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From: "Aneesh Kumar K.V" <aneesh.kumar@linux•vnet.ibm.com>
To: Phileas Fogg <phileas-fogg@mail•ru>,
	Geoff Levand <geoff@infradead•org>,
	linuxppc-dev@lists•ozlabs.org
Subject: Re: Re[3]: PS3 platform is broken on Linux 3.7.0
Date: Sun, 10 Feb 2013 21:41:37 +0530	[thread overview]
Message-ID: <87k3qg4092.fsf@linux.vnet.ibm.com> (raw)
In-Reply-To: <1360487778.293641922@f350.mail.ru>

Phileas Fogg <phileas-fogg@mail•ru> writes:

>  And another note.
> I took a look at the MMU chapter in the Cell Architecture handbook and in=
deed the first 15 bits in VA are treated as 0 by the hardware.
>
> Quote:
>
> 1. High-order bits above 65 bits in the 80-bit virtual address (VA[0:14])=
 are not implemented. The hardware always
> =C2=A0=C2=A0 treats these bits as `0'. Software must not set these bits t=
o any other value than `0' or the results are undefined in
> =C2=A0=C2=A0 the PPE.
>
>

True, we missed the below part of ISA doc:

ISA doc says

"On implementations that support a virtual address size
of only n bits, n < 78, bits 0:77-n of the AVA field must be
zeros. "

The Cell document I found at=20

https://www-01.ibm.com/chips/techlib/techlib.nsf/techdocs/7A77CCDF14FE70D58=
52575CA0074E8ED/$file/CellBE_Handbook_v1.12_3Apr09_pub.pdf

gives=20

Virtual Address (VA) Size -> 65 bits

So as per ISA, bits 0:12 should be zero, which should make 0:14 of PTE
fields zero for Cell.

I will try to do a patch.=20

Thanks for debugging this.

-aneesh

  reply	other threads:[~2013-02-10 16:11 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-14 12:35 PS3 platform is broken on Linux 3.7.0 Phileas Fogg
2012-12-19 21:53 ` Benjamin Herrenschmidt
2013-01-12  2:12   ` Geoff Levand
2013-01-14 23:37     ` Geoff Levand
2013-02-10  8:59       ` Re[2]: " Phileas Fogg
2013-02-10  9:16         ` Re[3]: " Phileas Fogg
2013-02-10 16:11           ` Aneesh Kumar K.V [this message]
2013-02-11 10:26             ` Aneesh Kumar K.V
2013-02-11 16:57               ` Re[5]: " Phileas Fogg
2013-02-12  1:11               ` Re[3]: " Geoff Levand
2013-02-11 20:56         ` Re[2]: " Geoff Levand
2013-02-10 11:45   ` Phileas Fogg
2013-02-10 12:17     ` Re[3]: " Phileas Fogg
2013-02-10 15:46       ` Aneesh Kumar K.V
2013-02-10 17:51         ` Re[5]: " Phileas Fogg
2013-02-11  3:39           ` Michael Ellerman
2013-02-13  7:32 ` Geoff Levand
2013-02-13 22:37   ` Michael Ellerman

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