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/config.h> 14 #include <linux/cache.h> 15 #include <linux/cpumask.h> 16 #include <linux/delay.h> 17 #include <linux/init.h> 18 #include <linux/interrupt.h> 19 #include <linux/spinlock.h> 20 #include <linux/threads.h> 21 #include <linux/module.h> 22 #include <linux/time.h> 23 #include <linux/timex.h> 24 #include <linux/sched.h> 25 #include <linux/module.h> 26 27 #include <asm/atomic.h> 28 #include <asm/processor.h> 29 #include <asm/system.h> 30 #include <asm/mmu_context.h> 31 #include <asm/smp.h> 32 33 /* 34 * This was written with the Sega Saturn (SMP SH-2 7604) in mind, 35 * but is designed to be usable regardless if there's an MMU 36 * present or not. 37 */ 38 struct sh_cpuinfo cpu_data[NR_CPUS]; 39 40 extern void per_cpu_trap_init(void); 41 42 cpumask_t cpu_possible_map; 43 EXPORT_SYMBOL(cpu_possible_map); 44 45 cpumask_t 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 tsk->thread_info->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 = smp_processor_id(); 116 117 atomic_inc(&init_mm.mm_count); 118 current->active_mm = &init_mm; 119 120 smp_store_cpu_info(cpu); 121 122 __smp_slave_init(cpu); 123 per_cpu_trap_init(); 124 125 atomic_inc(&cpus_booted); 126 127 cpu_idle(); 128 return 0; 129 } 130 131 void __init smp_cpus_done(unsigned int max_cpus) 132 { 133 smp_mb(); 134 } 135 136 void smp_send_reschedule(int cpu) 137 { 138 __smp_send_ipi(cpu, SMP_MSG_RESCHEDULE); 139 } 140 141 static void stop_this_cpu(void *unused) 142 { 143 cpu_clear(smp_processor_id(), cpu_online_map); 144 local_irq_disable(); 145 146 for (;;) 147 cpu_relax(); 148 } 149 150 void smp_send_stop(void) 151 { 152 smp_call_function(stop_this_cpu, 0, 1, 0); 153 } 154 155 156 struct smp_fn_call_struct smp_fn_call = { 157 .lock = SPIN_LOCK_UNLOCKED, 158 .finished = ATOMIC_INIT(0), 159 }; 160 161 /* 162 * The caller of this wants the passed function to run on every cpu. If wait 163 * is set, wait until all cpus have finished the function before returning. 164 * The lock is here to protect the call structure. 165 * You must not call this function with disabled interrupts or from a 166 * hardware interrupt handler or from a bottom half handler. 167 */ 168 int smp_call_function(void (*func)(void *info), void *info, int retry, int wait) 169 { 170 unsigned int nr_cpus = atomic_read(&cpus_booted); 171 int i; 172 173 if (nr_cpus < 2) 174 return 0; 175 176 /* Can deadlock when called with interrupts disabled */ 177 WARN_ON(irqs_disabled()); 178 179 spin_lock(&smp_fn_call.lock); 180 181 atomic_set(&smp_fn_call.finished, 0); 182 smp_fn_call.fn = func; 183 smp_fn_call.data = info; 184 185 for (i = 0; i < nr_cpus; i++) 186 if (i != smp_processor_id()) 187 __smp_call_function(i); 188 189 if (wait) 190 while (atomic_read(&smp_fn_call.finished) != (nr_cpus - 1)); 191 192 spin_unlock(&smp_fn_call.lock); 193 194 return 0; 195 } 196 197 /* Not really SMP stuff ... */ 198 int setup_profiling_timer(unsigned int multiplier) 199 { 200 return 0; 201 } 202 203