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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: Paul Mackerras via Linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
	linuxppc-dev@lists.ozlabs.org
Cc: Michael Ellerman <mpe@ellerman.id.au>, Paul Mackerras <paulus@samba.org>
Subject: Re: [RFC PATCH 2/9] powerpc/mm/book3s-64: Free up 7 high-order bits in the Linux PTE
Date: Sat, 20 Feb 2016 21:46:19 +0530	[thread overview]
Message-ID: <871t878ii4.fsf@linux.vnet.ibm.com> (raw)
In-Reply-To: <1455948760-24710-3-git-send-email-paulus@samba.org>

Paul Mackerras <paulus@samba.org> writes:

> This frees up bits 57-63 in the Linux PTE on 64-bit Book 3S machines.
> In the 4k page case, this is done just by reducing the size of the
> RPN field to 39 bits, giving 51-bit real addresses.  In the 64k page
> case, we had 10 unused bits in the middle of the PTE, so this moves
> the RPN field down 10 bits to make use of those unused bits.  This
> means the RPN field is now 3 bits larger at 37 bits, giving 53-bit
> real addresses in the normal case, or 49-bit real addresses for the
> special 4k PFN case.


Is it ok to have different real address bits between 4k and 64k linux
config ?

-aneesh

  reply	other threads:[~2016-02-20 16:16 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-20  6:12 [RFC PATCH 0/9] powerpc/mm: Restructure Linux PTE on Book3S/64 to radix format Paul Mackerras
2016-02-20  6:12 ` [RFC PATCH 1/9] powerpc/mm/book3s-64: Clean up some obsolete or misleading comments Paul Mackerras
2016-02-20  6:12 ` [RFC PATCH 2/9] powerpc/mm/book3s-64: Free up 7 high-order bits in the Linux PTE Paul Mackerras
2016-02-20 16:16   ` Aneesh Kumar K.V [this message]
2016-02-21 22:43     ` Paul Mackerras
2016-02-20  6:12 ` [RFC PATCH 3/9] powerpc/mm/64: Use physical addresses in upper page table tree levels Paul Mackerras
2016-02-20 16:35   ` Aneesh Kumar K.V
2016-02-21 22:45     ` Paul Mackerras
2016-02-20  6:12 ` [RFC PATCH 4/9] powerpc/mm/book3s-64: Move _PAGE_PRESENT to the most significant bit Paul Mackerras
2016-02-20  8:33   ` kbuild test robot
2016-02-20 16:41   ` Aneesh Kumar K.V
2016-02-21 22:40     ` Paul Mackerras
2016-02-20  6:12 ` [RFC PATCH 5/9] powerpc/mm/book3s-64: Move _PAGE_PTE to 2nd " Paul Mackerras
2016-02-20  6:12 ` [RFC PATCH 6/9] powerpc/mm/book3s-64: Move HPTE-related bits in PTE to upper end Paul Mackerras
2016-02-20  6:12 ` [RFC PATCH 7/9] powerpc/mm/book3s-64: Shuffle read, write, execute and user bits in PTE Paul Mackerras
2016-02-21  7:30   ` Aneesh Kumar K.V
2016-02-21 22:36     ` Paul Mackerras
2016-02-22  0:27       ` Michael Ellerman
2016-02-20  6:12 ` [RFC PATCH 8/9] powerpc/mm/book3s-64: Move software-used " Paul Mackerras
2016-02-20  6:12 ` [RFC PATCH 9/9] powerpc/mm/book3s-64: Expand the real page number field of the Linux PTE Paul Mackerras
2016-02-20 14:40 ` [RFC PATCH 0/9] powerpc/mm: Restructure Linux PTE on Book3S/64 to radix format Aneesh Kumar K.V
2016-02-20 15:32   ` Aneesh Kumar K.V
2016-02-21  7:41   ` Aneesh Kumar K.V
2016-02-21 22:31     ` Paul Mackerras
2016-02-22  0:30   ` Michael Ellerman

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