bpf: Add __bpf_hook_{start,end} macros
Not all uses of __diag_ignore_all(...) in BPF-related code in order to
suppress warnings are wrapping kfunc definitions. Some "hook point"
definitions - small functions meant to be used as attach points for
fentry and similar BPF progs - need to suppress -Wmissing-declarations.
We could use __bpf_kfunc_{start,end}_defs added in the previous patch in
such cases, but this might be confusing to someone unfamiliar with BPF
internals. Instead, this patch adds __bpf_hook_{start,end} macros,
currently having the same effect as __bpf_kfunc_{start,end}_defs, then
uses them to suppress warnings for two hook points in the kernel itself
and some bpf_testmod hook points as well.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20231031215625.2343848-2-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index d80d7a6..c0adb72 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -156,19 +156,16 @@ static struct cgroup *cgroup_rstat_cpu_pop_updated(struct cgroup *pos,
* optimize away the callsite. Therefore, __weak is needed to ensure that the
* call is still emitted, by telling the compiler that we don't know what the
* function might eventually be.
- *
- * __diag_* below are needed to dismiss the missing prototype warning.
*/
-__diag_push();
-__diag_ignore_all("-Wmissing-prototypes",
- "kfuncs which will be used in BPF programs");
+
+__bpf_hook_start();
__weak noinline void bpf_rstat_flush(struct cgroup *cgrp,
struct cgroup *parent, int cpu)
{
}
-__diag_pop();
+__bpf_hook_end();
/* see cgroup_rstat_flush() */
static void cgroup_rstat_flush_locked(struct cgroup *cgrp)
