xref: /freebsd/sys/kern/link_elf.c (revision d65cd7a57bf0600b722afc770838a5d0c1c3a8e1)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 1998-2000 Doug Rabson
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include "opt_ddb.h"
33 #include "opt_gdb.h"
34 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #ifdef GPROF
38 #include <sys/gmon.h>
39 #endif
40 #include <sys/kernel.h>
41 #include <sys/lock.h>
42 #include <sys/malloc.h>
43 #ifdef SPARSE_MAPPING
44 #include <sys/mman.h>
45 #endif
46 #include <sys/mutex.h>
47 #include <sys/mount.h>
48 #include <sys/pcpu.h>
49 #include <sys/proc.h>
50 #include <sys/namei.h>
51 #include <sys/fcntl.h>
52 #include <sys/vnode.h>
53 #include <sys/linker.h>
54 #include <sys/sysctl.h>
55 
56 #include <machine/elf.h>
57 
58 #include <net/vnet.h>
59 
60 #include <security/mac/mac_framework.h>
61 
62 #include <vm/vm.h>
63 #include <vm/vm_param.h>
64 #ifdef SPARSE_MAPPING
65 #include <vm/vm_object.h>
66 #include <vm/vm_kern.h>
67 #include <vm/vm_extern.h>
68 #endif
69 #include <vm/pmap.h>
70 #include <vm/vm_map.h>
71 
72 #include <sys/link_elf.h>
73 
74 #include "linker_if.h"
75 
76 #define MAXSEGS 4
77 
78 typedef struct elf_file {
79 	struct linker_file lf;		/* Common fields */
80 	int		preloaded;	/* Was file pre-loaded */
81 	caddr_t		address;	/* Relocation address */
82 #ifdef SPARSE_MAPPING
83 	vm_object_t	object;		/* VM object to hold file pages */
84 #endif
85 	Elf_Dyn		*dynamic;	/* Symbol table etc. */
86 	Elf_Hashelt	nbuckets;	/* DT_HASH info */
87 	Elf_Hashelt	nchains;
88 	const Elf_Hashelt *buckets;
89 	const Elf_Hashelt *chains;
90 	caddr_t		hash;
91 	caddr_t		strtab;		/* DT_STRTAB */
92 	int		strsz;		/* DT_STRSZ */
93 	const Elf_Sym	*symtab;		/* DT_SYMTAB */
94 	Elf_Addr	*got;		/* DT_PLTGOT */
95 	const Elf_Rel	*pltrel;	/* DT_JMPREL */
96 	int		pltrelsize;	/* DT_PLTRELSZ */
97 	const Elf_Rela	*pltrela;	/* DT_JMPREL */
98 	int		pltrelasize;	/* DT_PLTRELSZ */
99 	const Elf_Rel	*rel;		/* DT_REL */
100 	int		relsize;	/* DT_RELSZ */
101 	const Elf_Rela	*rela;		/* DT_RELA */
102 	int		relasize;	/* DT_RELASZ */
103 	caddr_t		modptr;
104 	const Elf_Sym	*ddbsymtab;	/* The symbol table we are using */
105 	long		ddbsymcnt;	/* Number of symbols */
106 	caddr_t		ddbstrtab;	/* String table */
107 	long		ddbstrcnt;	/* number of bytes in string table */
108 	caddr_t		symbase;	/* malloc'ed symbold base */
109 	caddr_t		strbase;	/* malloc'ed string base */
110 	caddr_t		ctftab;		/* CTF table */
111 	long		ctfcnt;		/* number of bytes in CTF table */
112 	caddr_t		ctfoff;		/* CTF offset table */
113 	caddr_t		typoff;		/* Type offset table */
114 	long		typlen;		/* Number of type entries. */
115 	Elf_Addr	pcpu_start;	/* Pre-relocation pcpu set start. */
116 	Elf_Addr	pcpu_stop;	/* Pre-relocation pcpu set stop. */
117 	Elf_Addr	pcpu_base;	/* Relocated pcpu set address. */
118 #ifdef VIMAGE
119 	Elf_Addr	vnet_start;	/* Pre-relocation vnet set start. */
120 	Elf_Addr	vnet_stop;	/* Pre-relocation vnet set stop. */
121 	Elf_Addr	vnet_base;	/* Relocated vnet set address. */
122 #endif
123 #ifdef GDB
124 	struct link_map	gdb;		/* hooks for gdb */
125 #endif
126 } *elf_file_t;
127 
128 struct elf_set {
129 	Elf_Addr	es_start;
130 	Elf_Addr	es_stop;
131 	Elf_Addr	es_base;
132 	TAILQ_ENTRY(elf_set)	es_link;
133 };
134 
135 TAILQ_HEAD(elf_set_head, elf_set);
136 
137 #include <kern/kern_ctf.c>
138 
139 static int	link_elf_link_common_finish(linker_file_t);
140 static int	link_elf_link_preload(linker_class_t cls,
141 				      const char *, linker_file_t *);
142 static int	link_elf_link_preload_finish(linker_file_t);
143 static int	link_elf_load_file(linker_class_t, const char *,
144 		    linker_file_t *);
145 static int	link_elf_lookup_symbol(linker_file_t, const char *,
146 		    c_linker_sym_t *);
147 static int	link_elf_symbol_values(linker_file_t, c_linker_sym_t,
148 		    linker_symval_t *);
149 static int	link_elf_search_symbol(linker_file_t, caddr_t,
150 		    c_linker_sym_t *, long *);
151 
152 static void	link_elf_unload_file(linker_file_t);
153 static void	link_elf_unload_preload(linker_file_t);
154 static int	link_elf_lookup_set(linker_file_t, const char *,
155 		    void ***, void ***, int *);
156 static int	link_elf_each_function_name(linker_file_t,
157 		    int (*)(const char *, void *), void *);
158 static int	link_elf_each_function_nameval(linker_file_t,
159 		    linker_function_nameval_callback_t, void *);
160 static void	link_elf_reloc_local(linker_file_t);
161 static long	link_elf_symtab_get(linker_file_t, const Elf_Sym **);
162 static long	link_elf_strtab_get(linker_file_t, caddr_t *);
163 static int	elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
164 
165 static kobj_method_t link_elf_methods[] = {
166 	KOBJMETHOD(linker_lookup_symbol,	link_elf_lookup_symbol),
167 	KOBJMETHOD(linker_symbol_values,	link_elf_symbol_values),
168 	KOBJMETHOD(linker_search_symbol,	link_elf_search_symbol),
169 	KOBJMETHOD(linker_unload,		link_elf_unload_file),
170 	KOBJMETHOD(linker_load_file,		link_elf_load_file),
171 	KOBJMETHOD(linker_link_preload,		link_elf_link_preload),
172 	KOBJMETHOD(linker_link_preload_finish,	link_elf_link_preload_finish),
173 	KOBJMETHOD(linker_lookup_set,		link_elf_lookup_set),
174 	KOBJMETHOD(linker_each_function_name,	link_elf_each_function_name),
175 	KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
176 	KOBJMETHOD(linker_ctf_get,		link_elf_ctf_get),
177 	KOBJMETHOD(linker_symtab_get,		link_elf_symtab_get),
178 	KOBJMETHOD(linker_strtab_get,		link_elf_strtab_get),
179 	KOBJMETHOD_END
180 };
181 
182 static struct linker_class link_elf_class = {
183 #if ELF_TARG_CLASS == ELFCLASS32
184 	"elf32",
185 #else
186 	"elf64",
187 #endif
188 	link_elf_methods, sizeof(struct elf_file)
189 };
190 
191 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase,
192     const void *data, int type, elf_lookup_fn lookup);
193 
194 static int	parse_dynamic(elf_file_t);
195 static int	relocate_file(elf_file_t);
196 static int	relocate_file1(elf_file_t ef, elf_lookup_fn lookup,
197 		    elf_reloc_fn reloc, bool ifuncs);
198 static int	link_elf_preload_parse_symbols(elf_file_t);
199 
200 static struct elf_set_head set_pcpu_list;
201 #ifdef VIMAGE
202 static struct elf_set_head set_vnet_list;
203 #endif
204 
205 static void
206 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
207 {
208 	struct elf_set *set, *iter;
209 
210 	set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
211 	set->es_start = start;
212 	set->es_stop = stop;
213 	set->es_base = base;
214 
215 	TAILQ_FOREACH(iter, list, es_link) {
216 
217 		KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
218 		    (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
219 		    ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
220 		    (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
221 		    (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
222 
223 		if (iter->es_start > set->es_start) {
224 			TAILQ_INSERT_BEFORE(iter, set, es_link);
225 			break;
226 		}
227 	}
228 
229 	if (iter == NULL)
230 		TAILQ_INSERT_TAIL(list, set, es_link);
231 }
232 
233 static int
234 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
235 {
236 	struct elf_set *set;
237 
238 	TAILQ_FOREACH(set, list, es_link) {
239 		if (addr < set->es_start)
240 			return (0);
241 		if (addr < set->es_stop) {
242 			*start = set->es_start;
243 			*base = set->es_base;
244 			return (1);
245 		}
246 	}
247 
248 	return (0);
249 }
250 
251 static void
252 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
253 {
254 	struct elf_set *set;
255 
256 	TAILQ_FOREACH(set, list, es_link) {
257 		if (start < set->es_start)
258 			break;
259 		if (start == set->es_start) {
260 			TAILQ_REMOVE(list, set, es_link);
261 			free(set, M_LINKER);
262 			return;
263 		}
264 	}
265 	KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
266 	    (uintmax_t)start));
267 }
268 
269 #ifdef GDB
270 static void	r_debug_state(struct r_debug *, struct link_map *);
271 
272 /*
273  * A list of loaded modules for GDB to use for loading symbols.
274  */
275 struct r_debug r_debug;
276 
277 #define GDB_STATE(s) do {				\
278 	r_debug.r_state = s; r_debug_state(NULL, NULL);	\
279 } while (0)
280 
281 /*
282  * Function for the debugger to set a breakpoint on to gain control.
283  */
284 static void
285 r_debug_state(struct r_debug *dummy_one __unused,
286 	      struct link_map *dummy_two __unused)
287 {
288 }
289 
290 static void
291 link_elf_add_gdb(struct link_map *l)
292 {
293 	struct link_map *prev;
294 
295 	l->l_next = NULL;
296 
297 	if (r_debug.r_map == NULL) {
298 		/* Add first. */
299 		l->l_prev = NULL;
300 		r_debug.r_map = l;
301 	} else {
302 		/* Append to list. */
303 		for (prev = r_debug.r_map;
304 		    prev->l_next != NULL;
305 		    prev = prev->l_next)
306 			;
307 		l->l_prev = prev;
308 		prev->l_next = l;
309 	}
310 }
311 
312 static void
313 link_elf_delete_gdb(struct link_map *l)
314 {
315 	if (l->l_prev == NULL) {
316 		/* Remove first. */
317 		if ((r_debug.r_map = l->l_next) != NULL)
318 			l->l_next->l_prev = NULL;
319 	} else {
320 		/* Remove any but first. */
321 		if ((l->l_prev->l_next = l->l_next) != NULL)
322 			l->l_next->l_prev = l->l_prev;
323 	}
324 }
325 #endif /* GDB */
326 
327 /*
328  * The kernel symbol table starts here.
329  */
330 extern struct _dynamic _DYNAMIC;
331 
332 static void
333 link_elf_error(const char *filename, const char *s)
334 {
335 	if (filename == NULL)
336 		printf("kldload: %s\n", s);
337 	else
338 		printf("kldload: %s: %s\n", filename, s);
339 }
340 
341 static void
342 link_elf_invoke_ctors(caddr_t addr, size_t size)
343 {
344 	void (**ctor)(void);
345 	size_t i, cnt;
346 
347 	if (addr == NULL || size == 0)
348 		return;
349 	cnt = size / sizeof(*ctor);
350 	ctor = (void *)addr;
351 	for (i = 0; i < cnt; i++) {
352 		if (ctor[i] != NULL)
353 			(*ctor[i])();
354 	}
355 }
356 
357 /*
358  * Actions performed after linking/loading both the preloaded kernel and any
359  * modules; whether preloaded or dynamicly loaded.
360  */
361 static int
362 link_elf_link_common_finish(linker_file_t lf)
363 {
364 #ifdef GDB
365 	elf_file_t ef = (elf_file_t)lf;
366 	char *newfilename;
367 #endif
368 	int error;
369 
370 	/* Notify MD code that a module is being loaded. */
371 	error = elf_cpu_load_file(lf);
372 	if (error != 0)
373 		return (error);
374 
375 #ifdef GDB
376 	GDB_STATE(RT_ADD);
377 	ef->gdb.l_addr = lf->address;
378 	newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
379 	strcpy(newfilename, lf->filename);
380 	ef->gdb.l_name = newfilename;
381 	ef->gdb.l_ld = ef->dynamic;
382 	link_elf_add_gdb(&ef->gdb);
383 	GDB_STATE(RT_CONSISTENT);
384 #endif
385 
386 	/* Invoke .ctors */
387 	link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
388 	return (0);
389 }
390 
391 #ifdef RELOCATABLE_KERNEL
392 extern vm_offset_t __startkernel, __endkernel;
393 #endif
394 
395 static unsigned long kern_relbase = KERNBASE;
396 
397 SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD,
398 	SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address");
399 SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD,
400 	&kern_relbase, 0, "Kernel relocated base address");
401 
402 static void
403 link_elf_init(void* arg)
404 {
405 	Elf_Dyn *dp;
406 	Elf_Addr *ctors_addrp;
407 	Elf_Size *ctors_sizep;
408 	caddr_t modptr, baseptr, sizeptr;
409 	elf_file_t ef;
410 	const char *modname;
411 
412 	linker_add_class(&link_elf_class);
413 
414 	dp = (Elf_Dyn *)&_DYNAMIC;
415 	modname = NULL;
416 	modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
417 	if (modptr == NULL)
418 		modptr = preload_search_by_type("elf kernel");
419 	modname = (char *)preload_search_info(modptr, MODINFO_NAME);
420 	if (modname == NULL)
421 		modname = "kernel";
422 	linker_kernel_file = linker_make_file(modname, &link_elf_class);
423 	if (linker_kernel_file == NULL)
424 		panic("%s: Can't create linker structures for kernel",
425 		    __func__);
426 
427 	ef = (elf_file_t) linker_kernel_file;
428 	ef->preloaded = 1;
429 #ifdef RELOCATABLE_KERNEL
430 	ef->address = (caddr_t) (__startkernel - KERNBASE);
431 #else
432 	ef->address = 0;
433 #endif
434 #ifdef SPARSE_MAPPING
435 	ef->object = NULL;
436 #endif
437 	ef->dynamic = dp;
438 
439 	if (dp != NULL)
440 		parse_dynamic(ef);
441 #ifdef RELOCATABLE_KERNEL
442 	linker_kernel_file->address = (caddr_t)__startkernel;
443 	linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
444 	kern_relbase = (unsigned long)__startkernel;
445 #else
446 	linker_kernel_file->address += KERNBASE;
447 	linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
448 #endif
449 
450 	if (modptr != NULL) {
451 		ef->modptr = modptr;
452 		baseptr = preload_search_info(modptr, MODINFO_ADDR);
453 		if (baseptr != NULL)
454 			linker_kernel_file->address = *(caddr_t *)baseptr;
455 		sizeptr = preload_search_info(modptr, MODINFO_SIZE);
456 		if (sizeptr != NULL)
457 			linker_kernel_file->size = *(size_t *)sizeptr;
458 		ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
459 			MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
460 		ctors_sizep = (Elf_Size *)preload_search_info(modptr,
461 			MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
462 		if (ctors_addrp != NULL && ctors_sizep != NULL) {
463 			linker_kernel_file->ctors_addr = ef->address +
464 			    *ctors_addrp;
465 			linker_kernel_file->ctors_size = *ctors_sizep;
466 		}
467 	}
468 	(void)link_elf_preload_parse_symbols(ef);
469 
470 #ifdef GDB
471 	r_debug.r_map = NULL;
472 	r_debug.r_brk = r_debug_state;
473 	r_debug.r_state = RT_CONSISTENT;
474 #endif
475 
476 	(void)link_elf_link_common_finish(linker_kernel_file);
477 	linker_kernel_file->flags |= LINKER_FILE_LINKED;
478 	TAILQ_INIT(&set_pcpu_list);
479 #ifdef VIMAGE
480 	TAILQ_INIT(&set_vnet_list);
481 #endif
482 }
483 
484 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL);
485 
486 static int
487 link_elf_preload_parse_symbols(elf_file_t ef)
488 {
489 	caddr_t pointer;
490 	caddr_t ssym, esym, base;
491 	caddr_t strtab;
492 	int strcnt;
493 	Elf_Sym *symtab;
494 	int symcnt;
495 
496 	if (ef->modptr == NULL)
497 		return (0);
498 	pointer = preload_search_info(ef->modptr,
499 	    MODINFO_METADATA | MODINFOMD_SSYM);
500 	if (pointer == NULL)
501 		return (0);
502 	ssym = *(caddr_t *)pointer;
503 	pointer = preload_search_info(ef->modptr,
504 	    MODINFO_METADATA | MODINFOMD_ESYM);
505 	if (pointer == NULL)
506 		return (0);
507 	esym = *(caddr_t *)pointer;
508 
509 	base = ssym;
510 
511 	symcnt = *(long *)base;
512 	base += sizeof(long);
513 	symtab = (Elf_Sym *)base;
514 	base += roundup(symcnt, sizeof(long));
515 
516 	if (base > esym || base < ssym) {
517 		printf("Symbols are corrupt!\n");
518 		return (EINVAL);
519 	}
520 
521 	strcnt = *(long *)base;
522 	base += sizeof(long);
523 	strtab = base;
524 	base += roundup(strcnt, sizeof(long));
525 
526 	if (base > esym || base < ssym) {
527 		printf("Symbols are corrupt!\n");
528 		return (EINVAL);
529 	}
530 
531 	ef->ddbsymtab = symtab;
532 	ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
533 	ef->ddbstrtab = strtab;
534 	ef->ddbstrcnt = strcnt;
535 
536 	return (0);
537 }
538 
539 static int
540 parse_dynamic(elf_file_t ef)
541 {
542 	Elf_Dyn *dp;
543 	int plttype = DT_REL;
544 
545 	for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
546 		switch (dp->d_tag) {
547 		case DT_HASH:
548 		{
549 			/* From src/libexec/rtld-elf/rtld.c */
550 			const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
551 			    (ef->address + dp->d_un.d_ptr);
552 			ef->nbuckets = hashtab[0];
553 			ef->nchains = hashtab[1];
554 			ef->buckets = hashtab + 2;
555 			ef->chains = ef->buckets + ef->nbuckets;
556 			break;
557 		}
558 		case DT_STRTAB:
559 			ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
560 			break;
561 		case DT_STRSZ:
562 			ef->strsz = dp->d_un.d_val;
563 			break;
564 		case DT_SYMTAB:
565 			ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
566 			break;
567 		case DT_SYMENT:
568 			if (dp->d_un.d_val != sizeof(Elf_Sym))
569 				return (ENOEXEC);
570 			break;
571 		case DT_PLTGOT:
572 			ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
573 			break;
574 		case DT_REL:
575 			ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
576 			break;
577 		case DT_RELSZ:
578 			ef->relsize = dp->d_un.d_val;
579 			break;
580 		case DT_RELENT:
581 			if (dp->d_un.d_val != sizeof(Elf_Rel))
582 				return (ENOEXEC);
583 			break;
584 		case DT_JMPREL:
585 			ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
586 			break;
587 		case DT_PLTRELSZ:
588 			ef->pltrelsize = dp->d_un.d_val;
589 			break;
590 		case DT_RELA:
591 			ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
592 			break;
593 		case DT_RELASZ:
594 			ef->relasize = dp->d_un.d_val;
595 			break;
596 		case DT_RELAENT:
597 			if (dp->d_un.d_val != sizeof(Elf_Rela))
598 				return (ENOEXEC);
599 			break;
600 		case DT_PLTREL:
601 			plttype = dp->d_un.d_val;
602 			if (plttype != DT_REL && plttype != DT_RELA)
603 				return (ENOEXEC);
604 			break;
605 #ifdef GDB
606 		case DT_DEBUG:
607 			dp->d_un.d_ptr = (Elf_Addr)&r_debug;
608 			break;
609 #endif
610 		}
611 	}
612 
613 	if (plttype == DT_RELA) {
614 		ef->pltrela = (const Elf_Rela *)ef->pltrel;
615 		ef->pltrel = NULL;
616 		ef->pltrelasize = ef->pltrelsize;
617 		ef->pltrelsize = 0;
618 	}
619 
620 	ef->ddbsymtab = ef->symtab;
621 	ef->ddbsymcnt = ef->nchains;
622 	ef->ddbstrtab = ef->strtab;
623 	ef->ddbstrcnt = ef->strsz;
624 
625 	return elf_cpu_parse_dynamic(ef->address, ef->dynamic);
626 }
627 
628 #define	LS_PADDING	0x90909090
629 static int
630 parse_dpcpu(elf_file_t ef)
631 {
632 	int error, size;
633 #if defined(__i386__)
634 	uint32_t pad;
635 #endif
636 
637 	ef->pcpu_start = 0;
638 	ef->pcpu_stop = 0;
639 	error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
640 	    (void ***)&ef->pcpu_stop, NULL);
641 	/* Error just means there is no pcpu set to relocate. */
642 	if (error != 0)
643 		return (0);
644 	size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start;
645 	/* Empty set? */
646 	if (size < 1)
647 		return (0);
648 #if defined(__i386__)
649 	/* In case we do find __start/stop_set_ symbols double-check. */
650 	if (size < 4) {
651 		uprintf("Kernel module '%s' must be recompiled with "
652 		    "linker script\n", ef->lf.pathname);
653 		return (ENOEXEC);
654 	}
655 
656 	/* Padding from linker-script correct? */
657 	pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad));
658 	if (pad != LS_PADDING) {
659 		uprintf("Kernel module '%s' must be recompiled with "
660 		    "linker script, invalid padding %#04x (%#04x)\n",
661 		    ef->lf.pathname, pad, LS_PADDING);
662 		return (ENOEXEC);
663 	}
664 	/* If we only have valid padding, nothing to do. */
665 	if (size == 4)
666 		return (0);
667 #endif
668 	/*
669 	 * Allocate space in the primary pcpu area.  Copy in our
670 	 * initialization from the data section and then initialize
671 	 * all per-cpu storage from that.
672 	 */
673 	ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size);
674 	if (ef->pcpu_base == 0) {
675 		printf("%s: pcpu module space is out of space; "
676 		    "cannot allocate %d for %s\n",
677 		    __func__, size, ef->lf.pathname);
678 		return (ENOSPC);
679 	}
680 	memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size);
681 	dpcpu_copy((void *)ef->pcpu_base, size);
682 	elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
683 	    ef->pcpu_base);
684 
685 	return (0);
686 }
687 
688 #ifdef VIMAGE
689 static int
690 parse_vnet(elf_file_t ef)
691 {
692 	int error, size;
693 #if defined(__i386__)
694 	uint32_t pad;
695 #endif
696 
697 	ef->vnet_start = 0;
698 	ef->vnet_stop = 0;
699 	error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
700 	    (void ***)&ef->vnet_stop, NULL);
701 	/* Error just means there is no vnet data set to relocate. */
702 	if (error != 0)
703 		return (0);
704 	size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
705 	/* Empty set? */
706 	if (size < 1)
707 		return (0);
708 #if defined(__i386__)
709 	/* In case we do find __start/stop_set_ symbols double-check. */
710 	if (size < 4) {
711 		uprintf("Kernel module '%s' must be recompiled with "
712 		    "linker script\n", ef->lf.pathname);
713 		return (ENOEXEC);
714 	}
715 
716 	/* Padding from linker-script correct? */
717 	pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad));
718 	if (pad != LS_PADDING) {
719 		uprintf("Kernel module '%s' must be recompiled with "
720 		    "linker script, invalid padding %#04x (%#04x)\n",
721 		    ef->lf.pathname, pad, LS_PADDING);
722 		return (ENOEXEC);
723 	}
724 	/* If we only have valid padding, nothing to do. */
725 	if (size == 4)
726 		return (0);
727 #endif
728 	/*
729 	 * Allocate space in the primary vnet area.  Copy in our
730 	 * initialization from the data section and then initialize
731 	 * all per-vnet storage from that.
732 	 */
733 	ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size);
734 	if (ef->vnet_base == 0) {
735 		printf("%s: vnet module space is out of space; "
736 		    "cannot allocate %d for %s\n",
737 		    __func__, size, ef->lf.pathname);
738 		return (ENOSPC);
739 	}
740 	memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size);
741 	vnet_data_copy((void *)ef->vnet_base, size);
742 	elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
743 	    ef->vnet_base);
744 
745 	return (0);
746 }
747 #endif
748 #undef LS_PADDING
749 
750 /*
751  * Apply the specified protection to the loadable segments of a preloaded linker
752  * file.
753  */
754 static int
755 preload_protect(elf_file_t ef, vm_prot_t prot)
756 {
757 #ifdef __amd64__
758 	Elf_Ehdr *hdr;
759 	Elf_Phdr *phdr, *phlimit;
760 	vm_prot_t nprot;
761 	int error;
762 
763 	error = 0;
764 	hdr = (Elf_Ehdr *)ef->address;
765 	phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff);
766 	phlimit = phdr + hdr->e_phnum;
767 	for (; phdr < phlimit; phdr++) {
768 		if (phdr->p_type != PT_LOAD)
769 			continue;
770 
771 		nprot = prot | VM_PROT_READ;
772 		if ((phdr->p_flags & PF_W) != 0)
773 			nprot |= VM_PROT_WRITE;
774 		if ((phdr->p_flags & PF_X) != 0)
775 			nprot |= VM_PROT_EXECUTE;
776 		error = pmap_change_prot((vm_offset_t)ef->address +
777 		    phdr->p_vaddr, round_page(phdr->p_memsz), nprot);
778 		if (error != 0)
779 			break;
780 	}
781 	return (error);
782 #else
783 	return (0);
784 #endif
785 }
786 
787 #ifdef __arm__
788 /*
789  * Locate the ARM exception/unwind table info for DDB and stack(9) use by
790  * searching for the section header that describes it.  There may be no unwind
791  * info, for example in a module containing only data.
792  */
793 static void
794 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr)
795 {
796 	int i;
797 
798 	for (i = 0; i < nhdr; i++) {
799 		if (shdr[i].sh_type == SHT_ARM_EXIDX) {
800 			lf->exidx_addr = shdr[i].sh_addr + lf->address;
801 			lf->exidx_size = shdr[i].sh_size;
802 			break;
803 		}
804 	}
805 }
806 
807 /*
808  * Locate the section headers metadata in a preloaded module, then use it to
809  * locate the exception/unwind table in the module.  The size of the metadata
810  * block is stored in a uint32 word immediately before the data itself, and a
811  * comment in preload_search_info() says it is safe to rely on that.
812  */
813 static void
814 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr)
815 {
816 	uint32_t *modinfo;
817 	Elf_Shdr *shdr;
818 	uint32_t  nhdr;
819 
820 	modinfo = (uint32_t *)preload_search_info(modptr,
821 	    MODINFO_METADATA | MODINFOMD_SHDR);
822 	if (modinfo != NULL) {
823 		shdr = (Elf_Shdr *)modinfo;
824 		nhdr = modinfo[-1] / sizeof(Elf_Shdr);
825 		link_elf_locate_exidx(lf, shdr, nhdr);
826 	}
827 }
828 
829 #endif /* __arm__ */
830 
831 static int
832 link_elf_link_preload(linker_class_t cls, const char *filename,
833     linker_file_t *result)
834 {
835 	Elf_Addr *ctors_addrp;
836 	Elf_Size *ctors_sizep;
837 	caddr_t modptr, baseptr, sizeptr, dynptr;
838 	char *type;
839 	elf_file_t ef;
840 	linker_file_t lf;
841 	int error;
842 	vm_offset_t dp;
843 
844 	/* Look to see if we have the file preloaded */
845 	modptr = preload_search_by_name(filename);
846 	if (modptr == NULL)
847 		return (ENOENT);
848 
849 	type = (char *)preload_search_info(modptr, MODINFO_TYPE);
850 	baseptr = preload_search_info(modptr, MODINFO_ADDR);
851 	sizeptr = preload_search_info(modptr, MODINFO_SIZE);
852 	dynptr = preload_search_info(modptr,
853 	    MODINFO_METADATA | MODINFOMD_DYNAMIC);
854 	if (type == NULL ||
855 	    (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
856 	     strcmp(type, "elf module") != 0))
857 		return (EFTYPE);
858 	if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
859 		return (EINVAL);
860 
861 	lf = linker_make_file(filename, &link_elf_class);
862 	if (lf == NULL)
863 		return (ENOMEM);
864 
865 	ef = (elf_file_t) lf;
866 	ef->preloaded = 1;
867 	ef->modptr = modptr;
868 	ef->address = *(caddr_t *)baseptr;
869 #ifdef SPARSE_MAPPING
870 	ef->object = NULL;
871 #endif
872 	dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
873 	ef->dynamic = (Elf_Dyn *)dp;
874 	lf->address = ef->address;
875 	lf->size = *(size_t *)sizeptr;
876 
877 	ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
878 	    MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
879 	ctors_sizep = (Elf_Size *)preload_search_info(modptr,
880 	    MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
881 	if (ctors_addrp != NULL && ctors_sizep != NULL) {
882 		lf->ctors_addr = ef->address + *ctors_addrp;
883 		lf->ctors_size = *ctors_sizep;
884 	}
885 
886 #ifdef __arm__
887 	link_elf_locate_exidx_preload(lf, modptr);
888 #endif
889 
890 	error = parse_dynamic(ef);
891 	if (error == 0)
892 		error = parse_dpcpu(ef);
893 #ifdef VIMAGE
894 	if (error == 0)
895 		error = parse_vnet(ef);
896 #endif
897 	if (error == 0)
898 		error = preload_protect(ef, VM_PROT_ALL);
899 	if (error != 0) {
900 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
901 		return (error);
902 	}
903 	link_elf_reloc_local(lf);
904 	*result = lf;
905 	return (0);
906 }
907 
908 static int
909 link_elf_link_preload_finish(linker_file_t lf)
910 {
911 	elf_file_t ef;
912 	int error;
913 
914 	ef = (elf_file_t) lf;
915 	error = relocate_file(ef);
916 	if (error == 0)
917 		error = preload_protect(ef, VM_PROT_NONE);
918 	if (error != 0)
919 		return (error);
920 	(void)link_elf_preload_parse_symbols(ef);
921 
922 	return (link_elf_link_common_finish(lf));
923 }
924 
925 static int
926 link_elf_load_file(linker_class_t cls, const char* filename,
927     linker_file_t* result)
928 {
929 	struct nameidata nd;
930 	struct thread* td = curthread;	/* XXX */
931 	Elf_Ehdr *hdr;
932 	caddr_t firstpage, segbase;
933 	int nbytes, i;
934 	Elf_Phdr *phdr;
935 	Elf_Phdr *phlimit;
936 	Elf_Phdr *segs[MAXSEGS];
937 	int nsegs;
938 	Elf_Phdr *phdyn;
939 	caddr_t mapbase;
940 	size_t mapsize;
941 	Elf_Addr base_vaddr;
942 	Elf_Addr base_vlimit;
943 	int error = 0;
944 	ssize_t resid;
945 	int flags;
946 	elf_file_t ef;
947 	linker_file_t lf;
948 	Elf_Shdr *shdr;
949 	int symtabindex;
950 	int symstrindex;
951 	int shstrindex;
952 	int symcnt;
953 	int strcnt;
954 	char *shstrs;
955 
956 	shdr = NULL;
957 	lf = NULL;
958 	shstrs = NULL;
959 
960 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
961 	flags = FREAD;
962 	error = vn_open(&nd, &flags, 0, NULL);
963 	if (error != 0)
964 		return (error);
965 	NDFREE(&nd, NDF_ONLY_PNBUF);
966 	if (nd.ni_vp->v_type != VREG) {
967 		error = ENOEXEC;
968 		firstpage = NULL;
969 		goto out;
970 	}
971 #ifdef MAC
972 	error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
973 	if (error != 0) {
974 		firstpage = NULL;
975 		goto out;
976 	}
977 #endif
978 
979 	/*
980 	 * Read the elf header from the file.
981 	 */
982 	firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
983 	hdr = (Elf_Ehdr *)firstpage;
984 	error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
985 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
986 	    &resid, td);
987 	nbytes = PAGE_SIZE - resid;
988 	if (error != 0)
989 		goto out;
990 
991 	if (!IS_ELF(*hdr)) {
992 		error = ENOEXEC;
993 		goto out;
994 	}
995 
996 	if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
997 	    hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
998 		link_elf_error(filename, "Unsupported file layout");
999 		error = ENOEXEC;
1000 		goto out;
1001 	}
1002 	if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
1003 	    hdr->e_version != EV_CURRENT) {
1004 		link_elf_error(filename, "Unsupported file version");
1005 		error = ENOEXEC;
1006 		goto out;
1007 	}
1008 	if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
1009 		error = ENOSYS;
1010 		goto out;
1011 	}
1012 	if (hdr->e_machine != ELF_TARG_MACH) {
1013 		link_elf_error(filename, "Unsupported machine");
1014 		error = ENOEXEC;
1015 		goto out;
1016 	}
1017 
1018 	/*
1019 	 * We rely on the program header being in the first page.
1020 	 * This is not strictly required by the ABI specification, but
1021 	 * it seems to always true in practice.  And, it simplifies
1022 	 * things considerably.
1023 	 */
1024 	if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
1025 	      (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
1026 	      (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
1027 		link_elf_error(filename, "Unreadable program headers");
1028 
1029 	/*
1030 	 * Scan the program header entries, and save key information.
1031 	 *
1032 	 * We rely on there being exactly two load segments, text and data,
1033 	 * in that order.
1034 	 */
1035 	phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
1036 	phlimit = phdr + hdr->e_phnum;
1037 	nsegs = 0;
1038 	phdyn = NULL;
1039 	while (phdr < phlimit) {
1040 		switch (phdr->p_type) {
1041 		case PT_LOAD:
1042 			if (nsegs == MAXSEGS) {
1043 				link_elf_error(filename, "Too many sections");
1044 				error = ENOEXEC;
1045 				goto out;
1046 			}
1047 			/*
1048 			 * XXX: We just trust they come in right order ??
1049 			 */
1050 			segs[nsegs] = phdr;
1051 			++nsegs;
1052 			break;
1053 
1054 		case PT_DYNAMIC:
1055 			phdyn = phdr;
1056 			break;
1057 
1058 		case PT_INTERP:
1059 			error = ENOSYS;
1060 			goto out;
1061 		}
1062 
1063 		++phdr;
1064 	}
1065 	if (phdyn == NULL) {
1066 		link_elf_error(filename, "Object is not dynamically-linked");
1067 		error = ENOEXEC;
1068 		goto out;
1069 	}
1070 	if (nsegs == 0) {
1071 		link_elf_error(filename, "No sections");
1072 		error = ENOEXEC;
1073 		goto out;
1074 	}
1075 
1076 	/*
1077 	 * Allocate the entire address space of the object, to stake
1078 	 * out our contiguous region, and to establish the base
1079 	 * address for relocation.
1080 	 */
1081 	base_vaddr = trunc_page(segs[0]->p_vaddr);
1082 	base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
1083 	    segs[nsegs - 1]->p_memsz);
1084 	mapsize = base_vlimit - base_vaddr;
1085 
1086 	lf = linker_make_file(filename, &link_elf_class);
1087 	if (lf == NULL) {
1088 		error = ENOMEM;
1089 		goto out;
1090 	}
1091 
1092 	ef = (elf_file_t) lf;
1093 #ifdef SPARSE_MAPPING
1094 	ef->object = vm_object_allocate(OBJT_PHYS, atop(mapsize));
1095 	if (ef->object == NULL) {
1096 		error = ENOMEM;
1097 		goto out;
1098 	}
1099 #ifdef __amd64__
1100 	mapbase = (caddr_t)KERNBASE;
1101 #else
1102 	mapbase = (caddr_t)vm_map_min(kernel_map);
1103 #endif
1104 	/*
1105 	 * Mapping protections are downgraded after relocation processing.
1106 	 */
1107 	error = vm_map_find(kernel_map, ef->object, 0,
1108 	    (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE,
1109 	    VM_PROT_ALL, VM_PROT_ALL, 0);
1110 	if (error != 0) {
1111 		vm_object_deallocate(ef->object);
1112 		ef->object = NULL;
1113 		goto out;
1114 	}
1115 #else
1116 	mapbase = malloc(mapsize, M_LINKER, M_EXEC | M_WAITOK);
1117 #endif
1118 	ef->address = mapbase;
1119 
1120 	/*
1121 	 * Read the text and data sections and zero the bss.
1122 	 */
1123 	for (i = 0; i < nsegs; i++) {
1124 		segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1125 
1126 #ifdef SPARSE_MAPPING
1127 		/*
1128 		 * Consecutive segments may have different mapping permissions,
1129 		 * so be strict and verify that their mappings do not overlap.
1130 		 */
1131 		if (((vm_offset_t)segbase & PAGE_MASK) != 0) {
1132 			error = EINVAL;
1133 			goto out;
1134 		}
1135 
1136 		error = vm_map_wire(kernel_map,
1137 		    (vm_offset_t)segbase,
1138 		    (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1139 		    VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
1140 		if (error != KERN_SUCCESS) {
1141 			error = ENOMEM;
1142 			goto out;
1143 		}
1144 #endif
1145 
1146 		error = vn_rdwr(UIO_READ, nd.ni_vp,
1147 		    segbase, segs[i]->p_filesz, segs[i]->p_offset,
1148 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1149 		    &resid, td);
1150 		if (error != 0)
1151 			goto out;
1152 		bzero(segbase + segs[i]->p_filesz,
1153 		    segs[i]->p_memsz - segs[i]->p_filesz);
1154 	}
1155 
1156 #ifdef GPROF
1157 	/* Update profiling information with the new text segment. */
1158 	mtx_lock(&Giant);
1159 	kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
1160 	    segs[0]->p_memsz));
1161 	mtx_unlock(&Giant);
1162 #endif
1163 
1164 	ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
1165 
1166 	lf->address = ef->address;
1167 	lf->size = mapsize;
1168 
1169 	error = parse_dynamic(ef);
1170 	if (error != 0)
1171 		goto out;
1172 	error = parse_dpcpu(ef);
1173 	if (error != 0)
1174 		goto out;
1175 #ifdef VIMAGE
1176 	error = parse_vnet(ef);
1177 	if (error != 0)
1178 		goto out;
1179 #endif
1180 	link_elf_reloc_local(lf);
1181 
1182 	VOP_UNLOCK(nd.ni_vp);
1183 	error = linker_load_dependencies(lf);
1184 	vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1185 	if (error != 0)
1186 		goto out;
1187 	error = relocate_file(ef);
1188 	if (error != 0)
1189 		goto out;
1190 
1191 #ifdef SPARSE_MAPPING
1192 	/*
1193 	 * Downgrade permissions on text segment mappings now that relocation
1194 	 * processing is complete.  Restrict permissions on read-only segments.
1195 	 */
1196 	for (i = 0; i < nsegs; i++) {
1197 		vm_prot_t prot;
1198 
1199 		if (segs[i]->p_type != PT_LOAD)
1200 			continue;
1201 
1202 		prot = VM_PROT_READ;
1203 		if ((segs[i]->p_flags & PF_W) != 0)
1204 			prot |= VM_PROT_WRITE;
1205 		if ((segs[i]->p_flags & PF_X) != 0)
1206 			prot |= VM_PROT_EXECUTE;
1207 		segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1208 		error = vm_map_protect(kernel_map,
1209 		    (vm_offset_t)segbase,
1210 		    (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1211 		    prot, FALSE);
1212 		if (error != KERN_SUCCESS) {
1213 			error = ENOMEM;
1214 			goto out;
1215 		}
1216 	}
1217 #endif
1218 
1219 	/*
1220 	 * Try and load the symbol table if it's present.  (you can
1221 	 * strip it!)
1222 	 */
1223 	nbytes = hdr->e_shnum * hdr->e_shentsize;
1224 	if (nbytes == 0 || hdr->e_shoff == 0)
1225 		goto nosyms;
1226 	shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1227 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1228 	    (caddr_t)shdr, nbytes, hdr->e_shoff,
1229 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1230 	    &resid, td);
1231 	if (error != 0)
1232 		goto out;
1233 
1234 	/* Read section string table */
1235 	shstrindex = hdr->e_shstrndx;
1236 	if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1237 	    shdr[shstrindex].sh_size != 0) {
1238 		nbytes = shdr[shstrindex].sh_size;
1239 		shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1240 		error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1241 		    shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1242 		    td->td_ucred, NOCRED, &resid, td);
1243 		if (error)
1244 			goto out;
1245 	}
1246 
1247 	symtabindex = -1;
1248 	symstrindex = -1;
1249 	for (i = 0; i < hdr->e_shnum; i++) {
1250 		if (shdr[i].sh_type == SHT_SYMTAB) {
1251 			symtabindex = i;
1252 			symstrindex = shdr[i].sh_link;
1253 		} else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1254 		    strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1255 			/* Record relocated address and size of .ctors. */
1256 			lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1257 			lf->ctors_size = shdr[i].sh_size;
1258 		}
1259 	}
1260 	if (symtabindex < 0 || symstrindex < 0)
1261 		goto nosyms;
1262 
1263 	symcnt = shdr[symtabindex].sh_size;
1264 	ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1265 	strcnt = shdr[symstrindex].sh_size;
1266 	ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1267 
1268 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1269 	    ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1270 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1271 	    &resid, td);
1272 	if (error != 0)
1273 		goto out;
1274 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1275 	    ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1276 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1277 	    &resid, td);
1278 	if (error != 0)
1279 		goto out;
1280 
1281 	ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1282 	ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1283 	ef->ddbstrcnt = strcnt;
1284 	ef->ddbstrtab = ef->strbase;
1285 
1286 nosyms:
1287 
1288 #ifdef __arm__
1289 	link_elf_locate_exidx(lf, shdr, hdr->e_shnum);
1290 #endif
1291 
1292 	error = link_elf_link_common_finish(lf);
1293 	if (error != 0)
1294 		goto out;
1295 
1296 	*result = lf;
1297 
1298 out:
1299 	VOP_UNLOCK(nd.ni_vp);
1300 	vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1301 	if (error != 0 && lf != NULL)
1302 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1303 	free(shdr, M_LINKER);
1304 	free(firstpage, M_LINKER);
1305 	free(shstrs, M_LINKER);
1306 
1307 	return (error);
1308 }
1309 
1310 Elf_Addr
1311 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1312 {
1313 	elf_file_t ef;
1314 
1315 	KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class,
1316 	    ("elf_relocaddr: unexpected linker file %p", lf));
1317 
1318 	ef = (elf_file_t)lf;
1319 	if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1320 		return ((x - ef->pcpu_start) + ef->pcpu_base);
1321 #ifdef VIMAGE
1322 	if (x >= ef->vnet_start && x < ef->vnet_stop)
1323 		return ((x - ef->vnet_start) + ef->vnet_base);
1324 #endif
1325 	return (x);
1326 }
1327 
1328 static void
1329 link_elf_unload_file(linker_file_t file)
1330 {
1331 	elf_file_t ef = (elf_file_t) file;
1332 
1333 	if (ef->pcpu_base != 0) {
1334 		dpcpu_free((void *)ef->pcpu_base,
1335 		    ef->pcpu_stop - ef->pcpu_start);
1336 		elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1337 	}
1338 #ifdef VIMAGE
1339 	if (ef->vnet_base != 0) {
1340 		vnet_data_free((void *)ef->vnet_base,
1341 		    ef->vnet_stop - ef->vnet_start);
1342 		elf_set_delete(&set_vnet_list, ef->vnet_start);
1343 	}
1344 #endif
1345 #ifdef GDB
1346 	if (ef->gdb.l_ld != NULL) {
1347 		GDB_STATE(RT_DELETE);
1348 		free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1349 		link_elf_delete_gdb(&ef->gdb);
1350 		GDB_STATE(RT_CONSISTENT);
1351 	}
1352 #endif
1353 
1354 	/* Notify MD code that a module is being unloaded. */
1355 	elf_cpu_unload_file(file);
1356 
1357 	if (ef->preloaded) {
1358 		link_elf_unload_preload(file);
1359 		return;
1360 	}
1361 
1362 #ifdef SPARSE_MAPPING
1363 	if (ef->object != NULL) {
1364 		vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1365 		    (vm_offset_t) ef->address
1366 		    + (ef->object->size << PAGE_SHIFT));
1367 	}
1368 #else
1369 	free(ef->address, M_LINKER);
1370 #endif
1371 	free(ef->symbase, M_LINKER);
1372 	free(ef->strbase, M_LINKER);
1373 	free(ef->ctftab, M_LINKER);
1374 	free(ef->ctfoff, M_LINKER);
1375 	free(ef->typoff, M_LINKER);
1376 }
1377 
1378 static void
1379 link_elf_unload_preload(linker_file_t file)
1380 {
1381 
1382 	if (file->pathname != NULL)
1383 		preload_delete_name(file->pathname);
1384 }
1385 
1386 static const char *
1387 symbol_name(elf_file_t ef, Elf_Size r_info)
1388 {
1389 	const Elf_Sym *ref;
1390 
1391 	if (ELF_R_SYM(r_info)) {
1392 		ref = ef->symtab + ELF_R_SYM(r_info);
1393 		return (ef->strtab + ref->st_name);
1394 	}
1395 	return (NULL);
1396 }
1397 
1398 static int
1399 symbol_type(elf_file_t ef, Elf_Size r_info)
1400 {
1401 	const Elf_Sym *ref;
1402 
1403 	if (ELF_R_SYM(r_info)) {
1404 		ref = ef->symtab + ELF_R_SYM(r_info);
1405 		return (ELF_ST_TYPE(ref->st_info));
1406 	}
1407 	return (STT_NOTYPE);
1408 }
1409 
1410 static int
1411 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc,
1412     bool ifuncs)
1413 {
1414 	const Elf_Rel *rel;
1415 	const Elf_Rela *rela;
1416 	const char *symname;
1417 
1418 #define	APPLY_RELOCS(iter, tbl, tblsize, type) do {			\
1419 	for ((iter) = (tbl); (iter) != NULL &&				\
1420 	    (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) {	\
1421 		if ((symbol_type(ef, (iter)->r_info) ==			\
1422 		    STT_GNU_IFUNC ||					\
1423 		    elf_is_ifunc_reloc((iter)->r_info)) != ifuncs)	\
1424 			continue;					\
1425 		if (reloc(&ef->lf, (Elf_Addr)ef->address,		\
1426 		    (iter), (type), lookup)) {				\
1427 			symname = symbol_name(ef, (iter)->r_info);	\
1428 			printf("link_elf: symbol %s undefined\n",	\
1429 			    symname);					\
1430 			return (ENOENT);				\
1431 		}							\
1432 	}								\
1433 } while (0)
1434 
1435 	APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL);
1436 	APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA);
1437 	APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL);
1438 	APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA);
1439 
1440 #undef APPLY_RELOCS
1441 
1442 	return (0);
1443 }
1444 
1445 static int
1446 relocate_file(elf_file_t ef)
1447 {
1448 	int error;
1449 
1450 	error = relocate_file1(ef, elf_lookup, elf_reloc, false);
1451 	if (error == 0)
1452 		error = relocate_file1(ef, elf_lookup, elf_reloc, true);
1453 	return (error);
1454 }
1455 
1456 /*
1457  * Hash function for symbol table lookup.  Don't even think about changing
1458  * this.  It is specified by the System V ABI.
1459  */
1460 static unsigned long
1461 elf_hash(const char *name)
1462 {
1463 	const unsigned char *p = (const unsigned char *) name;
1464 	unsigned long h = 0;
1465 	unsigned long g;
1466 
1467 	while (*p != '\0') {
1468 		h = (h << 4) + *p++;
1469 		if ((g = h & 0xf0000000) != 0)
1470 			h ^= g >> 24;
1471 		h &= ~g;
1472 	}
1473 	return (h);
1474 }
1475 
1476 static int
1477 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1478 {
1479 	elf_file_t ef = (elf_file_t) lf;
1480 	unsigned long symnum;
1481 	const Elf_Sym* symp;
1482 	const char *strp;
1483 	unsigned long hash;
1484 	int i;
1485 
1486 	/* If we don't have a hash, bail. */
1487 	if (ef->buckets == NULL || ef->nbuckets == 0) {
1488 		printf("link_elf_lookup_symbol: missing symbol hash table\n");
1489 		return (ENOENT);
1490 	}
1491 
1492 	/* First, search hashed global symbols */
1493 	hash = elf_hash(name);
1494 	symnum = ef->buckets[hash % ef->nbuckets];
1495 
1496 	while (symnum != STN_UNDEF) {
1497 		if (symnum >= ef->nchains) {
1498 			printf("%s: corrupt symbol table\n", __func__);
1499 			return (ENOENT);
1500 		}
1501 
1502 		symp = ef->symtab + symnum;
1503 		if (symp->st_name == 0) {
1504 			printf("%s: corrupt symbol table\n", __func__);
1505 			return (ENOENT);
1506 		}
1507 
1508 		strp = ef->strtab + symp->st_name;
1509 
1510 		if (strcmp(name, strp) == 0) {
1511 			if (symp->st_shndx != SHN_UNDEF ||
1512 			    (symp->st_value != 0 &&
1513 			    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1514 			    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1515 				*sym = (c_linker_sym_t) symp;
1516 				return (0);
1517 			}
1518 			return (ENOENT);
1519 		}
1520 
1521 		symnum = ef->chains[symnum];
1522 	}
1523 
1524 	/* If we have not found it, look at the full table (if loaded) */
1525 	if (ef->symtab == ef->ddbsymtab)
1526 		return (ENOENT);
1527 
1528 	/* Exhaustive search */
1529 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1530 		strp = ef->ddbstrtab + symp->st_name;
1531 		if (strcmp(name, strp) == 0) {
1532 			if (symp->st_shndx != SHN_UNDEF ||
1533 			    (symp->st_value != 0 &&
1534 			    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1535 			    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1536 				*sym = (c_linker_sym_t) symp;
1537 				return (0);
1538 			}
1539 			return (ENOENT);
1540 		}
1541 	}
1542 
1543 	return (ENOENT);
1544 }
1545 
1546 static int
1547 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1548     linker_symval_t *symval)
1549 {
1550 	elf_file_t ef;
1551 	const Elf_Sym *es;
1552 	caddr_t val;
1553 
1554 	ef = (elf_file_t)lf;
1555 	es = (const Elf_Sym *)sym;
1556 	if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
1557 		symval->name = ef->strtab + es->st_name;
1558 		val = (caddr_t)ef->address + es->st_value;
1559 		if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1560 			val = ((caddr_t (*)(void))val)();
1561 		symval->value = val;
1562 		symval->size = es->st_size;
1563 		return (0);
1564 	}
1565 	if (ef->symtab == ef->ddbsymtab)
1566 		return (ENOENT);
1567 	if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1568 		symval->name = ef->ddbstrtab + es->st_name;
1569 		val = (caddr_t)ef->address + es->st_value;
1570 		if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1571 			val = ((caddr_t (*)(void))val)();
1572 		symval->value = val;
1573 		symval->size = es->st_size;
1574 		return (0);
1575 	}
1576 	return (ENOENT);
1577 }
1578 
1579 static int
1580 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1581     c_linker_sym_t *sym, long *diffp)
1582 {
1583 	elf_file_t ef = (elf_file_t) lf;
1584 	u_long off = (uintptr_t) (void *) value;
1585 	u_long diff = off;
1586 	u_long st_value;
1587 	const Elf_Sym* es;
1588 	const Elf_Sym* best = NULL;
1589 	int i;
1590 
1591 	for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1592 		if (es->st_name == 0)
1593 			continue;
1594 		st_value = es->st_value + (uintptr_t) (void *) ef->address;
1595 		if (off >= st_value) {
1596 			if (off - st_value < diff) {
1597 				diff = off - st_value;
1598 				best = es;
1599 				if (diff == 0)
1600 					break;
1601 			} else if (off - st_value == diff) {
1602 				best = es;
1603 			}
1604 		}
1605 	}
1606 	if (best == NULL)
1607 		*diffp = off;
1608 	else
1609 		*diffp = diff;
1610 	*sym = (c_linker_sym_t) best;
1611 
1612 	return (0);
1613 }
1614 
1615 /*
1616  * Look up a linker set on an ELF system.
1617  */
1618 static int
1619 link_elf_lookup_set(linker_file_t lf, const char *name,
1620     void ***startp, void ***stopp, int *countp)
1621 {
1622 	c_linker_sym_t sym;
1623 	linker_symval_t symval;
1624 	char *setsym;
1625 	void **start, **stop;
1626 	int len, error = 0, count;
1627 
1628 	len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1629 	setsym = malloc(len, M_LINKER, M_WAITOK);
1630 
1631 	/* get address of first entry */
1632 	snprintf(setsym, len, "%s%s", "__start_set_", name);
1633 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1634 	if (error != 0)
1635 		goto out;
1636 	link_elf_symbol_values(lf, sym, &symval);
1637 	if (symval.value == 0) {
1638 		error = ESRCH;
1639 		goto out;
1640 	}
1641 	start = (void **)symval.value;
1642 
1643 	/* get address of last entry */
1644 	snprintf(setsym, len, "%s%s", "__stop_set_", name);
1645 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1646 	if (error != 0)
1647 		goto out;
1648 	link_elf_symbol_values(lf, sym, &symval);
1649 	if (symval.value == 0) {
1650 		error = ESRCH;
1651 		goto out;
1652 	}
1653 	stop = (void **)symval.value;
1654 
1655 	/* and the number of entries */
1656 	count = stop - start;
1657 
1658 	/* and copy out */
1659 	if (startp != NULL)
1660 		*startp = start;
1661 	if (stopp != NULL)
1662 		*stopp = stop;
1663 	if (countp != NULL)
1664 		*countp = count;
1665 
1666 out:
1667 	free(setsym, M_LINKER);
1668 	return (error);
1669 }
1670 
1671 static int
1672 link_elf_each_function_name(linker_file_t file,
1673   int (*callback)(const char *, void *), void *opaque)
1674 {
1675 	elf_file_t ef = (elf_file_t)file;
1676 	const Elf_Sym *symp;
1677 	int i, error;
1678 
1679 	/* Exhaustive search */
1680 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1681 		if (symp->st_value != 0 &&
1682 		    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1683 		    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1684 			error = callback(ef->ddbstrtab + symp->st_name, opaque);
1685 			if (error != 0)
1686 				return (error);
1687 		}
1688 	}
1689 	return (0);
1690 }
1691 
1692 static int
1693 link_elf_each_function_nameval(linker_file_t file,
1694     linker_function_nameval_callback_t callback, void *opaque)
1695 {
1696 	linker_symval_t symval;
1697 	elf_file_t ef = (elf_file_t)file;
1698 	const Elf_Sym* symp;
1699 	int i, error;
1700 
1701 	/* Exhaustive search */
1702 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1703 		if (symp->st_value != 0 &&
1704 		    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1705 		    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1706 			error = link_elf_symbol_values(file,
1707 			    (c_linker_sym_t) symp, &symval);
1708 			if (error != 0)
1709 				return (error);
1710 			error = callback(file, i, &symval, opaque);
1711 			if (error != 0)
1712 				return (error);
1713 		}
1714 	}
1715 	return (0);
1716 }
1717 
1718 const Elf_Sym *
1719 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1720 {
1721 	elf_file_t ef = (elf_file_t)lf;
1722 
1723 	if (symidx >= ef->nchains)
1724 		return (NULL);
1725 	return (ef->symtab + symidx);
1726 }
1727 
1728 const char *
1729 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1730 {
1731 	elf_file_t ef = (elf_file_t)lf;
1732 	const Elf_Sym *sym;
1733 
1734 	if (symidx >= ef->nchains)
1735 		return (NULL);
1736 	sym = ef->symtab + symidx;
1737 	return (ef->strtab + sym->st_name);
1738 }
1739 
1740 /*
1741  * Symbol lookup function that can be used when the symbol index is known (ie
1742  * in relocations). It uses the symbol index instead of doing a fully fledged
1743  * hash table based lookup when such is valid. For example for local symbols.
1744  * This is not only more efficient, it's also more correct. It's not always
1745  * the case that the symbol can be found through the hash table.
1746  */
1747 static int
1748 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1749 {
1750 	elf_file_t ef = (elf_file_t)lf;
1751 	const Elf_Sym *sym;
1752 	const char *symbol;
1753 	Elf_Addr addr, start, base;
1754 
1755 	/* Don't even try to lookup the symbol if the index is bogus. */
1756 	if (symidx >= ef->nchains) {
1757 		*res = 0;
1758 		return (EINVAL);
1759 	}
1760 
1761 	sym = ef->symtab + symidx;
1762 
1763 	/*
1764 	 * Don't do a full lookup when the symbol is local. It may even
1765 	 * fail because it may not be found through the hash table.
1766 	 */
1767 	if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1768 		/* Force lookup failure when we have an insanity. */
1769 		if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1770 			*res = 0;
1771 			return (EINVAL);
1772 		}
1773 		*res = ((Elf_Addr)ef->address + sym->st_value);
1774 		return (0);
1775 	}
1776 
1777 	/*
1778 	 * XXX we can avoid doing a hash table based lookup for global
1779 	 * symbols as well. This however is not always valid, so we'll
1780 	 * just do it the hard way for now. Performance tweaks can
1781 	 * always be added.
1782 	 */
1783 
1784 	symbol = ef->strtab + sym->st_name;
1785 
1786 	/* Force a lookup failure if the symbol name is bogus. */
1787 	if (*symbol == 0) {
1788 		*res = 0;
1789 		return (EINVAL);
1790 	}
1791 
1792 	addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1793 	if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1794 		*res = 0;
1795 		return (EINVAL);
1796 	}
1797 
1798 	if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1799 		addr = addr - start + base;
1800 #ifdef VIMAGE
1801 	else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1802 		addr = addr - start + base;
1803 #endif
1804 	*res = addr;
1805 	return (0);
1806 }
1807 
1808 static void
1809 link_elf_reloc_local(linker_file_t lf)
1810 {
1811 	const Elf_Rel *rellim;
1812 	const Elf_Rel *rel;
1813 	const Elf_Rela *relalim;
1814 	const Elf_Rela *rela;
1815 	elf_file_t ef = (elf_file_t)lf;
1816 
1817 	/* Perform relocations without addend if there are any: */
1818 	if ((rel = ef->rel) != NULL) {
1819 		rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1820 		while (rel < rellim) {
1821 			elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1822 			    ELF_RELOC_REL, elf_lookup);
1823 			rel++;
1824 		}
1825 	}
1826 
1827 	/* Perform relocations with addend if there are any: */
1828 	if ((rela = ef->rela) != NULL) {
1829 		relalim = (const Elf_Rela *)
1830 		    ((const char *)ef->rela + ef->relasize);
1831 		while (rela < relalim) {
1832 			elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1833 			    ELF_RELOC_RELA, elf_lookup);
1834 			rela++;
1835 		}
1836 	}
1837 }
1838 
1839 static long
1840 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1841 {
1842 	elf_file_t ef = (elf_file_t)lf;
1843 
1844 	*symtab = ef->ddbsymtab;
1845 
1846 	if (*symtab == NULL)
1847 		return (0);
1848 
1849 	return (ef->ddbsymcnt);
1850 }
1851 
1852 static long
1853 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1854 {
1855 	elf_file_t ef = (elf_file_t)lf;
1856 
1857 	*strtab = ef->ddbstrtab;
1858 
1859 	if (*strtab == NULL)
1860 		return (0);
1861 
1862 	return (ef->ddbstrcnt);
1863 }
1864 
1865 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) || defined(__powerpc__)
1866 /*
1867  * Use this lookup routine when performing relocations early during boot.
1868  * The generic lookup routine depends on kobj, which is not initialized
1869  * at that point.
1870  */
1871 static int
1872 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused,
1873     Elf_Addr *res)
1874 {
1875 	elf_file_t ef;
1876 	const Elf_Sym *symp;
1877 	caddr_t val;
1878 
1879 	ef = (elf_file_t)lf;
1880 	symp = ef->symtab + symidx;
1881 	if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) {
1882 		val = (caddr_t)ef->address + symp->st_value;
1883 		*res = ((Elf_Addr (*)(void))val)();
1884 		return (0);
1885 	}
1886 	return (ENOENT);
1887 }
1888 
1889 void
1890 link_elf_ireloc(caddr_t kmdp)
1891 {
1892 	struct elf_file eff;
1893 	elf_file_t ef;
1894 
1895 	ef = &eff;
1896 
1897 	bzero_early(ef, sizeof(*ef));
1898 
1899 	ef->modptr = kmdp;
1900 	ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
1901 
1902 #ifdef RELOCATABLE_KERNEL
1903 	ef->address = (caddr_t) (__startkernel - KERNBASE);
1904 #else
1905 	ef->address = 0;
1906 #endif
1907 	parse_dynamic(ef);
1908 
1909 	link_elf_preload_parse_symbols(ef);
1910 	relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true);
1911 }
1912 #endif
1913