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From: Kumar Gala <kumar.gala@freescale.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Subject: Re: [PATCH 11/16] powerpc/mm: Add SMP support to no-hash TLB handling
	v3
Date: Mon, 15 Dec 2008 14:57:33 -0600
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On Dec 15, 2008, at 2:46 PM, Benjamin Herrenschmidt wrote:

>>>
>>> Index: linux-work/arch/powerpc/include/asm/mmu.h
>>> ===================================================================
>>> --- linux-work.orig/arch/powerpc/include/asm/mmu.h	2008-12-15
>>> 14:36:20.000000000 +1100
>>> +++ linux-work/arch/powerpc/include/asm/mmu.h	2008-12-15
>>> 14:36:20.000000000 +1100
>>> @@ -15,6 +15,9 @@
>>> #define MMU_FTR_TYPE_FSL_E		ASM_CONST(0x00000010)
>>> #define MMU_FTR_HAS_HIGH_BATS		ASM_CONST(0x00010000)
>>> #define MMU_FTR_BIG_PHYS		ASM_CONST(0x00020000)
>>> +#define MMU_FTR_HAS_TLBIVAX_BCAST	ASM_CONST(0x00040000)
>>> +#define MMU_FTR_HAS_TLBILX_PID		ASM_CONST(0x00080000)
>>
>> Can we make these FTR_USE_ instead of FTR_HAS_.  On e500 we have
>> TLBIVAX_BCAST but dont plan to use it.  I'd prefer not to have to
>> answer questions about that.
>
> Hehehe :-) I can change that easily yes.

Probably good to add something in the commit message about how  
FTR_USE_ implies FTR_HAS_ just so when some comes back through the git  
history the know we thought about it.

>>> +#define MMU_FTR_TLBIVAX_NEED_LOCK	ASM_CONST(0x00100000)
>>
>> Is this really ivax lock or sync lock?
>
> The whole thing. Not totally clear, you have a better name ? Some CPUs
> want a lock on sync and some on ivax, I plan to lock the whole  
> sequence.

MMU_FTR_TLBIVAX_OR_SYNC_NEED_LOCK ?

Its probably a good idea to have a clear definition of what each of  
these flags means in the commit message.

-k