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

madvenka@linux.microsoft.com posted 20 patches 2 months, 3 weeks ago
[RFC PATCH v2 05/20] objtool: Reorganize ORC types
Posted by madvenka@linux.microsoft.com 2 months, 3 weeks ago
From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>

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
Re: [RFC PATCH v2 05/20] objtool: Reorganize ORC types
Posted by Chen Zhongjin 2 months, 3 weeks ago

On 2022/5/24 8:16, madvenka@linux.microsoft.com wrote:
> From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>
> 
> 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.
...
> 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;
Are sp_reg & fp_reg & end needed? I noticed that they are not used in
reliability checking.

> +	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 */
Re: [RFC PATCH v2 05/20] objtool: Reorganize ORC types
Posted by Madhavan T. Venkataraman 2 months, 3 weeks ago
See my responses inline...

On 5/24/22 09:27, Chen Zhongjin wrote:
> 
> 
> On 2022/5/24 8:16, madvenka@linux.microsoft.com wrote:
>> From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>
>>
>> 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.
> ...
>> 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;
> Are sp_reg & fp_reg & end needed? I noticed that they are not used in
> reliability checking.

Yeah. The ORC entry structure is a superset of what I need for ARM64. But X86 requires all of it.
(Although I think "end" is not needed anymore).

And, other architectures might require all of it. So, I am keeping it as is.

> 
>> +	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 */

Thanks!

Madhavan