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- /* Copyright 2003 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
- The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public License as
- published by the Free Software Foundation; either version 2.1 of the
- License, or (at your option) any later version.
- The GNU C Library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Library General Public License for more details.
- You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library; see the file COPYING.LIB. If
- not, write to the Free Software Foundation, Inc., 675 Mass Ave,
- Cambridge, MA 02139, USA. */
- #ifndef _BITS_ELF_FDPIC_H
- #define _BITS_ELF_FDPIC_H
- /* These data structures are described in the FDPIC ABI extension.
- The kernel passes a process a memory map, such that for every LOAD
- segment there is an elf32_fdpic_loadseg entry. A pointer to an
- elf32_fdpic_loadmap is passed in GR8 at start-up, and a pointer to
- an additional such map is passed in GR9 for the interpreter, when
- there is one. */
- #include <elf.h>
- /* This data structure represents a PT_LOAD segment. */
- struct elf32_fdpic_loadseg
- {
- /* Core address to which the segment is mapped. */
- Elf32_Addr addr;
- /* VMA recorded in the program header. */
- Elf32_Addr p_vaddr;
- /* Size of this segment in memory. */
- Elf32_Word p_memsz;
- };
- struct elf32_fdpic_loadmap {
- /* Protocol version number, must be zero. */
- Elf32_Half version;
- /* Number of segments in this map. */
- Elf32_Half nsegs;
- /* The actual memory map. */
- struct elf32_fdpic_loadseg segs[/*nsegs*/];
- };
- struct elf32_fdpic_loadaddr {
- struct elf32_fdpic_loadmap *map;
- void *got_value;
- };
- /* Map a pointer's VMA to its corresponding address according to the
- load map. */
- inline static void *
- __reloc_pointer (void *p,
- const struct elf32_fdpic_loadmap *map)
- {
- int c;
- #if 0
- if (map->version != 0)
- /* Crash. */
- ((void(*)())0)();
- #endif
- /* No special provision is made for NULL. We don't want NULL
- addresses to go through relocation, so they shouldn't be in
- .rofixup sections, and, if they're present in dynamic
- relocations, they shall be mapped to the NULL address without
- undergoing relocations. */
- for (c = 0;
- /* Take advantage of the fact that the loadmap is ordered by
- virtual addresses. In general there will only be 2 entries,
- so it's not profitable to do a binary search. */
- c < map->nsegs && p >= (void*)map->segs[c].p_vaddr;
- c++)
- {
- /* This should be computed as part of the pointer comparison
- above, but we want to use the carry in the comparison, so we
- can't convert it to an integer type beforehand. */
- unsigned long offset = p - (void*)map->segs[c].p_vaddr;
- /* We explicitly refrain from checking for one-past-the-end.
- Zero-sized objects aren't legal, and it's expected that array
- addresses will be relocated before the addend that would make
- it one-past-the-end is added. This gives us a reasonable speed
- up, and we couldn't possibly disambiguate all cases anyway. */
- if (offset < map->segs[c].p_memsz)
- return (char*)map->segs[c].addr + offset;
- }
-
- /* We might want to crash instead. */
- return (void*)-1;
- }
- # define __RELOC_POINTER(ptr, loadaddr) \
- (__reloc_pointer ((void*)(ptr), \
- (loadaddr).map))
- #endif /* _BITS_ELF_FDPIC_H */
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