/arch/ppc64/kernel/vdso64/datapage.S

https://bitbucket.org/evzijst/gittest · Assembly · 68 lines · 40 code · 6 blank · 22 comment · 0 complexity · d2b4b6e829e19492110eca946edb64e4 MD5 · raw file 

    

  1. /*
    2. 

  2.  * Access to the shared data page by the vDSO & syscall map
    3. 

  3.  *
    4. 

  4.  * Copyright (C) 2004 Benjamin Herrenschmuidt (benh@kernel.crashing.org), IBM Corp.
    5. 

  5.  *
    6. 

  6.  * This program is free software; you can redistribute it and/or
    7. 

  7.  * modify it under the terms of the GNU General Public License
    8. 

  8.  * as published by the Free Software Foundation; either version
    9. 

  9.  * 2 of the License, or (at your option) any later version.
    10. 

  10.  */
    11. 

  11. 

  12. #include <linux/config.h>
    13. 

  13. #include <asm/processor.h>
    14. 

  14. #include <asm/ppc_asm.h>
    15. 

  15. #include <asm/offsets.h>
    16. 

  16. #include <asm/unistd.h>
    17. 

  17. #include <asm/vdso.h>
    18. 

  18. 

  19. 	.text
    20. 

  20. V_FUNCTION_BEGIN(__get_datapage)
    21. 

  21.   .cfi_startproc
    22. 

  22. 	/* We don't want that exposed or overridable as we want other objects
    23. 

  23. 	 * to be able to bl directly to here
    24. 

  24. 	 */
    25. 

  25. 	.protected __get_datapage
    26. 

  26. 	.hidden __get_datapage
    27. 

  27. 

  28. 	mflr	r0
    29. 

  29.   .cfi_register lr,r0
    30. 

  30. 

  31. 	bcl	20,31,1f
    32. 

  32. 	.global	__kernel_datapage_offset;
    33. 

  33. __kernel_datapage_offset:
    34. 

  34. 	.long	0
    35. 

  35. 1:
    36. 

  36. 	mflr	r3
    37. 

  37. 	mtlr	r0
    38. 

  38. 	lwz	r0,0(r3)
    39. 

  39. 	add	r3,r0,r3
    40. 

  40. 	blr
    41. 

  41.   .cfi_endproc
    42. 

  42. V_FUNCTION_END(__get_datapage)
    43. 

  43. 

  44. /*
    45. 

  45.  * void *__kernel_get_syscall_map(unsigned int *syscall_count) ;
    46. 

  46.  *
    47. 

  47.  * returns a pointer to the syscall map. the map is agnostic to the
    48. 

  48.  * size of "long", unlike kernel bitops, it stores bits from top to
    49. 

  49.  * bottom so that memory actually contains a linear bitmap
    50. 

  50.  * check for syscall N by testing bit (0x80000000 >> (N & 0x1f)) of
    51. 

  51.  * 32 bits int at N >> 5.
    52. 

  52.  */
    53. 

  53. V_FUNCTION_BEGIN(__kernel_get_syscall_map)
    54. 

  54.   .cfi_startproc
    55. 

  55. 	mflr	r12
    56. 

  56.   .cfi_register lr,r12
    57. 

  57. 

  58. 	mr	r4,r3
    59. 

  59. 	bl	V_LOCAL_FUNC(__get_datapage)
    60. 

  60. 	mtlr	r12
    61. 

  61. 	addi	r3,r3,CFG_SYSCALL_MAP64
    62. 

  62. 	cmpli	cr0,r4,0
    63. 

  63. 	beqlr
    64. 

  64. 	li	r0,__NR_syscalls
    65. 

  65. 	stw	r0,0(r4)
    66. 

  66. 	blr
    67. 

  67.   .cfi_endproc
    68. 

  68. V_FUNCTION_END(__kernel_get_syscall_map)
    69.