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77b793c465
freebsd/sys/kern/link_elf.c
Konstantin Belousov fbf2a77876 Convert allocations of the phys pager to vm_pager_allocate(). 
Future changes would require additional initialization of OBJT_PHYS
objects, and vm_object_allocate() is not suitable for it.

Reviewed by:	markj
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D24652
2020-09-08 23:38:49 +00:00

1943 lines
48 KiB
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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 1998-2000 Doug Rabson
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ddb.h"
#include "opt_gdb.h"
#include <sys/param.h>
#include <sys/systm.h>
#ifdef GPROF
#include <sys/gmon.h>
#endif
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#ifdef SPARSE_MAPPING
#include <sys/mman.h>
#endif
#include <sys/mutex.h>
#include <sys/mount.h>
#include <sys/pcpu.h>
#include <sys/proc.h>
#include <sys/namei.h>
#include <sys/fcntl.h>
#include <sys/vnode.h>
#include <sys/linker.h>
#include <sys/sysctl.h>
#include <machine/elf.h>
#include <net/vnet.h>
#include <security/mac/mac_framework.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#ifdef SPARSE_MAPPING
#include <vm/vm_object.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#endif
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <sys/link_elf.h>
#include "linker_if.h"
#define MAXSEGS 4
typedef struct elf_file {
struct linker_file lf; /* Common fields */
int preloaded; /* Was file pre-loaded */
caddr_t address; /* Relocation address */
#ifdef SPARSE_MAPPING
vm_object_t object; /* VM object to hold file pages */
#endif
Elf_Dyn *dynamic; /* Symbol table etc. */
Elf_Hashelt nbuckets; /* DT_HASH info */
Elf_Hashelt nchains;
const Elf_Hashelt *buckets;
const Elf_Hashelt *chains;
caddr_t hash;
caddr_t strtab; /* DT_STRTAB */
int strsz; /* DT_STRSZ */
const Elf_Sym *symtab; /* DT_SYMTAB */
Elf_Addr *got; /* DT_PLTGOT */
const Elf_Rel *pltrel; /* DT_JMPREL */
int pltrelsize; /* DT_PLTRELSZ */
const Elf_Rela *pltrela; /* DT_JMPREL */
int pltrelasize; /* DT_PLTRELSZ */
const Elf_Rel *rel; /* DT_REL */
int relsize; /* DT_RELSZ */
const Elf_Rela *rela; /* DT_RELA */
int relasize; /* DT_RELASZ */
caddr_t modptr;
const Elf_Sym *ddbsymtab; /* The symbol table we are using */
long ddbsymcnt; /* Number of symbols */
caddr_t ddbstrtab; /* String table */
long ddbstrcnt; /* number of bytes in string table */
caddr_t symbase; /* malloc'ed symbold base */
caddr_t strbase; /* malloc'ed string base */
caddr_t ctftab; /* CTF table */
long ctfcnt; /* number of bytes in CTF table */
caddr_t ctfoff; /* CTF offset table */
caddr_t typoff; /* Type offset table */
long typlen; /* Number of type entries. */
Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */
Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */
Elf_Addr pcpu_base; /* Relocated pcpu set address. */
#ifdef VIMAGE
Elf_Addr vnet_start; /* Pre-relocation vnet set start. */
Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */
Elf_Addr vnet_base; /* Relocated vnet set address. */
#endif
#ifdef GDB
struct link_map gdb; /* hooks for gdb */
#endif
} *elf_file_t;
struct elf_set {
Elf_Addr es_start;
Elf_Addr es_stop;
Elf_Addr es_base;
TAILQ_ENTRY(elf_set) es_link;
};
TAILQ_HEAD(elf_set_head, elf_set);
#include <kern/kern_ctf.c>
static int link_elf_link_common_finish(linker_file_t);
static int link_elf_link_preload(linker_class_t cls,
const char *, linker_file_t *);
static int link_elf_link_preload_finish(linker_file_t);
static int link_elf_load_file(linker_class_t, const char *,
linker_file_t *);
static int link_elf_lookup_symbol(linker_file_t, const char *,
c_linker_sym_t *);
static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
linker_symval_t *);
static int link_elf_search_symbol(linker_file_t, caddr_t,
c_linker_sym_t *, long *);
static void link_elf_unload_file(linker_file_t);
static void link_elf_unload_preload(linker_file_t);
static int link_elf_lookup_set(linker_file_t, const char *,
void ***, void ***, int *);
static int link_elf_each_function_name(linker_file_t,
int (*)(const char *, void *), void *);
static int link_elf_each_function_nameval(linker_file_t,
linker_function_nameval_callback_t, void *);
static void link_elf_reloc_local(linker_file_t);
static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
static long link_elf_strtab_get(linker_file_t, caddr_t *);
static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
static kobj_method_t link_elf_methods[] = {
KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
KOBJMETHOD(linker_unload, link_elf_unload_file),
KOBJMETHOD(linker_load_file, link_elf_load_file),
KOBJMETHOD(linker_link_preload, link_elf_link_preload),
KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
KOBJMETHOD_END
};
static struct linker_class link_elf_class = {
#if ELF_TARG_CLASS == ELFCLASS32
"elf32",
#else
"elf64",
#endif
link_elf_methods, sizeof(struct elf_file)
};
typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase,
const void *data, int type, elf_lookup_fn lookup);
static int parse_dynamic(elf_file_t);
static int relocate_file(elf_file_t);
static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup,
elf_reloc_fn reloc, bool ifuncs);
static int link_elf_preload_parse_symbols(elf_file_t);
static struct elf_set_head set_pcpu_list;
#ifdef VIMAGE
static struct elf_set_head set_vnet_list;
#endif
static void
elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
{
struct elf_set *set, *iter;
set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
set->es_start = start;
set->es_stop = stop;
set->es_base = base;
TAILQ_FOREACH(iter, list, es_link) {
KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
(set->es_start > iter->es_start && set->es_stop > iter->es_stop),
("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
(uintmax_t)set->es_start, (uintmax_t)set->es_stop,
(uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
if (iter->es_start > set->es_start) {
TAILQ_INSERT_BEFORE(iter, set, es_link);
break;
}
}
if (iter == NULL)
TAILQ_INSERT_TAIL(list, set, es_link);
}
static int
elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
{
struct elf_set *set;
TAILQ_FOREACH(set, list, es_link) {
if (addr < set->es_start)
return (0);
if (addr < set->es_stop) {
*start = set->es_start;
*base = set->es_base;
return (1);
}
}
return (0);
}
static void
elf_set_delete(struct elf_set_head *list, Elf_Addr start)
{
struct elf_set *set;
TAILQ_FOREACH(set, list, es_link) {
if (start < set->es_start)
break;
if (start == set->es_start) {
TAILQ_REMOVE(list, set, es_link);
free(set, M_LINKER);
return;
}
}
KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
(uintmax_t)start));
}
#ifdef GDB
static void r_debug_state(struct r_debug *, struct link_map *);
/*
* A list of loaded modules for GDB to use for loading symbols.
*/
struct r_debug r_debug;
#define GDB_STATE(s) do { \
r_debug.r_state = s; r_debug_state(NULL, NULL); \
} while (0)
/*
* Function for the debugger to set a breakpoint on to gain control.
*/
static void
r_debug_state(struct r_debug *dummy_one __unused,
struct link_map *dummy_two __unused)
{
}
static void
link_elf_add_gdb(struct link_map *l)
{
struct link_map *prev;
l->l_next = NULL;
if (r_debug.r_map == NULL) {
/* Add first. */
l->l_prev = NULL;
r_debug.r_map = l;
} else {
/* Append to list. */
for (prev = r_debug.r_map;
prev->l_next != NULL;
prev = prev->l_next)
;
l->l_prev = prev;
prev->l_next = l;
}
}
static void
link_elf_delete_gdb(struct link_map *l)
{
if (l->l_prev == NULL) {
/* Remove first. */
if ((r_debug.r_map = l->l_next) != NULL)
l->l_next->l_prev = NULL;
} else {
/* Remove any but first. */
if ((l->l_prev->l_next = l->l_next) != NULL)
l->l_next->l_prev = l->l_prev;
}
}
#endif /* GDB */
/*
* The kernel symbol table starts here.
*/
extern struct _dynamic _DYNAMIC;
static void
link_elf_error(const char *filename, const char *s)
{
if (filename == NULL)
printf("kldload: %s\n", s);
else
printf("kldload: %s: %s\n", filename, s);
}
static void
link_elf_invoke_ctors(caddr_t addr, size_t size)
{
void (**ctor)(void);
size_t i, cnt;
if (addr == NULL || size == 0)
return;
cnt = size / sizeof(*ctor);
ctor = (void *)addr;
for (i = 0; i < cnt; i++) {
if (ctor[i] != NULL)
(*ctor[i])();
}
}
/*
* Actions performed after linking/loading both the preloaded kernel and any
* modules; whether preloaded or dynamicly loaded.
*/
static int
link_elf_link_common_finish(linker_file_t lf)
{
#ifdef GDB
elf_file_t ef = (elf_file_t)lf;
char *newfilename;
#endif
int error;
/* Notify MD code that a module is being loaded. */
error = elf_cpu_load_file(lf);
if (error != 0)
return (error);
#ifdef GDB
GDB_STATE(RT_ADD);
ef->gdb.l_addr = lf->address;
newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
strcpy(newfilename, lf->filename);
ef->gdb.l_name = newfilename;
ef->gdb.l_ld = ef->dynamic;
link_elf_add_gdb(&ef->gdb);
GDB_STATE(RT_CONSISTENT);
#endif
/* Invoke .ctors */
link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
return (0);
}
#ifdef RELOCATABLE_KERNEL
/*
* __startkernel and __endkernel are symbols set up as relocation canaries.
*
* They are defined in locore to reference linker script symbols at the
* beginning and end of the LOAD area. This has the desired side effect of
* giving us variables that have relative relocations pointing at them, so
* relocation of the kernel object will cause the variables to be updated
* automatically by the runtime linker when we initialize.
*
* There are two main reasons to relocate the kernel:
* 1) If the loader needed to load the kernel at an alternate load address.
* 2) If the kernel is switching address spaces on machines like POWER9
* under Radix where the high bits of the effective address are used to
* differentiate between hypervisor, host, guest, and problem state.
*/
extern vm_offset_t __startkernel, __endkernel;
#endif
static unsigned long kern_relbase = KERNBASE;
SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD,
SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address");
SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD,
&kern_relbase, 0, "Kernel relocated base address");
static void
link_elf_init(void* arg)
{
Elf_Dyn *dp;
Elf_Addr *ctors_addrp;
Elf_Size *ctors_sizep;
caddr_t modptr, baseptr, sizeptr;
elf_file_t ef;
const char *modname;
linker_add_class(&link_elf_class);
dp = (Elf_Dyn *)&_DYNAMIC;
modname = NULL;
modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
if (modptr == NULL)
modptr = preload_search_by_type("elf kernel");
modname = (char *)preload_search_info(modptr, MODINFO_NAME);
if (modname == NULL)
modname = "kernel";
linker_kernel_file = linker_make_file(modname, &link_elf_class);
if (linker_kernel_file == NULL)
panic("%s: Can't create linker structures for kernel",
__func__);
ef = (elf_file_t) linker_kernel_file;
ef->preloaded = 1;
#ifdef RELOCATABLE_KERNEL
/* Compute relative displacement */
ef->address = (caddr_t) (__startkernel - KERNBASE);
#else
ef->address = 0;
#endif
#ifdef SPARSE_MAPPING
ef->object = NULL;
#endif
ef->dynamic = dp;
if (dp != NULL)
parse_dynamic(ef);
#ifdef RELOCATABLE_KERNEL
linker_kernel_file->address = (caddr_t)__startkernel;
linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
kern_relbase = (unsigned long)__startkernel;
#else
linker_kernel_file->address += KERNBASE;
linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
#endif
if (modptr != NULL) {
ef->modptr = modptr;
baseptr = preload_search_info(modptr, MODINFO_ADDR);
if (baseptr != NULL)
linker_kernel_file->address = *(caddr_t *)baseptr;
sizeptr = preload_search_info(modptr, MODINFO_SIZE);
if (sizeptr != NULL)
linker_kernel_file->size = *(size_t *)sizeptr;
ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
ctors_sizep = (Elf_Size *)preload_search_info(modptr,
MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
if (ctors_addrp != NULL && ctors_sizep != NULL) {
linker_kernel_file->ctors_addr = ef->address +
*ctors_addrp;
linker_kernel_file->ctors_size = *ctors_sizep;
}
}
(void)link_elf_preload_parse_symbols(ef);
#ifdef GDB
r_debug.r_map = NULL;
r_debug.r_brk = r_debug_state;
r_debug.r_state = RT_CONSISTENT;
#endif
(void)link_elf_link_common_finish(linker_kernel_file);
linker_kernel_file->flags |= LINKER_FILE_LINKED;
TAILQ_INIT(&set_pcpu_list);
#ifdef VIMAGE
TAILQ_INIT(&set_vnet_list);
#endif
}
SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL);
static int
link_elf_preload_parse_symbols(elf_file_t ef)
{
caddr_t pointer;
caddr_t ssym, esym, base;
caddr_t strtab;
int strcnt;
Elf_Sym *symtab;
int symcnt;
if (ef->modptr == NULL)
return (0);
pointer = preload_search_info(ef->modptr,
MODINFO_METADATA | MODINFOMD_SSYM);
if (pointer == NULL)
return (0);
ssym = *(caddr_t *)pointer;
pointer = preload_search_info(ef->modptr,
MODINFO_METADATA | MODINFOMD_ESYM);
if (pointer == NULL)
return (0);
esym = *(caddr_t *)pointer;
base = ssym;
symcnt = *(long *)base;
base += sizeof(long);
symtab = (Elf_Sym *)base;
base += roundup(symcnt, sizeof(long));
if (base > esym || base < ssym) {
printf("Symbols are corrupt!\n");
return (EINVAL);
}
strcnt = *(long *)base;
base += sizeof(long);
strtab = base;
base += roundup(strcnt, sizeof(long));
if (base > esym || base < ssym) {
printf("Symbols are corrupt!\n");
return (EINVAL);
}
ef->ddbsymtab = symtab;
ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
ef->ddbstrtab = strtab;
ef->ddbstrcnt = strcnt;
return (0);
}
static int
parse_dynamic(elf_file_t ef)
{
Elf_Dyn *dp;
int plttype = DT_REL;
for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
switch (dp->d_tag) {
case DT_HASH:
{
/* From src/libexec/rtld-elf/rtld.c */
const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
(ef->address + dp->d_un.d_ptr);
ef->nbuckets = hashtab[0];
ef->nchains = hashtab[1];
ef->buckets = hashtab + 2;
ef->chains = ef->buckets + ef->nbuckets;
break;
}
case DT_STRTAB:
ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
break;
case DT_STRSZ:
ef->strsz = dp->d_un.d_val;
break;
case DT_SYMTAB:
ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
break;
case DT_SYMENT:
if (dp->d_un.d_val != sizeof(Elf_Sym))
return (ENOEXEC);
break;
case DT_PLTGOT:
ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
break;
case DT_REL:
ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
break;
case DT_RELSZ:
ef->relsize = dp->d_un.d_val;
break;
case DT_RELENT:
if (dp->d_un.d_val != sizeof(Elf_Rel))
return (ENOEXEC);
break;
case DT_JMPREL:
ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
break;
case DT_PLTRELSZ:
ef->pltrelsize = dp->d_un.d_val;
break;
case DT_RELA:
ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
break;
case DT_RELASZ:
ef->relasize = dp->d_un.d_val;
break;
case DT_RELAENT:
if (dp->d_un.d_val != sizeof(Elf_Rela))
return (ENOEXEC);
break;
case DT_PLTREL:
plttype = dp->d_un.d_val;
if (plttype != DT_REL && plttype != DT_RELA)
return (ENOEXEC);
break;
#ifdef GDB
case DT_DEBUG:
dp->d_un.d_ptr = (Elf_Addr)&r_debug;
break;
#endif
}
}
if (plttype == DT_RELA) {
ef->pltrela = (const Elf_Rela *)ef->pltrel;
ef->pltrel = NULL;
ef->pltrelasize = ef->pltrelsize;
ef->pltrelsize = 0;
}
ef->ddbsymtab = ef->symtab;
ef->ddbsymcnt = ef->nchains;
ef->ddbstrtab = ef->strtab;
ef->ddbstrcnt = ef->strsz;
return elf_cpu_parse_dynamic(ef->address, ef->dynamic);
}
#define LS_PADDING 0x90909090
static int
parse_dpcpu(elf_file_t ef)
{
int error, size;
#if defined(__i386__)
uint32_t pad;
#endif
ef->pcpu_start = 0;
ef->pcpu_stop = 0;
error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
(void ***)&ef->pcpu_stop, NULL);
/* Error just means there is no pcpu set to relocate. */
if (error != 0)
return (0);
size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start;
/* Empty set? */
if (size < 1)
return (0);
#if defined(__i386__)
/* In case we do find __start/stop_set_ symbols double-check. */
if (size < 4) {
uprintf("Kernel module '%s' must be recompiled with "
"linker script\n", ef->lf.pathname);
return (ENOEXEC);
}
/* Padding from linker-script correct? */
pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad));
if (pad != LS_PADDING) {
uprintf("Kernel module '%s' must be recompiled with "
"linker script, invalid padding %#04x (%#04x)\n",
ef->lf.pathname, pad, LS_PADDING);
return (ENOEXEC);
}
/* If we only have valid padding, nothing to do. */
if (size == 4)
return (0);
#endif
/*
* Allocate space in the primary pcpu area. Copy in our
* initialization from the data section and then initialize
* all per-cpu storage from that.
*/
ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size);
if (ef->pcpu_base == 0) {
printf("%s: pcpu module space is out of space; "
"cannot allocate %d for %s\n",
__func__, size, ef->lf.pathname);
return (ENOSPC);
}
memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size);
dpcpu_copy((void *)ef->pcpu_base, size);
elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
ef->pcpu_base);
return (0);
}
#ifdef VIMAGE
static int
parse_vnet(elf_file_t ef)
{
int error, size;
#if defined(__i386__)
uint32_t pad;
#endif
ef->vnet_start = 0;
ef->vnet_stop = 0;
error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
(void ***)&ef->vnet_stop, NULL);
/* Error just means there is no vnet data set to relocate. */
if (error != 0)
return (0);
size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
/* Empty set? */
if (size < 1)
return (0);
#if defined(__i386__)
/* In case we do find __start/stop_set_ symbols double-check. */
if (size < 4) {
uprintf("Kernel module '%s' must be recompiled with "
"linker script\n", ef->lf.pathname);
return (ENOEXEC);
}
/* Padding from linker-script correct? */
pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad));
if (pad != LS_PADDING) {
uprintf("Kernel module '%s' must be recompiled with "
"linker script, invalid padding %#04x (%#04x)\n",
ef->lf.pathname, pad, LS_PADDING);
return (ENOEXEC);
}
/* If we only have valid padding, nothing to do. */
if (size == 4)
return (0);
#endif
/*
* Allocate space in the primary vnet area. Copy in our
* initialization from the data section and then initialize
* all per-vnet storage from that.
*/
ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size);
if (ef->vnet_base == 0) {
printf("%s: vnet module space is out of space; "
"cannot allocate %d for %s\n",
__func__, size, ef->lf.pathname);
return (ENOSPC);
}
memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size);
vnet_data_copy((void *)ef->vnet_base, size);
elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
ef->vnet_base);
return (0);
}
#endif
#undef LS_PADDING
/*
* Apply the specified protection to the loadable segments of a preloaded linker
* file.
*/
static int
preload_protect(elf_file_t ef, vm_prot_t prot)
{
#ifdef __amd64__
Elf_Ehdr *hdr;
Elf_Phdr *phdr, *phlimit;
vm_prot_t nprot;
int error;
error = 0;
hdr = (Elf_Ehdr *)ef->address;
phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff);
phlimit = phdr + hdr->e_phnum;
for (; phdr < phlimit; phdr++) {
if (phdr->p_type != PT_LOAD)
continue;
nprot = prot | VM_PROT_READ;
if ((phdr->p_flags & PF_W) != 0)
nprot |= VM_PROT_WRITE;
if ((phdr->p_flags & PF_X) != 0)
nprot |= VM_PROT_EXECUTE;
error = pmap_change_prot((vm_offset_t)ef->address +
phdr->p_vaddr, round_page(phdr->p_memsz), nprot);
if (error != 0)
break;
}
return (error);
#else
return (0);
#endif
}
#ifdef __arm__
/*
* Locate the ARM exception/unwind table info for DDB and stack(9) use by
* searching for the section header that describes it. There may be no unwind
* info, for example in a module containing only data.
*/
static void
link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr)
{
int i;
for (i = 0; i < nhdr; i++) {
if (shdr[i].sh_type == SHT_ARM_EXIDX) {
lf->exidx_addr = shdr[i].sh_addr + lf->address;
lf->exidx_size = shdr[i].sh_size;
break;
}
}
}
/*
* Locate the section headers metadata in a preloaded module, then use it to
* locate the exception/unwind table in the module. The size of the metadata
* block is stored in a uint32 word immediately before the data itself, and a
* comment in preload_search_info() says it is safe to rely on that.
*/
static void
link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr)
{
uint32_t *modinfo;
Elf_Shdr *shdr;
uint32_t nhdr;
modinfo = (uint32_t *)preload_search_info(modptr,
MODINFO_METADATA | MODINFOMD_SHDR);
if (modinfo != NULL) {
shdr = (Elf_Shdr *)modinfo;
nhdr = modinfo[-1] / sizeof(Elf_Shdr);
link_elf_locate_exidx(lf, shdr, nhdr);
}
}
#endif /* __arm__ */
static int
link_elf_link_preload(linker_class_t cls, const char *filename,
linker_file_t *result)
{
Elf_Addr *ctors_addrp;
Elf_Size *ctors_sizep;
caddr_t modptr, baseptr, sizeptr, dynptr;
char *type;
elf_file_t ef;
linker_file_t lf;
int error;
vm_offset_t dp;
/* Look to see if we have the file preloaded */
modptr = preload_search_by_name(filename);
if (modptr == NULL)
return (ENOENT);
type = (char *)preload_search_info(modptr, MODINFO_TYPE);
baseptr = preload_search_info(modptr, MODINFO_ADDR);
sizeptr = preload_search_info(modptr, MODINFO_SIZE);
dynptr = preload_search_info(modptr,
MODINFO_METADATA | MODINFOMD_DYNAMIC);
if (type == NULL ||
(strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
strcmp(type, "elf module") != 0))
return (EFTYPE);
if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
return (EINVAL);
lf = linker_make_file(filename, &link_elf_class);
if (lf == NULL)
return (ENOMEM);
ef = (elf_file_t) lf;
ef->preloaded = 1;
ef->modptr = modptr;
ef->address = *(caddr_t *)baseptr;
#ifdef SPARSE_MAPPING
ef->object = NULL;
#endif
dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
ef->dynamic = (Elf_Dyn *)dp;
lf->address = ef->address;
lf->size = *(size_t *)sizeptr;
ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
ctors_sizep = (Elf_Size *)preload_search_info(modptr,
MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
if (ctors_addrp != NULL && ctors_sizep != NULL) {
lf->ctors_addr = ef->address + *ctors_addrp;
lf->ctors_size = *ctors_sizep;
}
#ifdef __arm__
link_elf_locate_exidx_preload(lf, modptr);
#endif
error = parse_dynamic(ef);
if (error == 0)
error = parse_dpcpu(ef);
#ifdef VIMAGE
if (error == 0)
error = parse_vnet(ef);
#endif
if (error == 0)
error = preload_protect(ef, VM_PROT_ALL);
if (error != 0) {
linker_file_unload(lf, LINKER_UNLOAD_FORCE);
return (error);
}
link_elf_reloc_local(lf);
*result = lf;
return (0);
}
static int
link_elf_link_preload_finish(linker_file_t lf)
{
elf_file_t ef;
int error;
ef = (elf_file_t) lf;
error = relocate_file(ef);
if (error == 0)
error = preload_protect(ef, VM_PROT_NONE);
if (error != 0)
return (error);
(void)link_elf_preload_parse_symbols(ef);
return (link_elf_link_common_finish(lf));
}
static int
link_elf_load_file(linker_class_t cls, const char* filename,
linker_file_t* result)
{
struct nameidata nd;
struct thread* td = curthread; /* XXX */
Elf_Ehdr *hdr;
caddr_t firstpage, segbase;
int nbytes, i;
Elf_Phdr *phdr;
Elf_Phdr *phlimit;
Elf_Phdr *segs[MAXSEGS];
int nsegs;
Elf_Phdr *phdyn;
caddr_t mapbase;
size_t mapsize;
Elf_Addr base_vaddr;
Elf_Addr base_vlimit;
int error = 0;
ssize_t resid;
int flags;
elf_file_t ef;
linker_file_t lf;
Elf_Shdr *shdr;
int symtabindex;
int symstrindex;
int shstrindex;
int symcnt;
int strcnt;
char *shstrs;
shdr = NULL;
lf = NULL;
shstrs = NULL;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
flags = FREAD;
error = vn_open(&nd, &flags, 0, NULL);
if (error != 0)
return (error);
NDFREE(&nd, NDF_ONLY_PNBUF);
if (nd.ni_vp->v_type != VREG) {
error = ENOEXEC;
firstpage = NULL;
goto out;
}
#ifdef MAC
error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
if (error != 0) {
firstpage = NULL;
goto out;
}
#endif
/*
* Read the elf header from the file.
*/
firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
hdr = (Elf_Ehdr *)firstpage;
error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
nbytes = PAGE_SIZE - resid;
if (error != 0)
goto out;
if (!IS_ELF(*hdr)) {
error = ENOEXEC;
goto out;
}
if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
link_elf_error(filename, "Unsupported file layout");
error = ENOEXEC;
goto out;
}
if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
hdr->e_version != EV_CURRENT) {
link_elf_error(filename, "Unsupported file version");
error = ENOEXEC;
goto out;
}
if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
error = ENOSYS;
goto out;
}
if (hdr->e_machine != ELF_TARG_MACH) {
link_elf_error(filename, "Unsupported machine");
error = ENOEXEC;
goto out;
}
/*
* We rely on the program header being in the first page.
* This is not strictly required by the ABI specification, but
* it seems to always true in practice. And, it simplifies
* things considerably.
*/
if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
(hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
(hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
link_elf_error(filename, "Unreadable program headers");
/*
* Scan the program header entries, and save key information.
*
* We rely on there being exactly two load segments, text and data,
* in that order.
*/
phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
phlimit = phdr + hdr->e_phnum;
nsegs = 0;
phdyn = NULL;
while (phdr < phlimit) {
switch (phdr->p_type) {
case PT_LOAD:
if (nsegs == MAXSEGS) {
link_elf_error(filename, "Too many sections");
error = ENOEXEC;
goto out;
}
/*
* XXX: We just trust they come in right order ??
*/
segs[nsegs] = phdr;
++nsegs;
break;
case PT_DYNAMIC:
phdyn = phdr;
break;
case PT_INTERP:
error = ENOSYS;
goto out;
}
++phdr;
}
if (phdyn == NULL) {
link_elf_error(filename, "Object is not dynamically-linked");
error = ENOEXEC;
goto out;
}
if (nsegs == 0) {
link_elf_error(filename, "No sections");
error = ENOEXEC;
goto out;
}
/*
* Allocate the entire address space of the object, to stake
* out our contiguous region, and to establish the base
* address for relocation.
*/
base_vaddr = trunc_page(segs[0]->p_vaddr);
base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
segs[nsegs - 1]->p_memsz);
mapsize = base_vlimit - base_vaddr;
lf = linker_make_file(filename, &link_elf_class);
if (lf == NULL) {
error = ENOMEM;
goto out;
}
ef = (elf_file_t) lf;
#ifdef SPARSE_MAPPING
ef->object = vm_pager_allocate(OBJT_PHYS, NULL, mapsize, VM_PROT_ALL,
0, thread0.td_ucred);
if (ef->object == NULL) {
error = ENOMEM;
goto out;
}
#ifdef __amd64__
mapbase = (caddr_t)KERNBASE;
#else
mapbase = (caddr_t)vm_map_min(kernel_map);
#endif
/*
* Mapping protections are downgraded after relocation processing.
*/
error = vm_map_find(kernel_map, ef->object, 0,
(vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE,
VM_PROT_ALL, VM_PROT_ALL, 0);
if (error != 0) {
vm_object_deallocate(ef->object);
ef->object = NULL;
goto out;
}
#else
mapbase = malloc(mapsize, M_LINKER, M_EXEC | M_WAITOK);
#endif
ef->address = mapbase;
/*
* Read the text and data sections and zero the bss.
*/
for (i = 0; i < nsegs; i++) {
segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
#ifdef SPARSE_MAPPING
/*
* Consecutive segments may have different mapping permissions,
* so be strict and verify that their mappings do not overlap.
*/
if (((vm_offset_t)segbase & PAGE_MASK) != 0) {
error = EINVAL;
goto out;
}
error = vm_map_wire(kernel_map,
(vm_offset_t)segbase,
(vm_offset_t)segbase + round_page(segs[i]->p_memsz),
VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
if (error != KERN_SUCCESS) {
error = ENOMEM;
goto out;
}
#endif
error = vn_rdwr(UIO_READ, nd.ni_vp,
segbase, segs[i]->p_filesz, segs[i]->p_offset,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
if (error != 0)
goto out;
bzero(segbase + segs[i]->p_filesz,
segs[i]->p_memsz - segs[i]->p_filesz);
}
#ifdef GPROF
/* Update profiling information with the new text segment. */
mtx_lock(&Giant);
kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
segs[0]->p_memsz));
mtx_unlock(&Giant);
#endif
ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
lf->address = ef->address;
lf->size = mapsize;
error = parse_dynamic(ef);
if (error != 0)
goto out;
error = parse_dpcpu(ef);
if (error != 0)
goto out;
#ifdef VIMAGE
error = parse_vnet(ef);
if (error != 0)
goto out;
#endif
link_elf_reloc_local(lf);
VOP_UNLOCK(nd.ni_vp);
error = linker_load_dependencies(lf);
vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
if (error != 0)
goto out;
error = relocate_file(ef);
if (error != 0)
goto out;
#ifdef SPARSE_MAPPING
/*
* Downgrade permissions on text segment mappings now that relocation
* processing is complete. Restrict permissions on read-only segments.
*/
for (i = 0; i < nsegs; i++) {
vm_prot_t prot;
if (segs[i]->p_type != PT_LOAD)
continue;
prot = VM_PROT_READ;
if ((segs[i]->p_flags & PF_W) != 0)
prot |= VM_PROT_WRITE;
if ((segs[i]->p_flags & PF_X) != 0)
prot |= VM_PROT_EXECUTE;
segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
error = vm_map_protect(kernel_map,
(vm_offset_t)segbase,
(vm_offset_t)segbase + round_page(segs[i]->p_memsz),
prot, FALSE);
if (error != KERN_SUCCESS) {
error = ENOMEM;
goto out;
}
}
#endif
/*
* Try and load the symbol table if it's present. (you can
* strip it!)
*/
nbytes = hdr->e_shnum * hdr->e_shentsize;
if (nbytes == 0 || hdr->e_shoff == 0)
goto nosyms;
shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
error = vn_rdwr(UIO_READ, nd.ni_vp,
(caddr_t)shdr, nbytes, hdr->e_shoff,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
if (error != 0)
goto out;
/* Read section string table */
shstrindex = hdr->e_shstrndx;
if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
shdr[shstrindex].sh_size != 0) {
nbytes = shdr[shstrindex].sh_size;
shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
td->td_ucred, NOCRED, &resid, td);
if (error)
goto out;
}
symtabindex = -1;
symstrindex = -1;
for (i = 0; i < hdr->e_shnum; i++) {
if (shdr[i].sh_type == SHT_SYMTAB) {
symtabindex = i;
symstrindex = shdr[i].sh_link;
} else if (shstrs != NULL && shdr[i].sh_name != 0 &&
strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
/* Record relocated address and size of .ctors. */
lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
lf->ctors_size = shdr[i].sh_size;
}
}
if (symtabindex < 0 || symstrindex < 0)
goto nosyms;
symcnt = shdr[symtabindex].sh_size;
ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
strcnt = shdr[symstrindex].sh_size;
ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
error = vn_rdwr(UIO_READ, nd.ni_vp,
ef->symbase, symcnt, shdr[symtabindex].sh_offset,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
if (error != 0)
goto out;
error = vn_rdwr(UIO_READ, nd.ni_vp,
ef->strbase, strcnt, shdr[symstrindex].sh_offset,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
if (error != 0)
goto out;
ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
ef->ddbstrcnt = strcnt;
ef->ddbstrtab = ef->strbase;
nosyms:
#ifdef __arm__
link_elf_locate_exidx(lf, shdr, hdr->e_shnum);
#endif
error = link_elf_link_common_finish(lf);
if (error != 0)
goto out;
*result = lf;
out:
VOP_UNLOCK(nd.ni_vp);
vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
if (error != 0 && lf != NULL)
linker_file_unload(lf, LINKER_UNLOAD_FORCE);
free(shdr, M_LINKER);
free(firstpage, M_LINKER);
free(shstrs, M_LINKER);
return (error);
}
Elf_Addr
elf_relocaddr(linker_file_t lf, Elf_Addr x)
{
elf_file_t ef;
KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class,
("elf_relocaddr: unexpected linker file %p", lf));
ef = (elf_file_t)lf;
if (x >= ef->pcpu_start && x < ef->pcpu_stop)
return ((x - ef->pcpu_start) + ef->pcpu_base);
#ifdef VIMAGE
if (x >= ef->vnet_start && x < ef->vnet_stop)
return ((x - ef->vnet_start) + ef->vnet_base);
#endif
return (x);
}
static void
link_elf_unload_file(linker_file_t file)
{
elf_file_t ef = (elf_file_t) file;
if (ef->pcpu_base != 0) {
dpcpu_free((void *)ef->pcpu_base,
ef->pcpu_stop - ef->pcpu_start);
elf_set_delete(&set_pcpu_list, ef->pcpu_start);
}
#ifdef VIMAGE
if (ef->vnet_base != 0) {
vnet_data_free((void *)ef->vnet_base,
ef->vnet_stop - ef->vnet_start);
elf_set_delete(&set_vnet_list, ef->vnet_start);
}
#endif
#ifdef GDB
if (ef->gdb.l_ld != NULL) {
GDB_STATE(RT_DELETE);
free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
link_elf_delete_gdb(&ef->gdb);
GDB_STATE(RT_CONSISTENT);
}
#endif
/* Notify MD code that a module is being unloaded. */
elf_cpu_unload_file(file);
if (ef->preloaded) {
link_elf_unload_preload(file);
return;
}
#ifdef SPARSE_MAPPING
if (ef->object != NULL) {
vm_map_remove(kernel_map, (vm_offset_t) ef->address,
(vm_offset_t) ef->address
+ (ef->object->size << PAGE_SHIFT));
}
#else
free(ef->address, M_LINKER);
#endif
free(ef->symbase, M_LINKER);
free(ef->strbase, M_LINKER);
free(ef->ctftab, M_LINKER);
free(ef->ctfoff, M_LINKER);
free(ef->typoff, M_LINKER);
}
static void
link_elf_unload_preload(linker_file_t file)
{
if (file->pathname != NULL)
preload_delete_name(file->pathname);
}
static const char *
symbol_name(elf_file_t ef, Elf_Size r_info)
{
const Elf_Sym *ref;
if (ELF_R_SYM(r_info)) {
ref = ef->symtab + ELF_R_SYM(r_info);
return (ef->strtab + ref->st_name);
}
return (NULL);
}
static int
symbol_type(elf_file_t ef, Elf_Size r_info)
{
const Elf_Sym *ref;
if (ELF_R_SYM(r_info)) {
ref = ef->symtab + ELF_R_SYM(r_info);
return (ELF_ST_TYPE(ref->st_info));
}
return (STT_NOTYPE);
}
static int
relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc,
bool ifuncs)
{
const Elf_Rel *rel;
const Elf_Rela *rela;
const char *symname;
#define APPLY_RELOCS(iter, tbl, tblsize, type) do { \
for ((iter) = (tbl); (iter) != NULL && \
(iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \
if ((symbol_type(ef, (iter)->r_info) == \
STT_GNU_IFUNC || \
elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \
continue; \
if (reloc(&ef->lf, (Elf_Addr)ef->address, \
(iter), (type), lookup)) { \
symname = symbol_name(ef, (iter)->r_info); \
printf("link_elf: symbol %s undefined\n", \
symname); \
return (ENOENT); \
} \
} \
} while (0)
APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL);
APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA);
APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL);
APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA);
#undef APPLY_RELOCS
return (0);
}
static int
relocate_file(elf_file_t ef)
{
int error;
error = relocate_file1(ef, elf_lookup, elf_reloc, false);
if (error == 0)
error = relocate_file1(ef, elf_lookup, elf_reloc, true);
return (error);
}
/*
* Hash function for symbol table lookup. Don't even think about changing
* this. It is specified by the System V ABI.
*/
static unsigned long
elf_hash(const char *name)
{
const unsigned char *p = (const unsigned char *) name;
unsigned long h = 0;
unsigned long g;
while (*p != '\0') {
h = (h << 4) + *p++;
if ((g = h & 0xf0000000) != 0)
h ^= g >> 24;
h &= ~g;
}
return (h);
}
static int
link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
{
elf_file_t ef = (elf_file_t) lf;
unsigned long symnum;
const Elf_Sym* symp;
const char *strp;
unsigned long hash;
int i;
/* If we don't have a hash, bail. */
if (ef->buckets == NULL || ef->nbuckets == 0) {
printf("link_elf_lookup_symbol: missing symbol hash table\n");
return (ENOENT);
}
/* First, search hashed global symbols */
hash = elf_hash(name);
symnum = ef->buckets[hash % ef->nbuckets];
while (symnum != STN_UNDEF) {
if (symnum >= ef->nchains) {
printf("%s: corrupt symbol table\n", __func__);
return (ENOENT);
}
symp = ef->symtab + symnum;
if (symp->st_name == 0) {
printf("%s: corrupt symbol table\n", __func__);
return (ENOENT);
}
strp = ef->strtab + symp->st_name;
if (strcmp(name, strp) == 0) {
if (symp->st_shndx != SHN_UNDEF ||
(symp->st_value != 0 &&
(ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
*sym = (c_linker_sym_t) symp;
return (0);
}
return (ENOENT);
}
symnum = ef->chains[symnum];
}
/* If we have not found it, look at the full table (if loaded) */
if (ef->symtab == ef->ddbsymtab)
return (ENOENT);
/* Exhaustive search */
for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
strp = ef->ddbstrtab + symp->st_name;
if (strcmp(name, strp) == 0) {
if (symp->st_shndx != SHN_UNDEF ||
(symp->st_value != 0 &&
(ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
*sym = (c_linker_sym_t) symp;
return (0);
}
return (ENOENT);
}
}
return (ENOENT);
}
static int
link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
linker_symval_t *symval)
{
elf_file_t ef;
const Elf_Sym *es;
caddr_t val;
ef = (elf_file_t)lf;
es = (const Elf_Sym *)sym;
if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
symval->name = ef->strtab + es->st_name;
val = (caddr_t)ef->address + es->st_value;
if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
val = ((caddr_t (*)(void))val)();
symval->value = val;
symval->size = es->st_size;
return (0);
}
if (ef->symtab == ef->ddbsymtab)
return (ENOENT);
if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
symval->name = ef->ddbstrtab + es->st_name;
val = (caddr_t)ef->address + es->st_value;
if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
val = ((caddr_t (*)(void))val)();
symval->value = val;
symval->size = es->st_size;
return (0);
}
return (ENOENT);
}
static int
link_elf_search_symbol(linker_file_t lf, caddr_t value,
c_linker_sym_t *sym, long *diffp)
{
elf_file_t ef = (elf_file_t) lf;
u_long off = (uintptr_t) (void *) value;
u_long diff = off;
u_long st_value;
const Elf_Sym* es;
const Elf_Sym* best = NULL;
int i;
for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
if (es->st_name == 0)
continue;
st_value = es->st_value + (uintptr_t) (void *) ef->address;
if (off >= st_value) {
if (off - st_value < diff) {
diff = off - st_value;
best = es;
if (diff == 0)
break;
} else if (off - st_value == diff) {
best = es;
}
}
}
if (best == NULL)
*diffp = off;
else
*diffp = diff;
*sym = (c_linker_sym_t) best;
return (0);
}
/*
* Look up a linker set on an ELF system.
*/
static int
link_elf_lookup_set(linker_file_t lf, const char *name,
void ***startp, void ***stopp, int *countp)
{
c_linker_sym_t sym;
linker_symval_t symval;
char *setsym;
void **start, **stop;
int len, error = 0, count;
len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
setsym = malloc(len, M_LINKER, M_WAITOK);
/* get address of first entry */
snprintf(setsym, len, "%s%s", "__start_set_", name);
error = link_elf_lookup_symbol(lf, setsym, &sym);
if (error != 0)
goto out;
link_elf_symbol_values(lf, sym, &symval);
if (symval.value == 0) {
error = ESRCH;
goto out;
}
start = (void **)symval.value;
/* get address of last entry */
snprintf(setsym, len, "%s%s", "__stop_set_", name);
error = link_elf_lookup_symbol(lf, setsym, &sym);
if (error != 0)
goto out;
link_elf_symbol_values(lf, sym, &symval);
if (symval.value == 0) {
error = ESRCH;
goto out;
}
stop = (void **)symval.value;
/* and the number of entries */
count = stop - start;
/* and copy out */
if (startp != NULL)
*startp = start;
if (stopp != NULL)
*stopp = stop;
if (countp != NULL)
*countp = count;
out:
free(setsym, M_LINKER);
return (error);
}
static int
link_elf_each_function_name(linker_file_t file,
int (*callback)(const char *, void *), void *opaque)
{
elf_file_t ef = (elf_file_t)file;
const Elf_Sym *symp;
int i, error;
/* Exhaustive search */
for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
if (symp->st_value != 0 &&
(ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
error = callback(ef->ddbstrtab + symp->st_name, opaque);
if (error != 0)
return (error);
}
}
return (0);
}
static int
link_elf_each_function_nameval(linker_file_t file,
linker_function_nameval_callback_t callback, void *opaque)
{
linker_symval_t symval;
elf_file_t ef = (elf_file_t)file;
const Elf_Sym* symp;
int i, error;
/* Exhaustive search */
for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
if (symp->st_value != 0 &&
(ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
error = link_elf_symbol_values(file,
(c_linker_sym_t) symp, &symval);
if (error != 0)
return (error);
error = callback(file, i, &symval, opaque);
if (error != 0)
return (error);
}
}
return (0);
}
const Elf_Sym *
elf_get_sym(linker_file_t lf, Elf_Size symidx)
{
elf_file_t ef = (elf_file_t)lf;
if (symidx >= ef->nchains)
return (NULL);
return (ef->symtab + symidx);
}
const char *
elf_get_symname(linker_file_t lf, Elf_Size symidx)
{
elf_file_t ef = (elf_file_t)lf;
const Elf_Sym *sym;
if (symidx >= ef->nchains)
return (NULL);
sym = ef->symtab + symidx;
return (ef->strtab + sym->st_name);
}
/*
* Symbol lookup function that can be used when the symbol index is known (ie
* in relocations). It uses the symbol index instead of doing a fully fledged
* hash table based lookup when such is valid. For example for local symbols.
* This is not only more efficient, it's also more correct. It's not always
* the case that the symbol can be found through the hash table.
*/
static int
elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
{
elf_file_t ef = (elf_file_t)lf;
const Elf_Sym *sym;
const char *symbol;
Elf_Addr addr, start, base;
/* Don't even try to lookup the symbol if the index is bogus. */
if (symidx >= ef->nchains) {
*res = 0;
return (EINVAL);
}
sym = ef->symtab + symidx;
/*
* Don't do a full lookup when the symbol is local. It may even
* fail because it may not be found through the hash table.
*/
if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
/* Force lookup failure when we have an insanity. */
if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
*res = 0;
return (EINVAL);
}
*res = ((Elf_Addr)ef->address + sym->st_value);
return (0);
}
/*
* XXX we can avoid doing a hash table based lookup for global
* symbols as well. This however is not always valid, so we'll
* just do it the hard way for now. Performance tweaks can
* always be added.
*/
symbol = ef->strtab + sym->st_name;
/* Force a lookup failure if the symbol name is bogus. */
if (*symbol == 0) {
*res = 0;
return (EINVAL);
}
addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
*res = 0;
return (EINVAL);
}
if (elf_set_find(&set_pcpu_list, addr, &start, &base))
addr = addr - start + base;
#ifdef VIMAGE
else if (elf_set_find(&set_vnet_list, addr, &start, &base))
addr = addr - start + base;
#endif
*res = addr;
return (0);
}
static void
link_elf_reloc_local(linker_file_t lf)
{
const Elf_Rel *rellim;
const Elf_Rel *rel;
const Elf_Rela *relalim;
const Elf_Rela *rela;
elf_file_t ef = (elf_file_t)lf;
/* Perform relocations without addend if there are any: */
if ((rel = ef->rel) != NULL) {
rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
while (rel < rellim) {
elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
ELF_RELOC_REL, elf_lookup);
rel++;
}
}
/* Perform relocations with addend if there are any: */
if ((rela = ef->rela) != NULL) {
relalim = (const Elf_Rela *)
((const char *)ef->rela + ef->relasize);
while (rela < relalim) {
elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
ELF_RELOC_RELA, elf_lookup);
rela++;
}
}
}
static long
link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
{
elf_file_t ef = (elf_file_t)lf;
*symtab = ef->ddbsymtab;
if (*symtab == NULL)
return (0);
return (ef->ddbsymcnt);
}
static long
link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
{
elf_file_t ef = (elf_file_t)lf;
*strtab = ef->ddbstrtab;
if (*strtab == NULL)
return (0);
return (ef->ddbstrcnt);
}
#if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) || defined(__powerpc__)
/*
* Use this lookup routine when performing relocations early during boot.
* The generic lookup routine depends on kobj, which is not initialized
* at that point.
*/
static int
elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused,
Elf_Addr *res)
{
elf_file_t ef;
const Elf_Sym *symp;
caddr_t val;
ef = (elf_file_t)lf;
symp = ef->symtab + symidx;
if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) {
val = (caddr_t)ef->address + symp->st_value;
*res = ((Elf_Addr (*)(void))val)();
return (0);
}
return (ENOENT);
}
void
link_elf_ireloc(caddr_t kmdp)
{
struct elf_file eff;
elf_file_t ef;
ef = &eff;
bzero_early(ef, sizeof(*ef));
ef->modptr = kmdp;
ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
#ifdef RELOCATABLE_KERNEL
ef->address = (caddr_t) (__startkernel - KERNBASE);
#else
ef->address = 0;
#endif
parse_dynamic(ef);
link_elf_preload_parse_symbols(ef);
relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true);
}
#if defined(__aarch64__) || defined(__amd64__)
void
link_elf_late_ireloc(void)
{
elf_file_t ef;
KASSERT(linker_kernel_file != NULL,
("link_elf_late_ireloc: No kernel linker file found"));
ef = (elf_file_t)linker_kernel_file;
relocate_file1(ef, elf_lookup_ifunc, elf_reloc_late, true);
}
#endif
#endif
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