alpha_reloc.c revision 1.6 
1/*	$NetBSD: alpha_reloc.c,v 1.6 2002/09/05 20:08:16 mycroft Exp $	*/
2
3/*
4 * Copyright (c) 2001 Wasabi Systems, Inc.
5 * All rights reserved.
6 *
7 * Written by Jason R. Thorpe for Wasabi Systems, Inc.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 *    must display the following acknowledgement:
19 *	This product includes software developed for the NetBSD Project by
20 *	Wasabi Systems, Inc.
21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
22 *    or promote products derived from this software without specific prior
23 *    written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 * POSSIBILITY OF SUCH DAMAGE.
36 */
37
38#include <sys/types.h>
39#include <sys/stat.h>
40
41#include "rtld.h"
42#include "debug.h"
43
44#ifdef RTLD_DEBUG_ALPHA
45#define	adbg(x)		if (dodebug) xprintf x
46#else
47#define	adbg(x)		/* nothing */
48#endif
49
50void
51_rtld_setup_pltgot(const Obj_Entry *obj)
52{
53	uint32_t word0;
54
55	/*
56	 * The PLTGOT on the Alpha looks like this:
57	 *
58	 *	PLT HEADER
59	 *	.
60	 *	. 32 bytes
61	 *	.
62	 *	PLT ENTRY #0
63	 *	.
64	 *	. 12 bytes
65	 *	.
66	 *	PLT ENTRY #1
67	 *	.
68	 *	. 12 bytes
69	 *	.
70	 *	etc.
71	 *
72	 * The old-format entries look like (displacements filled in
73	 * by the linker):
74	 *
75	 *	ldah	$28, 0($31)		# 0x279f0000
76	 *	lda	$28, 0($28)		# 0x239c0000
77	 *	br	$31, plt0		# 0xc3e00000
78	 *
79	 * The new-format entries look like:
80	 *
81	 *	br	$28, plt0		# 0xc3800000
82	 *					# 0x00000000
83	 *					# 0x00000000
84	 *
85	 * What we do is fetch the first PLT entry and check to
86	 * see the first word of it matches the first word of the
87	 * old format.  If so, we use a binding routine that can
88	 * handle the old format, otherwise we use a binding routine
89	 * that handles the new format.
90	 *
91	 * Note that this is done on a per-object basis, we can mix
92	 * and match shared objects build with both the old and new
93	 * linker.
94	 */
95	word0 = *(uint32_t *)(((char *) obj->pltgot) + 32);
96	if ((word0 & 0xffff0000) == 0x279f0000) {
97		/* Old PLT entry format. */
98		adbg(("ALPHA: object %p has old PLT format\n", obj));
99		obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start_old;
100		obj->pltgot[3] = (Elf_Addr) obj;
101	} else {
102		/* New PLT entry format. */
103		adbg(("ALPHA: object %p has new PLT format\n", obj));
104		obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
105		obj->pltgot[3] = (Elf_Addr) obj;
106	}
107
108	__asm __volatile("imb");
109}
110
111int
112_rtld_relocate_nonplt_objects(obj, dodebug)
113	Obj_Entry *obj;
114	bool dodebug;
115{
116	const Elf_Rela *rela;
117
118	for (rela = obj->rela; rela < obj->relalim; rela++) {
119		Elf_Addr        *where;
120		const Elf_Sym   *def;
121		const Obj_Entry *defobj;
122		Elf_Addr         tmp;
123
124		where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
125
126		switch (ELF_R_TYPE(rela->r_info)) {
127		case R_TYPE(NONE):
128			break;
129
130		case R_TYPE(REFQUAD):
131			def = _rtld_find_symdef(rela->r_info, obj, &defobj,
132			    false);
133			if (def == NULL)
134				return -1;
135
136			tmp = (Elf_Addr)(defobj->relocbase + def->st_value) +
137		    	*where + rela->r_addend;
138			if (*where != tmp)
139				*where = tmp;
140			rdbg(dodebug, ("REFQUAD %s in %s --> %p in %s",
141		    	defobj->strtab + def->st_name, obj->path,
142		    	(void *)*where, defobj->path));
143			break;
144
145		case R_TYPE(GLOB_DAT):
146			def = _rtld_find_symdef(rela->r_info, obj, &defobj,
147			    false);
148			if (def == NULL)
149				return -1;
150
151			tmp = (Elf_Addr)(defobj->relocbase + def->st_value) +
152			    rela->r_addend;
153			if (*where != tmp)
154				*where = tmp;
155			rdbg(dodebug, ("GLOB_DAT %s in %s --> %p in %s",
156		    	defobj->strtab + def->st_name, obj->path,
157		    	(void *)*where, defobj->path));
158			break;
159
160		case R_TYPE(RELATIVE):
161		    {
162			extern Elf_Addr	_GLOBAL_OFFSET_TABLE_[];
163			extern Elf_Addr	_GOT_END_[];
164
165			/* This is the ...iffy hueristic. */
166			if (!dodebug ||
167			    (caddr_t)where < (caddr_t)_GLOBAL_OFFSET_TABLE_ ||
168			    (caddr_t)where >= (caddr_t)_GOT_END_) {
169				*where += (Elf_Addr)obj->relocbase;
170				rdbg(dodebug, ("RELATIVE in %s --> %p",
171				    obj->path, (void *)*where));
172			} else
173				rdbg(dodebug, ("RELATIVE in %s stays at %p",
174				    obj->path, (void *)*where));
175			break;
176		    }
177
178		case R_TYPE(COPY):
179			/*
180			 * These are deferred until all other relocations have
181			 * been done.  All we do here is make sure that the
182			 * COPY relocation is not in a shared library.  They
183			 * are allowed only in executable files.
184			 */
185			if (!obj->mainprog) {
186				_rtld_error(
187			"%s: Unexpected R_COPY relocation in shared library",
188				    obj->path);
189				return -1;
190			}
191			rdbg(dodebug, ("COPY (avoid in main)"));
192			break;
193
194		default:
195			def = _rtld_find_symdef(rela->r_info, obj, &defobj,
196			    true);
197			rdbg(dodebug, ("sym = %lu, type = %lu, offset = %p, "
198			    "addend = %p, contents = %p, symbol = %s",
199			    (u_long)ELF_R_SYM(rela->r_info),
200			    (u_long)ELF_R_TYPE(rela->r_info),
201			    (void *)rela->r_offset, (void *)rela->r_addend,
202			    (void *)*where,
203			    def ? defobj->strtab + def->st_name : "??"));
204			_rtld_error("%s: Unsupported relocation type %ld "
205			    "in non-PLT relocations\n",
206			    obj->path, (u_long) ELF_R_TYPE(rela->r_info));
207			return -1;
208		}
209	}
210	return 0;
211}
212