xref: /freebsd/sys/kern/link_elf.c (revision b1c5f60ce87cc2f179dfb81de507d9b7bf59564c)
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_lookup_debug_symbol(linker_file_t, const char *,
148 		    c_linker_sym_t *);
149 static int	link_elf_symbol_values(linker_file_t, c_linker_sym_t,
150 		    linker_symval_t *);
151 static int	link_elf_debug_symbol_values(linker_file_t, c_linker_sym_t,
152 		    linker_symval_t*);
153 static int	link_elf_search_symbol(linker_file_t, caddr_t,
154 		    c_linker_sym_t *, long *);
155 
156 static void	link_elf_unload_file(linker_file_t);
157 static void	link_elf_unload_preload(linker_file_t);
158 static int	link_elf_lookup_set(linker_file_t, const char *,
159 		    void ***, void ***, int *);
160 static int	link_elf_each_function_name(linker_file_t,
161 		    int (*)(const char *, void *), void *);
162 static int	link_elf_each_function_nameval(linker_file_t,
163 		    linker_function_nameval_callback_t, void *);
164 static void	link_elf_reloc_local(linker_file_t);
165 static long	link_elf_symtab_get(linker_file_t, const Elf_Sym **);
166 static long	link_elf_strtab_get(linker_file_t, caddr_t *);
167 static int	elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
168 
169 static kobj_method_t link_elf_methods[] = {
170 	KOBJMETHOD(linker_lookup_symbol,	link_elf_lookup_symbol),
171 	KOBJMETHOD(linker_lookup_debug_symbol,	link_elf_lookup_debug_symbol),
172 	KOBJMETHOD(linker_symbol_values,	link_elf_symbol_values),
173 	KOBJMETHOD(linker_debug_symbol_values,	link_elf_debug_symbol_values),
174 	KOBJMETHOD(linker_search_symbol,	link_elf_search_symbol),
175 	KOBJMETHOD(linker_unload,		link_elf_unload_file),
176 	KOBJMETHOD(linker_load_file,		link_elf_load_file),
177 	KOBJMETHOD(linker_link_preload,		link_elf_link_preload),
178 	KOBJMETHOD(linker_link_preload_finish,	link_elf_link_preload_finish),
179 	KOBJMETHOD(linker_lookup_set,		link_elf_lookup_set),
180 	KOBJMETHOD(linker_each_function_name,	link_elf_each_function_name),
181 	KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
182 	KOBJMETHOD(linker_ctf_get,		link_elf_ctf_get),
183 	KOBJMETHOD(linker_symtab_get,		link_elf_symtab_get),
184 	KOBJMETHOD(linker_strtab_get,		link_elf_strtab_get),
185 	KOBJMETHOD_END
186 };
187 
188 static struct linker_class link_elf_class = {
189 #if ELF_TARG_CLASS == ELFCLASS32
190 	"elf32",
191 #else
192 	"elf64",
193 #endif
194 	link_elf_methods, sizeof(struct elf_file)
195 };
196 
197 static bool link_elf_leak_locals = true;
198 SYSCTL_BOOL(_debug, OID_AUTO, link_elf_leak_locals,
199     CTLFLAG_RWTUN, &link_elf_leak_locals, 0,
200     "Allow local symbols to participate in global module symbol resolution");
201 
202 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase,
203     const void *data, int type, elf_lookup_fn lookup);
204 
205 static int	parse_dynamic(elf_file_t);
206 static int	relocate_file(elf_file_t);
207 static int	relocate_file1(elf_file_t ef, elf_lookup_fn lookup,
208 		    elf_reloc_fn reloc, bool ifuncs);
209 static int	link_elf_preload_parse_symbols(elf_file_t);
210 
211 static struct elf_set_head set_pcpu_list;
212 #ifdef VIMAGE
213 static struct elf_set_head set_vnet_list;
214 #endif
215 
216 static void
217 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
218 {
219 	struct elf_set *set, *iter;
220 
221 	set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
222 	set->es_start = start;
223 	set->es_stop = stop;
224 	set->es_base = base;
225 
226 	TAILQ_FOREACH(iter, list, es_link) {
227 		KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
228 		    (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
229 		    ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
230 		    (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
231 		    (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
232 
233 		if (iter->es_start > set->es_start) {
234 			TAILQ_INSERT_BEFORE(iter, set, es_link);
235 			break;
236 		}
237 	}
238 
239 	if (iter == NULL)
240 		TAILQ_INSERT_TAIL(list, set, es_link);
241 }
242 
243 static int
244 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
245 {
246 	struct elf_set *set;
247 
248 	TAILQ_FOREACH(set, list, es_link) {
249 		if (addr < set->es_start)
250 			return (0);
251 		if (addr < set->es_stop) {
252 			*start = set->es_start;
253 			*base = set->es_base;
254 			return (1);
255 		}
256 	}
257 
258 	return (0);
259 }
260 
261 static void
262 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
263 {
264 	struct elf_set *set;
265 
266 	TAILQ_FOREACH(set, list, es_link) {
267 		if (start < set->es_start)
268 			break;
269 		if (start == set->es_start) {
270 			TAILQ_REMOVE(list, set, es_link);
271 			free(set, M_LINKER);
272 			return;
273 		}
274 	}
275 	KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
276 	    (uintmax_t)start));
277 }
278 
279 #ifdef GDB
280 static void	r_debug_state(struct r_debug *, struct link_map *);
281 
282 /*
283  * A list of loaded modules for GDB to use for loading symbols.
284  */
285 struct r_debug r_debug;
286 
287 #define GDB_STATE(s) do {				\
288 	r_debug.r_state = s; r_debug_state(NULL, NULL);	\
289 } while (0)
290 
291 /*
292  * Function for the debugger to set a breakpoint on to gain control.
293  */
294 static void
295 r_debug_state(struct r_debug *dummy_one __unused,
296 	      struct link_map *dummy_two __unused)
297 {
298 }
299 
300 static void
301 link_elf_add_gdb(struct link_map *l)
302 {
303 	struct link_map *prev;
304 
305 	l->l_next = NULL;
306 
307 	if (r_debug.r_map == NULL) {
308 		/* Add first. */
309 		l->l_prev = NULL;
310 		r_debug.r_map = l;
311 	} else {
312 		/* Append to list. */
313 		for (prev = r_debug.r_map;
314 		    prev->l_next != NULL;
315 		    prev = prev->l_next)
316 			;
317 		l->l_prev = prev;
318 		prev->l_next = l;
319 	}
320 }
321 
322 static void
323 link_elf_delete_gdb(struct link_map *l)
324 {
325 	if (l->l_prev == NULL) {
326 		/* Remove first. */
327 		if ((r_debug.r_map = l->l_next) != NULL)
328 			l->l_next->l_prev = NULL;
329 	} else {
330 		/* Remove any but first. */
331 		if ((l->l_prev->l_next = l->l_next) != NULL)
332 			l->l_next->l_prev = l->l_prev;
333 	}
334 }
335 #endif /* GDB */
336 
337 /*
338  * The kernel symbol table starts here.
339  */
340 extern struct _dynamic _DYNAMIC;
341 
342 static void
343 link_elf_error(const char *filename, const char *s)
344 {
345 	if (filename == NULL)
346 		printf("kldload: %s\n", s);
347 	else
348 		printf("kldload: %s: %s\n", filename, s);
349 }
350 
351 static void
352 link_elf_invoke_ctors(caddr_t addr, size_t size)
353 {
354 	void (**ctor)(void);
355 	size_t i, cnt;
356 
357 	if (addr == NULL || size == 0)
358 		return;
359 	cnt = size / sizeof(*ctor);
360 	ctor = (void *)addr;
361 	for (i = 0; i < cnt; i++) {
362 		if (ctor[i] != NULL)
363 			(*ctor[i])();
364 	}
365 }
366 
367 /*
368  * Actions performed after linking/loading both the preloaded kernel and any
369  * modules; whether preloaded or dynamicly loaded.
370  */
371 static int
372 link_elf_link_common_finish(linker_file_t lf)
373 {
374 #ifdef GDB
375 	elf_file_t ef = (elf_file_t)lf;
376 	char *newfilename;
377 #endif
378 	int error;
379 
380 	/* Notify MD code that a module is being loaded. */
381 	error = elf_cpu_load_file(lf);
382 	if (error != 0)
383 		return (error);
384 
385 #ifdef GDB
386 	GDB_STATE(RT_ADD);
387 	ef->gdb.l_addr = lf->address;
388 	newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
389 	strcpy(newfilename, lf->filename);
390 	ef->gdb.l_name = newfilename;
391 	ef->gdb.l_ld = ef->dynamic;
392 	link_elf_add_gdb(&ef->gdb);
393 	GDB_STATE(RT_CONSISTENT);
394 #endif
395 
396 	/* Invoke .ctors */
397 	link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
398 	return (0);
399 }
400 
401 #ifdef RELOCATABLE_KERNEL
402 /*
403  * __startkernel and __endkernel are symbols set up as relocation canaries.
404  *
405  * They are defined in locore to reference linker script symbols at the
406  * beginning and end of the LOAD area. This has the desired side effect of
407  * giving us variables that have relative relocations pointing at them, so
408  * relocation of the kernel object will cause the variables to be updated
409  * automatically by the runtime linker when we initialize.
410  *
411  * There are two main reasons to relocate the kernel:
412  * 1) If the loader needed to load the kernel at an alternate load address.
413  * 2) If the kernel is switching address spaces on machines like POWER9
414  *    under Radix where the high bits of the effective address are used to
415  *    differentiate between hypervisor, host, guest, and problem state.
416  */
417 extern vm_offset_t __startkernel, __endkernel;
418 #endif
419 
420 static unsigned long kern_relbase = KERNBASE;
421 
422 SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD,
423 	SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address");
424 SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD,
425 	&kern_relbase, 0, "Kernel relocated base address");
426 
427 static void
428 link_elf_init(void* arg)
429 {
430 	Elf_Dyn *dp;
431 	Elf_Addr *ctors_addrp;
432 	Elf_Size *ctors_sizep;
433 	caddr_t modptr, baseptr, sizeptr;
434 	elf_file_t ef;
435 	const char *modname;
436 
437 	linker_add_class(&link_elf_class);
438 
439 	dp = (Elf_Dyn *)&_DYNAMIC;
440 	modname = NULL;
441 	modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
442 	if (modptr == NULL)
443 		modptr = preload_search_by_type("elf kernel");
444 	modname = (char *)preload_search_info(modptr, MODINFO_NAME);
445 	if (modname == NULL)
446 		modname = "kernel";
447 	linker_kernel_file = linker_make_file(modname, &link_elf_class);
448 	if (linker_kernel_file == NULL)
449 		panic("%s: Can't create linker structures for kernel",
450 		    __func__);
451 
452 	ef = (elf_file_t) linker_kernel_file;
453 	ef->preloaded = 1;
454 #ifdef RELOCATABLE_KERNEL
455 	/* Compute relative displacement */
456 	ef->address = (caddr_t) (__startkernel - KERNBASE);
457 #else
458 	ef->address = 0;
459 #endif
460 #ifdef SPARSE_MAPPING
461 	ef->object = NULL;
462 #endif
463 	ef->dynamic = dp;
464 
465 	if (dp != NULL)
466 		parse_dynamic(ef);
467 #ifdef RELOCATABLE_KERNEL
468 	linker_kernel_file->address = (caddr_t)__startkernel;
469 	linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
470 	kern_relbase = (unsigned long)__startkernel;
471 #else
472 	linker_kernel_file->address += KERNBASE;
473 	linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
474 #endif
475 
476 	if (modptr != NULL) {
477 		ef->modptr = modptr;
478 		baseptr = preload_search_info(modptr, MODINFO_ADDR);
479 		if (baseptr != NULL)
480 			linker_kernel_file->address = *(caddr_t *)baseptr;
481 		sizeptr = preload_search_info(modptr, MODINFO_SIZE);
482 		if (sizeptr != NULL)
483 			linker_kernel_file->size = *(size_t *)sizeptr;
484 		ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
485 			MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
486 		ctors_sizep = (Elf_Size *)preload_search_info(modptr,
487 			MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
488 		if (ctors_addrp != NULL && ctors_sizep != NULL) {
489 			linker_kernel_file->ctors_addr = ef->address +
490 			    *ctors_addrp;
491 			linker_kernel_file->ctors_size = *ctors_sizep;
492 		}
493 	}
494 	(void)link_elf_preload_parse_symbols(ef);
495 
496 #ifdef GDB
497 	r_debug.r_map = NULL;
498 	r_debug.r_brk = r_debug_state;
499 	r_debug.r_state = RT_CONSISTENT;
500 #endif
501 
502 	(void)link_elf_link_common_finish(linker_kernel_file);
503 	linker_kernel_file->flags |= LINKER_FILE_LINKED;
504 	TAILQ_INIT(&set_pcpu_list);
505 #ifdef VIMAGE
506 	TAILQ_INIT(&set_vnet_list);
507 #endif
508 }
509 
510 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL);
511 
512 static int
513 link_elf_preload_parse_symbols(elf_file_t ef)
514 {
515 	caddr_t pointer;
516 	caddr_t ssym, esym, base;
517 	caddr_t strtab;
518 	int strcnt;
519 	Elf_Sym *symtab;
520 	int symcnt;
521 
522 	if (ef->modptr == NULL)
523 		return (0);
524 	pointer = preload_search_info(ef->modptr,
525 	    MODINFO_METADATA | MODINFOMD_SSYM);
526 	if (pointer == NULL)
527 		return (0);
528 	ssym = *(caddr_t *)pointer;
529 	pointer = preload_search_info(ef->modptr,
530 	    MODINFO_METADATA | MODINFOMD_ESYM);
531 	if (pointer == NULL)
532 		return (0);
533 	esym = *(caddr_t *)pointer;
534 
535 	base = ssym;
536 
537 	symcnt = *(long *)base;
538 	base += sizeof(long);
539 	symtab = (Elf_Sym *)base;
540 	base += roundup(symcnt, sizeof(long));
541 
542 	if (base > esym || base < ssym) {
543 		printf("Symbols are corrupt!\n");
544 		return (EINVAL);
545 	}
546 
547 	strcnt = *(long *)base;
548 	base += sizeof(long);
549 	strtab = base;
550 	base += roundup(strcnt, sizeof(long));
551 
552 	if (base > esym || base < ssym) {
553 		printf("Symbols are corrupt!\n");
554 		return (EINVAL);
555 	}
556 
557 	ef->ddbsymtab = symtab;
558 	ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
559 	ef->ddbstrtab = strtab;
560 	ef->ddbstrcnt = strcnt;
561 
562 	return (0);
563 }
564 
565 static int
566 parse_dynamic(elf_file_t ef)
567 {
568 	Elf_Dyn *dp;
569 	int plttype = DT_REL;
570 
571 	for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
572 		switch (dp->d_tag) {
573 		case DT_HASH:
574 		{
575 			/* From src/libexec/rtld-elf/rtld.c */
576 			const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
577 			    (ef->address + dp->d_un.d_ptr);
578 			ef->nbuckets = hashtab[0];
579 			ef->nchains = hashtab[1];
580 			ef->buckets = hashtab + 2;
581 			ef->chains = ef->buckets + ef->nbuckets;
582 			break;
583 		}
584 		case DT_STRTAB:
585 			ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
586 			break;
587 		case DT_STRSZ:
588 			ef->strsz = dp->d_un.d_val;
589 			break;
590 		case DT_SYMTAB:
591 			ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
592 			break;
593 		case DT_SYMENT:
594 			if (dp->d_un.d_val != sizeof(Elf_Sym))
595 				return (ENOEXEC);
596 			break;
597 		case DT_PLTGOT:
598 			ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
599 			break;
600 		case DT_REL:
601 			ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
602 			break;
603 		case DT_RELSZ:
604 			ef->relsize = dp->d_un.d_val;
605 			break;
606 		case DT_RELENT:
607 			if (dp->d_un.d_val != sizeof(Elf_Rel))
608 				return (ENOEXEC);
609 			break;
610 		case DT_JMPREL:
611 			ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
612 			break;
613 		case DT_PLTRELSZ:
614 			ef->pltrelsize = dp->d_un.d_val;
615 			break;
616 		case DT_RELA:
617 			ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
618 			break;
619 		case DT_RELASZ:
620 			ef->relasize = dp->d_un.d_val;
621 			break;
622 		case DT_RELAENT:
623 			if (dp->d_un.d_val != sizeof(Elf_Rela))
624 				return (ENOEXEC);
625 			break;
626 		case DT_PLTREL:
627 			plttype = dp->d_un.d_val;
628 			if (plttype != DT_REL && plttype != DT_RELA)
629 				return (ENOEXEC);
630 			break;
631 #ifdef GDB
632 		case DT_DEBUG:
633 			dp->d_un.d_ptr = (Elf_Addr)&r_debug;
634 			break;
635 #endif
636 		}
637 	}
638 
639 	if (plttype == DT_RELA) {
640 		ef->pltrela = (const Elf_Rela *)ef->pltrel;
641 		ef->pltrel = NULL;
642 		ef->pltrelasize = ef->pltrelsize;
643 		ef->pltrelsize = 0;
644 	}
645 
646 	ef->ddbsymtab = ef->symtab;
647 	ef->ddbsymcnt = ef->nchains;
648 	ef->ddbstrtab = ef->strtab;
649 	ef->ddbstrcnt = ef->strsz;
650 
651 	return elf_cpu_parse_dynamic(ef->address, ef->dynamic);
652 }
653 
654 #define	LS_PADDING	0x90909090
655 static int
656 parse_dpcpu(elf_file_t ef)
657 {
658 	int error, size;
659 #if defined(__i386__)
660 	uint32_t pad;
661 #endif
662 
663 	ef->pcpu_start = 0;
664 	ef->pcpu_stop = 0;
665 	error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
666 	    (void ***)&ef->pcpu_stop, NULL);
667 	/* Error just means there is no pcpu set to relocate. */
668 	if (error != 0)
669 		return (0);
670 	size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start;
671 	/* Empty set? */
672 	if (size < 1)
673 		return (0);
674 #if defined(__i386__)
675 	/* In case we do find __start/stop_set_ symbols double-check. */
676 	if (size < 4) {
677 		uprintf("Kernel module '%s' must be recompiled with "
678 		    "linker script\n", ef->lf.pathname);
679 		return (ENOEXEC);
680 	}
681 
682 	/* Padding from linker-script correct? */
683 	pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad));
684 	if (pad != LS_PADDING) {
685 		uprintf("Kernel module '%s' must be recompiled with "
686 		    "linker script, invalid padding %#04x (%#04x)\n",
687 		    ef->lf.pathname, pad, LS_PADDING);
688 		return (ENOEXEC);
689 	}
690 	/* If we only have valid padding, nothing to do. */
691 	if (size == 4)
692 		return (0);
693 #endif
694 	/*
695 	 * Allocate space in the primary pcpu area.  Copy in our
696 	 * initialization from the data section and then initialize
697 	 * all per-cpu storage from that.
698 	 */
699 	ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size);
700 	if (ef->pcpu_base == 0) {
701 		printf("%s: pcpu module space is out of space; "
702 		    "cannot allocate %d for %s\n",
703 		    __func__, size, ef->lf.pathname);
704 		return (ENOSPC);
705 	}
706 	memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size);
707 	dpcpu_copy((void *)ef->pcpu_base, size);
708 	elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
709 	    ef->pcpu_base);
710 
711 	return (0);
712 }
713 
714 #ifdef VIMAGE
715 static int
716 parse_vnet(elf_file_t ef)
717 {
718 	int error, size;
719 #if defined(__i386__)
720 	uint32_t pad;
721 #endif
722 
723 	ef->vnet_start = 0;
724 	ef->vnet_stop = 0;
725 	error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
726 	    (void ***)&ef->vnet_stop, NULL);
727 	/* Error just means there is no vnet data set to relocate. */
728 	if (error != 0)
729 		return (0);
730 	size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
731 	/* Empty set? */
732 	if (size < 1)
733 		return (0);
734 #if defined(__i386__)
735 	/* In case we do find __start/stop_set_ symbols double-check. */
736 	if (size < 4) {
737 		uprintf("Kernel module '%s' must be recompiled with "
738 		    "linker script\n", ef->lf.pathname);
739 		return (ENOEXEC);
740 	}
741 
742 	/* Padding from linker-script correct? */
743 	pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad));
744 	if (pad != LS_PADDING) {
745 		uprintf("Kernel module '%s' must be recompiled with "
746 		    "linker script, invalid padding %#04x (%#04x)\n",
747 		    ef->lf.pathname, pad, LS_PADDING);
748 		return (ENOEXEC);
749 	}
750 	/* If we only have valid padding, nothing to do. */
751 	if (size == 4)
752 		return (0);
753 #endif
754 	/*
755 	 * Allocate space in the primary vnet area.  Copy in our
756 	 * initialization from the data section and then initialize
757 	 * all per-vnet storage from that.
758 	 */
759 	ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size);
760 	if (ef->vnet_base == 0) {
761 		printf("%s: vnet module space is out of space; "
762 		    "cannot allocate %d for %s\n",
763 		    __func__, size, ef->lf.pathname);
764 		return (ENOSPC);
765 	}
766 	memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size);
767 	vnet_data_copy((void *)ef->vnet_base, size);
768 	elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
769 	    ef->vnet_base);
770 
771 	return (0);
772 }
773 #endif
774 #undef LS_PADDING
775 
776 /*
777  * Apply the specified protection to the loadable segments of a preloaded linker
778  * file.
779  */
780 static int
781 preload_protect(elf_file_t ef, vm_prot_t prot)
782 {
783 #if defined(__aarch64__) || defined(__amd64__)
784 	Elf_Ehdr *hdr;
785 	Elf_Phdr *phdr, *phlimit;
786 	vm_prot_t nprot;
787 	int error;
788 
789 	error = 0;
790 	hdr = (Elf_Ehdr *)ef->address;
791 	phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff);
792 	phlimit = phdr + hdr->e_phnum;
793 	for (; phdr < phlimit; phdr++) {
794 		if (phdr->p_type != PT_LOAD)
795 			continue;
796 
797 		nprot = prot | VM_PROT_READ;
798 		if ((phdr->p_flags & PF_W) != 0)
799 			nprot |= VM_PROT_WRITE;
800 		if ((phdr->p_flags & PF_X) != 0)
801 			nprot |= VM_PROT_EXECUTE;
802 		error = pmap_change_prot((vm_offset_t)ef->address +
803 		    phdr->p_vaddr, round_page(phdr->p_memsz), nprot);
804 		if (error != 0)
805 			break;
806 	}
807 	return (error);
808 #else
809 	return (0);
810 #endif
811 }
812 
813 #ifdef __arm__
814 /*
815  * Locate the ARM exception/unwind table info for DDB and stack(9) use by
816  * searching for the section header that describes it.  There may be no unwind
817  * info, for example in a module containing only data.
818  */
819 static void
820 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr)
821 {
822 	int i;
823 
824 	for (i = 0; i < nhdr; i++) {
825 		if (shdr[i].sh_type == SHT_ARM_EXIDX) {
826 			lf->exidx_addr = shdr[i].sh_addr + lf->address;
827 			lf->exidx_size = shdr[i].sh_size;
828 			break;
829 		}
830 	}
831 }
832 
833 /*
834  * Locate the section headers metadata in a preloaded module, then use it to
835  * locate the exception/unwind table in the module.  The size of the metadata
836  * block is stored in a uint32 word immediately before the data itself, and a
837  * comment in preload_search_info() says it is safe to rely on that.
838  */
839 static void
840 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr)
841 {
842 	uint32_t *modinfo;
843 	Elf_Shdr *shdr;
844 	uint32_t  nhdr;
845 
846 	modinfo = (uint32_t *)preload_search_info(modptr,
847 	    MODINFO_METADATA | MODINFOMD_SHDR);
848 	if (modinfo != NULL) {
849 		shdr = (Elf_Shdr *)modinfo;
850 		nhdr = modinfo[-1] / sizeof(Elf_Shdr);
851 		link_elf_locate_exidx(lf, shdr, nhdr);
852 	}
853 }
854 
855 #endif /* __arm__ */
856 
857 static int
858 link_elf_link_preload(linker_class_t cls, const char *filename,
859     linker_file_t *result)
860 {
861 	Elf_Addr *ctors_addrp;
862 	Elf_Size *ctors_sizep;
863 	caddr_t modptr, baseptr, sizeptr, dynptr;
864 	char *type;
865 	elf_file_t ef;
866 	linker_file_t lf;
867 	int error;
868 	vm_offset_t dp;
869 
870 	/* Look to see if we have the file preloaded */
871 	modptr = preload_search_by_name(filename);
872 	if (modptr == NULL)
873 		return (ENOENT);
874 
875 	type = (char *)preload_search_info(modptr, MODINFO_TYPE);
876 	baseptr = preload_search_info(modptr, MODINFO_ADDR);
877 	sizeptr = preload_search_info(modptr, MODINFO_SIZE);
878 	dynptr = preload_search_info(modptr,
879 	    MODINFO_METADATA | MODINFOMD_DYNAMIC);
880 	if (type == NULL ||
881 	    (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
882 	     strcmp(type, "elf module") != 0))
883 		return (EFTYPE);
884 	if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
885 		return (EINVAL);
886 
887 	lf = linker_make_file(filename, &link_elf_class);
888 	if (lf == NULL)
889 		return (ENOMEM);
890 
891 	ef = (elf_file_t) lf;
892 	ef->preloaded = 1;
893 	ef->modptr = modptr;
894 	ef->address = *(caddr_t *)baseptr;
895 #ifdef SPARSE_MAPPING
896 	ef->object = NULL;
897 #endif
898 	dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
899 	ef->dynamic = (Elf_Dyn *)dp;
900 	lf->address = ef->address;
901 	lf->size = *(size_t *)sizeptr;
902 
903 	ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
904 	    MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
905 	ctors_sizep = (Elf_Size *)preload_search_info(modptr,
906 	    MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
907 	if (ctors_addrp != NULL && ctors_sizep != NULL) {
908 		lf->ctors_addr = ef->address + *ctors_addrp;
909 		lf->ctors_size = *ctors_sizep;
910 	}
911 
912 #ifdef __arm__
913 	link_elf_locate_exidx_preload(lf, modptr);
914 #endif
915 
916 	error = parse_dynamic(ef);
917 	if (error == 0)
918 		error = parse_dpcpu(ef);
919 #ifdef VIMAGE
920 	if (error == 0)
921 		error = parse_vnet(ef);
922 #endif
923 	if (error == 0)
924 		error = preload_protect(ef, VM_PROT_ALL);
925 	if (error != 0) {
926 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
927 		return (error);
928 	}
929 	link_elf_reloc_local(lf);
930 	*result = lf;
931 	return (0);
932 }
933 
934 static int
935 link_elf_link_preload_finish(linker_file_t lf)
936 {
937 	elf_file_t ef;
938 	int error;
939 
940 	ef = (elf_file_t) lf;
941 	error = relocate_file(ef);
942 	if (error == 0)
943 		error = preload_protect(ef, VM_PROT_NONE);
944 	if (error != 0)
945 		return (error);
946 	(void)link_elf_preload_parse_symbols(ef);
947 
948 	return (link_elf_link_common_finish(lf));
949 }
950 
951 static int
952 link_elf_load_file(linker_class_t cls, const char* filename,
953     linker_file_t* result)
954 {
955 	struct nameidata nd;
956 	struct thread* td = curthread;	/* XXX */
957 	Elf_Ehdr *hdr;
958 	caddr_t firstpage, segbase;
959 	int nbytes, i;
960 	Elf_Phdr *phdr;
961 	Elf_Phdr *phlimit;
962 	Elf_Phdr *segs[MAXSEGS];
963 	int nsegs;
964 	Elf_Phdr *phdyn;
965 	caddr_t mapbase;
966 	size_t mapsize;
967 	Elf_Addr base_vaddr;
968 	Elf_Addr base_vlimit;
969 	int error = 0;
970 	ssize_t resid;
971 	int flags;
972 	elf_file_t ef;
973 	linker_file_t lf;
974 	Elf_Shdr *shdr;
975 	int symtabindex;
976 	int symstrindex;
977 	int shstrindex;
978 	int symcnt;
979 	int strcnt;
980 	char *shstrs;
981 
982 	shdr = NULL;
983 	lf = NULL;
984 	shstrs = NULL;
985 
986 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename);
987 	flags = FREAD;
988 	error = vn_open(&nd, &flags, 0, NULL);
989 	if (error != 0)
990 		return (error);
991 	NDFREE_PNBUF(&nd);
992 	if (nd.ni_vp->v_type != VREG) {
993 		error = ENOEXEC;
994 		firstpage = NULL;
995 		goto out;
996 	}
997 #ifdef MAC
998 	error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
999 	if (error != 0) {
1000 		firstpage = NULL;
1001 		goto out;
1002 	}
1003 #endif
1004 
1005 	/*
1006 	 * Read the elf header from the file.
1007 	 */
1008 	firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
1009 	hdr = (Elf_Ehdr *)firstpage;
1010 	error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
1011 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1012 	    &resid, td);
1013 	nbytes = PAGE_SIZE - resid;
1014 	if (error != 0)
1015 		goto out;
1016 
1017 	if (!IS_ELF(*hdr)) {
1018 		error = ENOEXEC;
1019 		goto out;
1020 	}
1021 
1022 	if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
1023 	    hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
1024 		link_elf_error(filename, "Unsupported file layout");
1025 		error = ENOEXEC;
1026 		goto out;
1027 	}
1028 	if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
1029 	    hdr->e_version != EV_CURRENT) {
1030 		link_elf_error(filename, "Unsupported file version");
1031 		error = ENOEXEC;
1032 		goto out;
1033 	}
1034 	if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
1035 		error = ENOSYS;
1036 		goto out;
1037 	}
1038 	if (hdr->e_machine != ELF_TARG_MACH) {
1039 		link_elf_error(filename, "Unsupported machine");
1040 		error = ENOEXEC;
1041 		goto out;
1042 	}
1043 
1044 	/*
1045 	 * We rely on the program header being in the first page.
1046 	 * This is not strictly required by the ABI specification, but
1047 	 * it seems to always true in practice.  And, it simplifies
1048 	 * things considerably.
1049 	 */
1050 	if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
1051 	      (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
1052 	      (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
1053 		link_elf_error(filename, "Unreadable program headers");
1054 
1055 	/*
1056 	 * Scan the program header entries, and save key information.
1057 	 *
1058 	 * We rely on there being exactly two load segments, text and data,
1059 	 * in that order.
1060 	 */
1061 	phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
1062 	phlimit = phdr + hdr->e_phnum;
1063 	nsegs = 0;
1064 	phdyn = NULL;
1065 	while (phdr < phlimit) {
1066 		switch (phdr->p_type) {
1067 		case PT_LOAD:
1068 			if (nsegs == MAXSEGS) {
1069 				link_elf_error(filename, "Too many sections");
1070 				error = ENOEXEC;
1071 				goto out;
1072 			}
1073 			/*
1074 			 * XXX: We just trust they come in right order ??
1075 			 */
1076 			segs[nsegs] = phdr;
1077 			++nsegs;
1078 			break;
1079 
1080 		case PT_DYNAMIC:
1081 			phdyn = phdr;
1082 			break;
1083 
1084 		case PT_INTERP:
1085 			error = ENOSYS;
1086 			goto out;
1087 		}
1088 
1089 		++phdr;
1090 	}
1091 	if (phdyn == NULL) {
1092 		link_elf_error(filename, "Object is not dynamically-linked");
1093 		error = ENOEXEC;
1094 		goto out;
1095 	}
1096 	if (nsegs == 0) {
1097 		link_elf_error(filename, "No sections");
1098 		error = ENOEXEC;
1099 		goto out;
1100 	}
1101 
1102 	/*
1103 	 * Allocate the entire address space of the object, to stake
1104 	 * out our contiguous region, and to establish the base
1105 	 * address for relocation.
1106 	 */
1107 	base_vaddr = trunc_page(segs[0]->p_vaddr);
1108 	base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
1109 	    segs[nsegs - 1]->p_memsz);
1110 	mapsize = base_vlimit - base_vaddr;
1111 
1112 	lf = linker_make_file(filename, &link_elf_class);
1113 	if (lf == NULL) {
1114 		error = ENOMEM;
1115 		goto out;
1116 	}
1117 
1118 	ef = (elf_file_t) lf;
1119 #ifdef SPARSE_MAPPING
1120 	ef->object = vm_pager_allocate(OBJT_PHYS, NULL, mapsize, VM_PROT_ALL,
1121 	    0, thread0.td_ucred);
1122 	if (ef->object == NULL) {
1123 		error = ENOMEM;
1124 		goto out;
1125 	}
1126 #ifdef __amd64__
1127 	mapbase = (caddr_t)KERNBASE;
1128 #else
1129 	mapbase = (caddr_t)vm_map_min(kernel_map);
1130 #endif
1131 	/*
1132 	 * Mapping protections are downgraded after relocation processing.
1133 	 */
1134 	error = vm_map_find(kernel_map, ef->object, 0,
1135 	    (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE,
1136 	    VM_PROT_ALL, VM_PROT_ALL, 0);
1137 	if (error != 0) {
1138 		vm_object_deallocate(ef->object);
1139 		ef->object = NULL;
1140 		goto out;
1141 	}
1142 #else
1143 	mapbase = malloc_exec(mapsize, M_LINKER, M_WAITOK);
1144 #endif
1145 	ef->address = mapbase;
1146 
1147 	/*
1148 	 * Read the text and data sections and zero the bss.
1149 	 */
1150 	for (i = 0; i < nsegs; i++) {
1151 		segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1152 
1153 #ifdef SPARSE_MAPPING
1154 		/*
1155 		 * Consecutive segments may have different mapping permissions,
1156 		 * so be strict and verify that their mappings do not overlap.
1157 		 */
1158 		if (((vm_offset_t)segbase & PAGE_MASK) != 0) {
1159 			error = EINVAL;
1160 			goto out;
1161 		}
1162 
1163 		error = vm_map_wire(kernel_map,
1164 		    (vm_offset_t)segbase,
1165 		    (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1166 		    VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
1167 		if (error != KERN_SUCCESS) {
1168 			error = ENOMEM;
1169 			goto out;
1170 		}
1171 #endif
1172 
1173 		error = vn_rdwr(UIO_READ, nd.ni_vp,
1174 		    segbase, segs[i]->p_filesz, segs[i]->p_offset,
1175 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1176 		    &resid, td);
1177 		if (error != 0)
1178 			goto out;
1179 		bzero(segbase + segs[i]->p_filesz,
1180 		    segs[i]->p_memsz - segs[i]->p_filesz);
1181 	}
1182 
1183 #ifdef GPROF
1184 	/* Update profiling information with the new text segment. */
1185 	mtx_lock(&Giant);
1186 	kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
1187 	    segs[0]->p_memsz));
1188 	mtx_unlock(&Giant);
1189 #endif
1190 
1191 	ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
1192 
1193 	lf->address = ef->address;
1194 	lf->size = mapsize;
1195 
1196 	error = parse_dynamic(ef);
1197 	if (error != 0)
1198 		goto out;
1199 	error = parse_dpcpu(ef);
1200 	if (error != 0)
1201 		goto out;
1202 #ifdef VIMAGE
1203 	error = parse_vnet(ef);
1204 	if (error != 0)
1205 		goto out;
1206 #endif
1207 	link_elf_reloc_local(lf);
1208 
1209 	VOP_UNLOCK(nd.ni_vp);
1210 	error = linker_load_dependencies(lf);
1211 	vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1212 	if (error != 0)
1213 		goto out;
1214 	error = relocate_file(ef);
1215 	if (error != 0)
1216 		goto out;
1217 
1218 #ifdef SPARSE_MAPPING
1219 	/*
1220 	 * Downgrade permissions on text segment mappings now that relocation
1221 	 * processing is complete.  Restrict permissions on read-only segments.
1222 	 */
1223 	for (i = 0; i < nsegs; i++) {
1224 		vm_prot_t prot;
1225 
1226 		if (segs[i]->p_type != PT_LOAD)
1227 			continue;
1228 
1229 		prot = VM_PROT_READ;
1230 		if ((segs[i]->p_flags & PF_W) != 0)
1231 			prot |= VM_PROT_WRITE;
1232 		if ((segs[i]->p_flags & PF_X) != 0)
1233 			prot |= VM_PROT_EXECUTE;
1234 		segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1235 		error = vm_map_protect(kernel_map,
1236 		    (vm_offset_t)segbase,
1237 		    (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1238 		    prot, 0, VM_MAP_PROTECT_SET_PROT);
1239 		if (error != KERN_SUCCESS) {
1240 			error = ENOMEM;
1241 			goto out;
1242 		}
1243 	}
1244 #endif
1245 
1246 	/*
1247 	 * Try and load the symbol table if it's present.  (you can
1248 	 * strip it!)
1249 	 */
1250 	nbytes = hdr->e_shnum * hdr->e_shentsize;
1251 	if (nbytes == 0 || hdr->e_shoff == 0)
1252 		goto nosyms;
1253 	shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1254 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1255 	    (caddr_t)shdr, nbytes, hdr->e_shoff,
1256 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1257 	    &resid, td);
1258 	if (error != 0)
1259 		goto out;
1260 
1261 	/* Read section string table */
1262 	shstrindex = hdr->e_shstrndx;
1263 	if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1264 	    shdr[shstrindex].sh_size != 0) {
1265 		nbytes = shdr[shstrindex].sh_size;
1266 		shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1267 		error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1268 		    shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1269 		    td->td_ucred, NOCRED, &resid, td);
1270 		if (error)
1271 			goto out;
1272 	}
1273 
1274 	symtabindex = -1;
1275 	symstrindex = -1;
1276 	for (i = 0; i < hdr->e_shnum; i++) {
1277 		if (shdr[i].sh_type == SHT_SYMTAB) {
1278 			symtabindex = i;
1279 			symstrindex = shdr[i].sh_link;
1280 		} else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1281 		    strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1282 			/* Record relocated address and size of .ctors. */
1283 			lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1284 			lf->ctors_size = shdr[i].sh_size;
1285 		}
1286 	}
1287 	if (symtabindex < 0 || symstrindex < 0)
1288 		goto nosyms;
1289 
1290 	symcnt = shdr[symtabindex].sh_size;
1291 	ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1292 	strcnt = shdr[symstrindex].sh_size;
1293 	ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1294 
1295 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1296 	    ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1297 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1298 	    &resid, td);
1299 	if (error != 0)
1300 		goto out;
1301 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1302 	    ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1303 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1304 	    &resid, td);
1305 	if (error != 0)
1306 		goto out;
1307 
1308 	ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1309 	ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1310 	ef->ddbstrcnt = strcnt;
1311 	ef->ddbstrtab = ef->strbase;
1312 
1313 nosyms:
1314 
1315 #ifdef __arm__
1316 	link_elf_locate_exidx(lf, shdr, hdr->e_shnum);
1317 #endif
1318 
1319 	error = link_elf_link_common_finish(lf);
1320 	if (error != 0)
1321 		goto out;
1322 
1323 	*result = lf;
1324 
1325 out:
1326 	VOP_UNLOCK(nd.ni_vp);
1327 	vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1328 	if (error != 0 && lf != NULL)
1329 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1330 	free(shdr, M_LINKER);
1331 	free(firstpage, M_LINKER);
1332 	free(shstrs, M_LINKER);
1333 
1334 	return (error);
1335 }
1336 
1337 Elf_Addr
1338 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1339 {
1340 	elf_file_t ef;
1341 
1342 	KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class,
1343 	    ("elf_relocaddr: unexpected linker file %p", lf));
1344 
1345 	ef = (elf_file_t)lf;
1346 	if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1347 		return ((x - ef->pcpu_start) + ef->pcpu_base);
1348 #ifdef VIMAGE
1349 	if (x >= ef->vnet_start && x < ef->vnet_stop)
1350 		return ((x - ef->vnet_start) + ef->vnet_base);
1351 #endif
1352 	return (x);
1353 }
1354 
1355 static void
1356 link_elf_unload_file(linker_file_t file)
1357 {
1358 	elf_file_t ef = (elf_file_t) file;
1359 
1360 	if (ef->pcpu_base != 0) {
1361 		dpcpu_free((void *)ef->pcpu_base,
1362 		    ef->pcpu_stop - ef->pcpu_start);
1363 		elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1364 	}
1365 #ifdef VIMAGE
1366 	if (ef->vnet_base != 0) {
1367 		vnet_data_free((void *)ef->vnet_base,
1368 		    ef->vnet_stop - ef->vnet_start);
1369 		elf_set_delete(&set_vnet_list, ef->vnet_start);
1370 	}
1371 #endif
1372 #ifdef GDB
1373 	if (ef->gdb.l_ld != NULL) {
1374 		GDB_STATE(RT_DELETE);
1375 		free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1376 		link_elf_delete_gdb(&ef->gdb);
1377 		GDB_STATE(RT_CONSISTENT);
1378 	}
1379 #endif
1380 
1381 	/* Notify MD code that a module is being unloaded. */
1382 	elf_cpu_unload_file(file);
1383 
1384 	if (ef->preloaded) {
1385 		link_elf_unload_preload(file);
1386 		return;
1387 	}
1388 
1389 #ifdef SPARSE_MAPPING
1390 	if (ef->object != NULL) {
1391 		vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1392 		    (vm_offset_t) ef->address
1393 		    + (ef->object->size << PAGE_SHIFT));
1394 	}
1395 #else
1396 	free(ef->address, M_LINKER);
1397 #endif
1398 	free(ef->symbase, M_LINKER);
1399 	free(ef->strbase, M_LINKER);
1400 	free(ef->ctftab, M_LINKER);
1401 	free(ef->ctfoff, M_LINKER);
1402 	free(ef->typoff, M_LINKER);
1403 }
1404 
1405 static void
1406 link_elf_unload_preload(linker_file_t file)
1407 {
1408 
1409 	if (file->pathname != NULL)
1410 		preload_delete_name(file->pathname);
1411 }
1412 
1413 static const char *
1414 symbol_name(elf_file_t ef, Elf_Size r_info)
1415 {
1416 	const Elf_Sym *ref;
1417 
1418 	if (ELF_R_SYM(r_info)) {
1419 		ref = ef->symtab + ELF_R_SYM(r_info);
1420 		return (ef->strtab + ref->st_name);
1421 	}
1422 	return (NULL);
1423 }
1424 
1425 static int
1426 symbol_type(elf_file_t ef, Elf_Size r_info)
1427 {
1428 	const Elf_Sym *ref;
1429 
1430 	if (ELF_R_SYM(r_info)) {
1431 		ref = ef->symtab + ELF_R_SYM(r_info);
1432 		return (ELF_ST_TYPE(ref->st_info));
1433 	}
1434 	return (STT_NOTYPE);
1435 }
1436 
1437 static int
1438 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc,
1439     bool ifuncs)
1440 {
1441 	const Elf_Rel *rel;
1442 	const Elf_Rela *rela;
1443 	const char *symname;
1444 
1445 #define	APPLY_RELOCS(iter, tbl, tblsize, type) do {			\
1446 	for ((iter) = (tbl); (iter) != NULL &&				\
1447 	    (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) {	\
1448 		if ((symbol_type(ef, (iter)->r_info) ==			\
1449 		    STT_GNU_IFUNC ||					\
1450 		    elf_is_ifunc_reloc((iter)->r_info)) != ifuncs)	\
1451 			continue;					\
1452 		if (reloc(&ef->lf, (Elf_Addr)ef->address,		\
1453 		    (iter), (type), lookup)) {				\
1454 			symname = symbol_name(ef, (iter)->r_info);	\
1455 			printf("link_elf: symbol %s undefined\n",	\
1456 			    symname);					\
1457 			return (ENOENT);				\
1458 		}							\
1459 	}								\
1460 } while (0)
1461 
1462 	APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL);
1463 	APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA);
1464 	APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL);
1465 	APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA);
1466 
1467 #undef APPLY_RELOCS
1468 
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  * Hash function for symbol table lookup.  Don't even think about changing
1485  * this.  It is specified by the System V ABI.
1486  */
1487 static unsigned long
1488 elf_hash(const char *name)
1489 {
1490 	const unsigned char *p = (const unsigned char *) name;
1491 	unsigned long h = 0;
1492 	unsigned long g;
1493 
1494 	while (*p != '\0') {
1495 		h = (h << 4) + *p++;
1496 		if ((g = h & 0xf0000000) != 0)
1497 			h ^= g >> 24;
1498 		h &= ~g;
1499 	}
1500 	return (h);
1501 }
1502 
1503 static int
1504 link_elf_lookup_symbol1(linker_file_t lf, const char *name, c_linker_sym_t *sym,
1505     bool see_local)
1506 {
1507 	elf_file_t ef = (elf_file_t) lf;
1508 	unsigned long symnum;
1509 	const Elf_Sym* symp;
1510 	const char *strp;
1511 	unsigned long hash;
1512 
1513 	/* If we don't have a hash, bail. */
1514 	if (ef->buckets == NULL || ef->nbuckets == 0) {
1515 		printf("link_elf_lookup_symbol: missing symbol hash table\n");
1516 		return (ENOENT);
1517 	}
1518 
1519 	/* First, search hashed global symbols */
1520 	hash = elf_hash(name);
1521 	symnum = ef->buckets[hash % ef->nbuckets];
1522 
1523 	while (symnum != STN_UNDEF) {
1524 		if (symnum >= ef->nchains) {
1525 			printf("%s: corrupt symbol table\n", __func__);
1526 			return (ENOENT);
1527 		}
1528 
1529 		symp = ef->symtab + symnum;
1530 		if (symp->st_name == 0) {
1531 			printf("%s: corrupt symbol table\n", __func__);
1532 			return (ENOENT);
1533 		}
1534 
1535 		strp = ef->strtab + symp->st_name;
1536 
1537 		if (strcmp(name, strp) == 0) {
1538 			if (symp->st_shndx != SHN_UNDEF ||
1539 			    (symp->st_value != 0 &&
1540 			    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1541 			    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1542 				if (see_local ||
1543 				    ELF_ST_BIND(symp->st_info) != STB_LOCAL) {
1544 					*sym = (c_linker_sym_t) symp;
1545 					return (0);
1546 				}
1547 			}
1548 			return (ENOENT);
1549 		}
1550 
1551 		symnum = ef->chains[symnum];
1552 	}
1553 
1554 	return (ENOENT);
1555 }
1556 
1557 static int
1558 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1559 {
1560 	if (link_elf_leak_locals)
1561 		return (link_elf_lookup_debug_symbol(lf, name, sym));
1562 	return (link_elf_lookup_symbol1(lf, name, sym, false));
1563 }
1564 
1565 static int
1566 link_elf_lookup_debug_symbol(linker_file_t lf, const char *name,
1567     c_linker_sym_t *sym)
1568 {
1569 	elf_file_t ef = (elf_file_t)lf;
1570 	const Elf_Sym* symp;
1571 	const char *strp;
1572 	int i;
1573 
1574 	if (link_elf_lookup_symbol1(lf, name, sym, true) == 0)
1575 		return (0);
1576 
1577 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1578 		strp = ef->ddbstrtab + symp->st_name;
1579 		if (strcmp(name, strp) == 0) {
1580 			if (symp->st_shndx != SHN_UNDEF ||
1581 			    (symp->st_value != 0 &&
1582 			    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1583 			    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1584 				*sym = (c_linker_sym_t) symp;
1585 				return (0);
1586 			}
1587 			return (ENOENT);
1588 		}
1589 	}
1590 
1591 	return (ENOENT);
1592 }
1593 
1594 static int
1595 link_elf_symbol_values1(linker_file_t lf, c_linker_sym_t sym,
1596     linker_symval_t *symval, bool see_local)
1597 {
1598 	elf_file_t ef;
1599 	const Elf_Sym *es;
1600 	caddr_t val;
1601 
1602 	ef = (elf_file_t)lf;
1603 	es = (const Elf_Sym *)sym;
1604 	if (es >= ef->symtab && es < ef->symtab + ef->nchains) {
1605 		if (!see_local && ELF_ST_BIND(es->st_info) == STB_LOCAL)
1606 			return (ENOENT);
1607 		symval->name = ef->strtab + es->st_name;
1608 		val = (caddr_t)ef->address + es->st_value;
1609 		if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1610 			val = ((caddr_t (*)(void))val)();
1611 		symval->value = val;
1612 		symval->size = es->st_size;
1613 		return (0);
1614 	}
1615 	return (ENOENT);
1616 }
1617 
1618 static int
1619 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1620     linker_symval_t *symval)
1621 {
1622 	if (link_elf_leak_locals)
1623 		return (link_elf_debug_symbol_values(lf, sym, symval));
1624 	return (link_elf_symbol_values1(lf, sym, symval, false));
1625 }
1626 
1627 static int
1628 link_elf_debug_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1629     linker_symval_t *symval)
1630 {
1631 	elf_file_t ef = (elf_file_t)lf;
1632 	const Elf_Sym *es = (const Elf_Sym *)sym;
1633 	caddr_t val;
1634 
1635 	if (link_elf_symbol_values1(lf, sym, symval, true) == 0)
1636 		return (0);
1637 	if (ef->symtab == ef->ddbsymtab)
1638 		return (ENOENT);
1639 
1640 	if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1641 		symval->name = ef->ddbstrtab + es->st_name;
1642 		val = (caddr_t)ef->address + es->st_value;
1643 		if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1644 			val = ((caddr_t (*)(void))val)();
1645 		symval->value = val;
1646 		symval->size = es->st_size;
1647 		return (0);
1648 	}
1649 	return (ENOENT);
1650 }
1651 
1652 static int
1653 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1654     c_linker_sym_t *sym, long *diffp)
1655 {
1656 	elf_file_t ef = (elf_file_t)lf;
1657 	u_long off = (uintptr_t)(void *)value;
1658 	u_long diff = off;
1659 	u_long st_value;
1660 	const Elf_Sym *es;
1661 	const Elf_Sym *best = NULL;
1662 	int i;
1663 
1664 	for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1665 		if (es->st_name == 0)
1666 			continue;
1667 		st_value = es->st_value + (uintptr_t) (void *) ef->address;
1668 		if (off >= st_value) {
1669 			if (off - st_value < diff) {
1670 				diff = off - st_value;
1671 				best = es;
1672 				if (diff == 0)
1673 					break;
1674 			} else if (off - st_value == diff) {
1675 				best = es;
1676 			}
1677 		}
1678 	}
1679 	if (best == NULL)
1680 		*diffp = off;
1681 	else
1682 		*diffp = diff;
1683 	*sym = (c_linker_sym_t) best;
1684 
1685 	return (0);
1686 }
1687 
1688 /*
1689  * Look up a linker set on an ELF system.
1690  */
1691 static int
1692 link_elf_lookup_set(linker_file_t lf, const char *name,
1693     void ***startp, void ***stopp, int *countp)
1694 {
1695 	c_linker_sym_t sym;
1696 	linker_symval_t symval;
1697 	char *setsym;
1698 	void **start, **stop;
1699 	int len, error = 0, count;
1700 
1701 	len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1702 	setsym = malloc(len, M_LINKER, M_WAITOK);
1703 
1704 	/* get address of first entry */
1705 	snprintf(setsym, len, "%s%s", "__start_set_", name);
1706 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1707 	if (error != 0)
1708 		goto out;
1709 	link_elf_symbol_values(lf, sym, &symval);
1710 	if (symval.value == 0) {
1711 		error = ESRCH;
1712 		goto out;
1713 	}
1714 	start = (void **)symval.value;
1715 
1716 	/* get address of last entry */
1717 	snprintf(setsym, len, "%s%s", "__stop_set_", name);
1718 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1719 	if (error != 0)
1720 		goto out;
1721 	link_elf_symbol_values(lf, sym, &symval);
1722 	if (symval.value == 0) {
1723 		error = ESRCH;
1724 		goto out;
1725 	}
1726 	stop = (void **)symval.value;
1727 
1728 	/* and the number of entries */
1729 	count = stop - start;
1730 
1731 	/* and copy out */
1732 	if (startp != NULL)
1733 		*startp = start;
1734 	if (stopp != NULL)
1735 		*stopp = stop;
1736 	if (countp != NULL)
1737 		*countp = count;
1738 
1739 out:
1740 	free(setsym, M_LINKER);
1741 	return (error);
1742 }
1743 
1744 static int
1745 link_elf_each_function_name(linker_file_t file,
1746   int (*callback)(const char *, void *), void *opaque)
1747 {
1748 	elf_file_t ef = (elf_file_t)file;
1749 	const Elf_Sym *symp;
1750 	int i, error;
1751 
1752 	/* Exhaustive search */
1753 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1754 		if (symp->st_value != 0 &&
1755 		    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1756 		    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1757 			error = callback(ef->ddbstrtab + symp->st_name, opaque);
1758 			if (error != 0)
1759 				return (error);
1760 		}
1761 	}
1762 	return (0);
1763 }
1764 
1765 static int
1766 link_elf_each_function_nameval(linker_file_t file,
1767     linker_function_nameval_callback_t callback, void *opaque)
1768 {
1769 	linker_symval_t symval;
1770 	elf_file_t ef = (elf_file_t)file;
1771 	const Elf_Sym *symp;
1772 	int i, error;
1773 
1774 	/* Exhaustive search */
1775 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1776 		if (symp->st_value != 0 &&
1777 		    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1778 		    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1779 			error = link_elf_debug_symbol_values(file,
1780 			    (c_linker_sym_t) symp, &symval);
1781 			if (error == 0)
1782 				error = callback(file, i, &symval, opaque);
1783 			if (error != 0)
1784 				return (error);
1785 		}
1786 	}
1787 	return (0);
1788 }
1789 
1790 const Elf_Sym *
1791 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1792 {
1793 	elf_file_t ef = (elf_file_t)lf;
1794 
1795 	if (symidx >= ef->nchains)
1796 		return (NULL);
1797 	return (ef->symtab + symidx);
1798 }
1799 
1800 const char *
1801 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1802 {
1803 	elf_file_t ef = (elf_file_t)lf;
1804 	const Elf_Sym *sym;
1805 
1806 	if (symidx >= ef->nchains)
1807 		return (NULL);
1808 	sym = ef->symtab + symidx;
1809 	return (ef->strtab + sym->st_name);
1810 }
1811 
1812 /*
1813  * Symbol lookup function that can be used when the symbol index is known (ie
1814  * in relocations). It uses the symbol index instead of doing a fully fledged
1815  * hash table based lookup when such is valid. For example for local symbols.
1816  * This is not only more efficient, it's also more correct. It's not always
1817  * the case that the symbol can be found through the hash table.
1818  */
1819 static int
1820 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1821 {
1822 	elf_file_t ef = (elf_file_t)lf;
1823 	const Elf_Sym *sym;
1824 	const char *symbol;
1825 	Elf_Addr addr, start, base;
1826 
1827 	/* Don't even try to lookup the symbol if the index is bogus. */
1828 	if (symidx >= ef->nchains) {
1829 		*res = 0;
1830 		return (EINVAL);
1831 	}
1832 
1833 	sym = ef->symtab + symidx;
1834 
1835 	/*
1836 	 * Don't do a full lookup when the symbol is local. It may even
1837 	 * fail because it may not be found through the hash table.
1838 	 */
1839 	if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1840 		/* Force lookup failure when we have an insanity. */
1841 		if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1842 			*res = 0;
1843 			return (EINVAL);
1844 		}
1845 		*res = ((Elf_Addr)ef->address + sym->st_value);
1846 		return (0);
1847 	}
1848 
1849 	/*
1850 	 * XXX we can avoid doing a hash table based lookup for global
1851 	 * symbols as well. This however is not always valid, so we'll
1852 	 * just do it the hard way for now. Performance tweaks can
1853 	 * always be added.
1854 	 */
1855 
1856 	symbol = ef->strtab + sym->st_name;
1857 
1858 	/* Force a lookup failure if the symbol name is bogus. */
1859 	if (*symbol == 0) {
1860 		*res = 0;
1861 		return (EINVAL);
1862 	}
1863 
1864 	addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1865 	if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1866 		*res = 0;
1867 		return (EINVAL);
1868 	}
1869 
1870 	if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1871 		addr = addr - start + base;
1872 #ifdef VIMAGE
1873 	else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1874 		addr = addr - start + base;
1875 #endif
1876 	*res = addr;
1877 	return (0);
1878 }
1879 
1880 static void
1881 link_elf_reloc_local(linker_file_t lf)
1882 {
1883 	const Elf_Rel *rellim;
1884 	const Elf_Rel *rel;
1885 	const Elf_Rela *relalim;
1886 	const Elf_Rela *rela;
1887 	elf_file_t ef = (elf_file_t)lf;
1888 
1889 	/* Perform relocations without addend if there are any: */
1890 	if ((rel = ef->rel) != NULL) {
1891 		rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1892 		while (rel < rellim) {
1893 			elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1894 			    ELF_RELOC_REL, elf_lookup);
1895 			rel++;
1896 		}
1897 	}
1898 
1899 	/* Perform relocations with addend if there are any: */
1900 	if ((rela = ef->rela) != NULL) {
1901 		relalim = (const Elf_Rela *)
1902 		    ((const char *)ef->rela + ef->relasize);
1903 		while (rela < relalim) {
1904 			elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1905 			    ELF_RELOC_RELA, elf_lookup);
1906 			rela++;
1907 		}
1908 	}
1909 }
1910 
1911 static long
1912 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1913 {
1914 	elf_file_t ef = (elf_file_t)lf;
1915 
1916 	*symtab = ef->ddbsymtab;
1917 
1918 	if (*symtab == NULL)
1919 		return (0);
1920 
1921 	return (ef->ddbsymcnt);
1922 }
1923 
1924 static long
1925 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1926 {
1927 	elf_file_t ef = (elf_file_t)lf;
1928 
1929 	*strtab = ef->ddbstrtab;
1930 
1931 	if (*strtab == NULL)
1932 		return (0);
1933 
1934 	return (ef->ddbstrcnt);
1935 }
1936 
1937 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) || defined(__powerpc__)
1938 /*
1939  * Use this lookup routine when performing relocations early during boot.
1940  * The generic lookup routine depends on kobj, which is not initialized
1941  * at that point.
1942  */
1943 static int
1944 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused,
1945     Elf_Addr *res)
1946 {
1947 	elf_file_t ef;
1948 	const Elf_Sym *symp;
1949 	caddr_t val;
1950 
1951 	ef = (elf_file_t)lf;
1952 	symp = ef->symtab + symidx;
1953 	if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) {
1954 		val = (caddr_t)ef->address + symp->st_value;
1955 		*res = ((Elf_Addr (*)(void))val)();
1956 		return (0);
1957 	}
1958 	return (ENOENT);
1959 }
1960 
1961 void
1962 link_elf_ireloc(caddr_t kmdp)
1963 {
1964 	struct elf_file eff;
1965 	elf_file_t ef;
1966 
1967 	ef = &eff;
1968 
1969 	bzero_early(ef, sizeof(*ef));
1970 
1971 	ef->modptr = kmdp;
1972 	ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
1973 
1974 #ifdef RELOCATABLE_KERNEL
1975 	ef->address = (caddr_t) (__startkernel - KERNBASE);
1976 #else
1977 	ef->address = 0;
1978 #endif
1979 	parse_dynamic(ef);
1980 
1981 	link_elf_preload_parse_symbols(ef);
1982 	relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true);
1983 }
1984 
1985 #if defined(__aarch64__) || defined(__amd64__)
1986 void
1987 link_elf_late_ireloc(void)
1988 {
1989 	elf_file_t ef;
1990 
1991 	KASSERT(linker_kernel_file != NULL,
1992 	    ("link_elf_late_ireloc: No kernel linker file found"));
1993 	ef = (elf_file_t)linker_kernel_file;
1994 
1995 	relocate_file1(ef, elf_lookup_ifunc, elf_reloc_late, true);
1996 }
1997 #endif
1998 #endif
1999