/*

 * libhugetlbfs - Easy use of Linux hugepages

 * Copyright (C) 2008 Adam Litke, IBM Corporation.

 *

 * This 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.

 *

 * This 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include <elf.h>

#include <link.h>

#include "libhugetlbfs_internal.h"

/*

 * The powerpc 64-bit ELF ABI defines the location and size of the plt as

 * follows (see the ELF ABI and powerpc64 supplement for details):

 *

 * Location:   (data segment p_vaddr) + (data segment p_filesz)

 * Size:       (dynamic symbol table DT_PTRELSZ entry) + 24

 *

 * plt entries have likely been initialized when the libhugetlbfs remapping

 * code runs, we must copy these entries when preparing the data segment.  Tell

 * the arch-independent code how many bytes to copy.

 */

ElfW(Word) plt_extrasz(ElfW(Dyn) *dyntab)

{

	int i;

	ElfW(Word) pltrelsz = 0;

	/* Find the needed information in the dynamic section */

	for (i = 0; dyntab[i].d_tag != DT_NULL; i++)

		if (dyntab[i].d_tag == DT_PLTRELSZ)

			pltrelsz = dyntab[i].d_un.d_val;

	/* pltrelsz indicates the size of all plt entries used to cache

	 * symbol lookups, but does not include the reserved entry at PLT[0].

	 * 24 bytes is the ABI-defined size of a plt entry.

	 */

	if (pltrelsz)

		return pltrelsz + 24;

	else

		return 0;

}