stackinfo.h 1.6 KB

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  1. /* Copyright (C) 1999-2026 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. The GNU C Library is free software; you can redistribute it and/or
  4. modify it under the terms of the GNU Lesser General Public
  5. License as published by the Free Software Foundation; either
  6. version 2.1 of the License, or (at your option) any later version.
  7. The GNU C Library is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10. Lesser General Public License for more details.
  11. You should have received a copy of the GNU Lesser General Public
  12. License along with the GNU C Library; if not, see
  13. <https://www.gnu.org/licenses/>. */
  14. /* This file contains a bit of information about the stack allocation
  15. of the processor. */
  16. #ifndef _STACKINFO_H
  17. #define _STACKINFO_H 1
  18. #include <elf.h>
  19. /* On x86 the stack grows down. */
  20. #define _STACK_GROWS_DOWN 1
  21. /* Default to an executable stack. PROT_EXEC can be overridden if PT_GNU_STACK
  22. * is present, but it is presumed absent. */
  23. #define DEFAULT_STACK_PROT_PERMS (PROT_READ|PROT_WRITE|PROT_EXEC)
  24. /* Access to the stack pointer. The macros are used in alloca_account
  25. for which they need to act as barriers as well, hence the additional
  26. (unnecessary) parameters. */
  27. #define stackinfo_get_sp() \
  28. ({ void *p__; asm volatile ("mov %%esp, %0" : "=r" (p__)); p__; })
  29. #define stackinfo_sub_sp(ptr) \
  30. ({ ptrdiff_t d__; \
  31. asm volatile ("sub %%esp, %0" : "=r" (d__) : "0" (ptr)); \
  32. d__; })
  33. #endif /* stackinfo.h */