unwind-forcedunwind.c 5.1 KB

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  1. /* Copyright (C) 2003, 2005, 2007, 2009, 2010 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. Contributed by Jakub Jelinek <jakub@redhat.com>.
  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 License as
  6. published by the Free Software Foundation; either version 2.1 of the
  7. 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; see the file COPYING.LIB. If not,
  14. write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  15. Boston, MA 02111-1307, USA. */
  16. #include <dlfcn.h>
  17. #include <stdio.h>
  18. #include <unwind.h>
  19. #include <pthreadP.h>
  20. #define __libc_dlopen(x) dlopen(x, (RTLD_LOCAL | RTLD_LAZY))
  21. #define __libc_dlsym dlsym
  22. #define __libc_dlclose dlclose
  23. #define __libc_fatal(x) {/*write(STDERR_FILENO, x, strlen(x));*/ abort();}
  24. static void *libgcc_s_handle;
  25. static void (*libgcc_s_resume) (struct _Unwind_Exception *exc);
  26. static _Unwind_Reason_Code (*libgcc_s_personality)
  27. (_Unwind_State, struct _Unwind_Exception *, struct _Unwind_Context *);
  28. static _Unwind_Reason_Code (*libgcc_s_forcedunwind)
  29. (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
  30. static _Unwind_Word (*libgcc_s_getcfa) (struct _Unwind_Context *);
  31. void
  32. __attribute_noinline__
  33. pthread_cancel_init (void)
  34. {
  35. void *resume, *personality, *forcedunwind, *getcfa;
  36. void *handle;
  37. if (__builtin_expect (libgcc_s_handle != NULL, 1))
  38. {
  39. /* Force gcc to reload all values. */
  40. __asm__ __volatile__ ("" ::: "memory");
  41. return;
  42. }
  43. handle = __libc_dlopen ("libgcc_s.so.1");
  44. if (handle == NULL
  45. || (resume = __libc_dlsym (handle, "_Unwind_Resume")) == NULL
  46. || (personality = __libc_dlsym (handle, "__gcc_personality_v0")) == NULL
  47. || (forcedunwind = __libc_dlsym (handle, "_Unwind_ForcedUnwind"))
  48. == NULL
  49. || (getcfa = __libc_dlsym (handle, "_Unwind_GetCFA")) == NULL
  50. #ifdef ARCH_CANCEL_INIT
  51. || ARCH_CANCEL_INIT (handle)
  52. #endif
  53. )
  54. __libc_fatal ("libgcc_s.so.1 must be installed for pthread_cancel to work\n");
  55. libgcc_s_resume = resume;
  56. libgcc_s_personality = personality;
  57. libgcc_s_forcedunwind = forcedunwind;
  58. libgcc_s_getcfa = getcfa;
  59. /* Make sure libgcc_s_getcfa is written last. Otherwise,
  60. pthread_cancel_init might return early even when the pointer the
  61. caller is interested in is not initialized yet. */
  62. atomic_write_barrier ();
  63. libgcc_s_handle = handle;
  64. }
  65. void
  66. __libc_freeres_fn_section
  67. __unwind_freeres (void)
  68. {
  69. void *handle = libgcc_s_handle;
  70. if (handle != NULL)
  71. {
  72. libgcc_s_handle = NULL;
  73. __libc_dlclose (handle);
  74. }
  75. }
  76. #ifdef __thumb__
  77. void
  78. _Unwind_Resume (struct _Unwind_Exception *exc)
  79. {
  80. if (__builtin_expect (libgcc_s_resume == NULL, 0))
  81. pthread_cancel_init ();
  82. libgcc_s_resume (exc);
  83. }
  84. #else
  85. /* It's vitally important that _Unwind_Resume not have a stack frame; the
  86. ARM unwinder relies on register state at entrance. So we write this in
  87. assembly. */
  88. __asm__ (
  89. " .globl _Unwind_Resume\n"
  90. " .type _Unwind_Resume, %function\n"
  91. "_Unwind_Resume:\n"
  92. " .cfi_sections .debug_frame\n"
  93. " " CFI_STARTPROC "\n"
  94. " stmfd sp!, {r4, r5, r6, lr}\n"
  95. " " CFI_ADJUST_CFA_OFFSET (16)" \n"
  96. " " CFI_REL_OFFSET (r4, 0) "\n"
  97. " " CFI_REL_OFFSET (r5, 4) "\n"
  98. " " CFI_REL_OFFSET (r6, 8) "\n"
  99. " " CFI_REL_OFFSET (lr, 12) "\n"
  100. " " CFI_REMEMBER_STATE "\n"
  101. " ldr r4, 1f\n"
  102. " ldr r5, 2f\n"
  103. "3: add r4, pc, r4\n"
  104. " ldr r3, [r4, r5]\n"
  105. " mov r6, r0\n"
  106. " cmp r3, #0\n"
  107. " beq 4f\n"
  108. "5: mov r0, r6\n"
  109. " ldmfd sp!, {r4, r5, r6, lr}\n"
  110. " " CFI_ADJUST_CFA_OFFSET (-16) "\n"
  111. " " CFI_RESTORE (r4) "\n"
  112. " " CFI_RESTORE (r5) "\n"
  113. " " CFI_RESTORE (r6) "\n"
  114. " " CFI_RESTORE (lr) "\n"
  115. " bx r3\n"
  116. " " CFI_RESTORE_STATE "\n"
  117. "4: bl pthread_cancel_init\n"
  118. " ldr r3, [r4, r5]\n"
  119. " b 5b\n"
  120. " " CFI_ENDPROC "\n"
  121. " .align 2\n"
  122. #ifdef __thumb2__
  123. "1: .word _GLOBAL_OFFSET_TABLE_ - 3b - 4\n"
  124. #else
  125. "1: .word _GLOBAL_OFFSET_TABLE_ - 3b - 8\n"
  126. #endif
  127. "2: .word libgcc_s_resume(GOTOFF)\n"
  128. " .size _Unwind_Resume, .-_Unwind_Resume\n"
  129. );
  130. #endif
  131. _Unwind_Reason_Code
  132. __gcc_personality_v0 (_Unwind_State state,
  133. struct _Unwind_Exception *ue_header,
  134. struct _Unwind_Context *context)
  135. {
  136. if (__builtin_expect (libgcc_s_personality == NULL, 0))
  137. pthread_cancel_init ();
  138. return libgcc_s_personality (state, ue_header, context);
  139. }
  140. _Unwind_Reason_Code
  141. _Unwind_ForcedUnwind (struct _Unwind_Exception *exc, _Unwind_Stop_Fn stop,
  142. void *stop_argument)
  143. {
  144. if (__builtin_expect (libgcc_s_forcedunwind == NULL, 0))
  145. pthread_cancel_init ();
  146. return libgcc_s_forcedunwind (exc, stop, stop_argument);
  147. }
  148. _Unwind_Word
  149. _Unwind_GetCFA (struct _Unwind_Context *context)
  150. {
  151. if (__builtin_expect (libgcc_s_getcfa == NULL, 0))
  152. pthread_cancel_init ();
  153. return libgcc_s_getcfa (context);
  154. }