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Message-ID: <20200720163401.1393159-1-yhs@fb.com>
Date: Mon, 20 Jul 2020 09:34:01 -0700
From: Yonghong Song <yhs@...com>
To: <bpf@...r.kernel.org>, <netdev@...r.kernel.org>
CC: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Jiri Olsa <jolsa@...nel.org>, <kernel-team@...com>
Subject: [PATCH bpf-next v2 3/5] bpf: add BTF_ID_LIST_GLOBAL in btf_ids.h
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@...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
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