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>
35 #include <sys/kernel.h>
37 #include <sys/malloc.h>
41 #include <sys/mutex.h>
42 #include <sys/mount.h>
45 #include <sys/namei.h>
46 #include <sys/fcntl.h>
47 #include <sys/vnode.h>
48 #include <sys/linker.h>
49 #include <sys/sysctl.h>
50 #include <sys/tslog.h>
52 #include <machine/elf.h>
56 #include <security/mac/mac_framework.h>
59 #include <vm/vm_param.h>
61 #include <vm/vm_object.h>
62 #include <vm/vm_kern.h>
63 #include <vm/vm_extern.h>
66 #include <vm/vm_map.h>
68 #include <sys/link_elf.h>
70 #include "linker_if.h"
74 typedef struct elf_file {
75 struct linker_file lf; /* Common fields */
76 int preloaded; /* Was file pre-loaded */
77 caddr_t address; /* Relocation address */
79 vm_object_t object; /* VM object to hold file pages */
81 Elf_Dyn *dynamic; /* Symbol table etc. */
82 Elf_Hashelt nbuckets; /* DT_HASH info */
84 const Elf_Hashelt *buckets;
85 const Elf_Hashelt *chains;
87 caddr_t strtab; /* DT_STRTAB */
88 int strsz; /* DT_STRSZ */
89 const Elf_Sym *symtab; /* DT_SYMTAB */
90 Elf_Addr *got; /* DT_PLTGOT */
91 const Elf_Rel *pltrel; /* DT_JMPREL */
92 int pltrelsize; /* DT_PLTRELSZ */
93 const Elf_Rela *pltrela; /* DT_JMPREL */
94 int pltrelasize; /* DT_PLTRELSZ */
95 const Elf_Rel *rel; /* DT_REL */
96 int relsize; /* DT_RELSZ */
97 const Elf_Rela *rela; /* DT_RELA */
98 int relasize; /* DT_RELASZ */
100 const Elf_Sym *ddbsymtab; /* The symbol table we are using */
101 long ddbsymcnt; /* Number of symbols */
102 caddr_t ddbstrtab; /* String table */
103 long ddbstrcnt; /* number of bytes in string table */
104 caddr_t symbase; /* malloc'ed symbold base */
105 caddr_t strbase; /* malloc'ed string base */
106 caddr_t ctftab; /* CTF table */
107 long ctfcnt; /* number of bytes in CTF table */
108 caddr_t ctfoff; /* CTF offset table */
109 caddr_t typoff; /* Type offset table */
110 long typlen; /* Number of type entries. */
111 Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */
112 Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */
113 Elf_Addr pcpu_base; /* Relocated pcpu set address. */
115 Elf_Addr vnet_start; /* Pre-relocation vnet set start. */
116 Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */
117 Elf_Addr vnet_base; /* Relocated vnet set address. */
120 struct link_map gdb; /* hooks for gdb */
128 TAILQ_ENTRY(elf_set) es_link;
131 TAILQ_HEAD(elf_set_head, elf_set);
133 #include <kern/kern_ctf.c>
135 static int link_elf_link_common_finish(linker_file_t);
136 static int link_elf_link_preload(linker_class_t cls,
137 const char *, linker_file_t *);
138 static int link_elf_link_preload_finish(linker_file_t);
139 static int link_elf_load_file(linker_class_t, const char *,
141 static int link_elf_lookup_symbol(linker_file_t, const char *,
143 static int link_elf_lookup_debug_symbol(linker_file_t, const char *,
145 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
147 static int link_elf_debug_symbol_values(linker_file_t, c_linker_sym_t,
149 static int link_elf_search_symbol(linker_file_t, caddr_t,
150 c_linker_sym_t *, long *);
152 static void link_elf_unload_file(linker_file_t);
153 static void link_elf_unload_preload(linker_file_t);
154 static int link_elf_lookup_set(linker_file_t, const char *,
155 void ***, void ***, int *);
156 static int link_elf_each_function_name(linker_file_t,
157 int (*)(const char *, void *), void *);
158 static int link_elf_each_function_nameval(linker_file_t,
159 linker_function_nameval_callback_t, void *);
160 static void link_elf_reloc_local(linker_file_t);
161 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
162 static long link_elf_strtab_get(linker_file_t, caddr_t *);
164 static void link_elf_propagate_vnets(linker_file_t);
166 static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
168 static kobj_method_t link_elf_methods[] = {
169 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
170 KOBJMETHOD(linker_lookup_debug_symbol, link_elf_lookup_debug_symbol),
171 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
172 KOBJMETHOD(linker_debug_symbol_values, link_elf_debug_symbol_values),
173 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
174 KOBJMETHOD(linker_unload, link_elf_unload_file),
175 KOBJMETHOD(linker_load_file, link_elf_load_file),
176 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
177 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
178 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
179 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
180 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
181 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
182 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
183 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
185 KOBJMETHOD(linker_propagate_vnets, link_elf_propagate_vnets),
190 static struct linker_class link_elf_class = {
191 #if ELF_TARG_CLASS == ELFCLASS32
196 link_elf_methods, sizeof(struct elf_file)
199 static bool link_elf_leak_locals = true;
200 SYSCTL_BOOL(_debug, OID_AUTO, link_elf_leak_locals,
201 CTLFLAG_RWTUN, &link_elf_leak_locals, 0,
202 "Allow local symbols to participate in global module symbol resolution");
204 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase,
205 const void *data, int type, elf_lookup_fn lookup);
207 static int parse_dynamic(elf_file_t);
208 static int relocate_file(elf_file_t);
209 static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup,
210 elf_reloc_fn reloc, bool ifuncs);
211 static int link_elf_preload_parse_symbols(elf_file_t);
213 static struct elf_set_head set_pcpu_list;
215 static struct elf_set_head set_vnet_list;
219 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
221 struct elf_set *set, *iter;
223 set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
224 set->es_start = start;
228 TAILQ_FOREACH(iter, list, es_link) {
229 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
230 (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
231 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
232 (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
233 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
235 if (iter->es_start > set->es_start) {
236 TAILQ_INSERT_BEFORE(iter, set, es_link);
242 TAILQ_INSERT_TAIL(list, set, es_link);
246 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
250 TAILQ_FOREACH(set, list, es_link) {
251 if (addr < set->es_start)
253 if (addr < set->es_stop) {
254 *start = set->es_start;
255 *base = set->es_base;
264 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
268 TAILQ_FOREACH(set, list, es_link) {
269 if (start < set->es_start)
271 if (start == set->es_start) {
272 TAILQ_REMOVE(list, set, es_link);
277 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
282 static void r_debug_state(struct r_debug *, struct link_map *);
285 * A list of loaded modules for GDB to use for loading symbols.
287 struct r_debug r_debug;
289 #define GDB_STATE(s) do { \
290 r_debug.r_state = s; r_debug_state(NULL, NULL); \
294 * Function for the debugger to set a breakpoint on to gain control.
297 r_debug_state(struct r_debug *dummy_one __unused,
298 struct link_map *dummy_two __unused)
303 link_elf_add_gdb(struct link_map *l)
305 struct link_map *prev;
309 if (r_debug.r_map == NULL) {
314 /* Append to list. */
315 for (prev = r_debug.r_map;
316 prev->l_next != NULL;
325 link_elf_delete_gdb(struct link_map *l)
327 if (l->l_prev == NULL) {
329 if ((r_debug.r_map = l->l_next) != NULL)
330 l->l_next->l_prev = NULL;
332 /* Remove any but first. */
333 if ((l->l_prev->l_next = l->l_next) != NULL)
334 l->l_next->l_prev = l->l_prev;
340 * The kernel symbol table starts here.
342 extern struct _dynamic _DYNAMIC;
345 link_elf_error(const char *filename, const char *s)
347 if (filename == NULL)
348 printf("kldload: %s\n", s);
350 printf("kldload: %s: %s\n", filename, s);
354 link_elf_invoke_ctors(caddr_t addr, size_t size)
359 if (addr == NULL || size == 0)
361 cnt = size / sizeof(*ctor);
363 for (i = 0; i < cnt; i++) {
370 * Actions performed after linking/loading both the preloaded kernel and any
371 * modules; whether preloaded or dynamicly loaded.
374 link_elf_link_common_finish(linker_file_t lf)
377 elf_file_t ef = (elf_file_t)lf;
382 /* Notify MD code that a module is being loaded. */
383 error = elf_cpu_load_file(lf);
389 ef->gdb.l_addr = lf->address;
390 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
391 strcpy(newfilename, lf->filename);
392 ef->gdb.l_name = newfilename;
393 ef->gdb.l_ld = ef->dynamic;
394 link_elf_add_gdb(&ef->gdb);
395 GDB_STATE(RT_CONSISTENT);
399 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
403 #ifdef RELOCATABLE_KERNEL
405 * __startkernel and __endkernel are symbols set up as relocation canaries.
407 * They are defined in locore to reference linker script symbols at the
408 * beginning and end of the LOAD area. This has the desired side effect of
409 * giving us variables that have relative relocations pointing at them, so
410 * relocation of the kernel object will cause the variables to be updated
411 * automatically by the runtime linker when we initialize.
413 * There are two main reasons to relocate the kernel:
414 * 1) If the loader needed to load the kernel at an alternate load address.
415 * 2) If the kernel is switching address spaces on machines like POWER9
416 * under Radix where the high bits of the effective address are used to
417 * differentiate between hypervisor, host, guest, and problem state.
419 extern vm_offset_t __startkernel, __endkernel;
422 static unsigned long kern_relbase = KERNBASE;
424 SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD,
425 SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address");
426 SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD,
427 &kern_relbase, 0, "Kernel relocated base address");
430 link_elf_init(void* arg)
433 Elf_Addr *ctors_addrp;
434 Elf_Size *ctors_sizep;
435 caddr_t modptr, baseptr, sizeptr;
439 linker_add_class(&link_elf_class);
441 dp = (Elf_Dyn *)&_DYNAMIC;
443 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
445 modptr = preload_search_by_type("elf kernel");
446 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
449 linker_kernel_file = linker_make_file(modname, &link_elf_class);
450 if (linker_kernel_file == NULL)
451 panic("%s: Can't create linker structures for kernel",
454 ef = (elf_file_t) linker_kernel_file;
456 #ifdef RELOCATABLE_KERNEL
457 /* Compute relative displacement */
458 ef->address = (caddr_t) (__startkernel - KERNBASE);
462 #ifdef SPARSE_MAPPING
469 #ifdef RELOCATABLE_KERNEL
470 linker_kernel_file->address = (caddr_t)__startkernel;
471 linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
472 kern_relbase = (unsigned long)__startkernel;
474 linker_kernel_file->address += KERNBASE;
475 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
478 if (modptr != NULL) {
480 baseptr = preload_search_info(modptr, MODINFO_ADDR);
482 linker_kernel_file->address = *(caddr_t *)baseptr;
483 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
485 linker_kernel_file->size = *(size_t *)sizeptr;
486 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
487 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
488 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
489 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
490 if (ctors_addrp != NULL && ctors_sizep != NULL) {
491 linker_kernel_file->ctors_addr = ef->address +
493 linker_kernel_file->ctors_size = *ctors_sizep;
496 (void)link_elf_preload_parse_symbols(ef);
499 r_debug.r_map = NULL;
500 r_debug.r_brk = r_debug_state;
501 r_debug.r_state = RT_CONSISTENT;
504 (void)link_elf_link_common_finish(linker_kernel_file);
505 linker_kernel_file->flags |= LINKER_FILE_LINKED;
506 TAILQ_INIT(&set_pcpu_list);
508 TAILQ_INIT(&set_vnet_list);
509 vnet_save_init((void *)VNET_START, VNET_STOP - VNET_START);
513 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL);
516 link_elf_preload_parse_symbols(elf_file_t ef)
519 caddr_t ssym, esym, base;
525 if (ef->modptr == NULL)
527 pointer = preload_search_info(ef->modptr,
528 MODINFO_METADATA | MODINFOMD_SSYM);
531 ssym = *(caddr_t *)pointer;
532 pointer = preload_search_info(ef->modptr,
533 MODINFO_METADATA | MODINFOMD_ESYM);
536 esym = *(caddr_t *)pointer;
540 symcnt = *(long *)base;
541 base += sizeof(long);
542 symtab = (Elf_Sym *)base;
543 base += roundup(symcnt, sizeof(long));
545 if (base > esym || base < ssym) {
546 printf("Symbols are corrupt!\n");
550 strcnt = *(long *)base;
551 base += sizeof(long);
553 base += roundup(strcnt, sizeof(long));
555 if (base > esym || base < ssym) {
556 printf("Symbols are corrupt!\n");
560 ef->ddbsymtab = symtab;
561 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
562 ef->ddbstrtab = strtab;
563 ef->ddbstrcnt = strcnt;
569 parse_dynamic(elf_file_t ef)
572 int plttype = DT_REL;
574 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
578 /* From src/libexec/rtld-elf/rtld.c */
579 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
580 (ef->address + dp->d_un.d_ptr);
581 ef->nbuckets = hashtab[0];
582 ef->nchains = hashtab[1];
583 ef->buckets = hashtab + 2;
584 ef->chains = ef->buckets + ef->nbuckets;
588 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
591 ef->strsz = dp->d_un.d_val;
594 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
597 if (dp->d_un.d_val != sizeof(Elf_Sym))
601 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
604 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
607 ef->relsize = dp->d_un.d_val;
610 if (dp->d_un.d_val != sizeof(Elf_Rel))
614 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
617 ef->pltrelsize = dp->d_un.d_val;
620 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
623 ef->relasize = dp->d_un.d_val;
626 if (dp->d_un.d_val != sizeof(Elf_Rela))
630 plttype = dp->d_un.d_val;
631 if (plttype != DT_REL && plttype != DT_RELA)
636 dp->d_un.d_ptr = (Elf_Addr)&r_debug;
642 if (plttype == DT_RELA) {
643 ef->pltrela = (const Elf_Rela *)ef->pltrel;
645 ef->pltrelasize = ef->pltrelsize;
649 ef->ddbsymtab = ef->symtab;
650 ef->ddbsymcnt = ef->nchains;
651 ef->ddbstrtab = ef->strtab;
652 ef->ddbstrcnt = ef->strsz;
654 return elf_cpu_parse_dynamic(ef->address, ef->dynamic);
657 #define LS_PADDING 0x90909090
659 parse_dpcpu(elf_file_t ef)
662 #if defined(__i386__)
668 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
669 (void ***)&ef->pcpu_stop, NULL);
670 /* Error just means there is no pcpu set to relocate. */
673 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start;
677 #if defined(__i386__)
678 /* In case we do find __start/stop_set_ symbols double-check. */
680 uprintf("Kernel module '%s' must be recompiled with "
681 "linker script\n", ef->lf.pathname);
685 /* Padding from linker-script correct? */
686 pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad));
687 if (pad != LS_PADDING) {
688 uprintf("Kernel module '%s' must be recompiled with "
689 "linker script, invalid padding %#04x (%#04x)\n",
690 ef->lf.pathname, pad, LS_PADDING);
693 /* If we only have valid padding, nothing to do. */
698 * Allocate space in the primary pcpu area. Copy in our
699 * initialization from the data section and then initialize
700 * all per-cpu storage from that.
702 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size);
703 if (ef->pcpu_base == 0) {
704 printf("%s: pcpu module space is out of space; "
705 "cannot allocate %d for %s\n",
706 __func__, size, ef->lf.pathname);
709 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size);
710 dpcpu_copy((void *)ef->pcpu_base, size);
711 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
719 parse_vnet(elf_file_t ef)
722 #if defined(__i386__)
729 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
730 (void ***)&ef->vnet_stop, NULL);
731 /* Error just means there is no vnet data set to relocate. */
734 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
738 #if defined(__i386__)
739 /* In case we do find __start/stop_set_ symbols double-check. */
741 uprintf("Kernel module '%s' must be recompiled with "
742 "linker script\n", ef->lf.pathname);
746 /* Padding from linker-script correct? */
747 pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad));
748 if (pad != LS_PADDING) {
749 uprintf("Kernel module '%s' must be recompiled with "
750 "linker script, invalid padding %#04x (%#04x)\n",
751 ef->lf.pathname, pad, LS_PADDING);
754 /* If we only have valid padding, nothing to do. */
759 * Allocate space in the primary vnet area. Copy in our
760 * initialization from the data section and then initialize
761 * all per-vnet storage from that.
763 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size);
764 if (ef->vnet_base == 0) {
765 printf("%s: vnet module space is out of space; "
766 "cannot allocate %d for %s\n",
767 __func__, size, ef->lf.pathname);
770 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size);
771 vnet_save_init((void *)ef->vnet_base, size);
772 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
781 * Apply the specified protection to the loadable segments of a preloaded linker
785 preload_protect(elf_file_t ef, vm_prot_t prot)
787 #if defined(__aarch64__) || defined(__amd64__)
789 Elf_Phdr *phdr, *phlimit;
794 hdr = (Elf_Ehdr *)ef->address;
795 phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff);
796 phlimit = phdr + hdr->e_phnum;
797 for (; phdr < phlimit; phdr++) {
798 if (phdr->p_type != PT_LOAD)
801 nprot = prot | VM_PROT_READ;
802 if ((phdr->p_flags & PF_W) != 0)
803 nprot |= VM_PROT_WRITE;
804 if ((phdr->p_flags & PF_X) != 0)
805 nprot |= VM_PROT_EXECUTE;
806 error = pmap_change_prot((vm_offset_t)ef->address +
807 phdr->p_vaddr, round_page(phdr->p_memsz), nprot);
819 * Locate the ARM exception/unwind table info for DDB and stack(9) use by
820 * searching for the section header that describes it. There may be no unwind
821 * info, for example in a module containing only data.
824 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr)
828 for (i = 0; i < nhdr; i++) {
829 if (shdr[i].sh_type == SHT_ARM_EXIDX) {
830 lf->exidx_addr = shdr[i].sh_addr + lf->address;
831 lf->exidx_size = shdr[i].sh_size;
838 * Locate the section headers metadata in a preloaded module, then use it to
839 * locate the exception/unwind table in the module. The size of the metadata
840 * block is stored in a uint32 word immediately before the data itself, and a
841 * comment in preload_search_info() says it is safe to rely on that.
844 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr)
850 modinfo = (uint32_t *)preload_search_info(modptr,
851 MODINFO_METADATA | MODINFOMD_SHDR);
852 if (modinfo != NULL) {
853 shdr = (Elf_Shdr *)modinfo;
854 nhdr = modinfo[-1] / sizeof(Elf_Shdr);
855 link_elf_locate_exidx(lf, shdr, nhdr);
862 link_elf_link_preload(linker_class_t cls, const char *filename,
863 linker_file_t *result)
865 Elf_Addr *ctors_addrp;
866 Elf_Size *ctors_sizep;
867 caddr_t modptr, baseptr, sizeptr, dynptr;
874 /* Look to see if we have the file preloaded */
875 modptr = preload_search_by_name(filename);
879 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
880 baseptr = preload_search_info(modptr, MODINFO_ADDR);
881 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
882 dynptr = preload_search_info(modptr,
883 MODINFO_METADATA | MODINFOMD_DYNAMIC);
885 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
886 strcmp(type, "elf module") != 0))
888 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
891 lf = linker_make_file(filename, &link_elf_class);
895 ef = (elf_file_t) lf;
898 ef->address = *(caddr_t *)baseptr;
899 #ifdef SPARSE_MAPPING
902 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
903 ef->dynamic = (Elf_Dyn *)dp;
904 lf->address = ef->address;
905 lf->size = *(size_t *)sizeptr;
907 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
908 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
909 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
910 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
911 if (ctors_addrp != NULL && ctors_sizep != NULL) {
912 lf->ctors_addr = ef->address + *ctors_addrp;
913 lf->ctors_size = *ctors_sizep;
917 link_elf_locate_exidx_preload(lf, modptr);
920 error = parse_dynamic(ef);
922 error = parse_dpcpu(ef);
925 error = parse_vnet(ef);
928 error = preload_protect(ef, VM_PROT_ALL);
930 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
933 link_elf_reloc_local(lf);
939 link_elf_link_preload_finish(linker_file_t lf)
944 ef = (elf_file_t) lf;
945 error = relocate_file(ef);
947 error = preload_protect(ef, VM_PROT_NONE);
950 (void)link_elf_preload_parse_symbols(ef);
952 return (link_elf_link_common_finish(lf));
956 link_elf_load_file(linker_class_t cls, const char* filename,
957 linker_file_t* result)
960 struct thread* td = curthread; /* XXX */
962 caddr_t firstpage, segbase;
966 Elf_Phdr *segs[MAXSEGS];
972 Elf_Addr base_vlimit;
990 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename);
992 error = vn_open(&nd, &flags, 0, NULL);
996 if (nd.ni_vp->v_type != VREG) {
1002 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
1010 * Read the elf header from the file.
1012 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
1013 hdr = (Elf_Ehdr *)firstpage;
1014 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
1015 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1017 nbytes = PAGE_SIZE - resid;
1021 if (!IS_ELF(*hdr)) {
1026 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
1027 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
1028 link_elf_error(filename, "Unsupported file layout");
1032 if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
1033 hdr->e_version != EV_CURRENT) {
1034 link_elf_error(filename, "Unsupported file version");
1038 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
1042 if (hdr->e_machine != ELF_TARG_MACH) {
1043 link_elf_error(filename, "Unsupported machine");
1049 * We rely on the program header being in the first page.
1050 * This is not strictly required by the ABI specification, but
1051 * it seems to always true in practice. And, it simplifies
1052 * things considerably.
1054 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
1055 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
1056 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
1057 link_elf_error(filename, "Unreadable program headers");
1060 * Scan the program header entries, and save key information.
1062 * We rely on there being exactly two load segments, text and data,
1065 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
1066 phlimit = phdr + hdr->e_phnum;
1069 while (phdr < phlimit) {
1070 switch (phdr->p_type) {
1072 if (nsegs == MAXSEGS) {
1073 link_elf_error(filename, "Too many sections");
1078 * XXX: We just trust they come in right order ??
1095 if (phdyn == NULL) {
1096 link_elf_error(filename, "Object is not dynamically-linked");
1101 link_elf_error(filename, "No sections");
1107 * Allocate the entire address space of the object, to stake
1108 * out our contiguous region, and to establish the base
1109 * address for relocation.
1111 base_vaddr = trunc_page(segs[0]->p_vaddr);
1112 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
1113 segs[nsegs - 1]->p_memsz);
1114 mapsize = base_vlimit - base_vaddr;
1116 lf = linker_make_file(filename, &link_elf_class);
1122 ef = (elf_file_t) lf;
1123 #ifdef SPARSE_MAPPING
1124 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, mapsize, VM_PROT_ALL,
1125 0, thread0.td_ucred);
1126 if (ef->object == NULL) {
1131 mapbase = (caddr_t)KERNBASE;
1133 mapbase = (caddr_t)vm_map_min(kernel_map);
1136 * Mapping protections are downgraded after relocation processing.
1138 error = vm_map_find(kernel_map, ef->object, 0,
1139 (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE,
1140 VM_PROT_ALL, VM_PROT_ALL, 0);
1142 vm_object_deallocate(ef->object);
1147 mapbase = malloc_exec(mapsize, M_LINKER, M_WAITOK);
1149 ef->address = mapbase;
1152 * Read the text and data sections and zero the bss.
1154 for (i = 0; i < nsegs; i++) {
1155 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1157 #ifdef SPARSE_MAPPING
1159 * Consecutive segments may have different mapping permissions,
1160 * so be strict and verify that their mappings do not overlap.
1162 if (((vm_offset_t)segbase & PAGE_MASK) != 0) {
1167 error = vm_map_wire(kernel_map,
1168 (vm_offset_t)segbase,
1169 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1170 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
1171 if (error != KERN_SUCCESS) {
1177 error = vn_rdwr(UIO_READ, nd.ni_vp,
1178 segbase, segs[i]->p_filesz, segs[i]->p_offset,
1179 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1183 bzero(segbase + segs[i]->p_filesz,
1184 segs[i]->p_memsz - segs[i]->p_filesz);
1187 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
1189 lf->address = ef->address;
1192 error = parse_dynamic(ef);
1195 error = parse_dpcpu(ef);
1199 error = parse_vnet(ef);
1203 link_elf_reloc_local(lf);
1205 VOP_UNLOCK(nd.ni_vp);
1206 error = linker_load_dependencies(lf);
1207 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1210 error = relocate_file(ef);
1214 #ifdef SPARSE_MAPPING
1216 * Downgrade permissions on text segment mappings now that relocation
1217 * processing is complete. Restrict permissions on read-only segments.
1219 for (i = 0; i < nsegs; i++) {
1222 if (segs[i]->p_type != PT_LOAD)
1225 prot = VM_PROT_READ;
1226 if ((segs[i]->p_flags & PF_W) != 0)
1227 prot |= VM_PROT_WRITE;
1228 if ((segs[i]->p_flags & PF_X) != 0)
1229 prot |= VM_PROT_EXECUTE;
1230 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1231 error = vm_map_protect(kernel_map,
1232 (vm_offset_t)segbase,
1233 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1234 prot, 0, VM_MAP_PROTECT_SET_PROT);
1235 if (error != KERN_SUCCESS) {
1243 * Try and load the symbol table if it's present. (you can
1246 nbytes = hdr->e_shnum * hdr->e_shentsize;
1247 if (nbytes == 0 || hdr->e_shoff == 0)
1249 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1250 error = vn_rdwr(UIO_READ, nd.ni_vp,
1251 (caddr_t)shdr, nbytes, hdr->e_shoff,
1252 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1257 /* Read section string table */
1258 shstrindex = hdr->e_shstrndx;
1259 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1260 shdr[shstrindex].sh_size != 0) {
1261 nbytes = shdr[shstrindex].sh_size;
1262 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1263 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1264 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1265 td->td_ucred, NOCRED, &resid, td);
1272 for (i = 0; i < hdr->e_shnum; i++) {
1273 if (shdr[i].sh_type == SHT_SYMTAB) {
1275 symstrindex = shdr[i].sh_link;
1276 } else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1277 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1278 /* Record relocated address and size of .ctors. */
1279 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1280 lf->ctors_size = shdr[i].sh_size;
1283 if (symtabindex < 0 || symstrindex < 0)
1286 symcnt = shdr[symtabindex].sh_size;
1287 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1288 strcnt = shdr[symstrindex].sh_size;
1289 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1291 error = vn_rdwr(UIO_READ, nd.ni_vp,
1292 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1293 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1297 error = vn_rdwr(UIO_READ, nd.ni_vp,
1298 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1299 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1304 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1305 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1306 ef->ddbstrcnt = strcnt;
1307 ef->ddbstrtab = ef->strbase;
1312 link_elf_locate_exidx(lf, shdr, hdr->e_shnum);
1315 error = link_elf_link_common_finish(lf);
1322 VOP_UNLOCK(nd.ni_vp);
1323 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1324 if (error != 0 && lf != NULL)
1325 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1326 free(shdr, M_LINKER);
1327 free(firstpage, M_LINKER);
1328 free(shstrs, M_LINKER);
1334 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1338 KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class,
1339 ("elf_relocaddr: unexpected linker file %p", lf));
1341 ef = (elf_file_t)lf;
1342 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1343 return ((x - ef->pcpu_start) + ef->pcpu_base);
1345 if (x >= ef->vnet_start && x < ef->vnet_stop)
1346 return ((x - ef->vnet_start) + ef->vnet_base);
1352 link_elf_unload_file(linker_file_t file)
1354 elf_file_t ef = (elf_file_t) file;
1356 if (ef->pcpu_base != 0) {
1357 dpcpu_free((void *)ef->pcpu_base,
1358 ef->pcpu_stop - ef->pcpu_start);
1359 elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1362 if (ef->vnet_base != 0) {
1363 vnet_data_free((void *)ef->vnet_base,
1364 ef->vnet_stop - ef->vnet_start);
1365 elf_set_delete(&set_vnet_list, ef->vnet_start);
1369 if (ef->gdb.l_ld != NULL) {
1370 GDB_STATE(RT_DELETE);
1371 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1372 link_elf_delete_gdb(&ef->gdb);
1373 GDB_STATE(RT_CONSISTENT);
1377 /* Notify MD code that a module is being unloaded. */
1378 elf_cpu_unload_file(file);
1380 if (ef->preloaded) {
1381 link_elf_unload_preload(file);
1385 #ifdef SPARSE_MAPPING
1386 if (ef->object != NULL) {
1387 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1388 (vm_offset_t) ef->address
1389 + (ef->object->size << PAGE_SHIFT));
1392 free(ef->address, M_LINKER);
1394 free(ef->symbase, M_LINKER);
1395 free(ef->strbase, M_LINKER);
1396 free(ef->ctftab, M_LINKER);
1397 free(ef->ctfoff, M_LINKER);
1398 free(ef->typoff, M_LINKER);
1402 link_elf_unload_preload(linker_file_t file)
1405 if (file->pathname != NULL)
1406 preload_delete_name(file->pathname);
1410 symbol_name(elf_file_t ef, Elf_Size r_info)
1414 if (ELF_R_SYM(r_info)) {
1415 ref = ef->symtab + ELF_R_SYM(r_info);
1416 return (ef->strtab + ref->st_name);
1422 symbol_type(elf_file_t ef, Elf_Size r_info)
1426 if (ELF_R_SYM(r_info)) {
1427 ref = ef->symtab + ELF_R_SYM(r_info);
1428 return (ELF_ST_TYPE(ref->st_info));
1430 return (STT_NOTYPE);
1434 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc,
1438 const Elf_Rela *rela;
1439 const char *symname;
1442 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \
1443 for ((iter) = (tbl); (iter) != NULL && \
1444 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \
1445 if ((symbol_type(ef, (iter)->r_info) == \
1447 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \
1449 if (reloc(&ef->lf, (Elf_Addr)ef->address, \
1450 (iter), (type), lookup)) { \
1451 symname = symbol_name(ef, (iter)->r_info); \
1452 printf("link_elf: symbol %s undefined\n", \
1459 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL);
1460 TSENTER2("ef->rela");
1461 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA);
1462 TSEXIT2("ef->rela");
1463 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL);
1464 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA);
1473 relocate_file(elf_file_t ef)
1477 error = relocate_file1(ef, elf_lookup, elf_reloc, false);
1479 error = relocate_file1(ef, elf_lookup, elf_reloc, true);
1484 * SysV hash function for symbol table lookup. It is specified by the
1488 elf_hash(const char *name)
1490 const unsigned char *p = (const unsigned char *)name;
1493 while (*p != '\0') {
1494 h = (h << 4) + *p++;
1495 h ^= (h >> 24) & 0xf0;
1497 return (h & 0x0fffffff);
1501 link_elf_lookup_symbol1(linker_file_t lf, const char *name, c_linker_sym_t *sym,
1504 elf_file_t ef = (elf_file_t) lf;
1505 unsigned long symnum;
1506 const Elf_Sym* symp;
1510 /* If we don't have a hash, bail. */
1511 if (ef->buckets == NULL || ef->nbuckets == 0) {
1512 printf("link_elf_lookup_symbol: missing symbol hash table\n");
1516 /* First, search hashed global symbols */
1517 hash = elf_hash(name);
1518 symnum = ef->buckets[hash % ef->nbuckets];
1520 while (symnum != STN_UNDEF) {
1521 if (symnum >= ef->nchains) {
1522 printf("%s: corrupt symbol table\n", __func__);
1526 symp = ef->symtab + symnum;
1527 if (symp->st_name == 0) {
1528 printf("%s: corrupt symbol table\n", __func__);
1532 strp = ef->strtab + symp->st_name;
1534 if (strcmp(name, strp) == 0) {
1535 if (symp->st_shndx != SHN_UNDEF ||
1536 (symp->st_value != 0 &&
1537 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1538 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1540 ELF_ST_BIND(symp->st_info) != STB_LOCAL) {
1541 *sym = (c_linker_sym_t) symp;
1548 symnum = ef->chains[symnum];
1555 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1557 if (link_elf_leak_locals)
1558 return (link_elf_lookup_debug_symbol(lf, name, sym));
1559 return (link_elf_lookup_symbol1(lf, name, sym, false));
1563 link_elf_lookup_debug_symbol(linker_file_t lf, const char *name,
1564 c_linker_sym_t *sym)
1566 elf_file_t ef = (elf_file_t)lf;
1567 const Elf_Sym* symp;
1571 if (link_elf_lookup_symbol1(lf, name, sym, true) == 0)
1574 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1575 strp = ef->ddbstrtab + symp->st_name;
1576 if (strcmp(name, strp) == 0) {
1577 if (symp->st_shndx != SHN_UNDEF ||
1578 (symp->st_value != 0 &&
1579 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1580 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1581 *sym = (c_linker_sym_t) symp;
1592 link_elf_symbol_values1(linker_file_t lf, c_linker_sym_t sym,
1593 linker_symval_t *symval, bool see_local)
1599 ef = (elf_file_t)lf;
1600 es = (const Elf_Sym *)sym;
1601 if (es >= ef->symtab && es < ef->symtab + ef->nchains) {
1602 if (!see_local && ELF_ST_BIND(es->st_info) == STB_LOCAL)
1604 symval->name = ef->strtab + es->st_name;
1605 val = (caddr_t)ef->address + es->st_value;
1606 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1607 val = ((caddr_t (*)(void))val)();
1608 symval->value = val;
1609 symval->size = es->st_size;
1616 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1617 linker_symval_t *symval)
1619 if (link_elf_leak_locals)
1620 return (link_elf_debug_symbol_values(lf, sym, symval));
1621 return (link_elf_symbol_values1(lf, sym, symval, false));
1625 link_elf_debug_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1626 linker_symval_t *symval)
1628 elf_file_t ef = (elf_file_t)lf;
1629 const Elf_Sym *es = (const Elf_Sym *)sym;
1632 if (link_elf_symbol_values1(lf, sym, symval, true) == 0)
1634 if (ef->symtab == ef->ddbsymtab)
1637 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1638 symval->name = ef->ddbstrtab + es->st_name;
1639 val = (caddr_t)ef->address + es->st_value;
1640 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1641 val = ((caddr_t (*)(void))val)();
1642 symval->value = val;
1643 symval->size = es->st_size;
1650 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1651 c_linker_sym_t *sym, long *diffp)
1653 elf_file_t ef = (elf_file_t)lf;
1654 u_long off = (uintptr_t)(void *)value;
1658 const Elf_Sym *best = NULL;
1661 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1662 if (es->st_name == 0)
1664 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1665 if (off >= st_value) {
1666 if (off - st_value < diff) {
1667 diff = off - st_value;
1671 } else if (off - st_value == diff) {
1680 *sym = (c_linker_sym_t) best;
1686 * Look up a linker set on an ELF system.
1689 link_elf_lookup_set(linker_file_t lf, const char *name,
1690 void ***startp, void ***stopp, int *countp)
1693 linker_symval_t symval;
1695 void **start, **stop;
1696 int len, error = 0, count;
1698 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1699 setsym = malloc(len, M_LINKER, M_WAITOK);
1701 /* get address of first entry */
1702 snprintf(setsym, len, "%s%s", "__start_set_", name);
1703 error = link_elf_lookup_symbol(lf, setsym, &sym);
1706 link_elf_symbol_values(lf, sym, &symval);
1707 if (symval.value == 0) {
1711 start = (void **)symval.value;
1713 /* get address of last entry */
1714 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1715 error = link_elf_lookup_symbol(lf, setsym, &sym);
1718 link_elf_symbol_values(lf, sym, &symval);
1719 if (symval.value == 0) {
1723 stop = (void **)symval.value;
1725 /* and the number of entries */
1726 count = stop - start;
1737 free(setsym, M_LINKER);
1742 link_elf_each_function_name(linker_file_t file,
1743 int (*callback)(const char *, void *), void *opaque)
1745 elf_file_t ef = (elf_file_t)file;
1746 const Elf_Sym *symp;
1749 /* Exhaustive search */
1750 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1751 if (symp->st_value != 0 &&
1752 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1753 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1754 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1763 link_elf_each_function_nameval(linker_file_t file,
1764 linker_function_nameval_callback_t callback, void *opaque)
1766 linker_symval_t symval;
1767 elf_file_t ef = (elf_file_t)file;
1768 const Elf_Sym *symp;
1771 /* Exhaustive search */
1772 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1773 if (symp->st_value != 0 &&
1774 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1775 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1776 error = link_elf_debug_symbol_values(file,
1777 (c_linker_sym_t) symp, &symval);
1779 error = callback(file, i, &symval, opaque);
1788 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1790 elf_file_t ef = (elf_file_t)lf;
1792 if (symidx >= ef->nchains)
1794 return (ef->symtab + symidx);
1798 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1800 elf_file_t ef = (elf_file_t)lf;
1803 if (symidx >= ef->nchains)
1805 sym = ef->symtab + symidx;
1806 return (ef->strtab + sym->st_name);
1810 * Symbol lookup function that can be used when the symbol index is known (ie
1811 * in relocations). It uses the symbol index instead of doing a fully fledged
1812 * hash table based lookup when such is valid. For example for local symbols.
1813 * This is not only more efficient, it's also more correct. It's not always
1814 * the case that the symbol can be found through the hash table.
1817 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1819 elf_file_t ef = (elf_file_t)lf;
1822 Elf_Addr addr, start, base;
1824 /* Don't even try to lookup the symbol if the index is bogus. */
1825 if (symidx >= ef->nchains) {
1830 sym = ef->symtab + symidx;
1833 * Don't do a full lookup when the symbol is local. It may even
1834 * fail because it may not be found through the hash table.
1836 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1837 /* Force lookup failure when we have an insanity. */
1838 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1842 *res = ((Elf_Addr)ef->address + sym->st_value);
1847 * XXX we can avoid doing a hash table based lookup for global
1848 * symbols as well. This however is not always valid, so we'll
1849 * just do it the hard way for now. Performance tweaks can
1853 symbol = ef->strtab + sym->st_name;
1855 /* Force a lookup failure if the symbol name is bogus. */
1861 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1862 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1867 if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1868 addr = addr - start + base;
1870 else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1871 addr = addr - start + base;
1878 link_elf_reloc_local(linker_file_t lf)
1880 const Elf_Rel *rellim;
1882 const Elf_Rela *relalim;
1883 const Elf_Rela *rela;
1884 elf_file_t ef = (elf_file_t)lf;
1886 /* Perform relocations without addend if there are any: */
1887 if ((rel = ef->rel) != NULL) {
1888 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1889 while (rel < rellim) {
1890 elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1891 ELF_RELOC_REL, elf_lookup);
1896 /* Perform relocations with addend if there are any: */
1897 if ((rela = ef->rela) != NULL) {
1898 relalim = (const Elf_Rela *)
1899 ((const char *)ef->rela + ef->relasize);
1900 while (rela < relalim) {
1901 elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1902 ELF_RELOC_RELA, elf_lookup);
1909 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1911 elf_file_t ef = (elf_file_t)lf;
1913 *symtab = ef->ddbsymtab;
1915 if (*symtab == NULL)
1918 return (ef->ddbsymcnt);
1922 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1924 elf_file_t ef = (elf_file_t)lf;
1926 *strtab = ef->ddbstrtab;
1928 if (*strtab == NULL)
1931 return (ef->ddbstrcnt);
1936 link_elf_propagate_vnets(linker_file_t lf)
1938 elf_file_t ef = (elf_file_t)lf;
1941 if (ef->vnet_base != 0) {
1942 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
1943 vnet_data_copy((void *)ef->vnet_base, size);
1948 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) || defined(__powerpc__)
1950 * Use this lookup routine when performing relocations early during boot.
1951 * The generic lookup routine depends on kobj, which is not initialized
1955 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused,
1959 const Elf_Sym *symp;
1962 ef = (elf_file_t)lf;
1963 symp = ef->symtab + symidx;
1964 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) {
1965 val = (caddr_t)ef->address + symp->st_value;
1966 *res = ((Elf_Addr (*)(void))val)();
1973 link_elf_ireloc(caddr_t kmdp)
1975 struct elf_file eff;
1981 bzero_early(ef, sizeof(*ef));
1984 ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
1986 #ifdef RELOCATABLE_KERNEL
1987 ef->address = (caddr_t) (__startkernel - KERNBASE);
1993 link_elf_preload_parse_symbols(ef);
1994 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true);
1998 #if defined(__aarch64__) || defined(__amd64__)
2000 link_elf_late_ireloc(void)
2004 KASSERT(linker_kernel_file != NULL,
2005 ("link_elf_late_ireloc: No kernel linker file found"));
2006 ef = (elf_file_t)linker_kernel_file;
2008 relocate_file1(ef, elf_lookup_ifunc, elf_reloc_late, true);