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objtool: Use target file endianness instead of a compiled constant

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Some architectures like powerpc support both endianness, it's
therefore not possible to fix the endianness via arch/endianness.h
because there is no easy way to get the target endianness at
build time.

Use the endianness recorded in the file objtool is working on.

Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221114175754.1131267-10-sv@linux.ibm.com
This commit is contained in:
Christophe Leroy 2022-11-14 23:27:47 +05:30 committed by Michael Ellerman
parent efb11fdb3e
commit 0646c28b41
6 changed files with 30 additions and 31 deletions
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9
tools/objtool/arch/x86/include/arch/endianness.h
View File

@ -1,9 +0,0 @@
/* SPDX-License-Identifier: GPL-2.0-or-later */
#ifndef _ARCH_ENDIANNESS_H
#define _ARCH_ENDIANNESS_H
#include <endian.h>
#define __TARGET_BYTE_ORDER __LITTLE_ENDIAN
#endif /* _ARCH_ENDIANNESS_H */

2
tools/objtool/check.c
View File

@ -2100,7 +2100,7 @@ static int read_unwind_hints(struct objtool_file *file)
return -1;
}
cfi.cfa.offset = bswap_if_needed(hint->sp_offset);
cfi.cfa.offset = bswap_if_needed(file->elf, hint->sp_offset);
cfi.type = hint->type;
cfi.end = hint->end;

32
tools/objtool/include/objtool/endianness.h
View File

@ -2,33 +2,33 @@
#ifndef _OBJTOOL_ENDIANNESS_H
#define _OBJTOOL_ENDIANNESS_H
#include <arch/endianness.h>
#include <linux/kernel.h>
#include <endian.h>
#ifndef __TARGET_BYTE_ORDER
#error undefined arch __TARGET_BYTE_ORDER
#endif
#if __BYTE_ORDER != __TARGET_BYTE_ORDER
#define __NEED_BSWAP 1
#else
#define __NEED_BSWAP 0
#endif
#include <objtool/elf.h>
/*
* Does a byte swap if target endianness doesn't match the host, i.e. cross
* Does a byte swap if target file endianness doesn't match the host, i.e. cross
* compilation for little endian on big endian and vice versa.
* To be used for multi-byte values conversion, which are read from / about
* to be written to a target native endianness ELF file.
*/
#define bswap_if_needed(val) \
static inline bool need_bswap(struct elf *elf)
{
return (__BYTE_ORDER == __LITTLE_ENDIAN) ^
(elf->ehdr.e_ident[EI_DATA] == ELFDATA2LSB);
}
#define bswap_if_needed(elf, val) \
({ \
__typeof__(val) __ret; \
bool __need_bswap = need_bswap(elf); \
switch (sizeof(val)) { \
case 8: __ret = __NEED_BSWAP ? bswap_64(val) : (val); break; \
case 4: __ret = __NEED_BSWAP ? bswap_32(val) : (val); break; \
case 2: __ret = __NEED_BSWAP ? bswap_16(val) : (val); break; \
case 8: \
__ret = __need_bswap ? bswap_64(val) : (val); break; \
case 4: \
__ret = __need_bswap ? bswap_32(val) : (val); break; \
case 2: \
__ret = __need_bswap ? bswap_16(val) : (val); break; \
default: \
BUILD_BUG(); break; \
} \

11
tools/objtool/orc_dump.c
View File

@ -76,6 +76,7 @@ int orc_dump(const char *_objname)
GElf_Rela rela;
GElf_Sym sym;
Elf_Data *data, *symtab = NULL, *rela_orc_ip = NULL;
struct elf dummy_elf = {};
objname = _objname;
@ -94,6 +95,12 @@ int orc_dump(const char *_objname)
return -1;
}
if (!elf64_getehdr(elf)) {
WARN_ELF("elf64_getehdr");
return -1;
}
memcpy(&dummy_elf.ehdr, elf64_getehdr(elf), sizeof(dummy_elf.ehdr));
if (elf_getshdrnum(elf, &nr_sections)) {
WARN_ELF("elf_getshdrnum");
return -1;
@ -198,11 +205,11 @@ int orc_dump(const char *_objname)
printf(" sp:");
print_reg(orc[i].sp_reg, bswap_if_needed(orc[i].sp_offset));
print_reg(orc[i].sp_reg, bswap_if_needed(&dummy_elf, orc[i].sp_offset));
printf(" bp:");
print_reg(orc[i].bp_reg, bswap_if_needed(orc[i].bp_offset));
print_reg(orc[i].bp_reg, bswap_if_needed(&dummy_elf, orc[i].bp_offset));
printf(" type:%s end:%d\n",
orc_type_name(orc[i].type), orc[i].end);

4
tools/objtool/orc_gen.c
View File

@ -97,8 +97,8 @@ static int write_orc_entry(struct elf *elf, struct section *orc_sec,
/* populate ORC data */
orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
memcpy(orc, o, sizeof(*orc));
orc->sp_offset = bswap_if_needed(orc->sp_offset);
orc->bp_offset = bswap_if_needed(orc->bp_offset);
orc->sp_offset = bswap_if_needed(elf, orc->sp_offset);
orc->bp_offset = bswap_if_needed(elf, orc->bp_offset);
/* populate reloc for ip */
if (elf_add_reloc_to_insn(elf, ip_sec, idx * sizeof(int), R_X86_64_PC32,

3
tools/objtool/special.c
View File

@ -87,7 +87,8 @@ static int get_alt_entry(struct elf *elf, struct special_entry *entry,
if (entry->feature) {
unsigned short feature;
feature = bswap_if_needed(*(unsigned short *)(sec->data->d_buf +
feature = bswap_if_needed(elf,
*(unsigned short *)(sec->data->d_buf +
offset +
entry->feature));
arch_handle_alternative(feature, alt);