xref: /freebsd/sys/kern/link_elf.c (revision 4543ef516683042d46f3bd3bb8a4f3f746e00499)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 #include "opt_ddb.h"
31 #include "opt_gdb.h"
32 
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/kernel.h>
36 #include <sys/lock.h>
37 #include <sys/malloc.h>
38 #ifdef SPARSE_MAPPING
39 #include <sys/mman.h>
40 #endif
41 #include <sys/mutex.h>
42 #include <sys/mount.h>
43 #include <sys/pcpu.h>
44 #include <sys/proc.h>
45 #include <sys/namei.h>
46 #include <sys/fcntl.h>
47 #include <sys/vnode.h>
48 #include <sys/linker.h>
49 #include <sys/sysctl.h>
50 #include <sys/tslog.h>
51 
52 #include <machine/elf.h>
53 
54 #include <net/vnet.h>
55 
56 #include <security/mac/mac_framework.h>
57 
58 #include <vm/vm.h>
59 #include <vm/vm_param.h>
60 #ifdef SPARSE_MAPPING
61 #include <vm/vm_object.h>
62 #include <vm/vm_kern.h>
63 #include <vm/vm_extern.h>
64 #endif
65 #include <vm/pmap.h>
66 #include <vm/vm_map.h>
67 
68 #include <sys/link_elf.h>
69 
70 #include "linker_if.h"
71 
72 #define MAXSEGS 4
73 
74 typedef struct elf_file {
75 	struct linker_file lf;		/* Common fields */
76 	int		preloaded;	/* Was file pre-loaded */
77 	caddr_t		address;	/* Relocation address */
78 #ifdef SPARSE_MAPPING
79 	vm_object_t	object;		/* VM object to hold file pages */
80 #endif
81 	Elf_Dyn		*dynamic;	/* Symbol table etc. */
82 	Elf_Hashelt	nbuckets;	/* DT_HASH info */
83 	Elf_Hashelt	nchains;
84 	const Elf_Hashelt *buckets;
85 	const Elf_Hashelt *chains;
86 	caddr_t		hash;
87 	caddr_t		strtab;		/* DT_STRTAB */
88 	int		strsz;		/* DT_STRSZ */
89 	const Elf_Sym	*symtab;		/* DT_SYMTAB */
90 	Elf_Addr	*got;		/* DT_PLTGOT */
91 	const Elf_Rel	*pltrel;	/* DT_JMPREL */
92 	int		pltrelsize;	/* DT_PLTRELSZ */
93 	const Elf_Rela	*pltrela;	/* DT_JMPREL */
94 	int		pltrelasize;	/* DT_PLTRELSZ */
95 	const Elf_Rel	*rel;		/* DT_REL */
96 	int		relsize;	/* DT_RELSZ */
97 	const Elf_Rela	*rela;		/* DT_RELA */
98 	int		relasize;	/* DT_RELASZ */
99 	caddr_t		modptr;
100 	const Elf_Sym	*ddbsymtab;	/* The symbol table we are using */
101 	long		ddbsymcnt;	/* Number of symbols */
102 	caddr_t		ddbstrtab;	/* String table */
103 	long		ddbstrcnt;	/* number of bytes in string table */
104 	caddr_t		symbase;	/* malloc'ed symbold base */
105 	caddr_t		strbase;	/* malloc'ed string base */
106 	caddr_t		ctftab;		/* CTF table */
107 	long		ctfcnt;		/* number of bytes in CTF table */
108 	caddr_t		ctfoff;		/* CTF offset table */
109 	caddr_t		typoff;		/* Type offset table */
110 	long		typlen;		/* Number of type entries. */
111 	Elf_Addr	pcpu_start;	/* Pre-relocation pcpu set start. */
112 	Elf_Addr	pcpu_stop;	/* Pre-relocation pcpu set stop. */
113 	Elf_Addr	pcpu_base;	/* Relocated pcpu set address. */
114 #ifdef VIMAGE
115 	Elf_Addr	vnet_start;	/* Pre-relocation vnet set start. */
116 	Elf_Addr	vnet_stop;	/* Pre-relocation vnet set stop. */
117 	Elf_Addr	vnet_base;	/* Relocated vnet set address. */
118 #endif
119 #ifdef GDB
120 	struct link_map	gdb;		/* hooks for gdb */
121 #endif
122 } *elf_file_t;
123 
124 struct elf_set {
125 	Elf_Addr	es_start;
126 	Elf_Addr	es_stop;
127 	Elf_Addr	es_base;
128 	TAILQ_ENTRY(elf_set)	es_link;
129 };
130 
131 TAILQ_HEAD(elf_set_head, elf_set);
132 
133 #include <kern/kern_ctf.c>
134 
135 static int	link_elf_link_common_finish(linker_file_t);
136 static int	link_elf_link_preload(linker_class_t cls,
137 				      const char *, linker_file_t *);
138 static int	link_elf_link_preload_finish(linker_file_t);
139 static int	link_elf_load_file(linker_class_t, const char *,
140 		    linker_file_t *);
141 static int	link_elf_lookup_symbol(linker_file_t, const char *,
142 		    c_linker_sym_t *);
143 static int	link_elf_lookup_debug_symbol(linker_file_t, const char *,
144 		    c_linker_sym_t *);
145 static int	link_elf_symbol_values(linker_file_t, c_linker_sym_t,
146 		    linker_symval_t *);
147 static int	link_elf_debug_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 #ifdef VIMAGE
164 static void	link_elf_propagate_vnets(linker_file_t);
165 #endif
166 static int	elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
167 
168 static kobj_method_t link_elf_methods[] = {
169 	KOBJMETHOD(linker_lookup_symbol,	link_elf_lookup_symbol),
170 	KOBJMETHOD(linker_lookup_debug_symbol,	link_elf_lookup_debug_symbol),
171 	KOBJMETHOD(linker_symbol_values,	link_elf_symbol_values),
172 	KOBJMETHOD(linker_debug_symbol_values,	link_elf_debug_symbol_values),
173 	KOBJMETHOD(linker_search_symbol,	link_elf_search_symbol),
174 	KOBJMETHOD(linker_unload,		link_elf_unload_file),
175 	KOBJMETHOD(linker_load_file,		link_elf_load_file),
176 	KOBJMETHOD(linker_link_preload,		link_elf_link_preload),
177 	KOBJMETHOD(linker_link_preload_finish,	link_elf_link_preload_finish),
178 	KOBJMETHOD(linker_lookup_set,		link_elf_lookup_set),
179 	KOBJMETHOD(linker_each_function_name,	link_elf_each_function_name),
180 	KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
181 	KOBJMETHOD(linker_ctf_get,		link_elf_ctf_get),
182 	KOBJMETHOD(linker_symtab_get,		link_elf_symtab_get),
183 	KOBJMETHOD(linker_strtab_get,		link_elf_strtab_get),
184 #ifdef VIMAGE
185 	KOBJMETHOD(linker_propagate_vnets,	link_elf_propagate_vnets),
186 #endif
187 	KOBJMETHOD_END
188 };
189 
190 static struct linker_class link_elf_class = {
191 #if ELF_TARG_CLASS == ELFCLASS32
192 	"elf32",
193 #else
194 	"elf64",
195 #endif
196 	link_elf_methods, sizeof(struct elf_file)
197 };
198 
199 static bool link_elf_leak_locals = true;
200 SYSCTL_BOOL(_debug, OID_AUTO, link_elf_leak_locals,
201     CTLFLAG_RWTUN, &link_elf_leak_locals, 0,
202     "Allow local symbols to participate in global module symbol resolution");
203 
204 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase,
205     const void *data, int type, elf_lookup_fn lookup);
206 
207 static int	parse_dynamic(elf_file_t);
208 static int	relocate_file(elf_file_t);
209 static int	relocate_file1(elf_file_t ef, elf_lookup_fn lookup,
210 		    elf_reloc_fn reloc, bool ifuncs);
211 static int	link_elf_preload_parse_symbols(elf_file_t);
212 
213 static struct elf_set_head set_pcpu_list;
214 #ifdef VIMAGE
215 static struct elf_set_head set_vnet_list;
216 #endif
217 
218 static void
219 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
220 {
221 	struct elf_set *set, *iter;
222 
223 	set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
224 	set->es_start = start;
225 	set->es_stop = stop;
226 	set->es_base = base;
227 
228 	TAILQ_FOREACH(iter, list, es_link) {
229 		KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
230 		    (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
231 		    ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
232 		    (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
233 		    (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
234 
235 		if (iter->es_start > set->es_start) {
236 			TAILQ_INSERT_BEFORE(iter, set, es_link);
237 			break;
238 		}
239 	}
240 
241 	if (iter == NULL)
242 		TAILQ_INSERT_TAIL(list, set, es_link);
243 }
244 
245 static int
246 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
247 {
248 	struct elf_set *set;
249 
250 	TAILQ_FOREACH(set, list, es_link) {
251 		if (addr < set->es_start)
252 			return (0);
253 		if (addr < set->es_stop) {
254 			*start = set->es_start;
255 			*base = set->es_base;
256 			return (1);
257 		}
258 	}
259 
260 	return (0);
261 }
262 
263 static void
264 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
265 {
266 	struct elf_set *set;
267 
268 	TAILQ_FOREACH(set, list, es_link) {
269 		if (start < set->es_start)
270 			break;
271 		if (start == set->es_start) {
272 			TAILQ_REMOVE(list, set, es_link);
273 			free(set, M_LINKER);
274 			return;
275 		}
276 	}
277 	KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
278 	    (uintmax_t)start));
279 }
280 
281 #ifdef GDB
282 static void	r_debug_state(struct r_debug *, struct link_map *);
283 
284 /*
285  * A list of loaded modules for GDB to use for loading symbols.
286  */
287 struct r_debug r_debug;
288 
289 #define GDB_STATE(s) do {				\
290 	r_debug.r_state = s; r_debug_state(NULL, NULL);	\
291 } while (0)
292 
293 /*
294  * Function for the debugger to set a breakpoint on to gain control.
295  */
296 static void
297 r_debug_state(struct r_debug *dummy_one __unused,
298 	      struct link_map *dummy_two __unused)
299 {
300 }
301 
302 static void
303 link_elf_add_gdb(struct link_map *l)
304 {
305 	struct link_map *prev;
306 
307 	l->l_next = NULL;
308 
309 	if (r_debug.r_map == NULL) {
310 		/* Add first. */
311 		l->l_prev = NULL;
312 		r_debug.r_map = l;
313 	} else {
314 		/* Append to list. */
315 		for (prev = r_debug.r_map;
316 		    prev->l_next != NULL;
317 		    prev = prev->l_next)
318 			;
319 		l->l_prev = prev;
320 		prev->l_next = l;
321 	}
322 }
323 
324 static void
325 link_elf_delete_gdb(struct link_map *l)
326 {
327 	if (l->l_prev == NULL) {
328 		/* Remove first. */
329 		if ((r_debug.r_map = l->l_next) != NULL)
330 			l->l_next->l_prev = NULL;
331 	} else {
332 		/* Remove any but first. */
333 		if ((l->l_prev->l_next = l->l_next) != NULL)
334 			l->l_next->l_prev = l->l_prev;
335 	}
336 }
337 #endif /* GDB */
338 
339 /*
340  * The kernel symbol table starts here.
341  */
342 extern struct _dynamic _DYNAMIC;
343 
344 static void
345 link_elf_error(const char *filename, const char *s)
346 {
347 	if (filename == NULL)
348 		printf("kldload: %s\n", s);
349 	else
350 		printf("kldload: %s: %s\n", filename, s);
351 }
352 
353 static void
354 link_elf_invoke_ctors(caddr_t addr, size_t size)
355 {
356 	void (**ctor)(void);
357 	size_t i, cnt;
358 
359 	if (addr == NULL || size == 0)
360 		return;
361 	cnt = size / sizeof(*ctor);
362 	ctor = (void *)addr;
363 	for (i = 0; i < cnt; i++) {
364 		if (ctor[i] != NULL)
365 			(*ctor[i])();
366 	}
367 }
368 
369 /*
370  * Actions performed after linking/loading both the preloaded kernel and any
371  * modules; whether preloaded or dynamicly loaded.
372  */
373 static int
374 link_elf_link_common_finish(linker_file_t lf)
375 {
376 #ifdef GDB
377 	elf_file_t ef = (elf_file_t)lf;
378 	char *newfilename;
379 #endif
380 	int error;
381 
382 	/* Notify MD code that a module is being loaded. */
383 	error = elf_cpu_load_file(lf);
384 	if (error != 0)
385 		return (error);
386 
387 #ifdef GDB
388 	GDB_STATE(RT_ADD);
389 	ef->gdb.l_addr = lf->address;
390 	newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
391 	strcpy(newfilename, lf->filename);
392 	ef->gdb.l_name = newfilename;
393 	ef->gdb.l_ld = ef->dynamic;
394 	link_elf_add_gdb(&ef->gdb);
395 	GDB_STATE(RT_CONSISTENT);
396 #endif
397 
398 	/* Invoke .ctors */
399 	link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
400 	return (0);
401 }
402 
403 #ifdef RELOCATABLE_KERNEL
404 /*
405  * __startkernel and __endkernel are symbols set up as relocation canaries.
406  *
407  * They are defined in locore to reference linker script symbols at the
408  * beginning and end of the LOAD area. This has the desired side effect of
409  * giving us variables that have relative relocations pointing at them, so
410  * relocation of the kernel object will cause the variables to be updated
411  * automatically by the runtime linker when we initialize.
412  *
413  * There are two main reasons to relocate the kernel:
414  * 1) If the loader needed to load the kernel at an alternate load address.
415  * 2) If the kernel is switching address spaces on machines like POWER9
416  *    under Radix where the high bits of the effective address are used to
417  *    differentiate between hypervisor, host, guest, and problem state.
418  */
419 extern vm_offset_t __startkernel, __endkernel;
420 #endif
421 
422 static unsigned long kern_relbase = KERNBASE;
423 
424 SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD,
425 	SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address");
426 SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD,
427 	&kern_relbase, 0, "Kernel relocated base address");
428 
429 static void
430 link_elf_init(void* arg)
431 {
432 	Elf_Dyn *dp;
433 	Elf_Addr *ctors_addrp;
434 	Elf_Size *ctors_sizep;
435 	caddr_t modptr, baseptr, sizeptr;
436 	elf_file_t ef;
437 	const char *modname;
438 
439 	linker_add_class(&link_elf_class);
440 
441 	dp = (Elf_Dyn *)&_DYNAMIC;
442 	modname = NULL;
443 	modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
444 	if (modptr == NULL)
445 		modptr = preload_search_by_type("elf kernel");
446 	modname = (char *)preload_search_info(modptr, MODINFO_NAME);
447 	if (modname == NULL)
448 		modname = "kernel";
449 	linker_kernel_file = linker_make_file(modname, &link_elf_class);
450 	if (linker_kernel_file == NULL)
451 		panic("%s: Can't create linker structures for kernel",
452 		    __func__);
453 
454 	ef = (elf_file_t) linker_kernel_file;
455 	ef->preloaded = 1;
456 #ifdef RELOCATABLE_KERNEL
457 	/* Compute relative displacement */
458 	ef->address = (caddr_t) (__startkernel - KERNBASE);
459 #else
460 	ef->address = 0;
461 #endif
462 #ifdef SPARSE_MAPPING
463 	ef->object = NULL;
464 #endif
465 	ef->dynamic = dp;
466 
467 	if (dp != NULL)
468 		parse_dynamic(ef);
469 #ifdef RELOCATABLE_KERNEL
470 	linker_kernel_file->address = (caddr_t)__startkernel;
471 	linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
472 	kern_relbase = (unsigned long)__startkernel;
473 #else
474 	linker_kernel_file->address += KERNBASE;
475 	linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
476 #endif
477 
478 	if (modptr != NULL) {
479 		ef->modptr = modptr;
480 		baseptr = preload_search_info(modptr, MODINFO_ADDR);
481 		if (baseptr != NULL)
482 			linker_kernel_file->address = *(caddr_t *)baseptr;
483 		sizeptr = preload_search_info(modptr, MODINFO_SIZE);
484 		if (sizeptr != NULL)
485 			linker_kernel_file->size = *(size_t *)sizeptr;
486 		ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
487 			MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
488 		ctors_sizep = (Elf_Size *)preload_search_info(modptr,
489 			MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
490 		if (ctors_addrp != NULL && ctors_sizep != NULL) {
491 			linker_kernel_file->ctors_addr = ef->address +
492 			    *ctors_addrp;
493 			linker_kernel_file->ctors_size = *ctors_sizep;
494 		}
495 	}
496 	(void)link_elf_preload_parse_symbols(ef);
497 
498 #ifdef GDB
499 	r_debug.r_map = NULL;
500 	r_debug.r_brk = r_debug_state;
501 	r_debug.r_state = RT_CONSISTENT;
502 #endif
503 
504 	(void)link_elf_link_common_finish(linker_kernel_file);
505 	linker_kernel_file->flags |= LINKER_FILE_LINKED;
506 	TAILQ_INIT(&set_pcpu_list);
507 #ifdef VIMAGE
508 	TAILQ_INIT(&set_vnet_list);
509 	vnet_save_init((void *)VNET_START, VNET_STOP - VNET_START);
510 #endif
511 }
512 
513 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL);
514 
515 static int
516 link_elf_preload_parse_symbols(elf_file_t ef)
517 {
518 	caddr_t pointer;
519 	caddr_t ssym, esym, base;
520 	caddr_t strtab;
521 	int strcnt;
522 	Elf_Sym *symtab;
523 	int symcnt;
524 
525 	if (ef->modptr == NULL)
526 		return (0);
527 	pointer = preload_search_info(ef->modptr,
528 	    MODINFO_METADATA | MODINFOMD_SSYM);
529 	if (pointer == NULL)
530 		return (0);
531 	ssym = *(caddr_t *)pointer;
532 	pointer = preload_search_info(ef->modptr,
533 	    MODINFO_METADATA | MODINFOMD_ESYM);
534 	if (pointer == NULL)
535 		return (0);
536 	esym = *(caddr_t *)pointer;
537 
538 	base = ssym;
539 
540 	symcnt = *(long *)base;
541 	base += sizeof(long);
542 	symtab = (Elf_Sym *)base;
543 	base += roundup(symcnt, sizeof(long));
544 
545 	if (base > esym || base < ssym) {
546 		printf("Symbols are corrupt!\n");
547 		return (EINVAL);
548 	}
549 
550 	strcnt = *(long *)base;
551 	base += sizeof(long);
552 	strtab = base;
553 	base += roundup(strcnt, sizeof(long));
554 
555 	if (base > esym || base < ssym) {
556 		printf("Symbols are corrupt!\n");
557 		return (EINVAL);
558 	}
559 
560 	ef->ddbsymtab = symtab;
561 	ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
562 	ef->ddbstrtab = strtab;
563 	ef->ddbstrcnt = strcnt;
564 
565 	return (0);
566 }
567 
568 static int
569 parse_dynamic(elf_file_t ef)
570 {
571 	Elf_Dyn *dp;
572 	int plttype = DT_REL;
573 
574 	for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
575 		switch (dp->d_tag) {
576 		case DT_HASH:
577 		{
578 			/* From src/libexec/rtld-elf/rtld.c */
579 			const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
580 			    (ef->address + dp->d_un.d_ptr);
581 			ef->nbuckets = hashtab[0];
582 			ef->nchains = hashtab[1];
583 			ef->buckets = hashtab + 2;
584 			ef->chains = ef->buckets + ef->nbuckets;
585 			break;
586 		}
587 		case DT_STRTAB:
588 			ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
589 			break;
590 		case DT_STRSZ:
591 			ef->strsz = dp->d_un.d_val;
592 			break;
593 		case DT_SYMTAB:
594 			ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
595 			break;
596 		case DT_SYMENT:
597 			if (dp->d_un.d_val != sizeof(Elf_Sym))
598 				return (ENOEXEC);
599 			break;
600 		case DT_PLTGOT:
601 			ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
602 			break;
603 		case DT_REL:
604 			ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
605 			break;
606 		case DT_RELSZ:
607 			ef->relsize = dp->d_un.d_val;
608 			break;
609 		case DT_RELENT:
610 			if (dp->d_un.d_val != sizeof(Elf_Rel))
611 				return (ENOEXEC);
612 			break;
613 		case DT_JMPREL:
614 			ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
615 			break;
616 		case DT_PLTRELSZ:
617 			ef->pltrelsize = dp->d_un.d_val;
618 			break;
619 		case DT_RELA:
620 			ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
621 			break;
622 		case DT_RELASZ:
623 			ef->relasize = dp->d_un.d_val;
624 			break;
625 		case DT_RELAENT:
626 			if (dp->d_un.d_val != sizeof(Elf_Rela))
627 				return (ENOEXEC);
628 			break;
629 		case DT_PLTREL:
630 			plttype = dp->d_un.d_val;
631 			if (plttype != DT_REL && plttype != DT_RELA)
632 				return (ENOEXEC);
633 			break;
634 #ifdef GDB
635 		case DT_DEBUG:
636 			dp->d_un.d_ptr = (Elf_Addr)&r_debug;
637 			break;
638 #endif
639 		}
640 	}
641 
642 	if (plttype == DT_RELA) {
643 		ef->pltrela = (const Elf_Rela *)ef->pltrel;
644 		ef->pltrel = NULL;
645 		ef->pltrelasize = ef->pltrelsize;
646 		ef->pltrelsize = 0;
647 	}
648 
649 	ef->ddbsymtab = ef->symtab;
650 	ef->ddbsymcnt = ef->nchains;
651 	ef->ddbstrtab = ef->strtab;
652 	ef->ddbstrcnt = ef->strsz;
653 
654 	return elf_cpu_parse_dynamic(ef->address, ef->dynamic);
655 }
656 
657 #define	LS_PADDING	0x90909090
658 static int
659 parse_dpcpu(elf_file_t ef)
660 {
661 	int error, size;
662 #if defined(__i386__)
663 	uint32_t pad;
664 #endif
665 
666 	ef->pcpu_start = 0;
667 	ef->pcpu_stop = 0;
668 	error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
669 	    (void ***)&ef->pcpu_stop, NULL);
670 	/* Error just means there is no pcpu set to relocate. */
671 	if (error != 0)
672 		return (0);
673 	size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start;
674 	/* Empty set? */
675 	if (size < 1)
676 		return (0);
677 #if defined(__i386__)
678 	/* In case we do find __start/stop_set_ symbols double-check. */
679 	if (size < 4) {
680 		uprintf("Kernel module '%s' must be recompiled with "
681 		    "linker script\n", ef->lf.pathname);
682 		return (ENOEXEC);
683 	}
684 
685 	/* Padding from linker-script correct? */
686 	pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad));
687 	if (pad != LS_PADDING) {
688 		uprintf("Kernel module '%s' must be recompiled with "
689 		    "linker script, invalid padding %#04x (%#04x)\n",
690 		    ef->lf.pathname, pad, LS_PADDING);
691 		return (ENOEXEC);
692 	}
693 	/* If we only have valid padding, nothing to do. */
694 	if (size == 4)
695 		return (0);
696 #endif
697 	/*
698 	 * Allocate space in the primary pcpu area.  Copy in our
699 	 * initialization from the data section and then initialize
700 	 * all per-cpu storage from that.
701 	 */
702 	ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size);
703 	if (ef->pcpu_base == 0) {
704 		printf("%s: pcpu module space is out of space; "
705 		    "cannot allocate %d for %s\n",
706 		    __func__, size, ef->lf.pathname);
707 		return (ENOSPC);
708 	}
709 	memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size);
710 	dpcpu_copy((void *)ef->pcpu_base, size);
711 	elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
712 	    ef->pcpu_base);
713 
714 	return (0);
715 }
716 
717 #ifdef VIMAGE
718 static int
719 parse_vnet(elf_file_t ef)
720 {
721 	int error, size;
722 #if defined(__i386__)
723 	uint32_t pad;
724 #endif
725 
726 	ef->vnet_start = 0;
727 	ef->vnet_stop = 0;
728 	ef->vnet_base = 0;
729 	error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
730 	    (void ***)&ef->vnet_stop, NULL);
731 	/* Error just means there is no vnet data set to relocate. */
732 	if (error != 0)
733 		return (0);
734 	size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
735 	/* Empty set? */
736 	if (size < 1)
737 		return (0);
738 #if defined(__i386__)
739 	/* In case we do find __start/stop_set_ symbols double-check. */
740 	if (size < 4) {
741 		uprintf("Kernel module '%s' must be recompiled with "
742 		    "linker script\n", ef->lf.pathname);
743 		return (ENOEXEC);
744 	}
745 
746 	/* Padding from linker-script correct? */
747 	pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad));
748 	if (pad != LS_PADDING) {
749 		uprintf("Kernel module '%s' must be recompiled with "
750 		    "linker script, invalid padding %#04x (%#04x)\n",
751 		    ef->lf.pathname, pad, LS_PADDING);
752 		return (ENOEXEC);
753 	}
754 	/* If we only have valid padding, nothing to do. */
755 	if (size == 4)
756 		return (0);
757 #endif
758 	/*
759 	 * Allocate space in the primary vnet area.  Copy in our
760 	 * initialization from the data section and then initialize
761 	 * all per-vnet storage from that.
762 	 */
763 	ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size);
764 	if (ef->vnet_base == 0) {
765 		printf("%s: vnet module space is out of space; "
766 		    "cannot allocate %d for %s\n",
767 		    __func__, size, ef->lf.pathname);
768 		return (ENOSPC);
769 	}
770 	memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size);
771 	vnet_save_init((void *)ef->vnet_base, size);
772 	elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
773 	    ef->vnet_base);
774 
775 	return (0);
776 }
777 #endif
778 #undef LS_PADDING
779 
780 /*
781  * Apply the specified protection to the loadable segments of a preloaded linker
782  * file.
783  */
784 static int
785 preload_protect(elf_file_t ef, vm_prot_t prot)
786 {
787 #if defined(__aarch64__) || defined(__amd64__)
788 	Elf_Ehdr *hdr;
789 	Elf_Phdr *phdr, *phlimit;
790 	vm_prot_t nprot;
791 	int error;
792 
793 	error = 0;
794 	hdr = (Elf_Ehdr *)ef->address;
795 	phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff);
796 	phlimit = phdr + hdr->e_phnum;
797 	for (; phdr < phlimit; phdr++) {
798 		if (phdr->p_type != PT_LOAD)
799 			continue;
800 
801 		nprot = prot | VM_PROT_READ;
802 		if ((phdr->p_flags & PF_W) != 0)
803 			nprot |= VM_PROT_WRITE;
804 		if ((phdr->p_flags & PF_X) != 0)
805 			nprot |= VM_PROT_EXECUTE;
806 		error = pmap_change_prot((vm_offset_t)ef->address +
807 		    phdr->p_vaddr, round_page(phdr->p_memsz), nprot);
808 		if (error != 0)
809 			break;
810 	}
811 	return (error);
812 #else
813 	return (0);
814 #endif
815 }
816 
817 #ifdef __arm__
818 /*
819  * Locate the ARM exception/unwind table info for DDB and stack(9) use by
820  * searching for the section header that describes it.  There may be no unwind
821  * info, for example in a module containing only data.
822  */
823 static void
824 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr)
825 {
826 	int i;
827 
828 	for (i = 0; i < nhdr; i++) {
829 		if (shdr[i].sh_type == SHT_ARM_EXIDX) {
830 			lf->exidx_addr = shdr[i].sh_addr + lf->address;
831 			lf->exidx_size = shdr[i].sh_size;
832 			break;
833 		}
834 	}
835 }
836 
837 /*
838  * Locate the section headers metadata in a preloaded module, then use it to
839  * locate the exception/unwind table in the module.  The size of the metadata
840  * block is stored in a uint32 word immediately before the data itself, and a
841  * comment in preload_search_info() says it is safe to rely on that.
842  */
843 static void
844 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr)
845 {
846 	uint32_t *modinfo;
847 	Elf_Shdr *shdr;
848 	uint32_t  nhdr;
849 
850 	modinfo = (uint32_t *)preload_search_info(modptr,
851 	    MODINFO_METADATA | MODINFOMD_SHDR);
852 	if (modinfo != NULL) {
853 		shdr = (Elf_Shdr *)modinfo;
854 		nhdr = modinfo[-1] / sizeof(Elf_Shdr);
855 		link_elf_locate_exidx(lf, shdr, nhdr);
856 	}
857 }
858 
859 #endif /* __arm__ */
860 
861 static int
862 link_elf_link_preload(linker_class_t cls, const char *filename,
863     linker_file_t *result)
864 {
865 	Elf_Addr *ctors_addrp;
866 	Elf_Size *ctors_sizep;
867 	caddr_t modptr, baseptr, sizeptr, dynptr;
868 	char *type;
869 	elf_file_t ef;
870 	linker_file_t lf;
871 	int error;
872 	vm_offset_t dp;
873 
874 	/* Look to see if we have the file preloaded */
875 	modptr = preload_search_by_name(filename);
876 	if (modptr == NULL)
877 		return (ENOENT);
878 
879 	type = (char *)preload_search_info(modptr, MODINFO_TYPE);
880 	baseptr = preload_search_info(modptr, MODINFO_ADDR);
881 	sizeptr = preload_search_info(modptr, MODINFO_SIZE);
882 	dynptr = preload_search_info(modptr,
883 	    MODINFO_METADATA | MODINFOMD_DYNAMIC);
884 	if (type == NULL ||
885 	    (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
886 	     strcmp(type, "elf module") != 0))
887 		return (EFTYPE);
888 	if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
889 		return (EINVAL);
890 
891 	lf = linker_make_file(filename, &link_elf_class);
892 	if (lf == NULL)
893 		return (ENOMEM);
894 
895 	ef = (elf_file_t) lf;
896 	ef->preloaded = 1;
897 	ef->modptr = modptr;
898 	ef->address = *(caddr_t *)baseptr;
899 #ifdef SPARSE_MAPPING
900 	ef->object = NULL;
901 #endif
902 	dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
903 	ef->dynamic = (Elf_Dyn *)dp;
904 	lf->address = ef->address;
905 	lf->size = *(size_t *)sizeptr;
906 
907 	ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
908 	    MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
909 	ctors_sizep = (Elf_Size *)preload_search_info(modptr,
910 	    MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
911 	if (ctors_addrp != NULL && ctors_sizep != NULL) {
912 		lf->ctors_addr = ef->address + *ctors_addrp;
913 		lf->ctors_size = *ctors_sizep;
914 	}
915 
916 #ifdef __arm__
917 	link_elf_locate_exidx_preload(lf, modptr);
918 #endif
919 
920 	error = parse_dynamic(ef);
921 	if (error == 0)
922 		error = parse_dpcpu(ef);
923 #ifdef VIMAGE
924 	if (error == 0)
925 		error = parse_vnet(ef);
926 #endif
927 	if (error == 0)
928 		error = preload_protect(ef, VM_PROT_ALL);
929 	if (error != 0) {
930 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
931 		return (error);
932 	}
933 	link_elf_reloc_local(lf);
934 	*result = lf;
935 	return (0);
936 }
937 
938 static int
939 link_elf_link_preload_finish(linker_file_t lf)
940 {
941 	elf_file_t ef;
942 	int error;
943 
944 	ef = (elf_file_t) lf;
945 	error = relocate_file(ef);
946 	if (error == 0)
947 		error = preload_protect(ef, VM_PROT_NONE);
948 	if (error != 0)
949 		return (error);
950 	(void)link_elf_preload_parse_symbols(ef);
951 
952 	return (link_elf_link_common_finish(lf));
953 }
954 
955 static int
956 link_elf_load_file(linker_class_t cls, const char* filename,
957     linker_file_t* result)
958 {
959 	struct nameidata nd;
960 	struct thread* td = curthread;	/* XXX */
961 	Elf_Ehdr *hdr;
962 	caddr_t firstpage, segbase;
963 	int nbytes, i;
964 	Elf_Phdr *phdr;
965 	Elf_Phdr *phlimit;
966 	Elf_Phdr *segs[MAXSEGS];
967 	int nsegs;
968 	Elf_Phdr *phdyn;
969 	caddr_t mapbase;
970 	size_t mapsize;
971 	Elf_Addr base_vaddr;
972 	Elf_Addr base_vlimit;
973 	int error = 0;
974 	ssize_t resid;
975 	int flags;
976 	elf_file_t ef;
977 	linker_file_t lf;
978 	Elf_Shdr *shdr;
979 	int symtabindex;
980 	int symstrindex;
981 	int shstrindex;
982 	int symcnt;
983 	int strcnt;
984 	char *shstrs;
985 
986 	shdr = NULL;
987 	lf = NULL;
988 	shstrs = NULL;
989 
990 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename);
991 	flags = FREAD;
992 	error = vn_open(&nd, &flags, 0, NULL);
993 	if (error != 0)
994 		return (error);
995 	NDFREE_PNBUF(&nd);
996 	if (nd.ni_vp->v_type != VREG) {
997 		error = ENOEXEC;
998 		firstpage = NULL;
999 		goto out;
1000 	}
1001 #ifdef MAC
1002 	error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
1003 	if (error != 0) {
1004 		firstpage = NULL;
1005 		goto out;
1006 	}
1007 #endif
1008 
1009 	/*
1010 	 * Read the elf header from the file.
1011 	 */
1012 	firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
1013 	hdr = (Elf_Ehdr *)firstpage;
1014 	error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
1015 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1016 	    &resid, td);
1017 	nbytes = PAGE_SIZE - resid;
1018 	if (error != 0)
1019 		goto out;
1020 
1021 	if (!IS_ELF(*hdr)) {
1022 		error = ENOEXEC;
1023 		goto out;
1024 	}
1025 
1026 	if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
1027 	    hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
1028 		link_elf_error(filename, "Unsupported file layout");
1029 		error = ENOEXEC;
1030 		goto out;
1031 	}
1032 	if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
1033 	    hdr->e_version != EV_CURRENT) {
1034 		link_elf_error(filename, "Unsupported file version");
1035 		error = ENOEXEC;
1036 		goto out;
1037 	}
1038 	if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
1039 		error = ENOSYS;
1040 		goto out;
1041 	}
1042 	if (hdr->e_machine != ELF_TARG_MACH) {
1043 		link_elf_error(filename, "Unsupported machine");
1044 		error = ENOEXEC;
1045 		goto out;
1046 	}
1047 
1048 	/*
1049 	 * We rely on the program header being in the first page.
1050 	 * This is not strictly required by the ABI specification, but
1051 	 * it seems to always true in practice.  And, it simplifies
1052 	 * things considerably.
1053 	 */
1054 	if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
1055 	      (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
1056 	      (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
1057 		link_elf_error(filename, "Unreadable program headers");
1058 
1059 	/*
1060 	 * Scan the program header entries, and save key information.
1061 	 *
1062 	 * We rely on there being exactly two load segments, text and data,
1063 	 * in that order.
1064 	 */
1065 	phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
1066 	phlimit = phdr + hdr->e_phnum;
1067 	nsegs = 0;
1068 	phdyn = NULL;
1069 	while (phdr < phlimit) {
1070 		switch (phdr->p_type) {
1071 		case PT_LOAD:
1072 			if (nsegs == MAXSEGS) {
1073 				link_elf_error(filename, "Too many sections");
1074 				error = ENOEXEC;
1075 				goto out;
1076 			}
1077 			/*
1078 			 * XXX: We just trust they come in right order ??
1079 			 */
1080 			segs[nsegs] = phdr;
1081 			++nsegs;
1082 			break;
1083 
1084 		case PT_DYNAMIC:
1085 			phdyn = phdr;
1086 			break;
1087 
1088 		case PT_INTERP:
1089 			error = ENOSYS;
1090 			goto out;
1091 		}
1092 
1093 		++phdr;
1094 	}
1095 	if (phdyn == NULL) {
1096 		link_elf_error(filename, "Object is not dynamically-linked");
1097 		error = ENOEXEC;
1098 		goto out;
1099 	}
1100 	if (nsegs == 0) {
1101 		link_elf_error(filename, "No sections");
1102 		error = ENOEXEC;
1103 		goto out;
1104 	}
1105 
1106 	/*
1107 	 * Allocate the entire address space of the object, to stake
1108 	 * out our contiguous region, and to establish the base
1109 	 * address for relocation.
1110 	 */
1111 	base_vaddr = trunc_page(segs[0]->p_vaddr);
1112 	base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
1113 	    segs[nsegs - 1]->p_memsz);
1114 	mapsize = base_vlimit - base_vaddr;
1115 
1116 	lf = linker_make_file(filename, &link_elf_class);
1117 	if (lf == NULL) {
1118 		error = ENOMEM;
1119 		goto out;
1120 	}
1121 
1122 	ef = (elf_file_t) lf;
1123 #ifdef SPARSE_MAPPING
1124 	ef->object = vm_pager_allocate(OBJT_PHYS, NULL, mapsize, VM_PROT_ALL,
1125 	    0, thread0.td_ucred);
1126 	if (ef->object == NULL) {
1127 		error = ENOMEM;
1128 		goto out;
1129 	}
1130 #ifdef __amd64__
1131 	mapbase = (caddr_t)KERNBASE;
1132 #else
1133 	mapbase = (caddr_t)vm_map_min(kernel_map);
1134 #endif
1135 	/*
1136 	 * Mapping protections are downgraded after relocation processing.
1137 	 */
1138 	error = vm_map_find(kernel_map, ef->object, 0,
1139 	    (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE,
1140 	    VM_PROT_ALL, VM_PROT_ALL, 0);
1141 	if (error != 0) {
1142 		vm_object_deallocate(ef->object);
1143 		ef->object = NULL;
1144 		goto out;
1145 	}
1146 #else
1147 	mapbase = malloc_exec(mapsize, M_LINKER, M_WAITOK);
1148 #endif
1149 	ef->address = mapbase;
1150 
1151 	/*
1152 	 * Read the text and data sections and zero the bss.
1153 	 */
1154 	for (i = 0; i < nsegs; i++) {
1155 		segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1156 
1157 #ifdef SPARSE_MAPPING
1158 		/*
1159 		 * Consecutive segments may have different mapping permissions,
1160 		 * so be strict and verify that their mappings do not overlap.
1161 		 */
1162 		if (((vm_offset_t)segbase & PAGE_MASK) != 0) {
1163 			error = EINVAL;
1164 			goto out;
1165 		}
1166 
1167 		error = vm_map_wire(kernel_map,
1168 		    (vm_offset_t)segbase,
1169 		    (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1170 		    VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
1171 		if (error != KERN_SUCCESS) {
1172 			error = ENOMEM;
1173 			goto out;
1174 		}
1175 #endif
1176 
1177 		error = vn_rdwr(UIO_READ, nd.ni_vp,
1178 		    segbase, segs[i]->p_filesz, segs[i]->p_offset,
1179 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1180 		    &resid, td);
1181 		if (error != 0)
1182 			goto out;
1183 		bzero(segbase + segs[i]->p_filesz,
1184 		    segs[i]->p_memsz - segs[i]->p_filesz);
1185 	}
1186 
1187 	ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
1188 
1189 	lf->address = ef->address;
1190 	lf->size = mapsize;
1191 
1192 	error = parse_dynamic(ef);
1193 	if (error != 0)
1194 		goto out;
1195 	error = parse_dpcpu(ef);
1196 	if (error != 0)
1197 		goto out;
1198 #ifdef VIMAGE
1199 	error = parse_vnet(ef);
1200 	if (error != 0)
1201 		goto out;
1202 #endif
1203 	link_elf_reloc_local(lf);
1204 
1205 	VOP_UNLOCK(nd.ni_vp);
1206 	error = linker_load_dependencies(lf);
1207 	vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1208 	if (error != 0)
1209 		goto out;
1210 	error = relocate_file(ef);
1211 	if (error != 0)
1212 		goto out;
1213 
1214 #ifdef SPARSE_MAPPING
1215 	/*
1216 	 * Downgrade permissions on text segment mappings now that relocation
1217 	 * processing is complete.  Restrict permissions on read-only segments.
1218 	 */
1219 	for (i = 0; i < nsegs; i++) {
1220 		vm_prot_t prot;
1221 
1222 		if (segs[i]->p_type != PT_LOAD)
1223 			continue;
1224 
1225 		prot = VM_PROT_READ;
1226 		if ((segs[i]->p_flags & PF_W) != 0)
1227 			prot |= VM_PROT_WRITE;
1228 		if ((segs[i]->p_flags & PF_X) != 0)
1229 			prot |= VM_PROT_EXECUTE;
1230 		segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1231 		error = vm_map_protect(kernel_map,
1232 		    (vm_offset_t)segbase,
1233 		    (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1234 		    prot, 0, VM_MAP_PROTECT_SET_PROT);
1235 		if (error != KERN_SUCCESS) {
1236 			error = ENOMEM;
1237 			goto out;
1238 		}
1239 	}
1240 #endif
1241 
1242 	/*
1243 	 * Try and load the symbol table if it's present.  (you can
1244 	 * strip it!)
1245 	 */
1246 	nbytes = hdr->e_shnum * hdr->e_shentsize;
1247 	if (nbytes == 0 || hdr->e_shoff == 0)
1248 		goto nosyms;
1249 	shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1250 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1251 	    (caddr_t)shdr, nbytes, hdr->e_shoff,
1252 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1253 	    &resid, td);
1254 	if (error != 0)
1255 		goto out;
1256 
1257 	/* Read section string table */
1258 	shstrindex = hdr->e_shstrndx;
1259 	if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1260 	    shdr[shstrindex].sh_size != 0) {
1261 		nbytes = shdr[shstrindex].sh_size;
1262 		shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1263 		error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1264 		    shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1265 		    td->td_ucred, NOCRED, &resid, td);
1266 		if (error)
1267 			goto out;
1268 	}
1269 
1270 	symtabindex = -1;
1271 	symstrindex = -1;
1272 	for (i = 0; i < hdr->e_shnum; i++) {
1273 		if (shdr[i].sh_type == SHT_SYMTAB) {
1274 			symtabindex = i;
1275 			symstrindex = shdr[i].sh_link;
1276 		} else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1277 		    strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1278 			/* Record relocated address and size of .ctors. */
1279 			lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1280 			lf->ctors_size = shdr[i].sh_size;
1281 		}
1282 	}
1283 	if (symtabindex < 0 || symstrindex < 0)
1284 		goto nosyms;
1285 
1286 	symcnt = shdr[symtabindex].sh_size;
1287 	ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1288 	strcnt = shdr[symstrindex].sh_size;
1289 	ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1290 
1291 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1292 	    ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1293 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1294 	    &resid, td);
1295 	if (error != 0)
1296 		goto out;
1297 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1298 	    ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1299 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1300 	    &resid, td);
1301 	if (error != 0)
1302 		goto out;
1303 
1304 	ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1305 	ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1306 	ef->ddbstrcnt = strcnt;
1307 	ef->ddbstrtab = ef->strbase;
1308 
1309 nosyms:
1310 
1311 #ifdef __arm__
1312 	link_elf_locate_exidx(lf, shdr, hdr->e_shnum);
1313 #endif
1314 
1315 	error = link_elf_link_common_finish(lf);
1316 	if (error != 0)
1317 		goto out;
1318 
1319 	*result = lf;
1320 
1321 out:
1322 	VOP_UNLOCK(nd.ni_vp);
1323 	vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1324 	if (error != 0 && lf != NULL)
1325 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1326 	free(shdr, M_LINKER);
1327 	free(firstpage, M_LINKER);
1328 	free(shstrs, M_LINKER);
1329 
1330 	return (error);
1331 }
1332 
1333 Elf_Addr
1334 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1335 {
1336 	elf_file_t ef;
1337 
1338 	KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class,
1339 	    ("elf_relocaddr: unexpected linker file %p", lf));
1340 
1341 	ef = (elf_file_t)lf;
1342 	if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1343 		return ((x - ef->pcpu_start) + ef->pcpu_base);
1344 #ifdef VIMAGE
1345 	if (x >= ef->vnet_start && x < ef->vnet_stop)
1346 		return ((x - ef->vnet_start) + ef->vnet_base);
1347 #endif
1348 	return (x);
1349 }
1350 
1351 static void
1352 link_elf_unload_file(linker_file_t file)
1353 {
1354 	elf_file_t ef = (elf_file_t) file;
1355 
1356 	if (ef->pcpu_base != 0) {
1357 		dpcpu_free((void *)ef->pcpu_base,
1358 		    ef->pcpu_stop - ef->pcpu_start);
1359 		elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1360 	}
1361 #ifdef VIMAGE
1362 	if (ef->vnet_base != 0) {
1363 		vnet_data_free((void *)ef->vnet_base,
1364 		    ef->vnet_stop - ef->vnet_start);
1365 		elf_set_delete(&set_vnet_list, ef->vnet_start);
1366 	}
1367 #endif
1368 #ifdef GDB
1369 	if (ef->gdb.l_ld != NULL) {
1370 		GDB_STATE(RT_DELETE);
1371 		free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1372 		link_elf_delete_gdb(&ef->gdb);
1373 		GDB_STATE(RT_CONSISTENT);
1374 	}
1375 #endif
1376 
1377 	/* Notify MD code that a module is being unloaded. */
1378 	elf_cpu_unload_file(file);
1379 
1380 	if (ef->preloaded) {
1381 		link_elf_unload_preload(file);
1382 		return;
1383 	}
1384 
1385 #ifdef SPARSE_MAPPING
1386 	if (ef->object != NULL) {
1387 		vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1388 		    (vm_offset_t) ef->address
1389 		    + (ef->object->size << PAGE_SHIFT));
1390 	}
1391 #else
1392 	free(ef->address, M_LINKER);
1393 #endif
1394 	free(ef->symbase, M_LINKER);
1395 	free(ef->strbase, M_LINKER);
1396 	free(ef->ctftab, M_LINKER);
1397 	free(ef->ctfoff, M_LINKER);
1398 	free(ef->typoff, M_LINKER);
1399 }
1400 
1401 static void
1402 link_elf_unload_preload(linker_file_t file)
1403 {
1404 
1405 	if (file->pathname != NULL)
1406 		preload_delete_name(file->pathname);
1407 }
1408 
1409 static const char *
1410 symbol_name(elf_file_t ef, Elf_Size r_info)
1411 {
1412 	const Elf_Sym *ref;
1413 
1414 	if (ELF_R_SYM(r_info)) {
1415 		ref = ef->symtab + ELF_R_SYM(r_info);
1416 		return (ef->strtab + ref->st_name);
1417 	}
1418 	return (NULL);
1419 }
1420 
1421 static int
1422 symbol_type(elf_file_t ef, Elf_Size r_info)
1423 {
1424 	const Elf_Sym *ref;
1425 
1426 	if (ELF_R_SYM(r_info)) {
1427 		ref = ef->symtab + ELF_R_SYM(r_info);
1428 		return (ELF_ST_TYPE(ref->st_info));
1429 	}
1430 	return (STT_NOTYPE);
1431 }
1432 
1433 static int
1434 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc,
1435     bool ifuncs)
1436 {
1437 	const Elf_Rel *rel;
1438 	const Elf_Rela *rela;
1439 	const char *symname;
1440 
1441 	TSENTER();
1442 #define	APPLY_RELOCS(iter, tbl, tblsize, type) do {			\
1443 	for ((iter) = (tbl); (iter) != NULL &&				\
1444 	    (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) {	\
1445 		if ((symbol_type(ef, (iter)->r_info) ==			\
1446 		    STT_GNU_IFUNC ||					\
1447 		    elf_is_ifunc_reloc((iter)->r_info)) != ifuncs)	\
1448 			continue;					\
1449 		if (reloc(&ef->lf, (Elf_Addr)ef->address,		\
1450 		    (iter), (type), lookup)) {				\
1451 			symname = symbol_name(ef, (iter)->r_info);	\
1452 			printf("link_elf: symbol %s undefined\n",	\
1453 			    symname);					\
1454 			return (ENOENT);				\
1455 		}							\
1456 	}								\
1457 } while (0)
1458 
1459 	APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL);
1460 	TSENTER2("ef->rela");
1461 	APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA);
1462 	TSEXIT2("ef->rela");
1463 	APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL);
1464 	APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA);
1465 
1466 #undef APPLY_RELOCS
1467 
1468 	TSEXIT();
1469 	return (0);
1470 }
1471 
1472 static int
1473 relocate_file(elf_file_t ef)
1474 {
1475 	int error;
1476 
1477 	error = relocate_file1(ef, elf_lookup, elf_reloc, false);
1478 	if (error == 0)
1479 		error = relocate_file1(ef, elf_lookup, elf_reloc, true);
1480 	return (error);
1481 }
1482 
1483 /*
1484  * SysV hash function for symbol table lookup.  It is specified by the
1485  * System V ABI.
1486  */
1487 static Elf32_Word
1488 elf_hash(const char *name)
1489 {
1490 	const unsigned char *p = (const unsigned char *)name;
1491 	Elf32_Word h = 0;
1492 
1493 	while (*p != '\0') {
1494 		h = (h << 4) + *p++;
1495 		h ^= (h >> 24) & 0xf0;
1496 	}
1497 	return (h & 0x0fffffff);
1498 }
1499 
1500 static int
1501 link_elf_lookup_symbol1(linker_file_t lf, const char *name, c_linker_sym_t *sym,
1502     bool see_local)
1503 {
1504 	elf_file_t ef = (elf_file_t) lf;
1505 	unsigned long symnum;
1506 	const Elf_Sym* symp;
1507 	const char *strp;
1508 	Elf32_Word hash;
1509 
1510 	/* If we don't have a hash, bail. */
1511 	if (ef->buckets == NULL || ef->nbuckets == 0) {
1512 		printf("link_elf_lookup_symbol: missing symbol hash table\n");
1513 		return (ENOENT);
1514 	}
1515 
1516 	/* First, search hashed global symbols */
1517 	hash = elf_hash(name);
1518 	symnum = ef->buckets[hash % ef->nbuckets];
1519 
1520 	while (symnum != STN_UNDEF) {
1521 		if (symnum >= ef->nchains) {
1522 			printf("%s: corrupt symbol table\n", __func__);
1523 			return (ENOENT);
1524 		}
1525 
1526 		symp = ef->symtab + symnum;
1527 		if (symp->st_name == 0) {
1528 			printf("%s: corrupt symbol table\n", __func__);
1529 			return (ENOENT);
1530 		}
1531 
1532 		strp = ef->strtab + symp->st_name;
1533 
1534 		if (strcmp(name, strp) == 0) {
1535 			if (symp->st_shndx != SHN_UNDEF ||
1536 			    (symp->st_value != 0 &&
1537 			    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1538 			    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1539 				if (see_local ||
1540 				    ELF_ST_BIND(symp->st_info) != STB_LOCAL) {
1541 					*sym = (c_linker_sym_t) symp;
1542 					return (0);
1543 				}
1544 			}
1545 			return (ENOENT);
1546 		}
1547 
1548 		symnum = ef->chains[symnum];
1549 	}
1550 
1551 	return (ENOENT);
1552 }
1553 
1554 static int
1555 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1556 {
1557 	if (link_elf_leak_locals)
1558 		return (link_elf_lookup_debug_symbol(lf, name, sym));
1559 	return (link_elf_lookup_symbol1(lf, name, sym, false));
1560 }
1561 
1562 static int
1563 link_elf_lookup_debug_symbol(linker_file_t lf, const char *name,
1564     c_linker_sym_t *sym)
1565 {
1566 	elf_file_t ef = (elf_file_t)lf;
1567 	const Elf_Sym* symp;
1568 	const char *strp;
1569 	int i;
1570 
1571 	if (link_elf_lookup_symbol1(lf, name, sym, true) == 0)
1572 		return (0);
1573 
1574 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1575 		strp = ef->ddbstrtab + symp->st_name;
1576 		if (strcmp(name, strp) == 0) {
1577 			if (symp->st_shndx != SHN_UNDEF ||
1578 			    (symp->st_value != 0 &&
1579 			    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1580 			    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1581 				*sym = (c_linker_sym_t) symp;
1582 				return (0);
1583 			}
1584 			return (ENOENT);
1585 		}
1586 	}
1587 
1588 	return (ENOENT);
1589 }
1590 
1591 static int
1592 link_elf_symbol_values1(linker_file_t lf, c_linker_sym_t sym,
1593     linker_symval_t *symval, bool see_local)
1594 {
1595 	elf_file_t ef;
1596 	const Elf_Sym *es;
1597 	caddr_t val;
1598 
1599 	ef = (elf_file_t)lf;
1600 	es = (const Elf_Sym *)sym;
1601 	if (es >= ef->symtab && es < ef->symtab + ef->nchains) {
1602 		if (!see_local && ELF_ST_BIND(es->st_info) == STB_LOCAL)
1603 			return (ENOENT);
1604 		symval->name = ef->strtab + es->st_name;
1605 		val = (caddr_t)ef->address + es->st_value;
1606 		if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1607 			val = ((caddr_t (*)(void))val)();
1608 		symval->value = val;
1609 		symval->size = es->st_size;
1610 		return (0);
1611 	}
1612 	return (ENOENT);
1613 }
1614 
1615 static int
1616 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1617     linker_symval_t *symval)
1618 {
1619 	if (link_elf_leak_locals)
1620 		return (link_elf_debug_symbol_values(lf, sym, symval));
1621 	return (link_elf_symbol_values1(lf, sym, symval, false));
1622 }
1623 
1624 static int
1625 link_elf_debug_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1626     linker_symval_t *symval)
1627 {
1628 	elf_file_t ef = (elf_file_t)lf;
1629 	const Elf_Sym *es = (const Elf_Sym *)sym;
1630 	caddr_t val;
1631 
1632 	if (link_elf_symbol_values1(lf, sym, symval, true) == 0)
1633 		return (0);
1634 	if (ef->symtab == ef->ddbsymtab)
1635 		return (ENOENT);
1636 
1637 	if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1638 		symval->name = ef->ddbstrtab + es->st_name;
1639 		val = (caddr_t)ef->address + es->st_value;
1640 		if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1641 			val = ((caddr_t (*)(void))val)();
1642 		symval->value = val;
1643 		symval->size = es->st_size;
1644 		return (0);
1645 	}
1646 	return (ENOENT);
1647 }
1648 
1649 static int
1650 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1651     c_linker_sym_t *sym, long *diffp)
1652 {
1653 	elf_file_t ef = (elf_file_t)lf;
1654 	u_long off = (uintptr_t)(void *)value;
1655 	u_long diff = off;
1656 	u_long st_value;
1657 	const Elf_Sym *es;
1658 	const Elf_Sym *best = NULL;
1659 	int i;
1660 
1661 	for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1662 		if (es->st_name == 0)
1663 			continue;
1664 		st_value = es->st_value + (uintptr_t) (void *) ef->address;
1665 		if (off >= st_value) {
1666 			if (off - st_value < diff) {
1667 				diff = off - st_value;
1668 				best = es;
1669 				if (diff == 0)
1670 					break;
1671 			} else if (off - st_value == diff) {
1672 				best = es;
1673 			}
1674 		}
1675 	}
1676 	if (best == NULL)
1677 		*diffp = off;
1678 	else
1679 		*diffp = diff;
1680 	*sym = (c_linker_sym_t) best;
1681 
1682 	return (0);
1683 }
1684 
1685 /*
1686  * Look up a linker set on an ELF system.
1687  */
1688 static int
1689 link_elf_lookup_set(linker_file_t lf, const char *name,
1690     void ***startp, void ***stopp, int *countp)
1691 {
1692 	c_linker_sym_t sym;
1693 	linker_symval_t symval;
1694 	char *setsym;
1695 	void **start, **stop;
1696 	int len, error = 0, count;
1697 
1698 	len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1699 	setsym = malloc(len, M_LINKER, M_WAITOK);
1700 
1701 	/* get address of first entry */
1702 	snprintf(setsym, len, "%s%s", "__start_set_", name);
1703 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1704 	if (error != 0)
1705 		goto out;
1706 	link_elf_symbol_values(lf, sym, &symval);
1707 	if (symval.value == 0) {
1708 		error = ESRCH;
1709 		goto out;
1710 	}
1711 	start = (void **)symval.value;
1712 
1713 	/* get address of last entry */
1714 	snprintf(setsym, len, "%s%s", "__stop_set_", name);
1715 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1716 	if (error != 0)
1717 		goto out;
1718 	link_elf_symbol_values(lf, sym, &symval);
1719 	if (symval.value == 0) {
1720 		error = ESRCH;
1721 		goto out;
1722 	}
1723 	stop = (void **)symval.value;
1724 
1725 	/* and the number of entries */
1726 	count = stop - start;
1727 
1728 	/* and copy out */
1729 	if (startp != NULL)
1730 		*startp = start;
1731 	if (stopp != NULL)
1732 		*stopp = stop;
1733 	if (countp != NULL)
1734 		*countp = count;
1735 
1736 out:
1737 	free(setsym, M_LINKER);
1738 	return (error);
1739 }
1740 
1741 static int
1742 link_elf_each_function_name(linker_file_t file,
1743   int (*callback)(const char *, void *), void *opaque)
1744 {
1745 	elf_file_t ef = (elf_file_t)file;
1746 	const Elf_Sym *symp;
1747 	int i, error;
1748 
1749 	/* Exhaustive search */
1750 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1751 		if (symp->st_value != 0 &&
1752 		    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1753 		    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1754 			error = callback(ef->ddbstrtab + symp->st_name, opaque);
1755 			if (error != 0)
1756 				return (error);
1757 		}
1758 	}
1759 	return (0);
1760 }
1761 
1762 static int
1763 link_elf_each_function_nameval(linker_file_t file,
1764     linker_function_nameval_callback_t callback, void *opaque)
1765 {
1766 	linker_symval_t symval;
1767 	elf_file_t ef = (elf_file_t)file;
1768 	const Elf_Sym *symp;
1769 	int i, error;
1770 
1771 	/* Exhaustive search */
1772 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1773 		if (symp->st_value != 0 &&
1774 		    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1775 		    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1776 			error = link_elf_debug_symbol_values(file,
1777 			    (c_linker_sym_t) symp, &symval);
1778 			if (error == 0)
1779 				error = callback(file, i, &symval, opaque);
1780 			if (error != 0)
1781 				return (error);
1782 		}
1783 	}
1784 	return (0);
1785 }
1786 
1787 const Elf_Sym *
1788 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1789 {
1790 	elf_file_t ef = (elf_file_t)lf;
1791 
1792 	if (symidx >= ef->nchains)
1793 		return (NULL);
1794 	return (ef->symtab + symidx);
1795 }
1796 
1797 const char *
1798 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1799 {
1800 	elf_file_t ef = (elf_file_t)lf;
1801 	const Elf_Sym *sym;
1802 
1803 	if (symidx >= ef->nchains)
1804 		return (NULL);
1805 	sym = ef->symtab + symidx;
1806 	return (ef->strtab + sym->st_name);
1807 }
1808 
1809 /*
1810  * Symbol lookup function that can be used when the symbol index is known (ie
1811  * in relocations). It uses the symbol index instead of doing a fully fledged
1812  * hash table based lookup when such is valid. For example for local symbols.
1813  * This is not only more efficient, it's also more correct. It's not always
1814  * the case that the symbol can be found through the hash table.
1815  */
1816 static int
1817 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1818 {
1819 	elf_file_t ef = (elf_file_t)lf;
1820 	const Elf_Sym *sym;
1821 	const char *symbol;
1822 	Elf_Addr addr, start, base;
1823 
1824 	/* Don't even try to lookup the symbol if the index is bogus. */
1825 	if (symidx >= ef->nchains) {
1826 		*res = 0;
1827 		return (EINVAL);
1828 	}
1829 
1830 	sym = ef->symtab + symidx;
1831 
1832 	/*
1833 	 * Don't do a full lookup when the symbol is local. It may even
1834 	 * fail because it may not be found through the hash table.
1835 	 */
1836 	if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1837 		/* Force lookup failure when we have an insanity. */
1838 		if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1839 			*res = 0;
1840 			return (EINVAL);
1841 		}
1842 		*res = ((Elf_Addr)ef->address + sym->st_value);
1843 		return (0);
1844 	}
1845 
1846 	/*
1847 	 * XXX we can avoid doing a hash table based lookup for global
1848 	 * symbols as well. This however is not always valid, so we'll
1849 	 * just do it the hard way for now. Performance tweaks can
1850 	 * always be added.
1851 	 */
1852 
1853 	symbol = ef->strtab + sym->st_name;
1854 
1855 	/* Force a lookup failure if the symbol name is bogus. */
1856 	if (*symbol == 0) {
1857 		*res = 0;
1858 		return (EINVAL);
1859 	}
1860 
1861 	addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1862 	if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1863 		*res = 0;
1864 		return (EINVAL);
1865 	}
1866 
1867 	if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1868 		addr = addr - start + base;
1869 #ifdef VIMAGE
1870 	else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1871 		addr = addr - start + base;
1872 #endif
1873 	*res = addr;
1874 	return (0);
1875 }
1876 
1877 static void
1878 link_elf_reloc_local(linker_file_t lf)
1879 {
1880 	const Elf_Rel *rellim;
1881 	const Elf_Rel *rel;
1882 	const Elf_Rela *relalim;
1883 	const Elf_Rela *rela;
1884 	elf_file_t ef = (elf_file_t)lf;
1885 
1886 	/* Perform relocations without addend if there are any: */
1887 	if ((rel = ef->rel) != NULL) {
1888 		rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1889 		while (rel < rellim) {
1890 			elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1891 			    ELF_RELOC_REL, elf_lookup);
1892 			rel++;
1893 		}
1894 	}
1895 
1896 	/* Perform relocations with addend if there are any: */
1897 	if ((rela = ef->rela) != NULL) {
1898 		relalim = (const Elf_Rela *)
1899 		    ((const char *)ef->rela + ef->relasize);
1900 		while (rela < relalim) {
1901 			elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1902 			    ELF_RELOC_RELA, elf_lookup);
1903 			rela++;
1904 		}
1905 	}
1906 }
1907 
1908 static long
1909 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1910 {
1911 	elf_file_t ef = (elf_file_t)lf;
1912 
1913 	*symtab = ef->ddbsymtab;
1914 
1915 	if (*symtab == NULL)
1916 		return (0);
1917 
1918 	return (ef->ddbsymcnt);
1919 }
1920 
1921 static long
1922 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1923 {
1924 	elf_file_t ef = (elf_file_t)lf;
1925 
1926 	*strtab = ef->ddbstrtab;
1927 
1928 	if (*strtab == NULL)
1929 		return (0);
1930 
1931 	return (ef->ddbstrcnt);
1932 }
1933 
1934 #ifdef VIMAGE
1935 static void
1936 link_elf_propagate_vnets(linker_file_t lf)
1937 {
1938 	elf_file_t ef = (elf_file_t)lf;
1939 	int size;
1940 
1941 	if (ef->vnet_base != 0) {
1942 		size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
1943 		vnet_data_copy((void *)ef->vnet_base, size);
1944 	}
1945 }
1946 #endif
1947 
1948 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) || defined(__powerpc__)
1949 /*
1950  * Use this lookup routine when performing relocations early during boot.
1951  * The generic lookup routine depends on kobj, which is not initialized
1952  * at that point.
1953  */
1954 static int
1955 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused,
1956     Elf_Addr *res)
1957 {
1958 	elf_file_t ef;
1959 	const Elf_Sym *symp;
1960 	caddr_t val;
1961 
1962 	ef = (elf_file_t)lf;
1963 	symp = ef->symtab + symidx;
1964 	if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) {
1965 		val = (caddr_t)ef->address + symp->st_value;
1966 		*res = ((Elf_Addr (*)(void))val)();
1967 		return (0);
1968 	}
1969 	return (ENOENT);
1970 }
1971 
1972 void
1973 link_elf_ireloc(caddr_t kmdp)
1974 {
1975 	struct elf_file eff;
1976 	elf_file_t ef;
1977 
1978 	TSENTER();
1979 	ef = &eff;
1980 
1981 	bzero_early(ef, sizeof(*ef));
1982 
1983 	ef->modptr = kmdp;
1984 	ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
1985 
1986 #ifdef RELOCATABLE_KERNEL
1987 	ef->address = (caddr_t) (__startkernel - KERNBASE);
1988 #else
1989 	ef->address = 0;
1990 #endif
1991 	parse_dynamic(ef);
1992 
1993 	link_elf_preload_parse_symbols(ef);
1994 	relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true);
1995 	TSEXIT();
1996 }
1997 
1998 #if defined(__aarch64__) || defined(__amd64__)
1999 void
2000 link_elf_late_ireloc(void)
2001 {
2002 	elf_file_t ef;
2003 
2004 	KASSERT(linker_kernel_file != NULL,
2005 	    ("link_elf_late_ireloc: No kernel linker file found"));
2006 	ef = (elf_file_t)linker_kernel_file;
2007 
2008 	relocate_file1(ef, elf_lookup_ifunc, elf_reloc_late, true);
2009 }
2010 #endif
2011 #endif
2012