tls.h 6.2 KB

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  1. /* Definition for thread-local data handling. linuxthreads/i386 version.
  2. Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
  3. This file is part of the GNU C Library.
  4. The GNU C Library is free software; you can redistribute it and/or
  5. modify it under the terms of the GNU Lesser General Public
  6. License as published by the Free Software Foundation; either
  7. version 2.1 of the License, or (at your option) any later version.
  8. The GNU C Library is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11. Lesser General Public License for more details.
  12. You should have received a copy of the GNU Lesser General Public
  13. License along with the GNU C Library; if not, write to the Free
  14. Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  15. 02111-1307 USA. */
  16. #ifndef _TLS_H
  17. #define _TLS_H
  18. # include <pt-machine.h>
  19. #ifndef __ASSEMBLER__
  20. # include <stdbool.h>
  21. # include <stddef.h>
  22. # include <stdint.h>
  23. /* Type for the dtv. */
  24. typedef union dtv
  25. {
  26. size_t counter;
  27. void *pointer;
  28. } dtv_t;
  29. typedef struct
  30. {
  31. void *tcb; /* Pointer to the TCB. Not necessary the
  32. thread descriptor used by libpthread. */
  33. dtv_t *dtv;
  34. void *self; /* Pointer to the thread descriptor. */
  35. } tcbhead_t;
  36. #endif
  37. /* We can support TLS only if the floating-stack support is available. */
  38. #if defined FLOATING_STACKS && defined HAVE_TLS_SUPPORT
  39. /* Signal that TLS support is available. */
  40. //# define USE_TLS 1
  41. # ifndef __ASSEMBLER__
  42. /* Get system call information. */
  43. # include <sysdep.h>
  44. /* Get the thread descriptor definition. */
  45. # include <linuxthreads/descr.h>
  46. /* This is the size of the initial TCB. */
  47. # define TLS_INIT_TCB_SIZE sizeof (tcbhead_t)
  48. /* Alignment requirements for the initial TCB. */
  49. # define TLS_INIT_TCB_ALIGN __alignof__ (tcbhead_t)
  50. /* This is the size of the TCB. */
  51. # define TLS_TCB_SIZE sizeof (struct _pthread_descr_struct)
  52. /* Alignment requirements for the TCB. */
  53. # define TLS_TCB_ALIGN __alignof__ (struct _pthread_descr_struct)
  54. /* The TCB can have any size and the memory following the address the
  55. thread pointer points to is unspecified. Allocate the TCB there. */
  56. # define TLS_TCB_AT_TP 1
  57. /* Install the dtv pointer. The pointer passed is to the element with
  58. index -1 which contain the length. */
  59. # define INSTALL_DTV(descr, dtvp) \
  60. ((tcbhead_t *) (descr))->dtv = (dtvp) + 1
  61. /* Install new dtv for current thread. */
  62. # define INSTALL_NEW_DTV(dtv) \
  63. ({ struct _pthread_descr_struct *__descr; \
  64. THREAD_SETMEM (__descr, p_header.data.dtvp, (dtv)); })
  65. /* Return dtv of given thread descriptor. */
  66. # define GET_DTV(descr) \
  67. (((tcbhead_t *) (descr))->dtv)
  68. # ifdef __PIC__
  69. # define TLS_EBX_ARG "r"
  70. # define TLS_LOAD_EBX "xchgl %3, %%ebx\n\t"
  71. # else
  72. # define TLS_EBX_ARG "b"
  73. # define TLS_LOAD_EBX
  74. # endif
  75. # define TLS_DO_MODIFY_LDT(descr, nr) \
  76. ({ \
  77. struct modify_ldt_ldt_s ldt_entry = \
  78. { nr, (unsigned long int) (descr), 0xfffff /* 4GB in pages */, \
  79. 1, 0, 0, 1, 0, 1, 0 }; \
  80. int result; \
  81. __asm__ __volatile__ (TLS_LOAD_EBX \
  82. "int $0x80\n\t" \
  83. TLS_LOAD_EBX \
  84. : "=a" (result) \
  85. : "0" (__NR_modify_ldt), \
  86. /* The extra argument with the "m" constraint is necessary \
  87. to let the compiler know that we are accessing LDT_ENTRY \
  88. here. */ \
  89. "m" (ldt_entry), TLS_EBX_ARG (1), "c" (&ldt_entry), \
  90. "d" (sizeof (ldt_entry))); \
  91. __builtin_expect (result, 0) != 0 ? -1 : nr * 8 + 7; \
  92. })
  93. # define TLS_DO_SET_THREAD_AREA(descr, secondcall) \
  94. ({ \
  95. struct modify_ldt_ldt_s ldt_entry = \
  96. { -1, (unsigned long int) (descr), 0xfffff /* 4GB in pages */, \
  97. 1, 0, 0, 1, 0, 1, 0 }; \
  98. int result; \
  99. if (secondcall) \
  100. ldt_entry.entry_number = ({ int _gs; \
  101. __asm__ ("movw %%gs, %w0" : "=q" (_gs)); \
  102. (_gs & 0xffff) >> 3; }); \
  103. __asm__ __volatile__ (TLS_LOAD_EBX \
  104. "int $0x80\n\t" \
  105. TLS_LOAD_EBX \
  106. : "=a" (result), "=m" (ldt_entry.entry_number) \
  107. : "0" (__NR_set_thread_area), \
  108. /* The extra argument with the "m" constraint is necessary \
  109. to let the compiler know that we are accessing LDT_ENTRY \
  110. here. */ \
  111. TLS_EBX_ARG (&ldt_entry), "m" (ldt_entry)); \
  112. __builtin_expect (result, 0) == 0 ? ldt_entry.entry_number * 8 + 3 : -1; \
  113. })
  114. # ifdef __ASSUME_SET_THREAD_AREA_SYSCALL
  115. # define TLS_SETUP_GS_SEGMENT(descr, secondcall) \
  116. TLS_DO_SET_THREAD_AREA (descr, firstcall)
  117. # elif defined __NR_set_thread_area
  118. # define TLS_SETUP_GS_SEGMENT(descr, secondcall) \
  119. ({ int __seg = TLS_DO_SET_THREAD_AREA (descr, secondcall); \
  120. __seg == -1 ? TLS_DO_MODIFY_LDT (descr, 0) : __seg; })
  121. # else
  122. # define TLS_SETUP_GS_SEGMENT(descr, secondcall) \
  123. TLS_DO_MODIFY_LDT ((descr), 0)
  124. # endif
  125. /* Code to initially initialize the thread pointer. This might need
  126. special attention since 'errno' is not yet available and if the
  127. operation can cause a failure 'errno' must not be touched. */
  128. # define TLS_INIT_TP(descr, secondcall) \
  129. ({ \
  130. void *_descr = (descr); \
  131. tcbhead_t *head = _descr; \
  132. int __gs; \
  133. \
  134. head->tcb = _descr; \
  135. /* For now the thread descriptor is at the same address. */ \
  136. head->self = _descr; \
  137. \
  138. __gs = TLS_SETUP_GS_SEGMENT (_descr, secondcall); \
  139. if (__builtin_expect (__gs, 7) != -1) \
  140. { \
  141. __asm__ ("movw %w0, %%gs" : : "q" (__gs)); \
  142. __gs = 0; \
  143. } \
  144. __gs; \
  145. })
  146. /* Return the address of the dtv for the current thread. */
  147. # define THREAD_DTV() \
  148. ({ struct _pthread_descr_struct *__descr; \
  149. THREAD_GETMEM (__descr, p_header.data.dtvp); })
  150. # endif /* FLOATING_STACKS && HAVE_TLS_SUPPORT */
  151. #endif /* __ASSEMBLER__ */
  152. #endif /* tls.h */