process.c 2.7 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130
  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. //#define DEBUG
  27. /*
  28. * The hlt_counter, disable_hlt and enable_hlt is just here as a hook if
  29. * there would ever be a halt sequence (for power save when idle) with
  30. * some largish delay when halting or resuming *and* a driver that can't
  31. * afford that delay. The hlt_counter would then be checked before
  32. * executing the halt sequence, and the driver marks the unhaltable
  33. * region by enable_hlt/disable_hlt.
  34. */
  35. int cris_hlt_counter=0;
  36. void disable_hlt(void)
  37. {
  38. cris_hlt_counter++;
  39. }
  40. EXPORT_SYMBOL(disable_hlt);
  41. void enable_hlt(void)
  42. {
  43. cris_hlt_counter--;
  44. }
  45. EXPORT_SYMBOL(enable_hlt);
  46. /*
  47. * The following aren't currently used.
  48. */
  49. void (*pm_idle)(void);
  50. extern void default_idle(void);
  51. void (*pm_power_off)(void);
  52. EXPORT_SYMBOL(pm_power_off);
  53. /*
  54. * The idle thread. There's no useful work to be
  55. * done, so just try to conserve power and have a
  56. * low exit latency (ie sit in a loop waiting for
  57. * somebody to say that they'd like to reschedule)
  58. */
  59. void cpu_idle (void)
  60. {
  61. /* endless idle loop with no priority at all */
  62. while (1) {
  63. while (!need_resched()) {
  64. void (*idle)(void);
  65. /*
  66. * Mark this as an RCU critical section so that
  67. * synchronize_kernel() in the unload path waits
  68. * for our completion.
  69. */
  70. idle = pm_idle;
  71. if (!idle)
  72. idle = default_idle;
  73. idle();
  74. }
  75. schedule_preempt_disabled();
  76. }
  77. }
  78. void hard_reset_now (void);
  79. void machine_restart(char *cmd)
  80. {
  81. hard_reset_now();
  82. }
  83. /*
  84. * Similar to machine_power_off, but don't shut off power. Add code
  85. * here to freeze the system for e.g. post-mortem debug purpose when
  86. * possible. This halt has nothing to do with the idle halt.
  87. */
  88. void machine_halt(void)
  89. {
  90. }
  91. /* If or when software power-off is implemented, add code here. */
  92. void machine_power_off(void)
  93. {
  94. }
  95. /*
  96. * When a process does an "exec", machine state like FPU and debug
  97. * registers need to be reset. This is a hook function for that.
  98. * Currently we don't have any such state to reset, so this is empty.
  99. */
  100. void flush_thread(void)
  101. {
  102. }
  103. /* Fill in the fpu structure for a core dump. */
  104. int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
  105. {
  106. return 0;
  107. }