Re: [PATCH v7 22/36] function_graph: Add a new entry handler with parent_ip and ftrace_regs

[Steven Rostedt]

On Wed,  7 Feb 2024 00:11:34 +0900
"Masami Hiramatsu (Google)" <mhira...@kernel.org> wrote:

> From: Masami Hiramatsu (Google) <mhira...@kernel.org>
> 
> Add a new entry handler to fgraph_ops as 'entryregfunc'  which takes
> parent_ip and ftrace_regs. Note that the 'entryfunc' and 'entryregfunc'
> are mutual exclusive. You can set only one of them.
> 
> Signed-off-by: Masami Hiramatsu (Google) <mhira...@kernel.org>
> ---

>  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
> @@ -1070,6 +1075,7 @@ extern int ftrace_graph_entry_stub(struct 
> ftrace_graph_ent *trace, struct fgraph
>  struct fgraph_ops {
>       trace_func_graph_ent_t          entryfunc;
>       trace_func_graph_ret_t          retfunc;
> +     trace_func_graph_regs_ent_t     entryregfunc;

if entryfunc and entryregfunc are mutually exclusive, then why not make them
into a union?

struct fgraph_ops {
        union {
                trace_func_graph_ent_t          entryfunc;
                trace_func_graph_regs_ent_t     entryregfunc;
        };
        trace_func_graph_ret_t          retfunc;

-- Steve

        

>       struct ftrace_ops               ops; /* for the hash lists */
>       void                            *private;
>       int                             idx;