[RFC,bpf-next,1/4] bpf: provide function to get vmlinux BTF information

Commit Message

Alan Maguire Aug. 6, 2020, 2:42 p.m. UTC

It will be used later for BPF structure display support

Signed-off-by: Alan Maguire <[e-mail]>
---
 include/linux/bpf.h   |  2 ++
 kernel/bpf/verifier.c | 18 ++++++++++++------
 2 files changed, 14 insertions(+), 6 deletions(-)

Patch

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index cef4ef0..55eb67d 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1290,6 +1290,8 @@  int bpf_check(struct bpf_prog **fp, union bpf_attr *attr,
 	      union bpf_attr __user *uattr);
 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth);
 
+struct btf *bpf_get_btf_vmlinux(void);
+
 /* Map specifics */
 struct xdp_buff;
 struct sk_buff;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index b6ccfce..05dfc41 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -11064,6 +11064,17 @@  static int check_attach_btf_id(struct bpf_verifier_env *env)
 	}
 }
 
+struct btf *bpf_get_btf_vmlinux(void)
+{
+	if (!btf_vmlinux && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
+		mutex_lock(&bpf_verifier_lock);
+		if (!btf_vmlinux)
+			btf_vmlinux = btf_parse_vmlinux();
+		mutex_unlock(&bpf_verifier_lock);
+	}
+	return btf_vmlinux;
+}
+
 int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
 	      union bpf_attr __user *uattr)
 {
@@ -11097,12 +11108,7 @@  int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
 	env->ops = bpf_verifier_ops[env->prog->type];
 	is_priv = bpf_capable();
 
-	if (!btf_vmlinux && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
-		mutex_lock(&bpf_verifier_lock);
-		if (!btf_vmlinux)
-			btf_vmlinux = btf_parse_vmlinux();
-		mutex_unlock(&bpf_verifier_lock);
-	}
+	bpf_get_btf_vmlinux();
 
 	/* grab the mutex to protect few globals used by verifier */
 	if (!is_priv)