[RFC PATCH v3 4/4] objtool: fix x86 orc generation on big endian cross compiles

From: Vasily Gorbik
Date: Wed Sep 30 2020 - 18:17:56 EST


Correct objtool orc generation endianness problems to enable fully
functional x86 cross compiles on big endian hardware.

Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
---
arch/x86/include/asm/orc_types.h | 10 ++++++++++
tools/arch/x86/include/asm/orc_types.h | 10 ++++++++++
tools/objtool/arch/x86/special.c | 2 +-
tools/objtool/check.c | 4 ++--
tools/objtool/orc_dump.c | 4 ++--
tools/objtool/orc_gen.c | 2 ++
6 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/orc_types.h b/arch/x86/include/asm/orc_types.h
index fdbffec4cfde..5a2baf28a1dc 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 fdbffec4cfde..5a2baf28a1dc 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/special.c b/tools/objtool/arch/x86/special.c
index fd4af88c0ea5..8349842aac82 100644
--- a/tools/objtool/arch/x86/special.c
+++ b/tools/objtool/arch/x86/special.c
@@ -9,7 +9,7 @@

void arch_handle_alternative(unsigned short feature, struct special_alt *alt)
{
- switch (feature) {
+ switch (le16_to_cpu(feature)) {
case X86_FEATURE_SMAP:
/*
* If UACCESS validation is enabled; force that alternative;
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 2df9f769412e..f20a4be2fb22 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1370,7 +1370,7 @@ 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 = le16_to_cpu(hint->sp_offset);
continue;
}

@@ -1382,7 +1382,7 @@ static int read_unwind_hints(struct objtool_file *file)
return -1;
}

- cfa->offset = hint->sp_offset;
+ cfa->offset = le16_to_cpu(hint->sp_offset);
insn->cfi.type = hint->type;
insn->cfi.end = hint->end;
}
diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c
index 5e6a95368d35..4cea20520ca7 100644
--- a/tools/objtool/orc_dump.c
+++ b/tools/objtool/orc_dump.c
@@ -197,11 +197,11 @@ int orc_dump(const char *_objname)

printf(" sp:");

- print_reg(orc[i].sp_reg, orc[i].sp_offset);
+ print_reg(orc[i].sp_reg, (s16)le16_to_cpu(orc[i].sp_offset));

printf(" bp:");

- print_reg(orc[i].bp_reg, orc[i].bp_offset);
+ print_reg(orc[i].bp_reg, (s16)le16_to_cpu(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 235663b96adc..123fd718ea9a 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -96,6 +96,8 @@ 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 = cpu_to_le16(orc->sp_offset);
+ orc->bp_offset = cpu_to_le16(orc->bp_offset);

/* populate reloc for ip */
reloc = malloc(sizeof(*reloc));
--
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