/*	$NetBSD: kobj_machdep.c,v 1.3 2011/06/12 01:29:58 mrg Exp $	*/

/*-
 * Copyright (c) 1999, 2002, 2008 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Paul Kranenburg and by Charles M. Hannum.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``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 FOUNDATION OR CONTRIBUTORS
 * 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.
 */

#define	ELFSIZE		ARCH_ELFSIZE

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kobj.h>
#include <sys/exec.h>
#include <sys/exec_elf.h>

/*
 * The following table holds for each relocation type:
 *	- the width in bits of the memory location the relocation
 *	  applies to (not currently used)
 *	- the number of bits the relocation value must be shifted to the
 *	  right (i.e. discard least significant bits) to fit into
 *	  the appropriate field in the instruction word.
 *	- flags indicating whether
 *		* the relocation involves a symbol
 *		* the relocation is relative to the current position
 *		* the relocation is for a GOT entry
 *		* the relocation is relative to the load address
 *
 */
#define _RF_S		0x80000000		/* Resolve symbol */
#define _RF_A		0x40000000		/* Use addend */
#define _RF_P		0x20000000		/* Location relative */
#define _RF_G		0x10000000		/* GOT offset */
#define _RF_B		0x08000000		/* Load address relative */
#define _RF_U		0x04000000		/* Unaligned */
#define _RF_SZ(s)	(((s) & 0xff) << 8)	/* memory target size */
#define _RF_RS(s)	( (s) & 0xff)		/* right shift */
static const int reloc_target_flags[] = {
	0,							/* NONE */
	_RF_S|_RF_A|		_RF_SZ(8)  | _RF_RS(0),		/* RELOC_8 */
	_RF_S|_RF_A|		_RF_SZ(16) | _RF_RS(0),		/* RELOC_16 */
	_RF_S|_RF_A|		_RF_SZ(32) | _RF_RS(0),		/* RELOC_32 */
	_RF_S|_RF_A|_RF_P|	_RF_SZ(8)  | _RF_RS(0),		/* DISP_8 */
	_RF_S|_RF_A|_RF_P|	_RF_SZ(16) | _RF_RS(0),		/* DISP_16 */
	_RF_S|_RF_A|_RF_P|	_RF_SZ(32) | _RF_RS(0),		/* DISP_32 */
	_RF_S|_RF_A|_RF_P|	_RF_SZ(32) | _RF_RS(2),		/* WDISP_30 */
	_RF_S|_RF_A|_RF_P|	_RF_SZ(32) | _RF_RS(2),		/* WDISP_22 */
	_RF_S|_RF_A|		_RF_SZ(32) | _RF_RS(10),	/* HI22 */
	_RF_S|_RF_A|		_RF_SZ(32) | _RF_RS(0),		/* 22 */
	_RF_S|_RF_A|		_RF_SZ(32) | _RF_RS(0),		/* 13 */
	_RF_S|_RF_A|		_RF_SZ(32) | _RF_RS(0),		/* LO10 */
	_RF_G|			_RF_SZ(32) | _RF_RS(0),		/* GOT10 */
	_RF_G|			_RF_SZ(32) | _RF_RS(0),		/* GOT13 */
	_RF_G|			_RF_SZ(32) | _RF_RS(10),	/* GOT22 */
	_RF_S|_RF_A|_RF_P|	_RF_SZ(32) | _RF_RS(0),		/* PC10 */
	_RF_S|_RF_A|_RF_P|	_RF_SZ(32) | _RF_RS(10),	/* PC22 */
	      _RF_A|_RF_P|	_RF_SZ(32) | _RF_RS(2),		/* WPLT30 */
				_RF_SZ(32) | _RF_RS(0),		/* COPY */
	_RF_S|_RF_A|		_RF_SZ(32) | _RF_RS(0),		/* GLOB_DAT */
				_RF_SZ(32) | _RF_RS(0),		/* JMP_SLOT */
	      _RF_A|	_RF_B|	_RF_SZ(32) | _RF_RS(0),		/* RELATIVE */
	_RF_S|_RF_A|	_RF_U|	_RF_SZ(32) | _RF_RS(0),		/* UA_32 */
};

#ifdef RTLD_DEBUG_RELOC
static const char *reloc_names[] = {
	"NONE", "RELOC_8", "RELOC_16", "RELOC_32", "DISP_8",
	"DISP_16", "DISP_32", "WDISP_30", "WDISP_22", "HI22",
	"22", "13", "LO10", "GOT10", "GOT13",
	"GOT22", "PC10", "PC22", "WPLT30", "COPY",
	"GLOB_DAT", "JMP_SLOT", "RELATIVE", "UA_32"
};
#endif

#define RELOC_RESOLVE_SYMBOL(t)		((reloc_target_flags[t] & _RF_S) != 0)
#define RELOC_PC_RELATIVE(t)		((reloc_target_flags[t] & _RF_P) != 0)
#define RELOC_BASE_RELATIVE(t)		((reloc_target_flags[t] & _RF_B) != 0)
#define RELOC_UNALIGNED(t)		((reloc_target_flags[t] & _RF_U) != 0)
#define RELOC_USE_ADDEND(t)		((reloc_target_flags[t] & _RF_A) != 0)
#define RELOC_TARGET_SIZE(t)		((reloc_target_flags[t] >> 8) & 0xff)
#define RELOC_VALUE_RIGHTSHIFT(t)	(reloc_target_flags[t] & 0xff)

static const int reloc_target_bitmask[] = {
#define _BM(x)	(~(-(1ULL << (x))))
	0,				/* NONE */
	_BM(8), _BM(16), _BM(32),	/* RELOC_8, _16, _32 */
	_BM(8), _BM(16), _BM(32),	/* DISP8, DISP16, DISP32 */
	_BM(30), _BM(22),		/* WDISP30, WDISP22 */
	_BM(22), _BM(22),		/* HI22, _22 */
	_BM(13), _BM(10),		/* RELOC_13, _LO10 */
	_BM(10), _BM(13), _BM(22),	/* GOT10, GOT13, GOT22 */
	_BM(10), _BM(22),		/* _PC10, _PC22 */  
	_BM(30), 0,			/* _WPLT30, _COPY */
	-1, -1, -1,			/* _GLOB_DAT, JMP_SLOT, _RELATIVE */
	_BM(32)				/* _UA32 */
#undef _BM
};
#define RELOC_VALUE_BITMASK(t)	(reloc_target_bitmask[t])

int
kobj_reloc(kobj_t ko, uintptr_t relocbase, const void *data,
	   bool isrela, bool local)
{
	const Elf_Rela *rela;
	Elf_Addr *where;
	Elf_Word value, mask;
	uintptr_t tmp, addr;
	u_int symidx, type;

	rela = data;
	where = (Elf_Addr *) (relocbase + rela->r_offset);
	symidx = ELF_R_SYM(rela->r_info);
	type = ELF_R_TYPE(rela->r_info);
	value = rela->r_addend;

	if (type == R_TYPE(NONE))
		return 0;

	if (!isrela) {
		printf("kobj_reloc: only support RELA relocations\n");
		return -1;
	}

	if (type == R_TYPE(JMP_SLOT) || type == R_TYPE(COPY) ||
	    type > R_TYPE(6)) {
		printf("kobj_reloc: unexpected reloc type %d\n", type);
		return -1;
	}

	if (type == R_TYPE(RELATIVE)) {
		*where += (Elf_Addr)(relocbase + value);
		return 0;
	}

	if (RELOC_RESOLVE_SYMBOL(type)) {
		addr = kobj_sym_lookup(ko, symidx);
		if (addr == 0)
			return -1;
		value += addr;
	}

	if (RELOC_PC_RELATIVE(type)) {
		value -= (Elf_Word)where;
	}

	if (RELOC_BASE_RELATIVE(type)) {
		value += (Elf_Word)(relocbase + *where);
	}

	mask = RELOC_VALUE_BITMASK(type);
	value >>= RELOC_VALUE_RIGHTSHIFT(type);
	value &= mask;

	if (RELOC_UNALIGNED(type)) {
		/* Handle unaligned relocations. */
		char *ptr = (char *)where;
		int i, size = RELOC_TARGET_SIZE(type)/8;

		/* Read it in one byte at a time. */
		for (i = 0, tmp = 0; i < size; i++)
			tmp = (tmp << 8) | ptr[i];

		tmp &= ~mask;
		tmp |= value;

		/* Write it back out. */
		for (i=0; i<size; i++)
			ptr[i] = ((tmp >> (8*i)) & 0xff);

	} else {
		*where &= ~mask;
		*where |= value;
	}

	return 0;
}

int
kobj_machdep(kobj_t ko, void *base, size_t size, bool load)
{

	return 0;
}
