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 *);
163 static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
165 static kobj_method_t link_elf_methods[] = {
166 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
167 KOBJMETHOD(linker_lookup_debug_symbol, link_elf_lookup_debug_symbol),
168 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
169 KOBJMETHOD(linker_debug_symbol_values, link_elf_debug_symbol_values),
170 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
171 KOBJMETHOD(linker_unload, link_elf_unload_file),
172 KOBJMETHOD(linker_load_file, link_elf_load_file),
173 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
174 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
175 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
176 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
177 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
178 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
179 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
180 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
184 static struct linker_class link_elf_class = {
185 #if ELF_TARG_CLASS == ELFCLASS32
190 link_elf_methods, sizeof(struct elf_file)
193 static bool link_elf_leak_locals = true;
194 SYSCTL_BOOL(_debug, OID_AUTO, link_elf_leak_locals,
195 CTLFLAG_RWTUN, &link_elf_leak_locals, 0,
196 "Allow local symbols to participate in global module symbol resolution");
198 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase,
199 const void *data, int type, elf_lookup_fn lookup);
201 static int parse_dynamic(elf_file_t);
202 static int relocate_file(elf_file_t);
203 static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup,
204 elf_reloc_fn reloc, bool ifuncs);
205 static int link_elf_preload_parse_symbols(elf_file_t);
207 static struct elf_set_head set_pcpu_list;
209 static struct elf_set_head set_vnet_list;
213 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
215 struct elf_set *set, *iter;
217 set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
218 set->es_start = start;
222 TAILQ_FOREACH(iter, list, es_link) {
223 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
224 (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
225 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
226 (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
227 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
229 if (iter->es_start > set->es_start) {
230 TAILQ_INSERT_BEFORE(iter, set, es_link);
236 TAILQ_INSERT_TAIL(list, set, es_link);
240 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
244 TAILQ_FOREACH(set, list, es_link) {
245 if (addr < set->es_start)
247 if (addr < set->es_stop) {
248 *start = set->es_start;
249 *base = set->es_base;
258 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
262 TAILQ_FOREACH(set, list, es_link) {
263 if (start < set->es_start)
265 if (start == set->es_start) {
266 TAILQ_REMOVE(list, set, es_link);
271 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
276 static void r_debug_state(struct r_debug *, struct link_map *);
279 * A list of loaded modules for GDB to use for loading symbols.
281 struct r_debug r_debug;
283 #define GDB_STATE(s) do { \
284 r_debug.r_state = s; r_debug_state(NULL, NULL); \
288 * Function for the debugger to set a breakpoint on to gain control.
291 r_debug_state(struct r_debug *dummy_one __unused,
292 struct link_map *dummy_two __unused)
297 link_elf_add_gdb(struct link_map *l)
299 struct link_map *prev;
303 if (r_debug.r_map == NULL) {
308 /* Append to list. */
309 for (prev = r_debug.r_map;
310 prev->l_next != NULL;
319 link_elf_delete_gdb(struct link_map *l)
321 if (l->l_prev == NULL) {
323 if ((r_debug.r_map = l->l_next) != NULL)
324 l->l_next->l_prev = NULL;
326 /* Remove any but first. */
327 if ((l->l_prev->l_next = l->l_next) != NULL)
328 l->l_next->l_prev = l->l_prev;
334 * The kernel symbol table starts here.
336 extern struct _dynamic _DYNAMIC;
339 link_elf_error(const char *filename, const char *s)
341 if (filename == NULL)
342 printf("kldload: %s\n", s);
344 printf("kldload: %s: %s\n", filename, s);
348 link_elf_invoke_ctors(caddr_t addr, size_t size)
353 if (addr == NULL || size == 0)
355 cnt = size / sizeof(*ctor);
357 for (i = 0; i < cnt; i++) {
364 * Actions performed after linking/loading both the preloaded kernel and any
365 * modules; whether preloaded or dynamicly loaded.
368 link_elf_link_common_finish(linker_file_t lf)
371 elf_file_t ef = (elf_file_t)lf;
376 /* Notify MD code that a module is being loaded. */
377 error = elf_cpu_load_file(lf);
383 ef->gdb.l_addr = lf->address;
384 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
385 strcpy(newfilename, lf->filename);
386 ef->gdb.l_name = newfilename;
387 ef->gdb.l_ld = ef->dynamic;
388 link_elf_add_gdb(&ef->gdb);
389 GDB_STATE(RT_CONSISTENT);
393 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
397 #ifdef RELOCATABLE_KERNEL
399 * __startkernel and __endkernel are symbols set up as relocation canaries.
401 * They are defined in locore to reference linker script symbols at the
402 * beginning and end of the LOAD area. This has the desired side effect of
403 * giving us variables that have relative relocations pointing at them, so
404 * relocation of the kernel object will cause the variables to be updated
405 * automatically by the runtime linker when we initialize.
407 * There are two main reasons to relocate the kernel:
408 * 1) If the loader needed to load the kernel at an alternate load address.
409 * 2) If the kernel is switching address spaces on machines like POWER9
410 * under Radix where the high bits of the effective address are used to
411 * differentiate between hypervisor, host, guest, and problem state.
413 extern vm_offset_t __startkernel, __endkernel;
416 static unsigned long kern_relbase = KERNBASE;
418 SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD,
419 SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address");
420 SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD,
421 &kern_relbase, 0, "Kernel relocated base address");
424 link_elf_init(void* arg)
427 Elf_Addr *ctors_addrp;
428 Elf_Size *ctors_sizep;
429 caddr_t modptr, baseptr, sizeptr;
433 linker_add_class(&link_elf_class);
435 dp = (Elf_Dyn *)&_DYNAMIC;
437 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
439 modptr = preload_search_by_type("elf kernel");
440 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
443 linker_kernel_file = linker_make_file(modname, &link_elf_class);
444 if (linker_kernel_file == NULL)
445 panic("%s: Can't create linker structures for kernel",
448 ef = (elf_file_t) linker_kernel_file;
450 #ifdef RELOCATABLE_KERNEL
451 /* Compute relative displacement */
452 ef->address = (caddr_t) (__startkernel - KERNBASE);
456 #ifdef SPARSE_MAPPING
463 #ifdef RELOCATABLE_KERNEL
464 linker_kernel_file->address = (caddr_t)__startkernel;
465 linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
466 kern_relbase = (unsigned long)__startkernel;
468 linker_kernel_file->address += KERNBASE;
469 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
472 if (modptr != NULL) {
474 baseptr = preload_search_info(modptr, MODINFO_ADDR);
476 linker_kernel_file->address = *(caddr_t *)baseptr;
477 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
479 linker_kernel_file->size = *(size_t *)sizeptr;
480 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
481 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
482 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
483 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
484 if (ctors_addrp != NULL && ctors_sizep != NULL) {
485 linker_kernel_file->ctors_addr = ef->address +
487 linker_kernel_file->ctors_size = *ctors_sizep;
490 (void)link_elf_preload_parse_symbols(ef);
493 r_debug.r_map = NULL;
494 r_debug.r_brk = r_debug_state;
495 r_debug.r_state = RT_CONSISTENT;
498 (void)link_elf_link_common_finish(linker_kernel_file);
499 linker_kernel_file->flags |= LINKER_FILE_LINKED;
500 TAILQ_INIT(&set_pcpu_list);
502 TAILQ_INIT(&set_vnet_list);
506 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL);
509 link_elf_preload_parse_symbols(elf_file_t ef)
512 caddr_t ssym, esym, base;
518 if (ef->modptr == NULL)
520 pointer = preload_search_info(ef->modptr,
521 MODINFO_METADATA | MODINFOMD_SSYM);
524 ssym = *(caddr_t *)pointer;
525 pointer = preload_search_info(ef->modptr,
526 MODINFO_METADATA | MODINFOMD_ESYM);
529 esym = *(caddr_t *)pointer;
533 symcnt = *(long *)base;
534 base += sizeof(long);
535 symtab = (Elf_Sym *)base;
536 base += roundup(symcnt, sizeof(long));
538 if (base > esym || base < ssym) {
539 printf("Symbols are corrupt!\n");
543 strcnt = *(long *)base;
544 base += sizeof(long);
546 base += roundup(strcnt, sizeof(long));
548 if (base > esym || base < ssym) {
549 printf("Symbols are corrupt!\n");
553 ef->ddbsymtab = symtab;
554 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
555 ef->ddbstrtab = strtab;
556 ef->ddbstrcnt = strcnt;
562 parse_dynamic(elf_file_t ef)
565 int plttype = DT_REL;
567 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
571 /* From src/libexec/rtld-elf/rtld.c */
572 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
573 (ef->address + dp->d_un.d_ptr);
574 ef->nbuckets = hashtab[0];
575 ef->nchains = hashtab[1];
576 ef->buckets = hashtab + 2;
577 ef->chains = ef->buckets + ef->nbuckets;
581 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
584 ef->strsz = dp->d_un.d_val;
587 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
590 if (dp->d_un.d_val != sizeof(Elf_Sym))
594 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
597 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
600 ef->relsize = dp->d_un.d_val;
603 if (dp->d_un.d_val != sizeof(Elf_Rel))
607 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
610 ef->pltrelsize = dp->d_un.d_val;
613 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
616 ef->relasize = dp->d_un.d_val;
619 if (dp->d_un.d_val != sizeof(Elf_Rela))
623 plttype = dp->d_un.d_val;
624 if (plttype != DT_REL && plttype != DT_RELA)
629 dp->d_un.d_ptr = (Elf_Addr)&r_debug;
635 if (plttype == DT_RELA) {
636 ef->pltrela = (const Elf_Rela *)ef->pltrel;
638 ef->pltrelasize = ef->pltrelsize;
642 ef->ddbsymtab = ef->symtab;
643 ef->ddbsymcnt = ef->nchains;
644 ef->ddbstrtab = ef->strtab;
645 ef->ddbstrcnt = ef->strsz;
647 return elf_cpu_parse_dynamic(ef->address, ef->dynamic);
650 #define LS_PADDING 0x90909090
652 parse_dpcpu(elf_file_t ef)
655 #if defined(__i386__)
661 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
662 (void ***)&ef->pcpu_stop, NULL);
663 /* Error just means there is no pcpu set to relocate. */
666 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start;
670 #if defined(__i386__)
671 /* In case we do find __start/stop_set_ symbols double-check. */
673 uprintf("Kernel module '%s' must be recompiled with "
674 "linker script\n", ef->lf.pathname);
678 /* Padding from linker-script correct? */
679 pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad));
680 if (pad != LS_PADDING) {
681 uprintf("Kernel module '%s' must be recompiled with "
682 "linker script, invalid padding %#04x (%#04x)\n",
683 ef->lf.pathname, pad, LS_PADDING);
686 /* If we only have valid padding, nothing to do. */
691 * Allocate space in the primary pcpu area. Copy in our
692 * initialization from the data section and then initialize
693 * all per-cpu storage from that.
695 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size);
696 if (ef->pcpu_base == 0) {
697 printf("%s: pcpu module space is out of space; "
698 "cannot allocate %d for %s\n",
699 __func__, size, ef->lf.pathname);
702 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size);
703 dpcpu_copy((void *)ef->pcpu_base, size);
704 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
712 parse_vnet(elf_file_t ef)
715 #if defined(__i386__)
721 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
722 (void ***)&ef->vnet_stop, NULL);
723 /* Error just means there is no vnet data set to relocate. */
726 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
730 #if defined(__i386__)
731 /* In case we do find __start/stop_set_ symbols double-check. */
733 uprintf("Kernel module '%s' must be recompiled with "
734 "linker script\n", ef->lf.pathname);
738 /* Padding from linker-script correct? */
739 pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad));
740 if (pad != LS_PADDING) {
741 uprintf("Kernel module '%s' must be recompiled with "
742 "linker script, invalid padding %#04x (%#04x)\n",
743 ef->lf.pathname, pad, LS_PADDING);
746 /* If we only have valid padding, nothing to do. */
751 * Allocate space in the primary vnet area. Copy in our
752 * initialization from the data section and then initialize
753 * all per-vnet storage from that.
755 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size);
756 if (ef->vnet_base == 0) {
757 printf("%s: vnet module space is out of space; "
758 "cannot allocate %d for %s\n",
759 __func__, size, ef->lf.pathname);
762 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size);
763 vnet_data_copy((void *)ef->vnet_base, size);
764 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
773 * Apply the specified protection to the loadable segments of a preloaded linker
777 preload_protect(elf_file_t ef, vm_prot_t prot)
779 #if defined(__aarch64__) || defined(__amd64__)
781 Elf_Phdr *phdr, *phlimit;
786 hdr = (Elf_Ehdr *)ef->address;
787 phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff);
788 phlimit = phdr + hdr->e_phnum;
789 for (; phdr < phlimit; phdr++) {
790 if (phdr->p_type != PT_LOAD)
793 nprot = prot | VM_PROT_READ;
794 if ((phdr->p_flags & PF_W) != 0)
795 nprot |= VM_PROT_WRITE;
796 if ((phdr->p_flags & PF_X) != 0)
797 nprot |= VM_PROT_EXECUTE;
798 error = pmap_change_prot((vm_offset_t)ef->address +
799 phdr->p_vaddr, round_page(phdr->p_memsz), nprot);
811 * Locate the ARM exception/unwind table info for DDB and stack(9) use by
812 * searching for the section header that describes it. There may be no unwind
813 * info, for example in a module containing only data.
816 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr)
820 for (i = 0; i < nhdr; i++) {
821 if (shdr[i].sh_type == SHT_ARM_EXIDX) {
822 lf->exidx_addr = shdr[i].sh_addr + lf->address;
823 lf->exidx_size = shdr[i].sh_size;
830 * Locate the section headers metadata in a preloaded module, then use it to
831 * locate the exception/unwind table in the module. The size of the metadata
832 * block is stored in a uint32 word immediately before the data itself, and a
833 * comment in preload_search_info() says it is safe to rely on that.
836 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr)
842 modinfo = (uint32_t *)preload_search_info(modptr,
843 MODINFO_METADATA | MODINFOMD_SHDR);
844 if (modinfo != NULL) {
845 shdr = (Elf_Shdr *)modinfo;
846 nhdr = modinfo[-1] / sizeof(Elf_Shdr);
847 link_elf_locate_exidx(lf, shdr, nhdr);
854 link_elf_link_preload(linker_class_t cls, const char *filename,
855 linker_file_t *result)
857 Elf_Addr *ctors_addrp;
858 Elf_Size *ctors_sizep;
859 caddr_t modptr, baseptr, sizeptr, dynptr;
866 /* Look to see if we have the file preloaded */
867 modptr = preload_search_by_name(filename);
871 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
872 baseptr = preload_search_info(modptr, MODINFO_ADDR);
873 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
874 dynptr = preload_search_info(modptr,
875 MODINFO_METADATA | MODINFOMD_DYNAMIC);
877 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
878 strcmp(type, "elf module") != 0))
880 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
883 lf = linker_make_file(filename, &link_elf_class);
887 ef = (elf_file_t) lf;
890 ef->address = *(caddr_t *)baseptr;
891 #ifdef SPARSE_MAPPING
894 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
895 ef->dynamic = (Elf_Dyn *)dp;
896 lf->address = ef->address;
897 lf->size = *(size_t *)sizeptr;
899 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
900 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
901 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
902 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
903 if (ctors_addrp != NULL && ctors_sizep != NULL) {
904 lf->ctors_addr = ef->address + *ctors_addrp;
905 lf->ctors_size = *ctors_sizep;
909 link_elf_locate_exidx_preload(lf, modptr);
912 error = parse_dynamic(ef);
914 error = parse_dpcpu(ef);
917 error = parse_vnet(ef);
920 error = preload_protect(ef, VM_PROT_ALL);
922 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
925 link_elf_reloc_local(lf);
931 link_elf_link_preload_finish(linker_file_t lf)
936 ef = (elf_file_t) lf;
937 error = relocate_file(ef);
939 error = preload_protect(ef, VM_PROT_NONE);
942 (void)link_elf_preload_parse_symbols(ef);
944 return (link_elf_link_common_finish(lf));
948 link_elf_load_file(linker_class_t cls, const char* filename,
949 linker_file_t* result)
952 struct thread* td = curthread; /* XXX */
954 caddr_t firstpage, segbase;
958 Elf_Phdr *segs[MAXSEGS];
964 Elf_Addr base_vlimit;
982 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename);
984 error = vn_open(&nd, &flags, 0, NULL);
988 if (nd.ni_vp->v_type != VREG) {
994 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
1002 * Read the elf header from the file.
1004 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
1005 hdr = (Elf_Ehdr *)firstpage;
1006 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
1007 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1009 nbytes = PAGE_SIZE - resid;
1013 if (!IS_ELF(*hdr)) {
1018 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
1019 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
1020 link_elf_error(filename, "Unsupported file layout");
1024 if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
1025 hdr->e_version != EV_CURRENT) {
1026 link_elf_error(filename, "Unsupported file version");
1030 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
1034 if (hdr->e_machine != ELF_TARG_MACH) {
1035 link_elf_error(filename, "Unsupported machine");
1041 * We rely on the program header being in the first page.
1042 * This is not strictly required by the ABI specification, but
1043 * it seems to always true in practice. And, it simplifies
1044 * things considerably.
1046 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
1047 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
1048 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
1049 link_elf_error(filename, "Unreadable program headers");
1052 * Scan the program header entries, and save key information.
1054 * We rely on there being exactly two load segments, text and data,
1057 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
1058 phlimit = phdr + hdr->e_phnum;
1061 while (phdr < phlimit) {
1062 switch (phdr->p_type) {
1064 if (nsegs == MAXSEGS) {
1065 link_elf_error(filename, "Too many sections");
1070 * XXX: We just trust they come in right order ??
1087 if (phdyn == NULL) {
1088 link_elf_error(filename, "Object is not dynamically-linked");
1093 link_elf_error(filename, "No sections");
1099 * Allocate the entire address space of the object, to stake
1100 * out our contiguous region, and to establish the base
1101 * address for relocation.
1103 base_vaddr = trunc_page(segs[0]->p_vaddr);
1104 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
1105 segs[nsegs - 1]->p_memsz);
1106 mapsize = base_vlimit - base_vaddr;
1108 lf = linker_make_file(filename, &link_elf_class);
1114 ef = (elf_file_t) lf;
1115 #ifdef SPARSE_MAPPING
1116 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, mapsize, VM_PROT_ALL,
1117 0, thread0.td_ucred);
1118 if (ef->object == NULL) {
1123 mapbase = (caddr_t)KERNBASE;
1125 mapbase = (caddr_t)vm_map_min(kernel_map);
1128 * Mapping protections are downgraded after relocation processing.
1130 error = vm_map_find(kernel_map, ef->object, 0,
1131 (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE,
1132 VM_PROT_ALL, VM_PROT_ALL, 0);
1134 vm_object_deallocate(ef->object);
1139 mapbase = malloc_exec(mapsize, M_LINKER, M_WAITOK);
1141 ef->address = mapbase;
1144 * Read the text and data sections and zero the bss.
1146 for (i = 0; i < nsegs; i++) {
1147 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1149 #ifdef SPARSE_MAPPING
1151 * Consecutive segments may have different mapping permissions,
1152 * so be strict and verify that their mappings do not overlap.
1154 if (((vm_offset_t)segbase & PAGE_MASK) != 0) {
1159 error = vm_map_wire(kernel_map,
1160 (vm_offset_t)segbase,
1161 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1162 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
1163 if (error != KERN_SUCCESS) {
1169 error = vn_rdwr(UIO_READ, nd.ni_vp,
1170 segbase, segs[i]->p_filesz, segs[i]->p_offset,
1171 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1175 bzero(segbase + segs[i]->p_filesz,
1176 segs[i]->p_memsz - segs[i]->p_filesz);
1179 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
1181 lf->address = ef->address;
1184 error = parse_dynamic(ef);
1187 error = parse_dpcpu(ef);
1191 error = parse_vnet(ef);
1195 link_elf_reloc_local(lf);
1197 VOP_UNLOCK(nd.ni_vp);
1198 error = linker_load_dependencies(lf);
1199 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1202 error = relocate_file(ef);
1206 #ifdef SPARSE_MAPPING
1208 * Downgrade permissions on text segment mappings now that relocation
1209 * processing is complete. Restrict permissions on read-only segments.
1211 for (i = 0; i < nsegs; i++) {
1214 if (segs[i]->p_type != PT_LOAD)
1217 prot = VM_PROT_READ;
1218 if ((segs[i]->p_flags & PF_W) != 0)
1219 prot |= VM_PROT_WRITE;
1220 if ((segs[i]->p_flags & PF_X) != 0)
1221 prot |= VM_PROT_EXECUTE;
1222 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1223 error = vm_map_protect(kernel_map,
1224 (vm_offset_t)segbase,
1225 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1226 prot, 0, VM_MAP_PROTECT_SET_PROT);
1227 if (error != KERN_SUCCESS) {
1235 * Try and load the symbol table if it's present. (you can
1238 nbytes = hdr->e_shnum * hdr->e_shentsize;
1239 if (nbytes == 0 || hdr->e_shoff == 0)
1241 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1242 error = vn_rdwr(UIO_READ, nd.ni_vp,
1243 (caddr_t)shdr, nbytes, hdr->e_shoff,
1244 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1249 /* Read section string table */
1250 shstrindex = hdr->e_shstrndx;
1251 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1252 shdr[shstrindex].sh_size != 0) {
1253 nbytes = shdr[shstrindex].sh_size;
1254 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1255 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1256 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1257 td->td_ucred, NOCRED, &resid, td);
1264 for (i = 0; i < hdr->e_shnum; i++) {
1265 if (shdr[i].sh_type == SHT_SYMTAB) {
1267 symstrindex = shdr[i].sh_link;
1268 } else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1269 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1270 /* Record relocated address and size of .ctors. */
1271 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1272 lf->ctors_size = shdr[i].sh_size;
1275 if (symtabindex < 0 || symstrindex < 0)
1278 symcnt = shdr[symtabindex].sh_size;
1279 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1280 strcnt = shdr[symstrindex].sh_size;
1281 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1283 error = vn_rdwr(UIO_READ, nd.ni_vp,
1284 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1285 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1289 error = vn_rdwr(UIO_READ, nd.ni_vp,
1290 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1291 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1296 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1297 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1298 ef->ddbstrcnt = strcnt;
1299 ef->ddbstrtab = ef->strbase;
1304 link_elf_locate_exidx(lf, shdr, hdr->e_shnum);
1307 error = link_elf_link_common_finish(lf);
1314 VOP_UNLOCK(nd.ni_vp);
1315 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1316 if (error != 0 && lf != NULL)
1317 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1318 free(shdr, M_LINKER);
1319 free(firstpage, M_LINKER);
1320 free(shstrs, M_LINKER);
1326 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1330 KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class,
1331 ("elf_relocaddr: unexpected linker file %p", lf));
1333 ef = (elf_file_t)lf;
1334 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1335 return ((x - ef->pcpu_start) + ef->pcpu_base);
1337 if (x >= ef->vnet_start && x < ef->vnet_stop)
1338 return ((x - ef->vnet_start) + ef->vnet_base);
1344 link_elf_unload_file(linker_file_t file)
1346 elf_file_t ef = (elf_file_t) file;
1348 if (ef->pcpu_base != 0) {
1349 dpcpu_free((void *)ef->pcpu_base,
1350 ef->pcpu_stop - ef->pcpu_start);
1351 elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1354 if (ef->vnet_base != 0) {
1355 vnet_data_free((void *)ef->vnet_base,
1356 ef->vnet_stop - ef->vnet_start);
1357 elf_set_delete(&set_vnet_list, ef->vnet_start);
1361 if (ef->gdb.l_ld != NULL) {
1362 GDB_STATE(RT_DELETE);
1363 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1364 link_elf_delete_gdb(&ef->gdb);
1365 GDB_STATE(RT_CONSISTENT);
1369 /* Notify MD code that a module is being unloaded. */
1370 elf_cpu_unload_file(file);
1372 if (ef->preloaded) {
1373 link_elf_unload_preload(file);
1377 #ifdef SPARSE_MAPPING
1378 if (ef->object != NULL) {
1379 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1380 (vm_offset_t) ef->address
1381 + (ef->object->size << PAGE_SHIFT));
1384 free(ef->address, M_LINKER);
1386 free(ef->symbase, M_LINKER);
1387 free(ef->strbase, M_LINKER);
1388 free(ef->ctftab, M_LINKER);
1389 free(ef->ctfoff, M_LINKER);
1390 free(ef->typoff, M_LINKER);
1394 link_elf_unload_preload(linker_file_t file)
1397 if (file->pathname != NULL)
1398 preload_delete_name(file->pathname);
1402 symbol_name(elf_file_t ef, Elf_Size r_info)
1406 if (ELF_R_SYM(r_info)) {
1407 ref = ef->symtab + ELF_R_SYM(r_info);
1408 return (ef->strtab + ref->st_name);
1414 symbol_type(elf_file_t ef, Elf_Size r_info)
1418 if (ELF_R_SYM(r_info)) {
1419 ref = ef->symtab + ELF_R_SYM(r_info);
1420 return (ELF_ST_TYPE(ref->st_info));
1422 return (STT_NOTYPE);
1426 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc,
1430 const Elf_Rela *rela;
1431 const char *symname;
1434 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \
1435 for ((iter) = (tbl); (iter) != NULL && \
1436 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \
1437 if ((symbol_type(ef, (iter)->r_info) == \
1439 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \
1441 if (reloc(&ef->lf, (Elf_Addr)ef->address, \
1442 (iter), (type), lookup)) { \
1443 symname = symbol_name(ef, (iter)->r_info); \
1444 printf("link_elf: symbol %s undefined\n", \
1451 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL);
1452 TSENTER2("ef->rela");
1453 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA);
1454 TSEXIT2("ef->rela");
1455 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL);
1456 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA);
1465 relocate_file(elf_file_t ef)
1469 error = relocate_file1(ef, elf_lookup, elf_reloc, false);
1471 error = relocate_file1(ef, elf_lookup, elf_reloc, true);
1476 * SysV hash function for symbol table lookup. It is specified by the
1480 elf_hash(const char *name)
1482 const unsigned char *p = (const unsigned char *)name;
1485 while (*p != '\0') {
1486 h = (h << 4) + *p++;
1487 h ^= (h >> 24) & 0xf0;
1489 return (h & 0x0fffffff);
1493 link_elf_lookup_symbol1(linker_file_t lf, const char *name, c_linker_sym_t *sym,
1496 elf_file_t ef = (elf_file_t) lf;
1497 unsigned long symnum;
1498 const Elf_Sym* symp;
1502 /* If we don't have a hash, bail. */
1503 if (ef->buckets == NULL || ef->nbuckets == 0) {
1504 printf("link_elf_lookup_symbol: missing symbol hash table\n");
1508 /* First, search hashed global symbols */
1509 hash = elf_hash(name);
1510 symnum = ef->buckets[hash % ef->nbuckets];
1512 while (symnum != STN_UNDEF) {
1513 if (symnum >= ef->nchains) {
1514 printf("%s: corrupt symbol table\n", __func__);
1518 symp = ef->symtab + symnum;
1519 if (symp->st_name == 0) {
1520 printf("%s: corrupt symbol table\n", __func__);
1524 strp = ef->strtab + symp->st_name;
1526 if (strcmp(name, strp) == 0) {
1527 if (symp->st_shndx != SHN_UNDEF ||
1528 (symp->st_value != 0 &&
1529 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1530 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1532 ELF_ST_BIND(symp->st_info) != STB_LOCAL) {
1533 *sym = (c_linker_sym_t) symp;
1540 symnum = ef->chains[symnum];
1547 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1549 if (link_elf_leak_locals)
1550 return (link_elf_lookup_debug_symbol(lf, name, sym));
1551 return (link_elf_lookup_symbol1(lf, name, sym, false));
1555 link_elf_lookup_debug_symbol(linker_file_t lf, const char *name,
1556 c_linker_sym_t *sym)
1558 elf_file_t ef = (elf_file_t)lf;
1559 const Elf_Sym* symp;
1563 if (link_elf_lookup_symbol1(lf, name, sym, true) == 0)
1566 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1567 strp = ef->ddbstrtab + symp->st_name;
1568 if (strcmp(name, strp) == 0) {
1569 if (symp->st_shndx != SHN_UNDEF ||
1570 (symp->st_value != 0 &&
1571 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1572 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1573 *sym = (c_linker_sym_t) symp;
1584 link_elf_symbol_values1(linker_file_t lf, c_linker_sym_t sym,
1585 linker_symval_t *symval, bool see_local)
1591 ef = (elf_file_t)lf;
1592 es = (const Elf_Sym *)sym;
1593 if (es >= ef->symtab && es < ef->symtab + ef->nchains) {
1594 if (!see_local && ELF_ST_BIND(es->st_info) == STB_LOCAL)
1596 symval->name = ef->strtab + es->st_name;
1597 val = (caddr_t)ef->address + es->st_value;
1598 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1599 val = ((caddr_t (*)(void))val)();
1600 symval->value = val;
1601 symval->size = es->st_size;
1608 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1609 linker_symval_t *symval)
1611 if (link_elf_leak_locals)
1612 return (link_elf_debug_symbol_values(lf, sym, symval));
1613 return (link_elf_symbol_values1(lf, sym, symval, false));
1617 link_elf_debug_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1618 linker_symval_t *symval)
1620 elf_file_t ef = (elf_file_t)lf;
1621 const Elf_Sym *es = (const Elf_Sym *)sym;
1624 if (link_elf_symbol_values1(lf, sym, symval, true) == 0)
1626 if (ef->symtab == ef->ddbsymtab)
1629 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1630 symval->name = ef->ddbstrtab + es->st_name;
1631 val = (caddr_t)ef->address + es->st_value;
1632 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1633 val = ((caddr_t (*)(void))val)();
1634 symval->value = val;
1635 symval->size = es->st_size;
1642 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1643 c_linker_sym_t *sym, long *diffp)
1645 elf_file_t ef = (elf_file_t)lf;
1646 u_long off = (uintptr_t)(void *)value;
1650 const Elf_Sym *best = NULL;
1653 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1654 if (es->st_name == 0)
1656 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1657 if (off >= st_value) {
1658 if (off - st_value < diff) {
1659 diff = off - st_value;
1663 } else if (off - st_value == diff) {
1672 *sym = (c_linker_sym_t) best;
1678 * Look up a linker set on an ELF system.
1681 link_elf_lookup_set(linker_file_t lf, const char *name,
1682 void ***startp, void ***stopp, int *countp)
1685 linker_symval_t symval;
1687 void **start, **stop;
1688 int len, error = 0, count;
1690 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1691 setsym = malloc(len, M_LINKER, M_WAITOK);
1693 /* get address of first entry */
1694 snprintf(setsym, len, "%s%s", "__start_set_", name);
1695 error = link_elf_lookup_symbol(lf, setsym, &sym);
1698 link_elf_symbol_values(lf, sym, &symval);
1699 if (symval.value == 0) {
1703 start = (void **)symval.value;
1705 /* get address of last entry */
1706 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1707 error = link_elf_lookup_symbol(lf, setsym, &sym);
1710 link_elf_symbol_values(lf, sym, &symval);
1711 if (symval.value == 0) {
1715 stop = (void **)symval.value;
1717 /* and the number of entries */
1718 count = stop - start;
1729 free(setsym, M_LINKER);
1734 link_elf_each_function_name(linker_file_t file,
1735 int (*callback)(const char *, void *), void *opaque)
1737 elf_file_t ef = (elf_file_t)file;
1738 const Elf_Sym *symp;
1741 /* Exhaustive search */
1742 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1743 if (symp->st_value != 0 &&
1744 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1745 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1746 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1755 link_elf_each_function_nameval(linker_file_t file,
1756 linker_function_nameval_callback_t callback, void *opaque)
1758 linker_symval_t symval;
1759 elf_file_t ef = (elf_file_t)file;
1760 const Elf_Sym *symp;
1763 /* Exhaustive search */
1764 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1765 if (symp->st_value != 0 &&
1766 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1767 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1768 error = link_elf_debug_symbol_values(file,
1769 (c_linker_sym_t) symp, &symval);
1771 error = callback(file, i, &symval, opaque);
1780 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1782 elf_file_t ef = (elf_file_t)lf;
1784 if (symidx >= ef->nchains)
1786 return (ef->symtab + symidx);
1790 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1792 elf_file_t ef = (elf_file_t)lf;
1795 if (symidx >= ef->nchains)
1797 sym = ef->symtab + symidx;
1798 return (ef->strtab + sym->st_name);
1802 * Symbol lookup function that can be used when the symbol index is known (ie
1803 * in relocations). It uses the symbol index instead of doing a fully fledged
1804 * hash table based lookup when such is valid. For example for local symbols.
1805 * This is not only more efficient, it's also more correct. It's not always
1806 * the case that the symbol can be found through the hash table.
1809 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1811 elf_file_t ef = (elf_file_t)lf;
1814 Elf_Addr addr, start, base;
1816 /* Don't even try to lookup the symbol if the index is bogus. */
1817 if (symidx >= ef->nchains) {
1822 sym = ef->symtab + symidx;
1825 * Don't do a full lookup when the symbol is local. It may even
1826 * fail because it may not be found through the hash table.
1828 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1829 /* Force lookup failure when we have an insanity. */
1830 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1834 *res = ((Elf_Addr)ef->address + sym->st_value);
1839 * XXX we can avoid doing a hash table based lookup for global
1840 * symbols as well. This however is not always valid, so we'll
1841 * just do it the hard way for now. Performance tweaks can
1845 symbol = ef->strtab + sym->st_name;
1847 /* Force a lookup failure if the symbol name is bogus. */
1853 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1854 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1859 if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1860 addr = addr - start + base;
1862 else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1863 addr = addr - start + base;
1870 link_elf_reloc_local(linker_file_t lf)
1872 const Elf_Rel *rellim;
1874 const Elf_Rela *relalim;
1875 const Elf_Rela *rela;
1876 elf_file_t ef = (elf_file_t)lf;
1878 /* Perform relocations without addend if there are any: */
1879 if ((rel = ef->rel) != NULL) {
1880 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1881 while (rel < rellim) {
1882 elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1883 ELF_RELOC_REL, elf_lookup);
1888 /* Perform relocations with addend if there are any: */
1889 if ((rela = ef->rela) != NULL) {
1890 relalim = (const Elf_Rela *)
1891 ((const char *)ef->rela + ef->relasize);
1892 while (rela < relalim) {
1893 elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1894 ELF_RELOC_RELA, elf_lookup);
1901 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1903 elf_file_t ef = (elf_file_t)lf;
1905 *symtab = ef->ddbsymtab;
1907 if (*symtab == NULL)
1910 return (ef->ddbsymcnt);
1914 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1916 elf_file_t ef = (elf_file_t)lf;
1918 *strtab = ef->ddbstrtab;
1920 if (*strtab == NULL)
1923 return (ef->ddbstrcnt);
1926 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) || defined(__powerpc__)
1928 * Use this lookup routine when performing relocations early during boot.
1929 * The generic lookup routine depends on kobj, which is not initialized
1933 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused,
1937 const Elf_Sym *symp;
1940 ef = (elf_file_t)lf;
1941 symp = ef->symtab + symidx;
1942 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) {
1943 val = (caddr_t)ef->address + symp->st_value;
1944 *res = ((Elf_Addr (*)(void))val)();
1951 link_elf_ireloc(caddr_t kmdp)
1953 struct elf_file eff;
1959 bzero_early(ef, sizeof(*ef));
1962 ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
1964 #ifdef RELOCATABLE_KERNEL
1965 ef->address = (caddr_t) (__startkernel - KERNBASE);
1971 link_elf_preload_parse_symbols(ef);
1972 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);