getuser.S 1.5 KB

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  1. /*
  2. * linux/arch/arm/lib/getuser.S
  3. *
  4. * Copyright (C) 2001 Russell King
  5. *
  6. * This program is free software; you can redistribute it and/or modify
  7. * it under the terms of the GNU General Public License version 2 as
  8. * published by the Free Software Foundation.
  9. *
  10. * Idea from x86 version, (C) Copyright 1998 Linus Torvalds
  11. *
  12. * These functions have a non-standard call interface to make them more
  13. * efficient, especially as they return an error value in addition to
  14. * the "real" return value.
  15. *
  16. * __get_user_X
  17. *
  18. * Inputs: r0 contains the address
  19. * Outputs: r0 is the error code
  20. * r2, r3 contains the zero-extended value
  21. * lr corrupted
  22. *
  23. * No other registers must be altered. (see include/asm-arm/uaccess.h
  24. * for specific ASM register usage).
  25. *
  26. * Note that ADDR_LIMIT is either 0 or 0xc0000000.
  27. * Note also that it is intended that __get_user_bad is not global.
  28. */
  29. #include <asm/asm-offsets.h>
  30. #include <asm/thread_info.h>
  31. #include <asm/errno.h>
  32. .global __get_user_1
  33. __get_user_1:
  34. 1: ldrbt r2, [r0]
  35. mov r0, #0
  36. mov pc, lr
  37. .global __get_user_2
  38. __get_user_2:
  39. 2: ldrbt r2, [r0], #1
  40. 3: ldrbt r3, [r0]
  41. #ifndef __ARMEB__
  42. orr r2, r2, r3, lsl #8
  43. #else
  44. orr r2, r3, r2, lsl #8
  45. #endif
  46. mov r0, #0
  47. mov pc, lr
  48. .global __get_user_4
  49. __get_user_4:
  50. 4: ldrt r2, [r0]
  51. mov r0, #0
  52. mov pc, lr
  53. __get_user_bad:
  54. mov r2, #0
  55. mov r0, #-EFAULT
  56. mov pc, lr
  57. .section __ex_table, "a"
  58. .long 1b, __get_user_bad
  59. .long 2b, __get_user_bad
  60. .long 3b, __get_user_bad
  61. .long 4b, __get_user_bad
  62. .previous