strncpy_from_user.S 952 B

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  1. /*
  2. * linux/arch/arm/lib/strncpy_from_user.S
  3. *
  4. * Copyright (C) 1995-2000 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. #include <linux/linkage.h>
  11. #include <asm/assembler.h>
  12. #include <asm/errno.h>
  13. .text
  14. .align 5
  15. /*
  16. * Copy a string from user space to kernel space.
  17. * r0 = dst, r1 = src, r2 = byte length
  18. * returns the number of characters copied (strlen of copied string),
  19. * -EFAULT on exception, or "len" if we fill the whole buffer
  20. */
  21. ENTRY(__strncpy_from_user)
  22. mov ip, r1
  23. 1: subs r2, r2, #1
  24. USER( ldrplbt r3, [r1], #1)
  25. bmi 2f
  26. strb r3, [r0], #1
  27. teq r3, #0
  28. bne 1b
  29. sub r1, r1, #1 @ take NUL character out of count
  30. 2: sub r0, r1, ip
  31. mov pc, lr
  32. .section .fixup,"ax"
  33. .align 0
  34. 9001: mov r3, #0
  35. strb r3, [r0, #0] @ null terminate
  36. mov r0, #-EFAULT
  37. mov pc, lr
  38. .previous