[PATCH] x86/irqflags: mark native_restore_fl extern inline

[PATCH] x86/irqflags: mark native_restore_fl extern inline

[Nick Desaulniers]

Fixes commit 208cbb325589 ("x86/irqflags: Provide a declaration for
native_save_fl")

This should have been marked extern inline in order to pick up the out
of line definition in arch/x86/kernel/irqflags.S.

Cc: stable@vger.kernel.org # 4.18, 4.14, 4.9, 4.4
Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
 arch/x86/include/asm/irqflags.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index c14f2a74b2be..15450a675031 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -33,7 +33,8 @@ extern inline unsigned long native_save_fl(void)
 	return flags;
 }
 
-static inline void native_restore_fl(unsigned long flags)
+extern inline void native_restore_fl(unsigned long flags);
+extern inline void native_restore_fl(unsigned long flags)
 {
 	asm volatile("push %0 ; popf"
 		     : /* no output */
-- 
2.19.0.rc0.228.g281dcd1b4d0-goog

Re: [PATCH] x86/irqflags: mark native_restore_fl extern inline

[Greg Kroah-Hartman]

On Mon, Aug 27, 2018 at 02:40:09PM -0700, Nick Desaulniers wrote:
> Fixes commit 208cbb325589 ("x86/irqflags: Provide a declaration for
> native_save_fl")
> 
> This should have been marked extern inline in order to pick up the out
> of line definition in arch/x86/kernel/irqflags.S.
> 
> Cc: stable@vger.kernel.org # 4.18, 4.14, 4.9, 4.4
> Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
>  arch/x86/include/asm/irqflags.h | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
> index c14f2a74b2be..15450a675031 100644
> --- a/arch/x86/include/asm/irqflags.h
> +++ b/arch/x86/include/asm/irqflags.h
> @@ -33,7 +33,8 @@ extern inline unsigned long native_save_fl(void)
>  	return flags;
>  }
>  
> -static inline void native_restore_fl(unsigned long flags)
> +extern inline void native_restore_fl(unsigned long flags);
> +extern inline void native_restore_fl(unsigned long flags)

This looks odd to me, but my coffee hasn't kicked in yet this morning.
Why do you need both lines here?  Shouldn't the actual function be
sufficient?  If not, a comment explaining this would be nice.

thanks,

greg k-h

Re: [PATCH] x86/irqflags: mark native_restore_fl extern inline

[Juergen Gross]

On 27/08/18 23:40, Nick Desaulniers wrote:
> Fixes commit 208cbb325589 ("x86/irqflags: Provide a declaration for
> native_save_fl")
> 
> This should have been marked extern inline in order to pick up the out
> of line definition in arch/x86/kernel/irqflags.S.
> 
> Cc: stable@vger.kernel.org # 4.18, 4.14, 4.9, 4.4
> Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

Reviewed-by: Juergen Gross <jgross@suse.com>


Juergen

Re: [PATCH] x86/irqflags: mark native_restore_fl extern inline

[Juergen Gross]

On 28/08/18 07:13, Greg Kroah-Hartman wrote:
> On Mon, Aug 27, 2018 at 02:40:09PM -0700, Nick Desaulniers wrote:
>> Fixes commit 208cbb325589 ("x86/irqflags: Provide a declaration for
>> native_save_fl")
>>
>> This should have been marked extern inline in order to pick up the out
>> of line definition in arch/x86/kernel/irqflags.S.
>>
>> Cc: stable@vger.kernel.org # 4.18, 4.14, 4.9, 4.4
>> Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
>> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
>> ---
>>  arch/x86/include/asm/irqflags.h | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
>> index c14f2a74b2be..15450a675031 100644
>> --- a/arch/x86/include/asm/irqflags.h
>> +++ b/arch/x86/include/asm/irqflags.h
>> @@ -33,7 +33,8 @@ extern inline unsigned long native_save_fl(void)
>>  	return flags;
>>  }
>>  
>> -static inline void native_restore_fl(unsigned long flags)
>> +extern inline void native_restore_fl(unsigned long flags);
>> +extern inline void native_restore_fl(unsigned long flags)
> 
> This looks odd to me, but my coffee hasn't kicked in yet this morning.
> Why do you need both lines here?  Shouldn't the actual function be
> sufficient?  If not, a comment explaining this would be nice.

Look just some lines further up:

/* Declaration required for gcc < 4.9 to prevent
-Werror=missing-prototypes */
extern inline unsigned long native_save_fl(void);
extern inline unsigned long native_save_fl(void)


Juergen

Re: [PATCH] x86/irqflags: mark native_restore_fl extern inline

[Greg Kroah-Hartman]

On Tue, Aug 28, 2018 at 08:02:37AM +0200, Juergen Gross wrote:
> On 28/08/18 07:13, Greg Kroah-Hartman wrote:
> > On Mon, Aug 27, 2018 at 02:40:09PM -0700, Nick Desaulniers wrote:
> >> Fixes commit 208cbb325589 ("x86/irqflags: Provide a declaration for
> >> native_save_fl")
> >>
> >> This should have been marked extern inline in order to pick up the out
> >> of line definition in arch/x86/kernel/irqflags.S.
> >>
> >> Cc: stable@vger.kernel.org # 4.18, 4.14, 4.9, 4.4
> >> Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
> >> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> >> ---
> >>  arch/x86/include/asm/irqflags.h | 3 ++-
> >>  1 file changed, 2 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
> >> index c14f2a74b2be..15450a675031 100644
> >> --- a/arch/x86/include/asm/irqflags.h
> >> +++ b/arch/x86/include/asm/irqflags.h
> >> @@ -33,7 +33,8 @@ extern inline unsigned long native_save_fl(void)
> >>  	return flags;
> >>  }
> >>  
> >> -static inline void native_restore_fl(unsigned long flags)
> >> +extern inline void native_restore_fl(unsigned long flags);
> >> +extern inline void native_restore_fl(unsigned long flags)
> > 
> > This looks odd to me, but my coffee hasn't kicked in yet this morning.
> > Why do you need both lines here?  Shouldn't the actual function be
> > sufficient?  If not, a comment explaining this would be nice.
> 
> Look just some lines further up:
> 
> /* Declaration required for gcc < 4.9 to prevent
> -Werror=missing-prototypes */
> extern inline unsigned long native_save_fl(void);
> extern inline unsigned long native_save_fl(void)

Ugh, my fault, I'll go shut up now...

stupid gcc...

Re: [PATCH] x86/irqflags: mark native_restore_fl extern inline

[Nick Desaulniers]

On Tue, Aug 28, 2018 at 5:43 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Tue, Aug 28, 2018 at 08:02:37AM +0200, Juergen Gross wrote:
> > On 28/08/18 07:13, Greg Kroah-Hartman wrote:
> > > On Mon, Aug 27, 2018 at 02:40:09PM -0700, Nick Desaulniers wrote:
> > >> Fixes commit 208cbb325589 ("x86/irqflags: Provide a declaration for
> > >> native_save_fl")
> > >>
> > >> This should have been marked extern inline in order to pick up the out
> > >> of line definition in arch/x86/kernel/irqflags.S.
> > >>
> > >> Cc: stable@vger.kernel.org # 4.18, 4.14, 4.9, 4.4
> > >> Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
> > >> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> > >> ---
> > >>  arch/x86/include/asm/irqflags.h | 3 ++-
> > >>  1 file changed, 2 insertions(+), 1 deletion(-)
> > >>
> > >> diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
> > >> index c14f2a74b2be..15450a675031 100644
> > >> --- a/arch/x86/include/asm/irqflags.h
> > >> +++ b/arch/x86/include/asm/irqflags.h
> > >> @@ -33,7 +33,8 @@ extern inline unsigned long native_save_fl(void)
> > >>    return flags;
> > >>  }
> > >>
> > >> -static inline void native_restore_fl(unsigned long flags)
> > >> +extern inline void native_restore_fl(unsigned long flags);
> > >> +extern inline void native_restore_fl(unsigned long flags)
> > >
> > > This looks odd to me, but my coffee hasn't kicked in yet this morning.
> > > Why do you need both lines here?  Shouldn't the actual function be
> > > sufficient?  If not, a comment explaining this would be nice.

That's a valid concern.  I did hesitate while writing the commit
message whether to describe that part or not.  The reason to include
the seemingly-additional-declaration was to prevent another case of
commit 208cbb325589 ("x86/irqflags: Provide a declaration for
native_save_fl").  It doesn't hurt to provide more info in the commit
message, so next time I'll prefer to explain more in my commit
messages than less.

Thanks Juergen and Greg for reviewing the patch.

-- 
Thanks,
~Nick Desaulniers

[tip:x86/urgent] x86/irqflags: Mark native_restore_fl extern inline

[tip-bot for Nick Desaulniers]

Commit-ID:  1f59a4581b5ecfe9b4f049a7a2cf904d8352842d
Gitweb:     https://git.kernel.org/tip/1f59a4581b5ecfe9b4f049a7a2cf904d8352842d
Author:     Nick Desaulniers <ndesaulniers@google.com>
AuthorDate: Mon, 27 Aug 2018 14:40:09 -0700
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 30 Aug 2018 11:37:09 +0200

x86/irqflags: Mark native_restore_fl extern inline

This should have been marked extern inline in order to pick up the out
of line definition in arch/x86/kernel/irqflags.S.

Fixes: 208cbb325589 ("x86/irqflags: Provide a declaration for native_save_fl")
Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180827214011.55428-1-ndesaulniers@google.com

---
 arch/x86/include/asm/irqflags.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index c14f2a74b2be..15450a675031 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -33,7 +33,8 @@ extern inline unsigned long native_save_fl(void)
 	return flags;
 }
 
-static inline void native_restore_fl(unsigned long flags)
+extern inline void native_restore_fl(unsigned long flags);
+extern inline void native_restore_fl(unsigned long flags)
 {
 	asm volatile("push %0 ; popf"
 		     : /* no output */