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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <libelf.h>
#include <sys/reg.h>
#include <rtld_db.h>
#include "_rtld_db.h"
#include "msg.h"
/*
* On amd64, basically, a PLT entry looks like this:
*
* 0x00 ff 25 00 00 00 00 jmpq *func@got(%rip) ; jmp GOT[N]
* 0x06 68 01 00 00 00 pushq $0x1 ; push index
* 0x0b e9 00 00 00 00 jmpq .plt0 ; jmp plt[0]
* 0x10 ...
*
* The first time around GOT[N] contains address of pushq; this forces
* first time resolution to go thru PLT's first entry (which is a call)
* The nth time around, the GOT[N] actually contains the resolved
* address of the symbol(name), so the jmp is direct
*/
/* ARGSUSED 3 */
rd_err_e
plt64_resolution(rd_agent_t *rap, psaddr_t pc, lwpid_t lwpid,
psaddr_t pltbase, rd_plt_info_t *rpi)
{
uint32_t pcrel;
psaddr_t destaddr;
psaddr_t pltoff, pltaddr;
if (rtld_db_version >= RD_VERSION3) {
rpi->pi_flags = 0;
rpi->pi_baddr = 0;
}
pltoff = pc - pltbase;
pltaddr = pltbase +
((pltoff / M_PLT_ENTSIZE) * M_PLT_ENTSIZE);
/*
* This is the target of the jmp instruction
*/
if (ps_pread(rap->rd_psp, pltaddr + 2, (char *)&pcrel,
sizeof (pcrel)) != PS_OK) {
LOG(ps_plog(MSG_ORIG(MSG_DB_READFAIL_2), EC_ADDR(pltaddr + 2)));
return (RD_ERR);
}
/*
* the offset to the GOT table entry is
* PC-relative.
*/
destaddr = pcrel + pltaddr + 6;
/*
* Find out what's pointed to by @OFFSET_INTO_GOT
*/
if (ps_pread(rap->rd_psp, destaddr, (char *)&destaddr,
sizeof (destaddr)) != PS_OK) {
LOG(ps_plog(MSG_ORIG(MSG_DB_READFAIL_2), EC_ADDR(destaddr)));
return (RD_ERR);
}
if (destaddr == (pltaddr + 6)) {
rd_err_e rerr;
/*
* If GOT[ind] points to PLT+6 then this is the first
* time through this PLT.
*/
if ((rerr = rd_binder_exit_addr(rap, MSG_ORIG(MSG_SYM_RTBIND),
&(rpi->pi_target))) != RD_OK) {
return (rerr);
}
rpi->pi_skip_method = RD_RESOLVE_TARGET_STEP;
rpi->pi_nstep = 1;
} else {
/*
* This is the n'th time through and GOT[ind] points
* to the final destination.
*/
rpi->pi_skip_method = RD_RESOLVE_STEP;
rpi->pi_nstep = 1;
rpi->pi_target = 0;
if (rtld_db_version >= RD_VERSION3) {
rpi->pi_flags |= RD_FLG_PI_PLTBOUND;
rpi->pi_baddr = destaddr;
}
}
return (RD_OK);
}
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