2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 1998-2000 Doug Rabson
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
35 #include <sys/param.h>
36 #include <sys/systm.h>
40 #include <sys/kernel.h>
42 #include <sys/malloc.h>
46 #include <sys/mutex.h>
47 #include <sys/mount.h>
50 #include <sys/namei.h>
51 #include <sys/fcntl.h>
52 #include <sys/vnode.h>
53 #include <sys/linker.h>
54 #include <sys/sysctl.h>
56 #include <machine/elf.h>
60 #include <security/mac/mac_framework.h>
63 #include <vm/vm_param.h>
65 #include <vm/vm_object.h>
66 #include <vm/vm_kern.h>
67 #include <vm/vm_extern.h>
70 #include <vm/vm_map.h>
72 #include <sys/link_elf.h>
74 #include "linker_if.h"
78 typedef struct elf_file {
79 struct linker_file lf; /* Common fields */
80 int preloaded; /* Was file pre-loaded */
81 caddr_t address; /* Relocation address */
83 vm_object_t object; /* VM object to hold file pages */
85 Elf_Dyn *dynamic; /* Symbol table etc. */
86 Elf_Hashelt nbuckets; /* DT_HASH info */
88 const Elf_Hashelt *buckets;
89 const Elf_Hashelt *chains;
91 caddr_t strtab; /* DT_STRTAB */
92 int strsz; /* DT_STRSZ */
93 const Elf_Sym *symtab; /* DT_SYMTAB */
94 Elf_Addr *got; /* DT_PLTGOT */
95 const Elf_Rel *pltrel; /* DT_JMPREL */
96 int pltrelsize; /* DT_PLTRELSZ */
97 const Elf_Rela *pltrela; /* DT_JMPREL */
98 int pltrelasize; /* DT_PLTRELSZ */
99 const Elf_Rel *rel; /* DT_REL */
100 int relsize; /* DT_RELSZ */
101 const Elf_Rela *rela; /* DT_RELA */
102 int relasize; /* DT_RELASZ */
104 const Elf_Sym *ddbsymtab; /* The symbol table we are using */
105 long ddbsymcnt; /* Number of symbols */
106 caddr_t ddbstrtab; /* String table */
107 long ddbstrcnt; /* number of bytes in string table */
108 caddr_t symbase; /* malloc'ed symbold base */
109 caddr_t strbase; /* malloc'ed string base */
110 caddr_t ctftab; /* CTF table */
111 long ctfcnt; /* number of bytes in CTF table */
112 caddr_t ctfoff; /* CTF offset table */
113 caddr_t typoff; /* Type offset table */
114 long typlen; /* Number of type entries. */
115 Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */
116 Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */
117 Elf_Addr pcpu_base; /* Relocated pcpu set address. */
119 Elf_Addr vnet_start; /* Pre-relocation vnet set start. */
120 Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */
121 Elf_Addr vnet_base; /* Relocated vnet set address. */
124 struct link_map gdb; /* hooks for gdb */
132 TAILQ_ENTRY(elf_set) es_link;
135 TAILQ_HEAD(elf_set_head, elf_set);
137 #include <kern/kern_ctf.c>
139 static int link_elf_link_common_finish(linker_file_t);
140 static int link_elf_link_preload(linker_class_t cls,
141 const char *, linker_file_t *);
142 static int link_elf_link_preload_finish(linker_file_t);
143 static int link_elf_load_file(linker_class_t, const char *,
145 static int link_elf_lookup_symbol(linker_file_t, const char *,
147 static int link_elf_lookup_debug_symbol(linker_file_t, const char *,
149 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
151 static int link_elf_debug_symbol_values(linker_file_t, c_linker_sym_t,
153 static int link_elf_search_symbol(linker_file_t, caddr_t,
154 c_linker_sym_t *, long *);
156 static void link_elf_unload_file(linker_file_t);
157 static void link_elf_unload_preload(linker_file_t);
158 static int link_elf_lookup_set(linker_file_t, const char *,
159 void ***, void ***, int *);
160 static int link_elf_each_function_name(linker_file_t,
161 int (*)(const char *, void *), void *);
162 static int link_elf_each_function_nameval(linker_file_t,
163 linker_function_nameval_callback_t, void *);
164 static void link_elf_reloc_local(linker_file_t);
165 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
166 static long link_elf_strtab_get(linker_file_t, caddr_t *);
167 static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
169 static kobj_method_t link_elf_methods[] = {
170 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
171 KOBJMETHOD(linker_lookup_debug_symbol, link_elf_lookup_debug_symbol),
172 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
173 KOBJMETHOD(linker_debug_symbol_values, link_elf_debug_symbol_values),
174 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
175 KOBJMETHOD(linker_unload, link_elf_unload_file),
176 KOBJMETHOD(linker_load_file, link_elf_load_file),
177 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
178 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
179 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
180 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
181 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
182 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
183 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
184 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
188 static struct linker_class link_elf_class = {
189 #if ELF_TARG_CLASS == ELFCLASS32
194 link_elf_methods, sizeof(struct elf_file)
197 static bool link_elf_leak_locals = true;
198 SYSCTL_BOOL(_debug, OID_AUTO, link_elf_leak_locals,
199 CTLFLAG_RWTUN, &link_elf_leak_locals, 0,
200 "Allow local symbols to participate in global module symbol resolution");
202 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase,
203 const void *data, int type, elf_lookup_fn lookup);
205 static int parse_dynamic(elf_file_t);
206 static int relocate_file(elf_file_t);
207 static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup,
208 elf_reloc_fn reloc, bool ifuncs);
209 static int link_elf_preload_parse_symbols(elf_file_t);
211 static struct elf_set_head set_pcpu_list;
213 static struct elf_set_head set_vnet_list;
217 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
219 struct elf_set *set, *iter;
221 set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
222 set->es_start = start;
226 TAILQ_FOREACH(iter, list, es_link) {
227 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
228 (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
229 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
230 (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
231 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
233 if (iter->es_start > set->es_start) {
234 TAILQ_INSERT_BEFORE(iter, set, es_link);
240 TAILQ_INSERT_TAIL(list, set, es_link);
244 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
248 TAILQ_FOREACH(set, list, es_link) {
249 if (addr < set->es_start)
251 if (addr < set->es_stop) {
252 *start = set->es_start;
253 *base = set->es_base;
262 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
266 TAILQ_FOREACH(set, list, es_link) {
267 if (start < set->es_start)
269 if (start == set->es_start) {
270 TAILQ_REMOVE(list, set, es_link);
275 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
280 static void r_debug_state(struct r_debug *, struct link_map *);
283 * A list of loaded modules for GDB to use for loading symbols.
285 struct r_debug r_debug;
287 #define GDB_STATE(s) do { \
288 r_debug.r_state = s; r_debug_state(NULL, NULL); \
292 * Function for the debugger to set a breakpoint on to gain control.
295 r_debug_state(struct r_debug *dummy_one __unused,
296 struct link_map *dummy_two __unused)
301 link_elf_add_gdb(struct link_map *l)
303 struct link_map *prev;
307 if (r_debug.r_map == NULL) {
312 /* Append to list. */
313 for (prev = r_debug.r_map;
314 prev->l_next != NULL;
323 link_elf_delete_gdb(struct link_map *l)
325 if (l->l_prev == NULL) {
327 if ((r_debug.r_map = l->l_next) != NULL)
328 l->l_next->l_prev = NULL;
330 /* Remove any but first. */
331 if ((l->l_prev->l_next = l->l_next) != NULL)
332 l->l_next->l_prev = l->l_prev;
338 * The kernel symbol table starts here.
340 extern struct _dynamic _DYNAMIC;
343 link_elf_error(const char *filename, const char *s)
345 if (filename == NULL)
346 printf("kldload: %s\n", s);
348 printf("kldload: %s: %s\n", filename, s);
352 link_elf_invoke_ctors(caddr_t addr, size_t size)
357 if (addr == NULL || size == 0)
359 cnt = size / sizeof(*ctor);
361 for (i = 0; i < cnt; i++) {
368 * Actions performed after linking/loading both the preloaded kernel and any
369 * modules; whether preloaded or dynamicly loaded.
372 link_elf_link_common_finish(linker_file_t lf)
375 elf_file_t ef = (elf_file_t)lf;
380 /* Notify MD code that a module is being loaded. */
381 error = elf_cpu_load_file(lf);
387 ef->gdb.l_addr = lf->address;
388 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
389 strcpy(newfilename, lf->filename);
390 ef->gdb.l_name = newfilename;
391 ef->gdb.l_ld = ef->dynamic;
392 link_elf_add_gdb(&ef->gdb);
393 GDB_STATE(RT_CONSISTENT);
397 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
401 #ifdef RELOCATABLE_KERNEL
403 * __startkernel and __endkernel are symbols set up as relocation canaries.
405 * They are defined in locore to reference linker script symbols at the
406 * beginning and end of the LOAD area. This has the desired side effect of
407 * giving us variables that have relative relocations pointing at them, so
408 * relocation of the kernel object will cause the variables to be updated
409 * automatically by the runtime linker when we initialize.
411 * There are two main reasons to relocate the kernel:
412 * 1) If the loader needed to load the kernel at an alternate load address.
413 * 2) If the kernel is switching address spaces on machines like POWER9
414 * under Radix where the high bits of the effective address are used to
415 * differentiate between hypervisor, host, guest, and problem state.
417 extern vm_offset_t __startkernel, __endkernel;
420 static unsigned long kern_relbase = KERNBASE;
422 SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD,
423 SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address");
424 SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD,
425 &kern_relbase, 0, "Kernel relocated base address");
428 link_elf_init(void* arg)
431 Elf_Addr *ctors_addrp;
432 Elf_Size *ctors_sizep;
433 caddr_t modptr, baseptr, sizeptr;
437 linker_add_class(&link_elf_class);
439 dp = (Elf_Dyn *)&_DYNAMIC;
441 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
443 modptr = preload_search_by_type("elf kernel");
444 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
447 linker_kernel_file = linker_make_file(modname, &link_elf_class);
448 if (linker_kernel_file == NULL)
449 panic("%s: Can't create linker structures for kernel",
452 ef = (elf_file_t) linker_kernel_file;
454 #ifdef RELOCATABLE_KERNEL
455 /* Compute relative displacement */
456 ef->address = (caddr_t) (__startkernel - KERNBASE);
460 #ifdef SPARSE_MAPPING
467 #ifdef RELOCATABLE_KERNEL
468 linker_kernel_file->address = (caddr_t)__startkernel;
469 linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
470 kern_relbase = (unsigned long)__startkernel;
472 linker_kernel_file->address += KERNBASE;
473 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
476 if (modptr != NULL) {
478 baseptr = preload_search_info(modptr, MODINFO_ADDR);
480 linker_kernel_file->address = *(caddr_t *)baseptr;
481 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
483 linker_kernel_file->size = *(size_t *)sizeptr;
484 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
485 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
486 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
487 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
488 if (ctors_addrp != NULL && ctors_sizep != NULL) {
489 linker_kernel_file->ctors_addr = ef->address +
491 linker_kernel_file->ctors_size = *ctors_sizep;
494 (void)link_elf_preload_parse_symbols(ef);
497 r_debug.r_map = NULL;
498 r_debug.r_brk = r_debug_state;
499 r_debug.r_state = RT_CONSISTENT;
502 (void)link_elf_link_common_finish(linker_kernel_file);
503 linker_kernel_file->flags |= LINKER_FILE_LINKED;
504 TAILQ_INIT(&set_pcpu_list);
506 TAILQ_INIT(&set_vnet_list);
510 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL);
513 link_elf_preload_parse_symbols(elf_file_t ef)
516 caddr_t ssym, esym, base;
522 if (ef->modptr == NULL)
524 pointer = preload_search_info(ef->modptr,
525 MODINFO_METADATA | MODINFOMD_SSYM);
528 ssym = *(caddr_t *)pointer;
529 pointer = preload_search_info(ef->modptr,
530 MODINFO_METADATA | MODINFOMD_ESYM);
533 esym = *(caddr_t *)pointer;
537 symcnt = *(long *)base;
538 base += sizeof(long);
539 symtab = (Elf_Sym *)base;
540 base += roundup(symcnt, sizeof(long));
542 if (base > esym || base < ssym) {
543 printf("Symbols are corrupt!\n");
547 strcnt = *(long *)base;
548 base += sizeof(long);
550 base += roundup(strcnt, sizeof(long));
552 if (base > esym || base < ssym) {
553 printf("Symbols are corrupt!\n");
557 ef->ddbsymtab = symtab;
558 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
559 ef->ddbstrtab = strtab;
560 ef->ddbstrcnt = strcnt;
566 parse_dynamic(elf_file_t ef)
569 int plttype = DT_REL;
571 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
575 /* From src/libexec/rtld-elf/rtld.c */
576 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
577 (ef->address + dp->d_un.d_ptr);
578 ef->nbuckets = hashtab[0];
579 ef->nchains = hashtab[1];
580 ef->buckets = hashtab + 2;
581 ef->chains = ef->buckets + ef->nbuckets;
585 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
588 ef->strsz = dp->d_un.d_val;
591 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
594 if (dp->d_un.d_val != sizeof(Elf_Sym))
598 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
601 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
604 ef->relsize = dp->d_un.d_val;
607 if (dp->d_un.d_val != sizeof(Elf_Rel))
611 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
614 ef->pltrelsize = dp->d_un.d_val;
617 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
620 ef->relasize = dp->d_un.d_val;
623 if (dp->d_un.d_val != sizeof(Elf_Rela))
627 plttype = dp->d_un.d_val;
628 if (plttype != DT_REL && plttype != DT_RELA)
633 dp->d_un.d_ptr = (Elf_Addr)&r_debug;
639 if (plttype == DT_RELA) {
640 ef->pltrela = (const Elf_Rela *)ef->pltrel;
642 ef->pltrelasize = ef->pltrelsize;
646 ef->ddbsymtab = ef->symtab;
647 ef->ddbsymcnt = ef->nchains;
648 ef->ddbstrtab = ef->strtab;
649 ef->ddbstrcnt = ef->strsz;
651 return elf_cpu_parse_dynamic(ef->address, ef->dynamic);
654 #define LS_PADDING 0x90909090
656 parse_dpcpu(elf_file_t ef)
659 #if defined(__i386__)
665 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
666 (void ***)&ef->pcpu_stop, NULL);
667 /* Error just means there is no pcpu set to relocate. */
670 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start;
674 #if defined(__i386__)
675 /* In case we do find __start/stop_set_ symbols double-check. */
677 uprintf("Kernel module '%s' must be recompiled with "
678 "linker script\n", ef->lf.pathname);
682 /* Padding from linker-script correct? */
683 pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad));
684 if (pad != LS_PADDING) {
685 uprintf("Kernel module '%s' must be recompiled with "
686 "linker script, invalid padding %#04x (%#04x)\n",
687 ef->lf.pathname, pad, LS_PADDING);
690 /* If we only have valid padding, nothing to do. */
695 * Allocate space in the primary pcpu area. Copy in our
696 * initialization from the data section and then initialize
697 * all per-cpu storage from that.
699 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size);
700 if (ef->pcpu_base == 0) {
701 printf("%s: pcpu module space is out of space; "
702 "cannot allocate %d for %s\n",
703 __func__, size, ef->lf.pathname);
706 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size);
707 dpcpu_copy((void *)ef->pcpu_base, size);
708 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
716 parse_vnet(elf_file_t ef)
719 #if defined(__i386__)
725 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
726 (void ***)&ef->vnet_stop, NULL);
727 /* Error just means there is no vnet data set to relocate. */
730 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
734 #if defined(__i386__)
735 /* In case we do find __start/stop_set_ symbols double-check. */
737 uprintf("Kernel module '%s' must be recompiled with "
738 "linker script\n", ef->lf.pathname);
742 /* Padding from linker-script correct? */
743 pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad));
744 if (pad != LS_PADDING) {
745 uprintf("Kernel module '%s' must be recompiled with "
746 "linker script, invalid padding %#04x (%#04x)\n",
747 ef->lf.pathname, pad, LS_PADDING);
750 /* If we only have valid padding, nothing to do. */
755 * Allocate space in the primary vnet area. Copy in our
756 * initialization from the data section and then initialize
757 * all per-vnet storage from that.
759 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size);
760 if (ef->vnet_base == 0) {
761 printf("%s: vnet module space is out of space; "
762 "cannot allocate %d for %s\n",
763 __func__, size, ef->lf.pathname);
766 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size);
767 vnet_data_copy((void *)ef->vnet_base, size);
768 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
777 * Apply the specified protection to the loadable segments of a preloaded linker
781 preload_protect(elf_file_t ef, vm_prot_t prot)
783 #if defined(__aarch64__) || defined(__amd64__)
785 Elf_Phdr *phdr, *phlimit;
790 hdr = (Elf_Ehdr *)ef->address;
791 phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff);
792 phlimit = phdr + hdr->e_phnum;
793 for (; phdr < phlimit; phdr++) {
794 if (phdr->p_type != PT_LOAD)
797 nprot = prot | VM_PROT_READ;
798 if ((phdr->p_flags & PF_W) != 0)
799 nprot |= VM_PROT_WRITE;
800 if ((phdr->p_flags & PF_X) != 0)
801 nprot |= VM_PROT_EXECUTE;
802 error = pmap_change_prot((vm_offset_t)ef->address +
803 phdr->p_vaddr, round_page(phdr->p_memsz), nprot);
815 * Locate the ARM exception/unwind table info for DDB and stack(9) use by
816 * searching for the section header that describes it. There may be no unwind
817 * info, for example in a module containing only data.
820 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr)
824 for (i = 0; i < nhdr; i++) {
825 if (shdr[i].sh_type == SHT_ARM_EXIDX) {
826 lf->exidx_addr = shdr[i].sh_addr + lf->address;
827 lf->exidx_size = shdr[i].sh_size;
834 * Locate the section headers metadata in a preloaded module, then use it to
835 * locate the exception/unwind table in the module. The size of the metadata
836 * block is stored in a uint32 word immediately before the data itself, and a
837 * comment in preload_search_info() says it is safe to rely on that.
840 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr)
846 modinfo = (uint32_t *)preload_search_info(modptr,
847 MODINFO_METADATA | MODINFOMD_SHDR);
848 if (modinfo != NULL) {
849 shdr = (Elf_Shdr *)modinfo;
850 nhdr = modinfo[-1] / sizeof(Elf_Shdr);
851 link_elf_locate_exidx(lf, shdr, nhdr);
858 link_elf_link_preload(linker_class_t cls, const char *filename,
859 linker_file_t *result)
861 Elf_Addr *ctors_addrp;
862 Elf_Size *ctors_sizep;
863 caddr_t modptr, baseptr, sizeptr, dynptr;
870 /* Look to see if we have the file preloaded */
871 modptr = preload_search_by_name(filename);
875 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
876 baseptr = preload_search_info(modptr, MODINFO_ADDR);
877 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
878 dynptr = preload_search_info(modptr,
879 MODINFO_METADATA | MODINFOMD_DYNAMIC);
881 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
882 strcmp(type, "elf module") != 0))
884 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
887 lf = linker_make_file(filename, &link_elf_class);
891 ef = (elf_file_t) lf;
894 ef->address = *(caddr_t *)baseptr;
895 #ifdef SPARSE_MAPPING
898 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
899 ef->dynamic = (Elf_Dyn *)dp;
900 lf->address = ef->address;
901 lf->size = *(size_t *)sizeptr;
903 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
904 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
905 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
906 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
907 if (ctors_addrp != NULL && ctors_sizep != NULL) {
908 lf->ctors_addr = ef->address + *ctors_addrp;
909 lf->ctors_size = *ctors_sizep;
913 link_elf_locate_exidx_preload(lf, modptr);
916 error = parse_dynamic(ef);
918 error = parse_dpcpu(ef);
921 error = parse_vnet(ef);
924 error = preload_protect(ef, VM_PROT_ALL);
926 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
929 link_elf_reloc_local(lf);
935 link_elf_link_preload_finish(linker_file_t lf)
940 ef = (elf_file_t) lf;
941 error = relocate_file(ef);
943 error = preload_protect(ef, VM_PROT_NONE);
946 (void)link_elf_preload_parse_symbols(ef);
948 return (link_elf_link_common_finish(lf));
952 link_elf_load_file(linker_class_t cls, const char* filename,
953 linker_file_t* result)
956 struct thread* td = curthread; /* XXX */
958 caddr_t firstpage, segbase;
962 Elf_Phdr *segs[MAXSEGS];
968 Elf_Addr base_vlimit;
986 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename);
988 error = vn_open(&nd, &flags, 0, NULL);
992 if (nd.ni_vp->v_type != VREG) {
998 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
1006 * Read the elf header from the file.
1008 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
1009 hdr = (Elf_Ehdr *)firstpage;
1010 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
1011 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1013 nbytes = PAGE_SIZE - resid;
1017 if (!IS_ELF(*hdr)) {
1022 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
1023 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
1024 link_elf_error(filename, "Unsupported file layout");
1028 if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
1029 hdr->e_version != EV_CURRENT) {
1030 link_elf_error(filename, "Unsupported file version");
1034 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
1038 if (hdr->e_machine != ELF_TARG_MACH) {
1039 link_elf_error(filename, "Unsupported machine");
1045 * We rely on the program header being in the first page.
1046 * This is not strictly required by the ABI specification, but
1047 * it seems to always true in practice. And, it simplifies
1048 * things considerably.
1050 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
1051 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
1052 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
1053 link_elf_error(filename, "Unreadable program headers");
1056 * Scan the program header entries, and save key information.
1058 * We rely on there being exactly two load segments, text and data,
1061 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
1062 phlimit = phdr + hdr->e_phnum;
1065 while (phdr < phlimit) {
1066 switch (phdr->p_type) {
1068 if (nsegs == MAXSEGS) {
1069 link_elf_error(filename, "Too many sections");
1074 * XXX: We just trust they come in right order ??
1091 if (phdyn == NULL) {
1092 link_elf_error(filename, "Object is not dynamically-linked");
1097 link_elf_error(filename, "No sections");
1103 * Allocate the entire address space of the object, to stake
1104 * out our contiguous region, and to establish the base
1105 * address for relocation.
1107 base_vaddr = trunc_page(segs[0]->p_vaddr);
1108 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
1109 segs[nsegs - 1]->p_memsz);
1110 mapsize = base_vlimit - base_vaddr;
1112 lf = linker_make_file(filename, &link_elf_class);
1118 ef = (elf_file_t) lf;
1119 #ifdef SPARSE_MAPPING
1120 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, mapsize, VM_PROT_ALL,
1121 0, thread0.td_ucred);
1122 if (ef->object == NULL) {
1127 mapbase = (caddr_t)KERNBASE;
1129 mapbase = (caddr_t)vm_map_min(kernel_map);
1132 * Mapping protections are downgraded after relocation processing.
1134 error = vm_map_find(kernel_map, ef->object, 0,
1135 (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE,
1136 VM_PROT_ALL, VM_PROT_ALL, 0);
1138 vm_object_deallocate(ef->object);
1143 mapbase = malloc_exec(mapsize, M_LINKER, M_WAITOK);
1145 ef->address = mapbase;
1148 * Read the text and data sections and zero the bss.
1150 for (i = 0; i < nsegs; i++) {
1151 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1153 #ifdef SPARSE_MAPPING
1155 * Consecutive segments may have different mapping permissions,
1156 * so be strict and verify that their mappings do not overlap.
1158 if (((vm_offset_t)segbase & PAGE_MASK) != 0) {
1163 error = vm_map_wire(kernel_map,
1164 (vm_offset_t)segbase,
1165 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1166 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
1167 if (error != KERN_SUCCESS) {
1173 error = vn_rdwr(UIO_READ, nd.ni_vp,
1174 segbase, segs[i]->p_filesz, segs[i]->p_offset,
1175 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1179 bzero(segbase + segs[i]->p_filesz,
1180 segs[i]->p_memsz - segs[i]->p_filesz);
1184 /* Update profiling information with the new text segment. */
1186 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
1191 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
1193 lf->address = ef->address;
1196 error = parse_dynamic(ef);
1199 error = parse_dpcpu(ef);
1203 error = parse_vnet(ef);
1207 link_elf_reloc_local(lf);
1209 VOP_UNLOCK(nd.ni_vp);
1210 error = linker_load_dependencies(lf);
1211 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1214 error = relocate_file(ef);
1218 #ifdef SPARSE_MAPPING
1220 * Downgrade permissions on text segment mappings now that relocation
1221 * processing is complete. Restrict permissions on read-only segments.
1223 for (i = 0; i < nsegs; i++) {
1226 if (segs[i]->p_type != PT_LOAD)
1229 prot = VM_PROT_READ;
1230 if ((segs[i]->p_flags & PF_W) != 0)
1231 prot |= VM_PROT_WRITE;
1232 if ((segs[i]->p_flags & PF_X) != 0)
1233 prot |= VM_PROT_EXECUTE;
1234 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1235 error = vm_map_protect(kernel_map,
1236 (vm_offset_t)segbase,
1237 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1238 prot, 0, VM_MAP_PROTECT_SET_PROT);
1239 if (error != KERN_SUCCESS) {
1247 * Try and load the symbol table if it's present. (you can
1250 nbytes = hdr->e_shnum * hdr->e_shentsize;
1251 if (nbytes == 0 || hdr->e_shoff == 0)
1253 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1254 error = vn_rdwr(UIO_READ, nd.ni_vp,
1255 (caddr_t)shdr, nbytes, hdr->e_shoff,
1256 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1261 /* Read section string table */
1262 shstrindex = hdr->e_shstrndx;
1263 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1264 shdr[shstrindex].sh_size != 0) {
1265 nbytes = shdr[shstrindex].sh_size;
1266 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1267 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1268 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1269 td->td_ucred, NOCRED, &resid, td);
1276 for (i = 0; i < hdr->e_shnum; i++) {
1277 if (shdr[i].sh_type == SHT_SYMTAB) {
1279 symstrindex = shdr[i].sh_link;
1280 } else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1281 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1282 /* Record relocated address and size of .ctors. */
1283 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1284 lf->ctors_size = shdr[i].sh_size;
1287 if (symtabindex < 0 || symstrindex < 0)
1290 symcnt = shdr[symtabindex].sh_size;
1291 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1292 strcnt = shdr[symstrindex].sh_size;
1293 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1295 error = vn_rdwr(UIO_READ, nd.ni_vp,
1296 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1297 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1301 error = vn_rdwr(UIO_READ, nd.ni_vp,
1302 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1303 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1308 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1309 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1310 ef->ddbstrcnt = strcnt;
1311 ef->ddbstrtab = ef->strbase;
1316 link_elf_locate_exidx(lf, shdr, hdr->e_shnum);
1319 error = link_elf_link_common_finish(lf);
1326 VOP_UNLOCK(nd.ni_vp);
1327 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1328 if (error != 0 && lf != NULL)
1329 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1330 free(shdr, M_LINKER);
1331 free(firstpage, M_LINKER);
1332 free(shstrs, M_LINKER);
1338 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1342 KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class,
1343 ("elf_relocaddr: unexpected linker file %p", lf));
1345 ef = (elf_file_t)lf;
1346 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1347 return ((x - ef->pcpu_start) + ef->pcpu_base);
1349 if (x >= ef->vnet_start && x < ef->vnet_stop)
1350 return ((x - ef->vnet_start) + ef->vnet_base);
1356 link_elf_unload_file(linker_file_t file)
1358 elf_file_t ef = (elf_file_t) file;
1360 if (ef->pcpu_base != 0) {
1361 dpcpu_free((void *)ef->pcpu_base,
1362 ef->pcpu_stop - ef->pcpu_start);
1363 elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1366 if (ef->vnet_base != 0) {
1367 vnet_data_free((void *)ef->vnet_base,
1368 ef->vnet_stop - ef->vnet_start);
1369 elf_set_delete(&set_vnet_list, ef->vnet_start);
1373 if (ef->gdb.l_ld != NULL) {
1374 GDB_STATE(RT_DELETE);
1375 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1376 link_elf_delete_gdb(&ef->gdb);
1377 GDB_STATE(RT_CONSISTENT);
1381 /* Notify MD code that a module is being unloaded. */
1382 elf_cpu_unload_file(file);
1384 if (ef->preloaded) {
1385 link_elf_unload_preload(file);
1389 #ifdef SPARSE_MAPPING
1390 if (ef->object != NULL) {
1391 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1392 (vm_offset_t) ef->address
1393 + (ef->object->size << PAGE_SHIFT));
1396 free(ef->address, M_LINKER);
1398 free(ef->symbase, M_LINKER);
1399 free(ef->strbase, M_LINKER);
1400 free(ef->ctftab, M_LINKER);
1401 free(ef->ctfoff, M_LINKER);
1402 free(ef->typoff, M_LINKER);
1406 link_elf_unload_preload(linker_file_t file)
1409 if (file->pathname != NULL)
1410 preload_delete_name(file->pathname);
1414 symbol_name(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 (ef->strtab + ref->st_name);
1426 symbol_type(elf_file_t ef, Elf_Size r_info)
1430 if (ELF_R_SYM(r_info)) {
1431 ref = ef->symtab + ELF_R_SYM(r_info);
1432 return (ELF_ST_TYPE(ref->st_info));
1434 return (STT_NOTYPE);
1438 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc,
1442 const Elf_Rela *rela;
1443 const char *symname;
1445 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \
1446 for ((iter) = (tbl); (iter) != NULL && \
1447 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \
1448 if ((symbol_type(ef, (iter)->r_info) == \
1450 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \
1452 if (reloc(&ef->lf, (Elf_Addr)ef->address, \
1453 (iter), (type), lookup)) { \
1454 symname = symbol_name(ef, (iter)->r_info); \
1455 printf("link_elf: symbol %s undefined\n", \
1462 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL);
1463 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA);
1464 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL);
1465 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 * Hash function for symbol table lookup. Don't even think about changing
1485 * this. It is specified by the System V ABI.
1487 static unsigned long
1488 elf_hash(const char *name)
1490 const unsigned char *p = (const unsigned char *) name;
1491 unsigned long h = 0;
1494 while (*p != '\0') {
1495 h = (h << 4) + *p++;
1496 if ((g = h & 0xf0000000) != 0)
1504 link_elf_lookup_symbol1(linker_file_t lf, const char *name, c_linker_sym_t *sym,
1507 elf_file_t ef = (elf_file_t) lf;
1508 unsigned long symnum;
1509 const Elf_Sym* symp;
1513 /* If we don't have a hash, bail. */
1514 if (ef->buckets == NULL || ef->nbuckets == 0) {
1515 printf("link_elf_lookup_symbol: missing symbol hash table\n");
1519 /* First, search hashed global symbols */
1520 hash = elf_hash(name);
1521 symnum = ef->buckets[hash % ef->nbuckets];
1523 while (symnum != STN_UNDEF) {
1524 if (symnum >= ef->nchains) {
1525 printf("%s: corrupt symbol table\n", __func__);
1529 symp = ef->symtab + symnum;
1530 if (symp->st_name == 0) {
1531 printf("%s: corrupt symbol table\n", __func__);
1535 strp = ef->strtab + symp->st_name;
1537 if (strcmp(name, strp) == 0) {
1538 if (symp->st_shndx != SHN_UNDEF ||
1539 (symp->st_value != 0 &&
1540 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1541 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1543 ELF_ST_BIND(symp->st_info) != STB_LOCAL) {
1544 *sym = (c_linker_sym_t) symp;
1551 symnum = ef->chains[symnum];
1558 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1560 if (link_elf_leak_locals)
1561 return (link_elf_lookup_debug_symbol(lf, name, sym));
1562 return (link_elf_lookup_symbol1(lf, name, sym, false));
1566 link_elf_lookup_debug_symbol(linker_file_t lf, const char *name,
1567 c_linker_sym_t *sym)
1569 elf_file_t ef = (elf_file_t)lf;
1570 const Elf_Sym* symp;
1574 if (link_elf_lookup_symbol1(lf, name, sym, true) == 0)
1577 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1578 strp = ef->ddbstrtab + symp->st_name;
1579 if (strcmp(name, strp) == 0) {
1580 if (symp->st_shndx != SHN_UNDEF ||
1581 (symp->st_value != 0 &&
1582 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1583 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1584 *sym = (c_linker_sym_t) symp;
1595 link_elf_symbol_values1(linker_file_t lf, c_linker_sym_t sym,
1596 linker_symval_t *symval, bool see_local)
1602 ef = (elf_file_t)lf;
1603 es = (const Elf_Sym *)sym;
1604 if (es >= ef->symtab && es < ef->symtab + ef->nchains) {
1605 if (!see_local && ELF_ST_BIND(es->st_info) == STB_LOCAL)
1607 symval->name = ef->strtab + es->st_name;
1608 val = (caddr_t)ef->address + es->st_value;
1609 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1610 val = ((caddr_t (*)(void))val)();
1611 symval->value = val;
1612 symval->size = es->st_size;
1619 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1620 linker_symval_t *symval)
1622 if (link_elf_leak_locals)
1623 return (link_elf_debug_symbol_values(lf, sym, symval));
1624 return (link_elf_symbol_values1(lf, sym, symval, false));
1628 link_elf_debug_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1629 linker_symval_t *symval)
1631 elf_file_t ef = (elf_file_t)lf;
1632 const Elf_Sym *es = (const Elf_Sym *)sym;
1635 if (link_elf_symbol_values1(lf, sym, symval, true) == 0)
1637 if (ef->symtab == ef->ddbsymtab)
1640 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1641 symval->name = ef->ddbstrtab + es->st_name;
1642 val = (caddr_t)ef->address + es->st_value;
1643 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1644 val = ((caddr_t (*)(void))val)();
1645 symval->value = val;
1646 symval->size = es->st_size;
1653 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1654 c_linker_sym_t *sym, long *diffp)
1656 elf_file_t ef = (elf_file_t)lf;
1657 u_long off = (uintptr_t)(void *)value;
1661 const Elf_Sym *best = NULL;
1664 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1665 if (es->st_name == 0)
1667 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1668 if (off >= st_value) {
1669 if (off - st_value < diff) {
1670 diff = off - st_value;
1674 } else if (off - st_value == diff) {
1683 *sym = (c_linker_sym_t) best;
1689 * Look up a linker set on an ELF system.
1692 link_elf_lookup_set(linker_file_t lf, const char *name,
1693 void ***startp, void ***stopp, int *countp)
1696 linker_symval_t symval;
1698 void **start, **stop;
1699 int len, error = 0, count;
1701 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1702 setsym = malloc(len, M_LINKER, M_WAITOK);
1704 /* get address of first entry */
1705 snprintf(setsym, len, "%s%s", "__start_set_", name);
1706 error = link_elf_lookup_symbol(lf, setsym, &sym);
1709 link_elf_symbol_values(lf, sym, &symval);
1710 if (symval.value == 0) {
1714 start = (void **)symval.value;
1716 /* get address of last entry */
1717 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1718 error = link_elf_lookup_symbol(lf, setsym, &sym);
1721 link_elf_symbol_values(lf, sym, &symval);
1722 if (symval.value == 0) {
1726 stop = (void **)symval.value;
1728 /* and the number of entries */
1729 count = stop - start;
1740 free(setsym, M_LINKER);
1745 link_elf_each_function_name(linker_file_t file,
1746 int (*callback)(const char *, void *), void *opaque)
1748 elf_file_t ef = (elf_file_t)file;
1749 const Elf_Sym *symp;
1752 /* Exhaustive search */
1753 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1754 if (symp->st_value != 0 &&
1755 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1756 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1757 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1766 link_elf_each_function_nameval(linker_file_t file,
1767 linker_function_nameval_callback_t callback, void *opaque)
1769 linker_symval_t symval;
1770 elf_file_t ef = (elf_file_t)file;
1771 const Elf_Sym *symp;
1774 /* Exhaustive search */
1775 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1776 if (symp->st_value != 0 &&
1777 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1778 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1779 error = link_elf_debug_symbol_values(file,
1780 (c_linker_sym_t) symp, &symval);
1782 error = callback(file, i, &symval, opaque);
1791 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1793 elf_file_t ef = (elf_file_t)lf;
1795 if (symidx >= ef->nchains)
1797 return (ef->symtab + symidx);
1801 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1803 elf_file_t ef = (elf_file_t)lf;
1806 if (symidx >= ef->nchains)
1808 sym = ef->symtab + symidx;
1809 return (ef->strtab + sym->st_name);
1813 * Symbol lookup function that can be used when the symbol index is known (ie
1814 * in relocations). It uses the symbol index instead of doing a fully fledged
1815 * hash table based lookup when such is valid. For example for local symbols.
1816 * This is not only more efficient, it's also more correct. It's not always
1817 * the case that the symbol can be found through the hash table.
1820 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1822 elf_file_t ef = (elf_file_t)lf;
1825 Elf_Addr addr, start, base;
1827 /* Don't even try to lookup the symbol if the index is bogus. */
1828 if (symidx >= ef->nchains) {
1833 sym = ef->symtab + symidx;
1836 * Don't do a full lookup when the symbol is local. It may even
1837 * fail because it may not be found through the hash table.
1839 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1840 /* Force lookup failure when we have an insanity. */
1841 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1845 *res = ((Elf_Addr)ef->address + sym->st_value);
1850 * XXX we can avoid doing a hash table based lookup for global
1851 * symbols as well. This however is not always valid, so we'll
1852 * just do it the hard way for now. Performance tweaks can
1856 symbol = ef->strtab + sym->st_name;
1858 /* Force a lookup failure if the symbol name is bogus. */
1864 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1865 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1870 if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1871 addr = addr - start + base;
1873 else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1874 addr = addr - start + base;
1881 link_elf_reloc_local(linker_file_t lf)
1883 const Elf_Rel *rellim;
1885 const Elf_Rela *relalim;
1886 const Elf_Rela *rela;
1887 elf_file_t ef = (elf_file_t)lf;
1889 /* Perform relocations without addend if there are any: */
1890 if ((rel = ef->rel) != NULL) {
1891 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1892 while (rel < rellim) {
1893 elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1894 ELF_RELOC_REL, elf_lookup);
1899 /* Perform relocations with addend if there are any: */
1900 if ((rela = ef->rela) != NULL) {
1901 relalim = (const Elf_Rela *)
1902 ((const char *)ef->rela + ef->relasize);
1903 while (rela < relalim) {
1904 elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1905 ELF_RELOC_RELA, elf_lookup);
1912 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1914 elf_file_t ef = (elf_file_t)lf;
1916 *symtab = ef->ddbsymtab;
1918 if (*symtab == NULL)
1921 return (ef->ddbsymcnt);
1925 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1927 elf_file_t ef = (elf_file_t)lf;
1929 *strtab = ef->ddbstrtab;
1931 if (*strtab == NULL)
1934 return (ef->ddbstrcnt);
1937 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) || defined(__powerpc__)
1939 * Use this lookup routine when performing relocations early during boot.
1940 * The generic lookup routine depends on kobj, which is not initialized
1944 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused,
1948 const Elf_Sym *symp;
1951 ef = (elf_file_t)lf;
1952 symp = ef->symtab + symidx;
1953 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) {
1954 val = (caddr_t)ef->address + symp->st_value;
1955 *res = ((Elf_Addr (*)(void))val)();
1962 link_elf_ireloc(caddr_t kmdp)
1964 struct elf_file eff;
1969 bzero_early(ef, sizeof(*ef));
1972 ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
1974 #ifdef RELOCATABLE_KERNEL
1975 ef->address = (caddr_t) (__startkernel - KERNBASE);
1981 link_elf_preload_parse_symbols(ef);
1982 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true);
1985 #if defined(__aarch64__) || defined(__amd64__)
1987 link_elf_late_ireloc(void)
1991 KASSERT(linker_kernel_file != NULL,
1992 ("link_elf_late_ireloc: No kernel linker file found"));
1993 ef = (elf_file_t)linker_kernel_file;
1995 relocate_file1(ef, elf_lookup_ifunc, elf_reloc_late, true);