/*	$NetBSD: ppc_reloc.c,v 1.10 2001/09/10 06:09:41 mycroft Exp $	*/

/*-
 * Copyright (C) 1998	Tsubai Masanari
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <machine/cpu.h>

#include "debug.h"
#include "rtld.h"

caddr_t _rtld_bind_powerpc __P((Obj_Entry *, Elf_Word));
void _rtld_powerpc_pltcall __P((Elf_Word));
void _rtld_powerpc_pltresolve __P((Elf_Word, Elf_Word));

#define ha(x) ((((u_int32_t)(x) & 0x8000) ? \
			((u_int32_t)(x) + 0x10000) : (u_int32_t)(x)) >> 16)
#define l(x) ((u_int32_t)(x) & 0xffff)

/*
 * Bind a pltgot slot indexed by reloff.
 */
caddr_t
_rtld_bind_powerpc(obj, reloff)
	Obj_Entry *obj;
	Elf_Word reloff;
{
	const Elf_Rela *rela;
	caddr_t		addr;

	if (reloff < 0 || reloff >= 0x8000) {
		dbg(("_rtld_bind_powerpc: broken reloff %x", reloff));
		_rtld_die();
	}

	rela = obj->pltrela + reloff;

	if (_rtld_relocate_plt_object(obj, rela, &addr, true, true) < 0)
		_rtld_die();

	return addr;
}

/*
 * Make a pltgot slot.
 * Initial value is "pltresolve" unless bind_now is true.
 */
int
_rtld_relocate_plt_object(
	Obj_Entry *obj,
	const Elf_Rela *rela,
	caddr_t *addrp,
	bool bind_now,
	bool dodebug)
{
	Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset);
	int distance;

	if (bind_now) {
		const Elf_Sym *def;
		const Obj_Entry *defobj;
		Elf_Addr value;

		assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT));

		def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj,
					&defobj, true);
		if (def == NULL)
			return (-1);

		value = (Elf_Addr)(defobj->relocbase + def->st_value);
		distance = value - (Elf_Addr)where;

		if (abs(distance) < 32*1024*1024) {	/* inside 32MB? */
			/* b	value	# branch directly */
			*where = 0x48000000 | (distance & 0x03fffffc);
			__syncicache(where, 4);
		} else {
			Elf_Addr *pltcall, *jmptab;
			int N = obj->pltrelalim - obj->pltrela;
			int reloff = rela - obj->pltrela;
	
			if (reloff < 0 || reloff >= 0x8000)
				return (-1);
	
			pltcall = obj->pltgot;
	
			jmptab = pltcall + 18 + N * 2;
			jmptab[reloff] = value;

			distance = (Elf_Addr)pltcall - (Elf_Addr)(where + 1);
	
			/* li	r11,reloff */
			/* b	pltcall		# use pltcall routine */
			where[0] = 0x39600000 | reloff;
			where[1] = 0x48000000 | (distance & 0x03fffffc);
			__syncicache(where, 8);
		}

		if (addrp != NULL)
			*addrp = (caddr_t)value;

		return (0);
	} else {
		Elf_Addr *pltresolve;
		int reloff = rela - obj->pltrela;

		if (reloff < 0 || reloff >= 0x8000)
			return (-1);

		pltresolve = obj->pltgot + 8;

		distance = (Elf_Addr)pltresolve - (Elf_Addr)(where + 1);

	        /* li	r11,reloff */
		/* b	pltresolve   */
		where[0] = 0x39600000 | reloff;
		where[1] = 0x48000000 | (distance & 0x03fffffc);
		/* __syncicache(where, 8); */
	}

	return 0;
}

/*
 * Setup the plt glue routines.
 */
#define PLTCALL_SIZE	20
#define PLTRESOLVE_SIZE	24

void
_rtld_setup_powerpc_plt(obj)
	const Obj_Entry * obj;
{
	Elf_Word *pltcall, *pltresolve;
	Elf_Word *jmptab;
	int N = obj->pltrelalim - obj->pltrela;

	pltcall = obj->pltgot;

	memcpy(pltcall, _rtld_powerpc_pltcall, PLTCALL_SIZE);
	jmptab = pltcall + 18 + N * 2;
	pltcall[1] |= ha(jmptab);
	pltcall[2] |= l(jmptab);

	pltresolve = obj->pltgot + 8;

	memcpy(pltresolve, _rtld_powerpc_pltresolve, PLTRESOLVE_SIZE);
	pltresolve[0] |= ha(_rtld_bind_start);
	pltresolve[1] |= l(_rtld_bind_start);
	pltresolve[3] |= ha(obj);
	pltresolve[4] |= l(obj);

	__syncicache(pltcall, 72 + N * 8);
}