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gems-kernel/source/THIRDPARTY/xnu/libkern/kxld/kxld_reloc.c

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add darwin/xnu functionality
2024-06-03 16:29:39 +00:00
/*
* Copyright (c) 2007-2020 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#include <string.h>
#include <mach/boolean.h>
#include <sys/types.h>
#include <os/base.h>
#if KERNEL
#include <libkern/libkern.h>
#include <mach/machine.h>
#else
#define __SPI_AVAILABLE(...)
#include <stdlib.h>
#include <libkern/OSByteOrder.h>
/* Get machine.h from the kernel source so we can support all platforms
* that the kernel supports. Otherwise we're at the mercy of the host.
*/
#include "../../osfmk/mach/machine.h"
#endif
#define DEBUG_ASSERT_COMPONENT_NAME_STRING "kxld"
#include <AssertMacros.h>
#include "kxld_array.h"
#include "kxld_demangle.h"
#include "kxld_dict.h"
#include "kxld_reloc.h"
#include "kxld_sect.h"
#include "kxld_seg.h"
#include "kxld_sym.h"
#include "kxld_symtab.h"
#include "kxld_util.h"
#include "kxld_vtable.h"
#if KXLD_PIC_KEXTS
/* This will try to pull in mach/machine.h, so it has to come after the
* explicit include above.
*/
#include <mach-o/loader.h>
#endif
/* include target-specific relocation prototypes */
#include <mach-o/reloc.h>
#if KXLD_USER_OR_X86_64
#include <mach-o/x86_64/reloc.h>
#endif
#if KXLD_USER_OR_ARM
#include <mach-o/arm/reloc.h>
#endif
#if KXLD_USER_OR_ARM64
#include <mach-o/arm64/reloc.h>
#endif
extern uint32_t kaslr_offsets_index;
extern uint32_t kaslr_offsets_count;
extern uint32_t *kaslr_offsets;
#define KXLD_TARGET_NONE (u_int) 0x0
#define KXLD_TARGET_VALUE (u_int) 0x1
#define KXLD_TARGET_SECTNUM (u_int) 0x2
#define KXLD_TARGET_SYMBOLNUM (u_int) 0x3
#define KXLD_TARGET_LOOKUP (u_int) 0x4
#define KXLD_TARGET_GOT (u_int) 0x5
#define ABSOLUTE_VALUE(x) (((x) < 0) ? -(x) : (x))
#define LO16(x) (0x0000FFFF & x)
#define LO16S(x) ((0x0000FFFF & x) << 16)
#define HI16(x) (0xFFFF0000 & x)
#define HI16S(x) ((0xFFFF0000 & x) >> 16)
#define BIT15(x) (0x00008000 & x)
#define BR14I(x) (0xFFFF0003 & x)
#define BR14D(x) (0x0000FFFC & x)
#define BR24I(x) (0xFC000003 & x)
#define BR24D(x) (0x03FFFFFC & x)
#define HADISP 0x00010000
#define BR14_LIMIT 0x00008000
#define BR24_LIMIT 0x02000000
#define IS_COND_BR_INSTR(x) ((x & 0xFC000000) == 0x40000000)
#define IS_NOT_ALWAYS_TAKEN(x) ((x & 0x03E00000) != 0x02800000)
#define FLIP_PREDICT_BIT(x) x ^= 0x00200000
#define SIGN_EXTEND_MASK(n) (1 << ((n) - 1))
#define SIGN_EXTEND(x, n) (((x) ^ SIGN_EXTEND_MASK(n)) - SIGN_EXTEND_MASK(n))
#define BR14_NBITS_DISPLACEMENT 16
#define BR24_NBITS_DISPLACEMENT 26
#define X86_64_RIP_RELATIVE_LIMIT 0x80000000UL
/*******************************************************************************
* Prototypes
*******************************************************************************/
#if KXLD_USER_OR_I386
static boolean_t generic_reloc_has_pair(u_int _type)
__attribute__((const));
static u_int generic_reloc_get_pair_type(u_int _prev_type)
__attribute__((const));
static boolean_t generic_reloc_has_got(u_int _type)
__attribute__((const));
static kern_return_t generic_process_reloc(const KXLDRelocator *relocator,
u_char *instruction, u_int length, u_int pcrel, kxld_addr_t base_pc,
kxld_addr_t link_pc, kxld_addr_t link_disp, u_int type, kxld_addr_t target,
kxld_addr_t pair_target, boolean_t swap);
#endif /* KXLD_USER_OR_I386 */
#if KXLD_USER_OR_X86_64
static boolean_t x86_64_reloc_has_pair(u_int _type)
__attribute__((const));
static u_int x86_64_reloc_get_pair_type(u_int _prev_type)
__attribute__((const));
static boolean_t x86_64_reloc_has_got(u_int _type)
__attribute__((const));
static kern_return_t x86_64_process_reloc(const KXLDRelocator *relocator,
u_char *instruction, u_int length, u_int pcrel, kxld_addr_t base_pc,
kxld_addr_t link_pc, kxld_addr_t link_disp, u_int type, kxld_addr_t target,
kxld_addr_t pair_target, boolean_t swap);
static kern_return_t calculate_displacement_x86_64(uint64_t target,
uint64_t adjustment, int32_t *instr32);
#endif /* KXLD_USER_OR_X86_64 */
#if KXLD_USER_OR_ARM
static boolean_t arm_reloc_has_pair(u_int _type)
__attribute__((const));
static u_int arm_reloc_get_pair_type(u_int _prev_type)
__attribute__((const));
static boolean_t arm_reloc_has_got(u_int _type)
__attribute__((const));
static kern_return_t arm_process_reloc(const KXLDRelocator *relocator,
u_char *instruction, u_int length, u_int pcrel, kxld_addr_t base_pc,
kxld_addr_t link_pc, kxld_addr_t link_disp, u_int type, kxld_addr_t target,
kxld_addr_t pair_target, boolean_t swap);
#endif /* KXLD_USER_OR_ARM */
#if KXLD_USER_OR_ARM64
static boolean_t arm64_reloc_has_pair(u_int _type)
__attribute__((const));
static u_int arm64_reloc_get_pair_type(u_int _prev_type)
__attribute__((const));
static boolean_t arm64_reloc_has_got(u_int _type)
__attribute__((const));
static kern_return_t arm64_process_reloc(const KXLDRelocator *relocator,
u_char *instruction, u_int length, u_int pcrel, kxld_addr_t base_pc,
kxld_addr_t link_pc, kxld_addr_t link_disp, u_int type, kxld_addr_t target,
kxld_addr_t pair_target, boolean_t swap);
#endif /* KXLD_USER_OR_ARM64 */
#if KXLD_USER_OR_ILP32
static kxld_addr_t get_pointer_at_addr_32(const KXLDRelocator *relocator,
const u_char *data, u_long offset)
__attribute__((pure, nonnull));
#endif /* KXLD_USER_OR_ILP32 */
#if KXLD_USER_OR_LP64
static kxld_addr_t get_pointer_at_addr_64(const KXLDRelocator *relocator,
const u_char *data, u_long offset)
__attribute__((pure, nonnull));
#endif /* KXLD_USER_OR_LP64 */
static u_int count_relocatable_relocs(const KXLDRelocator *relocator,
const struct relocation_info *relocs, u_int nrelocs)
__attribute__((pure));
static kern_return_t calculate_targets(KXLDRelocator *relocator,
kxld_addr_t *_target, kxld_addr_t *_pair_target, const KXLDReloc *reloc);
static kxld_addr_t align_raw_function_address(const KXLDRelocator *relocator,
kxld_addr_t value);
static kern_return_t get_target_by_address_lookup(kxld_addr_t *target,
kxld_addr_t addr, const KXLDArray *sectarray);
static kern_return_t check_for_direct_pure_virtual_call(
const KXLDRelocator *relocator, u_long offset);
#if KXLD_PIC_KEXTS
static u_long get_macho_data_size_for_array(const KXLDArray *relocs);
static kern_return_t export_macho_for_array(const KXLDRelocator *relocator,
const KXLDArray *relocs, struct relocation_info **dstp);
#endif /* KXLD_PIC_KEXTS */
/*******************************************************************************
*******************************************************************************/
kern_return_t
kxld_relocator_init(KXLDRelocator *relocator, u_char *file,
const KXLDSymtab *symtab, const KXLDArray *sectarray, cpu_type_t cputype,
cpu_subtype_t cpusubtype __unused, boolean_t swap)
{
kern_return_t rval = KERN_FAILURE;
check(relocator);
switch (cputype) {
#if KXLD_USER_OR_I386
case CPU_TYPE_I386:
relocator->reloc_has_pair = generic_reloc_has_pair;
relocator->reloc_get_pair_type = generic_reloc_get_pair_type;
relocator->reloc_has_got = generic_reloc_has_got;
relocator->process_reloc = generic_process_reloc;
relocator->function_align = 0;
relocator->is_32_bit = TRUE;
relocator->may_scatter = TRUE;
break;
#endif /* KXLD_USER_OR_I386 */
#if KXLD_USER_OR_X86_64
case CPU_TYPE_X86_64:
relocator->reloc_has_pair = x86_64_reloc_has_pair;
relocator->reloc_get_pair_type = x86_64_reloc_get_pair_type;
relocator->reloc_has_got = x86_64_reloc_has_got;
relocator->process_reloc = x86_64_process_reloc;
relocator->function_align = 0;
relocator->is_32_bit = FALSE;
relocator->may_scatter = FALSE;
break;
#endif /* KXLD_USER_OR_X86_64 */
#if KXLD_USER_OR_ARM
case CPU_TYPE_ARM:
relocator->reloc_has_pair = arm_reloc_has_pair;
relocator->reloc_get_pair_type = arm_reloc_get_pair_type;
relocator->reloc_has_got = arm_reloc_has_got;
relocator->process_reloc = arm_process_reloc;
relocator->function_align = 1;
relocator->is_32_bit = TRUE;
relocator->may_scatter = FALSE;
break;
#endif /* KXLD_USER_OR_ARM */
#if KXLD_USER_OR_ARM64
case CPU_TYPE_ARM64:
relocator->reloc_has_pair = arm64_reloc_has_pair;
relocator->reloc_get_pair_type = arm64_reloc_get_pair_type;
relocator->reloc_has_got = arm64_reloc_has_got;
relocator->process_reloc = arm64_process_reloc;
relocator->function_align = 0;
relocator->is_32_bit = FALSE;
relocator->may_scatter = FALSE;
break;
#endif /* KXLD_USER_OR_ARM64 */
default:
rval = KERN_FAILURE;
kxld_log(kKxldLogLinking, kKxldLogErr,
kKxldLogArchNotSupported, cputype);
goto finish;
}
relocator->file = file;
relocator->symtab = symtab;
relocator->sectarray = sectarray;
relocator->is_32_bit = kxld_is_32_bit(cputype);
relocator->swap = swap;
rval = KERN_SUCCESS;
finish:
return rval;
}
/*******************************************************************************
*******************************************************************************/
kern_return_t
kxld_reloc_create_macho(KXLDArray *relocarray, const KXLDRelocator *relocator,
const struct relocation_info *srcs, u_int nsrcs)
{
kern_return_t rval = KERN_FAILURE;
KXLDReloc *reloc = NULL;
u_int nrelocs = 0;
const struct relocation_info *src = NULL;
const struct scattered_relocation_info *scatsrc = NULL;
u_int i = 0;
u_int reloc_index = 0;
check(relocarray);
check(srcs);
/* If there are no relocation entries, just return */
if (!nsrcs) {
rval = KERN_SUCCESS;
goto finish;
}
/* Count the number of non-pair relocs */
nrelocs = count_relocatable_relocs(relocator, srcs, nsrcs);
if (nrelocs) {
/* Allocate the array of relocation entries */
rval = kxld_array_init(relocarray, sizeof(KXLDReloc), nrelocs);
require_noerr(rval, finish);
/* Initialize the relocation entries */
for (i = 0; i < nsrcs; ++i) {
src = srcs + i;
scatsrc = (const struct scattered_relocation_info *) src;
/* A section-based relocation entry can be skipped for absolute
* symbols.
*/
if (!(relocator->may_scatter && (src->r_address & R_SCATTERED)) &&
!(src->r_extern) && (R_ABS == src->r_symbolnum)) {
continue;
}
/* Pull out the data from the relocation entries. The target_type
* depends on the r_extern bit:
* Scattered -> Section Lookup by Address
* Local (not extern) -> Section by Index
* Extern -> Symbolnum by Index
*/
reloc = kxld_array_get_item(relocarray, reloc_index++);
if (relocator->may_scatter && (src->r_address & R_SCATTERED)) {
reloc->address = scatsrc->r_address;
reloc->pcrel = scatsrc->r_pcrel;
reloc->length = scatsrc->r_length;
reloc->reloc_type = scatsrc->r_type;
reloc->target = scatsrc->r_value;
reloc->target_type = KXLD_TARGET_LOOKUP;
} else {
reloc->address = src->r_address;
reloc->pcrel = src->r_pcrel;
reloc->length = src->r_length;
reloc->reloc_type = src->r_type;
reloc->target = src->r_symbolnum;
if (0 == src->r_extern) {
reloc->target_type = KXLD_TARGET_SECTNUM;
reloc->target -= 1;
} else {
reloc->target_type = KXLD_TARGET_SYMBOLNUM;
}
}
/* Find the pair entry if it exists */
if (relocator->reloc_has_pair(reloc->reloc_type)) {
++i;
require_action(i < nsrcs, finish, rval = KERN_FAILURE);
src = srcs + i;
scatsrc = (const struct scattered_relocation_info *) src;
if (relocator->may_scatter && (src->r_address & R_SCATTERED)) {
require_action(relocator->reloc_get_pair_type(
reloc->reloc_type) == scatsrc->r_type,
finish, rval = KERN_FAILURE);
reloc->pair_address = scatsrc->r_address;
reloc->pair_target = scatsrc->r_value;
reloc->pair_target_type = KXLD_TARGET_LOOKUP;
} else {
require_action(relocator->reloc_get_pair_type(
reloc->reloc_type) == scatsrc->r_type,
finish, rval = KERN_FAILURE);
reloc->pair_address = scatsrc->r_address;
if (src->r_extern) {
reloc->pair_target = src->r_symbolnum;
reloc->pair_target_type = KXLD_TARGET_SYMBOLNUM;
} else {
reloc->pair_target = src->r_address;
reloc->pair_target_type = KXLD_TARGET_VALUE;
}
}
} else {
reloc->pair_target = 0;
if (relocator->reloc_has_got(reloc->reloc_type)) {
reloc->pair_target_type = KXLD_TARGET_GOT;
} else {
reloc->pair_target_type = KXLD_TARGET_NONE;
}
}
} // for...
}
rval = KERN_SUCCESS;
finish:
return rval;
}
/*******************************************************************************
* Relocatable relocs :
* 1) Are not _PAIR_ relocs
* 2) Don't reference N_ABS symbols
*******************************************************************************/
static u_int
count_relocatable_relocs(const KXLDRelocator *relocator,
const struct relocation_info *relocs, u_int nrelocs)
{
u_int num_nonpair_relocs = 0;
u_int i = 0;
const struct relocation_info *reloc = NULL;
const struct scattered_relocation_info *sreloc = NULL;
check(relocator);
check(relocs);
/* Loop over all of the relocation entries */
num_nonpair_relocs = 1;
for (i = 1; i < nrelocs; ++i) {
reloc = relocs + i;
if (reloc->r_address & R_SCATTERED) {
/* A scattered relocation entry is relocatable as long as it's not a
* pair.
*/
sreloc = (const struct scattered_relocation_info *) reloc;
num_nonpair_relocs +=
!relocator->reloc_has_pair(sreloc->r_type);
} else {
/* A normal relocation entry is relocatable if it is not a pair and
* if it is not a section-based relocation for an absolute symbol.
*/
num_nonpair_relocs +=
!(relocator->reloc_has_pair(reloc->r_type)
|| (0 == reloc->r_extern && R_ABS == reloc->r_symbolnum));
}
}
return num_nonpair_relocs;
}
/*******************************************************************************
*******************************************************************************/
void
kxld_relocator_clear(KXLDRelocator *relocator)
{
bzero(relocator, sizeof(*relocator));
}
/*******************************************************************************
*******************************************************************************/
boolean_t
kxld_relocator_has_pair(const KXLDRelocator *relocator, u_int r_type)
{
check(relocator);
return relocator->reloc_has_pair(r_type);
}
/*******************************************************************************
*******************************************************************************/
u_int
kxld_relocator_get_pair_type(const KXLDRelocator *relocator,
u_int prev_r_type)
{
check(relocator);
return relocator->reloc_get_pair_type(prev_r_type);
}
/*******************************************************************************
*******************************************************************************/
boolean_t
kxld_relocator_has_got(const KXLDRelocator *relocator, u_int r_type)
{
check(relocator);
return relocator->reloc_has_got(r_type);
}
/*******************************************************************************
*******************************************************************************/
KXLDSym *
kxld_reloc_get_symbol(const KXLDRelocator *relocator, const KXLDReloc *reloc,
const u_char *data)
{
KXLDSym *sym = NULL;
kxld_addr_t value = 0;
check(reloc);
switch (reloc->target_type) {
case KXLD_TARGET_SYMBOLNUM:
sym = kxld_symtab_get_symbol_by_index(relocator->symtab, reloc->target);
break;
case KXLD_TARGET_SECTNUM:
if (data) {
value = kxld_relocator_get_pointer_at_addr(relocator, data,
reloc->address);
sym = kxld_symtab_get_cxx_symbol_by_value(relocator->symtab, value);
}
break;
default:
sym = NULL;
break;
}
return sym;
}
/*******************************************************************************
*******************************************************************************/
kern_return_t
kxld_reloc_get_reloc_index_by_offset(const KXLDArray *relocs,
kxld_size_t offset, u_int *idx)
{
kern_return_t rval = KERN_FAILURE;
KXLDReloc *reloc = NULL;
u_int i = 0;
for (i = 0; i < relocs->nitems; ++i) {
reloc = kxld_array_get_item(relocs, i);
if (reloc->address == offset) {
break;
}
}
if (i >= relocs->nitems) {
rval = KERN_FAILURE;
goto finish;
}
*idx = i;
rval = KERN_SUCCESS;
finish:
return rval;
}
/*******************************************************************************
*******************************************************************************/
KXLDReloc *
kxld_reloc_get_reloc_by_offset(const KXLDArray *relocs, kxld_addr_t offset)
{
kern_return_t rval = KERN_FAILURE;
KXLDReloc *reloc = NULL;
u_int i = 0;
rval = kxld_reloc_get_reloc_index_by_offset(relocs, offset, &i);
if (rval) {
goto finish;
}
reloc = kxld_array_get_item(relocs, i);
finish:
return reloc;
}
#if KXLD_PIC_KEXTS
/*******************************************************************************
*******************************************************************************/
u_long
kxld_reloc_get_macho_header_size(void)
{
return sizeof(struct dysymtab_command);
}
/*******************************************************************************
*******************************************************************************/
u_long
kxld_reloc_get_macho_data_size(
const KXLDArray *locrelocs,
const KXLDArray *extrelocs)
{
u_long rval = 0;
rval += get_macho_data_size_for_array(locrelocs);
rval += get_macho_data_size_for_array(extrelocs);
return rval;
}
/*******************************************************************************
*******************************************************************************/
kern_return_t
kxld_reloc_export_macho(const KXLDRelocator *relocator,
const KXLDArray *locrelocs, const KXLDArray *extrelocs,
u_char *buf, u_long *header_offset, u_long header_size,
u_long *data_offset, u_long size)
{
kern_return_t rval = KERN_FAILURE;
struct dysymtab_command *dysymtabhdr = NULL;
struct relocation_info *start = NULL;
struct relocation_info *dst = NULL;
u_long count = 0;
u_long data_size = 0;
check(locrelocs);
check(extrelocs);
check(buf);
check(header_offset);
check(data_offset);
require_action(sizeof(*dysymtabhdr) <= header_size - *header_offset, finish, rval = KERN_FAILURE);
dysymtabhdr = (struct dysymtab_command *) ((void *) (buf + *header_offset));
*header_offset += sizeof(*dysymtabhdr);
data_size = kxld_reloc_get_macho_data_size(locrelocs, extrelocs);
require_action((*data_offset + data_size) <= size, finish, rval = KERN_FAILURE);
start = dst = (struct relocation_info *) ((void *) (buf + *data_offset));
if (kaslr_offsets == NULL) {
kaslr_offsets_index = 0;
kaslr_offsets_count = locrelocs->nitems + extrelocs->nitems;
kaslr_offsets = (uint32_t *)calloc(kaslr_offsets_count, sizeof(*kaslr_offsets));
}
// copies the reloc data into the __LINKEDIT segment
// data_offset is the new value for locreloff
rval = export_macho_for_array(relocator, locrelocs, &dst);
require_noerr(rval, finish);
rval = export_macho_for_array(relocator, extrelocs, &dst);
require_noerr(rval, finish);
count = dst - start;
memset(dysymtabhdr, 0, sizeof(*dysymtabhdr));
dysymtabhdr->cmd = LC_DYSYMTAB;
dysymtabhdr->cmdsize = (uint32_t) sizeof(*dysymtabhdr);
dysymtabhdr->locreloff = (uint32_t) *data_offset;
dysymtabhdr->nlocrel = (uint32_t) count;
*data_offset += count * sizeof(struct relocation_info);
#if SPLIT_KEXTS_DEBUG
kxld_log(kKxldLogLinking, kKxldLogErr,
"%p >>> Start of dysymtabhdr (size %lu) <%s> ",
(void *) dysymtabhdr,
sizeof(*dysymtabhdr),
__func__);
kxld_log(kKxldLogLinking, kKxldLogErr,
"%p <<< End of dysymtabhdr <%s> ",
(void *) ((u_char *)dysymtabhdr + sizeof(*dysymtabhdr)),
__func__);
kxld_log(kKxldLogLinking, kKxldLogErr,
"dysymtabhdr at %p: cmdsize %u indirectsymoff %u nindirectsyms %u extreloff %u nextrel %u locreloff %u nlocrel %u <%s>",
(void *) dysymtabhdr,
dysymtabhdr->cmdsize,
dysymtabhdr->indirectsymoff,
dysymtabhdr->nindirectsyms,
dysymtabhdr->extreloff,
dysymtabhdr->nextrel,
dysymtabhdr->locreloff,
dysymtabhdr->nlocrel,
__func__);
#endif
rval = KERN_SUCCESS;
finish:
return rval;
}
#endif /* KXLD_PIC_KEXTS */
/*******************************************************************************
*******************************************************************************/
kxld_addr_t
kxld_relocator_get_pointer_at_addr(const KXLDRelocator *relocator,
const u_char *data, u_long offset)
{
kxld_addr_t value;
KXLD_3264_FUNC(relocator->is_32_bit, value,
get_pointer_at_addr_32, get_pointer_at_addr_64,
relocator, data, offset);
return value;
}
#if KXLD_USER_OR_ILP32
/*******************************************************************************
*******************************************************************************/
static kxld_addr_t
get_pointer_at_addr_32(const KXLDRelocator *relocator,
const u_char *data, u_long offset)
{
uint32_t addr = 0;
check(relocator);
addr = *(const uint32_t *) ((const void *) (data + offset));
#if !KERNEL
if (relocator->swap) {
addr = OSSwapInt32(addr);
}
#endif
return align_raw_function_address(relocator, addr);
}
#endif /* KXLD_USER_OR_ILP32 */
#if KXLD_USER_OR_LP64
/*******************************************************************************
*******************************************************************************/
static kxld_addr_t
get_pointer_at_addr_64(const KXLDRelocator *relocator,
const u_char *data, u_long offset)
{
uint64_t addr = 0;
check(relocator);
addr = *(const uint64_t *) ((const void *) (data + offset));
#if !KERNEL
if (relocator->swap) {
addr = OSSwapInt64(addr);
}
#endif
return align_raw_function_address(relocator, addr);
}
#endif /* KXLD_USER_OR_LP64 */
/*******************************************************************************
*******************************************************************************/
void
kxld_relocator_set_vtables(KXLDRelocator *relocator, const KXLDDict *vtables)
{
relocator->vtables = vtables;
}
/*******************************************************************************
* When we're inspecting the raw binary and not the symbol table, value may
* hold a THUMB address (with bit 0 set to 1) but the index will have the real
* address (bit 0 set to 0). So if bit 0 is set here, we clear it. This only
* impacts ARM for now, but it's implemented as a generic function alignment
* mask.
*******************************************************************************/
static kxld_addr_t
align_raw_function_address(const KXLDRelocator *relocator, kxld_addr_t value)
{
if (relocator->function_align) {
value &= ~((1ULL << relocator->function_align) - 1);
}
return value;
}
/*******************************************************************************
*******************************************************************************/
kern_return_t
kxld_relocator_process_sect_reloc(KXLDRelocator *relocator,
const KXLDReloc *reloc, const KXLDSect *sect)
{
kern_return_t rval = KERN_FAILURE;
u_char *instruction = NULL;
kxld_addr_t target = 0;
kxld_addr_t pair_target = 0;
kxld_addr_t base_pc = 0;
kxld_addr_t link_pc = 0;
kxld_addr_t link_disp = 0;
check(relocator);
check(reloc);
check(sect);
/* Find the instruction */
instruction = sect->data + reloc->address;
/* Calculate the target */
rval = calculate_targets(relocator, &target, &pair_target, reloc);
require_noerr(rval, finish);
base_pc = reloc->address;
link_pc = base_pc + sect->link_addr;
link_disp = sect->link_addr - sect->base_addr;
/* Relocate */
rval = relocator->process_reloc(relocator, instruction, reloc->length,
reloc->pcrel, base_pc, link_pc, link_disp, reloc->reloc_type, target,
pair_target, relocator->swap);
require_noerr(rval, finish);
/* Return */
relocator->current_vtable = NULL;
rval = KERN_SUCCESS;
finish:
return rval;
}
/*******************************************************************************
*******************************************************************************/
kern_return_t
kxld_reloc_update_symindex(KXLDReloc *reloc, u_int symindex)
{
kern_return_t rval = KERN_FAILURE;
require_action(reloc->target_type == KXLD_TARGET_SYMBOLNUM,
finish, rval = KERN_FAILURE);
reloc->target = symindex;
rval = KERN_SUCCESS;
finish:
return rval;
}
/*******************************************************************************
*******************************************************************************/
kern_return_t
kxld_relocator_process_table_reloc(KXLDRelocator *relocator,
const KXLDReloc *reloc,
const KXLDSeg *seg,
kxld_addr_t link_addr)
{
kern_return_t rval = KERN_FAILURE;
u_char *instruction = NULL;
kxld_addr_t target = 0;
kxld_addr_t pair_target = 0;
kxld_addr_t base_pc = 0;
kxld_addr_t link_pc = 0;
u_long offset = 0;
check(relocator);
check(reloc);
/* Find the instruction in original kext file we are trying to link */
offset = (u_long)(seg->fileoff + (reloc->address - seg->base_addr));
instruction = relocator->file + offset;
/* Calculate the target */
rval = calculate_targets(relocator, &target, &pair_target, reloc);
require_noerr(rval, finish);
base_pc = reloc->address;
link_pc = base_pc + link_addr;
if (kxld_seg_is_split_seg(seg)) {
// link_pc for split segment special case, do not add in the base_pc
link_pc = link_addr;
}
/* Relocate */
rval = relocator->process_reloc(relocator, instruction, reloc->length,
reloc->pcrel, base_pc, link_pc, link_addr, reloc->reloc_type, target,
pair_target, relocator->swap);
require_noerr(rval, finish);
/* Return */
relocator->current_vtable = NULL;
rval = KERN_SUCCESS;
finish:
return rval;
}
/*******************************************************************************
*******************************************************************************/
static kern_return_t
calculate_targets(KXLDRelocator *relocator, kxld_addr_t *_target,
kxld_addr_t *_pair_target, const KXLDReloc *reloc)
{
kern_return_t rval = KERN_FAILURE;
const KXLDSect *sect = NULL;
const KXLDSym *sym = NULL;
kxld_addr_t target = 0;
kxld_addr_t pair_target = 0;
char *demangled_name = NULL;
size_t demangled_length = 0;
check(_target);
check(_pair_target);
*_target = 0;
*_pair_target = 0;
/* Find the target based on the lookup type */
switch (reloc->target_type) {
case KXLD_TARGET_LOOKUP:
require_action(reloc->pair_target_type == KXLD_TARGET_NONE ||
reloc->pair_target_type == KXLD_TARGET_LOOKUP ||
reloc->pair_target_type == KXLD_TARGET_VALUE,
finish, rval = KERN_FAILURE);
rval = get_target_by_address_lookup(&target, reloc->target,
relocator->sectarray);
require_noerr(rval, finish);
if (reloc->pair_target_type == KXLD_TARGET_LOOKUP) {
rval = get_target_by_address_lookup(&pair_target,
reloc->pair_target, relocator->sectarray);
require_noerr(rval, finish);
} else if (reloc->pair_target_type == KXLD_TARGET_VALUE) {
pair_target = reloc->pair_target;
}
break;
case KXLD_TARGET_SECTNUM:
require_action(reloc->pair_target_type == KXLD_TARGET_NONE ||
reloc->pair_target_type == KXLD_TARGET_VALUE,
finish, rval = KERN_FAILURE);
/* Get the target's section by section number */
sect = kxld_array_get_item(relocator->sectarray, reloc->target);
require_action(sect, finish, rval = KERN_FAILURE);
/* target is the change in the section's address */
target = sect->link_addr - sect->base_addr;
if (reloc->pair_target_type) {
pair_target = reloc->pair_target;
} else {
/* x86_64 needs to know when we have a non-external relocation,
* so we hack that information in here.
*/
pair_target = TRUE;
}
break;
case KXLD_TARGET_SYMBOLNUM:
require_action(reloc->pair_target_type == KXLD_TARGET_NONE ||
reloc->pair_target_type == KXLD_TARGET_GOT ||
reloc->pair_target_type == KXLD_TARGET_SYMBOLNUM ||
reloc->pair_target_type == KXLD_TARGET_VALUE, finish,
rval = KERN_FAILURE);
/* Get the target's symbol by symbol number */
sym = kxld_symtab_get_symbol_by_index(relocator->symtab, reloc->target);
require_action(sym, finish, rval = KERN_FAILURE);
/* If this symbol is a padslot that has already been replaced, then the
* only way a relocation entry can still reference it is if there is a
* vtable that has not been patched. The vtable patcher uses the
* MetaClass structure to find classes for patching, so an unpatched
* vtable means that there is an OSObject-dervied class that is missing
* its OSDeclare/OSDefine macros.
*/
if (kxld_sym_is_padslot(sym) && kxld_sym_is_replaced(sym)) {
kxld_log(kKxldLogLinking, kKxldLogErr, kKxldLogRelocatingPatchedSym,
kxld_demangle(sym->name, &demangled_name, &demangled_length));
}
target = sym->link_addr;
if (kxld_sym_is_vtable(sym)) {
relocator->current_vtable = kxld_dict_find(relocator->vtables, sym->name);
}
/* Some relocation types need the GOT entry address instead of the
* symbol's actual address. These types don't have pair relocation
* entries, so we store the GOT entry address as the pair target.
*/
if (reloc->pair_target_type == KXLD_TARGET_VALUE) {
pair_target = reloc->pair_target;
} else if (reloc->pair_target_type == KXLD_TARGET_SYMBOLNUM) {
sym = kxld_symtab_get_symbol_by_index(relocator->symtab,
reloc->pair_target);
require_action(sym, finish, rval = KERN_FAILURE);
pair_target = sym->link_addr;
} else if (reloc->pair_target_type == KXLD_TARGET_GOT) {
pair_target = sym->got_addr;
}
break;
default:
rval = KERN_FAILURE;
goto finish;
}
*_target = target;
*_pair_target = pair_target;
rval = KERN_SUCCESS;
finish:
if (demangled_name) {
kxld_free(demangled_name, demangled_length);
}
return rval;
}
/*******************************************************************************
*******************************************************************************/
static kern_return_t
get_target_by_address_lookup(kxld_addr_t *target, kxld_addr_t addr,
const KXLDArray *sectarray)
{
kern_return_t rval = KERN_FAILURE;
const KXLDSect *sect = NULL;
kxld_addr_t start = 0;
kxld_addr_t end = 0;
u_int i = 0;
check(target);
check(sectarray);
*target = 0;
for (i = 0; i < sectarray->nitems; ++i) {
sect = kxld_array_get_item(sectarray, i);
start = sect->base_addr;
end = start + sect->size;
if (start <= addr && addr < end) {
break;
}
sect = NULL;
}
require_action(sect, finish, rval = KERN_FAILURE);
*target = sect->link_addr - sect->base_addr;
rval = KERN_SUCCESS;
finish:
return rval;
}
/*******************************************************************************
*******************************************************************************/
static kern_return_t
check_for_direct_pure_virtual_call(const KXLDRelocator *relocator, u_long offset)
{
kern_return_t rval = KERN_FAILURE;
const KXLDVTableEntry *entry = NULL;
if (relocator->current_vtable) {
entry = kxld_vtable_get_entry_for_offset(relocator->current_vtable,
offset, relocator->is_32_bit);
require_action(!entry || !entry->patched.name ||
!kxld_sym_name_is_pure_virtual(entry->patched.name),
finish, rval = KERN_FAILURE;
kxld_log(kKxldLogLinking, kKxldLogErr,
kKxldLogDirectPureVirtualCall));
}
rval = KERN_SUCCESS;
finish:
return rval;
}
#if KXLD_PIC_KEXTS
/*******************************************************************************
*******************************************************************************/
static u_long
get_macho_data_size_for_array(const KXLDArray *relocs)
{
const KXLDReloc *reloc = NULL;
u_int i = 0;
u_long size = 0;
check(relocs);
for (i = 0; i < relocs->nitems; ++i) {
reloc = kxld_array_get_item(relocs, i);
if (!reloc->pcrel) {
size += sizeof(struct relocation_info);
if (reloc->pair_target_type != KXLD_TARGET_NONE) {
size += sizeof(struct relocation_info);
}
}
}
return size;
}
/*******************************************************************************
*******************************************************************************/
static kern_return_t
export_macho_for_array(const KXLDRelocator *relocator,
const KXLDArray *relocs, struct relocation_info **dstp)
{
kern_return_t rval = KERN_FAILURE;
const KXLDReloc *reloc = NULL;
struct relocation_info *dst = NULL;
struct scattered_relocation_info *scatdst = NULL;
u_int i = 0;
dst = *dstp;
for (i = 0; i < relocs->nitems; ++i) {
reloc = kxld_array_get_item(relocs, i);
scatdst = (struct scattered_relocation_info *) dst;
if (reloc->pcrel) {
continue;
}
switch (reloc->target_type) {
case KXLD_TARGET_LOOKUP:
if (kaslr_offsets) {
if (kaslr_offsets_index >= kaslr_offsets_count) {
kxld_log(kKxldLogLinking, kKxldLogErr,
"kaslr_offsets overflow %d > %d <%s> ",
kaslr_offsets_index, kaslr_offsets_count,
__func__);
abort();
}
// reloc->address is really an offset from the start of the kext
*(kaslr_offsets + kaslr_offsets_index++) = reloc->address;
}
scatdst->r_address = reloc->address;
scatdst->r_pcrel = reloc->pcrel;
scatdst->r_length = reloc->length;
scatdst->r_type = reloc->reloc_type;
scatdst->r_value = reloc->target;
scatdst->r_scattered = 1;
break;
case KXLD_TARGET_SECTNUM:
if (kaslr_offsets) {
if (kaslr_offsets_index >= kaslr_offsets_count) {
kxld_log(kKxldLogLinking, kKxldLogErr,
"kaslr_offsets overflow <%s> ", __func__);
abort();
}
// reloc->address is really an offset from the start of the kext
*(kaslr_offsets + kaslr_offsets_index++) = reloc->address;
}
dst->r_address = reloc->address;
dst->r_pcrel = reloc->pcrel;
dst->r_length = reloc->length;
dst->r_type = reloc->reloc_type;
dst->r_symbolnum = reloc->target + 1;
dst->r_extern = 0;
break;
case KXLD_TARGET_SYMBOLNUM:
/* Assume that everything will be slid together; otherwise,
* there is no sensible value for the section number.
*/
if (kaslr_offsets) {
if (kaslr_offsets_index >= kaslr_offsets_count) {
kxld_log(kKxldLogLinking, kKxldLogErr,
"kaslr_offsets overflow <%s> ", __func__);
abort();
}
// reloc->address is really an offset from the start of the kext
*(kaslr_offsets + kaslr_offsets_index++) = reloc->address;
}
dst->r_address = reloc->address;
dst->r_pcrel = reloc->pcrel;
dst->r_length = reloc->length;
dst->r_type = reloc->reloc_type;
dst->r_symbolnum = 1;
dst->r_extern = 0;
break;
default:
rval = KERN_FAILURE;
goto finish;
}
++dst;
if (reloc->pair_target_type != KXLD_TARGET_NONE) {
++i;
require_action(i < relocs->nitems, finish, rval = KERN_FAILURE);
scatdst = (struct scattered_relocation_info *) dst;
switch (reloc->pair_target_type) {
case KXLD_TARGET_LOOKUP:
scatdst->r_address = reloc->pair_address;
scatdst->r_pcrel = reloc->pcrel;
scatdst->r_length = reloc->length;
scatdst->r_type = relocator->reloc_get_pair_type(reloc->reloc_type);
scatdst->r_value = reloc->pair_target;
scatdst->r_scattered = 1;
break;
case KXLD_TARGET_SECTNUM:
dst->r_address = reloc->pair_address;
dst->r_pcrel = reloc->pcrel;
dst->r_length = reloc->length;
dst->r_type = relocator->reloc_get_pair_type(reloc->reloc_type);
dst->r_symbolnum = reloc->pair_target + 1;
dst->r_extern = 0;
break;
case KXLD_TARGET_SYMBOLNUM:
dst->r_address = reloc->pair_address;
dst->r_pcrel = reloc->pcrel;
dst->r_length = reloc->length;
dst->r_type = relocator->reloc_get_pair_type(reloc->reloc_type);
dst->r_symbolnum = 1;
dst->r_extern = 0;
break;
default:
rval = KERN_FAILURE;
goto finish;
}
++dst;
}
}
rval = KERN_SUCCESS;
finish:
*dstp = dst;
return rval;
}
#endif /* KXLD_PIC_KEXTS */
#if KXLD_USER_OR_I386
/*******************************************************************************
*******************************************************************************/
static boolean_t
generic_reloc_has_pair(u_int _type)
{
enum reloc_type_generic type = _type;
return type == GENERIC_RELOC_SECTDIFF ||
type == GENERIC_RELOC_LOCAL_SECTDIFF;
}
/*******************************************************************************
*******************************************************************************/
static u_int
generic_reloc_get_pair_type(u_int _prev_type __unused)
{
return GENERIC_RELOC_PAIR;
}
/*******************************************************************************
*******************************************************************************/
static boolean_t
generic_reloc_has_got(u_int _type __unused)
{
return FALSE;
}
/*******************************************************************************
*******************************************************************************/
static kern_return_t
generic_process_reloc(const KXLDRelocator *relocator, u_char *instruction,
u_int length, u_int pcrel, kxld_addr_t _base_pc, kxld_addr_t _link_pc,
kxld_addr_t _link_disp __unused, u_int _type, kxld_addr_t _target,
kxld_addr_t _pair_target, boolean_t swap __unused)
{
kern_return_t rval = KERN_FAILURE;
uint32_t base_pc = (uint32_t) _base_pc;
uint32_t link_pc = (uint32_t) _link_pc;
uint32_t *instr_addr = NULL;
uint32_t instr_data = 0;
uint32_t target = (uint32_t) _target;
uint32_t pair_target = (uint32_t) _pair_target;
enum reloc_type_generic type = _type;
check(instruction);
require_action(length == 2, finish, rval = KERN_FAILURE);
if (pcrel) {
target = target + base_pc - link_pc;
}
instr_addr = (uint32_t *) ((void *) instruction);
instr_data = *instr_addr;
#if !KERNEL
if (swap) {
instr_data = OSSwapInt32(instr_data);
}
#endif
rval = check_for_direct_pure_virtual_call(relocator, instr_data);
require_noerr(rval, finish);
switch (type) {
case GENERIC_RELOC_VANILLA:
instr_data += target;
break;
case GENERIC_RELOC_SECTDIFF:
case GENERIC_RELOC_LOCAL_SECTDIFF:
instr_data = instr_data + target - pair_target;
break;
case GENERIC_RELOC_PB_LA_PTR:
rval = KERN_FAILURE;
goto finish;
case GENERIC_RELOC_PAIR:
default:
rval = KERN_FAILURE;
goto finish;
}
#if !KERNEL
if (swap) {
instr_data = OSSwapInt32(instr_data);
}
#endif
*instr_addr = instr_data;
rval = KERN_SUCCESS;
finish:
return rval;
}
#endif /* KXLD_USER_OR_I386 */
#if KXLD_USER_OR_X86_64
/*******************************************************************************
*******************************************************************************/
static boolean_t
x86_64_reloc_has_pair(u_int _type)
{
enum reloc_type_x86_64 type = _type;
return type == X86_64_RELOC_SUBTRACTOR;
}
/*******************************************************************************
*******************************************************************************/
static u_int
x86_64_reloc_get_pair_type(u_int _prev_type __unused)
{
return X86_64_RELOC_UNSIGNED;
}
/*******************************************************************************
*******************************************************************************/
static boolean_t
x86_64_reloc_has_got(u_int _type)
{
enum reloc_type_x86_64 type = _type;
return type == X86_64_RELOC_GOT_LOAD || type == X86_64_RELOC_GOT;
}
/*******************************************************************************
*******************************************************************************/
static kern_return_t
x86_64_process_reloc(const KXLDRelocator *relocator __unused, u_char *instruction,
u_int length, u_int pcrel, kxld_addr_t _base_pc __unused,
kxld_addr_t _link_pc, kxld_addr_t _link_disp, u_int _type,
kxld_addr_t _target, kxld_addr_t _pair_target, boolean_t swap __unused)
{
kern_return_t rval = KERN_FAILURE;
enum reloc_type_x86_64 type = _type;
int32_t *instr32p = NULL;
int32_t instr32 = 0;
uint64_t *instr64p = NULL;
uint64_t instr64 = 0;
uint64_t target = _target;
uint64_t pair_target = _pair_target;
uint64_t link_pc = (uint64_t) _link_pc;
uint64_t link_disp = (uint64_t) _link_disp;
uint64_t adjustment = 0;
check(instruction);
require_action(length == 2 || length == 3,
finish, rval = KERN_FAILURE);
if (length == 2) {
instr32p = (int32_t *) ((void *) instruction);
instr32 = *instr32p;
#if !KERNEL
if (swap) {
instr32 = OSSwapInt32(instr32);
}
#endif
rval = check_for_direct_pure_virtual_call(relocator, instr32);
require_noerr(rval, finish);
/* There are a number of different small adjustments for pc-relative
* relocation entries. The general case is to subtract the size of the
* relocation (represented by the length parameter), and it applies to
* the GOT types and external SIGNED types. The non-external signed types
* have a different adjustment corresponding to the specific type.
*/
switch (type) {
case X86_64_RELOC_SIGNED:
if (pair_target) {
adjustment = 0;
break;
}
OS_FALLTHROUGH;
case X86_64_RELOC_SIGNED_1:
if (pair_target) {
adjustment = 1;
break;
}
OS_FALLTHROUGH;
case X86_64_RELOC_SIGNED_2:
if (pair_target) {
adjustment = 2;
break;
}
OS_FALLTHROUGH;
case X86_64_RELOC_SIGNED_4:
if (pair_target) {
adjustment = 4;
break;
}
OS_FALLTHROUGH;
case X86_64_RELOC_BRANCH:
case X86_64_RELOC_GOT:
case X86_64_RELOC_GOT_LOAD:
adjustment = (1 << length);
break;
default:
break;
}
/* Perform the actual relocation. All of the 32-bit relocations are
* pc-relative except for SUBTRACTOR, so a good chunk of the logic is
* stuck in calculate_displacement_x86_64. The signed relocations are
* a special case, because when they are non-external, the instruction
* already contains the pre-relocation displacement, so we only need to
* find the difference between how far the PC was relocated, and how
* far the target is relocated. Since the target variable already
* contains the difference between the target's base and link
* addresses, we add the difference between the PC's base and link
* addresses to the adjustment variable. This will yield the
* appropriate displacement in calculate_displacement.
*/
switch (type) {
case X86_64_RELOC_BRANCH:
require_action(pcrel, finish, rval = KERN_FAILURE);
adjustment += link_pc;
break;
case X86_64_RELOC_SIGNED:
case X86_64_RELOC_SIGNED_1:
case X86_64_RELOC_SIGNED_2:
case X86_64_RELOC_SIGNED_4:
require_action(pcrel, finish, rval = KERN_FAILURE);
adjustment += (pair_target) ? (link_disp) : (link_pc);
break;
case X86_64_RELOC_GOT:
case X86_64_RELOC_GOT_LOAD:
require_action(pcrel, finish, rval = KERN_FAILURE);
adjustment += link_pc;
target = pair_target;
break;
case X86_64_RELOC_SUBTRACTOR:
require_action(!pcrel, finish, rval = KERN_FAILURE);
instr32 = (int32_t) (target - pair_target);
break;
case X86_64_RELOC_UNSIGNED:
default:
rval = KERN_FAILURE;
goto finish;
}
/* Call calculate_displacement for the pc-relative relocations */
if (pcrel) {
rval = calculate_displacement_x86_64(target, adjustment, &instr32);
require_noerr(rval, finish);
}
#if !KERNEL
if (swap) {
instr32 = OSSwapInt32(instr32);
}
#endif
*instr32p = instr32;
} else {
instr64p = (uint64_t *) ((void *) instruction);
instr64 = *instr64p;
#if !KERNEL
if (swap) {
instr64 = OSSwapInt64(instr64);
}
#endif
rval = check_for_direct_pure_virtual_call(relocator, (u_long) instr64);
require_noerr(rval, finish);
switch (type) {
case X86_64_RELOC_UNSIGNED:
require_action(!pcrel, finish, rval = KERN_FAILURE);
instr64 += target;
break;
case X86_64_RELOC_SUBTRACTOR:
require_action(!pcrel, finish, rval = KERN_FAILURE);
instr64 = target - pair_target;
break;
case X86_64_RELOC_SIGNED_1:
case X86_64_RELOC_SIGNED_2:
case X86_64_RELOC_SIGNED_4:
case X86_64_RELOC_GOT_LOAD:
case X86_64_RELOC_BRANCH:
case X86_64_RELOC_SIGNED:
case X86_64_RELOC_GOT:
default:
rval = KERN_FAILURE;
goto finish;
}
#if !KERNEL
if (swap) {
instr64 = OSSwapInt64(instr64);
}
#endif
*instr64p = instr64;
}
rval = KERN_SUCCESS;
finish:
return rval;
}
/*******************************************************************************
*******************************************************************************/
static kern_return_t
calculate_displacement_x86_64(uint64_t target, uint64_t adjustment,
int32_t *instr32)
{
kern_return_t rval = KERN_FAILURE;
int64_t displacement;
uint64_t difference;
displacement = *instr32 + target - adjustment;
difference = ABSOLUTE_VALUE(displacement);
require_action(difference < X86_64_RIP_RELATIVE_LIMIT, finish,
rval = KERN_FAILURE;
kxld_log(kKxldLogLinking, kKxldLogErr, kKxldLogRelocationOverflow));
*instr32 = (int32_t) displacement;
rval = KERN_SUCCESS;
finish:
return rval;
}
#endif /* KXLD_USER_OR_X86_64 */
#if KXLD_USER_OR_ARM
/*******************************************************************************
*******************************************************************************/
static boolean_t
arm_reloc_has_pair(u_int _type)
{
enum reloc_type_arm type = _type;
switch (type) {
case ARM_RELOC_SECTDIFF:
return TRUE;
default:
return FALSE;
}
return FALSE;
}
/*******************************************************************************
*******************************************************************************/
static u_int
arm_reloc_get_pair_type(u_int _prev_type __unused)
{
return ARM_RELOC_PAIR;
}
/*******************************************************************************
*******************************************************************************/
static boolean_t
arm_reloc_has_got(u_int _type __unused)
{
return FALSE;
}
/*******************************************************************************
*******************************************************************************/
static kern_return_t
arm_process_reloc(const KXLDRelocator *relocator __unused, u_char *instruction,
u_int length, u_int pcrel, kxld_addr_t _base_pc __unused,
kxld_addr_t _link_pc __unused, kxld_addr_t _link_disp __unused,
u_int _type __unused, kxld_addr_t _target __unused,
kxld_addr_t _pair_target __unused, boolean_t swap __unused)
{
kern_return_t rval = KERN_FAILURE;
uint32_t *instr_addr = NULL;
uint32_t instr_data = 0;
uint32_t base_pc = (uint32_t) _base_pc;
uint32_t link_pc = (uint32_t) _link_pc;
uint32_t target = (uint32_t) _target;
int32_t displacement = 0;
enum reloc_type_arm type = _type;
check(instruction);
require_action(length == 2, finish, rval = KERN_FAILURE);
if (pcrel) {
displacement = target + base_pc - link_pc;
}
instr_addr = (uint32_t *) ((void *) instruction);
instr_data = *instr_addr;
#if !KERNEL
if (swap) {
instr_data = OSSwapInt32(instr_data);
}
#endif
rval = check_for_direct_pure_virtual_call(relocator, instr_data);
require_noerr(rval, finish);
switch (type) {
case ARM_RELOC_VANILLA:
instr_data += target;
break;
/*
* If the displacement is 0 (the offset between the pc and the target has
* not changed), then we don't need to do anything for BR24 and BR22
* relocs. As it turns out, because kexts build with -mlong-calls all
* relocations currently end up being either vanilla (handled above) or
* BR22/BR24 with a displacement of 0.
* We could handle other displacements here but to keep things simple, we
* won't until it is needed (at which point the kernelcache will fail to
* link)
*/
case ARM_RELOC_BR24:
require_action(pcrel, finish, rval = KERN_FAILURE);
require_action(displacement == 0, finish, rval = KERN_FAILURE);
break;
case ARM_THUMB_RELOC_BR22:
require_action(pcrel, finish, rval = KERN_FAILURE);
require_action(displacement == 0, finish, rval = KERN_FAILURE);
break;
case ARM_RELOC_SECTDIFF:
case ARM_RELOC_LOCAL_SECTDIFF:
case ARM_RELOC_PB_LA_PTR:
rval = KERN_FAILURE;
goto finish;
case ARM_RELOC_PAIR:
default:
rval = KERN_FAILURE;
goto finish;
}
#if !KERNEL
if (swap) {
instr_data = OSSwapInt32(instr_data);
}
#endif
*instr_addr = instr_data;
rval = KERN_SUCCESS;
finish:
return rval;
}
#endif /* KXLD_USER_OR_ARM */
#if KXLD_USER_OR_ARM64
/*******************************************************************************
*******************************************************************************/
boolean_t
arm64_reloc_has_pair(u_int _type)
{
return _type == ARM64_RELOC_SUBTRACTOR;
}
/*******************************************************************************
*******************************************************************************/
u_int
arm64_reloc_get_pair_type(u_int _prev_type __unused)
{
if (_prev_type == ARM64_RELOC_SUBTRACTOR) {
return ARM64_RELOC_UNSIGNED;
} else {
return -1u;
}
}
/*******************************************************************************
*******************************************************************************/
boolean_t
arm64_reloc_has_got(u_int _type)
{
return _type == ARM64_RELOC_GOT_LOAD_PAGE21 ||
_type == ARM64_RELOC_GOT_LOAD_PAGEOFF12;
}
/*******************************************************************************
*******************************************************************************/
kern_return_t
arm64_process_reloc(const KXLDRelocator *relocator __unused, u_char *instruction,
u_int length, u_int pcrel, kxld_addr_t _base_pc __unused, kxld_addr_t _link_pc,
kxld_addr_t _link_disp __unused, u_int _type, kxld_addr_t _target,
kxld_addr_t _pair_target __unused, boolean_t swap)
{
kern_return_t rval = KERN_FAILURE;
enum reloc_type_arm64 type = _type;
uint64_t target = _target;
uint64_t link_pc = (uint64_t) _link_pc;
uint64_t difference = 0;
int64_t displacement = 0;
uint32_t addend = 0;
check(instruction);
require_action((length == 2 || length == 3), finish, rval = KERN_FAILURE);
if (length == 2) {
uint32_t *instr32p = (uint32_t *) (void *) instruction;
uint32_t instr32 = *instr32p;
#if !KERNEL
if (swap) {
instr32 = OSSwapInt32(instr32);
}
#endif
switch (type) {
case ARM64_RELOC_BRANCH26:
require_action(pcrel, finish, rval = KERN_FAILURE);
addend = (instr32 & 0x03FFFFFF) << 2;
addend = SIGN_EXTEND(addend, 27);
displacement = (target - link_pc + addend);
difference = ABSOLUTE_VALUE(displacement);
displacement = (displacement >> 2);
require_action(difference < (128 * 1024 * 1024), finish,
rval = KERN_FAILURE;
kxld_log(kKxldLogLinking, kKxldLogErr, kKxldLogRelocationOverflow));
instr32 = (instr32 & 0xFC000000) | (displacement & 0x03FFFFFF);
break;
default:
rval = KERN_FAILURE;
goto finish;
}
#if !KERNEL
if (swap) {
instr32 = OSSwapInt32(instr32);
}
#endif
*instr32p = instr32;
} else { /* length == 3 */
uint64_t *instr64p = (uint64_t *) (void *) instruction;
uint64_t instr64 = *instr64p;
#if !KERNEL
if (swap) {
instr64 = OSSwapInt64(instr64);
}
#endif
switch (type) {
case ARM64_RELOC_UNSIGNED:
require_action(!pcrel, finish, rval = KERN_FAILURE);
instr64 += target;
break;
default:
rval = KERN_FAILURE;
goto finish;
}
#if !KERNEL
if (swap) {
instr64 = OSSwapInt64(instr64);
}
#endif
*instr64p = instr64;
}
rval = KERN_SUCCESS;
finish:
return rval;
}
#endif /* KXLD_USER_OR_ARM64 */
Reference in a new issue Copy permalink