1/*-
2 * Copyright (c) 2015-2017 Ruslan Bukin <br@bsdpad.com>
3 * All rights reserved.
4 *
5 * This software was developed by SRI International and the University of
6 * Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237
7 * ("CTSRD"), as part of the DARPA CRASH research programme.
8 *
9 * This software was developed by the University of Cambridge Computer
10 * Laboratory as part of the CTSRD Project, with support from the UK Higher
11 * Education Innovation Fund (HEIF).
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 *    notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 *    notice, this list of conditions and the following disclaimer in the
20 *    documentation and/or other materials provided with the distribution.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD$");
37
38#include <sys/types.h>
39
40#include <stdlib.h>
41
42#include "debug.h"
43#include "rtld.h"
44#include "rtld_printf.h"
45
46/*
47 * It is possible for the compiler to emit relocations for unaligned data.
48 * We handle this situation with these inlines.
49 */
50#define	RELOC_ALIGNED_P(x) \
51	(((uintptr_t)(x) & (sizeof(void *) - 1)) == 0)
52
53uint64_t
54set_gp(Obj_Entry *obj)
55{
56	uint64_t old;
57	SymLook req;
58	uint64_t gp;
59	int res;
60
61	__asm __volatile("mv    %0, gp" : "=r"(old));
62
63	symlook_init(&req, "__global_pointer$");
64	req.ventry = NULL;
65	req.flags = SYMLOOK_EARLY;
66	res = symlook_obj(&req, obj);
67
68	if (res == 0) {
69		gp = req.sym_out->st_value;
70		__asm __volatile("mv    gp, %0" :: "r"(gp));
71	}
72
73	return (old);
74}
75
76void
77init_pltgot(Obj_Entry *obj)
78{
79
80	if (obj->pltgot != NULL) {
81		obj->pltgot[0] = (Elf_Addr)&_rtld_bind_start;
82		obj->pltgot[1] = (Elf_Addr)obj;
83	}
84}
85
86int
87do_copy_relocations(Obj_Entry *dstobj)
88{
89	const Obj_Entry *srcobj, *defobj;
90	const Elf_Rela *relalim;
91	const Elf_Rela *rela;
92	const Elf_Sym *srcsym;
93	const Elf_Sym *dstsym;
94	const void *srcaddr;
95	const char *name;
96	void *dstaddr;
97	SymLook req;
98	size_t size;
99	int res;
100
101	/*
102	 * COPY relocs are invalid outside of the main program
103	 */
104	assert(dstobj->mainprog);
105
106	relalim = (const Elf_Rela *)((const char *)dstobj->rela +
107	    dstobj->relasize);
108	for (rela = dstobj->rela; rela < relalim; rela++) {
109		if (ELF_R_TYPE(rela->r_info) != R_RISCV_COPY)
110			continue;
111
112		dstaddr = (void *)(dstobj->relocbase + rela->r_offset);
113		dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info);
114		name = dstobj->strtab + dstsym->st_name;
115		size = dstsym->st_size;
116
117		symlook_init(&req, name);
118		req.ventry = fetch_ventry(dstobj, ELF_R_SYM(rela->r_info));
119		req.flags = SYMLOOK_EARLY;
120
121		for (srcobj = globallist_next(dstobj); srcobj != NULL;
122		     srcobj = globallist_next(srcobj)) {
123			res = symlook_obj(&req, srcobj);
124			if (res == 0) {
125				srcsym = req.sym_out;
126				defobj = req.defobj_out;
127				break;
128			}
129		}
130		if (srcobj == NULL) {
131			_rtld_error(
132"Undefined symbol \"%s\" referenced from COPY relocation in %s",
133			    name, dstobj->path);
134			return (-1);
135		}
136
137		srcaddr = (const void *)(defobj->relocbase + srcsym->st_value);
138		memcpy(dstaddr, srcaddr, size);
139	}
140
141	return (0);
142}
143
144/*
145 * Process the PLT relocations.
146 */
147int
148reloc_plt(Obj_Entry *obj, int flags __unused, RtldLockState *lockstate __unused)
149{
150	const Elf_Rela *relalim;
151	const Elf_Rela *rela;
152
153	relalim = (const Elf_Rela *)((const char *)obj->pltrela +
154	    obj->pltrelasize);
155	for (rela = obj->pltrela; rela < relalim; rela++) {
156		Elf_Addr *where;
157
158		assert(ELF_R_TYPE(rela->r_info) == R_RISCV_JUMP_SLOT);
159
160		where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
161		*where += (Elf_Addr)obj->relocbase;
162	}
163
164	return (0);
165}
166
167/*
168 * LD_BIND_NOW was set - force relocation for all jump slots
169 */
170int
171reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate)
172{
173	const Obj_Entry *defobj;
174	const Elf_Rela *relalim;
175	const Elf_Rela *rela;
176	const Elf_Sym *def;
177
178	relalim = (const Elf_Rela *)((const char *)obj->pltrela +
179	    obj->pltrelasize);
180	for (rela = obj->pltrela; rela < relalim; rela++) {
181		Elf_Addr *where;
182
183		where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
184		switch(ELF_R_TYPE(rela->r_info)) {
185		case R_RISCV_JUMP_SLOT:
186			def = find_symdef(ELF_R_SYM(rela->r_info), obj,
187			    &defobj, SYMLOOK_IN_PLT | flags, NULL, lockstate);
188			if (def == NULL) {
189				dbg("reloc_jmpslots: sym not found");
190				return (-1);
191			}
192
193			*where = (Elf_Addr)(defobj->relocbase + def->st_value);
194			break;
195		default:
196			_rtld_error("Unknown relocation type %x in jmpslot",
197			    (unsigned int)ELF_R_TYPE(rela->r_info));
198			return (-1);
199		}
200	}
201
202	return (0);
203}
204
205int
206reloc_iresolve(Obj_Entry *obj __unused,
207    struct Struct_RtldLockState *lockstate __unused)
208{
209
210	/* XXX not implemented */
211	return (0);
212}
213
214int
215reloc_iresolve_nonplt(Obj_Entry *obj __unused,
216    struct Struct_RtldLockState *lockstate __unused)
217{
218
219	/* XXX not implemented */
220	return (0);
221}
222
223int
224reloc_gnu_ifunc(Obj_Entry *obj __unused, int flags __unused,
225   struct Struct_RtldLockState *lockstate __unused)
226{
227
228	/* XXX not implemented */
229	return (0);
230}
231
232Elf_Addr
233reloc_jmpslot(Elf_Addr *where, Elf_Addr target,
234    const Obj_Entry *defobj __unused, const Obj_Entry *obj __unused,
235    const Elf_Rel *rel)
236{
237
238	assert(ELF_R_TYPE(rel->r_info) == R_RISCV_JUMP_SLOT);
239
240	if (*where != target && !ld_bind_not)
241		*where = target;
242	return (target);
243}
244
245/*
246 * Process non-PLT relocations
247 */
248int
249reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags,
250    RtldLockState *lockstate)
251{
252	const Obj_Entry *defobj;
253	const Elf_Rela *relalim;
254	const Elf_Rela *rela;
255	const Elf_Sym *def;
256	SymCache *cache;
257	Elf_Addr *where;
258	unsigned long symnum;
259
260	if ((flags & SYMLOOK_IFUNC) != 0)
261		/* XXX not implemented */
262		return (0);
263
264	/*
265	 * The dynamic loader may be called from a thread, we have
266	 * limited amounts of stack available so we cannot use alloca().
267	 */
268	if (obj == obj_rtld)
269		cache = NULL;
270	else
271		cache = calloc(obj->dynsymcount, sizeof(SymCache));
272		/* No need to check for NULL here */
273
274	relalim = (const Elf_Rela *)((const char *)obj->rela + obj->relasize);
275	for (rela = obj->rela; rela < relalim; rela++) {
276		where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
277		symnum = ELF_R_SYM(rela->r_info);
278
279		switch (ELF_R_TYPE(rela->r_info)) {
280		case R_RISCV_JUMP_SLOT:
281			/* This will be handled by the plt/jmpslot routines */
282			break;
283		case R_RISCV_NONE:
284			break;
285		case R_RISCV_64:
286			def = find_symdef(symnum, obj, &defobj, flags, cache,
287			    lockstate);
288			if (def == NULL)
289				return (-1);
290
291			*where = (Elf_Addr)(defobj->relocbase + def->st_value +
292			    rela->r_addend);
293			break;
294		case R_RISCV_TLS_DTPMOD64:
295			def = find_symdef(symnum, obj, &defobj, flags, cache,
296			    lockstate);
297			if (def == NULL)
298				return -1;
299
300			*where += (Elf_Addr)defobj->tlsindex;
301			break;
302		case R_RISCV_COPY:
303			/*
304			 * These are deferred until all other relocations have
305			 * been done. All we do here is make sure that the
306			 * COPY relocation is not in a shared library. They
307			 * are allowed only in executable files.
308			 */
309			if (!obj->mainprog) {
310				_rtld_error("%s: Unexpected R_RISCV_COPY "
311				    "relocation in shared library", obj->path);
312				return (-1);
313			}
314			break;
315		case R_RISCV_TLS_DTPREL64:
316			def = find_symdef(symnum, obj, &defobj, flags, cache,
317			    lockstate);
318			if (def == NULL)
319				return (-1);
320			/*
321			 * We lazily allocate offsets for static TLS as we
322			 * see the first relocation that references the
323			 * TLS block. This allows us to support (small
324			 * amounts of) static TLS in dynamically loaded
325			 * modules. If we run out of space, we generate an
326			 * error.
327			 */
328			if (!defobj->tls_done) {
329				if (!allocate_tls_offset(
330				    __DECONST(Obj_Entry *, defobj))) {
331					_rtld_error(
332					    "%s: No space available for static "
333					    "Thread Local Storage", obj->path);
334					return (-1);
335				}
336			}
337
338			*where += (Elf_Addr)(def->st_value + rela->r_addend
339			    - TLS_DTV_OFFSET);
340			break;
341		case R_RISCV_TLS_TPREL64:
342			def = find_symdef(symnum, obj, &defobj, flags, cache,
343			    lockstate);
344			if (def == NULL)
345				return (-1);
346
347			/*
348			 * We lazily allocate offsets for static TLS as we
349			 * see the first relocation that references the
350			 * TLS block. This allows us to support (small
351			 * amounts of) static TLS in dynamically loaded
352			 * modules. If we run out of space, we generate an
353			 * error.
354			 */
355			if (!defobj->tls_done) {
356				if (!allocate_tls_offset(
357				    __DECONST(Obj_Entry *, defobj))) {
358					_rtld_error(
359					    "%s: No space available for static "
360					    "Thread Local Storage", obj->path);
361					return (-1);
362				}
363			}
364
365			*where = (def->st_value + rela->r_addend +
366			    defobj->tlsoffset - TLS_TP_OFFSET - TLS_TCB_SIZE);
367			break;
368		case R_RISCV_RELATIVE:
369			*where = (Elf_Addr)(obj->relocbase + rela->r_addend);
370			break;
371		default:
372			rtld_printf("%s: Unhandled relocation %lu\n",
373			    obj->path, ELF_R_TYPE(rela->r_info));
374			return (-1);
375		}
376	}
377
378	return (0);
379}
380
381void
382ifunc_init(Elf_Auxinfo aux_info[__min_size(AT_COUNT)] __unused)
383{
384
385}
386
387void
388allocate_initial_tls(Obj_Entry *objs)
389{
390	Elf_Addr **tp;
391
392	/*
393	 * Fix the size of the static TLS block by using the maximum
394	 * offset allocated so far and adding a bit for dynamic modules to
395	 * use.
396	 */
397	tls_static_space = tls_last_offset + tls_last_size +
398	    RTLD_STATIC_TLS_EXTRA;
399
400	tp = (Elf_Addr **)((char *)allocate_tls(objs, NULL, TLS_TCB_SIZE, 16)
401	    + TLS_TP_OFFSET + TLS_TCB_SIZE);
402
403	__asm __volatile("mv  tp, %0" :: "r"(tp));
404}
405
406void *
407__tls_get_addr(tls_index* ti)
408{
409	char *_tp;
410	void *p;
411
412	__asm __volatile("mv %0, tp" : "=r" (_tp));
413
414	p = tls_get_addr_common((Elf_Addr**)((Elf_Addr)_tp - TLS_TP_OFFSET
415	    - TLS_TCB_SIZE), ti->ti_module, ti->ti_offset);
416
417	return ((char*)p + TLS_DTV_OFFSET);
418}
419