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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>,
	Paul Mackerras <paulus@samba.org>,
	linuxppc-dev <linuxppc-dev@ozlabs.org>
Subject: Re: powerpc/book3s: Fix flush_tlb cpu_spec hook to take a generic argument.
Date: Fri, 03 Oct 2014 18:04:13 +1000	[thread overview]
Message-ID: <1412323453.30859.31.camel@pasglop> (raw)
In-Reply-To: <20141003073622.3F0B8140180@ozlabs.org>

On Fri, 2014-10-03 at 17:36 +1000, Michael Ellerman wrote:
> It seems that the only detail we are abstracting here is that power7 has 128
> TLB sets and power8 has 512. Is that right?

Today ...

> It seems like a lot of code to deal with that one detail.
> 
> I guess the other thing it does is cur_cpu_spec->flush_tlb() is only
> implemented on power7 and power8, ie. not power6. But it seems that the two
> callers can only ever run on power7/power8 anway.
> 
> So couldn't we just do:
>  - add the number of tlb_sets to cpu_spec
>  - use that in flush_tlb()

Provided the form of tlbiel we use remains ... things are different from
embedded for example. I've asked Mahesh to add this hook with the idea
somewhat to migrate existing/older code to use it as well, and on older
chips or embedded the TLB flush is quite different.

Cheers,
Ben.

  reply	other threads:[~2014-10-03  8:04 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-23  3:53 [PATCH] powerpc/book3s: Fix flush_tlb cpu_spec hook to take a generic argument Mahesh J Salgaonkar
2014-10-03  7:36 ` Michael Ellerman
2014-10-03  8:04   ` Benjamin Herrenschmidt [this message]
2014-11-28 22:38 ` Michael Ellerman
2014-12-02  9:01   ` Mahesh Jagannath Salgaonkar
2014-12-04  9:35     ` Michael Ellerman
2014-12-05  4:33       ` Mahesh Jagannath Salgaonkar

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