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Date:   Wed, 30 Sep 2020 11:58:31 +0200
From:   Vasily Gorbik <gor@linux.ibm.com>
To:     Josh Poimboeuf <jpoimboe@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>
Cc:     Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
        Miroslav Benes <mbenes@suse.cz>,
        Alexandre Chartre <alexandre.chartre@oracle.com>,
        Julien Thierry <jthierry@redhat.com>,
        linux-kernel@vger.kernel.org
Subject: [RFC PATCH 2/2] objtool: fix x86 orc generation on big endian cross
 compiles
Message-ID: <patch-2.thread-e6a24b.git-e6a24bf796d2.your-ad-here.call-01601459756-ext-4914@work.hours>
References: <cover.thread-e6a24b.your-ad-here.call-01601459756-ext-4914@work.hours>
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Precedence: bulk

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

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
---
 arch/x86/include/asm/orc_types.h       | 24 ++++++++++++++++++++++++
 tools/arch/x86/include/asm/orc_types.h | 24 ++++++++++++++++++++++++
 tools/objtool/orc_dump.c               |  4 ++--
 tools/objtool/orc_gen.c                |  2 ++
 4 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/orc_types.h b/arch/x86/include/asm/orc_types.h
index d25534940bde..931f99b70af3 100644
--- a/arch/x86/include/asm/orc_types.h
+++ b/arch/x86/include/asm/orc_types.h
@@ -61,6 +61,13 @@
 #define UNWIND_HINT_TYPE_RET_OFFSET	3
 
 #ifndef __ASSEMBLY__
+#ifdef __KERNEL__
+#include <linux/swab.h>
+#include <asm/byteorder.h>
+#else
+#include <endian.h>
+#endif
+
 /*
  * 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
@@ -69,6 +76,9 @@
  * the stack for a given code address.  Each instance of the struct corresponds
  * to one or more code locations.
  */
+#if defined(__BYTE_ORDER) ? \
+	__BYTE_ORDER == __LITTLE_ENDIAN : defined(__LITTLE_ENDIAN)
+
 struct orc_entry {
 	s16		sp_offset;
 	s16		bp_offset;
@@ -78,6 +88,20 @@ struct orc_entry {
 	unsigned	end:1;
 } __packed;
 
+#else
+
+struct orc_entry {
+	s16		sp_offset;
+	s16		bp_offset;
+	unsigned	bp_reg:4;
+	unsigned	sp_reg:4;
+	unsigned	unused:5;
+	unsigned	end:1;
+	unsigned	type:2;
+} __packed;
+
+#endif
+
 /*
  * This struct is used by asm and inline asm code to manually annotate the
  * location of registers on the stack for the ORC unwinder.
diff --git a/tools/arch/x86/include/asm/orc_types.h b/tools/arch/x86/include/asm/orc_types.h
index d25534940bde..931f99b70af3 100644
--- a/tools/arch/x86/include/asm/orc_types.h
+++ b/tools/arch/x86/include/asm/orc_types.h
@@ -61,6 +61,13 @@
 #define UNWIND_HINT_TYPE_RET_OFFSET	3
 
 #ifndef __ASSEMBLY__
+#ifdef __KERNEL__
+#include <linux/swab.h>
+#include <asm/byteorder.h>
+#else
+#include <endian.h>
+#endif
+
 /*
  * 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
@@ -69,6 +76,9 @@
  * the stack for a given code address.  Each instance of the struct corresponds
  * to one or more code locations.
  */
+#if defined(__BYTE_ORDER) ? \
+	__BYTE_ORDER == __LITTLE_ENDIAN : defined(__LITTLE_ENDIAN)
+
 struct orc_entry {
 	s16		sp_offset;
 	s16		bp_offset;
@@ -78,6 +88,20 @@ struct orc_entry {
 	unsigned	end:1;
 } __packed;
 
+#else
+
+struct orc_entry {
+	s16		sp_offset;
+	s16		bp_offset;
+	unsigned	bp_reg:4;
+	unsigned	sp_reg:4;
+	unsigned	unused:5;
+	unsigned	end:1;
+	unsigned	type:2;
+} __packed;
+
+#endif
+
 /*
  * This struct is used by asm and inline asm code to manually annotate the
  * location of registers on the stack for the ORC unwinder.
diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c
index fca46e006fc2..0fbf8521c891 100644
--- a/tools/objtool/orc_dump.c
+++ b/tools/objtool/orc_dump.c
@@ -196,11 +196,11 @@ 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)le16toh(orc[i].sp_offset));
 
 		printf(" bp:");
 
-		print_reg(orc[i].bp_reg, orc[i].bp_offset);
+		print_reg(orc[i].bp_reg, (s16)le16toh(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 968f55e6dd94..b3978fad93e6 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -90,6 +90,8 @@ 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 = htole16(orc->sp_offset);
+	orc->bp_offset = htole16(orc->bp_offset);
 
 	/* populate reloc for ip */
 	reloc = malloc(sizeof(*reloc));
-- 
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