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From:   Artem Savkov <asavkov@redhat.com>
To:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>, bpf@vger.kernel.org,
        netdev@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org,
        Andrea Arcangeli <aarcange@redhat.com>,
        Daniel Vacek <dvacek@redhat.com>,
        Jiri Olsa <olsajiri@gmail.com>, Song Liu <song@kernel.org>,
        Daniel Xu <dxu@dxuuu.xyz>,
        Kumar Kartikeya Dwivedi <memxor@gmail.com>,
        Artem Savkov <asavkov@redhat.com>
Subject: [PATCH bpf-next v4 2/3] bpf: export crash_kexec() as destructive kfunc
Date:   Tue,  9 Aug 2022 12:53:16 +0200
Message-Id: <20220809105317.436682-3-asavkov@redhat.com>
In-Reply-To: <20220809105317.436682-1-asavkov@redhat.com>
References: <20220809105317.436682-1-asavkov@redhat.com>
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Allow properly marked bpf programs to call crash_kexec().

Signed-off-by: Artem Savkov <asavkov@redhat.com>
---
 kernel/bpf/helpers.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 1f961f9982d2..103dbddff41f 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -1711,3 +1711,24 @@ 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)
+{
+	if (register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &tracing_kfunc_set))
+		pr_warn("failed to register kfunc id set for BPF_PROG_TYPE_TRACING\n");
+
+	return 0;
+}
+
+late_initcall(kfunc_init);
-- 
2.37.1