1/*	$NetBSD: ppc_reloc.c,v 1.48 2011/03/12 07:43:53 matt Exp $	*/
2
3/*-
4 * Copyright (C) 1998	Tsubai Masanari
5 * Portions copyright 2002 Charles M. Hannum <root@ihack.net>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. The name of the author may not be used to endorse or promote products
17 *    derived from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include <sys/cdefs.h>
32#ifndef lint
33__RCSID("$NetBSD: ppc_reloc.c,v 1.48 2011/03/12 07:43:53 matt Exp $");
34#endif /* not lint */
35
36#include <stdarg.h>
37#include <stdio.h>
38#include <stdlib.h>
39#include <string.h>
40#include <sys/types.h>
41#include <machine/cpu.h>
42
43#include "debug.h"
44#include "rtld.h"
45
46void _rtld_powerpc_pltcall(Elf_Word);
47void _rtld_powerpc_pltresolve(Elf_Word, Elf_Word);
48
49#define ha(x) ((((u_int32_t)(x) & 0x8000) ? \
50			((u_int32_t)(x) + 0x10000) : (u_int32_t)(x)) >> 16)
51#define l(x) ((u_int32_t)(x) & 0xffff)
52
53void _rtld_bind_bssplt_start(void);
54void _rtld_bind_secureplt_start(void);
55void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr);
56caddr_t _rtld_bind(const Obj_Entry *, Elf_Word);
57static int _rtld_relocate_plt_object(const Obj_Entry *,
58    const Elf_Rela *, int, Elf_Addr *);
59
60/*
61 * The PPC PLT format consists of three sections:
62 * (1) The "pltcall" and "pltresolve" glue code.  This is always 18 words.
63 * (2) The code part of the PLT entries.  There are 2 words per entry for
64 *     up to 8192 entries, then 4 words per entry for any additional entries.
65 * (3) The data part of the PLT entries, comprising a jump table.
66 *     This section is half the size of the second section (ie. 1 or 2 words
67 *     per entry).
68 */
69
70/*
71 * Setup the plt glue routines (for bss-plt).
72 */
73#define PLTCALL_SIZE	20
74#define PLTRESOLVE_SIZE	24
75
76void
77_rtld_setup_pltgot(const Obj_Entry *obj)
78{
79	/*
80	 * Secure-PLT is much more sane.
81	 */
82	if (obj->gotptr != NULL) {
83		obj->gotptr[1] = (Elf_Addr) _rtld_bind_secureplt_start;
84		obj->gotptr[2] = (Elf_Addr) obj;
85		dbg(("obj %s secure-plt gotptr=%p start=%p obj=%p",
86		    obj->path, obj->gotptr,
87		    (void *) obj->gotptr[1], (void *) obj->gotptr[2]));
88	} else {
89		Elf_Word *pltcall, *pltresolve;
90		Elf_Word *jmptab;
91		int N = obj->pltrelalim - obj->pltrela;
92
93		/* Entries beyond 8192 take twice as much space. */
94		if (N > 8192)
95			N += N-8192;
96
97		dbg(("obj %s bss-plt pltgot=%p jmptab=%u start=%p obj=%p",
98		    obj->path, obj->pltgot, 18 + N * 2,
99		    _rtld_bind_bssplt_start, obj));
100
101		pltcall = obj->pltgot;
102		jmptab = pltcall + 18 + N * 2;
103
104		memcpy(pltcall, _rtld_powerpc_pltcall, PLTCALL_SIZE);
105		pltcall[1] |= ha(jmptab);
106		pltcall[2] |= l(jmptab);
107
108		pltresolve = obj->pltgot + 8;
109
110		memcpy(pltresolve, _rtld_powerpc_pltresolve, PLTRESOLVE_SIZE);
111		pltresolve[0] |= ha(_rtld_bind_bssplt_start);
112		pltresolve[1] |= l(_rtld_bind_bssplt_start);
113		pltresolve[3] |= ha(obj);
114		pltresolve[4] |= l(obj);
115
116		/*
117		 * Invalidate the icache for only the code part of the PLT
118		 * (and not the jump table at the end).
119		 */
120		__syncicache(pltcall, (char *)jmptab - (char *)pltcall);
121	}
122}
123
124void
125_rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase)
126{
127	const Elf_Rela *rela = 0, *relalim;
128	Elf_Addr relasz = 0;
129	Elf_Addr *where;
130
131	for (; dynp->d_tag != DT_NULL; dynp++) {
132		switch (dynp->d_tag) {
133		case DT_RELA:
134			rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr);
135			break;
136		case DT_RELASZ:
137			relasz = dynp->d_un.d_val;
138			break;
139		}
140	}
141	relalim = (const Elf_Rela *)((const uint8_t *)rela + relasz);
142	for (; rela < relalim; rela++) {
143		where = (Elf_Addr *)(relocbase + rela->r_offset);
144		*where = (Elf_Addr)(relocbase + rela->r_addend);
145	}
146}
147
148int
149_rtld_relocate_nonplt_objects(Obj_Entry *obj)
150{
151	const Elf_Rela *rela;
152
153	for (rela = obj->rela; rela < obj->relalim; rela++) {
154		Elf_Addr        *where;
155		const Elf_Sym   *def;
156		const Obj_Entry *defobj;
157		Elf_Addr         tmp;
158		unsigned long	 symnum;
159
160		where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
161		symnum = ELF_R_SYM(rela->r_info);
162
163		switch (ELF_R_TYPE(rela->r_info)) {
164#if 1 /* XXX Should not be necessary. */
165		case R_TYPE(JMP_SLOT):
166#endif
167		case R_TYPE(NONE):
168			break;
169
170		case R_TYPE(32):	/* word32 S + A */
171		case R_TYPE(GLOB_DAT):	/* word32 S + A */
172			def = _rtld_find_symdef(symnum, obj, &defobj, false);
173			if (def == NULL)
174				return -1;
175
176			tmp = (Elf_Addr)(defobj->relocbase + def->st_value +
177			    rela->r_addend);
178			if (*where != tmp)
179				*where = tmp;
180			rdbg(("32/GLOB_DAT %s in %s --> %p in %s",
181			    obj->strtab + obj->symtab[symnum].st_name,
182			    obj->path, (void *)*where, defobj->path));
183			break;
184
185		case R_TYPE(RELATIVE):	/* word32 B + A */
186			*where = (Elf_Addr)(obj->relocbase + rela->r_addend);
187			rdbg(("RELATIVE in %s --> %p", obj->path,
188			    (void *)*where));
189			break;
190
191		case R_TYPE(COPY):
192			/*
193			 * These are deferred until all other relocations have
194			 * been done.  All we do here is make sure that the
195			 * COPY relocation is not in a shared library.  They
196			 * are allowed only in executable files.
197			 */
198			if (obj->isdynamic) {
199				_rtld_error(
200			"%s: Unexpected R_COPY relocation in shared library",
201				    obj->path);
202				return -1;
203			}
204			rdbg(("COPY (avoid in main)"));
205			break;
206
207		case R_TYPE(DTPMOD32):
208			def = _rtld_find_symdef(symnum, obj, &defobj, false);
209			if (def == NULL)
210				return -1;
211
212			*where = (Elf_Addr)defobj->tlsindex;
213			rdbg(("DTPMOD32 %s in %s --> %p in %s",
214			    obj->strtab + obj->symtab[symnum].st_name,
215			    obj->path, (void *)*where, defobj->path));
216			break;
217
218		case R_TYPE(DTPREL32):
219			def = _rtld_find_symdef(symnum, obj, &defobj, false);
220			if (def == NULL)
221				return -1;
222
223			if (!defobj->tls_done && _rtld_tls_offset_allocate(obj))
224				return -1;
225
226			*where = (Elf_Addr)(def->st_value + rela->r_addend
227			    - TLS_DTV_OFFSET);
228			rdbg(("DTPREL32 %s in %s --> %p in %s",
229			    obj->strtab + obj->symtab[symnum].st_name,
230			    obj->path, (void *)*where, defobj->path));
231			break;
232
233		case R_TYPE(TPREL32):
234			def = _rtld_find_symdef(symnum, obj, &defobj, false);
235			if (def == NULL)
236				return -1;
237
238			if (!defobj->tls_done && _rtld_tls_offset_allocate(obj))
239				return -1;
240
241			*where = (Elf_Addr)(def->st_value + rela->r_addend
242			    + defobj->tlsoffset - TLS_TP_OFFSET);
243			rdbg(("TPREL32 %s in %s --> %p in %s",
244			    obj->strtab + obj->symtab[symnum].st_name,
245			    obj->path, (void *)*where, defobj->path));
246			break;
247
248		default:
249			rdbg(("sym = %lu, type = %lu, offset = %p, "
250			    "addend = %p, contents = %p, symbol = %s",
251			    symnum, (u_long)ELF_R_TYPE(rela->r_info),
252			    (void *)rela->r_offset, (void *)rela->r_addend,
253			    (void *)*where,
254			    obj->strtab + obj->symtab[symnum].st_name));
255			_rtld_error("%s: Unsupported relocation type %ld "
256			    "in non-PLT relocations",
257			    obj->path, (u_long) ELF_R_TYPE(rela->r_info));
258			return -1;
259		}
260	}
261	return 0;
262}
263
264int
265_rtld_relocate_plt_lazy(const Obj_Entry *obj)
266{
267	Elf_Addr * const pltresolve = obj->pltgot + 8;
268	const Elf_Rela *rela;
269	int reloff;
270
271	for (rela = obj->pltrela, reloff = 0;
272	     rela < obj->pltrelalim;
273	     rela++, reloff++) {
274		Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset);
275
276		assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT));
277
278		if (obj->gotptr != NULL) {
279			/*
280			 * For now, simply treat then as relative.
281			 */
282			*where += (Elf_Addr)obj->relocbase;
283		} else {
284			int distance;
285
286			if (reloff < 32768) {
287				/* li	r11,reloff */
288				*where++ = 0x39600000 | reloff;
289			} else {
290				/* lis  r11,ha(reloff) */
291				/* addi	r11,l(reloff) */
292				*where++ = 0x3d600000 | ha(reloff);
293				*where++ = 0x396b0000 | l(reloff);
294			}
295			/* b	pltresolve */
296			distance = (Elf_Addr)pltresolve - (Elf_Addr)where;
297			*where++ = 0x48000000 | (distance & 0x03fffffc);
298
299			/*
300			 * Icache invalidation is not done for each entry here
301			 * because we sync the entire code part of the PLT once
302			 * in _rtld_setup_pltgot() after all the entries have been
303			 * initialized.
304			 */
305			/* __syncicache(where - 3, 12); */
306		}
307	}
308
309	return 0;
310}
311
312static int
313_rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, int reloff, Elf_Addr *tp)
314{
315	Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset);
316	Elf_Addr value;
317	const Elf_Sym *def;
318	const Obj_Entry *defobj;
319	int distance;
320	unsigned long info = rela->r_info;
321
322	assert(ELF_R_TYPE(info) == R_TYPE(JMP_SLOT));
323
324	def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL);
325	if (__predict_false(def == NULL))
326		return -1;
327	if (__predict_false(def == &_rtld_sym_zero))
328		return 0;
329
330	value = (Elf_Addr)(defobj->relocbase + def->st_value);
331	distance = value - (Elf_Addr)where;
332	rdbg(("bind now/fixup in %s --> new=%p",
333	    defobj->strtab + def->st_name, (void *)value));
334
335	if (obj->gotptr != NULL) {
336		/*
337		 * For Secure-PLT we simply replace the entry in GOT with the address
338		 * of the routine.
339		 */
340		assert(where >= (Elf_Word *)obj->pltgot);
341		assert(where < (Elf_Word *)obj->pltgot + (obj->pltrelalim - obj->pltrela));
342		*where = value;
343	} else if (abs(distance) < 32*1024*1024) {	/* inside 32MB? */
344		/* b	value	# branch directly */
345		*where = 0x48000000 | (distance & 0x03fffffc);
346		__syncicache(where, 4);
347	} else {
348		Elf_Addr *pltcall, *jmptab;
349		int N = obj->pltrelalim - obj->pltrela;
350
351		/* Entries beyond 8192 take twice as much space. */
352		if (N > 8192)
353			N += N-8192;
354
355		pltcall = obj->pltgot;
356		jmptab = pltcall + 18 + N * 2;
357
358		jmptab[reloff] = value;
359
360		if (reloff < 32768) {
361			/* li	r11,reloff */
362			*where++ = 0x39600000 | reloff;
363		} else {
364#ifdef notyet
365			/* lis  r11,ha(value) */
366			/* addi	r11,l(value) */
367			/* mtctr r11 */
368			/* bctr */
369			*where++ = 0x3d600000 | ha(value);
370			*where++ = 0x396b0000 | l(value);
371			*where++ = 0x7d6903a6;
372			*where++ = 0x4e800420;
373#else
374			/* lis  r11,ha(reloff) */
375			/* addi	r11,l(reloff) */
376			*where++ = 0x3d600000 | ha(reloff);
377			*where++ = 0x396b0000 | l(reloff);
378#endif
379		}
380		/* b	pltcall	*/
381		distance = (Elf_Addr)pltcall - (Elf_Addr)where;
382		*where++ = 0x48000000 | (distance & 0x03fffffc);
383		__syncicache(where - 3, 12);
384	}
385
386	if (tp)
387		*tp = value;
388	return 0;
389}
390
391caddr_t
392_rtld_bind(const Obj_Entry *obj, Elf_Word reloff)
393{
394	const Elf_Rela *rela = obj->pltrela + reloff;
395	Elf_Addr new_value;
396	int err;
397
398	new_value = 0;	/* XXX gcc */
399
400	_rtld_shared_enter();
401	err = _rtld_relocate_plt_object(obj, rela, reloff, &new_value);
402	if (err)
403		_rtld_die();
404	_rtld_shared_exit();
405
406	return (caddr_t)new_value;
407}
408
409int
410_rtld_relocate_plt_objects(const Obj_Entry *obj)
411{
412	const Elf_Rela *rela;
413	int reloff;
414
415	for (rela = obj->pltrela, reloff = 0; rela < obj->pltrelalim; rela++, reloff++) {
416		if (_rtld_relocate_plt_object(obj, rela, reloff, NULL) < 0)
417			return -1;
418	}
419	return 0;
420}
421