  60 unsigned int __smp_probe_cpus(void);
  61
  62 /*
  63  * Start a particular processor
  64  */
  65 void __smp_slave_init(unsigned int cpu);
  66
  67 /*
  68  * Run specified function on a particular processor.
  69  */
  70 void __smp_call_function(unsigned int cpu);
  71
  72 static inline void __init smp_store_cpu_info(unsigned int cpu)
  73 {
  74         cpu_data[cpu].loops_per_jiffy = loops_per_jiffy;
  75 }
  76
  77 void __init smp_prepare_cpus(unsigned int max_cpus)
  78 {
  79         unsigned int cpu = smp_processor_id();
  80         int i;
  81
  82         atomic_set(&cpus_booted, 1);
  83         smp_store_cpu_info(cpu);
  84
  85         for (i = 0; i < __smp_probe_cpus(); i++)
  86                 cpu_set(i, cpu_possible_map);
  87 }
  88
  89 void __devinit smp_prepare_boot_cpu(void)
  90 {
  91         unsigned int cpu = smp_processor_id();
  92
  93         cpu_set(cpu, cpu_online_map);
  94         cpu_set(cpu, cpu_possible_map);
  95 }
  96
  97 int __cpu_up(unsigned int cpu)
  98 {
  99         struct task_struct *tsk;
 100
 101         tsk = fork_idle(cpu);
 102
 103         if (IS_ERR(tsk))
 104                 panic("Failed forking idle task for cpu %d\n", cpu);
 105
 106         task_thread_info(tsk)->cpu = cpu;
 107
 108         cpu_set(cpu, cpu_online_map);
 109
 110         return 0;
 111 }
 112
 113 int start_secondary(void *unused)
 114 {
 115         unsigned int cpu;
 116
 117         cpu = smp_processor_id();
 118
 119         atomic_inc(&init_mm.mm_count);
 120         current->active_mm = &init_mm;
 121
 122         smp_store_cpu_info(cpu);
 123
 124         __smp_slave_init(cpu);
 125         preempt_disable();
 126         per_cpu_trap_init();
 127
 128         atomic_inc(&cpus_booted);
 129
 130         cpu_idle();
 131         return 0;
 132 }
 133
 134 void __init smp_cpus_done(unsigned int max_cpus)
 135 {
 136         smp_mb();
 137 }
 138
 139 void smp_send_reschedule(int cpu)
 140 {
 141         __smp_send_ipi(cpu, SMP_MSG_RESCHEDULE);
 142 }
 143
 144 static void stop_this_cpu(void *unused)
 145 {
 146         cpu_clear(smp_processor_id(), cpu_online_map);
 147         local_irq_disable();
 148
 149         for (;;)
 150                 cpu_relax();
 151 }
 152
 153 void smp_send_stop(void)
 154 {
 155         smp_call_function(stop_this_cpu, 0, 1, 0);
 156 }
 157
 158
 159 struct smp_fn_call_struct smp_fn_call = {
 160         .lock           = SPIN_LOCK_UNLOCKED,
 161         .finished       = ATOMIC_INIT(0),
 162 };
 163
 164 /*
 165  * The caller of this wants the passed function to run on every cpu.  If wait
 166  * is set, wait until all cpus have finished the function before returning.
 167  * The lock is here to protect the call structure.
 168  * You must not call this function with disabled interrupts or from a
 169  * hardware interrupt handler or from a bottom half handler.
 170  */
 171 int smp_call_function(void (*func)(void *info), void *info, int retry, int wait)
 172 {
 173         unsigned int nr_cpus = atomic_read(&cpus_booted);
 174         int i;
 175
 176         if (nr_cpus < 2)
 177                 return 0;
 178
 179         /* Can deadlock when called with interrupts disabled */
 180         WARN_ON(irqs_disabled());
 181
 182         spin_lock(&smp_fn_call.lock);
 183
 184         atomic_set(&smp_fn_call.finished, 0);
 185         smp_fn_call.fn = func;
 186         smp_fn_call.data = info;
 187
 188         for (i = 0; i < nr_cpus; i++)
 189                 if (i != smp_processor_id())
 190                         __smp_call_function(i);
 191
 192         if (wait)
 193                 while (atomic_read(&smp_fn_call.finished) != (nr_cpus - 1));
 194
 195         spin_unlock(&smp_fn_call.lock);
 196
 197         return 0;
 198 }
 199
 200 /* Not really SMP stuff ... */
 201 int setup_profiling_timer(unsigned int multiplier)
 202 {
 203         return 0;
 204 }
 205