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>
37 #include <sys/kernel.h>
39 #include <sys/malloc.h>
43 #include <sys/mutex.h>
44 #include <sys/mount.h>
47 #include <sys/namei.h>
48 #include <sys/fcntl.h>
49 #include <sys/vnode.h>
50 #include <sys/linker.h>
51 #include <sys/sysctl.h>
53 #include <machine/elf.h>
57 #include <security/mac/mac_framework.h>
60 #include <vm/vm_param.h>
62 #include <vm/vm_object.h>
63 #include <vm/vm_kern.h>
64 #include <vm/vm_extern.h>
67 #include <vm/vm_map.h>
69 #include <sys/link_elf.h>
71 #include "linker_if.h"
75 typedef struct elf_file {
76 struct linker_file lf; /* Common fields */
77 int preloaded; /* Was file pre-loaded */
78 caddr_t address; /* Relocation address */
80 vm_object_t object; /* VM object to hold file pages */
82 Elf_Dyn *dynamic; /* Symbol table etc. */
83 Elf_Hashelt nbuckets; /* DT_HASH info */
85 const Elf_Hashelt *buckets;
86 const Elf_Hashelt *chains;
88 caddr_t strtab; /* DT_STRTAB */
89 int strsz; /* DT_STRSZ */
90 const Elf_Sym *symtab; /* DT_SYMTAB */
91 Elf_Addr *got; /* DT_PLTGOT */
92 const Elf_Rel *pltrel; /* DT_JMPREL */
93 int pltrelsize; /* DT_PLTRELSZ */
94 const Elf_Rela *pltrela; /* DT_JMPREL */
95 int pltrelasize; /* DT_PLTRELSZ */
96 const Elf_Rel *rel; /* DT_REL */
97 int relsize; /* DT_RELSZ */
98 const Elf_Rela *rela; /* DT_RELA */
99 int relasize; /* DT_RELASZ */
101 const Elf_Sym *ddbsymtab; /* The symbol table we are using */
102 long ddbsymcnt; /* Number of symbols */
103 caddr_t ddbstrtab; /* String table */
104 long ddbstrcnt; /* number of bytes in string table */
105 caddr_t symbase; /* malloc'ed symbold base */
106 caddr_t strbase; /* malloc'ed string base */
107 caddr_t ctftab; /* CTF table */
108 long ctfcnt; /* number of bytes in CTF table */
109 caddr_t ctfoff; /* CTF offset table */
110 caddr_t typoff; /* Type offset table */
111 long typlen; /* Number of type entries. */
112 Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */
113 Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */
114 Elf_Addr pcpu_base; /* Relocated pcpu set address. */
116 Elf_Addr vnet_start; /* Pre-relocation vnet set start. */
117 Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */
118 Elf_Addr vnet_base; /* Relocated vnet set address. */
121 struct link_map gdb; /* hooks for gdb */
129 TAILQ_ENTRY(elf_set) es_link;
132 TAILQ_HEAD(elf_set_head, elf_set);
134 #include <kern/kern_ctf.c>
136 static int link_elf_link_common_finish(linker_file_t);
137 static int link_elf_link_preload(linker_class_t cls,
138 const char *, linker_file_t *);
139 static int link_elf_link_preload_finish(linker_file_t);
140 static int link_elf_load_file(linker_class_t, const char *,
142 static int link_elf_lookup_symbol(linker_file_t, const char *,
144 static int link_elf_lookup_debug_symbol(linker_file_t, const char *,
146 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
148 static int link_elf_debug_symbol_values(linker_file_t, c_linker_sym_t,
150 static int link_elf_search_symbol(linker_file_t, caddr_t,
151 c_linker_sym_t *, long *);
153 static void link_elf_unload_file(linker_file_t);
154 static void link_elf_unload_preload(linker_file_t);
155 static int link_elf_lookup_set(linker_file_t, const char *,
156 void ***, void ***, int *);
157 static int link_elf_each_function_name(linker_file_t,
158 int (*)(const char *, void *), void *);
159 static int link_elf_each_function_nameval(linker_file_t,
160 linker_function_nameval_callback_t, void *);
161 static void link_elf_reloc_local(linker_file_t);
162 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
163 static long link_elf_strtab_get(linker_file_t, caddr_t *);
164 static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
166 static kobj_method_t link_elf_methods[] = {
167 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
168 KOBJMETHOD(linker_lookup_debug_symbol, link_elf_lookup_debug_symbol),
169 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
170 KOBJMETHOD(linker_debug_symbol_values, link_elf_debug_symbol_values),
171 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
172 KOBJMETHOD(linker_unload, link_elf_unload_file),
173 KOBJMETHOD(linker_load_file, link_elf_load_file),
174 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
175 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
176 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
177 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
178 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
179 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
180 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
181 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
185 static struct linker_class link_elf_class = {
186 #if ELF_TARG_CLASS == ELFCLASS32
191 link_elf_methods, sizeof(struct elf_file)
194 static bool link_elf_leak_locals = true;
195 SYSCTL_BOOL(_debug, OID_AUTO, link_elf_leak_locals,
196 CTLFLAG_RWTUN, &link_elf_leak_locals, 0,
197 "Allow local symbols to participate in global module symbol resolution");
199 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase,
200 const void *data, int type, elf_lookup_fn lookup);
202 static int parse_dynamic(elf_file_t);
203 static int relocate_file(elf_file_t);
204 static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup,
205 elf_reloc_fn reloc, bool ifuncs);
206 static int link_elf_preload_parse_symbols(elf_file_t);
208 static struct elf_set_head set_pcpu_list;
210 static struct elf_set_head set_vnet_list;
214 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
216 struct elf_set *set, *iter;
218 set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
219 set->es_start = start;
223 TAILQ_FOREACH(iter, list, es_link) {
224 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
225 (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
226 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
227 (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
228 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
230 if (iter->es_start > set->es_start) {
231 TAILQ_INSERT_BEFORE(iter, set, es_link);
237 TAILQ_INSERT_TAIL(list, set, es_link);
241 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
245 TAILQ_FOREACH(set, list, es_link) {
246 if (addr < set->es_start)
248 if (addr < set->es_stop) {
249 *start = set->es_start;
250 *base = set->es_base;
259 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
263 TAILQ_FOREACH(set, list, es_link) {
264 if (start < set->es_start)
266 if (start == set->es_start) {
267 TAILQ_REMOVE(list, set, es_link);
272 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
277 static void r_debug_state(struct r_debug *, struct link_map *);
280 * A list of loaded modules for GDB to use for loading symbols.
282 struct r_debug r_debug;
284 #define GDB_STATE(s) do { \
285 r_debug.r_state = s; r_debug_state(NULL, NULL); \
289 * Function for the debugger to set a breakpoint on to gain control.
292 r_debug_state(struct r_debug *dummy_one __unused,
293 struct link_map *dummy_two __unused)
298 link_elf_add_gdb(struct link_map *l)
300 struct link_map *prev;
304 if (r_debug.r_map == NULL) {
309 /* Append to list. */
310 for (prev = r_debug.r_map;
311 prev->l_next != NULL;
320 link_elf_delete_gdb(struct link_map *l)
322 if (l->l_prev == NULL) {
324 if ((r_debug.r_map = l->l_next) != NULL)
325 l->l_next->l_prev = NULL;
327 /* Remove any but first. */
328 if ((l->l_prev->l_next = l->l_next) != NULL)
329 l->l_next->l_prev = l->l_prev;
335 * The kernel symbol table starts here.
337 extern struct _dynamic _DYNAMIC;
340 link_elf_error(const char *filename, const char *s)
342 if (filename == NULL)
343 printf("kldload: %s\n", s);
345 printf("kldload: %s: %s\n", filename, s);
349 link_elf_invoke_ctors(caddr_t addr, size_t size)
354 if (addr == NULL || size == 0)
356 cnt = size / sizeof(*ctor);
358 for (i = 0; i < cnt; i++) {
365 * Actions performed after linking/loading both the preloaded kernel and any
366 * modules; whether preloaded or dynamicly loaded.
369 link_elf_link_common_finish(linker_file_t lf)
372 elf_file_t ef = (elf_file_t)lf;
377 /* Notify MD code that a module is being loaded. */
378 error = elf_cpu_load_file(lf);
384 ef->gdb.l_addr = lf->address;
385 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
386 strcpy(newfilename, lf->filename);
387 ef->gdb.l_name = newfilename;
388 ef->gdb.l_ld = ef->dynamic;
389 link_elf_add_gdb(&ef->gdb);
390 GDB_STATE(RT_CONSISTENT);
394 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
398 #ifdef RELOCATABLE_KERNEL
400 * __startkernel and __endkernel are symbols set up as relocation canaries.
402 * They are defined in locore to reference linker script symbols at the
403 * beginning and end of the LOAD area. This has the desired side effect of
404 * giving us variables that have relative relocations pointing at them, so
405 * relocation of the kernel object will cause the variables to be updated
406 * automatically by the runtime linker when we initialize.
408 * There are two main reasons to relocate the kernel:
409 * 1) If the loader needed to load the kernel at an alternate load address.
410 * 2) If the kernel is switching address spaces on machines like POWER9
411 * under Radix where the high bits of the effective address are used to
412 * differentiate between hypervisor, host, guest, and problem state.
414 extern vm_offset_t __startkernel, __endkernel;
417 static unsigned long kern_relbase = KERNBASE;
419 SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD,
420 SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address");
421 SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD,
422 &kern_relbase, 0, "Kernel relocated base address");
425 link_elf_init(void* arg)
428 Elf_Addr *ctors_addrp;
429 Elf_Size *ctors_sizep;
430 caddr_t modptr, baseptr, sizeptr;
434 linker_add_class(&link_elf_class);
436 dp = (Elf_Dyn *)&_DYNAMIC;
438 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
440 modptr = preload_search_by_type("elf kernel");
441 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
444 linker_kernel_file = linker_make_file(modname, &link_elf_class);
445 if (linker_kernel_file == NULL)
446 panic("%s: Can't create linker structures for kernel",
449 ef = (elf_file_t) linker_kernel_file;
451 #ifdef RELOCATABLE_KERNEL
452 /* Compute relative displacement */
453 ef->address = (caddr_t) (__startkernel - KERNBASE);
457 #ifdef SPARSE_MAPPING
464 #ifdef RELOCATABLE_KERNEL
465 linker_kernel_file->address = (caddr_t)__startkernel;
466 linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
467 kern_relbase = (unsigned long)__startkernel;
469 linker_kernel_file->address += KERNBASE;
470 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
473 if (modptr != NULL) {
475 baseptr = preload_search_info(modptr, MODINFO_ADDR);
477 linker_kernel_file->address = *(caddr_t *)baseptr;
478 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
480 linker_kernel_file->size = *(size_t *)sizeptr;
481 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
482 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
483 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
484 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
485 if (ctors_addrp != NULL && ctors_sizep != NULL) {
486 linker_kernel_file->ctors_addr = ef->address +
488 linker_kernel_file->ctors_size = *ctors_sizep;
491 (void)link_elf_preload_parse_symbols(ef);
494 r_debug.r_map = NULL;
495 r_debug.r_brk = r_debug_state;
496 r_debug.r_state = RT_CONSISTENT;
499 (void)link_elf_link_common_finish(linker_kernel_file);
500 linker_kernel_file->flags |= LINKER_FILE_LINKED;
501 TAILQ_INIT(&set_pcpu_list);
503 TAILQ_INIT(&set_vnet_list);
507 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL);
510 link_elf_preload_parse_symbols(elf_file_t ef)
513 caddr_t ssym, esym, base;
519 if (ef->modptr == NULL)
521 pointer = preload_search_info(ef->modptr,
522 MODINFO_METADATA | MODINFOMD_SSYM);
525 ssym = *(caddr_t *)pointer;
526 pointer = preload_search_info(ef->modptr,
527 MODINFO_METADATA | MODINFOMD_ESYM);
530 esym = *(caddr_t *)pointer;
534 symcnt = *(long *)base;
535 base += sizeof(long);
536 symtab = (Elf_Sym *)base;
537 base += roundup(symcnt, sizeof(long));
539 if (base > esym || base < ssym) {
540 printf("Symbols are corrupt!\n");
544 strcnt = *(long *)base;
545 base += sizeof(long);
547 base += roundup(strcnt, sizeof(long));
549 if (base > esym || base < ssym) {
550 printf("Symbols are corrupt!\n");
554 ef->ddbsymtab = symtab;
555 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
556 ef->ddbstrtab = strtab;
557 ef->ddbstrcnt = strcnt;
563 parse_dynamic(elf_file_t ef)
566 int plttype = DT_REL;
568 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
572 /* From src/libexec/rtld-elf/rtld.c */
573 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
574 (ef->address + dp->d_un.d_ptr);
575 ef->nbuckets = hashtab[0];
576 ef->nchains = hashtab[1];
577 ef->buckets = hashtab + 2;
578 ef->chains = ef->buckets + ef->nbuckets;
582 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
585 ef->strsz = dp->d_un.d_val;
588 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
591 if (dp->d_un.d_val != sizeof(Elf_Sym))
595 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
598 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
601 ef->relsize = dp->d_un.d_val;
604 if (dp->d_un.d_val != sizeof(Elf_Rel))
608 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
611 ef->pltrelsize = dp->d_un.d_val;
614 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
617 ef->relasize = dp->d_un.d_val;
620 if (dp->d_un.d_val != sizeof(Elf_Rela))
624 plttype = dp->d_un.d_val;
625 if (plttype != DT_REL && plttype != DT_RELA)
630 dp->d_un.d_ptr = (Elf_Addr)&r_debug;
636 if (plttype == DT_RELA) {
637 ef->pltrela = (const Elf_Rela *)ef->pltrel;
639 ef->pltrelasize = ef->pltrelsize;
643 ef->ddbsymtab = ef->symtab;
644 ef->ddbsymcnt = ef->nchains;
645 ef->ddbstrtab = ef->strtab;
646 ef->ddbstrcnt = ef->strsz;
648 return elf_cpu_parse_dynamic(ef->address, ef->dynamic);
651 #define LS_PADDING 0x90909090
653 parse_dpcpu(elf_file_t ef)
656 #if defined(__i386__)
662 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
663 (void ***)&ef->pcpu_stop, NULL);
664 /* Error just means there is no pcpu set to relocate. */
667 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start;
671 #if defined(__i386__)
672 /* In case we do find __start/stop_set_ symbols double-check. */
674 uprintf("Kernel module '%s' must be recompiled with "
675 "linker script\n", ef->lf.pathname);
679 /* Padding from linker-script correct? */
680 pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad));
681 if (pad != LS_PADDING) {
682 uprintf("Kernel module '%s' must be recompiled with "
683 "linker script, invalid padding %#04x (%#04x)\n",
684 ef->lf.pathname, pad, LS_PADDING);
687 /* If we only have valid padding, nothing to do. */
692 * Allocate space in the primary pcpu area. Copy in our
693 * initialization from the data section and then initialize
694 * all per-cpu storage from that.
696 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size);
697 if (ef->pcpu_base == 0) {
698 printf("%s: pcpu module space is out of space; "
699 "cannot allocate %d for %s\n",
700 __func__, size, ef->lf.pathname);
703 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size);
704 dpcpu_copy((void *)ef->pcpu_base, size);
705 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
713 parse_vnet(elf_file_t ef)
716 #if defined(__i386__)
722 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
723 (void ***)&ef->vnet_stop, NULL);
724 /* Error just means there is no vnet data set to relocate. */
727 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
731 #if defined(__i386__)
732 /* In case we do find __start/stop_set_ symbols double-check. */
734 uprintf("Kernel module '%s' must be recompiled with "
735 "linker script\n", ef->lf.pathname);
739 /* Padding from linker-script correct? */
740 pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad));
741 if (pad != LS_PADDING) {
742 uprintf("Kernel module '%s' must be recompiled with "
743 "linker script, invalid padding %#04x (%#04x)\n",
744 ef->lf.pathname, pad, LS_PADDING);
747 /* If we only have valid padding, nothing to do. */
752 * Allocate space in the primary vnet area. Copy in our
753 * initialization from the data section and then initialize
754 * all per-vnet storage from that.
756 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size);
757 if (ef->vnet_base == 0) {
758 printf("%s: vnet module space is out of space; "
759 "cannot allocate %d for %s\n",
760 __func__, size, ef->lf.pathname);
763 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size);
764 vnet_data_copy((void *)ef->vnet_base, size);
765 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
774 * Apply the specified protection to the loadable segments of a preloaded linker
778 preload_protect(elf_file_t ef, vm_prot_t prot)
780 #if defined(__aarch64__) || defined(__amd64__)
782 Elf_Phdr *phdr, *phlimit;
787 hdr = (Elf_Ehdr *)ef->address;
788 phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff);
789 phlimit = phdr + hdr->e_phnum;
790 for (; phdr < phlimit; phdr++) {
791 if (phdr->p_type != PT_LOAD)
794 nprot = prot | VM_PROT_READ;
795 if ((phdr->p_flags & PF_W) != 0)
796 nprot |= VM_PROT_WRITE;
797 if ((phdr->p_flags & PF_X) != 0)
798 nprot |= VM_PROT_EXECUTE;
799 error = pmap_change_prot((vm_offset_t)ef->address +
800 phdr->p_vaddr, round_page(phdr->p_memsz), nprot);
812 * Locate the ARM exception/unwind table info for DDB and stack(9) use by
813 * searching for the section header that describes it. There may be no unwind
814 * info, for example in a module containing only data.
817 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr)
821 for (i = 0; i < nhdr; i++) {
822 if (shdr[i].sh_type == SHT_ARM_EXIDX) {
823 lf->exidx_addr = shdr[i].sh_addr + lf->address;
824 lf->exidx_size = shdr[i].sh_size;
831 * Locate the section headers metadata in a preloaded module, then use it to
832 * locate the exception/unwind table in the module. The size of the metadata
833 * block is stored in a uint32 word immediately before the data itself, and a
834 * comment in preload_search_info() says it is safe to rely on that.
837 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr)
843 modinfo = (uint32_t *)preload_search_info(modptr,
844 MODINFO_METADATA | MODINFOMD_SHDR);
845 if (modinfo != NULL) {
846 shdr = (Elf_Shdr *)modinfo;
847 nhdr = modinfo[-1] / sizeof(Elf_Shdr);
848 link_elf_locate_exidx(lf, shdr, nhdr);
855 link_elf_link_preload(linker_class_t cls, const char *filename,
856 linker_file_t *result)
858 Elf_Addr *ctors_addrp;
859 Elf_Size *ctors_sizep;
860 caddr_t modptr, baseptr, sizeptr, dynptr;
867 /* Look to see if we have the file preloaded */
868 modptr = preload_search_by_name(filename);
872 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
873 baseptr = preload_search_info(modptr, MODINFO_ADDR);
874 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
875 dynptr = preload_search_info(modptr,
876 MODINFO_METADATA | MODINFOMD_DYNAMIC);
878 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
879 strcmp(type, "elf module") != 0))
881 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
884 lf = linker_make_file(filename, &link_elf_class);
888 ef = (elf_file_t) lf;
891 ef->address = *(caddr_t *)baseptr;
892 #ifdef SPARSE_MAPPING
895 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
896 ef->dynamic = (Elf_Dyn *)dp;
897 lf->address = ef->address;
898 lf->size = *(size_t *)sizeptr;
900 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
901 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
902 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
903 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
904 if (ctors_addrp != NULL && ctors_sizep != NULL) {
905 lf->ctors_addr = ef->address + *ctors_addrp;
906 lf->ctors_size = *ctors_sizep;
910 link_elf_locate_exidx_preload(lf, modptr);
913 error = parse_dynamic(ef);
915 error = parse_dpcpu(ef);
918 error = parse_vnet(ef);
921 error = preload_protect(ef, VM_PROT_ALL);
923 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
926 link_elf_reloc_local(lf);
932 link_elf_link_preload_finish(linker_file_t lf)
937 ef = (elf_file_t) lf;
938 error = relocate_file(ef);
940 error = preload_protect(ef, VM_PROT_NONE);
943 (void)link_elf_preload_parse_symbols(ef);
945 return (link_elf_link_common_finish(lf));
949 link_elf_load_file(linker_class_t cls, const char* filename,
950 linker_file_t* result)
953 struct thread* td = curthread; /* XXX */
955 caddr_t firstpage, segbase;
959 Elf_Phdr *segs[MAXSEGS];
965 Elf_Addr base_vlimit;
983 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename);
985 error = vn_open(&nd, &flags, 0, NULL);
989 if (nd.ni_vp->v_type != VREG) {
995 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
1003 * Read the elf header from the file.
1005 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
1006 hdr = (Elf_Ehdr *)firstpage;
1007 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
1008 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1010 nbytes = PAGE_SIZE - resid;
1014 if (!IS_ELF(*hdr)) {
1019 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
1020 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
1021 link_elf_error(filename, "Unsupported file layout");
1025 if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
1026 hdr->e_version != EV_CURRENT) {
1027 link_elf_error(filename, "Unsupported file version");
1031 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
1035 if (hdr->e_machine != ELF_TARG_MACH) {
1036 link_elf_error(filename, "Unsupported machine");
1042 * We rely on the program header being in the first page.
1043 * This is not strictly required by the ABI specification, but
1044 * it seems to always true in practice. And, it simplifies
1045 * things considerably.
1047 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
1048 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
1049 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
1050 link_elf_error(filename, "Unreadable program headers");
1053 * Scan the program header entries, and save key information.
1055 * We rely on there being exactly two load segments, text and data,
1058 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
1059 phlimit = phdr + hdr->e_phnum;
1062 while (phdr < phlimit) {
1063 switch (phdr->p_type) {
1065 if (nsegs == MAXSEGS) {
1066 link_elf_error(filename, "Too many sections");
1071 * XXX: We just trust they come in right order ??
1088 if (phdyn == NULL) {
1089 link_elf_error(filename, "Object is not dynamically-linked");
1094 link_elf_error(filename, "No sections");
1100 * Allocate the entire address space of the object, to stake
1101 * out our contiguous region, and to establish the base
1102 * address for relocation.
1104 base_vaddr = trunc_page(segs[0]->p_vaddr);
1105 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
1106 segs[nsegs - 1]->p_memsz);
1107 mapsize = base_vlimit - base_vaddr;
1109 lf = linker_make_file(filename, &link_elf_class);
1115 ef = (elf_file_t) lf;
1116 #ifdef SPARSE_MAPPING
1117 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, mapsize, VM_PROT_ALL,
1118 0, thread0.td_ucred);
1119 if (ef->object == NULL) {
1124 mapbase = (caddr_t)KERNBASE;
1126 mapbase = (caddr_t)vm_map_min(kernel_map);
1129 * Mapping protections are downgraded after relocation processing.
1131 error = vm_map_find(kernel_map, ef->object, 0,
1132 (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE,
1133 VM_PROT_ALL, VM_PROT_ALL, 0);
1135 vm_object_deallocate(ef->object);
1140 mapbase = malloc_exec(mapsize, M_LINKER, M_WAITOK);
1142 ef->address = mapbase;
1145 * Read the text and data sections and zero the bss.
1147 for (i = 0; i < nsegs; i++) {
1148 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1150 #ifdef SPARSE_MAPPING
1152 * Consecutive segments may have different mapping permissions,
1153 * so be strict and verify that their mappings do not overlap.
1155 if (((vm_offset_t)segbase & PAGE_MASK) != 0) {
1160 error = vm_map_wire(kernel_map,
1161 (vm_offset_t)segbase,
1162 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1163 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
1164 if (error != KERN_SUCCESS) {
1170 error = vn_rdwr(UIO_READ, nd.ni_vp,
1171 segbase, segs[i]->p_filesz, segs[i]->p_offset,
1172 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1176 bzero(segbase + segs[i]->p_filesz,
1177 segs[i]->p_memsz - segs[i]->p_filesz);
1180 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
1182 lf->address = ef->address;
1185 error = parse_dynamic(ef);
1188 error = parse_dpcpu(ef);
1192 error = parse_vnet(ef);
1196 link_elf_reloc_local(lf);
1198 VOP_UNLOCK(nd.ni_vp);
1199 error = linker_load_dependencies(lf);
1200 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1203 error = relocate_file(ef);
1207 #ifdef SPARSE_MAPPING
1209 * Downgrade permissions on text segment mappings now that relocation
1210 * processing is complete. Restrict permissions on read-only segments.
1212 for (i = 0; i < nsegs; i++) {
1215 if (segs[i]->p_type != PT_LOAD)
1218 prot = VM_PROT_READ;
1219 if ((segs[i]->p_flags & PF_W) != 0)
1220 prot |= VM_PROT_WRITE;
1221 if ((segs[i]->p_flags & PF_X) != 0)
1222 prot |= VM_PROT_EXECUTE;
1223 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1224 error = vm_map_protect(kernel_map,
1225 (vm_offset_t)segbase,
1226 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1227 prot, 0, VM_MAP_PROTECT_SET_PROT);
1228 if (error != KERN_SUCCESS) {
1236 * Try and load the symbol table if it's present. (you can
1239 nbytes = hdr->e_shnum * hdr->e_shentsize;
1240 if (nbytes == 0 || hdr->e_shoff == 0)
1242 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1243 error = vn_rdwr(UIO_READ, nd.ni_vp,
1244 (caddr_t)shdr, nbytes, hdr->e_shoff,
1245 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1250 /* Read section string table */
1251 shstrindex = hdr->e_shstrndx;
1252 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1253 shdr[shstrindex].sh_size != 0) {
1254 nbytes = shdr[shstrindex].sh_size;
1255 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1256 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1257 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1258 td->td_ucred, NOCRED, &resid, td);
1265 for (i = 0; i < hdr->e_shnum; i++) {
1266 if (shdr[i].sh_type == SHT_SYMTAB) {
1268 symstrindex = shdr[i].sh_link;
1269 } else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1270 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1271 /* Record relocated address and size of .ctors. */
1272 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1273 lf->ctors_size = shdr[i].sh_size;
1276 if (symtabindex < 0 || symstrindex < 0)
1279 symcnt = shdr[symtabindex].sh_size;
1280 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1281 strcnt = shdr[symstrindex].sh_size;
1282 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1284 error = vn_rdwr(UIO_READ, nd.ni_vp,
1285 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1286 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1290 error = vn_rdwr(UIO_READ, nd.ni_vp,
1291 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1292 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1297 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1298 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1299 ef->ddbstrcnt = strcnt;
1300 ef->ddbstrtab = ef->strbase;
1305 link_elf_locate_exidx(lf, shdr, hdr->e_shnum);
1308 error = link_elf_link_common_finish(lf);
1315 VOP_UNLOCK(nd.ni_vp);
1316 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1317 if (error != 0 && lf != NULL)
1318 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1319 free(shdr, M_LINKER);
1320 free(firstpage, M_LINKER);
1321 free(shstrs, M_LINKER);
1327 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1331 KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class,
1332 ("elf_relocaddr: unexpected linker file %p", lf));
1334 ef = (elf_file_t)lf;
1335 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1336 return ((x - ef->pcpu_start) + ef->pcpu_base);
1338 if (x >= ef->vnet_start && x < ef->vnet_stop)
1339 return ((x - ef->vnet_start) + ef->vnet_base);
1345 link_elf_unload_file(linker_file_t file)
1347 elf_file_t ef = (elf_file_t) file;
1349 if (ef->pcpu_base != 0) {
1350 dpcpu_free((void *)ef->pcpu_base,
1351 ef->pcpu_stop - ef->pcpu_start);
1352 elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1355 if (ef->vnet_base != 0) {
1356 vnet_data_free((void *)ef->vnet_base,
1357 ef->vnet_stop - ef->vnet_start);
1358 elf_set_delete(&set_vnet_list, ef->vnet_start);
1362 if (ef->gdb.l_ld != NULL) {
1363 GDB_STATE(RT_DELETE);
1364 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1365 link_elf_delete_gdb(&ef->gdb);
1366 GDB_STATE(RT_CONSISTENT);
1370 /* Notify MD code that a module is being unloaded. */
1371 elf_cpu_unload_file(file);
1373 if (ef->preloaded) {
1374 link_elf_unload_preload(file);
1378 #ifdef SPARSE_MAPPING
1379 if (ef->object != NULL) {
1380 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1381 (vm_offset_t) ef->address
1382 + (ef->object->size << PAGE_SHIFT));
1385 free(ef->address, M_LINKER);
1387 free(ef->symbase, M_LINKER);
1388 free(ef->strbase, M_LINKER);
1389 free(ef->ctftab, M_LINKER);
1390 free(ef->ctfoff, M_LINKER);
1391 free(ef->typoff, M_LINKER);
1395 link_elf_unload_preload(linker_file_t file)
1398 if (file->pathname != NULL)
1399 preload_delete_name(file->pathname);
1403 symbol_name(elf_file_t ef, Elf_Size r_info)
1407 if (ELF_R_SYM(r_info)) {
1408 ref = ef->symtab + ELF_R_SYM(r_info);
1409 return (ef->strtab + ref->st_name);
1415 symbol_type(elf_file_t ef, Elf_Size r_info)
1419 if (ELF_R_SYM(r_info)) {
1420 ref = ef->symtab + ELF_R_SYM(r_info);
1421 return (ELF_ST_TYPE(ref->st_info));
1423 return (STT_NOTYPE);
1427 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc,
1431 const Elf_Rela *rela;
1432 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 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA);
1453 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL);
1454 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA);
1462 relocate_file(elf_file_t ef)
1466 error = relocate_file1(ef, elf_lookup, elf_reloc, false);
1468 error = relocate_file1(ef, elf_lookup, elf_reloc, true);
1473 * Hash function for symbol table lookup. Don't even think about changing
1474 * this. It is specified by the System V ABI.
1476 static unsigned long
1477 elf_hash(const char *name)
1479 const unsigned char *p = (const unsigned char *) name;
1480 unsigned long h = 0;
1483 while (*p != '\0') {
1484 h = (h << 4) + *p++;
1485 if ((g = h & 0xf0000000) != 0)
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;
1958 bzero_early(ef, sizeof(*ef));
1961 ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
1963 #ifdef RELOCATABLE_KERNEL
1964 ef->address = (caddr_t) (__startkernel - KERNBASE);
1970 link_elf_preload_parse_symbols(ef);
1971 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true);
1974 #if defined(__aarch64__) || defined(__amd64__)
1976 link_elf_late_ireloc(void)
1980 KASSERT(linker_kernel_file != NULL,
1981 ("link_elf_late_ireloc: No kernel linker file found"));
1982 ef = (elf_file_t)linker_kernel_file;
1984 relocate_file1(ef, elf_lookup_ifunc, elf_reloc_late, true);