process.c 3.6 KB

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  1. /*
  2. * linux/arch/cris/kernel/process.c
  3. *
  4. * Copyright (C) 1995 Linus Torvalds
  5. * Copyright (C) 2000-2002 Axis Communications AB
  6. *
  7. * Authors: Bjorn Wesen (bjornw@axis.com)
  8. *
  9. */
  10. /*
  11. * This file handles the architecture-dependent parts of process handling..
  12. */
  13. #include <linux/atomic.h>
  14. #include <asm/pgtable.h>
  15. #include <asm/uaccess.h>
  16. #include <asm/irq.h>
  17. #include <linux/module.h>
  18. #include <linux/spinlock.h>
  19. #include <linux/init_task.h>
  20. #include <linux/sched.h>
  21. #include <linux/fs.h>
  22. #include <linux/user.h>
  23. #include <linux/elfcore.h>
  24. #include <linux/mqueue.h>
  25. #include <linux/reboot.h>
  26. #include <linux/rcupdate.h>
  27. //#define DEBUG
  28. /*
  29. * Initial task structure. Make this a per-architecture thing,
  30. * because different architectures tend to have different
  31. * alignment requirements and potentially different initial
  32. * setup.
  33. */
  34. static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
  35. static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
  36. /*
  37. * Initial thread structure.
  38. *
  39. * We need to make sure that this is 8192-byte aligned due to the
  40. * way process stacks are handled. This is done by having a special
  41. * "init_task" linker map entry..
  42. */
  43. union thread_union init_thread_union __init_task_data =
  44. { INIT_THREAD_INFO(init_task) };
  45. /*
  46. * Initial task structure.
  47. *
  48. * All other task structs will be allocated on slabs in fork.c
  49. */
  50. struct task_struct init_task = INIT_TASK(init_task);
  51. EXPORT_SYMBOL(init_task);
  52. /*
  53. * The hlt_counter, disable_hlt and enable_hlt is just here as a hook if
  54. * there would ever be a halt sequence (for power save when idle) with
  55. * some largish delay when halting or resuming *and* a driver that can't
  56. * afford that delay. The hlt_counter would then be checked before
  57. * executing the halt sequence, and the driver marks the unhaltable
  58. * region by enable_hlt/disable_hlt.
  59. */
  60. int cris_hlt_counter=0;
  61. void disable_hlt(void)
  62. {
  63. cris_hlt_counter++;
  64. }
  65. EXPORT_SYMBOL(disable_hlt);
  66. void enable_hlt(void)
  67. {
  68. cris_hlt_counter--;
  69. }
  70. EXPORT_SYMBOL(enable_hlt);
  71. /*
  72. * The following aren't currently used.
  73. */
  74. void (*pm_idle)(void);
  75. extern void default_idle(void);
  76. void (*pm_power_off)(void);
  77. EXPORT_SYMBOL(pm_power_off);
  78. /*
  79. * The idle thread. There's no useful work to be
  80. * done, so just try to conserve power and have a
  81. * low exit latency (ie sit in a loop waiting for
  82. * somebody to say that they'd like to reschedule)
  83. */
  84. void cpu_idle (void)
  85. {
  86. /* endless idle loop with no priority at all */
  87. while (1) {
  88. rcu_idle_enter();
  89. while (!need_resched()) {
  90. void (*idle)(void);
  91. /*
  92. * Mark this as an RCU critical section so that
  93. * synchronize_kernel() in the unload path waits
  94. * for our completion.
  95. */
  96. idle = pm_idle;
  97. if (!idle)
  98. idle = default_idle;
  99. idle();
  100. }
  101. rcu_idle_exit();
  102. schedule_preempt_disabled();
  103. }
  104. }
  105. void hard_reset_now (void);
  106. void machine_restart(char *cmd)
  107. {
  108. hard_reset_now();
  109. }
  110. /*
  111. * Similar to machine_power_off, but don't shut off power. Add code
  112. * here to freeze the system for e.g. post-mortem debug purpose when
  113. * possible. This halt has nothing to do with the idle halt.
  114. */
  115. void machine_halt(void)
  116. {
  117. }
  118. /* If or when software power-off is implemented, add code here. */
  119. void machine_power_off(void)
  120. {
  121. }
  122. /*
  123. * When a process does an "exec", machine state like FPU and debug
  124. * registers need to be reset. This is a hook function for that.
  125. * Currently we don't have any such state to reset, so this is empty.
  126. */
  127. void flush_thread(void)
  128. {
  129. }
  130. /* Fill in the fpu structure for a core dump. */
  131. int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
  132. {
  133. return 0;
  134. }