linux-kernel - Re: Folding _PAGE_PWT into _PAGE_PCD (was Re: unify pagetable accessors patch causes double fault II)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <478CEE45.1040006@goop.org>
Date:	Tue, 15 Jan 2008 09:32:53 -0800
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	Andi Kleen <andi@...stfloor.org>
CC:	Ingo Molnar <mingo@...e.hu>, tglx@...utronix.de,
	linux-kernel@...r.kernel.org
Subject: Re: Folding _PAGE_PWT into _PAGE_PCD (was Re: unify pagetable accessors
 patch causes double fault II)

Andi Kleen wrote:
>> BTW, I just noticed that _PAGE_PWT has been folded into _PAGE_PCD.  This 
>> seems like a really bad idea to me, since it breaks the rule that 
>> _PAGE_X == 1 << _PAGE_BIT_X.  I can't think of a specific place where 
>> this would cause problems, but this kind of non-uniformity always ends 
>> up biting someone in the arse.
>>     
>
> Agreed that it's a bad idea.
>
>   
>> I think having a specific _PAGE_NOCACHE which combines these bits is a 
>> better approach.
>>     
>
> CPA series adds that already
>
> +/* Needs special handling for large pages */
> +#define _PAGE_CACHE     (_PAGE_PCD|_PAGE_PWT|_PAGE_PAT)
>   

Good, but isn't the name _PAGE_CACHE misleading?  Or does it mean 
something else in the context of PAT?

    J
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/