[PATCH v6 bpf-next 1/6] bpf: provide function to get vmlinux BTF information

From: Alan Maguire
Date: Wed Sep 23 2020 - 13:49:50 EST


It will be used later for BPF structure display support

Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
---
include/linux/bpf.h | 2 ++
kernel/bpf/verifier.c | 18 ++++++++++++------
2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index fc5c901..049e50f 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1340,6 +1340,8 @@ 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 15ab889b..092ffd6 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -11488,6 +11488,17 @@ 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)
{
@@ -11521,12 +11532,7 @@ 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)
--
1.8.3.1