[PATCH V2] powerpc/TM: Disable/Enable TM looking at the ibm, pa-features device tree entry

Aneesh Kumar K.V aneesh.kumar at linux.vnet.ibm.com
Thu Nov 13 17:19:41 AEDT 2014


Michael Ellerman <mpe at ellerman.id.au> writes:

> On Wed, 2014-11-12 at 11:09 +0530, Aneesh Kumar K.V wrote:
>> Michael Neuling <mikey at neuling.org> writes:
>> 
>> > On Sun, 2014-11-02 at 20:02 +0530, Aneesh Kumar K.V wrote:
>> >> Runtime disable transactional memory feature looking at pa-features
>> >> device tree entry. We need to do this so that we can run a kernel
>> >> built with TM config in PR mode. 
>> >
>> > I'm happy to turn this off but why do we need to do this in PR mode?
>> > Can you explain this in the commit message.
>> 
>> Hmm, that commit message needs an update. I initially did the patch for
>> P8 PR support and wanted a mechanism to disable TM. Alex added basic TM
>> support for PR mode after that. So we can drop the PR part of the
>> commit message.
>> 
>> Michael Ellerman,
>> 
>> Let me know if you want me to send an updated version with the those
>> part of the commit message dropped
>
> How about:
>
>   powerpc: Disable CPU_FTR_TM if TM is disabled by firmware
>   
>   Firmware is allowed to communicate to us via the "ibm,pa-features" property
>   that TM (Transactional Memory) support is disabled.
>   
>   Currently this doesn't happen on any platform we're aware of, but we should
>   honor it anyway.
>

Looks good.

-aneesh



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