bpf: Provide function to get vmlinux BTF information

It will be used later for BPF structure display support

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/1601292670-1616-2-git-send-email-alan.maguire@oracle.com

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index b89a307..e620a4b 100644 (file)
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1364,6 +1364,8 @@ 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 7ff05a7..2ee343d 100644 (file)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -11533,6 +11533,17 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
        return 0;
 }
 
+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)
 {
@@ -11566,12 +11577,7 @@ 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)