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Re: [tip:x86/urgent] x86/io: Mark target address as output in 'insb()' asm

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* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Wed, Jul 12, 2017 at 6:10 AM, tip-bot for Arnd Bergmann
> <tipbot@zytor.com> wrote:
> >
> > Apparently the assember constraints are slightly off here, as marking the
> > 'addr' argument as a memory output seems appropriate here and gets rid
> > of the warning. For consistency I'm also adding it as input for outsb().
> 
> The new constraints look very questionable to me.

Ok, I've removed the commit.

> The real fix is probably to just mark them as "clobbers memory" (ie
> just add "memory" to the clobber list).
> 
> If you want to be fancy, you can try to do what <asm/uaccess.h> does,
> which is a disgusting hack, but has traditionally worked;
> 
>   struct __large_struct { unsigned long buf[100]; };
>   #define __m(x) (*(struct __large_struct __user *)(x))
> 
> and then use your approach with "m" and "=m".

Arnd, could you please try Linus's suggestions?

Thanks,

	Ingo

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[RFC 1/2] x86: mark target address as output in 'insb' asm Arnd Bergmann <arnd@arndb.de> - 2017-07-10 16:50 +0200
  [RFC 2/2] wl3501_cs: reduce stack size for KASAN Arnd Bergmann <arnd@arndb.de> - 2017-07-10 16:50 +0200
  [tip:x86/urgent] x86/io: Mark target address as output in 'insb()'  asm tip-bot for Arnd Bergmann <tipbot@zytor.com> - 2017-07-12 15:20 +0200
    Re: [tip:x86/urgent] x86/io: Mark target address as output in  'insb()' asm Linus Torvalds <torvalds@linux-foundation.org> - 2017-07-12 19:00 +0200
      Re: [tip:x86/urgent] x86/io: Mark target address as output in  'insb()' asm Ingo Molnar <mingo@kernel.org> - 2017-07-12 21:30 +0200
      Re: [tip:x86/urgent] x86/io: Mark target address as output in  'insb()' asm Arnd Bergmann <arnd@arndb.de> - 2017-07-12 23:50 +0200
        Re: [tip:x86/urgent] x86/io: Mark target address as output in  'insb()' asm Linus Torvalds <torvalds@linux-foundation.org> - 2017-07-13 00:50 +0200

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