[PATCH bpf-next v2 1/5] bpf: compute bpf_skc_to_*() helper socket btf ids at build time

[PATCH bpf-next v2 1/5] bpf: compute bpf_skc_to_*() helper socket btf ids at build time

[Yonghong Song]

Currently, socket types (struct tcp_sock, udp_sock, etc.)
used by bpf_skc_to_*() helpers are computed when vmlinux_btf
is first built in the kernel.

Commit 5a2798ab32ba
("bpf: Add BTF_ID_LIST/BTF_ID/BTF_ID_UNUSED macros")
implemented a mechanism to compute btf_ids at kernel build
time which can simplify kernel implementation and reduce
runtime overhead by removing in-kernel btf_id calculation.
This patch did exactly this, removing in-kernel btf_id
computation and utilizing build-time btf_id computation.

If CONFIG_DEBUG_INFO_BTF is not defined, BTF_ID_LIST will
define an array with size of 5, which is not enough for
btf_sock_ids. So define its own static array if
CONFIG_DEBUG_INFO_BTF is not defined.

Signed-off-by: Yonghong Song <yhs@fb.com>
---
 include/linux/bpf.h |  4 ----
 kernel/bpf/btf.c    |  1 -
 net/core/filter.c   | 49 +++++++++++++++++----------------------------
 3 files changed, 18 insertions(+), 36 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index adb16bdc5f0a..1df1c0fd3f28 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1541,7 +1541,6 @@ static inline bool bpf_map_is_dev_bound(struct bpf_map *map)
 
 struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr);
 void bpf_map_offload_map_free(struct bpf_map *map);
-void init_btf_sock_ids(struct btf *btf);
 #else
 static inline int bpf_prog_offload_init(struct bpf_prog *prog,
 					union bpf_attr *attr)
@@ -1567,9 +1566,6 @@ static inline struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr)
 static inline void bpf_map_offload_map_free(struct bpf_map *map)
 {
 }
-static inline void init_btf_sock_ids(struct btf *btf)
-{
-}
 #endif /* CONFIG_NET && CONFIG_BPF_SYSCALL */
 
 #if defined(CONFIG_BPF_STREAM_PARSER)
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 03d6d43bb1d6..315cde73421b 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -3672,7 +3672,6 @@ struct btf *btf_parse_vmlinux(void)
 		goto errout;
 
 	bpf_struct_ops_init(btf, log);
-	init_btf_sock_ids(btf);
 
 	btf_verifier_env_free(env);
 	refcount_set(&btf->refcnt, 1);
diff --git a/net/core/filter.c b/net/core/filter.c
index 2bd129b5ae74..5a65fb4b95ff 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -9426,19 +9426,19 @@ void bpf_prog_change_xdp(struct bpf_prog *prev_prog, struct bpf_prog *prog)
  * sock_common as the first argument in its memory layout.
  */
 #define BTF_SOCK_TYPE_xxx \
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET, "inet_sock")			\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_CONN, "inet_connection_sock")	\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_REQ, "inet_request_sock")	\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_TW, "inet_timewait_sock")	\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_REQ, "request_sock")		\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_SOCK, "sock")			\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_SOCK_COMMON, "sock_common")		\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP, "tcp_sock")			\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_REQ, "tcp_request_sock")	\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_TW, "tcp_timewait_sock")	\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP6, "tcp6_sock")			\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP, "udp_sock")			\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP6, "udp6_sock")
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET, inet_sock)			\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_CONN, inet_connection_sock)	\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_REQ, inet_request_sock)	\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_TW, inet_timewait_sock)	\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_REQ, request_sock)			\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_SOCK, sock)				\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_SOCK_COMMON, sock_common)		\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP, tcp_sock)			\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_REQ, tcp_request_sock)		\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_TW, tcp_timewait_sock)		\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP6, tcp6_sock)			\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP, udp_sock)			\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP6, udp6_sock)
 
 enum {
 #define BTF_SOCK_TYPE(name, str) name,
@@ -9447,26 +9447,13 @@ BTF_SOCK_TYPE_xxx
 MAX_BTF_SOCK_TYPE,
 };
 
-static int btf_sock_ids[MAX_BTF_SOCK_TYPE];
-
-#ifdef CONFIG_BPF_SYSCALL
-static const char *bpf_sock_types[] = {
-#define BTF_SOCK_TYPE(name, str) str,
+#ifdef CONFIG_DEBUG_INFO_BTF
+BTF_ID_LIST(btf_sock_ids)
+#define BTF_SOCK_TYPE(name, type) BTF_ID(struct, type)
 BTF_SOCK_TYPE_xxx
 #undef BTF_SOCK_TYPE
-};
-
-void init_btf_sock_ids(struct btf *btf)
-{
-	int i, btf_id;
-
-	for (i = 0; i < MAX_BTF_SOCK_TYPE; i++) {
-		btf_id = btf_find_by_name_kind(btf, bpf_sock_types[i],
-					       BTF_KIND_STRUCT);
-		if (btf_id > 0)
-			btf_sock_ids[i] = btf_id;
-	}
-}
+#else
+static u32 btf_sock_ids[MAX_BTF_SOCK_TYPE];
 #endif
 
 static bool check_arg_btf_id(u32 btf_id, u32 arg)
-- 
2.24.1

[PATCH bpf-next v2 0/5] bpf: compute btf_ids at build time for btf_iter

[Yonghong Song]

Commit 5a2798ab32ba
("bpf: Add BTF_ID_LIST/BTF_ID/BTF_ID_UNUSED macros")
implemented a mechanism to compute btf_ids at kernel build
time which can simplify kernel implementation and reduce
runtime overhead by removing in-kernel btf_id calculation.

This patch set tried to use this mechanism to compute
btf_ids for bpf_skc_to_*() helpers and for btf_id_or_null ctx
arguments specified during bpf iterator registration.
Please see individual patch for details.

Changelogs:
  v1 -> v2:
    - v1 ([1]) is only for bpf_skc_to_*() helpers. This version
      expanded it to cover ctx btf_id_or_null arguments
    - abandoned the change of "extern u32 name[]" to
      "static u32 name[]" for BPF_ID_LIST local "name" definition.
      gcc 9 incurred a compilation error.

 [1]: https://lore.kernel.org/bpf/20200717184706.3476992-1-yhs@fb.com/T

Yonghong Song (5):
  bpf: compute bpf_skc_to_*() helper socket btf ids at build time
  tools/bpf: sync btf_ids.h to tools
  bpf: add BTF_ID_LIST_GLOBAL in btf_ids.h
  bpf: make btf_sock_ids global
  bpf: net: use precomputed btf_id for bpf iterators

 include/linux/bpf.h                           |  5 +-
 include/linux/btf_ids.h                       | 40 +++++++++++++--
 kernel/bpf/btf.c                              |  6 +--
 kernel/bpf/map_iter.c                         |  7 ++-
 kernel/bpf/task_iter.c                        | 12 ++++-
 net/core/filter.c                             | 49 ++----------------
 net/ipv4/tcp_ipv4.c                           |  4 +-
 net/ipv4/udp.c                                |  4 +-
 net/ipv6/route.c                              |  7 ++-
 net/netlink/af_netlink.c                      |  7 ++-
 tools/include/linux/btf_ids.h                 | 51 +++++++++++++++++--
 .../selftests/bpf/prog_tests/resolve_btfids.c | 34 ++++++++++---
 12 files changed, 153 insertions(+), 73 deletions(-)

-- 
2.24.1

[PATCH bpf-next v2 2/5] tools/bpf: sync btf_ids.h to tools

[Yonghong Song]

Sync kernel header btf_ids.h to tools directory.
Also define macro CONFIG_DEBUG_INFO_BTF before
including btf_ids.h in prog_tests/resolve_btfids.c
since non-stub definitions for BTF_ID_LIST etc. macros
are defined under CONFIG_DEBUG_INFO_BTF. This
prevented test_progs from failing.

Signed-off-by: Yonghong Song <yhs@fb.com>
---
 tools/include/linux/btf_ids.h                         | 11 ++++++++++-
 .../testing/selftests/bpf/prog_tests/resolve_btfids.c |  1 +
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/tools/include/linux/btf_ids.h b/tools/include/linux/btf_ids.h
index fe019774f8a7..1cdb56950ffe 100644
--- a/tools/include/linux/btf_ids.h
+++ b/tools/include/linux/btf_ids.h
@@ -3,6 +3,8 @@
 #ifndef _LINUX_BTF_IDS_H
 #define _LINUX_BTF_IDS_H
 
+#ifdef CONFIG_DEBUG_INFO_BTF
+
 #include <linux/compiler.h> /* for __PASTE */
 
 /*
@@ -21,7 +23,7 @@
 asm(							\
 ".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
 ".local " #symbol " ;                          \n"	\
-".type  " #symbol ", @object;                  \n"	\
+".type  " #symbol ", STT_OBJECT;               \n"	\
 ".size  " #symbol ", 4;                        \n"	\
 #symbol ":                                     \n"	\
 ".zero 4                                       \n"	\
@@ -83,5 +85,12 @@ asm(							\
 ".zero 4                                       \n"	\
 ".popsection;                                  \n");
 
+#else
+
+#define BTF_ID_LIST(name) static u32 name[5];
+#define BTF_ID(prefix, name)
+#define BTF_ID_UNUSED
+
+#endif /* CONFIG_DEBUG_INFO_BTF */
 
 #endif
diff --git a/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c b/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c
index 403be6f36cba..22d83bba4e91 100644
--- a/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c
+++ b/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c
@@ -6,6 +6,7 @@
 #include <bpf/libbpf.h>
 #include <linux/btf.h>
 #include <linux/kernel.h>
+#define CONFIG_DEBUG_INFO_BTF
 #include <linux/btf_ids.h>
 #include "test_progs.h"
 
-- 
2.24.1

[PATCH bpf-next v2 3/5] bpf: add BTF_ID_LIST_GLOBAL in btf_ids.h

[Yonghong Song]

Existing BTF_ID_LIST used a local static variable
to store btf_ids. This patch provided a new macro
BTF_ID_LIST_GLOBAL to store btf_ids in a global
variable which can be shared among multiple files.

The existing BTF_ID_LIST is still retained.
Two reasons. First, BTF_ID_LIST is also used to build
btf_ids for helper arguments which typically
is an array of 5. Since typically different
helpers have different signature, it makes
little sense to share them. Second, some
current computed btf_ids are indeed local.
If later those btf_ids are shared between
different files, they can use BTF_ID_LIST_GLOBAL then.

Signed-off-by: Yonghong Song <yhs@fb.com>
---
 include/linux/btf_ids.h                       | 10 ++++--
 tools/include/linux/btf_ids.h                 | 10 ++++--
 .../selftests/bpf/prog_tests/resolve_btfids.c | 33 ++++++++++++++-----
 3 files changed, 39 insertions(+), 14 deletions(-)

diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 1cdb56950ffe..77ab45baa095 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -57,17 +57,20 @@ asm(							\
  * .zero 4
  *
  */
-#define __BTF_ID_LIST(name)				\
+#define __BTF_ID_LIST(name, scope)			\
 asm(							\
 ".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
-".local " #name ";                             \n"	\
+"." #scope " " #name ";                        \n"	\
 #name ":;                                      \n"	\
 ".popsection;                                  \n");	\
 
 #define BTF_ID_LIST(name)				\
-__BTF_ID_LIST(name)					\
+__BTF_ID_LIST(name, local)				\
 extern u32 name[];
 
+#define BTF_ID_LIST_GLOBAL(name)			\
+__BTF_ID_LIST(name, globl)
+
 /*
  * The BTF_ID_UNUSED macro defines 4 zero bytes.
  * It's used when we want to define 'unused' entry
@@ -90,6 +93,7 @@ asm(							\
 #define BTF_ID_LIST(name) static u32 name[5];
 #define BTF_ID(prefix, name)
 #define BTF_ID_UNUSED
+#define BTF_ID_LIST_GLOBAL(name) u32 name[1];
 
 #endif /* CONFIG_DEBUG_INFO_BTF */
 
diff --git a/tools/include/linux/btf_ids.h b/tools/include/linux/btf_ids.h
index 1cdb56950ffe..77ab45baa095 100644
--- a/tools/include/linux/btf_ids.h
+++ b/tools/include/linux/btf_ids.h
@@ -57,17 +57,20 @@ asm(							\
  * .zero 4
  *
  */
-#define __BTF_ID_LIST(name)				\
+#define __BTF_ID_LIST(name, scope)			\
 asm(							\
 ".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
-".local " #name ";                             \n"	\
+"." #scope " " #name ";                        \n"	\
 #name ":;                                      \n"	\
 ".popsection;                                  \n");	\
 
 #define BTF_ID_LIST(name)				\
-__BTF_ID_LIST(name)					\
+__BTF_ID_LIST(name, local)				\
 extern u32 name[];
 
+#define BTF_ID_LIST_GLOBAL(name)			\
+__BTF_ID_LIST(name, globl)
+
 /*
  * The BTF_ID_UNUSED macro defines 4 zero bytes.
  * It's used when we want to define 'unused' entry
@@ -90,6 +93,7 @@ asm(							\
 #define BTF_ID_LIST(name) static u32 name[5];
 #define BTF_ID(prefix, name)
 #define BTF_ID_UNUSED
+#define BTF_ID_LIST_GLOBAL(name) u32 name[1];
 
 #endif /* CONFIG_DEBUG_INFO_BTF */
 
diff --git a/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c b/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c
index 22d83bba4e91..3b127cab4864 100644
--- a/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c
+++ b/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c
@@ -28,7 +28,17 @@ struct symbol test_symbols[] = {
 	{ "func",    BTF_KIND_FUNC,    -1 },
 };
 
-BTF_ID_LIST(test_list)
+BTF_ID_LIST(test_list_local)
+BTF_ID_UNUSED
+BTF_ID(typedef, S)
+BTF_ID(typedef, T)
+BTF_ID(typedef, U)
+BTF_ID(struct,  S)
+BTF_ID(union,   U)
+BTF_ID(func,    func)
+
+extern __u32 test_list_global[];
+BTF_ID_LIST_GLOBAL(test_list_global)
 BTF_ID_UNUSED
 BTF_ID(typedef, S)
 BTF_ID(typedef, T)
@@ -94,18 +104,25 @@ static int resolve_symbols(void)
 
 int test_resolve_btfids(void)
 {
-	unsigned int i;
+	__u32 *test_list, *test_lists[] = { test_list_local, test_list_global };
+	unsigned int i, j;
 	int ret = 0;
 
 	if (resolve_symbols())
 		return -1;
 
-	/* Check BTF_ID_LIST(test_list) IDs */
-	for (i = 0; i < ARRAY_SIZE(test_symbols) && !ret; i++) {
-		ret = CHECK(test_list[i] != test_symbols[i].id,
-			    "id_check",
-			    "wrong ID for %s (%d != %d)\n", test_symbols[i].name,
-			    test_list[i], test_symbols[i].id);
+	/* Check BTF_ID_LIST(test_list_local) and
+	 * BTF_ID_LIST_GLOBAL(test_list_global) IDs
+	 */
+	for (j = 0; j < ARRAY_SIZE(test_lists); j++) {
+		test_list = test_lists[j];
+		for (i = 0; i < ARRAY_SIZE(test_symbols) && !ret; i++) {
+			ret = CHECK(test_list[i] != test_symbols[i].id,
+				    "id_check",
+				    "wrong ID for %s (%d != %d)\n",
+				    test_symbols[i].name,
+				    test_list[i], test_symbols[i].id);
+		}
 	}
 
 	return ret;
-- 
2.24.1

[PATCH bpf-next v2 4/5] bpf: make btf_sock_ids global

[Yonghong Song]

tcp and udp bpf_iter can reuse some socket ids in
btf_sock_ids, so make it global.

I put the extern definition in btf_ids.h as a central
place so it can be easily discovered by developers.

Signed-off-by: Yonghong Song <yhs@fb.com>
---
 include/linux/btf_ids.h       | 30 ++++++++++++++++++++++++++++++
 net/core/filter.c             | 30 ++----------------------------
 tools/include/linux/btf_ids.h | 30 ++++++++++++++++++++++++++++++
 3 files changed, 62 insertions(+), 28 deletions(-)

diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 77ab45baa095..4867d549e3c1 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -97,4 +97,34 @@ asm(							\
 
 #endif /* CONFIG_DEBUG_INFO_BTF */
 
+#ifdef CONFIG_NET
+/* Define a list of socket types which can be the argument for
+ * skc_to_*_sock() helpers. All these sockets should have
+ * sock_common as the first argument in its memory layout.
+ */
+#define BTF_SOCK_TYPE_xxx \
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET, inet_sock)			\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_CONN, inet_connection_sock)	\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_REQ, inet_request_sock)	\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_TW, inet_timewait_sock)	\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_REQ, request_sock)			\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_SOCK, sock)				\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_SOCK_COMMON, sock_common)		\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP, tcp_sock)			\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_REQ, tcp_request_sock)		\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_TW, tcp_timewait_sock)		\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP6, tcp6_sock)			\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP, udp_sock)			\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP6, udp6_sock)
+
+enum {
+#define BTF_SOCK_TYPE(name, str) name,
+BTF_SOCK_TYPE_xxx
+#undef BTF_SOCK_TYPE
+MAX_BTF_SOCK_TYPE,
+};
+
+extern u32 btf_sock_ids[];
+#endif
+
 #endif
diff --git a/net/core/filter.c b/net/core/filter.c
index 5a65fb4b95ff..654c346b7d91 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -9421,39 +9421,13 @@ void bpf_prog_change_xdp(struct bpf_prog *prev_prog, struct bpf_prog *prog)
 	bpf_dispatcher_change_prog(BPF_DISPATCHER_PTR(xdp), prev_prog, prog);
 }
 
-/* Define a list of socket types which can be the argument for
- * skc_to_*_sock() helpers. All these sockets should have
- * sock_common as the first argument in its memory layout.
- */
-#define BTF_SOCK_TYPE_xxx \
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET, inet_sock)			\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_CONN, inet_connection_sock)	\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_REQ, inet_request_sock)	\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_TW, inet_timewait_sock)	\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_REQ, request_sock)			\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_SOCK, sock)				\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_SOCK_COMMON, sock_common)		\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP, tcp_sock)			\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_REQ, tcp_request_sock)		\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_TW, tcp_timewait_sock)		\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP6, tcp6_sock)			\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP, udp_sock)			\
-	BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP6, udp6_sock)
-
-enum {
-#define BTF_SOCK_TYPE(name, str) name,
-BTF_SOCK_TYPE_xxx
-#undef BTF_SOCK_TYPE
-MAX_BTF_SOCK_TYPE,
-};
-
 #ifdef CONFIG_DEBUG_INFO_BTF
-BTF_ID_LIST(btf_sock_ids)
+BTF_ID_LIST_GLOBAL(btf_sock_ids)
 #define BTF_SOCK_TYPE(name, type) BTF_ID(struct, type)
 BTF_SOCK_TYPE_xxx
 #undef BTF_SOCK_TYPE
 #else
-static u32 btf_sock_ids[MAX_BTF_SOCK_TYPE];
+u32 btf_sock_ids[MAX_BTF_SOCK_TYPE];
 #endif
 
 static bool check_arg_btf_id(u32 btf_id, u32 arg)
diff --git a/tools/include/linux/btf_ids.h b/tools/include/linux/btf_ids.h
index 77ab45baa095..4867d549e3c1 100644
--- a/tools/include/linux/btf_ids.h
+++ b/tools/include/linux/btf_ids.h
@@ -97,4 +97,34 @@ asm(							\
 
 #endif /* CONFIG_DEBUG_INFO_BTF */
 
+#ifdef CONFIG_NET
+/* Define a list of socket types which can be the argument for
+ * skc_to_*_sock() helpers. All these sockets should have
+ * sock_common as the first argument in its memory layout.
+ */
+#define BTF_SOCK_TYPE_xxx \
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET, inet_sock)			\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_CONN, inet_connection_sock)	\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_REQ, inet_request_sock)	\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_TW, inet_timewait_sock)	\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_REQ, request_sock)			\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_SOCK, sock)				\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_SOCK_COMMON, sock_common)		\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP, tcp_sock)			\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_REQ, tcp_request_sock)		\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_TW, tcp_timewait_sock)		\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP6, tcp6_sock)			\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP, udp_sock)			\
+	BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP6, udp6_sock)
+
+enum {
+#define BTF_SOCK_TYPE(name, str) name,
+BTF_SOCK_TYPE_xxx
+#undef BTF_SOCK_TYPE
+MAX_BTF_SOCK_TYPE,
+};
+
+extern u32 btf_sock_ids[];
+#endif
+
 #endif
-- 
2.24.1

[PATCH bpf-next v2 5/5] bpf: net: use precomputed btf_id for bpf iterators

[Yonghong Song]

One additional field btf_id is added to struct
bpf_ctx_arg_aux to store the precomputed btf_ids.
The btf_id is computed at build time with
BTF_ID_LIST or BTF_ID_LIST_GLOBAL macro definitions.
All existing bpf iterators are changed to used
pre-compute btf_ids.

Signed-off-by: Yonghong Song <yhs@fb.com>
---
 include/linux/bpf.h      |  1 +
 kernel/bpf/btf.c         |  5 +++--
 kernel/bpf/map_iter.c    |  7 ++++++-
 kernel/bpf/task_iter.c   | 12 ++++++++++--
 net/ipv4/tcp_ipv4.c      |  4 +++-
 net/ipv4/udp.c           |  4 +++-
 net/ipv6/route.c         |  7 ++++++-
 net/netlink/af_netlink.c |  7 ++++++-
 8 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 1df1c0fd3f28..bae557ff2da8 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -668,6 +668,7 @@ struct bpf_jit_poke_descriptor {
 struct bpf_ctx_arg_aux {
 	u32 offset;
 	enum bpf_reg_type reg_type;
+	u32 btf_id;
 };
 
 struct bpf_prog_aux {
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 315cde73421b..ee36b7f60936 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -3817,16 +3817,17 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
 		return true;
 
 	/* this is a pointer to another type */
-	info->reg_type = PTR_TO_BTF_ID;
 	for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
 		const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
 
 		if (ctx_arg_info->offset == off) {
 			info->reg_type = ctx_arg_info->reg_type;
-			break;
+			info->btf_id = ctx_arg_info->btf_id;
+			return true;
 		}
 	}
 
+	info->reg_type = PTR_TO_BTF_ID;
 	if (tgt_prog) {
 		ret = btf_translate_to_vmlinux(log, btf, t, tgt_prog->type, arg);
 		if (ret > 0) {
diff --git a/kernel/bpf/map_iter.c b/kernel/bpf/map_iter.c
index c69071e334bf..8a7af11b411f 100644
--- a/kernel/bpf/map_iter.c
+++ b/kernel/bpf/map_iter.c
@@ -4,6 +4,7 @@
 #include <linux/fs.h>
 #include <linux/filter.h>
 #include <linux/kernel.h>
+#include <linux/btf_ids.h>
 
 struct bpf_iter_seq_map_info {
 	u32 mid;
@@ -81,7 +82,10 @@ static const struct seq_operations bpf_map_seq_ops = {
 	.show	= bpf_map_seq_show,
 };
 
-static const struct bpf_iter_reg bpf_map_reg_info = {
+BTF_ID_LIST(btf_bpf_map_id)
+BTF_ID(struct, bpf_map)
+
+static struct bpf_iter_reg bpf_map_reg_info = {
 	.target			= "bpf_map",
 	.seq_ops		= &bpf_map_seq_ops,
 	.init_seq_private	= NULL,
@@ -96,6 +100,7 @@ static const struct bpf_iter_reg bpf_map_reg_info = {
 
 static int __init bpf_map_iter_init(void)
 {
+	bpf_map_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_map_id;
 	return bpf_iter_reg_target(&bpf_map_reg_info);
 }
 
diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
index 4dbf2b6035f8..2feecf095609 100644
--- a/kernel/bpf/task_iter.c
+++ b/kernel/bpf/task_iter.c
@@ -7,6 +7,7 @@
 #include <linux/fs.h>
 #include <linux/fdtable.h>
 #include <linux/filter.h>
+#include <linux/btf_ids.h>
 
 struct bpf_iter_seq_task_common {
 	struct pid_namespace *ns;
@@ -312,7 +313,11 @@ static const struct seq_operations task_file_seq_ops = {
 	.show	= task_file_seq_show,
 };
 
-static const struct bpf_iter_reg task_reg_info = {
+BTF_ID_LIST(btf_task_file_ids)
+BTF_ID(struct, task_struct)
+BTF_ID(struct, file)
+
+static struct bpf_iter_reg task_reg_info = {
 	.target			= "task",
 	.seq_ops		= &task_seq_ops,
 	.init_seq_private	= init_seq_pidns,
@@ -325,7 +330,7 @@ static const struct bpf_iter_reg task_reg_info = {
 	},
 };
 
-static const struct bpf_iter_reg task_file_reg_info = {
+static struct bpf_iter_reg task_file_reg_info = {
 	.target			= "task_file",
 	.seq_ops		= &task_file_seq_ops,
 	.init_seq_private	= init_seq_pidns,
@@ -344,10 +349,13 @@ static int __init task_iter_init(void)
 {
 	int ret;
 
+	task_reg_info.ctx_arg_info[0].btf_id = btf_task_file_ids[0];
 	ret = bpf_iter_reg_target(&task_reg_info);
 	if (ret)
 		return ret;
 
+	task_file_reg_info.ctx_arg_info[0].btf_id = btf_task_file_ids[0];
+	task_file_reg_info.ctx_arg_info[1].btf_id = btf_task_file_ids[1];
 	return bpf_iter_reg_target(&task_file_reg_info);
 }
 late_initcall(task_iter_init);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 116c11a0aaed..a7f1b41482f8 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -76,6 +76,7 @@
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/inetdevice.h>
+#include <linux/btf_ids.h>
 
 #include <crypto/hash.h>
 #include <linux/scatterlist.h>
@@ -2954,7 +2955,7 @@ static void bpf_iter_fini_tcp(void *priv_data)
 	bpf_iter_fini_seq_net(priv_data);
 }
 
-static const struct bpf_iter_reg tcp_reg_info = {
+static struct bpf_iter_reg tcp_reg_info = {
 	.target			= "tcp",
 	.seq_ops		= &bpf_iter_tcp_seq_ops,
 	.init_seq_private	= bpf_iter_init_tcp,
@@ -2969,6 +2970,7 @@ static const struct bpf_iter_reg tcp_reg_info = {
 
 static void __init bpf_iter_register(void)
 {
+	tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
 	if (bpf_iter_reg_target(&tcp_reg_info))
 		pr_warn("Warning: could not register bpf iterator tcp\n");
 }
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index b738c63d7a77..b5231ab350e0 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -106,6 +106,7 @@
 #include <net/xfrm.h>
 #include <trace/events/udp.h>
 #include <linux/static_key.h>
+#include <linux/btf_ids.h>
 #include <trace/events/skb.h>
 #include <net/busy_poll.h>
 #include "udp_impl.h"
@@ -3232,7 +3233,7 @@ static void bpf_iter_fini_udp(void *priv_data)
 	bpf_iter_fini_seq_net(priv_data);
 }
 
-static const struct bpf_iter_reg udp_reg_info = {
+static struct bpf_iter_reg udp_reg_info = {
 	.target			= "udp",
 	.seq_ops		= &bpf_iter_udp_seq_ops,
 	.init_seq_private	= bpf_iter_init_udp,
@@ -3247,6 +3248,7 @@ static const struct bpf_iter_reg udp_reg_info = {
 
 static void __init bpf_iter_register(void)
 {
+	udp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_UDP];
 	if (bpf_iter_reg_target(&udp_reg_info))
 		pr_warn("Warning: could not register bpf iterator udp\n");
 }
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 427b81cbc164..33f5efbad0a9 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -61,6 +61,7 @@
 #include <net/l3mdev.h>
 #include <net/ip.h>
 #include <linux/uaccess.h>
+#include <linux/btf_ids.h>
 
 #ifdef CONFIG_SYSCTL
 #include <linux/sysctl.h>
@@ -6423,7 +6424,10 @@ void __init ip6_route_init_special_entries(void)
 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
 DEFINE_BPF_ITER_FUNC(ipv6_route, struct bpf_iter_meta *meta, struct fib6_info *rt)
 
-static const struct bpf_iter_reg ipv6_route_reg_info = {
+BTF_ID_LIST(btf_fib6_info_id)
+BTF_ID(struct, fib6_info)
+
+static struct bpf_iter_reg ipv6_route_reg_info = {
 	.target			= "ipv6_route",
 	.seq_ops		= &ipv6_route_seq_ops,
 	.init_seq_private	= bpf_iter_init_seq_net,
@@ -6438,6 +6442,7 @@ static const struct bpf_iter_reg ipv6_route_reg_info = {
 
 static int __init bpf_iter_register(void)
 {
+	ipv6_route_reg_info.ctx_arg_info[0].btf_id = *btf_fib6_info_id;
 	return bpf_iter_reg_target(&ipv6_route_reg_info);
 }
 
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 4f2c3b14ddbf..3cd58f0c2de4 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -60,6 +60,7 @@
 #include <linux/genetlink.h>
 #include <linux/net_namespace.h>
 #include <linux/nospec.h>
+#include <linux/btf_ids.h>
 
 #include <net/net_namespace.h>
 #include <net/netns/generic.h>
@@ -2803,7 +2804,10 @@ static const struct rhashtable_params netlink_rhashtable_params = {
 };
 
 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
-static const struct bpf_iter_reg netlink_reg_info = {
+BTF_ID_LIST(btf_netlink_sock_id)
+BTF_ID(struct, netlink_sock)
+
+static struct bpf_iter_reg netlink_reg_info = {
 	.target			= "netlink",
 	.seq_ops		= &netlink_seq_ops,
 	.init_seq_private	= bpf_iter_init_seq_net,
@@ -2818,6 +2822,7 @@ static const struct bpf_iter_reg netlink_reg_info = {
 
 static int __init bpf_iter_register(void)
 {
+	netlink_reg_info.ctx_arg_info[0].btf_id = *btf_netlink_sock_id;
 	return bpf_iter_reg_target(&netlink_reg_info);
 }
 #endif
-- 
2.24.1

Re: [PATCH bpf-next v2 2/5] tools/bpf: sync btf_ids.h to tools

[Jiri Olsa]

On Mon, Jul 20, 2020 at 09:33:59AM -0700, Yonghong Song wrote:
> Sync kernel header btf_ids.h to tools directory.
> Also define macro CONFIG_DEBUG_INFO_BTF before
> including btf_ids.h in prog_tests/resolve_btfids.c
> since non-stub definitions for BTF_ID_LIST etc. macros
> are defined under CONFIG_DEBUG_INFO_BTF. This
> prevented test_progs from failing.

I was going to send this with the d_path change ;-)

thanks,
jirka

> 
> Signed-off-by: Yonghong Song <yhs@fb.com>
> ---
>  tools/include/linux/btf_ids.h                         | 11 ++++++++++-
>  .../testing/selftests/bpf/prog_tests/resolve_btfids.c |  1 +
>  2 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/include/linux/btf_ids.h b/tools/include/linux/btf_ids.h
> index fe019774f8a7..1cdb56950ffe 100644
> --- a/tools/include/linux/btf_ids.h
> +++ b/tools/include/linux/btf_ids.h
> @@ -3,6 +3,8 @@
>  #ifndef _LINUX_BTF_IDS_H
>  #define _LINUX_BTF_IDS_H
>  
> +#ifdef CONFIG_DEBUG_INFO_BTF
> +
>  #include <linux/compiler.h> /* for __PASTE */
>  
>  /*
> @@ -21,7 +23,7 @@
>  asm(							\
>  ".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
>  ".local " #symbol " ;                          \n"	\
> -".type  " #symbol ", @object;                  \n"	\
> +".type  " #symbol ", STT_OBJECT;               \n"	\
>  ".size  " #symbol ", 4;                        \n"	\
>  #symbol ":                                     \n"	\
>  ".zero 4                                       \n"	\
> @@ -83,5 +85,12 @@ asm(							\
>  ".zero 4                                       \n"	\
>  ".popsection;                                  \n");
>  
> +#else
> +
> +#define BTF_ID_LIST(name) static u32 name[5];
> +#define BTF_ID(prefix, name)
> +#define BTF_ID_UNUSED
> +
> +#endif /* CONFIG_DEBUG_INFO_BTF */
>  
>  #endif
> diff --git a/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c b/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c
> index 403be6f36cba..22d83bba4e91 100644
> --- a/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c
> +++ b/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c
> @@ -6,6 +6,7 @@
>  #include <bpf/libbpf.h>
>  #include <linux/btf.h>
>  #include <linux/kernel.h>
> +#define CONFIG_DEBUG_INFO_BTF
>  #include <linux/btf_ids.h>
>  #include "test_progs.h"
>  
> -- 
> 2.24.1
> 

Re: [PATCH bpf-next v2 3/5] bpf: add BTF_ID_LIST_GLOBAL in btf_ids.h

[Jiri Olsa]

On Mon, Jul 20, 2020 at 09:34:01AM -0700, Yonghong Song wrote:
> Existing BTF_ID_LIST used a local static variable
> to store btf_ids. This patch provided a new macro
> BTF_ID_LIST_GLOBAL to store btf_ids in a global
> variable which can be shared among multiple files.
> 
> The existing BTF_ID_LIST is still retained.
> Two reasons. First, BTF_ID_LIST is also used to build
> btf_ids for helper arguments which typically
> is an array of 5. Since typically different
> helpers have different signature, it makes
> little sense to share them. Second, some
> current computed btf_ids are indeed local.
> If later those btf_ids are shared between
> different files, they can use BTF_ID_LIST_GLOBAL then.
> 
> Signed-off-by: Yonghong Song <yhs@fb.com>

Acked-by: Jiri Olsa <jolsa@redhat.com>

jirka

Re: [PATCH bpf-next v2 0/5] bpf: compute btf_ids at build time for btf_iter

[Alexei Starovoitov]

On Mon, Jul 20, 2020 at 09:33:58AM -0700, Yonghong Song wrote:
> Commit 5a2798ab32ba
> ("bpf: Add BTF_ID_LIST/BTF_ID/BTF_ID_UNUSED macros")
> implemented a mechanism to compute btf_ids at kernel build
> time which can simplify kernel implementation and reduce
> runtime overhead by removing in-kernel btf_id calculation.
> 
> This patch set tried to use this mechanism to compute
> btf_ids for bpf_skc_to_*() helpers and for btf_id_or_null ctx
> arguments specified during bpf iterator registration.
> Please see individual patch for details.
> 
> Changelogs:
>   v1 -> v2:
>     - v1 ([1]) is only for bpf_skc_to_*() helpers. This version
>       expanded it to cover ctx btf_id_or_null arguments
>     - abandoned the change of "extern u32 name[]" to
>       "static u32 name[]" for BPF_ID_LIST local "name" definition.
>       gcc 9 incurred a compilation error.
> 
>  [1]: https://lore.kernel.org/bpf/20200717184706.3476992-1-yhs@fb.com/T

Applied, Thanks