Re: [PATCH] nds32: ftrace: fix pointer comparison warning

[Randy Dunlap]

On 10/27/21 4:59 AM, Steven Rostedt wrote:
> On Tue, 26 Oct 2021 22:55:54 -0700
> Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
>
> > GCC 11.1.0 for nds32 (nds32le if it matters) complains:
> >
> > ../arch/nds32/kernel/ftrace.c: In function '_mcount':
> > ../arch/nds32/kernel/ftrace.c:24:35: error: comparison of distinct pointer types lacks a cast [-Werror]
> >     24 |         if (ftrace_trace_function != ftrace_stub)
> >        |                                   ^~
> >
> > Cast the second function (pointer) to (void *) to avoid the warning.
> >
> > Fixes: a18082575c66 ("nds32/ftrace: Support static function tracer")
> > Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > To: Greentime Hu <green.hu@xxxxxxxxx>
> > Cc: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
> > Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> > Cc: Zong Li <zong@xxxxxxxxxxxxx>
> > Cc: Nick Hu <nickhu@xxxxxxxxxxxxx>
> > Cc: Vincent Chen <deanbo422@xxxxxxxxx>
> > ---
> >   arch/nds32/kernel/ftrace.c |    2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > --- linux-next-20211026.orig/arch/nds32/kernel/ftrace.c
> > +++ linux-next-20211026/arch/nds32/kernel/ftrace.c
> > @@ -21,7 +21,7 @@ noinline void _mcount(unsigned long pare
> >   
> >   	unsigned long ip = (unsigned long)__builtin_return_address(0);
> >   
> > -	if (ftrace_trace_function != ftrace_stub)
> > +	if (ftrace_trace_function != (void *)ftrace_stub)
> >   		ftrace_trace_function(ip - MCOUNT_INSN_SIZE, parent_ip,
> >   				      NULL, NULL);
> >   
>
> Or update ftrace_trace_function prototype that was missed when ftrace_stub
> prototype was updated.
>
> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
> ---
> diff --git a/arch/nds32/kernel/ftrace.c b/arch/nds32/kernel/ftrace.c
> index f0ef4842d191..711bc8cd186d 100644
> --- a/arch/nds32/kernel/ftrace.c
> +++ b/arch/nds32/kernel/ftrace.c
> @@ -6,7 +6,7 @@
>   
>   #ifndef CONFIG_DYNAMIC_FTRACE
>   extern void (*ftrace_trace_function)(unsigned long, unsigned long,
> -				     struct ftrace_ops*, struct pt_regs*);
> +				     struct ftrace_ops*, struct ftrace_regs*);
>   extern void ftrace_graph_caller(void);
>   
>   noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,

OK, looks good.

Thanks.

--
~Randy