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 14 #include <linux/err.h> 15 #include <linux/cache.h> 16 #include <linux/cpumask.h> 17 #include <linux/delay.h> 18 #include <linux/init.h> 19 #include <linux/interrupt.h> 20 #include <linux/spinlock.h> 21 #include <linux/threads.h> 22 #include <linux/module.h> 23 #include <linux/time.h> 24 #include <linux/timex.h> 25 #include <linux/sched.h> 26 #include <linux/module.h> 27 28 #include <asm/atomic.h> 29 #include <asm/processor.h> 30 #include <asm/system.h> 31 #include <asm/mmu_context.h> 32 #include <asm/smp.h> 33 34 /* 35 * This was written with the Sega Saturn (SMP SH-2 7604) in mind, 36 * but is designed to be usable regardless if there's an MMU 37 * present or not. 38 */ 39 struct sh_cpuinfo cpu_data[NR_CPUS]; 40 41 extern void per_cpu_trap_init(void); 42 43 cpumask_t cpu_possible_map; 44 EXPORT_SYMBOL(cpu_possible_map); 45 46 cpumask_t cpu_online_map; 47 EXPORT_SYMBOL(cpu_online_map); 48 static atomic_t cpus_booted = ATOMIC_INIT(0); 49 50 /* These are defined by the board-specific code. */ 51 52 /* 53 * Cause the function described by call_data to be executed on the passed 54 * cpu. When the function has finished, increment the finished field of 55 * call_data. 56 */ 57 void __smp_send_ipi(unsigned int cpu, unsigned int action); 58 59 /* 60 * Find the number of available processors 61 */ 62 unsigned int __smp_probe_cpus(void); 63 64 /* 65 * Start a particular processor 66 */ 67 void __smp_slave_init(unsigned int cpu); 68 69 /* 70 * Run specified function on a particular processor. 71 */ 72 void __smp_call_function(unsigned int cpu); 73 74 static inline void __init smp_store_cpu_info(unsigned int cpu) 75 { 76 cpu_data[cpu].loops_per_jiffy = loops_per_jiffy; 77 } 78 79 void __init smp_prepare_cpus(unsigned int max_cpus) 80 { 81 unsigned int cpu = smp_processor_id(); 82 int i; 83 84 atomic_set(&cpus_booted, 1); 85 smp_store_cpu_info(cpu); 86 87 for (i = 0; i < __smp_probe_cpus(); i++) 88 cpu_set(i, cpu_possible_map); 89 } 90 91 void __devinit smp_prepare_boot_cpu(void) 92 { 93 unsigned int cpu = smp_processor_id(); 94 95 cpu_set(cpu, cpu_online_map); 96 cpu_set(cpu, cpu_possible_map); 97 } 98 99 int __cpu_up(unsigned int cpu) 100 { 101 struct task_struct *tsk; 102 103 tsk = fork_idle(cpu); 104 105 if (IS_ERR(tsk)) 106 panic("Failed forking idle task for cpu %d\n", cpu); 107 108 task_thread_info(tsk)->cpu = cpu; 109 110 cpu_set(cpu, cpu_online_map); 111 112 return 0; 113 } 114 115 int start_secondary(void *unused) 116 { 117 unsigned int cpu; 118 119 cpu = smp_processor_id(); 120 121 atomic_inc(&init_mm.mm_count); 122 current->active_mm = &init_mm; 123 124 smp_store_cpu_info(cpu); 125 126 __smp_slave_init(cpu); 127 preempt_disable(); 128 per_cpu_trap_init(); 129 130 atomic_inc(&cpus_booted); 131 132 cpu_idle(); 133 return 0; 134 } 135 136 void __init smp_cpus_done(unsigned int max_cpus) 137 { 138 smp_mb(); 139 } 140 141 void smp_send_reschedule(int cpu) 142 { 143 __smp_send_ipi(cpu, SMP_MSG_RESCHEDULE); 144 } 145 146 static void stop_this_cpu(void *unused) 147 { 148 cpu_clear(smp_processor_id(), cpu_online_map); 149 local_irq_disable(); 150 151 for (;;) 152 cpu_relax(); 153 } 154 155 void smp_send_stop(void) 156 { 157 smp_call_function(stop_this_cpu, 0, 1, 0); 158 } 159 160 161 struct smp_fn_call_struct smp_fn_call = { 162 .lock = SPIN_LOCK_UNLOCKED, 163 .finished = ATOMIC_INIT(0), 164 }; 165 166 /* 167 * The caller of this wants the passed function to run on every cpu. If wait 168 * is set, wait until all cpus have finished the function before returning. 169 * The lock is here to protect the call structure. 170 * You must not call this function with disabled interrupts or from a 171 * hardware interrupt handler or from a bottom half handler. 172 */ 173 int smp_call_function(void (*func)(void *info), void *info, int retry, int wait) 174 { 175 unsigned int nr_cpus = atomic_read(&cpus_booted); 176 int i; 177 178 if (nr_cpus < 2) 179 return 0; 180 181 /* Can deadlock when called with interrupts disabled */ 182 WARN_ON(irqs_disabled()); 183 184 spin_lock(&smp_fn_call.lock); 185 186 atomic_set(&smp_fn_call.finished, 0); 187 smp_fn_call.fn = func; 188 smp_fn_call.data = info; 189 190 for (i = 0; i < nr_cpus; i++) 191 if (i != smp_processor_id()) 192 __smp_call_function(i); 193 194 if (wait) 195 while (atomic_read(&smp_fn_call.finished) != (nr_cpus - 1)); 196 197 spin_unlock(&smp_fn_call.lock); 198 199 return 0; 200 } 201 202 /* Not really SMP stuff ... */ 203 int setup_profiling_timer(unsigned int multiplier) 204 { 205 return 0; 206 } 207 208