/*	$OpenBSD: md.c,v 1.6 2003/08/15 23:13:06 deraadt Exp $  */
/*	$NetBSD: md.c,v 1.6 1994/11/30 06:20:42 phil Exp $  */
/*
 * Copyright (c) 1993 Paul Kranenburg
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Paul Kranenburg.
 * 4. 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 <sys/param.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <fcntl.h>
#include <a.out.h>
#include <stab.h>
#include <string.h>

#include "ld.h"

/*
 * Put little endian VAL of size N at ADDR
 */
static void
put_num(unsigned char *addr, long val, char n)
{
	while (n--) {
		*addr++ = val;
		val >>= 8;
	}
}

/*
 * Get little endian of size N at ADDR
 */
static unsigned long
get_num(unsigned char *addr, int n)
{
	int val = 0;

	addr += (n - 1);
	while (n--)
		val = val * 256 + *addr--;

	return val;
}

/*
 * Put big endian VAL of size N at ADDR
 */
static void
put_imm(unsigned char *addr, unsigned long val, char n)
{
	addr += (n - 1);
	while (n--) {
		*addr-- = val;
		val >>= 8;
	}
}

/*
 * Get big endian of size N at ADDR
 */
static unsigned long
get_imm(unsigned char *addr, int n)
{
	int val = 0;

	while (n--)
		val = val * 256 + *addr++;

	return val;
}

/*
 * Displacements are big endian with the size
 * encoded in the two top bits:
 * Byte:	0xxxxxxx
 * Word:	10xxxxxx xxxxxxxx
 * Double word:	11xxxxxx xxxxxxxx xxxxxxxx xxxxxxxx
 */

/*
 * Signextend VAL from bit N
 */
static long
sign_extend(int	val, int n)
{
	val = val & ((1 << n) - 1);
	return (val & (1 << (n - 1))?
			val | (~((1 << n) - 1))
		:
			val
		);
}

/*
 * Put ns32k displacement VAL of size N at ADDR
 */
static void
put_disp(unsigned char *addr, long val, char n)
{
	switch (n) {
	case 1:
		if (val < -64 || val > 63)
			warnx("Byte displacement %d, out of range.", val);
		val &= 0x7f;
		*addr++ = val;
		break;
	case 2:
		if (val < -8192 || val > 8191)
			warnx("Word displacement %d, out of range.", val);
		val &= 0x3fff;
		val |= 0x8000;
		*addr++ = (val >> 8);
		*addr++ = val;
		break;
	case 4:
#if 1
		if (val < -0x1f000000 || val >= 0x20000000)
#else
		if (val < -0x20000000 || val >= 0x20000000)
#endif
			warnx("Double word displacement %d, out of range", val);
		val |= 0xc0000000;
		*addr++ = (val >> 24);
		*addr++ = (val >> 16);
		*addr++ = (val >> 8);
		*addr++ = val;
		break;
	default:
		errx(1, "internal error: putdisp: n = %d", n);
	}
}

/*
 * Get ns32k displacement size N at ADDR
 */
static unsigned long
get_disp(unsigned char *addr, int n)
{
	unsigned long Ivalue;

	Ivalue = *addr++ & 0xff;
	if (n == 0) {
		if (Ivalue & 0x80) {
			if (Ivalue & 0x40)
				n = 4;
			else
				n = 2;
		} else
			n = 1;
	}

	switch (n) {
	case 1:
		Ivalue = sign_extend(Ivalue, 7);
		break;
	case 2:
		Ivalue = sign_extend(Ivalue, 6);
		Ivalue = (Ivalue << 8) | *addr;
		break;
	case 4:
		Ivalue = sign_extend (Ivalue, 6);
		Ivalue = (Ivalue << 8) | *addr++;
		Ivalue = (Ivalue << 8) | *addr++;
		Ivalue = (Ivalue << 8) | *addr;
		break;
	default:
		errx(1, "get_disp: invalid argument %d", n);
	}
	return Ivalue;
}

/*
 * Get relocation addend corresponding to relocation record RP
 * from address ADDR
 */
long
md_get_addend(struct relocation_info *rp, unsigned char *addr)
{
	int bytes = 1 << RELOC_TARGET_SIZE(rp);

	switch (rp->r_disp) {
	case 0:
		return get_imm(addr, bytes);
	case 1:
		return get_disp(addr, bytes);
	case 2:
		return get_num(addr, bytes);
	}
}

/*
 * Put RELOCATION at ADDR according to relocation record RP.
 */
void
md_relocate(struct relocation_info *rp, long relocation, unsigned char *addr,
	    int relocatable_output)
{
	int bytes = 1 << RELOC_TARGET_SIZE(rp);

	switch (rp->r_disp) {
	case 0:
		return put_imm(addr, relocation, bytes);
	case 1:
		return put_disp(addr, relocation, bytes);
	case 2:
		return put_num(addr, relocation, bytes);
	}
#ifdef RTLD
	_cachectl (addr, bytes); /* maintain cache coherency */
#endif
}

/*
 * Machine dependent part of claim_rrs_reloc().
 * Set RRS relocation type.
 */
int
md_make_reloc(struct relocation_info *rp, struct relocation_info *r, int type)
{
	/* Relocation size */
	r->r_length = rp->r_length;

	/* Data type */
	r->r_disp = rp->r_disp;

	if (RELOC_PCREL_P(rp))
		r->r_pcrel = 1;

	if (type & RELTYPE_RELATIVE)
		r->r_relative = 1;

	if (type & RELTYPE_COPY)
		r->r_copy = 1;

	return 0;
}

/*
 * Set up a transfer from jmpslot at OFFSET (relative to the PLT table)
 * to the binder slot (which is at offset 0 of the PLT).
 */
void
md_make_jmpslot(jmpslot_t *sp, long offset, long index)
{
	/*
	 * On ns32k machines, a long branch offset is relative to
	 * the address of the branch instruction.
	 */

	put_num(sp->code, BSR, 2);
	put_disp(sp->code + 2, -offset - 1, 4);
	sp->reloc_index = index;
#ifdef RTLD
	_cachectl (sp->code, 6);	/* maintain cache coherency */
#endif
}

/*
 * Set up a "direct" transfer (ie. not through the run-time binder) from
 * jmpslot at OFFSET to ADDR. Used by `ld' when the SYMBOLIC flag is on,
 * and by `ld.so' after resolving the symbol.
 * On the ns32k, we use the BR instruction which is PC relative, so no
 * further RRS relocations will be necessary for such a jmpslot.
 */
void
md_fix_jmpslot(jmpslot_t *sp, long offset, u_long addr)
{
	put_num(sp->code, BR, 2);
	put_disp(sp->code + 2, addr - offset - 1, 4);
	sp->reloc_index = 0;
#ifdef RTLD
	_cachectl (sp->code, 6);	/* maintain cache coherency */
#endif
}

/*
 * Update the relocation record for a RRS jmpslot.
 */
void
md_make_jmpreloc(struct relocation_info *rp, struct relocation_info *r,
		 int type)
{
	jmpslot_t	*sp;

	/*
	 * Fix relocation address to point to the correct
	 * location within this jmpslot.
	 */
	r->r_address++;

	/* Relocation size */
	r->r_length = 2;

	/* Data type */
	r->r_disp = 1;

	/* Set relocation type */
	r->r_jmptable = 1;

	if (type & RELTYPE_RELATIVE)
		r->r_relative = 1;
}

/*
 * Set relocation type for a RRS GOT relocation.
 */
void
md_make_gotreloc(struct relocation_info *rp, struct relocation_info *r,
		 int type)
{
	r->r_baserel = 1;
	if (type & RELTYPE_RELATIVE)
		r->r_relative = 1;

	/* Relocation size */
	r->r_length = 2;

	/* Data type */
	r->r_disp = 2;
}

/*
 * Set relocation type for a RRS copy operation.
 */
void
md_make_cpyreloc(struct relocation_info *rp, struct relocation_info *r)
{
	/* Relocation size */
	r->r_length = 2;

	/* Data type */
	r->r_disp = 2;

	r->r_copy = 1;
}

void
md_set_breakpoint(long where, long *savep)
{
	*savep = *(long *)where;
	*(short *)where = BPT;
}

#ifndef RTLD
/*
 * Initialize (output) exec header such that useful values are
 * obtained from subsequent N_*() macro evaluations.
 */
void
md_init_header(struct exec *hp, int magic, int flags)
{
	if (oldmagic)
		hp->a_midmag = oldmagic;
	else
		N_SETMAGIC((*hp), magic, MID_MACHINE, flags);

	/* TEXT_START depends on the value of outheader.a_entry.  */
	if (!(link_mode & SHAREABLE))
		hp->a_entry = PAGSIZ;
}
#endif /* RTLD */


#ifdef NEED_SWAP
/*
 * Byte swap routines for cross-linking.
 */

void
md_swapin_exec_hdr(struct exec *h)
{
	int skip = 0;

	if (!N_BADMAG(*h))
		skip = 1;

	swap_longs((long *)h + skip, sizeof(*h)/sizeof(long) - skip);
}

void
md_swapout_exec_hdr(struct exec *h)
{
	/* NetBSD/OpenBSD: Always leave magic alone */
	int skip = 1;
#if 0
	if (N_GETMAGIC(*h) == OMAGIC)
		skip = 0;
#endif

	swap_longs((long *)h + skip, sizeof(*h)/sizeof(long) - skip);
}


void
md_swapin_reloc(struct relocation_info *r, int n)
{
	int	bits;

	for (; n; n--, r++) {
		r->r_address = md_swap_long(r->r_address);
		bits = ((int *)r)[1];
		r->r_symbolnum = md_swap_long(bits) & 0xffffff;
		bits = ((unsigned char *)r)[7];
		r->r_pcrel = ((bits >> 7) & 1);
		r->r_length = ((bits >> 5) & 3);
		r->r_extern = ((bits >> 4) & 1);
		r->r_baserel = ((bits >> 3) & 1);
		r->r_jmptable = ((bits >> 2) & 1);
		r->r_relative = ((bits >> 1) & 1);
#ifdef N_SIZE
		r->r_copy = (bits & 1);
#endif
	}
}

void
md_swapout_reloc(struct relocation_info *r, int n)
{
	int	bits;

	for (; n; n--, r++) {
		r->r_address = md_swap_long(r->r_address);
		((int *)r)[1] = md_swap_long(r->r_symbolnum & 0xffffff00);
		bits = ((r->r_pcrel << 7) & 0x80);
		bits |= ((r->r_length << 5) & 0x60);
		bits |= ((r->r_extern << 4) & 0x10);
		bits |= ((r->r_baserel << 3) & 8);
		bits |= ((r->r_jmptable << 2) & 4);
		bits |= ((r->r_relative << 1) & 2);
#ifdef N_SIZE
		bits |= (r->r_copy & 1);
#endif
		((unsigned char *)r)[7] = bits;
	}
}

void
md_swapout_jmpslot(jmpslot_t *j, int n)
{
	for (; n; n--, j++) {
		j->opcode = md_swap_short(j->opcode);
		j->addr[0] = md_swap_short(j->addr[0]);
		j->addr[1] = md_swap_short(j->addr[1]);
		j->reloc_index = md_swap_short(j->reloc_index);
	}
}

#endif /* NEED_SWAP */