Subject: Re: [PATCH -V3 11/11] arch/powerpc: Add 64TB support

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Mon, 23 Jul 2012 15:52:05 +0530

Paul Mackerras <[email-masked]> writes:

> On Mon, Jul 09, 2012 at 06:43:41PM +0530, Aneesh Kumar K.V wrote:
>
>> -#define USER_ESID_BITS		16
>> -#define USER_ESID_BITS_1T	4
>> +#define USER_ESID_BITS		18
>> +#define USER_ESID_BITS_1T	6
>
> You also need to change the proto-VSID generation for kernel addresses
> when you do this.  If you don't you'll end up with some user processes
> using the same VSIDs as we use for the kernel addresses, meaning that
> those processes won't run very well...
>

Can you explain this more. right now we generate vsid as below

vsid_scramble(ea >> SID_SHIFT, 256M) for kernel

vsid_scramble((context << USER_ESID_BITS) | (ea >> SID_SHIFT), 256M);
for user

what changes are you suggesting ?

-aneesh