vfork.S 1.8 KB

12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970
  1. /* Copyright (C) 2004 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. The GNU C Library is free software; you can redistribute it and/or
  4. modify it under the terms of the GNU Lesser General Public
  5. License as published by the Free Software Foundation; either
  6. version 2.1 of the License, or (at your option) any later version.
  7. The GNU C Library is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10. Lesser General Public License for more details.
  11. You should have received a copy of the GNU Lesser General Public
  12. License along with the GNU C Library; if not, see
  13. <http://www.gnu.org/licenses/>. */
  14. #include <sysdep.h>
  15. #define _ERRNO_H 1
  16. #include <bits/errno.h>
  17. #include <tcb-offsets.h>
  18. /* Clone the calling process, but without copying the whole address space.
  19. The calling process is suspended until the new process exits or is
  20. replaced by a call to `execve'. Return -1 for errors, 0 to the new process,
  21. and the process ID of the new process to the old process. */
  22. ENTRY (__vfork)
  23. /* Save the PID value. */
  24. stc gbr, r2
  25. mov.w .L2, r0
  26. mov.l @(r0,r2), r4
  27. neg r4, r1
  28. tst r1, r1
  29. bf 1f
  30. mov #1, r1
  31. rotr r1
  32. 1:
  33. mov.l r1, @(r0,r2)
  34. mov.w .L1, r3
  35. trapa #0x10
  36. mov r0, r1
  37. /* Restore the old PID value in the parent. */
  38. tst r0, r0
  39. bt.s 2f
  40. stc gbr, r2
  41. mov.w .L2, r0
  42. mov.l r4, @(r0,r2)
  43. mov r1, r0
  44. 2:
  45. mov #-12, r2
  46. shad r2, r1
  47. not r1, r1 // r1=0 means r0 = -1 to -4095
  48. tst r1, r1 // i.e. error in linux
  49. bf .Lpseudo_end
  50. SYSCALL_ERROR_HANDLER
  51. .Lpseudo_end:
  52. rts
  53. nop
  54. .L1:
  55. .word __NR_vfork
  56. .L2:
  57. .word PID - TLS_PRE_TCB_SIZE
  58. .align 2
  59. PSEUDO_END (__vfork)
  60. hidden_def (vfork)
  61. weak_alias (__vfork, vfork)