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[unix-history] / gnu / usr.bin / ld / i386 / md.c
/*
* 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 withough 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.
*
* $Id: md.c,v 1.7 1994/01/03 18:35:35 davidg Exp $
*/
#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"
int netzmagic = 0;
/*
* Get relocation addend corresponding to relocation record RP
* from address ADDR
*/
long
md_get_addend(rp, addr)
struct relocation_info *rp;
unsigned char *addr;
{
switch (RELOC_TARGET_SIZE(rp)) {
case 0:
return get_byte(addr);
break;
case 1:
return get_short(addr);
break;
case 2:
return get_long(addr);
break;
}
}
/*
* Put RELOCATION at ADDR according to relocation record RP.
*/
void
md_relocate(rp, relocation, addr, relocatable_output)
struct relocation_info *rp;
long relocation;
unsigned char *addr;
{
switch (RELOC_TARGET_SIZE(rp)) {
case 0:
put_byte(addr, relocation);
break;
case 1:
put_short(addr, relocation);
break;
case 2:
put_long(addr, relocation);
break;
default:
fatal("Unsupported relocation size: %x", RELOC_TARGET_SIZE(rp));
}
}
/*
* Initialize (output) exec header such that useful values are
* obtained from subsequent N_*() macro evaluations.
*/
void
md_init_header(hp, magic, flags)
struct exec *hp;
int magic, flags;
{
if (!netzmagic && (magic == ZMAGIC)) {
hp->a_midmag = magic;
} else {
if (netzmagic)
N_SETMAGIC_NET((*hp), magic, MID_I386, flags);
else
N_SETMAGIC((*hp), magic, MID_I386, flags);
}
/* TEXT_START depends on the value of outheader.a_entry. */
if (!(link_mode & SHAREABLE)) /*WAS: if (entry_symbol) */
hp->a_entry = PAGSIZ;
}
/*
* Machine dependent part of claim_rrs_reloc().
* Set RRS relocation type.
*/
int
md_make_reloc(rp, r, type)
struct relocation_info *rp, *r;
int type;
{
/* Relocation size */
r->r_length = rp->r_length;
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(sp, offset, index)
jmpslot_t *sp;
long offset;
long index;
{
/*
* i386 PC-relative "fixed point" is located right after the
* instruction it pertains to.
*/
u_long fudge = - (sizeof(sp->opcode) + sizeof(sp->addr) + offset);
sp->opcode = CALL;
#if 0
sp->addr = fudge;
#else
sp->addr[0] = fudge & 0xffff;
sp->addr[1] = fudge >> 16;
#endif
sp->reloc_index = index;
}
/*
* 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 i386, we use the JMP instruction which is PC relative, so no
* further RRS relocations will be necessary for such a jmpslot.
*/
void
md_fix_jmpslot(sp, offset, addr)
jmpslot_t *sp;
long offset;
u_long addr;
{
u_long fudge = addr - (sizeof(sp->opcode) + sizeof(sp->addr) + offset);
sp->opcode = JUMP;
#if 0
sp->addr = fudge;
#else
sp->addr[0] = fudge & 0xffff;
sp->addr[1] = fudge >> 16;
#endif
sp->reloc_index = 0;
}
/*
* Update the relocation record for a RRS jmpslot.
*/
void
md_make_jmpreloc(rp, r, type)
struct relocation_info *rp, *r;
int type;
{
jmpslot_t *sp;
/*
* Fix relocation address to point to the correct
* location within this jmpslot.
*/
r->r_address += sizeof(sp->opcode);
/* Relocation size */
r->r_length = 2;
/* 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(rp, r, type)
struct relocation_info *rp, *r;
int type;
{
r->r_baserel = 1;
if (type & RELTYPE_RELATIVE)
r->r_relative = 1;
/* Relocation size */
r->r_length = 2;
}
/*
* Set relocation type for a RRS copy operation.
*/
void
md_make_cpyreloc(rp, r)
struct relocation_info *rp, *r;
{
/* Relocation size */
r->r_length = 2;
r->r_copy = 1;
}
void
md_set_breakpoint(where, savep)
long where;
long *savep;
{
*savep = *(long *)where;
*(char *)where = TRAP;
}
#ifdef NEED_SWAP
/*
* Byte swap routines for cross-linking.
*/
void
md_swapin_exec_hdr(h)
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(h)
struct exec *h;
{
/* NetBSD: 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(r, n)
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 & 0xffffff00);
r->r_pcrel = (bits & 1);
r->r_length = ((bits >> 1) & 3);
r->r_extern = ((bits >> 3) & 1);
r->r_baserel = ((bits >> 4) & 1);
r->r_jmptable = ((bits >> 5) & 1);
r->r_relative = ((bits >> 6) & 1);
#ifdef N_SIZE
r->r_copy = ((bits >> 7) & 1);
#endif
}
}
void
md_swapout_reloc(r, n)
struct relocation_info *r;
int n;
{
int bits;
for (; n; n--, r++) {
r->r_address = md_swap_long(r->r_address);
bits = (md_swap_long(r->r_symbolnum) & 0xffffff00);
bits |= (r->r_pcrel & 1);
bits |= ((r->r_length << 1) & 6);
bits |= ((r->r_extern << 3) & 8);
bits |= ((r->r_baserel << 4) & 0x10);
bits |= ((r->r_jmptable << 5) & 0x20);
bits |= ((r->r_relative << 6) & 0x40);
#ifdef N_SIZE
bits |= ((r->r_copy << 7) & 0x80);
#endif
((int *)r)[1] = bits;
}
}
void
md_swapout_jmpslot(j, n)
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 */
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.