bpf: export crash_kexec() as destructive kfunc

Allow properly marked bpf programs to call crash_kexec().

Signed-off-by: Artem Savkov <asavkov@redhat.com>
Link: https://lore.kernel.org/r/20220810065905.475418-3-asavkov@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index a95eb9f..3c1b9bb 100644 (file)
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -1725,3 +1725,21 @@ bpf_base_func_proto(enum bpf_func_id func_id)
                return NULL;
        }
 }
+
+BTF_SET8_START(tracing_btf_ids)
+#ifdef CONFIG_KEXEC_CORE
+BTF_ID_FLAGS(func, crash_kexec, KF_DESTRUCTIVE)
+#endif
+BTF_SET8_END(tracing_btf_ids)
+
+static const struct btf_kfunc_id_set tracing_kfunc_set = {
+       .owner = THIS_MODULE,
+       .set   = &tracing_btf_ids,
+};
+
+static int __init kfunc_init(void)
+{
+       return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &tracing_kfunc_set);
+}
+
+late_initcall(kfunc_init);