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 } 204 205