Re: [PATCH] [RFC] ARM: vdso: work around gcc-8 warning

From	Arnd Bergmann <arnd@arndb.de>
Newsgroups	linux.kernel
Subject	Re: [PATCH] [RFC] ARM: vdso: work around gcc-8 warning
Date	2017-08-23 16:20 +0200
Message-ID	<uhEFH-1Aq-5@gated-at.bofh.it> (permalink)
References	<uhEw1-1x1-9@gated-at.bofh.it> <uhEw1-1x1-11@gated-at.bofh.it> <uhEFH-1Aq-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed, Aug 23, 2017 at 4:11 PM, Mark Rutland <mark.rutland@arm.com> wrote:
> On Wed, Aug 23, 2017 at 03:07:04PM +0100, Ard Biesheuvel wrote:
>> On 23 August 2017 at 15:05, Arnd Bergmann <arnd@arndb.de> wrote:

>> > diff --git a/arch/arm/include/asm/vdso.h b/arch/arm/include/asm/vdso.h
>> > index d0295f1dd1a3..eff7d3a1d1ce 100644
>> > --- a/arch/arm/include/asm/vdso.h
>> > +++ b/arch/arm/include/asm/vdso.h
>> > @@ -11,7 +11,7 @@ struct mm_struct;
>> >
>> >  void arm_install_vdso(struct mm_struct *mm, unsigned long addr);
>> >
>> > -extern char vdso_start, vdso_end;
>> > +extern int vdso_start, vdso_end;
>> >
>> >  extern unsigned int vdso_total_pages;
>>
>> May I suggest
>>
>> extern char vdso_start[], vdso_end[];

This was my first attempt, but when I ran into a build error I did not
even look further

> FWIW, arm64 does this to solve this problem, since commit:
>
> dbbb08f500d61463 ("arm64, vdso: Define vdso_{start,end} as array")
>
> ... and x86 has done likewise for a while.

Yes, this looks good, I'll send a patch to do the same.

    Arnd

Thread

[PATCH] [RFC] ARM: vdso: work around gcc-8 warning Arnd Bergmann <arnd@arndb.de> - 2017-08-23 16:10 +0200
  Re: [PATCH] [RFC] ARM: vdso: work around gcc-8 warning Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-08-23 16:10 +0200
    Re: [PATCH] [RFC] ARM: vdso: work around gcc-8 warning Mark Rutland <mark.rutland@arm.com> - 2017-08-23 16:20 +0200
      Re: [PATCH] [RFC] ARM: vdso: work around gcc-8 warning Arnd Bergmann <arnd@arndb.de> - 2017-08-23 16:20 +0200
  Re: [PATCH] [RFC] ARM: vdso: work around gcc-8 warning Russell King - ARM Linux <linux@armlinux.org.uk> - 2017-08-24 18:10 +0200

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