2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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>
30 __FBSDID("$FreeBSD$");
35 #include <sys/param.h>
36 #include <sys/systm.h>
40 #include <sys/kernel.h>
42 #include <sys/malloc.h>
46 #include <sys/mutex.h>
47 #include <sys/mount.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>
56 #include <machine/elf.h>
60 #include <security/mac/mac_framework.h>
63 #include <vm/vm_param.h>
65 #include <vm/vm_object.h>
66 #include <vm/vm_kern.h>
67 #include <vm/vm_extern.h>
70 #include <vm/vm_map.h>
72 #include <sys/link_elf.h>
74 #include "linker_if.h"
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 */
83 vm_object_t object; /* VM object to hold file pages */
85 Elf_Dyn *dynamic; /* Symbol table etc. */
86 Elf_Hashelt nbuckets; /* DT_HASH info */
88 const Elf_Hashelt *buckets;
89 const Elf_Hashelt *chains;
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 */
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. */
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. */
124 struct link_map gdb; /* hooks for gdb */
132 TAILQ_ENTRY(elf_set) es_link;
135 TAILQ_HEAD(elf_set_head, elf_set);
137 #include <kern/kern_ctf.c>
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 *,
145 static int link_elf_lookup_symbol(linker_file_t, const char *,
147 static int link_elf_lookup_debug_symbol(linker_file_t, const char *,
149 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
151 static int link_elf_debug_symbol_values(linker_file_t, c_linker_sym_t,
153 static int link_elf_search_symbol(linker_file_t, caddr_t,
154 c_linker_sym_t *, long *);
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 *);
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),
188 static struct linker_class link_elf_class = {
189 #if ELF_TARG_CLASS == ELFCLASS32
194 link_elf_methods, sizeof(struct elf_file)
197 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase,
198 const void *data, int type, elf_lookup_fn lookup);
200 static int parse_dynamic(elf_file_t);
201 static int relocate_file(elf_file_t);
202 static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup,
203 elf_reloc_fn reloc, bool ifuncs);
204 static int link_elf_preload_parse_symbols(elf_file_t);
206 static struct elf_set_head set_pcpu_list;
208 static struct elf_set_head set_vnet_list;
212 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
214 struct elf_set *set, *iter;
216 set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
217 set->es_start = start;
221 TAILQ_FOREACH(iter, list, es_link) {
222 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
223 (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
224 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
225 (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
226 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
228 if (iter->es_start > set->es_start) {
229 TAILQ_INSERT_BEFORE(iter, set, es_link);
235 TAILQ_INSERT_TAIL(list, set, es_link);
239 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
243 TAILQ_FOREACH(set, list, es_link) {
244 if (addr < set->es_start)
246 if (addr < set->es_stop) {
247 *start = set->es_start;
248 *base = set->es_base;
257 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
261 TAILQ_FOREACH(set, list, es_link) {
262 if (start < set->es_start)
264 if (start == set->es_start) {
265 TAILQ_REMOVE(list, set, es_link);
270 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
275 static void r_debug_state(struct r_debug *, struct link_map *);
278 * A list of loaded modules for GDB to use for loading symbols.
280 struct r_debug r_debug;
282 #define GDB_STATE(s) do { \
283 r_debug.r_state = s; r_debug_state(NULL, NULL); \
287 * Function for the debugger to set a breakpoint on to gain control.
290 r_debug_state(struct r_debug *dummy_one __unused,
291 struct link_map *dummy_two __unused)
296 link_elf_add_gdb(struct link_map *l)
298 struct link_map *prev;
302 if (r_debug.r_map == NULL) {
307 /* Append to list. */
308 for (prev = r_debug.r_map;
309 prev->l_next != NULL;
318 link_elf_delete_gdb(struct link_map *l)
320 if (l->l_prev == NULL) {
322 if ((r_debug.r_map = l->l_next) != NULL)
323 l->l_next->l_prev = NULL;
325 /* Remove any but first. */
326 if ((l->l_prev->l_next = l->l_next) != NULL)
327 l->l_next->l_prev = l->l_prev;
333 * The kernel symbol table starts here.
335 extern struct _dynamic _DYNAMIC;
338 link_elf_error(const char *filename, const char *s)
340 if (filename == NULL)
341 printf("kldload: %s\n", s);
343 printf("kldload: %s: %s\n", filename, s);
347 link_elf_invoke_ctors(caddr_t addr, size_t size)
352 if (addr == NULL || size == 0)
354 cnt = size / sizeof(*ctor);
356 for (i = 0; i < cnt; i++) {
363 * Actions performed after linking/loading both the preloaded kernel and any
364 * modules; whether preloaded or dynamicly loaded.
367 link_elf_link_common_finish(linker_file_t lf)
370 elf_file_t ef = (elf_file_t)lf;
375 /* Notify MD code that a module is being loaded. */
376 error = elf_cpu_load_file(lf);
382 ef->gdb.l_addr = lf->address;
383 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
384 strcpy(newfilename, lf->filename);
385 ef->gdb.l_name = newfilename;
386 ef->gdb.l_ld = ef->dynamic;
387 link_elf_add_gdb(&ef->gdb);
388 GDB_STATE(RT_CONSISTENT);
392 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
396 #ifdef RELOCATABLE_KERNEL
398 * __startkernel and __endkernel are symbols set up as relocation canaries.
400 * They are defined in locore to reference linker script symbols at the
401 * beginning and end of the LOAD area. This has the desired side effect of
402 * giving us variables that have relative relocations pointing at them, so
403 * relocation of the kernel object will cause the variables to be updated
404 * automatically by the runtime linker when we initialize.
406 * There are two main reasons to relocate the kernel:
407 * 1) If the loader needed to load the kernel at an alternate load address.
408 * 2) If the kernel is switching address spaces on machines like POWER9
409 * under Radix where the high bits of the effective address are used to
410 * differentiate between hypervisor, host, guest, and problem state.
412 extern vm_offset_t __startkernel, __endkernel;
415 static unsigned long kern_relbase = KERNBASE;
417 SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD,
418 SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address");
419 SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD,
420 &kern_relbase, 0, "Kernel relocated base address");
423 link_elf_init(void* arg)
426 Elf_Addr *ctors_addrp;
427 Elf_Size *ctors_sizep;
428 caddr_t modptr, baseptr, sizeptr;
432 linker_add_class(&link_elf_class);
434 dp = (Elf_Dyn *)&_DYNAMIC;
436 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
438 modptr = preload_search_by_type("elf kernel");
439 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
442 linker_kernel_file = linker_make_file(modname, &link_elf_class);
443 if (linker_kernel_file == NULL)
444 panic("%s: Can't create linker structures for kernel",
447 ef = (elf_file_t) linker_kernel_file;
449 #ifdef RELOCATABLE_KERNEL
450 /* Compute relative displacement */
451 ef->address = (caddr_t) (__startkernel - KERNBASE);
455 #ifdef SPARSE_MAPPING
462 #ifdef RELOCATABLE_KERNEL
463 linker_kernel_file->address = (caddr_t)__startkernel;
464 linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
465 kern_relbase = (unsigned long)__startkernel;
467 linker_kernel_file->address += KERNBASE;
468 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
471 if (modptr != NULL) {
473 baseptr = preload_search_info(modptr, MODINFO_ADDR);
475 linker_kernel_file->address = *(caddr_t *)baseptr;
476 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
478 linker_kernel_file->size = *(size_t *)sizeptr;
479 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
480 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
481 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
482 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
483 if (ctors_addrp != NULL && ctors_sizep != NULL) {
484 linker_kernel_file->ctors_addr = ef->address +
486 linker_kernel_file->ctors_size = *ctors_sizep;
489 (void)link_elf_preload_parse_symbols(ef);
492 r_debug.r_map = NULL;
493 r_debug.r_brk = r_debug_state;
494 r_debug.r_state = RT_CONSISTENT;
497 (void)link_elf_link_common_finish(linker_kernel_file);
498 linker_kernel_file->flags |= LINKER_FILE_LINKED;
499 TAILQ_INIT(&set_pcpu_list);
501 TAILQ_INIT(&set_vnet_list);
505 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL);
508 link_elf_preload_parse_symbols(elf_file_t ef)
511 caddr_t ssym, esym, base;
517 if (ef->modptr == NULL)
519 pointer = preload_search_info(ef->modptr,
520 MODINFO_METADATA | MODINFOMD_SSYM);
523 ssym = *(caddr_t *)pointer;
524 pointer = preload_search_info(ef->modptr,
525 MODINFO_METADATA | MODINFOMD_ESYM);
528 esym = *(caddr_t *)pointer;
532 symcnt = *(long *)base;
533 base += sizeof(long);
534 symtab = (Elf_Sym *)base;
535 base += roundup(symcnt, sizeof(long));
537 if (base > esym || base < ssym) {
538 printf("Symbols are corrupt!\n");
542 strcnt = *(long *)base;
543 base += sizeof(long);
545 base += roundup(strcnt, sizeof(long));
547 if (base > esym || base < ssym) {
548 printf("Symbols are corrupt!\n");
552 ef->ddbsymtab = symtab;
553 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
554 ef->ddbstrtab = strtab;
555 ef->ddbstrcnt = strcnt;
561 parse_dynamic(elf_file_t ef)
564 int plttype = DT_REL;
566 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
570 /* From src/libexec/rtld-elf/rtld.c */
571 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
572 (ef->address + dp->d_un.d_ptr);
573 ef->nbuckets = hashtab[0];
574 ef->nchains = hashtab[1];
575 ef->buckets = hashtab + 2;
576 ef->chains = ef->buckets + ef->nbuckets;
580 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
583 ef->strsz = dp->d_un.d_val;
586 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
589 if (dp->d_un.d_val != sizeof(Elf_Sym))
593 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
596 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
599 ef->relsize = dp->d_un.d_val;
602 if (dp->d_un.d_val != sizeof(Elf_Rel))
606 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
609 ef->pltrelsize = dp->d_un.d_val;
612 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
615 ef->relasize = dp->d_un.d_val;
618 if (dp->d_un.d_val != sizeof(Elf_Rela))
622 plttype = dp->d_un.d_val;
623 if (plttype != DT_REL && plttype != DT_RELA)
628 dp->d_un.d_ptr = (Elf_Addr)&r_debug;
634 if (plttype == DT_RELA) {
635 ef->pltrela = (const Elf_Rela *)ef->pltrel;
637 ef->pltrelasize = ef->pltrelsize;
641 ef->ddbsymtab = ef->symtab;
642 ef->ddbsymcnt = ef->nchains;
643 ef->ddbstrtab = ef->strtab;
644 ef->ddbstrcnt = ef->strsz;
646 return elf_cpu_parse_dynamic(ef->address, ef->dynamic);
649 #define LS_PADDING 0x90909090
651 parse_dpcpu(elf_file_t ef)
654 #if defined(__i386__)
660 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
661 (void ***)&ef->pcpu_stop, NULL);
662 /* Error just means there is no pcpu set to relocate. */
665 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start;
669 #if defined(__i386__)
670 /* In case we do find __start/stop_set_ symbols double-check. */
672 uprintf("Kernel module '%s' must be recompiled with "
673 "linker script\n", ef->lf.pathname);
677 /* Padding from linker-script correct? */
678 pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad));
679 if (pad != LS_PADDING) {
680 uprintf("Kernel module '%s' must be recompiled with "
681 "linker script, invalid padding %#04x (%#04x)\n",
682 ef->lf.pathname, pad, LS_PADDING);
685 /* If we only have valid padding, nothing to do. */
690 * Allocate space in the primary pcpu area. Copy in our
691 * initialization from the data section and then initialize
692 * all per-cpu storage from that.
694 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size);
695 if (ef->pcpu_base == 0) {
696 printf("%s: pcpu module space is out of space; "
697 "cannot allocate %d for %s\n",
698 __func__, size, ef->lf.pathname);
701 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size);
702 dpcpu_copy((void *)ef->pcpu_base, size);
703 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
711 parse_vnet(elf_file_t ef)
714 #if defined(__i386__)
720 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
721 (void ***)&ef->vnet_stop, NULL);
722 /* Error just means there is no vnet data set to relocate. */
725 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
729 #if defined(__i386__)
730 /* In case we do find __start/stop_set_ symbols double-check. */
732 uprintf("Kernel module '%s' must be recompiled with "
733 "linker script\n", ef->lf.pathname);
737 /* Padding from linker-script correct? */
738 pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad));
739 if (pad != LS_PADDING) {
740 uprintf("Kernel module '%s' must be recompiled with "
741 "linker script, invalid padding %#04x (%#04x)\n",
742 ef->lf.pathname, pad, LS_PADDING);
745 /* If we only have valid padding, nothing to do. */
750 * Allocate space in the primary vnet area. Copy in our
751 * initialization from the data section and then initialize
752 * all per-vnet storage from that.
754 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size);
755 if (ef->vnet_base == 0) {
756 printf("%s: vnet module space is out of space; "
757 "cannot allocate %d for %s\n",
758 __func__, size, ef->lf.pathname);
761 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size);
762 vnet_data_copy((void *)ef->vnet_base, size);
763 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
772 * Apply the specified protection to the loadable segments of a preloaded linker
776 preload_protect(elf_file_t ef, vm_prot_t prot)
778 #if defined(__aarch64__) || defined(__amd64__)
780 Elf_Phdr *phdr, *phlimit;
785 hdr = (Elf_Ehdr *)ef->address;
786 phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff);
787 phlimit = phdr + hdr->e_phnum;
788 for (; phdr < phlimit; phdr++) {
789 if (phdr->p_type != PT_LOAD)
792 nprot = prot | VM_PROT_READ;
793 if ((phdr->p_flags & PF_W) != 0)
794 nprot |= VM_PROT_WRITE;
795 if ((phdr->p_flags & PF_X) != 0)
796 nprot |= VM_PROT_EXECUTE;
797 error = pmap_change_prot((vm_offset_t)ef->address +
798 phdr->p_vaddr, round_page(phdr->p_memsz), nprot);
810 * Locate the ARM exception/unwind table info for DDB and stack(9) use by
811 * searching for the section header that describes it. There may be no unwind
812 * info, for example in a module containing only data.
815 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr)
819 for (i = 0; i < nhdr; i++) {
820 if (shdr[i].sh_type == SHT_ARM_EXIDX) {
821 lf->exidx_addr = shdr[i].sh_addr + lf->address;
822 lf->exidx_size = shdr[i].sh_size;
829 * Locate the section headers metadata in a preloaded module, then use it to
830 * locate the exception/unwind table in the module. The size of the metadata
831 * block is stored in a uint32 word immediately before the data itself, and a
832 * comment in preload_search_info() says it is safe to rely on that.
835 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr)
841 modinfo = (uint32_t *)preload_search_info(modptr,
842 MODINFO_METADATA | MODINFOMD_SHDR);
843 if (modinfo != NULL) {
844 shdr = (Elf_Shdr *)modinfo;
845 nhdr = modinfo[-1] / sizeof(Elf_Shdr);
846 link_elf_locate_exidx(lf, shdr, nhdr);
853 link_elf_link_preload(linker_class_t cls, const char *filename,
854 linker_file_t *result)
856 Elf_Addr *ctors_addrp;
857 Elf_Size *ctors_sizep;
858 caddr_t modptr, baseptr, sizeptr, dynptr;
865 /* Look to see if we have the file preloaded */
866 modptr = preload_search_by_name(filename);
870 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
871 baseptr = preload_search_info(modptr, MODINFO_ADDR);
872 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
873 dynptr = preload_search_info(modptr,
874 MODINFO_METADATA | MODINFOMD_DYNAMIC);
876 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
877 strcmp(type, "elf module") != 0))
879 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
882 lf = linker_make_file(filename, &link_elf_class);
886 ef = (elf_file_t) lf;
889 ef->address = *(caddr_t *)baseptr;
890 #ifdef SPARSE_MAPPING
893 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
894 ef->dynamic = (Elf_Dyn *)dp;
895 lf->address = ef->address;
896 lf->size = *(size_t *)sizeptr;
898 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
899 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
900 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
901 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
902 if (ctors_addrp != NULL && ctors_sizep != NULL) {
903 lf->ctors_addr = ef->address + *ctors_addrp;
904 lf->ctors_size = *ctors_sizep;
908 link_elf_locate_exidx_preload(lf, modptr);
911 error = parse_dynamic(ef);
913 error = parse_dpcpu(ef);
916 error = parse_vnet(ef);
919 error = preload_protect(ef, VM_PROT_ALL);
921 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
924 link_elf_reloc_local(lf);
930 link_elf_link_preload_finish(linker_file_t lf)
935 ef = (elf_file_t) lf;
936 error = relocate_file(ef);
938 error = preload_protect(ef, VM_PROT_NONE);
941 (void)link_elf_preload_parse_symbols(ef);
943 return (link_elf_link_common_finish(lf));
947 link_elf_load_file(linker_class_t cls, const char* filename,
948 linker_file_t* result)
951 struct thread* td = curthread; /* XXX */
953 caddr_t firstpage, segbase;
957 Elf_Phdr *segs[MAXSEGS];
963 Elf_Addr base_vlimit;
981 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
983 error = vn_open(&nd, &flags, 0, NULL);
986 NDFREE(&nd, NDF_ONLY_PNBUF);
987 if (nd.ni_vp->v_type != VREG) {
993 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
1001 * Read the elf header from the file.
1003 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
1004 hdr = (Elf_Ehdr *)firstpage;
1005 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
1006 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1008 nbytes = PAGE_SIZE - resid;
1012 if (!IS_ELF(*hdr)) {
1017 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
1018 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
1019 link_elf_error(filename, "Unsupported file layout");
1023 if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
1024 hdr->e_version != EV_CURRENT) {
1025 link_elf_error(filename, "Unsupported file version");
1029 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
1033 if (hdr->e_machine != ELF_TARG_MACH) {
1034 link_elf_error(filename, "Unsupported machine");
1040 * We rely on the program header being in the first page.
1041 * This is not strictly required by the ABI specification, but
1042 * it seems to always true in practice. And, it simplifies
1043 * things considerably.
1045 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
1046 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
1047 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
1048 link_elf_error(filename, "Unreadable program headers");
1051 * Scan the program header entries, and save key information.
1053 * We rely on there being exactly two load segments, text and data,
1056 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
1057 phlimit = phdr + hdr->e_phnum;
1060 while (phdr < phlimit) {
1061 switch (phdr->p_type) {
1063 if (nsegs == MAXSEGS) {
1064 link_elf_error(filename, "Too many sections");
1069 * XXX: We just trust they come in right order ??
1086 if (phdyn == NULL) {
1087 link_elf_error(filename, "Object is not dynamically-linked");
1092 link_elf_error(filename, "No sections");
1098 * Allocate the entire address space of the object, to stake
1099 * out our contiguous region, and to establish the base
1100 * address for relocation.
1102 base_vaddr = trunc_page(segs[0]->p_vaddr);
1103 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
1104 segs[nsegs - 1]->p_memsz);
1105 mapsize = base_vlimit - base_vaddr;
1107 lf = linker_make_file(filename, &link_elf_class);
1113 ef = (elf_file_t) lf;
1114 #ifdef SPARSE_MAPPING
1115 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, mapsize, VM_PROT_ALL,
1116 0, thread0.td_ucred);
1117 if (ef->object == NULL) {
1122 mapbase = (caddr_t)KERNBASE;
1124 mapbase = (caddr_t)vm_map_min(kernel_map);
1127 * Mapping protections are downgraded after relocation processing.
1129 error = vm_map_find(kernel_map, ef->object, 0,
1130 (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE,
1131 VM_PROT_ALL, VM_PROT_ALL, 0);
1133 vm_object_deallocate(ef->object);
1138 mapbase = malloc_exec(mapsize, M_LINKER, M_WAITOK);
1140 ef->address = mapbase;
1143 * Read the text and data sections and zero the bss.
1145 for (i = 0; i < nsegs; i++) {
1146 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1148 #ifdef SPARSE_MAPPING
1150 * Consecutive segments may have different mapping permissions,
1151 * so be strict and verify that their mappings do not overlap.
1153 if (((vm_offset_t)segbase & PAGE_MASK) != 0) {
1158 error = vm_map_wire(kernel_map,
1159 (vm_offset_t)segbase,
1160 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1161 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
1162 if (error != KERN_SUCCESS) {
1168 error = vn_rdwr(UIO_READ, nd.ni_vp,
1169 segbase, segs[i]->p_filesz, segs[i]->p_offset,
1170 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1174 bzero(segbase + segs[i]->p_filesz,
1175 segs[i]->p_memsz - segs[i]->p_filesz);
1179 /* Update profiling information with the new text segment. */
1181 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
1186 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
1188 lf->address = ef->address;
1191 error = parse_dynamic(ef);
1194 error = parse_dpcpu(ef);
1198 error = parse_vnet(ef);
1202 link_elf_reloc_local(lf);
1204 VOP_UNLOCK(nd.ni_vp);
1205 error = linker_load_dependencies(lf);
1206 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1209 error = relocate_file(ef);
1213 #ifdef SPARSE_MAPPING
1215 * Downgrade permissions on text segment mappings now that relocation
1216 * processing is complete. Restrict permissions on read-only segments.
1218 for (i = 0; i < nsegs; i++) {
1221 if (segs[i]->p_type != PT_LOAD)
1224 prot = VM_PROT_READ;
1225 if ((segs[i]->p_flags & PF_W) != 0)
1226 prot |= VM_PROT_WRITE;
1227 if ((segs[i]->p_flags & PF_X) != 0)
1228 prot |= VM_PROT_EXECUTE;
1229 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1230 error = vm_map_protect(kernel_map,
1231 (vm_offset_t)segbase,
1232 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1233 prot, 0, VM_MAP_PROTECT_SET_PROT);
1234 if (error != KERN_SUCCESS) {
1242 * Try and load the symbol table if it's present. (you can
1245 nbytes = hdr->e_shnum * hdr->e_shentsize;
1246 if (nbytes == 0 || hdr->e_shoff == 0)
1248 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1249 error = vn_rdwr(UIO_READ, nd.ni_vp,
1250 (caddr_t)shdr, nbytes, hdr->e_shoff,
1251 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1256 /* Read section string table */
1257 shstrindex = hdr->e_shstrndx;
1258 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1259 shdr[shstrindex].sh_size != 0) {
1260 nbytes = shdr[shstrindex].sh_size;
1261 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1262 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1263 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1264 td->td_ucred, NOCRED, &resid, td);
1271 for (i = 0; i < hdr->e_shnum; i++) {
1272 if (shdr[i].sh_type == SHT_SYMTAB) {
1274 symstrindex = shdr[i].sh_link;
1275 } else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1276 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1277 /* Record relocated address and size of .ctors. */
1278 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1279 lf->ctors_size = shdr[i].sh_size;
1282 if (symtabindex < 0 || symstrindex < 0)
1285 symcnt = shdr[symtabindex].sh_size;
1286 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1287 strcnt = shdr[symstrindex].sh_size;
1288 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1290 error = vn_rdwr(UIO_READ, nd.ni_vp,
1291 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1292 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1296 error = vn_rdwr(UIO_READ, nd.ni_vp,
1297 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1298 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1303 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1304 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1305 ef->ddbstrcnt = strcnt;
1306 ef->ddbstrtab = ef->strbase;
1311 link_elf_locate_exidx(lf, shdr, hdr->e_shnum);
1314 error = link_elf_link_common_finish(lf);
1321 VOP_UNLOCK(nd.ni_vp);
1322 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1323 if (error != 0 && lf != NULL)
1324 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1325 free(shdr, M_LINKER);
1326 free(firstpage, M_LINKER);
1327 free(shstrs, M_LINKER);
1333 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1337 KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class,
1338 ("elf_relocaddr: unexpected linker file %p", lf));
1340 ef = (elf_file_t)lf;
1341 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1342 return ((x - ef->pcpu_start) + ef->pcpu_base);
1344 if (x >= ef->vnet_start && x < ef->vnet_stop)
1345 return ((x - ef->vnet_start) + ef->vnet_base);
1351 link_elf_unload_file(linker_file_t file)
1353 elf_file_t ef = (elf_file_t) file;
1355 if (ef->pcpu_base != 0) {
1356 dpcpu_free((void *)ef->pcpu_base,
1357 ef->pcpu_stop - ef->pcpu_start);
1358 elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1361 if (ef->vnet_base != 0) {
1362 vnet_data_free((void *)ef->vnet_base,
1363 ef->vnet_stop - ef->vnet_start);
1364 elf_set_delete(&set_vnet_list, ef->vnet_start);
1368 if (ef->gdb.l_ld != NULL) {
1369 GDB_STATE(RT_DELETE);
1370 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1371 link_elf_delete_gdb(&ef->gdb);
1372 GDB_STATE(RT_CONSISTENT);
1376 /* Notify MD code that a module is being unloaded. */
1377 elf_cpu_unload_file(file);
1379 if (ef->preloaded) {
1380 link_elf_unload_preload(file);
1384 #ifdef SPARSE_MAPPING
1385 if (ef->object != NULL) {
1386 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1387 (vm_offset_t) ef->address
1388 + (ef->object->size << PAGE_SHIFT));
1391 free(ef->address, M_LINKER);
1393 free(ef->symbase, M_LINKER);
1394 free(ef->strbase, M_LINKER);
1395 free(ef->ctftab, M_LINKER);
1396 free(ef->ctfoff, M_LINKER);
1397 free(ef->typoff, M_LINKER);
1401 link_elf_unload_preload(linker_file_t file)
1404 if (file->pathname != NULL)
1405 preload_delete_name(file->pathname);
1409 symbol_name(elf_file_t ef, Elf_Size r_info)
1413 if (ELF_R_SYM(r_info)) {
1414 ref = ef->symtab + ELF_R_SYM(r_info);
1415 return (ef->strtab + ref->st_name);
1421 symbol_type(elf_file_t ef, Elf_Size r_info)
1425 if (ELF_R_SYM(r_info)) {
1426 ref = ef->symtab + ELF_R_SYM(r_info);
1427 return (ELF_ST_TYPE(ref->st_info));
1429 return (STT_NOTYPE);
1433 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc,
1437 const Elf_Rela *rela;
1438 const char *symname;
1440 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \
1441 for ((iter) = (tbl); (iter) != NULL && \
1442 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \
1443 if ((symbol_type(ef, (iter)->r_info) == \
1445 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \
1447 if (reloc(&ef->lf, (Elf_Addr)ef->address, \
1448 (iter), (type), lookup)) { \
1449 symname = symbol_name(ef, (iter)->r_info); \
1450 printf("link_elf: symbol %s undefined\n", \
1457 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL);
1458 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA);
1459 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL);
1460 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA);
1468 relocate_file(elf_file_t ef)
1472 error = relocate_file1(ef, elf_lookup, elf_reloc, false);
1474 error = relocate_file1(ef, elf_lookup, elf_reloc, true);
1479 * Hash function for symbol table lookup. Don't even think about changing
1480 * this. It is specified by the System V ABI.
1482 static unsigned long
1483 elf_hash(const char *name)
1485 const unsigned char *p = (const unsigned char *) name;
1486 unsigned long h = 0;
1489 while (*p != '\0') {
1490 h = (h << 4) + *p++;
1491 if ((g = h & 0xf0000000) != 0)
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 return (link_elf_lookup_symbol1(lf, name, sym, false));
1559 link_elf_lookup_debug_symbol(linker_file_t lf, const char *name,
1560 c_linker_sym_t *sym)
1562 elf_file_t ef = (elf_file_t)lf;
1563 const Elf_Sym* symp;
1567 if (link_elf_lookup_symbol1(lf, name, sym, true) == 0)
1570 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1571 strp = ef->ddbstrtab + symp->st_name;
1572 if (strcmp(name, strp) == 0) {
1573 if (symp->st_shndx != SHN_UNDEF ||
1574 (symp->st_value != 0 &&
1575 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1576 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1577 *sym = (c_linker_sym_t) symp;
1588 link_elf_symbol_values1(linker_file_t lf, c_linker_sym_t sym,
1589 linker_symval_t *symval, bool see_local)
1595 ef = (elf_file_t)lf;
1596 es = (const Elf_Sym *)sym;
1597 if (es >= ef->symtab && es < ef->symtab + ef->nchains) {
1598 if (!see_local && ELF_ST_BIND(es->st_info) == STB_LOCAL)
1600 symval->name = ef->strtab + es->st_name;
1601 val = (caddr_t)ef->address + es->st_value;
1602 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1603 val = ((caddr_t (*)(void))val)();
1604 symval->value = val;
1605 symval->size = es->st_size;
1612 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1613 linker_symval_t *symval)
1615 return (link_elf_symbol_values1(lf, sym, symval, false));
1619 link_elf_debug_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1620 linker_symval_t *symval)
1622 elf_file_t ef = (elf_file_t)lf;
1623 const Elf_Sym *es = (const Elf_Sym *)sym;
1626 if (link_elf_symbol_values1(lf, sym, symval, true) == 0)
1628 if (ef->symtab == ef->ddbsymtab)
1631 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1632 symval->name = ef->ddbstrtab + es->st_name;
1633 val = (caddr_t)ef->address + es->st_value;
1634 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1635 val = ((caddr_t (*)(void))val)();
1636 symval->value = val;
1637 symval->size = es->st_size;
1644 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1645 c_linker_sym_t *sym, long *diffp)
1647 elf_file_t ef = (elf_file_t)lf;
1648 u_long off = (uintptr_t)(void *)value;
1652 const Elf_Sym *best = NULL;
1655 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1656 if (es->st_name == 0)
1658 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1659 if (off >= st_value) {
1660 if (off - st_value < diff) {
1661 diff = off - st_value;
1665 } else if (off - st_value == diff) {
1674 *sym = (c_linker_sym_t) best;
1680 * Look up a linker set on an ELF system.
1683 link_elf_lookup_set(linker_file_t lf, const char *name,
1684 void ***startp, void ***stopp, int *countp)
1687 linker_symval_t symval;
1689 void **start, **stop;
1690 int len, error = 0, count;
1692 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1693 setsym = malloc(len, M_LINKER, M_WAITOK);
1695 /* get address of first entry */
1696 snprintf(setsym, len, "%s%s", "__start_set_", name);
1697 error = link_elf_lookup_symbol(lf, setsym, &sym);
1700 link_elf_symbol_values(lf, sym, &symval);
1701 if (symval.value == 0) {
1705 start = (void **)symval.value;
1707 /* get address of last entry */
1708 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1709 error = link_elf_lookup_symbol(lf, setsym, &sym);
1712 link_elf_symbol_values(lf, sym, &symval);
1713 if (symval.value == 0) {
1717 stop = (void **)symval.value;
1719 /* and the number of entries */
1720 count = stop - start;
1731 free(setsym, M_LINKER);
1736 link_elf_each_function_name(linker_file_t file,
1737 int (*callback)(const char *, void *), void *opaque)
1739 elf_file_t ef = (elf_file_t)file;
1740 const Elf_Sym *symp;
1743 /* Exhaustive search */
1744 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1745 if (symp->st_value != 0 &&
1746 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1747 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1748 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1757 link_elf_each_function_nameval(linker_file_t file,
1758 linker_function_nameval_callback_t callback, void *opaque)
1760 linker_symval_t symval;
1761 elf_file_t ef = (elf_file_t)file;
1762 const Elf_Sym *symp;
1765 /* Exhaustive search */
1766 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1767 if (symp->st_value != 0 &&
1768 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1769 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1770 error = link_elf_debug_symbol_values(file,
1771 (c_linker_sym_t) symp, &symval);
1773 error = callback(file, i, &symval, opaque);
1782 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1784 elf_file_t ef = (elf_file_t)lf;
1786 if (symidx >= ef->nchains)
1788 return (ef->symtab + symidx);
1792 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1794 elf_file_t ef = (elf_file_t)lf;
1797 if (symidx >= ef->nchains)
1799 sym = ef->symtab + symidx;
1800 return (ef->strtab + sym->st_name);
1804 * Symbol lookup function that can be used when the symbol index is known (ie
1805 * in relocations). It uses the symbol index instead of doing a fully fledged
1806 * hash table based lookup when such is valid. For example for local symbols.
1807 * This is not only more efficient, it's also more correct. It's not always
1808 * the case that the symbol can be found through the hash table.
1811 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1813 elf_file_t ef = (elf_file_t)lf;
1816 Elf_Addr addr, start, base;
1818 /* Don't even try to lookup the symbol if the index is bogus. */
1819 if (symidx >= ef->nchains) {
1824 sym = ef->symtab + symidx;
1827 * Don't do a full lookup when the symbol is local. It may even
1828 * fail because it may not be found through the hash table.
1830 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1831 /* Force lookup failure when we have an insanity. */
1832 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1836 *res = ((Elf_Addr)ef->address + sym->st_value);
1841 * XXX we can avoid doing a hash table based lookup for global
1842 * symbols as well. This however is not always valid, so we'll
1843 * just do it the hard way for now. Performance tweaks can
1847 symbol = ef->strtab + sym->st_name;
1849 /* Force a lookup failure if the symbol name is bogus. */
1855 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1856 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1861 if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1862 addr = addr - start + base;
1864 else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1865 addr = addr - start + base;
1872 link_elf_reloc_local(linker_file_t lf)
1874 const Elf_Rel *rellim;
1876 const Elf_Rela *relalim;
1877 const Elf_Rela *rela;
1878 elf_file_t ef = (elf_file_t)lf;
1880 /* Perform relocations without addend if there are any: */
1881 if ((rel = ef->rel) != NULL) {
1882 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1883 while (rel < rellim) {
1884 elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1885 ELF_RELOC_REL, elf_lookup);
1890 /* Perform relocations with addend if there are any: */
1891 if ((rela = ef->rela) != NULL) {
1892 relalim = (const Elf_Rela *)
1893 ((const char *)ef->rela + ef->relasize);
1894 while (rela < relalim) {
1895 elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1896 ELF_RELOC_RELA, elf_lookup);
1903 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1905 elf_file_t ef = (elf_file_t)lf;
1907 *symtab = ef->ddbsymtab;
1909 if (*symtab == NULL)
1912 return (ef->ddbsymcnt);
1916 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1918 elf_file_t ef = (elf_file_t)lf;
1920 *strtab = ef->ddbstrtab;
1922 if (*strtab == NULL)
1925 return (ef->ddbstrcnt);
1928 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) || defined(__powerpc__)
1930 * Use this lookup routine when performing relocations early during boot.
1931 * The generic lookup routine depends on kobj, which is not initialized
1935 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused,
1939 const Elf_Sym *symp;
1942 ef = (elf_file_t)lf;
1943 symp = ef->symtab + symidx;
1944 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) {
1945 val = (caddr_t)ef->address + symp->st_value;
1946 *res = ((Elf_Addr (*)(void))val)();
1953 link_elf_ireloc(caddr_t kmdp)
1955 struct elf_file eff;
1960 bzero_early(ef, sizeof(*ef));
1963 ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
1965 #ifdef RELOCATABLE_KERNEL
1966 ef->address = (caddr_t) (__startkernel - KERNBASE);
1972 link_elf_preload_parse_symbols(ef);
1973 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true);
1976 #if defined(__aarch64__) || defined(__amd64__)
1978 link_elf_late_ireloc(void)
1982 KASSERT(linker_kernel_file != NULL,
1983 ("link_elf_late_ireloc: No kernel linker file found"));
1984 ef = (elf_file_t)linker_kernel_file;
1986 relocate_file1(ef, elf_lookup_ifunc, elf_reloc_late, true);