1 /* 2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 3 * Licensed under the GPL 4 */ 5 6 #include "linux/percpu.h" 7 #include "asm/pgalloc.h" 8 #include "asm/tlb.h" 9 10 /* For some reason, mmu_gathers are referenced when CONFIG_SMP is off. */ 11 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers); 12 13 #ifdef CONFIG_SMP 14 15 #include "linux/sched.h" 16 #include "linux/module.h" 17 #include "linux/threads.h" 18 #include "linux/interrupt.h" 19 #include "linux/err.h" 20 #include "linux/hardirq.h" 21 #include "asm/smp.h" 22 #include "asm/processor.h" 23 #include "asm/spinlock.h" 24 #include "kern.h" 25 #include "irq_user.h" 26 #include "os.h" 27 28 /* CPU online map, set by smp_boot_cpus */ 29 cpumask_t cpu_online_map = CPU_MASK_NONE; 30 cpumask_t cpu_possible_map = CPU_MASK_NONE; 31 32 EXPORT_SYMBOL(cpu_online_map); 33 EXPORT_SYMBOL(cpu_possible_map); 34 35 /* Per CPU bogomips and other parameters 36 * The only piece used here is the ipi pipe, which is set before SMP is 37 * started and never changed. 38 */ 39 struct cpuinfo_um cpu_data[NR_CPUS]; 40 41 /* A statistic, can be a little off */ 42 int num_reschedules_sent = 0; 43 44 /* Not changed after boot */ 45 struct task_struct *idle_threads[NR_CPUS]; 46 47 void smp_send_reschedule(int cpu) 48 { 49 os_write_file(cpu_data[cpu].ipi_pipe[1], "R", 1); 50 num_reschedules_sent++; 51 } 52 53 void smp_send_stop(void) 54 { 55 int i; 56 57 printk(KERN_INFO "Stopping all CPUs..."); 58 for (i = 0; i < num_online_cpus(); i++) { 59 if (i == current_thread->cpu) 60 continue; 61 os_write_file(cpu_data[i].ipi_pipe[1], "S", 1); 62 } 63 printk(KERN_CONT "done\n"); 64 } 65 66 static cpumask_t smp_commenced_mask = CPU_MASK_NONE; 67 static cpumask_t cpu_callin_map = CPU_MASK_NONE; 68 69 static int idle_proc(void *cpup) 70 { 71 int cpu = (int) cpup, err; 72 73 err = os_pipe(cpu_data[cpu].ipi_pipe, 1, 1); 74 if (err < 0) 75 panic("CPU#%d failed to create IPI pipe, err = %d", cpu, -err); 76 77 os_set_fd_async(cpu_data[cpu].ipi_pipe[0]); 78 79 wmb(); 80 if (cpu_test_and_set(cpu, cpu_callin_map)) { 81 printk(KERN_ERR "huh, CPU#%d already present??\n", cpu); 82 BUG(); 83 } 84 85 while (!cpu_isset(cpu, smp_commenced_mask)) 86 cpu_relax(); 87 88 cpu_set(cpu, cpu_online_map); 89 default_idle(); 90 return 0; 91 } 92 93 static struct task_struct *idle_thread(int cpu) 94 { 95 struct task_struct *new_task; 96 97 current->thread.request.u.thread.proc = idle_proc; 98 current->thread.request.u.thread.arg = (void *) cpu; 99 new_task = fork_idle(cpu); 100 if (IS_ERR(new_task)) 101 panic("copy_process failed in idle_thread, error = %ld", 102 PTR_ERR(new_task)); 103 104 cpu_tasks[cpu] = ((struct cpu_task) 105 { .pid = new_task->thread.mode.tt.extern_pid, 106 .task = new_task } ); 107 idle_threads[cpu] = new_task; 108 panic("skas mode doesn't support SMP"); 109 return new_task; 110 } 111 112 void smp_prepare_cpus(unsigned int maxcpus) 113 { 114 struct task_struct *idle; 115 unsigned long waittime; 116 int err, cpu, me = smp_processor_id(); 117 int i; 118 119 for (i = 0; i < ncpus; ++i) 120 cpu_set(i, cpu_possible_map); 121 122 cpu_clear(me, cpu_online_map); 123 cpu_set(me, cpu_online_map); 124 cpu_set(me, cpu_callin_map); 125 126 err = os_pipe(cpu_data[me].ipi_pipe, 1, 1); 127 if (err < 0) 128 panic("CPU#0 failed to create IPI pipe, errno = %d", -err); 129 130 os_set_fd_async(cpu_data[me].ipi_pipe[0]); 131 132 for (cpu = 1; cpu < ncpus; cpu++) { 133 printk(KERN_INFO "Booting processor %d...\n", cpu); 134 135 idle = idle_thread(cpu); 136 137 init_idle(idle, cpu); 138 139 waittime = 200000000; 140 while (waittime-- && !cpu_isset(cpu, cpu_callin_map)) 141 cpu_relax(); 142 143 printk(KERN_INFO "%s\n", 144 cpu_isset(cpu, cpu_calling_map) ? "done" : "failed"); 145 } 146 } 147 148 void smp_prepare_boot_cpu(void) 149 { 150 cpu_set(smp_processor_id(), cpu_online_map); 151 } 152 153 int __cpu_up(unsigned int cpu) 154 { 155 cpu_set(cpu, smp_commenced_mask); 156 while (!cpu_isset(cpu, cpu_online_map)) 157 mb(); 158 return 0; 159 } 160 161 int setup_profiling_timer(unsigned int multiplier) 162 { 163 printk(KERN_INFO "setup_profiling_timer\n"); 164 return 0; 165 } 166 167 void smp_call_function_slave(int cpu); 168 169 void IPI_handler(int cpu) 170 { 171 unsigned char c; 172 int fd; 173 174 fd = cpu_data[cpu].ipi_pipe[0]; 175 while (os_read_file(fd, &c, 1) == 1) { 176 switch (c) { 177 case 'C': 178 smp_call_function_slave(cpu); 179 break; 180 181 case 'R': 182 set_tsk_need_resched(current); 183 break; 184 185 case 'S': 186 printk(KERN_INFO "CPU#%d stopping\n", cpu); 187 while (1) 188 pause(); 189 break; 190 191 default: 192 printk(KERN_ERR "CPU#%d received unknown IPI [%c]!\n", 193 cpu, c); 194 break; 195 } 196 } 197 } 198 199 int hard_smp_processor_id(void) 200 { 201 return pid_to_processor_id(os_getpid()); 202 } 203 204 static DEFINE_SPINLOCK(call_lock); 205 static atomic_t scf_started; 206 static atomic_t scf_finished; 207 static void (*func)(void *info); 208 static void *info; 209 210 void smp_call_function_slave(int cpu) 211 { 212 atomic_inc(&scf_started); 213 (*func)(info); 214 atomic_inc(&scf_finished); 215 } 216 217 int smp_call_function(void (*_func)(void *info), void *_info, int wait) 218 { 219 int cpus = num_online_cpus() - 1; 220 int i; 221 222 if (!cpus) 223 return 0; 224 225 /* Can deadlock when called with interrupts disabled */ 226 WARN_ON(irqs_disabled()); 227 228 spin_lock_bh(&call_lock); 229 atomic_set(&scf_started, 0); 230 atomic_set(&scf_finished, 0); 231 func = _func; 232 info = _info; 233 234 for_each_online_cpu(i) 235 os_write_file(cpu_data[i].ipi_pipe[1], "C", 1); 236 237 while (atomic_read(&scf_started) != cpus) 238 barrier(); 239 240 if (wait) 241 while (atomic_read(&scf_finished) != cpus) 242 barrier(); 243 244 spin_unlock_bh(&call_lock); 245 return 0; 246 } 247 248 #endif 249