-Wmissing-prototypes warnings in user-mode linux

-Wmissing-prototypes warnings in user-mode linux

[Jani Nikula]

We're seeing a lot of -Wmissing-prototypes warnings when building
user-mode Linux. For example, our CI hits things like [1], and it's just
extra noise in the build.

I started adding some prototypes, but I lost my way around the arch/
subdirectory a bit. I'm not always quite sure what should or could be
included where, or whether a new header should be added instead, etc.,
so it wasn't going as quickly as I'd hoped.

Do you perhaps already have plans or, better yet, patches to address
this? Feels like it should be fairly quick for someone familiar with the
arch/um codebase.


BR,
Jani.


[1] https://lore.kernel.org/r/170963008487.503981.6735326012843985651@8e613ede5ea5



-- 
Jani Nikula, Intel

Re: -Wmissing-prototypes warnings in user-mode linux

[Johannes Berg]

On Tue, 2024-03-05 at 12:34 +0200, Jani Nikula wrote:
> We're seeing a lot of -Wmissing-prototypes warnings when building
> user-mode Linux. For example, our CI hits things like [1], and it's just
> extra noise in the build.

Yeah ...

> I started adding some prototypes, but I lost my way around the arch/
> subdirectory a bit. I'm not always quite sure what should or could be
> included where, or whether a new header should be added instead, etc.,
> so it wasn't going as quickly as I'd hoped.
> 
> Do you perhaps already have plans or, better yet, patches to address
> this? Feels like it should be fairly quick for someone familiar with the
> arch/um codebase.

I think this series addressed most already?

https://patchwork.ozlabs.org/project/linux-um/list/?series=393619

But I haven't checked myself yet.

johannes

Re: -Wmissing-prototypes warnings in user-mode linux

[Jani Nikula]

On Tue, 05 Mar 2024, Johannes Berg <johannes@sipsolutions.net> wrote:
> On Tue, 2024-03-05 at 12:34 +0200, Jani Nikula wrote:
>> We're seeing a lot of -Wmissing-prototypes warnings when building
>> user-mode Linux. For example, our CI hits things like [1], and it's just
>> extra noise in the build.
>
> Yeah ...
>
>> I started adding some prototypes, but I lost my way around the arch/
>> subdirectory a bit. I'm not always quite sure what should or could be
>> included where, or whether a new header should be added instead, etc.,
>> so it wasn't going as quickly as I'd hoped.
>> 
>> Do you perhaps already have plans or, better yet, patches to address
>> this? Feels like it should be fairly quick for someone familiar with the
>> arch/um codebase.
>
> I think this series addressed most already?
>
> https://patchwork.ozlabs.org/project/linux-um/list/?series=393619
>
> But I haven't checked myself yet.

Oh, nice, it certainly helps!

But after applying that in my branch, I do still get a bunch of
warnings.

BR,
Jani.



../arch/x86/um/user-offsets.c:17:6: warning: no previous prototype for ‘foo’ [-Wmissing-prototypes]
   17 | void foo(void)
      |      ^~~
In file included from ../arch/um/kernel/asm-offsets.c:1:
../arch/x86/um/shared/sysdep/kernel-offsets.h:9:6: warning: no previous prototype for ‘foo’ [-Wmissing-prototypes]
    9 | void foo(void)
      |      ^~~
../arch/x86/um/os-Linux/registers.c:146:15: warning: no previous prototype for ‘get_thread_reg’ [-Wmissing-prototypes]
  146 | unsigned long get_thread_reg(int reg, jmp_buf *buf)
      |               ^~~~~~~~~~~~~~
../arch/x86/um/vdso/um_vdso.c:16:5: warning: no previous prototype for ‘__vdso_clock_gettime’ [-Wmissing-prototypes]
   16 | int __vdso_clock_gettime(clockid_t clock, struct __kernel_old_timespec *ts)
      |     ^~~~~~~~~~~~~~~~~~~~
../arch/x86/um/vdso/um_vdso.c:30:5: warning: no previous prototype for ‘__vdso_gettimeofday’ [-Wmissing-prototypes]
   30 | int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
      |     ^~~~~~~~~~~~~~~~~~~
../arch/x86/um/vdso/um_vdso.c:44:21: warning: no previous prototype for ‘__vdso_time’ [-Wmissing-prototypes]
   44 | __kernel_old_time_t __vdso_time(__kernel_old_time_t *t)
      |                     ^~~~~~~~~~~
../arch/x86/um/vdso/um_vdso.c:57:1: warning: no previous prototype for ‘__vdso_getcpu’ [-Wmissing-prototypes]
   57 | __vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
      | ^~~~~~~~~~~~~
../arch/x86/um/ptrace_64.c:111:5: warning: no previous prototype for ‘poke_user’ [-Wmissing-prototypes]
  111 | int poke_user(struct task_struct *child, long addr, long data)
      |     ^~~~~~~~~
../arch/x86/um/ptrace_64.c:171:5: warning: no previous prototype for ‘peek_user’ [-Wmissing-prototypes]
  171 | int peek_user(struct task_struct *child, long addr, long data)
      |     ^~~~~~~~~
../arch/x86/um/signal.c:560:6: warning: no previous prototype for ‘sys_rt_sigreturn’ [-Wmissing-prototypes]
  560 | long sys_rt_sigreturn(void)
      |      ^~~~~~~~~~~~~~~~
../arch/um/os-Linux/skas/process.c:107:6: warning: no previous prototype for ‘wait_stub_done’ [-Wmissing-prototypes]
  107 | void wait_stub_done(int pid)
      |      ^~~~~~~~~~~~~~
../arch/um/os-Linux/skas/process.c:683:6: warning: no previous prototype for ‘__switch_mm’ [-Wmissing-prototypes]
  683 | void __switch_mm(struct mm_id *mm_idp)
      |      ^~~~~~~~~~~
../arch/um/kernel/um_arch.c:408:19: warning: no previous prototype for ‘read_initrd’ [-Wmissing-prototypes]
  408 | int __init __weak read_initrd(void)
      |                   ^~~~~~~~~~~
../arch/um/kernel/um_arch.c:461:7: warning: no previous prototype for ‘text_poke’ [-Wmissing-prototypes]
  461 | void *text_poke(void *addr, const void *opcode, size_t len)
      |       ^~~~~~~~~
../arch/um/kernel/um_arch.c:473:6: warning: no previous prototype for ‘text_poke_sync’ [-Wmissing-prototypes]
  473 | void text_poke_sync(void)
      |      ^~~~~~~~~~~~~~
../arch/um/os-Linux/main.c:187:7: warning: no previous prototype for ‘__wrap_malloc’ [-Wmissing-prototypes]
  187 | void *__wrap_malloc(int size)
      |       ^~~~~~~~~~~~~
../arch/um/os-Linux/main.c:208:7: warning: no previous prototype for ‘__wrap_calloc’ [-Wmissing-prototypes]
  208 | void *__wrap_calloc(int n, int size)
      |       ^~~~~~~~~~~~~
../arch/um/os-Linux/main.c:222:6: warning: no previous prototype for ‘__wrap_free’ [-Wmissing-prototypes]
  222 | void __wrap_free(void *ptr)
      |      ^~~~~~~~~~~
../arch/um/os-Linux/mem.c:28:6: warning: no previous prototype for ‘kasan_map_memory’ [-Wmissing-prototypes]
   28 | void kasan_map_memory(void *start, size_t len)
      |      ^~~~~~~~~~~~~~~~
../arch/um/os-Linux/mem.c:212:13: warning: no previous prototype for ‘check_tmpexec’ [-Wmissing-prototypes]
  212 | void __init check_tmpexec(void)
      |             ^~~~~~~~~~~~~
../arch/x86/um/syscalls_64.c:48:6: warning: no previous prototype for ‘arch_switch_to’ [-Wmissing-prototypes]
   48 | void arch_switch_to(struct task_struct *to)
      |      ^~~~~~~~~~~~~~
../arch/um/os-Linux/start_up.c:301:12: warning: no previous prototype for ‘parse_iomem’ [-Wmissing-prototypes]
  301 | int __init parse_iomem(char *str, int *add)
      |            ^~~~~~~~~~~



-- 
Jani Nikula, Intel

Re: -Wmissing-prototypes warnings in user-mode linux

[Johannes Berg]

On Tue, 2024-03-05 at 12:49 +0200, Jani Nikula wrote:
> On Tue, 05 Mar 2024, Johannes Berg <johannes@sipsolutions.net> wrote:
> > On Tue, 2024-03-05 at 12:34 +0200, Jani Nikula wrote:
> > > We're seeing a lot of -Wmissing-prototypes warnings when building
> > > user-mode Linux. For example, our CI hits things like [1], and it's just
> > > extra noise in the build.
> > 
> > Yeah ...
> > 
> > > I started adding some prototypes, but I lost my way around the arch/
> > > subdirectory a bit. I'm not always quite sure what should or could be
> > > included where, or whether a new header should be added instead, etc.,
> > > so it wasn't going as quickly as I'd hoped.
> > > 
> > > Do you perhaps already have plans or, better yet, patches to address
> > > this? Feels like it should be fairly quick for someone familiar with the
> > > arch/um codebase.
> > 
> > I think this series addressed most already?
> > 
> > https://patchwork.ozlabs.org/project/linux-um/list/?series=393619
> > 
> > But I haven't checked myself yet.
> 
> Oh, nice, it certainly helps!
> 
> But after applying that in my branch, I do still get a bunch of
> warnings.
> 

I cleaned up the patchwork a bit now, but looks like we don't have
anything else yet :)

johannes

Re: -Wmissing-prototypes warnings in user-mode linux

[Tiwei Bie]

On 3/5/24 6:49 PM, Jani Nikula wrote:
> On Tue, 05 Mar 2024, Johannes Berg <johannes@sipsolutions.net> wrote:
>> On Tue, 2024-03-05 at 12:34 +0200, Jani Nikula wrote:
>>> We're seeing a lot of -Wmissing-prototypes warnings when building
>>> user-mode Linux. For example, our CI hits things like [1], and it's just
>>> extra noise in the build.
>>
>> Yeah ...
>>
>>> I started adding some prototypes, but I lost my way around the arch/
>>> subdirectory a bit. I'm not always quite sure what should or could be
>>> included where, or whether a new header should be added instead, etc.,
>>> so it wasn't going as quickly as I'd hoped.
>>>
>>> Do you perhaps already have plans or, better yet, patches to address
>>> this? Feels like it should be fairly quick for someone familiar with the
>>> arch/um codebase.
>>
>> I think this series addressed most already?
>>
>> https://patchwork.ozlabs.org/project/linux-um/list/?series=393619
>>
>> But I haven't checked myself yet.
> 
> Oh, nice, it certainly helps!
> 
> But after applying that in my branch, I do still get a bunch of
> warnings.

Thanks for raising this topic!                            
                                                              
Indeed. To make it easier to review, the current series only addressed
the -Wmissing-prototypes warnings that can be fixed straightforwardly (e.g.
by turning into static functions or including missing headers). The remaining 
-Wmissing-prototypes warnings mainly fall into the following categories:

- Symbols defined and used in os-Linux/;                
- Symbols defined in os-Linux/, but declared in kernel headers;
- Symbols defined in individual files and not called explicitly;

My plan was to fix the remaining warnings in followup series. Ultimately,
I wish we can let cc treat -Wmissing-prototypes warnings as errors.

Regards,
Tiwei

Re: -Wmissing-prototypes warnings in user-mode linux

[Jani Nikula]

On Tue, 05 Mar 2024, Tiwei Bie <tiwei.btw@antgroup.com> wrote:
> Thanks for raising this topic!                            
>                                                               
> Indeed. To make it easier to review, the current series only addressed
> the -Wmissing-prototypes warnings that can be fixed straightforwardly (e.g.
> by turning into static functions or including missing headers). The remaining 
> -Wmissing-prototypes warnings mainly fall into the following categories:
>
> - Symbols defined and used in os-Linux/;                
> - Symbols defined in os-Linux/, but declared in kernel headers;
> - Symbols defined in individual files and not called explicitly;
>
> My plan was to fix the remaining warnings in followup series. Ultimately,
> I wish we can let cc treat -Wmissing-prototypes warnings as errors.

Yay! That's good to hear.

If you want to get build testing from our CI, using our configs, please
just Cc: intel-xe@lists.freedesktop.org when sending the patches. You'll
get the results in reply.


Thanks,
Jani.

-- 
Jani Nikula, Intel

Re: -Wmissing-prototypes warnings in user-mode linux

[Tiwei Bie]

On 3/5/24 9:45 PM, Jani Nikula wrote:
> On Tue, 05 Mar 2024, Tiwei Bie <tiwei.btw@antgroup.com> wrote:
>> Thanks for raising this topic!                            
>>                                                               
>> Indeed. To make it easier to review, the current series only addressed
>> the -Wmissing-prototypes warnings that can be fixed straightforwardly (e.g.
>> by turning into static functions or including missing headers). The remaining 
>> -Wmissing-prototypes warnings mainly fall into the following categories:
>>
>> - Symbols defined and used in os-Linux/;                
>> - Symbols defined in os-Linux/, but declared in kernel headers;
>> - Symbols defined in individual files and not called explicitly;
>>
>> My plan was to fix the remaining warnings in followup series. Ultimately,
>> I wish we can let cc treat -Wmissing-prototypes warnings as errors.
> 
> Yay! That's good to hear.
> 
> If you want to get build testing from our CI, using our configs, please
> just Cc: intel-xe@lists.freedesktop.org when sending the patches. You'll
> get the results in reply.

Cool. Will Cc the list in the future. Thanks! :)

Regards,
Tiwei

Re: -Wmissing-prototypes warnings in user-mode linux

[Richard Weinberger]

----- Ursprüngliche Mail -----
> Von: "Jani Nikula" <jani.nikula@intel.com>
> An: "Johannes Berg" <johannes@sipsolutions.net>, "richard" <richard@nod.at>, "anton ivanov"
>> I think this series addressed most already?
>>
>> https://patchwork.ozlabs.org/project/linux-um/list/?series=393619
>>
>> But I haven't checked myself yet.
> 
> Oh, nice, it certainly helps!
> 
> But after applying that in my branch, I do still get a bunch of
> warnings.

Exactly.

Tiwei Bie, with your v3 series[0] applied,
I still see the following build warnings:
arch/x86/um/signal.c:559:6: warning: no previous prototype for ‘sys_rt_sigreturn’ [-Wmissing-prototypes]
  559 | long sys_rt_sigreturn(void)
      |      ^~~~~~~~~~~~~~~~
arch/um/os-Linux/mem.c:28:6: warning: no previous prototype for ‘kasan_map_memory’ [-Wmissing-prototypes]
   28 | void kasan_map_memory(void *start, size_t len)
      |      ^~~~~~~~~~~~~~~~
arch/um/os-Linux/mem.c:212:13: warning: no previous prototype for ‘check_tmpexec’ [-Wmissing-prototypes]
  212 | void __init check_tmpexec(void)
      |             ^~~~~~~~~~~~~
arch/x86/um/os-Linux/registers.c:146:15: warning: no previous prototype for ‘get_thread_reg’ [-Wmissing-prototypes]
  146 | unsigned long get_thread_reg(int reg, jmp_buf *buf)
      |               ^~~~~~~~~~~~~~
arch/um/os-Linux/skas/process.c:107:6: warning: no previous prototype for ‘wait_stub_done’ [-Wmissing-prototypes]
  107 | void wait_stub_done(int pid)
      |      ^~~~~~~~~~~~~~
arch/um/os-Linux/skas/process.c:683:6: warning: no previous prototype for ‘__switch_mm’ [-Wmissing-prototypes]
  683 | void __switch_mm(struct mm_id *mm_idp)
      |      ^~~~~~~~~~~
arch/x86/um/vdso/um_vdso.c:16:5: warning: no previous prototype for ‘__vdso_clock_gettime’ [-Wmissing-prototypes]
   16 | int __vdso_clock_gettime(clockid_t clock, struct __kernel_old_timespec *ts)
      |     ^~~~~~~~~~~~~~~~~~~~
arch/x86/um/vdso/um_vdso.c:30:5: warning: no previous prototype for ‘__vdso_gettimeofday’ [-Wmissing-prototypes]
   30 | int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
      |     ^~~~~~~~~~~~~~~~~~~
arch/x86/um/vdso/um_vdso.c:44:21: warning: no previous prototype for ‘__vdso_time’ [-Wmissing-prototypes]
   44 | __kernel_old_time_t __vdso_time(__kernel_old_time_t *t)
      |                     ^~~~~~~~~~~
arch/x86/um/vdso/um_vdso.c:57:1: warning: no previous prototype for ‘__vdso_getcpu’ [-Wmissing-prototypes]
   57 | __vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
      | ^~~~~~~~~~~~~

[0] https://patchwork.ozlabs.org/project/linux-um/list/?series=397986

Thanks,
//richard

Re: -Wmissing-prototypes warnings in user-mode linux

[Tiwei Bie]

Hi Richard,

On 4/23/24 4:35 AM, Richard Weinberger wrote:
> ----- Ursprüngliche Mail -----
>> Von: "Jani Nikula" <jani.nikula@intel.com>
>> An: "Johannes Berg" <johannes@sipsolutions.net>, "richard" <richard@nod.at>, "anton ivanov"
>>> I think this series addressed most already?
>>>
>>> https://patchwork.ozlabs.org/project/linux-um/list/?series=393619
>>>
>>> But I haven't checked myself yet.
>>
>> Oh, nice, it certainly helps!
>>
>> But after applying that in my branch, I do still get a bunch of
>> warnings.
> 
> Exactly.
> 
> Tiwei Bie, with your v3 series[0] applied,
> I still see the following build warnings:

Thanks for trying that series! As stated in its cover letter [0], some
remaining -Wmissing-prototypes warnings are as expected.

That series includes only the straightforward fixes and has addressed
a large portion of the -Wmissing-prototypes warnings.

I plan to fix the remaining warnings in a separate smaller followup series.
But the fixes in it might not be as straightforward, and some might be
contentious. I will post it tonight or tomorrow.

[0] https://patchwork.ozlabs.org/project/linux-um/cover/20240306101925.1088870-1-tiwei.btw@antgroup.com/

Regards,
Tiwei

> arch/x86/um/signal.c:559:6: warning: no previous prototype for ‘sys_rt_sigreturn’ [-Wmissing-prototypes]
>   559 | long sys_rt_sigreturn(void)
>       |      ^~~~~~~~~~~~~~~~
> arch/um/os-Linux/mem.c:28:6: warning: no previous prototype for ‘kasan_map_memory’ [-Wmissing-prototypes]
>    28 | void kasan_map_memory(void *start, size_t len)
>       |      ^~~~~~~~~~~~~~~~
> arch/um/os-Linux/mem.c:212:13: warning: no previous prototype for ‘check_tmpexec’ [-Wmissing-prototypes]
>   212 | void __init check_tmpexec(void)
>       |             ^~~~~~~~~~~~~
> arch/x86/um/os-Linux/registers.c:146:15: warning: no previous prototype for ‘get_thread_reg’ [-Wmissing-prototypes]
>   146 | unsigned long get_thread_reg(int reg, jmp_buf *buf)
>       |               ^~~~~~~~~~~~~~
> arch/um/os-Linux/skas/process.c:107:6: warning: no previous prototype for ‘wait_stub_done’ [-Wmissing-prototypes]
>   107 | void wait_stub_done(int pid)
>       |      ^~~~~~~~~~~~~~
> arch/um/os-Linux/skas/process.c:683:6: warning: no previous prototype for ‘__switch_mm’ [-Wmissing-prototypes]
>   683 | void __switch_mm(struct mm_id *mm_idp)
>       |      ^~~~~~~~~~~
> arch/x86/um/vdso/um_vdso.c:16:5: warning: no previous prototype for ‘__vdso_clock_gettime’ [-Wmissing-prototypes]
>    16 | int __vdso_clock_gettime(clockid_t clock, struct __kernel_old_timespec *ts)
>       |     ^~~~~~~~~~~~~~~~~~~~
> arch/x86/um/vdso/um_vdso.c:30:5: warning: no previous prototype for ‘__vdso_gettimeofday’ [-Wmissing-prototypes]
>    30 | int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
>       |     ^~~~~~~~~~~~~~~~~~~
> arch/x86/um/vdso/um_vdso.c:44:21: warning: no previous prototype for ‘__vdso_time’ [-Wmissing-prototypes]
>    44 | __kernel_old_time_t __vdso_time(__kernel_old_time_t *t)
>       |                     ^~~~~~~~~~~
> arch/x86/um/vdso/um_vdso.c:57:1: warning: no previous prototype for ‘__vdso_getcpu’ [-Wmissing-prototypes]
>    57 | __vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
>       | ^~~~~~~~~~~~~
> 
> [0] https://patchwork.ozlabs.org/project/linux-um/list/?series=397986
> 
> Thanks,
> //richard