Re: [PATCH 07/25] x86, pkeys: new page fault error code bit: PF_PK

From	Dave Hansen <dave@sr71.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH 07/25] x86, pkeys: new page fault error code bit: PF_PK
Date	2015-10-01 19:20 +0200
Message-ID	<qePGq-2Bk-19@gated-at.bofh.it> (permalink)
References	<qdM7T-59-3@gated-at.bofh.it> <qdMhB-gH-41@gated-at.bofh.it> <qeKGK-383-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 10/01/2015 04:54 AM, Thomas Gleixner wrote:
> On Mon, 28 Sep 2015, Dave Hansen wrote:
>> >  
>> >  /*
>> > @@ -916,7 +918,10 @@ static int spurious_fault_check(unsigned
>> >  
>> >  	if ((error_code & PF_INSTR) && !pte_exec(*pte))
>> >  		return 0;
>> > -
>> > +	/*
>> > +	 * Note: We do not do lazy flushing on protection key
>> > +	 * changes, so no spurious fault will ever set PF_PK.
>> > +	 */
> It might be a bit more clear to have:
> 
>    	/* Comment .... */
>   	if ((error_code & PF_PK))
>   		return 1;
> 
>   	return 1;
> 
> That way the comment is associated to obviously redundant code, but
> it's easier to read, especially if we add some new PF_ thingy after
> that.

Agreed, that's a nicer way to do it.  I'll fix it up.
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Thread

[PATCH 00/25] x86: Memory Protection Keys Dave Hansen <dave@sr71.net> - 2015-09-28 21:30 +0200
  [PATCH 21/25] mm: implement new mprotect_key() system call Dave Hansen <dave@sr71.net> - 2015-09-28 21:30 +0200
    Re: [PATCH 21/25] mm: implement new mprotect_key() system call Michael Ellerman <mpe@ellerman.id.au> - 2015-09-29 08:40 +0200
      Re: [PATCH 21/25] mm: implement new mprotect_key() system call Dave Hansen <dave@sr71.net> - 2015-09-29 16:20 +0200
  [PATCH 07/25] x86, pkeys: new page fault error code bit: PF_PK Dave Hansen <dave@sr71.net> - 2015-09-28 21:30 +0200
    Re: [PATCH 07/25] x86, pkeys: new page fault error code bit: PF_PK Thomas Gleixner <tglx@linutronix.de> - 2015-10-01 14:00 +0200
      Re: [PATCH 07/25] x86, pkeys: new page fault error code bit: PF_PK Dave Hansen <dave@sr71.net> - 2015-10-01 19:20 +0200
  [PATCH 16/25] x86, pkeys: optimize fault handling in access_error() Dave Hansen <dave@sr71.net> - 2015-09-28 21:30 +0200
  [PATCH 13/25] mm: factor out VMA fault permission checking Dave Hansen <dave@sr71.net> - 2015-09-28 21:30 +0200
  [PATCH 08/25] x86, pkeys: store protection in high VMA flags Dave Hansen <dave@sr71.net> - 2015-09-28 21:30 +0200
  [PATCH 06/25] x86, pkeys: PTE bits for storing protection key Dave Hansen <dave@sr71.net> - 2015-09-28 21:30 +0200
  [PATCH 14/25] mm: simplify get_user_pages() PTE bit handling Dave Hansen <dave@sr71.net> - 2015-09-28 21:30 +0200

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