The following commit has been merged into the objtool/core branch of tip: Commit-ID: 1b4998c364bcfd7fe3442820b0f3064b1f7b3a77 Gitweb: https://git.kernel.org/tip/1b4998c364bcfd7fe3442820b0f3064b1f7b3a77 Author: Vasily Gorbik <gor@xxxxxxxxxxxxx> AuthorDate: Mon, 05 Oct 2020 17:50:38 +02:00 Committer: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> CommitterDate: Tue, 06 Oct 2020 09:36:57 -05:00 objtool: Fix x86 orc generation on big endian cross compiles Correct objtool orc generation endianness problems to enable fully functional x86 cross compiles on big endian hardware. Introduces bswap_if_needed macro which does a byte swap if target 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. Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx> Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> --- arch/x86/include/asm/orc_types.h | 10 ++++- tools/arch/x86/include/asm/orc_types.h | 10 ++++- tools/objtool/arch/x86/include/arch_endianness.h | 9 ++++- tools/objtool/check.c | 5 +- tools/objtool/endianness.h | 38 +++++++++++++++- tools/objtool/orc_dump.c | 5 +- tools/objtool/orc_gen.c | 3 +- tools/objtool/special.c | 6 +- 8 files changed, 80 insertions(+), 6 deletions(-) create mode 100644 tools/objtool/arch/x86/include/arch_endianness.h create mode 100644 tools/objtool/endianness.h diff --git a/arch/x86/include/asm/orc_types.h b/arch/x86/include/asm/orc_types.h index fdbffec..5a2baf2 100644 --- a/arch/x86/include/asm/orc_types.h +++ b/arch/x86/include/asm/orc_types.h @@ -40,6 +40,8 @@ #define ORC_REG_MAX 15 #ifndef __ASSEMBLY__ +#include <asm/byteorder.h> + /* * This struct is more or less a vastly simplified version of the DWARF Call * Frame Information standard. It contains only the necessary parts of DWARF @@ -51,10 +53,18 @@ struct orc_entry { s16 sp_offset; s16 bp_offset; +#if defined(__LITTLE_ENDIAN_BITFIELD) unsigned sp_reg:4; unsigned bp_reg:4; unsigned type:2; unsigned end:1; +#elif defined(__BIG_ENDIAN_BITFIELD) + unsigned bp_reg:4; + unsigned sp_reg:4; + unsigned unused:5; + unsigned end:1; + unsigned type:2; +#endif } __packed; #endif /* __ASSEMBLY__ */ diff --git a/tools/arch/x86/include/asm/orc_types.h b/tools/arch/x86/include/asm/orc_types.h index fdbffec..5a2baf2 100644 --- a/tools/arch/x86/include/asm/orc_types.h +++ b/tools/arch/x86/include/asm/orc_types.h @@ -40,6 +40,8 @@ #define ORC_REG_MAX 15 #ifndef __ASSEMBLY__ +#include <asm/byteorder.h> + /* * This struct is more or less a vastly simplified version of the DWARF Call * Frame Information standard. It contains only the necessary parts of DWARF @@ -51,10 +53,18 @@ struct orc_entry { s16 sp_offset; s16 bp_offset; +#if defined(__LITTLE_ENDIAN_BITFIELD) unsigned sp_reg:4; unsigned bp_reg:4; unsigned type:2; unsigned end:1; +#elif defined(__BIG_ENDIAN_BITFIELD) + unsigned bp_reg:4; + unsigned sp_reg:4; + unsigned unused:5; + unsigned end:1; + unsigned type:2; +#endif } __packed; #endif /* __ASSEMBLY__ */ diff --git a/tools/objtool/arch/x86/include/arch_endianness.h b/tools/objtool/arch/x86/include/arch_endianness.h new file mode 100644 index 0000000..7c36252 --- /dev/null +++ b/tools/objtool/arch/x86/include/arch_endianness.h @@ -0,0 +1,9 @@ +/* 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 */ diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 3d14134..f48430d 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -13,6 +13,7 @@ #include "special.h" #include "warn.h" #include "arch_elf.h" +#include "endianness.h" #include <linux/objtool.h> #include <linux/hashtable.h> @@ -1372,7 +1373,7 @@ static int read_unwind_hints(struct objtool_file *file) cfa = &insn->cfi.cfa; if (hint->type == UNWIND_HINT_TYPE_RET_OFFSET) { - insn->ret_offset = hint->sp_offset; + insn->ret_offset = bswap_if_needed(hint->sp_offset); continue; } @@ -1384,7 +1385,7 @@ static int read_unwind_hints(struct objtool_file *file) return -1; } - cfa->offset = hint->sp_offset; + cfa->offset = bswap_if_needed(hint->sp_offset); insn->cfi.type = hint->type; insn->cfi.end = hint->end; } diff --git a/tools/objtool/endianness.h b/tools/objtool/endianness.h new file mode 100644 index 0000000..ebece31 --- /dev/null +++ b/tools/objtool/endianness.h @@ -0,0 +1,38 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _OBJTOOL_ENDIANNESS_H +#define _OBJTOOL_ENDIANNESS_H + +#include <linux/kernel.h> +#include <endian.h> +#include "arch_endianness.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 + +/* + * Does a byte swap if target 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) \ +({ \ + __typeof__(val) __ret; \ + 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; \ + default: \ + BUILD_BUG(); break; \ + } \ + __ret; \ +}) + +#endif /* _OBJTOOL_ENDIANNESS_H */ diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c index 5e6a953..4e818a2 100644 --- a/tools/objtool/orc_dump.c +++ b/tools/objtool/orc_dump.c @@ -8,6 +8,7 @@ #include <asm/orc_types.h> #include "objtool.h" #include "warn.h" +#include "endianness.h" static const char *reg_name(unsigned int reg) { @@ -197,11 +198,11 @@ int orc_dump(const char *_objname) printf(" sp:"); - print_reg(orc[i].sp_reg, orc[i].sp_offset); + print_reg(orc[i].sp_reg, bswap_if_needed(orc[i].sp_offset)); printf(" bp:"); - print_reg(orc[i].bp_reg, orc[i].bp_offset); + print_reg(orc[i].bp_reg, bswap_if_needed(orc[i].bp_offset)); printf(" type:%s end:%d\n", orc_type_name(orc[i].type), orc[i].end); diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c index 235663b..134d786 100644 --- a/tools/objtool/orc_gen.c +++ b/tools/objtool/orc_gen.c @@ -11,6 +11,7 @@ #include "check.h" #include "warn.h" +#include "endianness.h" int create_orc(struct objtool_file *file) { @@ -96,6 +97,8 @@ static int create_orc_entry(struct elf *elf, struct section *u_sec, struct secti /* populate ORC data */ orc = (struct orc_entry *)u_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); /* populate reloc for ip */ reloc = malloc(sizeof(*reloc)); diff --git a/tools/objtool/special.c b/tools/objtool/special.c index 1a2420f..ab7cb1e 100644 --- a/tools/objtool/special.c +++ b/tools/objtool/special.c @@ -15,6 +15,7 @@ #include "special.h" #include "warn.h" #include "arch_special.h" +#include "endianness.h" struct special_entry { const char *sec; @@ -77,8 +78,9 @@ static int get_alt_entry(struct elf *elf, struct special_entry *entry, if (entry->feature) { unsigned short feature; - feature = *(unsigned short *)(sec->data->d_buf + offset + - entry->feature); + feature = bswap_if_needed(*(unsigned short *)(sec->data->d_buf + + offset + + entry->feature)); arch_handle_alternative(feature, alt); }
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