[PATCH bpf-next 0/7] bpf: btf: fix struct/union/fwd types with kind_flag

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Revision v1 of 3 in this series.

8 messages, 1 author, 2018-12-12 · open the first message on its own page

[PATCH bpf-next 0/7] bpf: btf: fix struct/union/fwd types with kind_flag

From: Yonghong Song <hidden>
Date: 2018-12-12 00:46:36 

Commit 69b693f0aefa ("bpf: btf: Introduce BPF Type Format (BTF)")
introduced BTF, a debug info format for BTF.

The original design has a couple of issues though.
First, the bitfield size is only encoded in int type.
If the struct member bitfield type is enum, pahole ([1])
or llvm is forced to replace enum with int type. As a result, the original
type information gets lost.

Second, the original BTF design does not envision the possibility of
BTF=>header_file conversion ([2]), hence does not encode "struct" or
"union" info for a forward type. Such information is necessary to
convert BTF to a header file.

This patch set fixed the issue by introducing kind_flag, using one bit
in type->info. When kind_flag, the struct/union btf_member->offset
will encode both bitfield_size and bit_offset, covering both
int and enum base types. The kind_flag is also used to indicate whether
the forward type is a union (when set) or a struct.

Please see each individual patches for details.

[1] https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=b18354f64cc215368c3bc0df4a7e5341c55c378c
[2] https://lwn.net/SubscriberLink/773198/fe3074838f5c3f26/

Yonghong Song (7):
  bpf: btf: refactor btf_int_bits_seq_show()
  bpf: btf: fix struct/union/fwd types with kind_flag
  tools/bpf: sync btf.h header from kernel to tools
  tools/bpf: add test_btf unit tests for kind_flag
  tools/bpf: test kernel bpffs map pretty print with struct kind_flag
  tools: bpftool: refactor btf_dumper_int_bits()
  tools: bpftool: support pretty print with kind_flag set

 include/uapi/linux/btf.h               |  15 +-
 kernel/bpf/btf.c                       | 266 +++++++++--
 tools/bpf/bpftool/btf_dumper.c         |  58 ++-
 tools/include/uapi/linux/btf.h         |  15 +-
 tools/testing/selftests/bpf/test_btf.c | 593 ++++++++++++++++++++++++-
 5 files changed, 881 insertions(+), 66 deletions(-)

-- 
2.17.1

[PATCH bpf-next 1/7] bpf: btf: refactor btf_int_bits_seq_show()

From: Yonghong Song <hidden>
Date: 2018-12-12 00:46:36 

Refactor function btf_int_bits_seq_show() by creating
function btf_bitfield_seq_show() which has no dependence
on btf and btf_type. The function btf_bitfield_seq_show()
will be in later patch to directly dump bitfield member values.

Signed-off-by: Yonghong Song <redacted>
---
 kernel/bpf/btf.c | 35 +++++++++++++++++++++--------------
 1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index bf34933cc413..ed5ac131c046 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -1038,26 +1038,16 @@ static void btf_int_log(struct btf_verifier_env *env,
 			 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
 }
 
-static void btf_int_bits_seq_show(const struct btf *btf,
-				  const struct btf_type *t,
-				  void *data, u8 bits_offset,
-				  struct seq_file *m)
+static void btf_bitfield_seq_show(void *data, u8 bits_offset,
+				  u8 nr_bits, struct seq_file *m)
 {
 	u16 left_shift_bits, right_shift_bits;
-	u32 int_data = btf_type_int(t);
-	u8 nr_bits = BTF_INT_BITS(int_data);
-	u8 total_bits_offset;
 	u8 nr_copy_bytes;
 	u8 nr_copy_bits;
 	u64 print_num;
 
-	/*
-	 * bits_offset is at most 7.
-	 * BTF_INT_OFFSET() cannot exceed 64 bits.
-	 */
-	total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
-	data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
-	bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
+	data += BITS_ROUNDDOWN_BYTES(bits_offset);
+	bits_offset = BITS_PER_BYTE_MASKED(bits_offset);
 	nr_copy_bits = nr_bits + bits_offset;
 	nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
 
@@ -1077,6 +1067,23 @@ static void btf_int_bits_seq_show(const struct btf *btf,
 	seq_printf(m, "0x%llx", print_num);
 }
 
+static void btf_int_bits_seq_show(const struct btf *btf,
+				  const struct btf_type *t,
+				  void *data, u8 bits_offset,
+				  struct seq_file *m)
+{
+	u32 int_data = btf_type_int(t);
+	u8 nr_bits = BTF_INT_BITS(int_data);
+	u8 total_bits_offset;
+
+	/*
+	 * bits_offset is at most 7.
+	 * BTF_INT_OFFSET() cannot exceed 64 bits.
+	 */
+	total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
+	btf_bitfield_seq_show(data, total_bits_offset, nr_bits, m);
+}
+
 static void btf_int_seq_show(const struct btf *btf, const struct btf_type *t,
 			     u32 type_id, void *data, u8 bits_offset,
 			     struct seq_file *m)
-- 
2.17.1

[PATCH bpf-next 3/7] tools/bpf: sync btf.h header from kernel to tools

From: Yonghong Song <hidden>
Date: 2018-12-12 00:46:37 

Sync include/uapi/linux/btf.h to tools/include/uapi/linux/btf.h.

Signed-off-by: Yonghong Song <redacted>
---
 tools/include/uapi/linux/btf.h | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/tools/include/uapi/linux/btf.h b/tools/include/uapi/linux/btf.h
index 14f66948fc95..34aba40ed926 100644
--- a/tools/include/uapi/linux/btf.h
+++ b/tools/include/uapi/linux/btf.h
@@ -34,7 +34,9 @@ struct btf_type {
 	 * bits  0-15: vlen (e.g. # of struct's members)
 	 * bits 16-23: unused
 	 * bits 24-27: kind (e.g. int, ptr, array...etc)
-	 * bits 28-31: unused
+	 * bits 28-30: unused
+	 * bit     31: kind_flag, currently used by
+	 *             struct, union and fwd
 	 */
 	__u32 info;
 	/* "size" is used by INT, ENUM, STRUCT and UNION.
@@ -52,6 +54,7 @@ struct btf_type {
 
 #define BTF_INFO_KIND(info)	(((info) >> 24) & 0x0f)
 #define BTF_INFO_VLEN(info)	((info) & 0xffff)
+#define BTF_INFO_KFLAG(info)	((info) >> 31)
 
 #define BTF_KIND_UNKN		0	/* Unknown	*/
 #define BTF_KIND_INT		1	/* Integer	*/
@@ -110,9 +113,17 @@ struct btf_array {
 struct btf_member {
 	__u32	name_off;
 	__u32	type;
-	__u32	offset;	/* offset in bits */
+	__u32	offset;	/* [bitfield_size and] offset in bits */
 };
 
+/* If the type info kind_flag set, the btf_member.offset
+ * contains both member bit offset and bitfield size, and
+ * bitfield size will set for struct/union bitfield members.
+ * Otherwise, it contains only bit offset.
+ */
+#define BTF_MEMBER_BITFIELD_SIZE(val)	((val) >> 24)
+#define BTF_MEMBER_BIT_OFFSET(val)	((val) & 0xffffff)
+
 /* BTF_KIND_FUNC_PROTO is followed by multiple "struct btf_param".
  * The exact number of btf_param is stored in the vlen (of the
  * info in "struct btf_type").
-- 
2.17.1

[PATCH bpf-next 4/7] tools/bpf: add test_btf unit tests for kind_flag

From: Yonghong Song <hidden>
Date: 2018-12-12 00:46:39 

This patch added unit tests for different types handling
type->info.kind_flag. The following new tests are added:
  $ test_btf
  ...
  BTF raw test[82] (invalid int kind_flag): OK
  BTF raw test[83] (invalid ptr kind_flag): OK
  BTF raw test[84] (invalid array kind_flag): OK
  BTF raw test[85] (invalid enum kind_flag): OK
  BTF raw test[86] (valid fwd kind_flag): OK
  BTF raw test[87] (invalid typedef kind_flag): OK
  BTF raw test[88] (invalid volatile kind_flag): OK
  BTF raw test[89] (invalid const kind_flag): OK
  BTF raw test[90] (invalid restrict kind_flag): OK
  BTF raw test[91] (invalid func kind_flag): OK
  BTF raw test[92] (invalid func_proto kind_flag): OK
  BTF raw test[93] (valid struct kind_flag, bitfield_size = 0): OK
  BTF raw test[94] (valid struct kind_flag, int member, bitfield_size != 0): OK
  BTF raw test[95] (valid union kind_flag, int member, bitfield_size != 0): OK
  BTF raw test[96] (valid struct kind_flag, enum member, bitfield_size != 0): OK
  BTF raw test[97] (valid union kind_flag, enum member, bitfield_size != 0): OK
  BTF raw test[98] (valid struct kind_flag, typedef member, bitfield_size != 0): OK
  BTF raw test[99] (valid union kind_flag, typedef member, bitfield_size != 0): OK
  BTF raw test[100] (invalid struct type, bitfield_size greater than struct size): OK
  BTF raw test[101] (invalid union type, bitfield_size greater than struct size): OK
  ...
  PASS:120 SKIP:0 FAIL:0

The second parameter name of macro
  BTF_INFO_ENC(kind, root, vlen)
in selftests test_btf.c is also renamed from "root" to "kind_flag".
Note that before this patch "root" is not used and always 0.

Signed-off-by: Yonghong Song <redacted>
---
 tools/testing/selftests/bpf/test_btf.c | 426 ++++++++++++++++++++++++-
 1 file changed, 424 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/test_btf.c b/tools/testing/selftests/bpf/test_btf.c
index f570e0a39959..e4483cc9ca98 100644
--- a/tools/testing/selftests/bpf/test_btf.c
+++ b/tools/testing/selftests/bpf/test_btf.c
@@ -65,8 +65,8 @@ static int __base_pr(const char *format, ...)
 	return err;
 }
 
-#define BTF_INFO_ENC(kind, root, vlen)			\
-	((!!(root) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
+#define BTF_INFO_ENC(kind, kind_flag, vlen)			\
+	((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
 
 #define BTF_TYPE_ENC(name, info, size_or_type)	\
 	(name), (info), (size_or_type)
@@ -86,6 +86,8 @@ static int __base_pr(const char *format, ...)
 #define BTF_MEMBER_ENC(name, type, bits_offset)	\
 	(name), (type), (bits_offset)
 #define BTF_ENUM_ENC(name, val) (name), (val)
+#define BTF_MEMBER_OFFSET(bitfield_size, bits_offset) \
+	((bitfield_size) << 24 | (bits_offset))
 
 #define BTF_TYPEDEF_ENC(name, type) \
 	BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_TYPEDEF, 0, 0), type)
@@ -2215,6 +2217,426 @@ static struct btf_raw_test raw_tests[] = {
 	.err_str = "Invalid type_id",
 },
 
+{
+	.descr = "invalid int kind_flag",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_INT, 1, 0), 4),	/* [2] */
+		BTF_INT_ENC(0, 0, 32),
+		BTF_END_RAW,
+	},
+	.str_sec = "",
+	.str_sec_size = sizeof(""),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "int_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid btf_info kind_flag",
+},
+
+{
+	.descr = "invalid ptr kind_flag",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 1, 0), 1),	/* [2] */
+		BTF_END_RAW,
+	},
+	.str_sec = "",
+	.str_sec_size = sizeof(""),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "ptr_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid btf_info kind_flag",
+},
+
+{
+	.descr = "invalid array kind_flag",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_ARRAY, 1, 0), 0),	/* [2] */
+		BTF_ARRAY_ENC(1, 1, 1),
+		BTF_END_RAW,
+	},
+	.str_sec = "",
+	.str_sec_size = sizeof(""),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "array_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid btf_info kind_flag",
+},
+
+{
+	.descr = "invalid enum kind_flag",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_ENUM, 1, 1), 4),	/* [2] */
+		BTF_ENUM_ENC(NAME_TBD, 0),
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A",
+	.str_sec_size = sizeof("\0A"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "enum_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid btf_info kind_flag",
+},
+
+{
+	.descr = "valid fwd kind_flag",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(NAME_TBD,
+			     BTF_INFO_ENC(BTF_KIND_FWD, 1, 0), 0),	/* [2] */
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A",
+	.str_sec_size = sizeof("\0A"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "fwd_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+},
+
+{
+	.descr = "invalid typedef kind_flag",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(NAME_TBD,
+			     BTF_INFO_ENC(BTF_KIND_TYPEDEF, 1, 0), 1),	/* [2] */
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A",
+	.str_sec_size = sizeof("\0A"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "typedef_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid btf_info kind_flag",
+},
+
+{
+	.descr = "invalid volatile kind_flag",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),			/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_VOLATILE, 1, 0), 1),	/* [2] */
+		BTF_END_RAW,
+	},
+	.str_sec = "",
+	.str_sec_size = sizeof(""),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "volatile_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid btf_info kind_flag",
+},
+
+{
+	.descr = "invalid const kind_flag",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_CONST, 1, 0), 1),	/* [2] */
+		BTF_END_RAW,
+	},
+	.str_sec = "",
+	.str_sec_size = sizeof(""),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "const_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid btf_info kind_flag",
+},
+
+{
+	.descr = "invalid restrict kind_flag",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),			/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_RESTRICT, 1, 0), 1),	/* [2] */
+		BTF_END_RAW,
+	},
+	.str_sec = "",
+	.str_sec_size = sizeof(""),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "restrict_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid btf_info kind_flag",
+},
+
+{
+	.descr = "invalid func kind_flag",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),			/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 0), 0),	/* [2] */
+		BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_FUNC, 1, 0), 2),	/* [3] */
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A",
+	.str_sec_size = sizeof("\0A"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "func_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid btf_info kind_flag",
+},
+
+{
+	.descr = "invalid func_proto kind_flag",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),			/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 1, 0), 0),	/* [2] */
+		BTF_END_RAW,
+	},
+	.str_sec = "",
+	.str_sec_size = sizeof(""),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "func_proto_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid btf_info kind_flag",
+},
+
+{
+	.descr = "valid struct kind_flag, bitfield_size = 0",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),			/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_STRUCT, 1, 2), 8),	/* [2] */
+		BTF_MEMBER_ENC(NAME_TBD, 1, BTF_MEMBER_OFFSET(0, 0)),
+		BTF_MEMBER_ENC(NAME_TBD, 1, BTF_MEMBER_OFFSET(0, 32)),
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A\0B",
+	.str_sec_size = sizeof("\0A\0B"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "struct_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+},
+
+{
+	.descr = "valid struct kind_flag, int member, bitfield_size != 0",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),			/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_STRUCT, 1, 2), 4),	/* [2] */
+		BTF_MEMBER_ENC(NAME_TBD, 1, BTF_MEMBER_OFFSET(4, 0)),
+		BTF_MEMBER_ENC(NAME_TBD, 1, BTF_MEMBER_OFFSET(4, 4)),
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A\0B",
+	.str_sec_size = sizeof("\0A\0B"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "struct_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+},
+
+{
+	.descr = "valid union kind_flag, int member, bitfield_size != 0",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_UNION, 1, 2), 4),	/* [2] */
+		BTF_MEMBER_ENC(NAME_TBD, 1, BTF_MEMBER_OFFSET(4, 0)),
+		BTF_MEMBER_ENC(NAME_TBD, 1, BTF_MEMBER_OFFSET(4, 0)),
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A\0B",
+	.str_sec_size = sizeof("\0A\0B"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "union_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+},
+
+{
+	.descr = "valid struct kind_flag, enum member, bitfield_size != 0",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1), 4),	/* [2] */
+		BTF_ENUM_ENC(NAME_TBD, 0),
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_STRUCT, 1, 2), 4),/* [3] */
+		BTF_MEMBER_ENC(NAME_TBD, 2, BTF_MEMBER_OFFSET(4, 0)),
+		BTF_MEMBER_ENC(NAME_TBD, 2, BTF_MEMBER_OFFSET(4, 4)),
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A\0B\0C",
+	.str_sec_size = sizeof("\0A\0B\0C"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "struct_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+},
+
+{
+	.descr = "valid union kind_flag, enum member, bitfield_size != 0",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1), 4),	/* [2] */
+		BTF_ENUM_ENC(NAME_TBD, 0),
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_UNION, 1, 2), 4),	/* [3] */
+		BTF_MEMBER_ENC(NAME_TBD, 2, BTF_MEMBER_OFFSET(4, 0)),
+		BTF_MEMBER_ENC(NAME_TBD, 2, BTF_MEMBER_OFFSET(4, 0)),
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A\0B\0C",
+	.str_sec_size = sizeof("\0A\0B\0C"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "union_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+},
+
+{
+	.descr = "valid struct kind_flag, typedef member, bitfield_size != 0",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1), 4),	/* [2] */
+		BTF_ENUM_ENC(NAME_TBD, 0),
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_STRUCT, 1, 2), 4),/* [3] */
+		BTF_MEMBER_ENC(NAME_TBD, 4, BTF_MEMBER_OFFSET(4, 0)),
+		BTF_MEMBER_ENC(NAME_TBD, 5, BTF_MEMBER_OFFSET(4, 4)),
+		BTF_TYPEDEF_ENC(NAME_TBD, 1),				/* [4] */
+		BTF_TYPEDEF_ENC(NAME_TBD, 2),				/* [5] */
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A\0B\0C\0D\0E",
+	.str_sec_size = sizeof("\0A\0B\0C\0D\0E"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "struct_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+},
+
+{
+	.descr = "valid union kind_flag, typedef member, bitfield_size != 0",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1), 4),	/* [2] */
+		BTF_ENUM_ENC(NAME_TBD, 0),
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_UNION, 1, 2), 4),	/* [3] */
+		BTF_MEMBER_ENC(NAME_TBD, 4, BTF_MEMBER_OFFSET(4, 0)),
+		BTF_MEMBER_ENC(NAME_TBD, 5, BTF_MEMBER_OFFSET(4, 0)),
+		BTF_TYPEDEF_ENC(NAME_TBD, 1),				/* [4] */
+		BTF_TYPEDEF_ENC(NAME_TBD, 2),				/* [5] */
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A\0B\0C\0D\0E",
+	.str_sec_size = sizeof("\0A\0B\0C\0D\0E"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "union_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+},
+
+{
+	.descr = "invalid struct type, bitfield_size greater than struct size",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),			/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_STRUCT, 1, 2), 4),	/* [2] */
+		BTF_MEMBER_ENC(NAME_TBD, 1, BTF_MEMBER_OFFSET(20, 0)),
+		BTF_MEMBER_ENC(NAME_TBD, 1, BTF_MEMBER_OFFSET(20, 20)),
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A\0B",
+	.str_sec_size = sizeof("\0A\0B"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "struct_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Member exceeds struct_size",
+},
+
+{
+	.descr = "invalid union type, bitfield_size greater than struct size",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_UNION, 1, 2), 2),	/* [2] */
+		BTF_MEMBER_ENC(NAME_TBD, 1, BTF_MEMBER_OFFSET(8, 0)),
+		BTF_MEMBER_ENC(NAME_TBD, 1, BTF_MEMBER_OFFSET(20, 0)),
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A\0B",
+	.str_sec_size = sizeof("\0A\0B"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "union_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Member exceeds struct_size",
+},
+
 }; /* struct btf_raw_test raw_tests[] */
 
 static const char *get_next_str(const char *start, const char *end)
-- 
2.17.1

[PATCH bpf-next 5/7] tools/bpf: test kernel bpffs map pretty print with struct kind_flag

From: Yonghong Song <hidden>
Date: 2018-12-12 00:46:41 

The new tests are added to test bpffs map pretty print in kernel with kind_flag
for structure type.

  $ test_btf -p
  ......
  BTF pretty print array(#1)......OK
  BTF pretty print array(#2)......OK
  PASS:8 SKIP:0 FAIL:0

Signed-off-by: Yonghong Song <redacted>
---
 tools/testing/selftests/bpf/test_btf.c | 167 +++++++++++++++++++++++--
 1 file changed, 155 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/bpf/test_btf.c b/tools/testing/selftests/bpf/test_btf.c
index e4483cc9ca98..4500a9cd2bcc 100644
--- a/tools/testing/selftests/bpf/test_btf.c
+++ b/tools/testing/selftests/bpf/test_btf.c
@@ -3458,7 +3458,8 @@ struct pprint_mapv {
 	} aenum;
 };
 
-static struct btf_raw_test pprint_test_template = {
+static struct btf_raw_test pprint_test_template[] = {
+{
 	.raw_types = {
 		/* unsighed char */			/* [1] */
 		BTF_TYPE_INT_ENC(NAME_TBD, 0, 0, 8, 1),
@@ -3515,6 +3516,136 @@ static struct btf_raw_test pprint_test_template = {
 	.key_type_id = 3,	/* unsigned int */
 	.value_type_id = 16,	/* struct pprint_mapv */
 	.max_entries = 128 * 1024,
+},
+
+{
+	/* this type will have the same type as the
+	 * first .raw_types definition, but struct type will
+	 * be encoded with kind_flag set.
+	 */
+	.raw_types = {
+		/* unsighed char */			/* [1] */
+		BTF_TYPE_INT_ENC(NAME_TBD, 0, 0, 8, 1),
+		/* unsigned short */			/* [2] */
+		BTF_TYPE_INT_ENC(NAME_TBD, 0, 0, 16, 2),
+		/* unsigned int */			/* [3] */
+		BTF_TYPE_INT_ENC(NAME_TBD, 0, 0, 32, 4),
+		/* int */				/* [4] */
+		BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4),
+		/* unsigned long long */		/* [5] */
+		BTF_TYPE_INT_ENC(NAME_TBD, 0, 0, 64, 8),
+		BTF_TYPE_INT_ENC(0, 0, 0, 32, 4),	/* [6] */
+		BTF_TYPE_INT_ENC(0, 0, 0, 32, 4),	/* [7] */
+		/* uint8_t[8] */			/* [8] */
+		BTF_TYPE_ARRAY_ENC(9, 1, 8),
+		/* typedef unsigned char uint8_t */	/* [9] */
+		BTF_TYPEDEF_ENC(NAME_TBD, 1),
+		/* typedef unsigned short uint16_t */	/* [10] */
+		BTF_TYPEDEF_ENC(NAME_TBD, 2),
+		/* typedef unsigned int uint32_t */	/* [11] */
+		BTF_TYPEDEF_ENC(NAME_TBD, 3),
+		/* typedef int int32_t */		/* [12] */
+		BTF_TYPEDEF_ENC(NAME_TBD, 4),
+		/* typedef unsigned long long uint64_t *//* [13] */
+		BTF_TYPEDEF_ENC(NAME_TBD, 5),
+		/* union (anon) */			/* [14] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_UNION, 0, 2), 8),
+		BTF_MEMBER_ENC(NAME_TBD, 13, 0),/* uint64_t ui64; */
+		BTF_MEMBER_ENC(NAME_TBD, 8, 0),	/* uint8_t ui8a[8]; */
+		/* enum (anon) */			/* [15] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_ENUM, 0, 4), 4),
+		BTF_ENUM_ENC(NAME_TBD, 0),
+		BTF_ENUM_ENC(NAME_TBD, 1),
+		BTF_ENUM_ENC(NAME_TBD, 2),
+		BTF_ENUM_ENC(NAME_TBD, 3),
+		/* struct pprint_mapv */		/* [16] */
+		BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_STRUCT, 1, 8), 32),
+		BTF_MEMBER_ENC(NAME_TBD, 11, BTF_MEMBER_OFFSET(0, 0)),	/* uint32_t ui32 */
+		BTF_MEMBER_ENC(NAME_TBD, 10, BTF_MEMBER_OFFSET(0, 32)),	/* uint16_t ui16 */
+		BTF_MEMBER_ENC(NAME_TBD, 12, BTF_MEMBER_OFFSET(0, 64)),	/* int32_t si32 */
+		BTF_MEMBER_ENC(NAME_TBD, 6, BTF_MEMBER_OFFSET(2, 96)),	/* unused_bits2a */
+		BTF_MEMBER_ENC(NAME_TBD, 7, BTF_MEMBER_OFFSET(28, 98)),	/* bits28 */
+		BTF_MEMBER_ENC(NAME_TBD, 6, BTF_MEMBER_OFFSET(2, 126)),	/* unused_bits2b */
+		BTF_MEMBER_ENC(0, 14, BTF_MEMBER_OFFSET(0, 128)),	/* union (anon) */
+		BTF_MEMBER_ENC(NAME_TBD, 15, BTF_MEMBER_OFFSET(0, 192)),	/* aenum */
+		BTF_END_RAW,
+	},
+	.str_sec = "\0unsigned char\0unsigned short\0unsigned int\0int\0unsigned long long\0uint8_t\0uint16_t\0uint32_t\0int32_t\0uint64_t\0ui64\0ui8a\0ENUM_ZERO\0ENUM_ONE\0ENUM_TWO\0ENUM_THREE\0pprint_mapv\0ui32\0ui16\0si32\0unused_bits2a\0bits28\0unused_bits2b\0aenum",
+	.str_sec_size = sizeof("\0unsigned char\0unsigned short\0unsigned int\0int\0unsigned long long\0uint8_t\0uint16_t\0uint32_t\0int32_t\0uint64_t\0ui64\0ui8a\0ENUM_ZERO\0ENUM_ONE\0ENUM_TWO\0ENUM_THREE\0pprint_mapv\0ui32\0ui16\0si32\0unused_bits2a\0bits28\0unused_bits2b\0aenum"),
+	.key_size = sizeof(unsigned int),
+	.value_size = sizeof(struct pprint_mapv),
+	.key_type_id = 3,	/* unsigned int */
+	.value_type_id = 16,	/* struct pprint_mapv */
+	.max_entries = 128 * 1024,
+},
+
+{
+	/* this type will have the same layout as the
+	 * first .raw_types definition. The struct type will
+	 * be encoded with kind_flag set, bitfield members
+	 * are added typedef/const/volatile, and bitfield members
+	 * will have both int and enum types.
+	 */
+	.raw_types = {
+		/* unsighed char */			/* [1] */
+		BTF_TYPE_INT_ENC(NAME_TBD, 0, 0, 8, 1),
+		/* unsigned short */			/* [2] */
+		BTF_TYPE_INT_ENC(NAME_TBD, 0, 0, 16, 2),
+		/* unsigned int */			/* [3] */
+		BTF_TYPE_INT_ENC(NAME_TBD, 0, 0, 32, 4),
+		/* int */				/* [4] */
+		BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4),
+		/* unsigned long long */		/* [5] */
+		BTF_TYPE_INT_ENC(NAME_TBD, 0, 0, 64, 8),
+		BTF_TYPE_INT_ENC(0, 0, 0, 32, 4),	/* [6] */
+		BTF_TYPE_INT_ENC(0, 0, 0, 32, 4),	/* [7] */
+		/* uint8_t[8] */			/* [8] */
+		BTF_TYPE_ARRAY_ENC(9, 1, 8),
+		/* typedef unsigned char uint8_t */	/* [9] */
+		BTF_TYPEDEF_ENC(NAME_TBD, 1),
+		/* typedef unsigned short uint16_t */	/* [10] */
+		BTF_TYPEDEF_ENC(NAME_TBD, 2),
+		/* typedef unsigned int uint32_t */	/* [11] */
+		BTF_TYPEDEF_ENC(NAME_TBD, 3),
+		/* typedef int int32_t */		/* [12] */
+		BTF_TYPEDEF_ENC(NAME_TBD, 4),
+		/* typedef unsigned long long uint64_t *//* [13] */
+		BTF_TYPEDEF_ENC(NAME_TBD, 5),
+		/* union (anon) */			/* [14] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_UNION, 0, 2), 8),
+		BTF_MEMBER_ENC(NAME_TBD, 13, 0),/* uint64_t ui64; */
+		BTF_MEMBER_ENC(NAME_TBD, 8, 0),	/* uint8_t ui8a[8]; */
+		/* enum (anon) */			/* [15] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_ENUM, 0, 4), 4),
+		BTF_ENUM_ENC(NAME_TBD, 0),
+		BTF_ENUM_ENC(NAME_TBD, 1),
+		BTF_ENUM_ENC(NAME_TBD, 2),
+		BTF_ENUM_ENC(NAME_TBD, 3),
+		/* struct pprint_mapv */		/* [16] */
+		BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_STRUCT, 1, 8), 32),
+		BTF_MEMBER_ENC(NAME_TBD, 11, BTF_MEMBER_OFFSET(0, 0)),	/* uint32_t ui32 */
+		BTF_MEMBER_ENC(NAME_TBD, 10, BTF_MEMBER_OFFSET(0, 32)),	/* uint16_t ui16 */
+		BTF_MEMBER_ENC(NAME_TBD, 12, BTF_MEMBER_OFFSET(0, 64)),	/* int32_t si32 */
+		BTF_MEMBER_ENC(NAME_TBD, 17, BTF_MEMBER_OFFSET(2, 96)),	/* unused_bits2a */
+		BTF_MEMBER_ENC(NAME_TBD, 7, BTF_MEMBER_OFFSET(28, 98)),	/* bits28 */
+		BTF_MEMBER_ENC(NAME_TBD, 19, BTF_MEMBER_OFFSET(2, 126)),/* unused_bits2b */
+		BTF_MEMBER_ENC(0, 14, BTF_MEMBER_OFFSET(0, 128)),	/* union (anon) */
+		BTF_MEMBER_ENC(NAME_TBD, 15, BTF_MEMBER_OFFSET(0, 192)),	/* aenum */
+		/* typedef unsigned int ___int */	/* [17] */
+		BTF_TYPEDEF_ENC(NAME_TBD, 18),
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_VOLATILE, 0, 0), 6),	/* [18] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_CONST, 0, 0), 15),	/* [19] */
+		BTF_END_RAW,
+	},
+	.str_sec = "\0unsigned char\0unsigned short\0unsigned int\0int\0unsigned long long\0uint8_t\0uint16_t\0uint32_t\0int32_t\0uint64_t\0ui64\0ui8a\0ENUM_ZERO\0ENUM_ONE\0ENUM_TWO\0ENUM_THREE\0pprint_mapv\0ui32\0ui16\0si32\0unused_bits2a\0bits28\0unused_bits2b\0aenum\0___int",
+	.str_sec_size = sizeof("\0unsigned char\0unsigned short\0unsigned int\0int\0unsigned long long\0uint8_t\0uint16_t\0uint32_t\0int32_t\0uint64_t\0ui64\0ui8a\0ENUM_ZERO\0ENUM_ONE\0ENUM_TWO\0ENUM_THREE\0pprint_mapv\0ui32\0ui16\0si32\0unused_bits2a\0bits28\0unused_bits2b\0aenum\0___int"),
+	.key_size = sizeof(unsigned int),
+	.value_size = sizeof(struct pprint_mapv),
+	.key_type_id = 3,	/* unsigned int */
+	.value_type_id = 16,	/* struct pprint_mapv */
+	.max_entries = 128 * 1024,
+},
+
 };
 
 static struct btf_pprint_test_meta {
@@ -3617,9 +3748,9 @@ static int check_line(const char *expected_line, int nexpected_line,
 }
 
 
-static int do_test_pprint(void)
+static int do_test_pprint(int test_num)
 {
-	const struct btf_raw_test *test = &pprint_test_template;
+	const struct btf_raw_test *test = &pprint_test_template[test_num];
 	struct bpf_create_map_attr create_attr = {};
 	bool ordered_map, lossless_map, percpu_map;
 	int err, ret, num_cpus, rounded_value_size;
@@ -3635,7 +3766,7 @@ static int do_test_pprint(void)
 	uint8_t *raw_btf;
 	ssize_t nread;
 
-	fprintf(stderr, "%s......", test->descr);
+	fprintf(stderr, "%s(#%d)......", test->descr, test_num);
 	raw_btf = btf_raw_create(&hdr_tmpl, test->raw_types,
 				 test->str_sec, test->str_sec_size,
 				 &raw_btf_size, NULL);
@@ -3828,15 +3959,27 @@ static int test_pprint(void)
 	unsigned int i;
 	int err = 0;
 
+	/* test various maps with the first test template */
 	for (i = 0; i < ARRAY_SIZE(pprint_tests_meta); i++) {
-		pprint_test_template.descr = pprint_tests_meta[i].descr;
-		pprint_test_template.map_type = pprint_tests_meta[i].map_type;
-		pprint_test_template.map_name = pprint_tests_meta[i].map_name;
-		pprint_test_template.ordered_map = pprint_tests_meta[i].ordered_map;
-		pprint_test_template.lossless_map = pprint_tests_meta[i].lossless_map;
-		pprint_test_template.percpu_map = pprint_tests_meta[i].percpu_map;
-
-		err |= count_result(do_test_pprint());
+		pprint_test_template[0].descr = pprint_tests_meta[i].descr;
+		pprint_test_template[0].map_type = pprint_tests_meta[i].map_type;
+		pprint_test_template[0].map_name = pprint_tests_meta[i].map_name;
+		pprint_test_template[0].ordered_map = pprint_tests_meta[i].ordered_map;
+		pprint_test_template[0].lossless_map = pprint_tests_meta[i].lossless_map;
+		pprint_test_template[0].percpu_map = pprint_tests_meta[i].percpu_map;
+
+		err |= count_result(do_test_pprint(0));
+	}
+
+	/* test rest test templates with the first map */
+	for (i = 1; i < ARRAY_SIZE(pprint_test_template); i++) {
+		pprint_test_template[i].descr = pprint_tests_meta[0].descr;
+		pprint_test_template[i].map_type = pprint_tests_meta[0].map_type;
+		pprint_test_template[i].map_name = pprint_tests_meta[0].map_name;
+		pprint_test_template[i].ordered_map = pprint_tests_meta[0].ordered_map;
+		pprint_test_template[i].lossless_map = pprint_tests_meta[0].lossless_map;
+		pprint_test_template[i].percpu_map = pprint_tests_meta[0].percpu_map;
+		err |= count_result(do_test_pprint(i));
 	}
 
 	return err;
-- 
2.17.1

[PATCH bpf-next 2/7] bpf: btf: fix struct/union/fwd types with kind_flag

From: Yonghong Song <hidden>
Date: 2018-12-12 00:46:41 

This patch fixed two issues with BTF. One is related to
struct/union bitfield encoding and the other is related to
forward type.

Issue #1 and solution:
======================

Current btf encoding of bitfield follows what pahole generates.
For each bitfield, pahole will duplicate the type chain and
put the bitfield size at the final int or enum type.
Since the BTF enum type cannot encode bit size,
pahole workarounds the issue by generating
an int type whenever the enum bit size is not 32.

For example,
  -bash-4.4$ cat t.c
  typedef int ___int;
  enum A { A1, A2, A3 };
  struct t {
    int a[5];
    ___int b:4;
    volatile enum A c:4;
  } g;
  -bash-4.4$ gcc -c -O2 -g t.c
The current kernel supports the following BTF encoding:
  $ pahole -JV t.o
  [1] TYPEDEF ___int type_id=2
  [2] INT int size=4 bit_offset=0 nr_bits=32 encoding=SIGNED
  [3] ENUM A size=4 vlen=3
        A1 val=0
        A2 val=1
        A3 val=2
  [4] STRUCT t size=24 vlen=3
        a type_id=5 bits_offset=0
        b type_id=9 bits_offset=160
        c type_id=11 bits_offset=164
  [5] ARRAY (anon) type_id=2 index_type_id=2 nr_elems=5
  [6] INT sizetype size=8 bit_offset=0 nr_bits=64 encoding=(none)
  [7] VOLATILE (anon) type_id=3
  [8] INT int size=1 bit_offset=0 nr_bits=4 encoding=(none)
  [9] TYPEDEF ___int type_id=8
  [10] INT (anon) size=1 bit_offset=0 nr_bits=4 encoding=SIGNED
  [11] VOLATILE (anon) type_id=10

Two issues are in the above:
  . by changing enum type to int, we lost the original
    type information and this will not be ideal later
    when we try to convert BTF to a header file.
  . the type duplication for bitfields will cause
    BTF bloat. Duplicated types cannot be deduplicated
    later if the bitfield size is different.

To fix this issue, this patch implemented a compatible
change for BTF struct type encoding:
  . the bit 31 of struct_type->info, previously reserved,
    now is used to indicate whether bitfield_size is
    encoded in btf_member or not.
  . if bit 31 of struct_type->info is set,
    btf_member->offset will encode like:
      bit 0 - 23: bit offset
      bit 24 - 31: bitfield size
    if bit 31 is not set, the old behavior is preserved:
      bit 0 - 31: bit offset

So if the struct contains a bit field, the maximum bit offset
will be reduced to (2^24 - 1) instead of MAX_UINT. The maximum
bitfield size will be 256 which is enough for today as maximum
bitfield in compiler can be 128 where int128 type is supported.

This kernel patch intends to support the new BTF encoding:
  $ pahole -JV t.o
  [1] TYPEDEF ___int type_id=2
  [2] INT int size=4 bit_offset=0 nr_bits=32 encoding=SIGNED
  [3] ENUM A size=4 vlen=3
        A1 val=0
        A2 val=1
        A3 val=2
  [4] STRUCT t kind_flag=1 size=24 vlen=3
        a type_id=5 bitfield_size=0 bits_offset=0
        b type_id=1 bitfield_size=4 bits_offset=160
        c type_id=7 bitfield_size=4 bits_offset=164
  [5] ARRAY (anon) type_id=2 index_type_id=2 nr_elems=5
  [6] INT sizetype size=8 bit_offset=0 nr_bits=64 encoding=(none)
  [7] VOLATILE (anon) type_id=3

Issue #2 and solution:
======================

Current forward type in BTF does not specify whether the original
type is struct or union. This will not work for type pretty print
and BTF-to-header-file conversion as struct/union must be specified.
  $ cat tt.c
  struct t;
  union u;
  int foo(struct t *t, union u *u) { return 0; }
  $ gcc -c -g -O2 tt.c
  $ pahole -JV tt.o
  [1] INT int size=4 bit_offset=0 nr_bits=32 encoding=SIGNED
  [2] FWD t type_id=0
  [3] PTR (anon) type_id=2
  [4] FWD u type_id=0
  [5] PTR (anon) type_id=4

To fix this issue, similar to issue #1, type->info bit 31
is used. If the bit is set, it is union type. Otherwise, it is
a struct type.

  $ pahole -JV tt.o
  [1] INT int size=4 bit_offset=0 nr_bits=32 encoding=SIGNED
  [2] FWD t kind_flag=0 type_id=0
  [3] PTR (anon) kind_flag=0 type_id=2
  [4] FWD u kind_flag=1 type_id=0
  [5] PTR (anon) kind_flag=0 type_id=4

Pahole/LLVM change:
===================

The new kind_flag functionality has been implemented in pahole
and llvm:
  https://github.com/yonghong-song/pahole/tree/bitfield
  https://github.com/yonghong-song/llvm/tree/bitfield

Note that pahole hasn't implemented func/func_proto kind
and .BTF.ext. So to print function signature with bpftool,
the llvm compiler should be used.

Fixes: 69b693f0aefa ("bpf: btf: Introduce BPF Type Format (BTF)")
Signed-off-by: Martin KaFai Lau <redacted>
Signed-off-by: Yonghong Song <redacted>
---
 include/uapi/linux/btf.h |  15 ++-
 kernel/bpf/btf.c         | 231 +++++++++++++++++++++++++++++++++++----
 2 files changed, 225 insertions(+), 21 deletions(-)

diff --git a/include/uapi/linux/btf.h b/include/uapi/linux/btf.h
index 14f66948fc95..34aba40ed926 100644
--- a/include/uapi/linux/btf.h
+++ b/include/uapi/linux/btf.h
@@ -34,7 +34,9 @@ struct btf_type {
 	 * bits  0-15: vlen (e.g. # of struct's members)
 	 * bits 16-23: unused
 	 * bits 24-27: kind (e.g. int, ptr, array...etc)
-	 * bits 28-31: unused
+	 * bits 28-30: unused
+	 * bit     31: kind_flag, currently used by
+	 *             struct, union and fwd
 	 */
 	__u32 info;
 	/* "size" is used by INT, ENUM, STRUCT and UNION.
@@ -52,6 +54,7 @@ struct btf_type {
 
 #define BTF_INFO_KIND(info)	(((info) >> 24) & 0x0f)
 #define BTF_INFO_VLEN(info)	((info) & 0xffff)
+#define BTF_INFO_KFLAG(info)	((info) >> 31)
 
 #define BTF_KIND_UNKN		0	/* Unknown	*/
 #define BTF_KIND_INT		1	/* Integer	*/
@@ -110,9 +113,17 @@ struct btf_array {
 struct btf_member {
 	__u32	name_off;
 	__u32	type;
-	__u32	offset;	/* offset in bits */
+	__u32	offset;	/* [bitfield_size and] offset in bits */
 };
 
+/* If the type info kind_flag set, the btf_member.offset
+ * contains both member bit offset and bitfield size, and
+ * bitfield size will set for struct/union bitfield members.
+ * Otherwise, it contains only bit offset.
+ */
+#define BTF_MEMBER_BITFIELD_SIZE(val)	((val) >> 24)
+#define BTF_MEMBER_BIT_OFFSET(val)	((val) & 0xffffff)
+
 /* BTF_KIND_FUNC_PROTO is followed by multiple "struct btf_param".
  * The exact number of btf_param is stored in the vlen (of the
  * info in "struct btf_type").
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index ed5ac131c046..1b54dba58cb0 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -164,7 +164,7 @@
 #define BITS_ROUNDUP_BYTES(bits) \
 	(BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
 
-#define BTF_INFO_MASK 0x0f00ffff
+#define BTF_INFO_MASK 0x8f00ffff
 #define BTF_INT_MASK 0x0fffffff
 #define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
 #define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
@@ -274,6 +274,10 @@ struct btf_kind_operations {
 			    const struct btf_type *struct_type,
 			    const struct btf_member *member,
 			    const struct btf_type *member_type);
+	int (*check_bitfield_member)(struct btf_verifier_env *env,
+				     const struct btf_type *struct_type,
+				     const struct btf_member *member,
+				     const struct btf_type *member_type);
 	void (*log_details)(struct btf_verifier_env *env,
 			    const struct btf_type *t);
 	void (*seq_show)(const struct btf *btf, const struct btf_type *t,
@@ -419,6 +423,25 @@ static u16 btf_type_vlen(const struct btf_type *t)
 	return BTF_INFO_VLEN(t->info);
 }
 
+static bool btf_type_kflag(const struct btf_type *t)
+{
+	return BTF_INFO_KFLAG(t->info);
+}
+
+static u32 btf_member_bit_offset(const struct btf_type *struct_type,
+			     const struct btf_member *member)
+{
+	return btf_type_kflag(struct_type) ? BTF_MEMBER_BIT_OFFSET(member->offset)
+					   : member->offset;
+}
+
+static u32 btf_member_bitfield_size(const struct btf_type *struct_type,
+				    const struct btf_member *member)
+{
+	return btf_type_kflag(struct_type) ? BTF_MEMBER_BITFIELD_SIZE(member->offset)
+					   : 0;
+}
+
 static u32 btf_type_int(const struct btf_type *t)
 {
 	return *(u32 *)(t + 1);
@@ -583,6 +606,7 @@ static void btf_verifier_log_member(struct btf_verifier_env *env,
 {
 	struct bpf_verifier_log *log = &env->log;
 	struct btf *btf = env->btf;
+	u32 offset, bitfield_size;
 	va_list args;
 
 	if (!bpf_verifier_log_needed(log))
@@ -597,9 +621,16 @@ static void btf_verifier_log_member(struct btf_verifier_env *env,
 	if (env->phase != CHECK_META)
 		btf_verifier_log_type(env, struct_type, NULL);
 
-	__btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
+	offset = btf_member_bit_offset(struct_type, member);
+	bitfield_size = btf_member_bitfield_size(struct_type, member);
+	if (btf_type_kflag(struct_type))
+		__btf_verifier_log(log, "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
+			   btf_name_by_offset(btf, member->name_off),
+			   member->type, bitfield_size, offset);
+	else
+		__btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
 			   btf_name_by_offset(btf, member->name_off),
-			   member->type, member->offset);
+			   member->type, offset);
 
 	if (fmt && *fmt) {
 		__btf_verifier_log(log, " ");
@@ -915,6 +946,16 @@ static int btf_df_check_member(struct btf_verifier_env *env,
 	return -EINVAL;
 }
 
+static int btf_df_check_bitfield_member(struct btf_verifier_env *env,
+					const struct btf_type *struct_type,
+					const struct btf_member *member,
+					const struct btf_type *member_type)
+{
+	btf_verifier_log_basic(env, struct_type,
+			       "Unsupported check_bitfield_member");
+	return -EINVAL;
+}
+
 static int btf_df_resolve(struct btf_verifier_env *env,
 			  const struct resolve_vertex *v)
 {
@@ -947,6 +988,7 @@ static int btf_int_check_member(struct btf_verifier_env *env,
 	}
 
 	struct_bits_off += BTF_INT_OFFSET(int_data);
+
 	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
 	nr_copy_bits = BTF_INT_BITS(int_data) +
 		BITS_PER_BYTE_MASKED(struct_bits_off);
@@ -967,6 +1009,45 @@ static int btf_int_check_member(struct btf_verifier_env *env,
 	return 0;
 }
 
+static int btf_int_check_bitfield_member(struct btf_verifier_env *env,
+					 const struct btf_type *struct_type,
+					 const struct btf_member *member,
+					 const struct btf_type *member_type)
+{
+	u32 struct_bits_off, bitfield_size, bytes_offset;
+	u32 int_data = btf_type_int(member_type);
+	u32 struct_size = struct_type->size;
+	u32 nr_copy_bits;
+
+	/* A regular int type is required for the bitfield member */
+	bitfield_size = BTF_MEMBER_BITFIELD_SIZE(member->offset);
+	if (!btf_type_int_is_regular(member_type) ||
+	    bitfield_size > BTF_INT_BITS(int_data)) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Invalid member base type");
+		return -EINVAL;
+	}
+
+	struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
+	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
+	nr_copy_bits = bitfield_size + BITS_PER_BYTE_MASKED(struct_bits_off);
+
+	if (nr_copy_bits > BITS_PER_U64) {
+		btf_verifier_log_member(env, struct_type, member,
+					"nr_copy_bits exceeds 64");
+		return -EINVAL;
+	}
+
+	if (struct_size < bytes_offset ||
+	    struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member exceeds struct_size");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static s32 btf_int_check_meta(struct btf_verifier_env *env,
 			      const struct btf_type *t,
 			      u32 meta_left)
@@ -986,6 +1067,11 @@ static s32 btf_int_check_meta(struct btf_verifier_env *env,
 		return -EINVAL;
 	}
 
+	if (btf_type_kflag(t)) {
+		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
+		return -EINVAL;
+	}
+
 	int_data = btf_type_int(t);
 	if (int_data & ~BTF_INT_MASK) {
 		btf_verifier_log_basic(env, t, "Invalid int_data:%x",
@@ -1067,6 +1153,7 @@ static void btf_bitfield_seq_show(void *data, u8 bits_offset,
 	seq_printf(m, "0x%llx", print_num);
 }
 
+
 static void btf_int_bits_seq_show(const struct btf *btf,
 				  const struct btf_type *t,
 				  void *data, u8 bits_offset,
@@ -1133,6 +1220,7 @@ static const struct btf_kind_operations int_ops = {
 	.check_meta = btf_int_check_meta,
 	.resolve = btf_df_resolve,
 	.check_member = btf_int_check_member,
+	.check_bitfield_member = btf_int_check_bitfield_member,
 	.log_details = btf_int_log,
 	.seq_show = btf_int_seq_show,
 };
@@ -1162,6 +1250,31 @@ static int btf_modifier_check_member(struct btf_verifier_env *env,
 							 resolved_type);
 }
 
+static int btf_modifier_check_bitfield_member(struct btf_verifier_env *env,
+					      const struct btf_type *struct_type,
+					      const struct btf_member *member,
+					      const struct btf_type *member_type)
+{
+	const struct btf_type *resolved_type;
+	u32 resolved_type_id = member->type;
+	struct btf_member resolved_member;
+	struct btf *btf = env->btf;
+
+	resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
+	if (!resolved_type) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Invalid member");
+		return -EINVAL;
+	}
+
+	resolved_member = *member;
+	resolved_member.type = resolved_type_id;
+
+	return btf_type_ops(resolved_type)->check_bitfield_member(env, struct_type,
+								  &resolved_member,
+								  resolved_type);
+}
+
 static int btf_ptr_check_member(struct btf_verifier_env *env,
 				const struct btf_type *struct_type,
 				const struct btf_member *member,
@@ -1197,6 +1310,11 @@ static int btf_ref_type_check_meta(struct btf_verifier_env *env,
 		return -EINVAL;
 	}
 
+	if (btf_type_kflag(t)) {
+		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
+		return -EINVAL;
+	}
+
 	if (!BTF_TYPE_ID_VALID(t->type)) {
 		btf_verifier_log_type(env, t, "Invalid type_id");
 		return -EINVAL;
@@ -1350,6 +1468,7 @@ static struct btf_kind_operations modifier_ops = {
 	.check_meta = btf_ref_type_check_meta,
 	.resolve = btf_modifier_resolve,
 	.check_member = btf_modifier_check_member,
+	.check_bitfield_member = btf_modifier_check_bitfield_member,
 	.log_details = btf_ref_type_log,
 	.seq_show = btf_modifier_seq_show,
 };
@@ -1358,6 +1477,7 @@ static struct btf_kind_operations ptr_ops = {
 	.check_meta = btf_ref_type_check_meta,
 	.resolve = btf_ptr_resolve,
 	.check_member = btf_ptr_check_member,
+	.check_bitfield_member = btf_df_check_bitfield_member,
 	.log_details = btf_ref_type_log,
 	.seq_show = btf_ptr_seq_show,
 };
@@ -1392,6 +1512,7 @@ static struct btf_kind_operations fwd_ops = {
 	.check_meta = btf_fwd_check_meta,
 	.resolve = btf_df_resolve,
 	.check_member = btf_df_check_member,
+	.check_bitfield_member = btf_df_check_bitfield_member,
 	.log_details = btf_ref_type_log,
 	.seq_show = btf_df_seq_show,
 };
@@ -1450,6 +1571,11 @@ static s32 btf_array_check_meta(struct btf_verifier_env *env,
 		return -EINVAL;
 	}
 
+	if (btf_type_kflag(t)) {
+		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
+		return -EINVAL;
+	}
+
 	if (t->size) {
 		btf_verifier_log_type(env, t, "size != 0");
 		return -EINVAL;
@@ -1573,6 +1699,7 @@ static struct btf_kind_operations array_ops = {
 	.check_meta = btf_array_check_meta,
 	.resolve = btf_array_resolve,
 	.check_member = btf_array_check_member,
+	.check_bitfield_member = btf_df_check_bitfield_member,
 	.log_details = btf_array_log,
 	.seq_show = btf_array_seq_show,
 };
@@ -1611,6 +1738,7 @@ static s32 btf_struct_check_meta(struct btf_verifier_env *env,
 	u32 meta_needed, last_offset;
 	struct btf *btf = env->btf;
 	u32 struct_size = t->size;
+	u32 offset;
 	u16 i;
 
 	meta_needed = btf_type_vlen(t) * sizeof(*member);
@@ -1652,7 +1780,8 @@ static s32 btf_struct_check_meta(struct btf_verifier_env *env,
 			return -EINVAL;
 		}
 
-		if (is_union && member->offset) {
+		offset = btf_member_bit_offset(t, member);
+		if (is_union && offset) {
 			btf_verifier_log_member(env, t, member,
 						"Invalid member bits_offset");
 			return -EINVAL;
@@ -1662,20 +1791,20 @@ static s32 btf_struct_check_meta(struct btf_verifier_env *env,
 		 * ">" instead of ">=" because the last member could be
 		 * "char a[0];"
 		 */
-		if (last_offset > member->offset) {
+		if (last_offset > offset) {
 			btf_verifier_log_member(env, t, member,
 						"Invalid member bits_offset");
 			return -EINVAL;
 		}
 
-		if (BITS_ROUNDUP_BYTES(member->offset) > struct_size) {
+		if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
 			btf_verifier_log_member(env, t, member,
 						"Member bits_offset exceeds its struct size");
 			return -EINVAL;
 		}
 
 		btf_verifier_log_member(env, t, member, NULL);
-		last_offset = member->offset;
+		last_offset = offset;
 	}
 
 	return meta_needed;
@@ -1705,9 +1834,14 @@ static int btf_struct_resolve(struct btf_verifier_env *env,
 
 		last_member_type = btf_type_by_id(env->btf,
 						  last_member_type_id);
-		err = btf_type_ops(last_member_type)->check_member(env, v->t,
-							last_member,
-							last_member_type);
+		if (btf_member_bitfield_size(v->t, last_member))
+			err = btf_type_ops(last_member_type)->check_bitfield_member(env, v->t,
+								last_member,
+								last_member_type);
+		else
+			err = btf_type_ops(last_member_type)->check_member(env, v->t,
+								last_member,
+								last_member_type);
 		if (err)
 			return err;
 	}
@@ -1729,9 +1863,14 @@ static int btf_struct_resolve(struct btf_verifier_env *env,
 			return env_stack_push(env, member_type, member_type_id);
 		}
 
-		err = btf_type_ops(member_type)->check_member(env, v->t,
-							      member,
-							      member_type);
+		if (btf_member_bitfield_size(v->t, member))
+			err = btf_type_ops(member_type)->check_bitfield_member(env, v->t,
+									       member,
+									       member_type);
+		else
+			err = btf_type_ops(member_type)->check_member(env, v->t,
+								      member,
+								      member_type);
 		if (err)
 			return err;
 	}
@@ -1759,17 +1898,26 @@ static void btf_struct_seq_show(const struct btf *btf, const struct btf_type *t,
 	for_each_member(i, t, member) {
 		const struct btf_type *member_type = btf_type_by_id(btf,
 								member->type);
-		u32 member_offset = member->offset;
-		u32 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
-		u8 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
 		const struct btf_kind_operations *ops;
+		u32 member_offset, bitfield_size;
+		u32 bytes_offset;
+		u8 bits8_offset;
 
 		if (i)
 			seq_puts(m, seq);
 
-		ops = btf_type_ops(member_type);
-		ops->seq_show(btf, member_type, member->type,
-			      data + bytes_offset, bits8_offset, m);
+		member_offset = btf_member_bit_offset(t, member);
+		bitfield_size = btf_member_bitfield_size(t, member);
+		if (bitfield_size) {
+			btf_bitfield_seq_show(data, member_offset,
+					      bitfield_size, m);
+		} else {
+			bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
+			bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
+			ops = btf_type_ops(member_type);
+			ops->seq_show(btf, member_type, member->type,
+				      data + bytes_offset, bits8_offset, m);
+		}
 	}
 	seq_puts(m, "}");
 }
@@ -1778,6 +1926,7 @@ static struct btf_kind_operations struct_ops = {
 	.check_meta = btf_struct_check_meta,
 	.resolve = btf_struct_resolve,
 	.check_member = btf_struct_check_member,
+	.check_bitfield_member = btf_df_check_bitfield_member,
 	.log_details = btf_struct_log,
 	.seq_show = btf_struct_seq_show,
 };
@@ -1807,6 +1956,32 @@ static int btf_enum_check_member(struct btf_verifier_env *env,
 	return 0;
 }
 
+static int btf_enum_check_bitfield_member(struct btf_verifier_env *env,
+					  const struct btf_type *struct_type,
+					  const struct btf_member *member,
+					  const struct btf_type *member_type)
+{
+	u32 struct_bits_off, bitfield_size, bytes_end, struct_size;
+
+	struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
+	bitfield_size = BTF_MEMBER_BITFIELD_SIZE(member->offset);
+	if (bitfield_size > sizeof(int) * BITS_PER_BYTE) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member invalid bitfield_size");
+		return -EINVAL;
+	}
+
+	struct_size = struct_type->size;
+	bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + bitfield_size);
+	if (struct_size < bytes_end) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member exceeds struct_size");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static s32 btf_enum_check_meta(struct btf_verifier_env *env,
 			       const struct btf_type *t,
 			       u32 meta_left)
@@ -1826,6 +2001,11 @@ static s32 btf_enum_check_meta(struct btf_verifier_env *env,
 		return -EINVAL;
 	}
 
+	if (btf_type_kflag(t)) {
+		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
+		return -EINVAL;
+	}
+
 	if (t->size != sizeof(int)) {
 		btf_verifier_log_type(env, t, "Expected size:%zu",
 				      sizeof(int));
@@ -1893,6 +2073,7 @@ static struct btf_kind_operations enum_ops = {
 	.check_meta = btf_enum_check_meta,
 	.resolve = btf_df_resolve,
 	.check_member = btf_enum_check_member,
+	.check_bitfield_member = btf_enum_check_bitfield_member,
 	.log_details = btf_enum_log,
 	.seq_show = btf_enum_seq_show,
 };
@@ -1915,6 +2096,11 @@ static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
 		return -EINVAL;
 	}
 
+	if (btf_type_kflag(t)) {
+		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
+		return -EINVAL;
+	}
+
 	btf_verifier_log_type(env, t, NULL);
 
 	return meta_needed;
@@ -1974,6 +2160,7 @@ static struct btf_kind_operations func_proto_ops = {
 	 * Hence, there is no btf_func_check_member().
 	 */
 	.check_member = btf_df_check_member,
+	.check_bitfield_member = btf_df_check_bitfield_member,
 	.log_details = btf_func_proto_log,
 	.seq_show = btf_df_seq_show,
 };
@@ -1993,6 +2180,11 @@ static s32 btf_func_check_meta(struct btf_verifier_env *env,
 		return -EINVAL;
 	}
 
+	if (btf_type_kflag(t)) {
+		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
+		return -EINVAL;
+	}
+
 	btf_verifier_log_type(env, t, NULL);
 
 	return 0;
@@ -2002,6 +2194,7 @@ static struct btf_kind_operations func_ops = {
 	.check_meta = btf_func_check_meta,
 	.resolve = btf_df_resolve,
 	.check_member = btf_df_check_member,
+	.check_bitfield_member = btf_df_check_bitfield_member,
 	.log_details = btf_ref_type_log,
 	.seq_show = btf_df_seq_show,
 };
-- 
2.17.1

[PATCH bpf-next 6/7] tools: bpftool: refactor btf_dumper_int_bits()

From: Yonghong Song <hidden>
Date: 2018-12-12 00:46:42 

The core dump funcitonality in btf_dumper_int_bits() is
refactored into a separate function btf_dumper_bitfield()
which will be used by the next patch.

Signed-off-by: Yonghong Song <redacted>
---
 tools/bpf/bpftool/btf_dumper.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c
index 2392ccdc918f..6474b7555e7a 100644
--- a/tools/bpf/bpftool/btf_dumper.c
+++ b/tools/bpf/bpftool/btf_dumper.c
@@ -73,20 +73,17 @@ static int btf_dumper_array(const struct btf_dumper *d, __u32 type_id,
 	return ret;
 }
 
-static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
+static void btf_dumper_bitfield(__u32 nr_bits, __u8 bit_offset,
 				const void *data, json_writer_t *jw,
 				bool is_plain_text)
 {
 	int left_shift_bits, right_shift_bits;
-	int nr_bits = BTF_INT_BITS(int_type);
-	int total_bits_offset;
 	int bytes_to_copy;
 	int bits_to_copy;
 	__u64 print_num;
 
-	total_bits_offset = bit_offset + BTF_INT_OFFSET(int_type);
-	data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
-	bit_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
+	data += BITS_ROUNDDOWN_BYTES(bit_offset);
+	bit_offset = BITS_PER_BYTE_MASKED(bit_offset);
 	bits_to_copy = bit_offset + nr_bits;
 	bytes_to_copy = BITS_ROUNDUP_BYTES(bits_to_copy);
 
@@ -109,6 +106,19 @@ static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
 		jsonw_printf(jw, "%llu", print_num);
 }
 
+
+static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
+				const void *data, json_writer_t *jw,
+				bool is_plain_text)
+{
+	int nr_bits = BTF_INT_BITS(int_type);
+	int total_bits_offset;
+
+	total_bits_offset = bit_offset + BTF_INT_OFFSET(int_type);
+	btf_dumper_bitfield(nr_bits, total_bits_offset, data, jw,
+			    is_plain_text);
+}
+
 static int btf_dumper_int(const struct btf_type *t, __u8 bit_offset,
 			  const void *data, json_writer_t *jw,
 			  bool is_plain_text)
-- 
2.17.1

[PATCH bpf-next 7/7] tools: bpftool: support pretty print with kind_flag set

From: Yonghong Song <hidden>
Date: 2018-12-12 00:46:44 

The following example shows map pretty print with structures
which include bitfield members.

  enum A { A1, A2, A3, A4, A5 };
  typedef enum A ___A;
  struct tmp_t {
       char a1:4;
       int  a2:4;
       int  :4;
       __u32 a3:4;
       int b;
       ___A b1:4;
       enum A b2:4;
  };
  struct bpf_map_def SEC("maps") tmpmap = {
       .type = BPF_MAP_TYPE_ARRAY,
       .key_size = sizeof(__u32),
       .value_size = sizeof(struct tmp_t),
       .max_entries = 1,
  };
  BPF_ANNOTATE_KV_PAIR(tmpmap, int, struct tmp_t);

and the following map update in the bpf program:

  key = 0;
  struct tmp_t t = {};
  t.a1 = 2;
  t.a2 = 4;
  t.a3 = 6;
  t.b = 7;
  t.b1 = 8;
  t.b2 = 10;
  bpf_map_update_elem(&tmpmap, &key, &t, 0);

With this patch, I am able to print out the map values
correctly with this patch:
bpftool map dump id 187
  [{
        "key": 0,
        "value": {
            "a1": 0x2,
            "a2": 0x4,
            "a3": 0x6,
            "b": 7,
            "b1": 0x8,
            "b2": 0xa
        }
    }
  ]

The following example shows forward type can be properly
printed in function prototype with modified tst_btf_haskv.c.

  struct t;
  union  u;

  __attribute__((noinline))
  static int test_long_fname_1(struct dummy_tracepoint_args *arg,
                               struct t *p1, union u *p2,
                               __u32 unused)
  ...
  int _dummy_tracepoint(struct dummy_tracepoint_args *arg) {
    return test_long_fname_1(arg, 0, 0);
  }

  $ bpftool p d xlated id 24
  ...
  int test_long_fname_1(struct dummy_tracepoint_args * arg,
                        struct t * p1, union u * p2,
                        __u32 unused)
  ...

Signed-off-by: Yonghong Song <redacted>
---
 tools/bpf/bpftool/btf_dumper.c | 36 +++++++++++++++++++++++++---------
 1 file changed, 27 insertions(+), 9 deletions(-)

diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c
index 6474b7555e7a..9a43e91135f7 100644
--- a/tools/bpf/bpftool/btf_dumper.c
+++ b/tools/bpf/bpftool/btf_dumper.c
@@ -190,6 +190,7 @@ static int btf_dumper_struct(const struct btf_dumper *d, __u32 type_id,
 	const struct btf_type *t;
 	struct btf_member *m;
 	const void *data_off;
+	int kind_flag;
 	int ret = 0;
 	int i, vlen;
 
@@ -197,18 +198,32 @@ static int btf_dumper_struct(const struct btf_dumper *d, __u32 type_id,
 	if (!t)
 		return -EINVAL;
 
+	kind_flag = BTF_INFO_KFLAG(t->info);
 	vlen = BTF_INFO_VLEN(t->info);
 	jsonw_start_object(d->jw);
 	m = (struct btf_member *)(t + 1);
 
 	for (i = 0; i < vlen; i++) {
-		data_off = data + BITS_ROUNDDOWN_BYTES(m[i].offset);
+		__u32 bit_offset = m[i].offset;
+		__u32 bitfield_size = 0;
+
+		if (kind_flag) {
+			bitfield_size = BTF_MEMBER_BITFIELD_SIZE(bit_offset);
+			bit_offset = BTF_MEMBER_BIT_OFFSET(bit_offset);
+		}
+
 		jsonw_name(d->jw, btf__name_by_offset(d->btf, m[i].name_off));
-		ret = btf_dumper_do_type(d, m[i].type,
-					 BITS_PER_BYTE_MASKED(m[i].offset),
-					 data_off);
-		if (ret)
-			break;
+		if (bitfield_size) {
+			btf_dumper_bitfield(bitfield_size, bit_offset,
+					    data, d->jw, d->is_plain_text);
+		} else {
+			data_off = data + BITS_ROUNDDOWN_BYTES(bit_offset);
+			ret = btf_dumper_do_type(d, m[i].type,
+						 BITS_PER_BYTE_MASKED(bit_offset),
+						 data_off);
+			if (ret)
+				break;
+		}
 	}
 
 	jsonw_end_object(d->jw);
@@ -295,6 +310,7 @@ static int __btf_dumper_type_only(const struct btf *btf, __u32 type_id,
 
 	switch (BTF_INFO_KIND(t->info)) {
 	case BTF_KIND_INT:
+	case BTF_KIND_TYPEDEF:
 		BTF_PRINT_ARG("%s ", btf__name_by_offset(btf, t->name_off));
 		break;
 	case BTF_KIND_STRUCT:
@@ -318,10 +334,11 @@ static int __btf_dumper_type_only(const struct btf *btf, __u32 type_id,
 		BTF_PRINT_TYPE(t->type);
 		BTF_PRINT_ARG("* ");
 		break;
-	case BTF_KIND_UNKN:
 	case BTF_KIND_FWD:
-	case BTF_KIND_TYPEDEF:
-		return -1;
+		BTF_PRINT_ARG("%s %s ",
+			      BTF_INFO_KFLAG(t->info) ? "union" : "struct",
+			      btf__name_by_offset(btf, t->name_off));
+		break;
 	case BTF_KIND_VOLATILE:
 		BTF_PRINT_ARG("volatile ");
 		BTF_PRINT_TYPE(t->type);
@@ -345,6 +362,7 @@ static int __btf_dumper_type_only(const struct btf *btf, __u32 type_id,
 		if (pos == -1)
 			return -1;
 		break;
+	case BTF_KIND_UNKN:
 	default:
 		return -1;
 	}
-- 
2.17.1
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