copy_from_user.S 1.4 KB

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  1. /* SPDX-License-Identifier: GPL-2.0-only */
  2. /*
  3. * Copyright (C) 2012 ARM Ltd.
  4. */
  5. #include <linux/linkage.h>
  6. #include <asm/asm-uaccess.h>
  7. #include <asm/assembler.h>
  8. #include <asm/cache.h>
  9. /*
  10. * Copy from user space to a kernel buffer (alignment handled by the hardware)
  11. *
  12. * Parameters:
  13. * x0 - to
  14. * x1 - from
  15. * x2 - n
  16. * Returns:
  17. * x0 - bytes not copied
  18. */
  19. .macro ldrb1 reg, ptr, val
  20. uao_user_alternative 9998f, ldrb, ldtrb, \reg, \ptr, \val
  21. .endm
  22. .macro strb1 reg, ptr, val
  23. strb \reg, [\ptr], \val
  24. .endm
  25. .macro ldrh1 reg, ptr, val
  26. uao_user_alternative 9997f, ldrh, ldtrh, \reg, \ptr, \val
  27. .endm
  28. .macro strh1 reg, ptr, val
  29. strh \reg, [\ptr], \val
  30. .endm
  31. .macro ldr1 reg, ptr, val
  32. uao_user_alternative 9997f, ldr, ldtr, \reg, \ptr, \val
  33. .endm
  34. .macro str1 reg, ptr, val
  35. str \reg, [\ptr], \val
  36. .endm
  37. .macro ldp1 reg1, reg2, ptr, val
  38. uao_ldp 9997f, \reg1, \reg2, \ptr, \val
  39. .endm
  40. .macro stp1 reg1, reg2, ptr, val
  41. stp \reg1, \reg2, [\ptr], \val
  42. .endm
  43. end .req x5
  44. srcin .req x15
  45. SYM_FUNC_START(__arch_copy_from_user)
  46. add end, x0, x2
  47. mov srcin, x1
  48. #include "copy_template.S"
  49. mov x0, #0 // Nothing to copy
  50. ret
  51. SYM_FUNC_END(__arch_copy_from_user)
  52. EXPORT_SYMBOL(__arch_copy_from_user)
  53. .section .fixup,"ax"
  54. .align 2
  55. 9997: cmp dst, dstin
  56. b.ne 9998f
  57. // Before being absolutely sure we couldn't copy anything, try harder
  58. USER(9998f, ldtrb tmp1w, [srcin])
  59. strb tmp1w, [dst], #1
  60. 9998: sub x0, end, dst // bytes not copied
  61. ret
  62. .previous