[RFC PATCH v2 05/20] objtool: Reorganize ORC types

madvenka
2022-05-24T00:17:27Z

The ORC code needs to be reorganized into arch-specific and generic parts
so that architectures other than X86 can use the generic parts.

orc_types.h contains the following ORC definitions shared between objtool
and the kernel:

- ORC register definitions which are arch-specific.
- orc_entry structure which is generic.

Move orc_entry into a new file include/linux/orc_entry.h. Also, the field
names bp_reg and bp_offset in struct orc_entry are x86-specific. Change
them to fp_reg and fp_offset. FP stands for frame pointer.

Currently, the type field in orc_entry is only 2 bits. For other
architectures, we will need more. So, expand this to 3 bits.

Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
---
arch/x86/include/asm/orc_types.h | 37 +++++-------------------
include/linux/orc_entry.h | 39 ++++++++++++++++++++++++++
tools/arch/x86/include/asm/orc_types.h | 37 +++++-------------------
tools/include/linux/orc_entry.h | 39 ++++++++++++++++++++++++++
tools/objtool/orc_gen.c | 4 +--
tools/objtool/sync-check.sh | 1 +
6 files changed, 95 insertions(+), 62 deletions(-)
create mode 100644 include/linux/orc_entry.h
create mode 100644 tools/include/linux/orc_entry.h

diff --git a/arch/x86/include/asm/orc_types.h b/arch/x86/include/asm/orc_types.h
index 5a2baf28a1dc..851c9fb9f695 100644
--- a/arch/x86/include/asm/orc_types.h
+++ b/arch/x86/include/asm/orc_types.h
@@ -8,6 +8,13 @@

#include <linux/types.h>
#include <linux/compiler.h>
+#include <linux/orc_entry.h>
+
+/*
+ * For x86, use the appripriate name for the frame pointer in orc_entry.
+ */
+#define bp_offset fp_offset
+#define bp_reg fp_reg

/*
* The ORC_REG_* registers are base registers which are used to find other
@@ -39,34 +46,4 @@
#define ORC_REG_SP_INDIRECT 9
#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
- * CFI, simplified for ease of access by the in-kernel unwinder. It tells the
- * unwinder how to find the previous SP and BP (and sometimes entry regs) on
- * the stack for a given code address. Each instance of the struct corresponds
- * to one or more code locations.
- */
-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__ */
-
#endif /* _ORC_TYPES_H */
diff --git a/include/linux/orc_entry.h b/include/linux/orc_entry.h
new file mode 100644
index 000000000000..3d49e3b9dabe
--- /dev/null
+++ b/include/linux/orc_entry.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#ifndef _ORC_ENTRY_H
+#define _ORC_ENTRY_H
+
+#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
+ * CFI, simplified for ease of access by the in-kernel unwinder. It tells the
+ * unwinder how to find the previous SP and BP (and sometimes entry regs) on
+ * the stack for a given code address. Each instance of the struct corresponds
+ * to one or more code locations.
+ */
+struct orc_entry {
+ s16 sp_offset;
+ s16 fp_offset;
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+ unsigned sp_reg:4;
+ unsigned fp_reg:4;
+ unsigned type:3;
+ unsigned end:1;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+ unsigned fp_reg:4;
+ unsigned sp_reg:4;
+ unsigned unused:4;
+ unsigned end:1;
+ unsigned type:3;
+#endif
+} __packed;
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ORC_ENTRY_H */
diff --git a/tools/arch/x86/include/asm/orc_types.h b/tools/arch/x86/include/asm/orc_types.h
index 5a2baf28a1dc..851c9fb9f695 100644
--- a/tools/arch/x86/include/asm/orc_types.h
+++ b/tools/arch/x86/include/asm/orc_types.h
@@ -8,6 +8,13 @@

#include <linux/types.h>
#include <linux/compiler.h>
+#include <linux/orc_entry.h>
+
+/*
+ * For x86, use the appripriate name for the frame pointer in orc_entry.
+ */
+#define bp_offset fp_offset
+#define bp_reg fp_reg

/*
* The ORC_REG_* registers are base registers which are used to find other
@@ -39,34 +46,4 @@
#define ORC_REG_SP_INDIRECT 9
#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
- * CFI, simplified for ease of access by the in-kernel unwinder. It tells the
- * unwinder how to find the previous SP and BP (and sometimes entry regs) on
- * the stack for a given code address. Each instance of the struct corresponds
- * to one or more code locations.
- */
-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__ */
-
#endif /* _ORC_TYPES_H */
diff --git a/tools/include/linux/orc_entry.h b/tools/include/linux/orc_entry.h
new file mode 100644
index 000000000000..3d49e3b9dabe
--- /dev/null
+++ b/tools/include/linux/orc_entry.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#ifndef _ORC_ENTRY_H
+#define _ORC_ENTRY_H
+
+#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
+ * CFI, simplified for ease of access by the in-kernel unwinder. It tells the
+ * unwinder how to find the previous SP and BP (and sometimes entry regs) on
+ * the stack for a given code address. Each instance of the struct corresponds
+ * to one or more code locations.
+ */
+struct orc_entry {
+ s16 sp_offset;
+ s16 fp_offset;
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+ unsigned sp_reg:4;
+ unsigned fp_reg:4;
+ unsigned type:3;
+ unsigned end:1;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+ unsigned fp_reg:4;
+ unsigned sp_reg:4;
+ unsigned unused:4;
+ unsigned end:1;
+ unsigned type:3;
+#endif
+} __packed;
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ORC_ENTRY_H */
diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index dd3c64af9db2..68c317daadbf 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -98,7 +98,7 @@ static int write_orc_entry(struct elf *elf, struct section *orc_sec,
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->fp_offset = bswap_if_needed(orc->fp_offset);

/* populate reloc for ip */
if (elf_add_reloc_to_insn(elf, ip_sec, idx * sizeof(int), R_X86_64_PC32,
@@ -149,7 +149,7 @@ int orc_create(struct objtool_file *file)

struct orc_entry null = {
.sp_reg = ORC_REG_UNDEFINED,
- .bp_reg = ORC_REG_UNDEFINED,
+ .fp_reg = ORC_REG_UNDEFINED,
.type = UNWIND_HINT_TYPE_CALL,
};

diff --git a/tools/objtool/sync-check.sh b/tools/objtool/sync-check.sh
index ee49b4e9e72c..ef1acb064605 100755
--- a/tools/objtool/sync-check.sh
+++ b/tools/objtool/sync-check.sh
@@ -18,6 +18,7 @@ arch/x86/include/asm/unwind_hints.h
arch/x86/lib/x86-opcode-map.txt
arch/x86/tools/gen-insn-attr-x86.awk
include/linux/static_call_types.h
+include/linux/orc_entry.h
"

SYNC_CHECK_FILES='
--
2.25.1