On Fri, 6 Sep 2024 11:49:10 +0800
Zheng Yejian <[email protected]> wrote:
> > diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
> > index c47422b20908..f2021ab52da2 100644
> > --- a/kernel/trace/trace_entries.h
> > +++ b/kernel/trace/trace_entries.h
> > @@ -61,8 +61,11 @@ FTRACE_ENTRY_REG(function, ftrace_entry,
> > TRACE_FN,
> >
> > F_STRUCT(
> > - __field_fn( unsigned long, ip )
> > - __field_fn( unsigned long, parent_ip )
> > + __field_fn( unsigned long, ip )
> > + __field_fn( unsigned long, parent_ip )
> > +#ifdef CONFIG_FUNCTION_TRACE_ARGS
> > + __field_struct( struct ftrace_regs, regs )
>
> Only function arguments are printed, they are several registers in
> ftrace_regs,
> would it be better to store what are needed?
> Although different archs save function arguments in different registers, store
> the entire ftrace_regs are much more simple..
Agreed, and I stated as much in my reply to patch 6.
This too will need two versions of the event. One will be function the
other will be function_args. And it will only record the necessary
arguments not the full ftrace_regs structure, as I plan on making that
structure have "zero size".
>
> > +#endif
> > ),
> >
> > F_printk(" %ps <-- %ps",
>
> F_printk should also match F_STRUCT, otherwise 'format' info may be incorrect,
> it may confuse data parsing in user tools.
Well, it will just ignore the struct part, as its not listed.
-- Steve
>
> > diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
> > index 3b0cea37e029..7ff651a0b45a 100644
> > --- a/kernel/trace/trace_functions.c
> > +++ b/kernel/trace/trace_functions.c
> > @@ -25,6 +25,9 @@ static void
> > function_trace_call(unsigned long ip, unsigned long parent_ip,
> > struct ftrace_ops *op, struct ftrace_regs *fregs);
> > static void
> > +function_args_trace_call(unsigned long ip, unsigned long parent_ip,
> > + struct ftrace_ops *op, struct ftrace_regs *fregs);
