1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #include <libelf.h>
28 #include <sys/reg.h>
29 #include <rtld_db.h>
30 #include "_rtld_db.h"
31 #include "msg.h"
32
33
34 /*
35 * On amd64, basically, a PLT entry looks like this:
36 *
37 * 0x00 ff 25 00 00 00 00 jmpq *func@got(%rip) ; jmp GOT[N]
38 * 0x06 68 01 00 00 00 pushq $0x1 ; push index
39 * 0x0b e9 00 00 00 00 jmpq .plt0 ; jmp plt[0]
40 * 0x10 ...
41 *
42 * The first time around GOT[N] contains address of pushq; this forces
43 * first time resolution to go thru PLT's first entry (which is a call)
44 * The nth time around, the GOT[N] actually contains the resolved
45 * address of the symbol(name), so the jmp is direct
46 */
47 /* ARGSUSED 3 */
48 rd_err_e
plt64_resolution(rd_agent_t * rap,psaddr_t pc,lwpid_t lwpid,psaddr_t pltbase,rd_plt_info_t * rpi)49 plt64_resolution(rd_agent_t *rap, psaddr_t pc, lwpid_t lwpid,
50 psaddr_t pltbase, rd_plt_info_t *rpi)
51 {
52 uint32_t pcrel;
53 psaddr_t destaddr;
54 psaddr_t pltoff, pltaddr;
55
56
57 if (rtld_db_version >= RD_VERSION3) {
58 rpi->pi_flags = 0;
59 rpi->pi_baddr = 0;
60 }
61
62 pltoff = pc - pltbase;
63 pltaddr = pltbase +
64 ((pltoff / M_PLT_ENTSIZE) * M_PLT_ENTSIZE);
65 /*
66 * This is the target of the jmp instruction
67 */
68 if (ps_pread(rap->rd_psp, pltaddr + 2, (char *)&pcrel,
69 sizeof (pcrel)) != PS_OK) {
70 LOG(ps_plog(MSG_ORIG(MSG_DB_READFAIL_2), EC_ADDR(pltaddr + 2)));
71 return (RD_ERR);
72 }
73
74 /*
75 * the offset to the GOT table entry is
76 * PC-relative.
77 */
78 destaddr = pcrel + pltaddr + 6;
79
80 /*
81 * Find out what's pointed to by @OFFSET_INTO_GOT
82 */
83 if (ps_pread(rap->rd_psp, destaddr, (char *)&destaddr,
84 sizeof (destaddr)) != PS_OK) {
85 LOG(ps_plog(MSG_ORIG(MSG_DB_READFAIL_2), EC_ADDR(destaddr)));
86 return (RD_ERR);
87 }
88 if (destaddr == (pltaddr + 6)) {
89 rd_err_e rerr;
90 /*
91 * If GOT[ind] points to PLT+6 then this is the first
92 * time through this PLT.
93 */
94 if ((rerr = rd_binder_exit_addr(rap, MSG_ORIG(MSG_SYM_RTBIND),
95 &(rpi->pi_target))) != RD_OK) {
96 return (rerr);
97 }
98 rpi->pi_skip_method = RD_RESOLVE_TARGET_STEP;
99 rpi->pi_nstep = 1;
100 } else {
101 /*
102 * This is the n'th time through and GOT[ind] points
103 * to the final destination.
104 */
105 rpi->pi_skip_method = RD_RESOLVE_STEP;
106 rpi->pi_nstep = 1;
107 rpi->pi_target = 0;
108 if (rtld_db_version >= RD_VERSION3) {
109 rpi->pi_flags |= RD_FLG_PI_PLTBOUND;
110 rpi->pi_baddr = destaddr;
111 }
112 }
113
114 return (RD_OK);
115 }
116