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 notify_cpu_starting(cpu); 89 cpu_set(cpu, cpu_online_map); 90 default_idle(); 91 return 0; 92 } 93 94 static struct task_struct *idle_thread(int cpu) 95 { 96 struct task_struct *new_task; 97 98 current->thread.request.u.thread.proc = idle_proc; 99 current->thread.request.u.thread.arg = (void *) cpu; 100 new_task = fork_idle(cpu); 101 if (IS_ERR(new_task)) 102 panic("copy_process failed in idle_thread, error = %ld", 103 PTR_ERR(new_task)); 104 105 cpu_tasks[cpu] = ((struct cpu_task) 106 { .pid = new_task->thread.mode.tt.extern_pid, 107 .task = new_task } ); 108 idle_threads[cpu] = new_task; 109 panic("skas mode doesn't support SMP"); 110 return new_task; 111 } 112 113 void smp_prepare_cpus(unsigned int maxcpus) 114 { 115 struct task_struct *idle; 116 unsigned long waittime; 117 int err, cpu, me = smp_processor_id(); 118 int i; 119 120 for (i = 0; i < ncpus; ++i) 121 cpu_set(i, cpu_possible_map); 122 123 cpu_clear(me, cpu_online_map); 124 cpu_set(me, cpu_online_map); 125 cpu_set(me, cpu_callin_map); 126 127 err = os_pipe(cpu_data[me].ipi_pipe, 1, 1); 128 if (err < 0) 129 panic("CPU#0 failed to create IPI pipe, errno = %d", -err); 130 131 os_set_fd_async(cpu_data[me].ipi_pipe[0]); 132 133 for (cpu = 1; cpu < ncpus; cpu++) { 134 printk(KERN_INFO "Booting processor %d...\n", cpu); 135 136 idle = idle_thread(cpu); 137 138 init_idle(idle, cpu); 139 140 waittime = 200000000; 141 while (waittime-- && !cpu_isset(cpu, cpu_callin_map)) 142 cpu_relax(); 143 144 printk(KERN_INFO "%s\n", 145 cpu_isset(cpu, cpu_calling_map) ? "done" : "failed"); 146 } 147 } 148 149 void smp_prepare_boot_cpu(void) 150 { 151 cpu_set(smp_processor_id(), cpu_online_map); 152 } 153 154 int __cpu_up(unsigned int cpu) 155 { 156 cpu_set(cpu, smp_commenced_mask); 157 while (!cpu_isset(cpu, cpu_online_map)) 158 mb(); 159 return 0; 160 } 161 162 int setup_profiling_timer(unsigned int multiplier) 163 { 164 printk(KERN_INFO "setup_profiling_timer\n"); 165 return 0; 166 } 167 168 void smp_call_function_slave(int cpu); 169 170 void IPI_handler(int cpu) 171 { 172 unsigned char c; 173 int fd; 174 175 fd = cpu_data[cpu].ipi_pipe[0]; 176 while (os_read_file(fd, &c, 1) == 1) { 177 switch (c) { 178 case 'C': 179 smp_call_function_slave(cpu); 180 break; 181 182 case 'R': 183 set_tsk_need_resched(current); 184 break; 185 186 case 'S': 187 printk(KERN_INFO "CPU#%d stopping\n", cpu); 188 while (1) 189 pause(); 190 break; 191 192 default: 193 printk(KERN_ERR "CPU#%d received unknown IPI [%c]!\n", 194 cpu, c); 195 break; 196 } 197 } 198 } 199 200 int hard_smp_processor_id(void) 201 { 202 return pid_to_processor_id(os_getpid()); 203 } 204 205 static DEFINE_SPINLOCK(call_lock); 206 static atomic_t scf_started; 207 static atomic_t scf_finished; 208 static void (*func)(void *info); 209 static void *info; 210 211 void smp_call_function_slave(int cpu) 212 { 213 atomic_inc(&scf_started); 214 (*func)(info); 215 atomic_inc(&scf_finished); 216 } 217 218 int smp_call_function(void (*_func)(void *info), void *_info, int wait) 219 { 220 int cpus = num_online_cpus() - 1; 221 int i; 222 223 if (!cpus) 224 return 0; 225 226 /* Can deadlock when called with interrupts disabled */ 227 WARN_ON(irqs_disabled()); 228 229 spin_lock_bh(&call_lock); 230 atomic_set(&scf_started, 0); 231 atomic_set(&scf_finished, 0); 232 func = _func; 233 info = _info; 234 235 for_each_online_cpu(i) 236 os_write_file(cpu_data[i].ipi_pipe[1], "C", 1); 237 238 while (atomic_read(&scf_started) != cpus) 239 barrier(); 240 241 if (wait) 242 while (atomic_read(&scf_finished) != cpus) 243 barrier(); 244 245 spin_unlock_bh(&call_lock); 246 return 0; 247 } 248 249 #endif 250