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 set_cpu_online(cpu, true); 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 set_cpu_online(me, true); 114 cpu_set(me, cpu_callin_map); 115 116 err = os_pipe(cpu_data[me].ipi_pipe, 1, 1); 117 if (err < 0) 118 panic("CPU#0 failed to create IPI pipe, errno = %d", -err); 119 120 os_set_fd_async(cpu_data[me].ipi_pipe[0]); 121 122 for (cpu = 1; cpu < ncpus; cpu++) { 123 printk(KERN_INFO "Booting processor %d...\n", cpu); 124 125 idle = idle_thread(cpu); 126 127 init_idle(idle, cpu); 128 129 waittime = 200000000; 130 while (waittime-- && !cpu_isset(cpu, cpu_callin_map)) 131 cpu_relax(); 132 133 printk(KERN_INFO "%s\n", 134 cpu_isset(cpu, cpu_calling_map) ? "done" : "failed"); 135 } 136 } 137 138 void smp_prepare_boot_cpu(void) 139 { 140 set_cpu_online(smp_processor_id(), true); 141 } 142 143 int __cpu_up(unsigned int cpu, struct task_struct *tidle) 144 { 145 cpu_set(cpu, smp_commenced_mask); 146 while (!cpu_online(cpu)) 147 mb(); 148 return 0; 149 } 150 151 int setup_profiling_timer(unsigned int multiplier) 152 { 153 printk(KERN_INFO "setup_profiling_timer\n"); 154 return 0; 155 } 156 157 void smp_call_function_slave(int cpu); 158 159 void IPI_handler(int cpu) 160 { 161 unsigned char c; 162 int fd; 163 164 fd = cpu_data[cpu].ipi_pipe[0]; 165 while (os_read_file(fd, &c, 1) == 1) { 166 switch (c) { 167 case 'C': 168 smp_call_function_slave(cpu); 169 break; 170 171 case 'R': 172 scheduler_ipi(); 173 break; 174 175 case 'S': 176 printk(KERN_INFO "CPU#%d stopping\n", cpu); 177 while (1) 178 pause(); 179 break; 180 181 default: 182 printk(KERN_ERR "CPU#%d received unknown IPI [%c]!\n", 183 cpu, c); 184 break; 185 } 186 } 187 } 188 189 int hard_smp_processor_id(void) 190 { 191 return pid_to_processor_id(os_getpid()); 192 } 193 194 static DEFINE_SPINLOCK(call_lock); 195 static atomic_t scf_started; 196 static atomic_t scf_finished; 197 static void (*func)(void *info); 198 static void *info; 199 200 void smp_call_function_slave(int cpu) 201 { 202 atomic_inc(&scf_started); 203 (*func)(info); 204 atomic_inc(&scf_finished); 205 } 206 207 int smp_call_function(void (*_func)(void *info), void *_info, int wait) 208 { 209 int cpus = num_online_cpus() - 1; 210 int i; 211 212 if (!cpus) 213 return 0; 214 215 /* Can deadlock when called with interrupts disabled */ 216 WARN_ON(irqs_disabled()); 217 218 spin_lock_bh(&call_lock); 219 atomic_set(&scf_started, 0); 220 atomic_set(&scf_finished, 0); 221 func = _func; 222 info = _info; 223 224 for_each_online_cpu(i) 225 os_write_file(cpu_data[i].ipi_pipe[1], "C", 1); 226 227 while (atomic_read(&scf_started) != cpus) 228 barrier(); 229 230 if (wait) 231 while (atomic_read(&scf_finished) != cpus) 232 barrier(); 233 234 spin_unlock_bh(&call_lock); 235 return 0; 236 } 237 238 #endif 239