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