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