smp.c 5.7 KB

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  1. /*
  2. * Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
  3. * Licensed under the GPL
  4. */
  5. #include "linux/percpu.h"
  6. #include "asm/pgalloc.h"
  7. #include "asm/tlb.h"
  8. /* For some reason, mmu_gathers are referenced when CONFIG_SMP is off. */
  9. DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  10. #ifdef CONFIG_SMP
  11. #include "linux/sched.h"
  12. #include "linux/module.h"
  13. #include "linux/threads.h"
  14. #include "linux/interrupt.h"
  15. #include "linux/err.h"
  16. #include "linux/hardirq.h"
  17. #include "asm/smp.h"
  18. #include "asm/processor.h"
  19. #include "asm/spinlock.h"
  20. #include "user_util.h"
  21. #include "kern_util.h"
  22. #include "kern.h"
  23. #include "irq_user.h"
  24. #include "os.h"
  25. /* CPU online map, set by smp_boot_cpus */
  26. cpumask_t cpu_online_map = CPU_MASK_NONE;
  27. cpumask_t cpu_possible_map = CPU_MASK_NONE;
  28. EXPORT_SYMBOL(cpu_online_map);
  29. EXPORT_SYMBOL(cpu_possible_map);
  30. /* Per CPU bogomips and other parameters
  31. * The only piece used here is the ipi pipe, which is set before SMP is
  32. * started and never changed.
  33. */
  34. struct cpuinfo_um cpu_data[NR_CPUS];
  35. /* A statistic, can be a little off */
  36. int num_reschedules_sent = 0;
  37. /* Not changed after boot */
  38. struct task_struct *idle_threads[NR_CPUS];
  39. void smp_send_reschedule(int cpu)
  40. {
  41. os_write_file(cpu_data[cpu].ipi_pipe[1], "R", 1);
  42. num_reschedules_sent++;
  43. }
  44. void smp_send_stop(void)
  45. {
  46. int i;
  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("done\n");
  54. }
  55. static cpumask_t smp_commenced_mask = CPU_MASK_NONE;
  56. static cpumask_t cpu_callin_map = CPU_MASK_NONE;
  57. static int idle_proc(void *cpup)
  58. {
  59. int cpu = (int) cpup, err;
  60. err = os_pipe(cpu_data[cpu].ipi_pipe, 1, 1);
  61. if(err < 0)
  62. panic("CPU#%d failed to create IPI pipe, err = %d", cpu, -err);
  63. os_set_fd_async(cpu_data[cpu].ipi_pipe[0],
  64. current->thread.mode.tt.extern_pid);
  65. wmb();
  66. if (cpu_test_and_set(cpu, cpu_callin_map)) {
  67. printk("huh, CPU#%d already present??\n", cpu);
  68. BUG();
  69. }
  70. while (!cpu_isset(cpu, smp_commenced_mask))
  71. cpu_relax();
  72. cpu_set(cpu, cpu_online_map);
  73. default_idle();
  74. return(0);
  75. }
  76. static struct task_struct *idle_thread(int cpu)
  77. {
  78. struct task_struct *new_task;
  79. unsigned char c;
  80. current->thread.request.u.thread.proc = idle_proc;
  81. current->thread.request.u.thread.arg = (void *) cpu;
  82. new_task = fork_idle(cpu);
  83. if(IS_ERR(new_task))
  84. panic("copy_process failed in idle_thread, error = %ld",
  85. PTR_ERR(new_task));
  86. cpu_tasks[cpu] = ((struct cpu_task)
  87. { .pid = new_task->thread.mode.tt.extern_pid,
  88. .task = new_task } );
  89. idle_threads[cpu] = new_task;
  90. CHOOSE_MODE(os_write_file(new_task->thread.mode.tt.switch_pipe[1], &c,
  91. sizeof(c)),
  92. ({ panic("skas mode doesn't support SMP"); }));
  93. return(new_task);
  94. }
  95. void smp_prepare_cpus(unsigned int maxcpus)
  96. {
  97. struct task_struct *idle;
  98. unsigned long waittime;
  99. int err, cpu, me = smp_processor_id();
  100. int i;
  101. for (i = 0; i < ncpus; ++i)
  102. cpu_set(i, cpu_possible_map);
  103. cpu_clear(me, cpu_online_map);
  104. cpu_set(me, cpu_online_map);
  105. cpu_set(me, cpu_callin_map);
  106. err = os_pipe(cpu_data[me].ipi_pipe, 1, 1);
  107. if(err < 0)
  108. panic("CPU#0 failed to create IPI pipe, errno = %d", -err);
  109. os_set_fd_async(cpu_data[me].ipi_pipe[0],
  110. current->thread.mode.tt.extern_pid);
  111. for(cpu = 1; cpu < ncpus; cpu++){
  112. printk("Booting processor %d...\n", cpu);
  113. idle = idle_thread(cpu);
  114. init_idle(idle, cpu);
  115. waittime = 200000000;
  116. while (waittime-- && !cpu_isset(cpu, cpu_callin_map))
  117. cpu_relax();
  118. if (cpu_isset(cpu, cpu_callin_map))
  119. printk("done\n");
  120. else printk("failed\n");
  121. }
  122. }
  123. void smp_prepare_boot_cpu(void)
  124. {
  125. cpu_set(smp_processor_id(), cpu_online_map);
  126. }
  127. int __cpu_up(unsigned int cpu)
  128. {
  129. cpu_set(cpu, smp_commenced_mask);
  130. while (!cpu_isset(cpu, cpu_online_map))
  131. mb();
  132. return(0);
  133. }
  134. int setup_profiling_timer(unsigned int multiplier)
  135. {
  136. printk(KERN_INFO "setup_profiling_timer\n");
  137. return(0);
  138. }
  139. void smp_call_function_slave(int cpu);
  140. void IPI_handler(int cpu)
  141. {
  142. unsigned char c;
  143. int fd;
  144. fd = cpu_data[cpu].ipi_pipe[0];
  145. while (os_read_file(fd, &c, 1) == 1) {
  146. switch (c) {
  147. case 'C':
  148. smp_call_function_slave(cpu);
  149. break;
  150. case 'R':
  151. set_tsk_need_resched(current);
  152. break;
  153. case 'S':
  154. printk("CPU#%d stopping\n", cpu);
  155. while(1)
  156. pause();
  157. break;
  158. default:
  159. printk("CPU#%d received unknown IPI [%c]!\n", cpu, c);
  160. break;
  161. }
  162. }
  163. }
  164. int hard_smp_processor_id(void)
  165. {
  166. return(pid_to_processor_id(os_getpid()));
  167. }
  168. static DEFINE_SPINLOCK(call_lock);
  169. static atomic_t scf_started;
  170. static atomic_t scf_finished;
  171. static void (*func)(void *info);
  172. static void *info;
  173. void smp_call_function_slave(int cpu)
  174. {
  175. atomic_inc(&scf_started);
  176. (*func)(info);
  177. atomic_inc(&scf_finished);
  178. }
  179. int smp_call_function(void (*_func)(void *info), void *_info, int nonatomic,
  180. int wait)
  181. {
  182. int cpus = num_online_cpus() - 1;
  183. int i;
  184. if (!cpus)
  185. return 0;
  186. /* Can deadlock when called with interrupts disabled */
  187. WARN_ON(irqs_disabled());
  188. spin_lock_bh(&call_lock);
  189. atomic_set(&scf_started, 0);
  190. atomic_set(&scf_finished, 0);
  191. func = _func;
  192. info = _info;
  193. for_each_online_cpu(i)
  194. os_write_file(cpu_data[i].ipi_pipe[1], "C", 1);
  195. while (atomic_read(&scf_started) != cpus)
  196. barrier();
  197. if (wait)
  198. while (atomic_read(&scf_finished) != cpus)
  199. barrier();
  200. spin_unlock_bh(&call_lock);
  201. return 0;
  202. }
  203. #endif
  204. /*
  205. * Overrides for Emacs so that we follow Linus's tabbing style.
  206. * Emacs will notice this stuff at the end of the file and automatically
  207. * adjust the settings for this buffer only. This must remain at the end
  208. * of the file.
  209. * ---------------------------------------------------------------------------
  210. * Local variables:
  211. * c-file-style: "linux"
  212. * End:
  213. */