Re: arch/sh/boot/compressed/misc.c:118:6: warning: no previous prototype for 'arch_ftrace_ops_list_func'

[Steven Rostedt]

On Tue, 31 Oct 2023 06:15:04 +0800
kernel test robot <lkp@xxxxxxxxx> wrote:

> Hi Steven,
> 
> FYI, the error/warning still remains.
> 
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   14ab6d425e80674b6a0145f05719b11e82e64824
> commit: 17b251a290ba84a0c2c5c82df9596cb2e7207ca6 ftrace/sh: Add arch_ftrace_ops_list_func stub to have compressed image still link
> date:   2 years ago
> config: sh-allnoconfig (https://download.01.org/0day-ci/archive/20231031/202310310611.5RteDpO7-lkp@xxxxxxxxx/config)
> compiler: sh4-linux-gcc (GCC) 13.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231031/202310310611.5RteDpO7-lkp@xxxxxxxxx/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202310310611.5RteDpO7-lkp@xxxxxxxxx/
> 
> All warnings (new ones prefixed by >>):
> 
>    arch/sh/boot/compressed/misc.c:109:6: warning: no previous prototype for '__stack_chk_fail' [-Wmissing-prototypes]
>      109 | void __stack_chk_fail(void)
>          |      ^~~~~~~~~~~~~~~~
>    arch/sh/boot/compressed/misc.c:115:6: warning: no previous prototype for 'ftrace_stub' [-Wmissing-prototypes]
>      115 | void ftrace_stub(void)
>          |      ^~~~~~~~~~~
> >> arch/sh/boot/compressed/misc.c:118:6: warning: no previous prototype for 'arch_ftrace_ops_list_func' [-Wmissing-prototypes]  
>      118 | void arch_ftrace_ops_list_func(void)
>          |      ^~~~~~~~~~~~~~~~~~~~~~~~~

As the comment states, this is needed only because the linker script
vmlinux.lds.h references them, and it will not build without it.

If someone really cares, they could simply add a header to quiet these
warnings, but seriously, these functions are just stubs to allow the sh
boot portion use the vmlinux.lds.h linker script. These stubs are only for
satisfying linker references and are not used. I'm not going to be the one
to bother "fixing" it.

-- Steve


>    arch/sh/boot/compressed/misc.c:128:6: warning: no previous prototype for 'decompress_kernel' [-Wmissing-prototypes]
>      128 | void decompress_kernel(void)
>          |      ^~~~~~~~~~~~~~~~~
> 
> 
> vim +/arch_ftrace_ops_list_func +118 arch/sh/boot/compressed/misc.c
> 
>    113	
>    114	/* Needed because vmlinux.lds.h references this */
>    115	void ftrace_stub(void)
>    116	{
>    117	}
>  > 118	void arch_ftrace_ops_list_func(void)  
>    119	{
>    120	}
>    121	
>