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
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/kernel.h>
36 #include <sys/malloc.h>
40 #include <sys/mutex.h>
41 #include <sys/mount.h>
44 #include <sys/namei.h>
45 #include <sys/fcntl.h>
46 #include <sys/vnode.h>
47 #include <sys/linker.h>
48 #include <sys/sysctl.h>
49 #include <sys/tslog.h>
51 #include <machine/elf.h>
55 #include <security/mac/mac_framework.h>
58 #include <vm/vm_param.h>
60 #include <vm/vm_object.h>
61 #include <vm/vm_kern.h>
62 #include <vm/vm_extern.h>
65 #include <vm/vm_map.h>
67 #include <sys/link_elf.h>
69 #include "linker_if.h"
73 typedef struct elf_file {
74 struct linker_file lf; /* Common fields */
75 int preloaded; /* Was file pre-loaded */
76 caddr_t address; /* Relocation address */
78 vm_object_t object; /* VM object to hold file pages */
80 Elf_Dyn *dynamic; /* Symbol table etc. */
81 Elf_Hashelt nbuckets; /* DT_HASH info */
83 const Elf_Hashelt *buckets;
84 const Elf_Hashelt *chains;
86 caddr_t strtab; /* DT_STRTAB */
87 int strsz; /* DT_STRSZ */
88 const Elf_Sym *symtab; /* DT_SYMTAB */
89 Elf_Addr *got; /* DT_PLTGOT */
90 const Elf_Rel *pltrel; /* DT_JMPREL */
91 int pltrelsize; /* DT_PLTRELSZ */
92 const Elf_Rela *pltrela; /* DT_JMPREL */
93 int pltrelasize; /* DT_PLTRELSZ */
94 const Elf_Rel *rel; /* DT_REL */
95 int relsize; /* DT_RELSZ */
96 const Elf_Rela *rela; /* DT_RELA */
97 int relasize; /* DT_RELASZ */
99 const Elf_Sym *ddbsymtab; /* The symbol table we are using */
100 long ddbsymcnt; /* Number of symbols */
101 caddr_t ddbstrtab; /* String table */
102 long ddbstrcnt; /* number of bytes in string table */
103 caddr_t symbase; /* malloc'ed symbold base */
104 caddr_t strbase; /* malloc'ed string base */
105 caddr_t ctftab; /* CTF table */
106 long ctfcnt; /* number of bytes in CTF table */
107 caddr_t ctfoff; /* CTF offset table */
108 caddr_t typoff; /* Type offset table */
109 long typlen; /* Number of type entries. */
110 Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */
111 Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */
112 Elf_Addr pcpu_base; /* Relocated pcpu set address. */
114 Elf_Addr vnet_start; /* Pre-relocation vnet set start. */
115 Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */
116 Elf_Addr vnet_base; /* Relocated vnet set address. */
119 struct link_map gdb; /* hooks for gdb */
127 TAILQ_ENTRY(elf_set) es_link;
130 TAILQ_HEAD(elf_set_head, elf_set);
132 #include <kern/kern_ctf.c>
134 static int link_elf_link_common_finish(linker_file_t);
135 static int link_elf_link_preload(linker_class_t cls,
136 const char *, linker_file_t *);
137 static int link_elf_link_preload_finish(linker_file_t);
138 static int link_elf_load_file(linker_class_t, const char *,
140 static int link_elf_lookup_symbol(linker_file_t, const char *,
142 static int link_elf_lookup_debug_symbol(linker_file_t, const char *,
144 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
146 static int link_elf_debug_symbol_values(linker_file_t, c_linker_sym_t,
148 static int link_elf_search_symbol(linker_file_t, caddr_t,
149 c_linker_sym_t *, long *);
151 static void link_elf_unload_file(linker_file_t);
152 static void link_elf_unload_preload(linker_file_t);
153 static int link_elf_lookup_set(linker_file_t, const char *,
154 void ***, void ***, int *);
155 static int link_elf_each_function_name(linker_file_t,
156 int (*)(const char *, void *), void *);
157 static int link_elf_each_function_nameval(linker_file_t,
158 linker_function_nameval_callback_t, void *);
159 static void link_elf_reloc_local(linker_file_t);
160 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
161 static long link_elf_strtab_get(linker_file_t, caddr_t *);
163 static void link_elf_propagate_vnets(linker_file_t);
165 static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
167 static kobj_method_t link_elf_methods[] = {
168 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
169 KOBJMETHOD(linker_lookup_debug_symbol, link_elf_lookup_debug_symbol),
170 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
171 KOBJMETHOD(linker_debug_symbol_values, link_elf_debug_symbol_values),
172 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
173 KOBJMETHOD(linker_unload, link_elf_unload_file),
174 KOBJMETHOD(linker_load_file, link_elf_load_file),
175 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
176 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
177 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
178 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
179 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
180 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
181 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
182 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
184 KOBJMETHOD(linker_propagate_vnets, link_elf_propagate_vnets),
189 static struct linker_class link_elf_class = {
190 #if ELF_TARG_CLASS == ELFCLASS32
195 link_elf_methods, sizeof(struct elf_file)
198 static bool link_elf_leak_locals = true;
199 SYSCTL_BOOL(_debug, OID_AUTO, link_elf_leak_locals,
200 CTLFLAG_RWTUN, &link_elf_leak_locals, 0,
201 "Allow local symbols to participate in global module symbol resolution");
203 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase,
204 const void *data, int type, elf_lookup_fn lookup);
206 static int parse_dynamic(elf_file_t);
207 static int relocate_file(elf_file_t);
208 static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup,
209 elf_reloc_fn reloc, bool ifuncs);
210 static int link_elf_preload_parse_symbols(elf_file_t);
212 static struct elf_set_head set_pcpu_list;
214 static struct elf_set_head set_vnet_list;
218 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
220 struct elf_set *set, *iter;
222 set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
223 set->es_start = start;
227 TAILQ_FOREACH(iter, list, es_link) {
228 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
229 (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
230 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
231 (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
232 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
234 if (iter->es_start > set->es_start) {
235 TAILQ_INSERT_BEFORE(iter, set, es_link);
241 TAILQ_INSERT_TAIL(list, set, es_link);
245 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
249 TAILQ_FOREACH(set, list, es_link) {
250 if (addr < set->es_start)
252 if (addr < set->es_stop) {
253 *start = set->es_start;
254 *base = set->es_base;
263 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
267 TAILQ_FOREACH(set, list, es_link) {
268 if (start < set->es_start)
270 if (start == set->es_start) {
271 TAILQ_REMOVE(list, set, es_link);
276 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
281 static void r_debug_state(struct r_debug *, struct link_map *);
284 * A list of loaded modules for GDB to use for loading symbols.
286 struct r_debug r_debug;
288 #define GDB_STATE(s) do { \
289 r_debug.r_state = s; r_debug_state(NULL, NULL); \
293 * Function for the debugger to set a breakpoint on to gain control.
296 r_debug_state(struct r_debug *dummy_one __unused,
297 struct link_map *dummy_two __unused)
302 link_elf_add_gdb(struct link_map *l)
304 struct link_map *prev;
308 if (r_debug.r_map == NULL) {
313 /* Append to list. */
314 for (prev = r_debug.r_map;
315 prev->l_next != NULL;
324 link_elf_delete_gdb(struct link_map *l)
326 if (l->l_prev == NULL) {
328 if ((r_debug.r_map = l->l_next) != NULL)
329 l->l_next->l_prev = NULL;
331 /* Remove any but first. */
332 if ((l->l_prev->l_next = l->l_next) != NULL)
333 l->l_next->l_prev = l->l_prev;
339 * The kernel symbol table starts here.
341 extern struct _dynamic _DYNAMIC;
344 link_elf_error(const char *filename, const char *s)
346 if (filename == NULL)
347 printf("kldload: %s\n", s);
349 printf("kldload: %s: %s\n", filename, s);
353 link_elf_invoke_ctors(caddr_t addr, size_t size)
358 if (addr == NULL || size == 0)
360 cnt = size / sizeof(*ctor);
362 for (i = 0; i < cnt; i++) {
369 * Actions performed after linking/loading both the preloaded kernel and any
370 * modules; whether preloaded or dynamicly loaded.
373 link_elf_link_common_finish(linker_file_t lf)
376 elf_file_t ef = (elf_file_t)lf;
381 /* Notify MD code that a module is being loaded. */
382 error = elf_cpu_load_file(lf);
388 ef->gdb.l_addr = lf->address;
389 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
390 strcpy(newfilename, lf->filename);
391 ef->gdb.l_name = newfilename;
392 ef->gdb.l_ld = ef->dynamic;
393 link_elf_add_gdb(&ef->gdb);
394 GDB_STATE(RT_CONSISTENT);
398 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
402 #ifdef RELOCATABLE_KERNEL
404 * __startkernel and __endkernel are symbols set up as relocation canaries.
406 * They are defined in locore to reference linker script symbols at the
407 * beginning and end of the LOAD area. This has the desired side effect of
408 * giving us variables that have relative relocations pointing at them, so
409 * relocation of the kernel object will cause the variables to be updated
410 * automatically by the runtime linker when we initialize.
412 * There are two main reasons to relocate the kernel:
413 * 1) If the loader needed to load the kernel at an alternate load address.
414 * 2) If the kernel is switching address spaces on machines like POWER9
415 * under Radix where the high bits of the effective address are used to
416 * differentiate between hypervisor, host, guest, and problem state.
418 extern vm_offset_t __startkernel, __endkernel;
421 static unsigned long kern_relbase = KERNBASE;
423 SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD,
424 SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address");
425 SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD,
426 &kern_relbase, 0, "Kernel relocated base address");
429 link_elf_init(void* arg)
432 Elf_Addr *ctors_addrp;
433 Elf_Size *ctors_sizep;
434 caddr_t modptr, baseptr, sizeptr;
438 linker_add_class(&link_elf_class);
440 dp = (Elf_Dyn *)&_DYNAMIC;
442 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
444 modptr = preload_search_by_type("elf kernel");
445 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
448 linker_kernel_file = linker_make_file(modname, &link_elf_class);
449 if (linker_kernel_file == NULL)
450 panic("%s: Can't create linker structures for kernel",
453 ef = (elf_file_t) linker_kernel_file;
455 #ifdef RELOCATABLE_KERNEL
456 /* Compute relative displacement */
457 ef->address = (caddr_t) (__startkernel - KERNBASE);
461 #ifdef SPARSE_MAPPING
468 #ifdef RELOCATABLE_KERNEL
469 linker_kernel_file->address = (caddr_t)__startkernel;
470 linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
471 kern_relbase = (unsigned long)__startkernel;
473 linker_kernel_file->address += KERNBASE;
474 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
477 if (modptr != NULL) {
479 baseptr = preload_search_info(modptr, MODINFO_ADDR);
481 linker_kernel_file->address = *(caddr_t *)baseptr;
482 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
484 linker_kernel_file->size = *(size_t *)sizeptr;
485 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
486 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
487 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
488 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
489 if (ctors_addrp != NULL && ctors_sizep != NULL) {
490 linker_kernel_file->ctors_addr = ef->address +
492 linker_kernel_file->ctors_size = *ctors_sizep;
495 (void)link_elf_preload_parse_symbols(ef);
498 r_debug.r_map = NULL;
499 r_debug.r_brk = r_debug_state;
500 r_debug.r_state = RT_CONSISTENT;
503 (void)link_elf_link_common_finish(linker_kernel_file);
504 linker_kernel_file->flags |= LINKER_FILE_LINKED;
505 TAILQ_INIT(&set_pcpu_list);
507 TAILQ_INIT(&set_vnet_list);
508 vnet_save_init((void *)VNET_START, VNET_STOP - VNET_START);
512 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL);
515 link_elf_preload_parse_symbols(elf_file_t ef)
518 caddr_t ssym, esym, base;
524 if (ef->modptr == NULL)
526 pointer = preload_search_info(ef->modptr,
527 MODINFO_METADATA | MODINFOMD_SSYM);
530 ssym = *(caddr_t *)pointer;
531 pointer = preload_search_info(ef->modptr,
532 MODINFO_METADATA | MODINFOMD_ESYM);
535 esym = *(caddr_t *)pointer;
539 symcnt = *(long *)base;
540 base += sizeof(long);
541 symtab = (Elf_Sym *)base;
542 base += roundup(symcnt, sizeof(long));
544 if (base > esym || base < ssym) {
545 printf("Symbols are corrupt!\n");
549 strcnt = *(long *)base;
550 base += sizeof(long);
552 base += roundup(strcnt, sizeof(long));
554 if (base > esym || base < ssym) {
555 printf("Symbols are corrupt!\n");
559 ef->ddbsymtab = symtab;
560 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
561 ef->ddbstrtab = strtab;
562 ef->ddbstrcnt = strcnt;
568 parse_dynamic(elf_file_t ef)
571 int plttype = DT_REL;
573 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
577 /* From src/libexec/rtld-elf/rtld.c */
578 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
579 (ef->address + dp->d_un.d_ptr);
580 ef->nbuckets = hashtab[0];
581 ef->nchains = hashtab[1];
582 ef->buckets = hashtab + 2;
583 ef->chains = ef->buckets + ef->nbuckets;
587 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
590 ef->strsz = dp->d_un.d_val;
593 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
596 if (dp->d_un.d_val != sizeof(Elf_Sym))
600 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
603 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
606 ef->relsize = dp->d_un.d_val;
609 if (dp->d_un.d_val != sizeof(Elf_Rel))
613 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
616 ef->pltrelsize = dp->d_un.d_val;
619 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
622 ef->relasize = dp->d_un.d_val;
625 if (dp->d_un.d_val != sizeof(Elf_Rela))
629 plttype = dp->d_un.d_val;
630 if (plttype != DT_REL && plttype != DT_RELA)
635 dp->d_un.d_ptr = (Elf_Addr)&r_debug;
641 if (plttype == DT_RELA) {
642 ef->pltrela = (const Elf_Rela *)ef->pltrel;
644 ef->pltrelasize = ef->pltrelsize;
648 ef->ddbsymtab = ef->symtab;
649 ef->ddbsymcnt = ef->nchains;
650 ef->ddbstrtab = ef->strtab;
651 ef->ddbstrcnt = ef->strsz;
653 return elf_cpu_parse_dynamic(ef->address, ef->dynamic);
656 #define LS_PADDING 0x90909090
658 parse_dpcpu(elf_file_t ef)
661 #if defined(__i386__)
667 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
668 (void ***)&ef->pcpu_stop, NULL);
669 /* Error just means there is no pcpu set to relocate. */
672 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start;
676 #if defined(__i386__)
677 /* In case we do find __start/stop_set_ symbols double-check. */
679 uprintf("Kernel module '%s' must be recompiled with "
680 "linker script\n", ef->lf.pathname);
684 /* Padding from linker-script correct? */
685 pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad));
686 if (pad != LS_PADDING) {
687 uprintf("Kernel module '%s' must be recompiled with "
688 "linker script, invalid padding %#04x (%#04x)\n",
689 ef->lf.pathname, pad, LS_PADDING);
692 /* If we only have valid padding, nothing to do. */
697 * Allocate space in the primary pcpu area. Copy in our
698 * initialization from the data section and then initialize
699 * all per-cpu storage from that.
701 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size);
702 if (ef->pcpu_base == 0) {
703 printf("%s: pcpu module space is out of space; "
704 "cannot allocate %d for %s\n",
705 __func__, size, ef->lf.pathname);
708 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size);
709 dpcpu_copy((void *)ef->pcpu_base, size);
710 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
718 parse_vnet(elf_file_t ef)
721 #if defined(__i386__)
728 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
729 (void ***)&ef->vnet_stop, NULL);
730 /* Error just means there is no vnet data set to relocate. */
733 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
737 #if defined(__i386__)
738 /* In case we do find __start/stop_set_ symbols double-check. */
740 uprintf("Kernel module '%s' must be recompiled with "
741 "linker script\n", ef->lf.pathname);
745 /* Padding from linker-script correct? */
746 pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad));
747 if (pad != LS_PADDING) {
748 uprintf("Kernel module '%s' must be recompiled with "
749 "linker script, invalid padding %#04x (%#04x)\n",
750 ef->lf.pathname, pad, LS_PADDING);
753 /* If we only have valid padding, nothing to do. */
758 * Allocate space in the primary vnet area. Copy in our
759 * initialization from the data section and then initialize
760 * all per-vnet storage from that.
762 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size);
763 if (ef->vnet_base == 0) {
764 printf("%s: vnet module space is out of space; "
765 "cannot allocate %d for %s\n",
766 __func__, size, ef->lf.pathname);
769 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size);
770 vnet_save_init((void *)ef->vnet_base, size);
771 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
780 * Apply the specified protection to the loadable segments of a preloaded linker
784 preload_protect(elf_file_t ef, vm_prot_t prot)
786 #if defined(__aarch64__) || defined(__amd64__)
788 Elf_Phdr *phdr, *phlimit;
793 hdr = (Elf_Ehdr *)ef->address;
794 phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff);
795 phlimit = phdr + hdr->e_phnum;
796 for (; phdr < phlimit; phdr++) {
797 if (phdr->p_type != PT_LOAD)
800 nprot = prot | VM_PROT_READ;
801 if ((phdr->p_flags & PF_W) != 0)
802 nprot |= VM_PROT_WRITE;
803 if ((phdr->p_flags & PF_X) != 0)
804 nprot |= VM_PROT_EXECUTE;
805 error = pmap_change_prot((vm_offset_t)ef->address +
806 phdr->p_vaddr, round_page(phdr->p_memsz), nprot);
818 * Locate the ARM exception/unwind table info for DDB and stack(9) use by
819 * searching for the section header that describes it. There may be no unwind
820 * info, for example in a module containing only data.
823 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr)
827 for (i = 0; i < nhdr; i++) {
828 if (shdr[i].sh_type == SHT_ARM_EXIDX) {
829 lf->exidx_addr = shdr[i].sh_addr + lf->address;
830 lf->exidx_size = shdr[i].sh_size;
837 * Locate the section headers metadata in a preloaded module, then use it to
838 * locate the exception/unwind table in the module. The size of the metadata
839 * block is stored in a uint32 word immediately before the data itself, and a
840 * comment in preload_search_info() says it is safe to rely on that.
843 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr)
849 modinfo = (uint32_t *)preload_search_info(modptr,
850 MODINFO_METADATA | MODINFOMD_SHDR);
851 if (modinfo != NULL) {
852 shdr = (Elf_Shdr *)modinfo;
853 nhdr = modinfo[-1] / sizeof(Elf_Shdr);
854 link_elf_locate_exidx(lf, shdr, nhdr);
861 link_elf_link_preload(linker_class_t cls, const char *filename,
862 linker_file_t *result)
864 Elf_Addr *ctors_addrp;
865 Elf_Size *ctors_sizep;
866 caddr_t modptr, baseptr, sizeptr, dynptr;
873 /* Look to see if we have the file preloaded */
874 modptr = preload_search_by_name(filename);
878 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
879 baseptr = preload_search_info(modptr, MODINFO_ADDR);
880 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
881 dynptr = preload_search_info(modptr,
882 MODINFO_METADATA | MODINFOMD_DYNAMIC);
884 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
885 strcmp(type, "elf module") != 0))
887 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
890 lf = linker_make_file(filename, &link_elf_class);
894 ef = (elf_file_t) lf;
897 ef->address = *(caddr_t *)baseptr;
898 #ifdef SPARSE_MAPPING
901 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
902 ef->dynamic = (Elf_Dyn *)dp;
903 lf->address = ef->address;
904 lf->size = *(size_t *)sizeptr;
906 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
907 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
908 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
909 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
910 if (ctors_addrp != NULL && ctors_sizep != NULL) {
911 lf->ctors_addr = ef->address + *ctors_addrp;
912 lf->ctors_size = *ctors_sizep;
916 link_elf_locate_exidx_preload(lf, modptr);
919 error = parse_dynamic(ef);
921 error = parse_dpcpu(ef);
924 error = parse_vnet(ef);
927 error = preload_protect(ef, VM_PROT_ALL);
929 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
932 link_elf_reloc_local(lf);
938 link_elf_link_preload_finish(linker_file_t lf)
943 ef = (elf_file_t) lf;
944 error = relocate_file(ef);
946 error = preload_protect(ef, VM_PROT_NONE);
949 (void)link_elf_preload_parse_symbols(ef);
951 return (link_elf_link_common_finish(lf));
955 link_elf_load_file(linker_class_t cls, const char* filename,
956 linker_file_t* result)
959 struct thread* td = curthread; /* XXX */
961 caddr_t firstpage, segbase;
965 Elf_Phdr *segs[MAXSEGS];
971 Elf_Addr base_vlimit;
989 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename);
991 error = vn_open(&nd, &flags, 0, NULL);
995 if (nd.ni_vp->v_type != VREG) {
1001 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
1009 * Read the elf header from the file.
1011 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
1012 hdr = (Elf_Ehdr *)firstpage;
1013 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
1014 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1016 nbytes = PAGE_SIZE - resid;
1020 if (!IS_ELF(*hdr)) {
1025 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
1026 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
1027 link_elf_error(filename, "Unsupported file layout");
1031 if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
1032 hdr->e_version != EV_CURRENT) {
1033 link_elf_error(filename, "Unsupported file version");
1037 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
1041 if (hdr->e_machine != ELF_TARG_MACH) {
1042 link_elf_error(filename, "Unsupported machine");
1048 * We rely on the program header being in the first page.
1049 * This is not strictly required by the ABI specification, but
1050 * it seems to always true in practice. And, it simplifies
1051 * things considerably.
1053 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
1054 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
1055 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
1056 link_elf_error(filename, "Unreadable program headers");
1059 * Scan the program header entries, and save key information.
1061 * We rely on there being exactly two load segments, text and data,
1064 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
1065 phlimit = phdr + hdr->e_phnum;
1068 while (phdr < phlimit) {
1069 switch (phdr->p_type) {
1071 if (nsegs == MAXSEGS) {
1072 link_elf_error(filename, "Too many sections");
1077 * XXX: We just trust they come in right order ??
1094 if (phdyn == NULL) {
1095 link_elf_error(filename, "Object is not dynamically-linked");
1100 link_elf_error(filename, "No sections");
1106 * Allocate the entire address space of the object, to stake
1107 * out our contiguous region, and to establish the base
1108 * address for relocation.
1110 base_vaddr = trunc_page(segs[0]->p_vaddr);
1111 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
1112 segs[nsegs - 1]->p_memsz);
1113 mapsize = base_vlimit - base_vaddr;
1115 lf = linker_make_file(filename, &link_elf_class);
1121 ef = (elf_file_t) lf;
1122 #ifdef SPARSE_MAPPING
1123 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, mapsize, VM_PROT_ALL,
1124 0, thread0.td_ucred);
1125 if (ef->object == NULL) {
1130 mapbase = (caddr_t)KERNBASE;
1132 mapbase = (caddr_t)vm_map_min(kernel_map);
1135 * Mapping protections are downgraded after relocation processing.
1137 error = vm_map_find(kernel_map, ef->object, 0,
1138 (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE,
1139 VM_PROT_ALL, VM_PROT_ALL, 0);
1141 vm_object_deallocate(ef->object);
1146 mapbase = malloc_exec(mapsize, M_LINKER, M_WAITOK);
1148 ef->address = mapbase;
1151 * Read the text and data sections and zero the bss.
1153 for (i = 0; i < nsegs; i++) {
1154 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1156 #ifdef SPARSE_MAPPING
1158 * Consecutive segments may have different mapping permissions,
1159 * so be strict and verify that their mappings do not overlap.
1161 if (((vm_offset_t)segbase & PAGE_MASK) != 0) {
1166 error = vm_map_wire(kernel_map,
1167 (vm_offset_t)segbase,
1168 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1169 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
1170 if (error != KERN_SUCCESS) {
1176 error = vn_rdwr(UIO_READ, nd.ni_vp,
1177 segbase, segs[i]->p_filesz, segs[i]->p_offset,
1178 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1182 bzero(segbase + segs[i]->p_filesz,
1183 segs[i]->p_memsz - segs[i]->p_filesz);
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;
1441 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \
1442 for ((iter) = (tbl); (iter) != NULL && \
1443 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \
1444 if ((symbol_type(ef, (iter)->r_info) == \
1446 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \
1448 if (reloc(&ef->lf, (Elf_Addr)ef->address, \
1449 (iter), (type), lookup)) { \
1450 symname = symbol_name(ef, (iter)->r_info); \
1451 printf("link_elf: symbol %s undefined\n", \
1458 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL);
1459 TSENTER2("ef->rela");
1460 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA);
1461 TSEXIT2("ef->rela");
1462 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL);
1463 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA);
1472 relocate_file(elf_file_t ef)
1476 error = relocate_file1(ef, elf_lookup, elf_reloc, false);
1478 error = relocate_file1(ef, elf_lookup, elf_reloc, true);
1483 * SysV hash function for symbol table lookup. It is specified by the
1487 elf_hash(const char *name)
1489 const unsigned char *p = (const unsigned char *)name;
1492 while (*p != '\0') {
1493 h = (h << 4) + *p++;
1494 h ^= (h >> 24) & 0xf0;
1496 return (h & 0x0fffffff);
1500 link_elf_lookup_symbol1(linker_file_t lf, const char *name, c_linker_sym_t *sym,
1503 elf_file_t ef = (elf_file_t) lf;
1504 unsigned long symnum;
1505 const Elf_Sym* symp;
1509 /* If we don't have a hash, bail. */
1510 if (ef->buckets == NULL || ef->nbuckets == 0) {
1511 printf("link_elf_lookup_symbol: missing symbol hash table\n");
1515 /* First, search hashed global symbols */
1516 hash = elf_hash(name);
1517 symnum = ef->buckets[hash % ef->nbuckets];
1519 while (symnum != STN_UNDEF) {
1520 if (symnum >= ef->nchains) {
1521 printf("%s: corrupt symbol table\n", __func__);
1525 symp = ef->symtab + symnum;
1526 if (symp->st_name == 0) {
1527 printf("%s: corrupt symbol table\n", __func__);
1531 strp = ef->strtab + symp->st_name;
1533 if (strcmp(name, strp) == 0) {
1534 if (symp->st_shndx != SHN_UNDEF ||
1535 (symp->st_value != 0 &&
1536 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1537 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1539 ELF_ST_BIND(symp->st_info) != STB_LOCAL) {
1540 *sym = (c_linker_sym_t) symp;
1547 symnum = ef->chains[symnum];
1554 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1556 if (link_elf_leak_locals)
1557 return (link_elf_lookup_debug_symbol(lf, name, sym));
1558 return (link_elf_lookup_symbol1(lf, name, sym, false));
1562 link_elf_lookup_debug_symbol(linker_file_t lf, const char *name,
1563 c_linker_sym_t *sym)
1565 elf_file_t ef = (elf_file_t)lf;
1566 const Elf_Sym* symp;
1570 if (link_elf_lookup_symbol1(lf, name, sym, true) == 0)
1573 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1574 strp = ef->ddbstrtab + symp->st_name;
1575 if (strcmp(name, strp) == 0) {
1576 if (symp->st_shndx != SHN_UNDEF ||
1577 (symp->st_value != 0 &&
1578 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1579 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1580 *sym = (c_linker_sym_t) symp;
1591 link_elf_symbol_values1(linker_file_t lf, c_linker_sym_t sym,
1592 linker_symval_t *symval, bool see_local)
1598 ef = (elf_file_t)lf;
1599 es = (const Elf_Sym *)sym;
1600 if (es >= ef->symtab && es < ef->symtab + ef->nchains) {
1601 if (!see_local && ELF_ST_BIND(es->st_info) == STB_LOCAL)
1603 symval->name = ef->strtab + es->st_name;
1604 val = (caddr_t)ef->address + es->st_value;
1605 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1606 val = ((caddr_t (*)(void))val)();
1607 symval->value = val;
1608 symval->size = es->st_size;
1615 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1616 linker_symval_t *symval)
1618 if (link_elf_leak_locals)
1619 return (link_elf_debug_symbol_values(lf, sym, symval));
1620 return (link_elf_symbol_values1(lf, sym, symval, false));
1624 link_elf_debug_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1625 linker_symval_t *symval)
1627 elf_file_t ef = (elf_file_t)lf;
1628 const Elf_Sym *es = (const Elf_Sym *)sym;
1631 if (link_elf_symbol_values1(lf, sym, symval, true) == 0)
1633 if (ef->symtab == ef->ddbsymtab)
1636 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1637 symval->name = ef->ddbstrtab + es->st_name;
1638 val = (caddr_t)ef->address + es->st_value;
1639 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1640 val = ((caddr_t (*)(void))val)();
1641 symval->value = val;
1642 symval->size = es->st_size;
1649 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1650 c_linker_sym_t *sym, long *diffp)
1652 elf_file_t ef = (elf_file_t)lf;
1653 u_long off = (uintptr_t)(void *)value;
1657 const Elf_Sym *best = NULL;
1660 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1661 if (es->st_name == 0)
1663 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1664 if (off >= st_value) {
1665 if (off - st_value < diff) {
1666 diff = off - st_value;
1670 } else if (off - st_value == diff) {
1679 *sym = (c_linker_sym_t) best;
1685 * Look up a linker set on an ELF system.
1688 link_elf_lookup_set(linker_file_t lf, const char *name,
1689 void ***startp, void ***stopp, int *countp)
1692 linker_symval_t symval;
1694 void **start, **stop;
1695 int len, error = 0, count;
1697 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1698 setsym = malloc(len, M_LINKER, M_WAITOK);
1700 /* get address of first entry */
1701 snprintf(setsym, len, "%s%s", "__start_set_", name);
1702 error = link_elf_lookup_symbol(lf, setsym, &sym);
1705 link_elf_symbol_values(lf, sym, &symval);
1706 if (symval.value == 0) {
1710 start = (void **)symval.value;
1712 /* get address of last entry */
1713 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1714 error = link_elf_lookup_symbol(lf, setsym, &sym);
1717 link_elf_symbol_values(lf, sym, &symval);
1718 if (symval.value == 0) {
1722 stop = (void **)symval.value;
1724 /* and the number of entries */
1725 count = stop - start;
1736 free(setsym, M_LINKER);
1741 link_elf_each_function_name(linker_file_t file,
1742 int (*callback)(const char *, void *), void *opaque)
1744 elf_file_t ef = (elf_file_t)file;
1745 const Elf_Sym *symp;
1748 /* Exhaustive search */
1749 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1750 if (symp->st_value != 0 &&
1751 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1752 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1753 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1762 link_elf_each_function_nameval(linker_file_t file,
1763 linker_function_nameval_callback_t callback, void *opaque)
1765 linker_symval_t symval;
1766 elf_file_t ef = (elf_file_t)file;
1767 const Elf_Sym *symp;
1770 /* Exhaustive search */
1771 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1772 if (symp->st_value != 0 &&
1773 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1774 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1775 error = link_elf_debug_symbol_values(file,
1776 (c_linker_sym_t) symp, &symval);
1778 error = callback(file, i, &symval, opaque);
1787 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1789 elf_file_t ef = (elf_file_t)lf;
1791 if (symidx >= ef->nchains)
1793 return (ef->symtab + symidx);
1797 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1799 elf_file_t ef = (elf_file_t)lf;
1802 if (symidx >= ef->nchains)
1804 sym = ef->symtab + symidx;
1805 return (ef->strtab + sym->st_name);
1809 * Symbol lookup function that can be used when the symbol index is known (ie
1810 * in relocations). It uses the symbol index instead of doing a fully fledged
1811 * hash table based lookup when such is valid. For example for local symbols.
1812 * This is not only more efficient, it's also more correct. It's not always
1813 * the case that the symbol can be found through the hash table.
1816 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1818 elf_file_t ef = (elf_file_t)lf;
1821 Elf_Addr addr, start, base;
1823 /* Don't even try to lookup the symbol if the index is bogus. */
1824 if (symidx >= ef->nchains) {
1829 sym = ef->symtab + symidx;
1832 * Don't do a full lookup when the symbol is local. It may even
1833 * fail because it may not be found through the hash table.
1835 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1836 /* Force lookup failure when we have an insanity. */
1837 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1841 *res = ((Elf_Addr)ef->address + sym->st_value);
1846 * XXX we can avoid doing a hash table based lookup for global
1847 * symbols as well. This however is not always valid, so we'll
1848 * just do it the hard way for now. Performance tweaks can
1852 symbol = ef->strtab + sym->st_name;
1854 /* Force a lookup failure if the symbol name is bogus. */
1860 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1861 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1866 if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1867 addr = addr - start + base;
1869 else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1870 addr = addr - start + base;
1877 link_elf_reloc_local(linker_file_t lf)
1879 const Elf_Rel *rellim;
1881 const Elf_Rela *relalim;
1882 const Elf_Rela *rela;
1883 elf_file_t ef = (elf_file_t)lf;
1885 /* Perform relocations without addend if there are any: */
1886 if ((rel = ef->rel) != NULL) {
1887 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1888 while (rel < rellim) {
1889 elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1890 ELF_RELOC_REL, elf_lookup);
1895 /* Perform relocations with addend if there are any: */
1896 if ((rela = ef->rela) != NULL) {
1897 relalim = (const Elf_Rela *)
1898 ((const char *)ef->rela + ef->relasize);
1899 while (rela < relalim) {
1900 elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1901 ELF_RELOC_RELA, elf_lookup);
1908 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1910 elf_file_t ef = (elf_file_t)lf;
1912 *symtab = ef->ddbsymtab;
1914 if (*symtab == NULL)
1917 return (ef->ddbsymcnt);
1921 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1923 elf_file_t ef = (elf_file_t)lf;
1925 *strtab = ef->ddbstrtab;
1927 if (*strtab == NULL)
1930 return (ef->ddbstrcnt);
1935 link_elf_propagate_vnets(linker_file_t lf)
1937 elf_file_t ef = (elf_file_t)lf;
1940 if (ef->vnet_base != 0) {
1941 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
1942 vnet_data_copy((void *)ef->vnet_base, size);
1947 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) || defined(__powerpc__)
1949 * Use this lookup routine when performing relocations early during boot.
1950 * The generic lookup routine depends on kobj, which is not initialized
1954 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused,
1958 const Elf_Sym *symp;
1961 ef = (elf_file_t)lf;
1962 symp = ef->symtab + symidx;
1963 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) {
1964 val = (caddr_t)ef->address + symp->st_value;
1965 *res = ((Elf_Addr (*)(void))val)();
1972 link_elf_ireloc(caddr_t kmdp)
1974 struct elf_file eff;
1980 bzero_early(ef, sizeof(*ef));
1983 ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
1985 #ifdef RELOCATABLE_KERNEL
1986 ef->address = (caddr_t) (__startkernel - KERNBASE);
1992 link_elf_preload_parse_symbols(ef);
1993 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true);
1997 #if defined(__aarch64__) || defined(__amd64__)
1999 link_elf_late_ireloc(void)
2003 KASSERT(linker_kernel_file != NULL,
2004 ("link_elf_late_ireloc: No kernel linker file found"));
2005 ef = (elf_file_t)linker_kernel_file;
2007 relocate_file1(ef, elf_lookup_ifunc, elf_reloc_late, true);