Re: [PATCH] powerpc: Fix missing prototype problems for "arch/powerpc/kernel/setup_64.c"

["Cédric Le Goater" <clg@kaod.org>]

On 3/15/21 2:01 PM, Christophe Leroy wrote:
> 
> 
> Le 15/03/2021 à 13:57, Cédric Le Goater a écrit :
>> On 3/15/21 1:48 PM, heying (H) wrote:
>>>
>>> 在 2021/3/15 20:17, Christophe Leroy 写道:
>>>> You subject doesn't match the content of the patch.
>>> OK. I'll adapt that.
>>>>
>>>> Le 15/03/2021 à 13:04, He Ying a écrit :
>>>>> The variables 'uaccess_fulsh' and 'entry_flush' are not referenced
>>>>> outside the file. So define them as static to avoid the warnings.
>>>>>
>>>>> And add a prototype for the function 'panic_smp_self_stop' for the
>>>>> same purpose.
>>>>>
>>>>> Sparse also warns that 'rfi_flush' should be static. However, it's
>>>>> referenced outside the file.
>>>>
>>>> To clear that warning, you have to include asm/security_features.h, rfi_flush is declared there.
>>> Do you mean that I should include this header in arch/powerpc/kernel/setup_64.c?
>>
>> yes.
>>
>>>>
>>>>>
>>>>> The warnings about the file reported by sparse are as follows:
>>>>> arch/powerpc/kernel/setup_64.c:422:6: warning: symbol 'panic_smp_self_stop' was not declared. Should it be static?
>>>>> arch/powerpc/kernel/setup_64.c:951:6: warning: symbol 'rfi_flush' was not declared. Should it be static?
>>>>> arch/powerpc/kernel/setup_64.c:952:6: warning: symbol 'entry_flush' was not declared. Should it be static?
>>>>> arch/powerpc/kernel/setup_64.c:953:6: warning: symbol 'uaccess_flush' was not declared. Should it be static?
>>>>>
>>>>> Reported-by: Hulk Robot <hulkci@huawei.com>
>>>>> Signed-off-by: He Ying <heying24@huawei.com>
>>>>> ---
>>>>>    arch/powerpc/kernel/setup_64.c | 6 ++++--
>>>>>    1 file changed, 4 insertions(+), 2 deletions(-)
>>>>>
>>>>> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
>>>>> index 560ed8b975e7..603aacd8527b 100644
>>>>> --- a/arch/powerpc/kernel/setup_64.c
>>>>> +++ b/arch/powerpc/kernel/setup_64.c
>>>>> @@ -71,6 +71,8 @@
>>>>>      #include "setup.h"
>>>>>    +extern void panic_smp_self_stop(void);
>>>>> +
>>>>
>>>> For function prototypes 'extern' is unneeded and deprecated.
>>>>
>>>> And function prototypes should go in an header file.
>>>>
>>>> panic_smp_self_stop() is called from kernel/panic.c , it should be declared in one of the generic linux header files I think.
>>> Yes, you're right. But I have no idea which header it should be declared in. May I have your suggestions?
>>
>> arch/powerpc/include/asm/bug.h looks like a good place.
> 
> Why declaring it in a powerpc header ?
> 
> It's a weak function defined in core part of kernel (kernel/panic.c).
> 
> I think it should go in a common header, just like for instance arch_thaw_secondary_cpus_begin()

Indeed. include/linux/smp.h is a better place for a common routine.

C.