2 * SPDX-License-Identifier: BSD-2-Clause
4 * Copyright (c) 1998-2000 Doug Rabson
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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.
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
29 #include <sys/cdefs.h>
33 #include <sys/param.h>
34 #include <sys/systm.h>
38 #include <sys/kernel.h>
40 #include <sys/malloc.h>
44 #include <sys/mutex.h>
45 #include <sys/mount.h>
48 #include <sys/namei.h>
49 #include <sys/fcntl.h>
50 #include <sys/vnode.h>
51 #include <sys/linker.h>
52 #include <sys/sysctl.h>
54 #include <machine/elf.h>
58 #include <security/mac/mac_framework.h>
61 #include <vm/vm_param.h>
63 #include <vm/vm_object.h>
64 #include <vm/vm_kern.h>
65 #include <vm/vm_extern.h>
68 #include <vm/vm_map.h>
70 #include <sys/link_elf.h>
72 #include "linker_if.h"
76 typedef struct elf_file {
77 struct linker_file lf; /* Common fields */
78 int preloaded; /* Was file pre-loaded */
79 caddr_t address; /* Relocation address */
81 vm_object_t object; /* VM object to hold file pages */
83 Elf_Dyn *dynamic; /* Symbol table etc. */
84 Elf_Hashelt nbuckets; /* DT_HASH info */
86 const Elf_Hashelt *buckets;
87 const Elf_Hashelt *chains;
89 caddr_t strtab; /* DT_STRTAB */
90 int strsz; /* DT_STRSZ */
91 const Elf_Sym *symtab; /* DT_SYMTAB */
92 Elf_Addr *got; /* DT_PLTGOT */
93 const Elf_Rel *pltrel; /* DT_JMPREL */
94 int pltrelsize; /* DT_PLTRELSZ */
95 const Elf_Rela *pltrela; /* DT_JMPREL */
96 int pltrelasize; /* DT_PLTRELSZ */
97 const Elf_Rel *rel; /* DT_REL */
98 int relsize; /* DT_RELSZ */
99 const Elf_Rela *rela; /* DT_RELA */
100 int relasize; /* DT_RELASZ */
102 const Elf_Sym *ddbsymtab; /* The symbol table we are using */
103 long ddbsymcnt; /* Number of symbols */
104 caddr_t ddbstrtab; /* String table */
105 long ddbstrcnt; /* number of bytes in string table */
106 caddr_t symbase; /* malloc'ed symbold base */
107 caddr_t strbase; /* malloc'ed string base */
108 caddr_t ctftab; /* CTF table */
109 long ctfcnt; /* number of bytes in CTF table */
110 caddr_t ctfoff; /* CTF offset table */
111 caddr_t typoff; /* Type offset table */
112 long typlen; /* Number of type entries. */
113 Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */
114 Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */
115 Elf_Addr pcpu_base; /* Relocated pcpu set address. */
117 Elf_Addr vnet_start; /* Pre-relocation vnet set start. */
118 Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */
119 Elf_Addr vnet_base; /* Relocated vnet set address. */
122 struct link_map gdb; /* hooks for gdb */
130 TAILQ_ENTRY(elf_set) es_link;
133 TAILQ_HEAD(elf_set_head, elf_set);
135 #include <kern/kern_ctf.c>
137 static int link_elf_link_common_finish(linker_file_t);
138 static int link_elf_link_preload(linker_class_t cls,
139 const char *, linker_file_t *);
140 static int link_elf_link_preload_finish(linker_file_t);
141 static int link_elf_load_file(linker_class_t, const char *,
143 static int link_elf_lookup_symbol(linker_file_t, const char *,
145 static int link_elf_lookup_debug_symbol(linker_file_t, const char *,
147 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
149 static int link_elf_debug_symbol_values(linker_file_t, c_linker_sym_t,
151 static int link_elf_search_symbol(linker_file_t, caddr_t,
152 c_linker_sym_t *, long *);
154 static void link_elf_unload_file(linker_file_t);
155 static void link_elf_unload_preload(linker_file_t);
156 static int link_elf_lookup_set(linker_file_t, const char *,
157 void ***, void ***, int *);
158 static int link_elf_each_function_name(linker_file_t,
159 int (*)(const char *, void *), void *);
160 static int link_elf_each_function_nameval(linker_file_t,
161 linker_function_nameval_callback_t, void *);
162 static void link_elf_reloc_local(linker_file_t);
163 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
164 static long link_elf_strtab_get(linker_file_t, caddr_t *);
165 static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
167 static kobj_method_t link_elf_methods[] = {
168 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
169 KOBJMETHOD(linker_lookup_debug_symbol, link_elf_lookup_debug_symbol),
170 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
171 KOBJMETHOD(linker_debug_symbol_values, link_elf_debug_symbol_values),
172 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
173 KOBJMETHOD(linker_unload, link_elf_unload_file),
174 KOBJMETHOD(linker_load_file, link_elf_load_file),
175 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
176 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
177 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
178 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
179 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
180 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
181 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
182 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
186 static struct linker_class link_elf_class = {
187 #if ELF_TARG_CLASS == ELFCLASS32
192 link_elf_methods, sizeof(struct elf_file)
195 static bool link_elf_leak_locals = true;
196 SYSCTL_BOOL(_debug, OID_AUTO, link_elf_leak_locals,
197 CTLFLAG_RWTUN, &link_elf_leak_locals, 0,
198 "Allow local symbols to participate in global module symbol resolution");
200 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase,
201 const void *data, int type, elf_lookup_fn lookup);
203 static int parse_dynamic(elf_file_t);
204 static int relocate_file(elf_file_t);
205 static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup,
206 elf_reloc_fn reloc, bool ifuncs);
207 static int link_elf_preload_parse_symbols(elf_file_t);
209 static struct elf_set_head set_pcpu_list;
211 static struct elf_set_head set_vnet_list;
215 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
217 struct elf_set *set, *iter;
219 set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
220 set->es_start = start;
224 TAILQ_FOREACH(iter, list, es_link) {
225 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
226 (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
227 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
228 (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
229 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
231 if (iter->es_start > set->es_start) {
232 TAILQ_INSERT_BEFORE(iter, set, es_link);
238 TAILQ_INSERT_TAIL(list, set, es_link);
242 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
246 TAILQ_FOREACH(set, list, es_link) {
247 if (addr < set->es_start)
249 if (addr < set->es_stop) {
250 *start = set->es_start;
251 *base = set->es_base;
260 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
264 TAILQ_FOREACH(set, list, es_link) {
265 if (start < set->es_start)
267 if (start == set->es_start) {
268 TAILQ_REMOVE(list, set, es_link);
273 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
278 static void r_debug_state(struct r_debug *, struct link_map *);
281 * A list of loaded modules for GDB to use for loading symbols.
283 struct r_debug r_debug;
285 #define GDB_STATE(s) do { \
286 r_debug.r_state = s; r_debug_state(NULL, NULL); \
290 * Function for the debugger to set a breakpoint on to gain control.
293 r_debug_state(struct r_debug *dummy_one __unused,
294 struct link_map *dummy_two __unused)
299 link_elf_add_gdb(struct link_map *l)
301 struct link_map *prev;
305 if (r_debug.r_map == NULL) {
310 /* Append to list. */
311 for (prev = r_debug.r_map;
312 prev->l_next != NULL;
321 link_elf_delete_gdb(struct link_map *l)
323 if (l->l_prev == NULL) {
325 if ((r_debug.r_map = l->l_next) != NULL)
326 l->l_next->l_prev = NULL;
328 /* Remove any but first. */
329 if ((l->l_prev->l_next = l->l_next) != NULL)
330 l->l_next->l_prev = l->l_prev;
336 * The kernel symbol table starts here.
338 extern struct _dynamic _DYNAMIC;
341 link_elf_error(const char *filename, const char *s)
343 if (filename == NULL)
344 printf("kldload: %s\n", s);
346 printf("kldload: %s: %s\n", filename, s);
350 link_elf_invoke_ctors(caddr_t addr, size_t size)
355 if (addr == NULL || size == 0)
357 cnt = size / sizeof(*ctor);
359 for (i = 0; i < cnt; i++) {
366 * Actions performed after linking/loading both the preloaded kernel and any
367 * modules; whether preloaded or dynamicly loaded.
370 link_elf_link_common_finish(linker_file_t lf)
373 elf_file_t ef = (elf_file_t)lf;
378 /* Notify MD code that a module is being loaded. */
379 error = elf_cpu_load_file(lf);
385 ef->gdb.l_addr = lf->address;
386 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
387 strcpy(newfilename, lf->filename);
388 ef->gdb.l_name = newfilename;
389 ef->gdb.l_ld = ef->dynamic;
390 link_elf_add_gdb(&ef->gdb);
391 GDB_STATE(RT_CONSISTENT);
395 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
399 #ifdef RELOCATABLE_KERNEL
401 * __startkernel and __endkernel are symbols set up as relocation canaries.
403 * They are defined in locore to reference linker script symbols at the
404 * beginning and end of the LOAD area. This has the desired side effect of
405 * giving us variables that have relative relocations pointing at them, so
406 * relocation of the kernel object will cause the variables to be updated
407 * automatically by the runtime linker when we initialize.
409 * There are two main reasons to relocate the kernel:
410 * 1) If the loader needed to load the kernel at an alternate load address.
411 * 2) If the kernel is switching address spaces on machines like POWER9
412 * under Radix where the high bits of the effective address are used to
413 * differentiate between hypervisor, host, guest, and problem state.
415 extern vm_offset_t __startkernel, __endkernel;
418 static unsigned long kern_relbase = KERNBASE;
420 SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD,
421 SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address");
422 SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD,
423 &kern_relbase, 0, "Kernel relocated base address");
426 link_elf_init(void* arg)
429 Elf_Addr *ctors_addrp;
430 Elf_Size *ctors_sizep;
431 caddr_t modptr, baseptr, sizeptr;
435 linker_add_class(&link_elf_class);
437 dp = (Elf_Dyn *)&_DYNAMIC;
439 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
441 modptr = preload_search_by_type("elf kernel");
442 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
445 linker_kernel_file = linker_make_file(modname, &link_elf_class);
446 if (linker_kernel_file == NULL)
447 panic("%s: Can't create linker structures for kernel",
450 ef = (elf_file_t) linker_kernel_file;
452 #ifdef RELOCATABLE_KERNEL
453 /* Compute relative displacement */
454 ef->address = (caddr_t) (__startkernel - KERNBASE);
458 #ifdef SPARSE_MAPPING
465 #ifdef RELOCATABLE_KERNEL
466 linker_kernel_file->address = (caddr_t)__startkernel;
467 linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
468 kern_relbase = (unsigned long)__startkernel;
470 linker_kernel_file->address += KERNBASE;
471 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
474 if (modptr != NULL) {
476 baseptr = preload_search_info(modptr, MODINFO_ADDR);
478 linker_kernel_file->address = *(caddr_t *)baseptr;
479 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
481 linker_kernel_file->size = *(size_t *)sizeptr;
482 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
483 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
484 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
485 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
486 if (ctors_addrp != NULL && ctors_sizep != NULL) {
487 linker_kernel_file->ctors_addr = ef->address +
489 linker_kernel_file->ctors_size = *ctors_sizep;
492 (void)link_elf_preload_parse_symbols(ef);
495 r_debug.r_map = NULL;
496 r_debug.r_brk = r_debug_state;
497 r_debug.r_state = RT_CONSISTENT;
500 (void)link_elf_link_common_finish(linker_kernel_file);
501 linker_kernel_file->flags |= LINKER_FILE_LINKED;
502 TAILQ_INIT(&set_pcpu_list);
504 TAILQ_INIT(&set_vnet_list);
508 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL);
511 link_elf_preload_parse_symbols(elf_file_t ef)
514 caddr_t ssym, esym, base;
520 if (ef->modptr == NULL)
522 pointer = preload_search_info(ef->modptr,
523 MODINFO_METADATA | MODINFOMD_SSYM);
526 ssym = *(caddr_t *)pointer;
527 pointer = preload_search_info(ef->modptr,
528 MODINFO_METADATA | MODINFOMD_ESYM);
531 esym = *(caddr_t *)pointer;
535 symcnt = *(long *)base;
536 base += sizeof(long);
537 symtab = (Elf_Sym *)base;
538 base += roundup(symcnt, sizeof(long));
540 if (base > esym || base < ssym) {
541 printf("Symbols are corrupt!\n");
545 strcnt = *(long *)base;
546 base += sizeof(long);
548 base += roundup(strcnt, sizeof(long));
550 if (base > esym || base < ssym) {
551 printf("Symbols are corrupt!\n");
555 ef->ddbsymtab = symtab;
556 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
557 ef->ddbstrtab = strtab;
558 ef->ddbstrcnt = strcnt;
564 parse_dynamic(elf_file_t ef)
567 int plttype = DT_REL;
569 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
573 /* From src/libexec/rtld-elf/rtld.c */
574 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
575 (ef->address + dp->d_un.d_ptr);
576 ef->nbuckets = hashtab[0];
577 ef->nchains = hashtab[1];
578 ef->buckets = hashtab + 2;
579 ef->chains = ef->buckets + ef->nbuckets;
583 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
586 ef->strsz = dp->d_un.d_val;
589 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
592 if (dp->d_un.d_val != sizeof(Elf_Sym))
596 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
599 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
602 ef->relsize = dp->d_un.d_val;
605 if (dp->d_un.d_val != sizeof(Elf_Rel))
609 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
612 ef->pltrelsize = dp->d_un.d_val;
615 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
618 ef->relasize = dp->d_un.d_val;
621 if (dp->d_un.d_val != sizeof(Elf_Rela))
625 plttype = dp->d_un.d_val;
626 if (plttype != DT_REL && plttype != DT_RELA)
631 dp->d_un.d_ptr = (Elf_Addr)&r_debug;
637 if (plttype == DT_RELA) {
638 ef->pltrela = (const Elf_Rela *)ef->pltrel;
640 ef->pltrelasize = ef->pltrelsize;
644 ef->ddbsymtab = ef->symtab;
645 ef->ddbsymcnt = ef->nchains;
646 ef->ddbstrtab = ef->strtab;
647 ef->ddbstrcnt = ef->strsz;
649 return elf_cpu_parse_dynamic(ef->address, ef->dynamic);
652 #define LS_PADDING 0x90909090
654 parse_dpcpu(elf_file_t ef)
657 #if defined(__i386__)
663 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
664 (void ***)&ef->pcpu_stop, NULL);
665 /* Error just means there is no pcpu set to relocate. */
668 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start;
672 #if defined(__i386__)
673 /* In case we do find __start/stop_set_ symbols double-check. */
675 uprintf("Kernel module '%s' must be recompiled with "
676 "linker script\n", ef->lf.pathname);
680 /* Padding from linker-script correct? */
681 pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad));
682 if (pad != LS_PADDING) {
683 uprintf("Kernel module '%s' must be recompiled with "
684 "linker script, invalid padding %#04x (%#04x)\n",
685 ef->lf.pathname, pad, LS_PADDING);
688 /* If we only have valid padding, nothing to do. */
693 * Allocate space in the primary pcpu area. Copy in our
694 * initialization from the data section and then initialize
695 * all per-cpu storage from that.
697 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size);
698 if (ef->pcpu_base == 0) {
699 printf("%s: pcpu module space is out of space; "
700 "cannot allocate %d for %s\n",
701 __func__, size, ef->lf.pathname);
704 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size);
705 dpcpu_copy((void *)ef->pcpu_base, size);
706 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
714 parse_vnet(elf_file_t ef)
717 #if defined(__i386__)
723 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
724 (void ***)&ef->vnet_stop, NULL);
725 /* Error just means there is no vnet data set to relocate. */
728 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
732 #if defined(__i386__)
733 /* In case we do find __start/stop_set_ symbols double-check. */
735 uprintf("Kernel module '%s' must be recompiled with "
736 "linker script\n", ef->lf.pathname);
740 /* Padding from linker-script correct? */
741 pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad));
742 if (pad != LS_PADDING) {
743 uprintf("Kernel module '%s' must be recompiled with "
744 "linker script, invalid padding %#04x (%#04x)\n",
745 ef->lf.pathname, pad, LS_PADDING);
748 /* If we only have valid padding, nothing to do. */
753 * Allocate space in the primary vnet area. Copy in our
754 * initialization from the data section and then initialize
755 * all per-vnet storage from that.
757 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size);
758 if (ef->vnet_base == 0) {
759 printf("%s: vnet module space is out of space; "
760 "cannot allocate %d for %s\n",
761 __func__, size, ef->lf.pathname);
764 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size);
765 vnet_data_copy((void *)ef->vnet_base, size);
766 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
775 * Apply the specified protection to the loadable segments of a preloaded linker
779 preload_protect(elf_file_t ef, vm_prot_t prot)
781 #if defined(__aarch64__) || defined(__amd64__)
783 Elf_Phdr *phdr, *phlimit;
788 hdr = (Elf_Ehdr *)ef->address;
789 phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff);
790 phlimit = phdr + hdr->e_phnum;
791 for (; phdr < phlimit; phdr++) {
792 if (phdr->p_type != PT_LOAD)
795 nprot = prot | VM_PROT_READ;
796 if ((phdr->p_flags & PF_W) != 0)
797 nprot |= VM_PROT_WRITE;
798 if ((phdr->p_flags & PF_X) != 0)
799 nprot |= VM_PROT_EXECUTE;
800 error = pmap_change_prot((vm_offset_t)ef->address +
801 phdr->p_vaddr, round_page(phdr->p_memsz), nprot);
813 * Locate the ARM exception/unwind table info for DDB and stack(9) use by
814 * searching for the section header that describes it. There may be no unwind
815 * info, for example in a module containing only data.
818 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr)
822 for (i = 0; i < nhdr; i++) {
823 if (shdr[i].sh_type == SHT_ARM_EXIDX) {
824 lf->exidx_addr = shdr[i].sh_addr + lf->address;
825 lf->exidx_size = shdr[i].sh_size;
832 * Locate the section headers metadata in a preloaded module, then use it to
833 * locate the exception/unwind table in the module. The size of the metadata
834 * block is stored in a uint32 word immediately before the data itself, and a
835 * comment in preload_search_info() says it is safe to rely on that.
838 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr)
844 modinfo = (uint32_t *)preload_search_info(modptr,
845 MODINFO_METADATA | MODINFOMD_SHDR);
846 if (modinfo != NULL) {
847 shdr = (Elf_Shdr *)modinfo;
848 nhdr = modinfo[-1] / sizeof(Elf_Shdr);
849 link_elf_locate_exidx(lf, shdr, nhdr);
856 link_elf_link_preload(linker_class_t cls, const char *filename,
857 linker_file_t *result)
859 Elf_Addr *ctors_addrp;
860 Elf_Size *ctors_sizep;
861 caddr_t modptr, baseptr, sizeptr, dynptr;
868 /* Look to see if we have the file preloaded */
869 modptr = preload_search_by_name(filename);
873 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
874 baseptr = preload_search_info(modptr, MODINFO_ADDR);
875 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
876 dynptr = preload_search_info(modptr,
877 MODINFO_METADATA | MODINFOMD_DYNAMIC);
879 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
880 strcmp(type, "elf module") != 0))
882 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
885 lf = linker_make_file(filename, &link_elf_class);
889 ef = (elf_file_t) lf;
892 ef->address = *(caddr_t *)baseptr;
893 #ifdef SPARSE_MAPPING
896 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
897 ef->dynamic = (Elf_Dyn *)dp;
898 lf->address = ef->address;
899 lf->size = *(size_t *)sizeptr;
901 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
902 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
903 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
904 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
905 if (ctors_addrp != NULL && ctors_sizep != NULL) {
906 lf->ctors_addr = ef->address + *ctors_addrp;
907 lf->ctors_size = *ctors_sizep;
911 link_elf_locate_exidx_preload(lf, modptr);
914 error = parse_dynamic(ef);
916 error = parse_dpcpu(ef);
919 error = parse_vnet(ef);
922 error = preload_protect(ef, VM_PROT_ALL);
924 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
927 link_elf_reloc_local(lf);
933 link_elf_link_preload_finish(linker_file_t lf)
938 ef = (elf_file_t) lf;
939 error = relocate_file(ef);
941 error = preload_protect(ef, VM_PROT_NONE);
944 (void)link_elf_preload_parse_symbols(ef);
946 return (link_elf_link_common_finish(lf));
950 link_elf_load_file(linker_class_t cls, const char* filename,
951 linker_file_t* result)
954 struct thread* td = curthread; /* XXX */
956 caddr_t firstpage, segbase;
960 Elf_Phdr *segs[MAXSEGS];
966 Elf_Addr base_vlimit;
984 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
986 error = vn_open(&nd, &flags, 0, NULL);
989 NDFREE(&nd, NDF_ONLY_PNBUF);
990 if (nd.ni_vp->v_type != VREG) {
996 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
1004 * Read the elf header from the file.
1006 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
1007 hdr = (Elf_Ehdr *)firstpage;
1008 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
1009 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1011 nbytes = PAGE_SIZE - resid;
1015 if (!IS_ELF(*hdr)) {
1020 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
1021 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
1022 link_elf_error(filename, "Unsupported file layout");
1026 if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
1027 hdr->e_version != EV_CURRENT) {
1028 link_elf_error(filename, "Unsupported file version");
1032 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
1036 if (hdr->e_machine != ELF_TARG_MACH) {
1037 link_elf_error(filename, "Unsupported machine");
1043 * We rely on the program header being in the first page.
1044 * This is not strictly required by the ABI specification, but
1045 * it seems to always true in practice. And, it simplifies
1046 * things considerably.
1048 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
1049 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
1050 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
1051 link_elf_error(filename, "Unreadable program headers");
1054 * Scan the program header entries, and save key information.
1056 * We rely on there being exactly two load segments, text and data,
1059 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
1060 phlimit = phdr + hdr->e_phnum;
1063 while (phdr < phlimit) {
1064 switch (phdr->p_type) {
1066 if (nsegs == MAXSEGS) {
1067 link_elf_error(filename, "Too many sections");
1072 * XXX: We just trust they come in right order ??
1089 if (phdyn == NULL) {
1090 link_elf_error(filename, "Object is not dynamically-linked");
1095 link_elf_error(filename, "No sections");
1101 * Allocate the entire address space of the object, to stake
1102 * out our contiguous region, and to establish the base
1103 * address for relocation.
1105 base_vaddr = trunc_page(segs[0]->p_vaddr);
1106 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
1107 segs[nsegs - 1]->p_memsz);
1108 mapsize = base_vlimit - base_vaddr;
1110 lf = linker_make_file(filename, &link_elf_class);
1116 ef = (elf_file_t) lf;
1117 #ifdef SPARSE_MAPPING
1118 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, mapsize, VM_PROT_ALL,
1119 0, thread0.td_ucred);
1120 if (ef->object == NULL) {
1125 mapbase = (caddr_t)KERNBASE;
1127 mapbase = (caddr_t)vm_map_min(kernel_map);
1130 * Mapping protections are downgraded after relocation processing.
1132 error = vm_map_find(kernel_map, ef->object, 0,
1133 (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE,
1134 VM_PROT_ALL, VM_PROT_ALL, 0);
1136 vm_object_deallocate(ef->object);
1141 mapbase = malloc_exec(mapsize, M_LINKER, M_WAITOK);
1143 ef->address = mapbase;
1146 * Read the text and data sections and zero the bss.
1148 for (i = 0; i < nsegs; i++) {
1149 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1151 #ifdef SPARSE_MAPPING
1153 * Consecutive segments may have different mapping permissions,
1154 * so be strict and verify that their mappings do not overlap.
1156 if (((vm_offset_t)segbase & PAGE_MASK) != 0) {
1161 error = vm_map_wire(kernel_map,
1162 (vm_offset_t)segbase,
1163 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1164 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
1165 if (error != KERN_SUCCESS) {
1171 error = vn_rdwr(UIO_READ, nd.ni_vp,
1172 segbase, segs[i]->p_filesz, segs[i]->p_offset,
1173 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1177 bzero(segbase + segs[i]->p_filesz,
1178 segs[i]->p_memsz - segs[i]->p_filesz);
1182 /* Update profiling information with the new text segment. */
1184 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
1189 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
1191 lf->address = ef->address;
1194 error = parse_dynamic(ef);
1197 error = parse_dpcpu(ef);
1201 error = parse_vnet(ef);
1205 link_elf_reloc_local(lf);
1207 VOP_UNLOCK(nd.ni_vp);
1208 error = linker_load_dependencies(lf);
1209 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1212 error = relocate_file(ef);
1216 #ifdef SPARSE_MAPPING
1218 * Downgrade permissions on text segment mappings now that relocation
1219 * processing is complete. Restrict permissions on read-only segments.
1221 for (i = 0; i < nsegs; i++) {
1224 if (segs[i]->p_type != PT_LOAD)
1227 prot = VM_PROT_READ;
1228 if ((segs[i]->p_flags & PF_W) != 0)
1229 prot |= VM_PROT_WRITE;
1230 if ((segs[i]->p_flags & PF_X) != 0)
1231 prot |= VM_PROT_EXECUTE;
1232 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1233 error = vm_map_protect(kernel_map,
1234 (vm_offset_t)segbase,
1235 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1236 prot, 0, VM_MAP_PROTECT_SET_PROT);
1237 if (error != KERN_SUCCESS) {
1245 * Try and load the symbol table if it's present. (you can
1248 nbytes = hdr->e_shnum * hdr->e_shentsize;
1249 if (nbytes == 0 || hdr->e_shoff == 0)
1251 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1252 error = vn_rdwr(UIO_READ, nd.ni_vp,
1253 (caddr_t)shdr, nbytes, hdr->e_shoff,
1254 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1259 /* Read section string table */
1260 shstrindex = hdr->e_shstrndx;
1261 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1262 shdr[shstrindex].sh_size != 0) {
1263 nbytes = shdr[shstrindex].sh_size;
1264 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1265 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1266 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1267 td->td_ucred, NOCRED, &resid, td);
1274 for (i = 0; i < hdr->e_shnum; i++) {
1275 if (shdr[i].sh_type == SHT_SYMTAB) {
1277 symstrindex = shdr[i].sh_link;
1278 } else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1279 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1280 /* Record relocated address and size of .ctors. */
1281 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1282 lf->ctors_size = shdr[i].sh_size;
1285 if (symtabindex < 0 || symstrindex < 0)
1288 symcnt = shdr[symtabindex].sh_size;
1289 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1290 strcnt = shdr[symstrindex].sh_size;
1291 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1293 error = vn_rdwr(UIO_READ, nd.ni_vp,
1294 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1295 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1299 error = vn_rdwr(UIO_READ, nd.ni_vp,
1300 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1301 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1306 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1307 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1308 ef->ddbstrcnt = strcnt;
1309 ef->ddbstrtab = ef->strbase;
1314 link_elf_locate_exidx(lf, shdr, hdr->e_shnum);
1317 error = link_elf_link_common_finish(lf);
1324 VOP_UNLOCK(nd.ni_vp);
1325 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1326 if (error != 0 && lf != NULL)
1327 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1328 free(shdr, M_LINKER);
1329 free(firstpage, M_LINKER);
1330 free(shstrs, M_LINKER);
1336 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1340 KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class,
1341 ("elf_relocaddr: unexpected linker file %p", lf));
1343 ef = (elf_file_t)lf;
1344 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1345 return ((x - ef->pcpu_start) + ef->pcpu_base);
1347 if (x >= ef->vnet_start && x < ef->vnet_stop)
1348 return ((x - ef->vnet_start) + ef->vnet_base);
1354 link_elf_unload_file(linker_file_t file)
1356 elf_file_t ef = (elf_file_t) file;
1358 if (ef->pcpu_base != 0) {
1359 dpcpu_free((void *)ef->pcpu_base,
1360 ef->pcpu_stop - ef->pcpu_start);
1361 elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1364 if (ef->vnet_base != 0) {
1365 vnet_data_free((void *)ef->vnet_base,
1366 ef->vnet_stop - ef->vnet_start);
1367 elf_set_delete(&set_vnet_list, ef->vnet_start);
1371 if (ef->gdb.l_ld != NULL) {
1372 GDB_STATE(RT_DELETE);
1373 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1374 link_elf_delete_gdb(&ef->gdb);
1375 GDB_STATE(RT_CONSISTENT);
1379 /* Notify MD code that a module is being unloaded. */
1380 elf_cpu_unload_file(file);
1382 if (ef->preloaded) {
1383 link_elf_unload_preload(file);
1387 #ifdef SPARSE_MAPPING
1388 if (ef->object != NULL) {
1389 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1390 (vm_offset_t) ef->address
1391 + (ef->object->size << PAGE_SHIFT));
1394 free(ef->address, M_LINKER);
1396 free(ef->symbase, M_LINKER);
1397 free(ef->strbase, M_LINKER);
1398 free(ef->ctftab, M_LINKER);
1399 free(ef->ctfoff, M_LINKER);
1400 free(ef->typoff, M_LINKER);
1404 link_elf_unload_preload(linker_file_t file)
1407 if (file->pathname != NULL)
1408 preload_delete_name(file->pathname);
1412 symbol_name(elf_file_t ef, Elf_Size r_info)
1416 if (ELF_R_SYM(r_info)) {
1417 ref = ef->symtab + ELF_R_SYM(r_info);
1418 return (ef->strtab + ref->st_name);
1424 symbol_type(elf_file_t ef, Elf_Size r_info)
1428 if (ELF_R_SYM(r_info)) {
1429 ref = ef->symtab + ELF_R_SYM(r_info);
1430 return (ELF_ST_TYPE(ref->st_info));
1432 return (STT_NOTYPE);
1436 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc,
1440 const Elf_Rela *rela;
1441 const char *symname;
1443 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \
1444 for ((iter) = (tbl); (iter) != NULL && \
1445 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \
1446 if ((symbol_type(ef, (iter)->r_info) == \
1448 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \
1450 if (reloc(&ef->lf, (Elf_Addr)ef->address, \
1451 (iter), (type), lookup)) { \
1452 symname = symbol_name(ef, (iter)->r_info); \
1453 printf("link_elf: symbol %s undefined\n", \
1460 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL);
1461 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA);
1462 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL);
1463 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA);
1471 relocate_file(elf_file_t ef)
1475 error = relocate_file1(ef, elf_lookup, elf_reloc, false);
1477 error = relocate_file1(ef, elf_lookup, elf_reloc, true);
1482 * SysV hash function for symbol table lookup. It is specified by the
1486 elf_hash(const char *name)
1488 const unsigned char *p = (const unsigned char *)name;
1491 while (*p != '\0') {
1492 h = (h << 4) + *p++;
1493 h ^= (h >> 24) & 0xf0;
1495 return (h & 0x0fffffff);
1499 link_elf_lookup_symbol1(linker_file_t lf, const char *name, c_linker_sym_t *sym,
1502 elf_file_t ef = (elf_file_t) lf;
1503 unsigned long symnum;
1504 const Elf_Sym* symp;
1508 /* If we don't have a hash, bail. */
1509 if (ef->buckets == NULL || ef->nbuckets == 0) {
1510 printf("link_elf_lookup_symbol: missing symbol hash table\n");
1514 /* First, search hashed global symbols */
1515 hash = elf_hash(name);
1516 symnum = ef->buckets[hash % ef->nbuckets];
1518 while (symnum != STN_UNDEF) {
1519 if (symnum >= ef->nchains) {
1520 printf("%s: corrupt symbol table\n", __func__);
1524 symp = ef->symtab + symnum;
1525 if (symp->st_name == 0) {
1526 printf("%s: corrupt symbol table\n", __func__);
1530 strp = ef->strtab + symp->st_name;
1532 if (strcmp(name, strp) == 0) {
1533 if (symp->st_shndx != SHN_UNDEF ||
1534 (symp->st_value != 0 &&
1535 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1536 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1538 ELF_ST_BIND(symp->st_info) != STB_LOCAL) {
1539 *sym = (c_linker_sym_t) symp;
1546 symnum = ef->chains[symnum];
1553 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1555 if (link_elf_leak_locals)
1556 return (link_elf_lookup_debug_symbol(lf, name, sym));
1557 return (link_elf_lookup_symbol1(lf, name, sym, false));
1561 link_elf_lookup_debug_symbol(linker_file_t lf, const char *name,
1562 c_linker_sym_t *sym)
1564 elf_file_t ef = (elf_file_t)lf;
1565 const Elf_Sym* symp;
1569 if (link_elf_lookup_symbol1(lf, name, sym, true) == 0)
1572 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1573 strp = ef->ddbstrtab + symp->st_name;
1574 if (strcmp(name, strp) == 0) {
1575 if (symp->st_shndx != SHN_UNDEF ||
1576 (symp->st_value != 0 &&
1577 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1578 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1579 *sym = (c_linker_sym_t) symp;
1590 link_elf_symbol_values1(linker_file_t lf, c_linker_sym_t sym,
1591 linker_symval_t *symval, bool see_local)
1597 ef = (elf_file_t)lf;
1598 es = (const Elf_Sym *)sym;
1599 if (es >= ef->symtab && es < ef->symtab + ef->nchains) {
1600 if (!see_local && ELF_ST_BIND(es->st_info) == STB_LOCAL)
1602 symval->name = ef->strtab + es->st_name;
1603 val = (caddr_t)ef->address + es->st_value;
1604 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1605 val = ((caddr_t (*)(void))val)();
1606 symval->value = val;
1607 symval->size = es->st_size;
1614 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1615 linker_symval_t *symval)
1617 if (link_elf_leak_locals)
1618 return (link_elf_debug_symbol_values(lf, sym, symval));
1619 return (link_elf_symbol_values1(lf, sym, symval, false));
1623 link_elf_debug_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1624 linker_symval_t *symval)
1626 elf_file_t ef = (elf_file_t)lf;
1627 const Elf_Sym *es = (const Elf_Sym *)sym;
1630 if (link_elf_symbol_values1(lf, sym, symval, true) == 0)
1632 if (ef->symtab == ef->ddbsymtab)
1635 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1636 symval->name = ef->ddbstrtab + es->st_name;
1637 val = (caddr_t)ef->address + es->st_value;
1638 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1639 val = ((caddr_t (*)(void))val)();
1640 symval->value = val;
1641 symval->size = es->st_size;
1648 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1649 c_linker_sym_t *sym, long *diffp)
1651 elf_file_t ef = (elf_file_t)lf;
1652 u_long off = (uintptr_t)(void *)value;
1656 const Elf_Sym *best = NULL;
1659 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1660 if (es->st_name == 0)
1662 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1663 if (off >= st_value) {
1664 if (off - st_value < diff) {
1665 diff = off - st_value;
1669 } else if (off - st_value == diff) {
1678 *sym = (c_linker_sym_t) best;
1684 * Look up a linker set on an ELF system.
1687 link_elf_lookup_set(linker_file_t lf, const char *name,
1688 void ***startp, void ***stopp, int *countp)
1691 linker_symval_t symval;
1693 void **start, **stop;
1694 int len, error = 0, count;
1696 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1697 setsym = malloc(len, M_LINKER, M_WAITOK);
1699 /* get address of first entry */
1700 snprintf(setsym, len, "%s%s", "__start_set_", name);
1701 error = link_elf_lookup_symbol(lf, setsym, &sym);
1704 link_elf_symbol_values(lf, sym, &symval);
1705 if (symval.value == 0) {
1709 start = (void **)symval.value;
1711 /* get address of last entry */
1712 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1713 error = link_elf_lookup_symbol(lf, setsym, &sym);
1716 link_elf_symbol_values(lf, sym, &symval);
1717 if (symval.value == 0) {
1721 stop = (void **)symval.value;
1723 /* and the number of entries */
1724 count = stop - start;
1735 free(setsym, M_LINKER);
1740 link_elf_each_function_name(linker_file_t file,
1741 int (*callback)(const char *, void *), void *opaque)
1743 elf_file_t ef = (elf_file_t)file;
1744 const Elf_Sym *symp;
1747 /* Exhaustive search */
1748 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1749 if (symp->st_value != 0 &&
1750 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1751 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1752 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1761 link_elf_each_function_nameval(linker_file_t file,
1762 linker_function_nameval_callback_t callback, void *opaque)
1764 linker_symval_t symval;
1765 elf_file_t ef = (elf_file_t)file;
1766 const Elf_Sym *symp;
1769 /* Exhaustive search */
1770 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1771 if (symp->st_value != 0 &&
1772 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1773 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1774 error = link_elf_debug_symbol_values(file,
1775 (c_linker_sym_t) symp, &symval);
1777 error = callback(file, i, &symval, opaque);
1786 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1788 elf_file_t ef = (elf_file_t)lf;
1790 if (symidx >= ef->nchains)
1792 return (ef->symtab + symidx);
1796 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1798 elf_file_t ef = (elf_file_t)lf;
1801 if (symidx >= ef->nchains)
1803 sym = ef->symtab + symidx;
1804 return (ef->strtab + sym->st_name);
1808 * Symbol lookup function that can be used when the symbol index is known (ie
1809 * in relocations). It uses the symbol index instead of doing a fully fledged
1810 * hash table based lookup when such is valid. For example for local symbols.
1811 * This is not only more efficient, it's also more correct. It's not always
1812 * the case that the symbol can be found through the hash table.
1815 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1817 elf_file_t ef = (elf_file_t)lf;
1820 Elf_Addr addr, start, base;
1822 /* Don't even try to lookup the symbol if the index is bogus. */
1823 if (symidx >= ef->nchains) {
1828 sym = ef->symtab + symidx;
1831 * Don't do a full lookup when the symbol is local. It may even
1832 * fail because it may not be found through the hash table.
1834 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1835 /* Force lookup failure when we have an insanity. */
1836 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1840 *res = ((Elf_Addr)ef->address + sym->st_value);
1845 * XXX we can avoid doing a hash table based lookup for global
1846 * symbols as well. This however is not always valid, so we'll
1847 * just do it the hard way for now. Performance tweaks can
1851 symbol = ef->strtab + sym->st_name;
1853 /* Force a lookup failure if the symbol name is bogus. */
1859 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1860 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1865 if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1866 addr = addr - start + base;
1868 else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1869 addr = addr - start + base;
1876 link_elf_reloc_local(linker_file_t lf)
1878 const Elf_Rel *rellim;
1880 const Elf_Rela *relalim;
1881 const Elf_Rela *rela;
1882 elf_file_t ef = (elf_file_t)lf;
1884 /* Perform relocations without addend if there are any: */
1885 if ((rel = ef->rel) != NULL) {
1886 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1887 while (rel < rellim) {
1888 elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1889 ELF_RELOC_REL, elf_lookup);
1894 /* Perform relocations with addend if there are any: */
1895 if ((rela = ef->rela) != NULL) {
1896 relalim = (const Elf_Rela *)
1897 ((const char *)ef->rela + ef->relasize);
1898 while (rela < relalim) {
1899 elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1900 ELF_RELOC_RELA, elf_lookup);
1907 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1909 elf_file_t ef = (elf_file_t)lf;
1911 *symtab = ef->ddbsymtab;
1913 if (*symtab == NULL)
1916 return (ef->ddbsymcnt);
1920 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1922 elf_file_t ef = (elf_file_t)lf;
1924 *strtab = ef->ddbstrtab;
1926 if (*strtab == NULL)
1929 return (ef->ddbstrcnt);
1932 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) || defined(__powerpc__)
1934 * Use this lookup routine when performing relocations early during boot.
1935 * The generic lookup routine depends on kobj, which is not initialized
1939 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused,
1943 const Elf_Sym *symp;
1946 ef = (elf_file_t)lf;
1947 symp = ef->symtab + symidx;
1948 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) {
1949 val = (caddr_t)ef->address + symp->st_value;
1950 *res = ((Elf_Addr (*)(void))val)();
1957 link_elf_ireloc(caddr_t kmdp)
1959 struct elf_file eff;
1964 bzero_early(ef, sizeof(*ef));
1967 ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
1969 #ifdef RELOCATABLE_KERNEL
1970 ef->address = (caddr_t) (__startkernel - KERNBASE);
1976 link_elf_preload_parse_symbols(ef);
1977 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true);
1980 #if defined(__aarch64__) || defined(__amd64__)
1982 link_elf_late_ireloc(void)
1986 KASSERT(linker_kernel_file != NULL,
1987 ("link_elf_late_ireloc: No kernel linker file found"));
1988 ef = (elf_file_t)linker_kernel_file;
1990 relocate_file1(ef, elf_lookup_ifunc, elf_reloc_late, true);