From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Move the BTF APIs used in tracing to the BTF library code for sharing it
with others.
Previously, to avoid complex dependency in a series I made it on the
tracing tree, but now it is a good time to move it to BPF tree because
these functions are pure BTF functions.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
---
include/linux/btf.h | 24 +++++++++
kernel/bpf/btf.c | 115 +++++++++++++++++++++++++++++++++++++++++
kernel/trace/Makefile | 1
kernel/trace/trace_btf.c | 122 --------------------------------------------
kernel/trace/trace_btf.h | 11 ----
kernel/trace/trace_probe.c | 2 -
6 files changed, 140 insertions(+), 135 deletions(-)
delete mode 100644 kernel/trace/trace_btf.c
delete mode 100644 kernel/trace/trace_btf.h
diff --git a/include/linux/btf.h b/include/linux/btf.h
index 928113a80a95..8372d93ea402 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -507,6 +507,14 @@ btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type prog_type);
bool btf_types_are_same(const struct btf *btf1, u32 id1,
const struct btf *btf2, u32 id2);
+const struct btf_type *btf_find_func_proto(const char *func_name,
+ struct btf **btf_p);
+const struct btf_param *btf_get_func_param(const struct btf_type *func_proto,
+ s32 *nr);
+const struct btf_member *btf_find_struct_member(struct btf *btf,
+ const struct btf_type *type,
+ const char *member_name,
+ u32 *anon_offset);
#else
static inline const struct btf_type *btf_type_by_id(const struct btf *btf,
u32 type_id)
@@ -559,6 +567,22 @@ static inline bool btf_types_are_same(const struct btf *btf1, u32 id1,
{
return false;
}
+static inline const struct btf_type *btf_find_func_proto(const char *func_name,
+ struct btf **btf_p)
+{
+ return NULL;
+}
+static inline const struct btf_param *
+btf_get_func_param(const struct btf_type *func_proto, s32 *nr)
+{
+ return NULL;
+}
+static inline const struct btf_member *
+btf_find_struct_member(struct btf *btf, const struct btf_type *type,
+ const char *member_name, u32 *anon_offset)
+{
+ return NULL;
+}
#endif
static inline bool btf_type_is_struct_ptr(struct btf *btf, const struct btf_type *t)
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 8090d7fb11ef..e5cbf3b31b78 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -912,6 +912,121 @@ static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf,
return t;
}
+/*
+ * Find a function proto type by name, and return the btf_type with its btf
+ * in *@btf_p. Return NULL if not found.
+ * Note that caller has to call btf_put(*@btf_p) after using the btf_type.
+ */
+const struct btf_type *btf_find_func_proto(const char *func_name, struct btf **btf_p)
+{
+ const struct btf_type *t;
+ s32 id;
+
+ id = bpf_find_btf_id(func_name, BTF_KIND_FUNC, btf_p);
+ if (id < 0)
+ return NULL;
+
+ /* Get BTF_KIND_FUNC type */
+ t = btf_type_by_id(*btf_p, id);
+ if (!t || !btf_type_is_func(t))
+ goto err;
+
+ /* The type of BTF_KIND_FUNC is BTF_KIND_FUNC_PROTO */
+ t = btf_type_by_id(*btf_p, t->type);
+ if (!t || !btf_type_is_func_proto(t))
+ goto err;
+
+ return t;
+err:
+ btf_put(*btf_p);
+ return NULL;
+}
+
+/*
+ * Get function parameter with the number of parameters.
+ * This can return NULL if the function has no parameters.
+ * It can return -EINVAL if the @func_proto is not a function proto type.
+ */
+const struct btf_param *btf_get_func_param(const struct btf_type *func_proto, s32 *nr)
+{
+ if (!btf_type_is_func_proto(func_proto))
+ return ERR_PTR(-EINVAL);
+
+ *nr = btf_type_vlen(func_proto);
+ if (*nr > 0)
+ return (const struct btf_param *)(func_proto + 1);
+ else
+ return NULL;
+}
+
+#define BTF_ANON_STACK_MAX 16
+
+struct btf_anon_stack {
+ u32 tid;
+ u32 offset;
+};
+
+/*
+ * Find a member of data structure/union by name and return it.
+ * Return NULL if not found, or -EINVAL if parameter is invalid.
+ * If the member is an member of anonymous union/structure, the offset
+ * of that anonymous union/structure is stored into @anon_offset. Caller
+ * can calculate the correct offset from the root data structure by
+ * adding anon_offset to the member's offset.
+ */
+const struct btf_member *btf_find_struct_member(struct btf *btf,
+ const struct btf_type *type,
+ const char *member_name,
+ u32 *anon_offset)
+{
+ struct btf_anon_stack *anon_stack;
+ const struct btf_member *member;
+ u32 tid, cur_offset = 0;
+ const char *name;
+ int i, top = 0;
+
+ anon_stack = kcalloc(BTF_ANON_STACK_MAX, sizeof(*anon_stack), GFP_KERNEL);
+ if (!anon_stack)
+ return ERR_PTR(-ENOMEM);
+
+retry:
+ if (!btf_type_is_struct(type)) {
+ member = ERR_PTR(-EINVAL);
+ goto out;
+ }
+
+ for_each_member(i, type, member) {
+ if (!member->name_off) {
+ /* Anonymous union/struct: push it for later use */
+ type = btf_type_skip_modifiers(btf, member->type, &tid);
+ if (type && top < BTF_ANON_STACK_MAX) {
+ anon_stack[top].tid = tid;
+ anon_stack[top++].offset =
+ cur_offset + member->offset;
+ }
+ } else {
+ name = btf_name_by_offset(btf, member->name_off);
+ if (name && !strcmp(member_name, name)) {
+ if (anon_offset)
+ *anon_offset = cur_offset;
+ goto out;
+ }
+ }
+ }
+ if (top > 0) {
+ /* Pop from the anonymous stack and retry */
+ tid = anon_stack[--top].tid;
+ cur_offset = anon_stack[top].offset;
+ type = btf_type_by_id(btf, tid);
+ goto retry;
+ }
+ member = NULL;
+
+out:
+ kfree(anon_stack);
+ return member;
+}
+
#define BTF_SHOW_MAX_ITER 10
#define BTF_KIND_BIT(kind) (1ULL << kind)
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 057cd975d014..64b61f67a403 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -99,7 +99,6 @@ obj-$(CONFIG_KGDB_KDB) += trace_kdb.o
endif
obj-$(CONFIG_DYNAMIC_EVENTS) += trace_dynevent.o
obj-$(CONFIG_PROBE_EVENTS) += trace_probe.o
-obj-$(CONFIG_PROBE_EVENTS_BTF_ARGS) += trace_btf.o
obj-$(CONFIG_UPROBE_EVENTS) += trace_uprobe.o
obj-$(CONFIG_BOOTTIME_TRACING) += trace_boot.o
obj-$(CONFIG_FTRACE_RECORD_RECURSION) += trace_recursion_record.o
diff --git a/kernel/trace/trace_btf.c b/kernel/trace/trace_btf.c
deleted file mode 100644
index ca224d53bfdc..000000000000
--- a/kernel/trace/trace_btf.c
+++ /dev/null
@@ -1,122 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#include <linux/btf.h>
-#include <linux/kernel.h>
-#include <linux/slab.h>
-
-#include "trace_btf.h"
-
-/*
- * Find a function proto type by name, and return the btf_type with its btf
- * in *@btf_p. Return NULL if not found.
- * Note that caller has to call btf_put(*@btf_p) after using the btf_type.
- */
-const struct btf_type *btf_find_func_proto(const char *func_name, struct btf **btf_p)
-{
- const struct btf_type *t;
- s32 id;
-
- id = bpf_find_btf_id(func_name, BTF_KIND_FUNC, btf_p);
- if (id < 0)
- return NULL;
-
- /* Get BTF_KIND_FUNC type */
- t = btf_type_by_id(*btf_p, id);
- if (!t || !btf_type_is_func(t))
- goto err;
-
- /* The type of BTF_KIND_FUNC is BTF_KIND_FUNC_PROTO */
- t = btf_type_by_id(*btf_p, t->type);
- if (!t || !btf_type_is_func_proto(t))
- goto err;
-
- return t;
-err:
- btf_put(*btf_p);
- return NULL;
-}
-
-/*
- * Get function parameter with the number of parameters.
- * This can return NULL if the function has no parameters.
- * It can return -EINVAL if the @func_proto is not a function proto type.
- */
-const struct btf_param *btf_get_func_param(const struct btf_type *func_proto, s32 *nr)
-{
- if (!btf_type_is_func_proto(func_proto))
- return ERR_PTR(-EINVAL);
-
- *nr = btf_type_vlen(func_proto);
- if (*nr > 0)
- return (const struct btf_param *)(func_proto + 1);
- else
- return NULL;
-}
-
-#define BTF_ANON_STACK_MAX 16
-
-struct btf_anon_stack {
- u32 tid;
- u32 offset;
-};
-
-/*
- * Find a member of data structure/union by name and return it.
- * Return NULL if not found, or -EINVAL if parameter is invalid.
- * If the member is an member of anonymous union/structure, the offset
- * of that anonymous union/structure is stored into @anon_offset. Caller
- * can calculate the correct offset from the root data structure by
- * adding anon_offset to the member's offset.
- */
-const struct btf_member *btf_find_struct_member(struct btf *btf,
- const struct btf_type *type,
- const char *member_name,
- u32 *anon_offset)
-{
- struct btf_anon_stack *anon_stack;
- const struct btf_member *member;
- u32 tid, cur_offset = 0;
- const char *name;
- int i, top = 0;
-
- anon_stack = kcalloc(BTF_ANON_STACK_MAX, sizeof(*anon_stack), GFP_KERNEL);
- if (!anon_stack)
- return ERR_PTR(-ENOMEM);
-
-retry:
- if (!btf_type_is_struct(type)) {
- member = ERR_PTR(-EINVAL);
- goto out;
- }
-
- for_each_member(i, type, member) {
- if (!member->name_off) {
- /* Anonymous union/struct: push it for later use */
- type = btf_type_skip_modifiers(btf, member->type, &tid);
- if (type && top < BTF_ANON_STACK_MAX) {
- anon_stack[top].tid = tid;
- anon_stack[top++].offset =
- cur_offset + member->offset;
- }
- } else {
- name = btf_name_by_offset(btf, member->name_off);
- if (name && !strcmp(member_name, name)) {
- if (anon_offset)
- *anon_offset = cur_offset;
- goto out;
- }
- }
- }
- if (top > 0) {
- /* Pop from the anonymous stack and retry */
- tid = anon_stack[--top].tid;
- cur_offset = anon_stack[top].offset;
- type = btf_type_by_id(btf, tid);
- goto retry;
- }
- member = NULL;
-
-out:
- kfree(anon_stack);
- return member;
-}
-
diff --git a/kernel/trace/trace_btf.h b/kernel/trace/trace_btf.h
deleted file mode 100644
index 4bc44bc261e6..000000000000
--- a/kernel/trace/trace_btf.h
+++ /dev/null
@@ -1,11 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#include <linux/btf.h>
-
-const struct btf_type *btf_find_func_proto(const char *func_name,
- struct btf **btf_p);
-const struct btf_param *btf_get_func_param(const struct btf_type *func_proto,
- s32 *nr);
-const struct btf_member *btf_find_struct_member(struct btf *btf,
- const struct btf_type *type,
- const char *member_name,
- u32 *anon_offset);
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 4dc74d73fc1d..b33c424b8ee0 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -12,7 +12,7 @@
#define pr_fmt(fmt) "trace_probe: " fmt
#include <linux/bpf.h>
-#include "trace_btf.h"
+#include <linux/btf.h>
#include "trace_probe.h"
