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

[Steven Rostedt]

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,