[GIT PULL] prefetch support for 3.13

[Stephen Warren]

On 10/30/2013 09:25 AM, Russell King - ARM Linux wrote:
> On Wed, Oct 30, 2013 at 08:24:35AM -0700, Paul Walmsley wrote:
>> Hi Will et al.,
>>
>> On 10/09/2013 10:13 AM, Will Deacon wrote:
>>> Hi Russell,
>>>
>>> Please pull the following patches for 3.13. They add support for the pldw
>>> instruction (prefetch with intent to modify) in ARMv7 SMP cores, which is
>>> then used to gain a measurable performance boost for particular atomic
>>> sequences.
>>
>> Looks like the pldw changes require binutils >= 2.21.  Might be worth  
>> considering a patch to update Documentation/Changes?
> 
> Not really - because that says "for all architectures the minimum
> requirement is now 2.21 or later" and that's certainly not the case.

By "that", do you mean the text Paul wrote? I don't think he was
suggesting that as a patch.

> It's only ARMv7 which requires this.

Wouldn't it make sense to document this still? Can't we just put a list
of minimum requirements into Documentation/Changes based on architecure,
e.g.:

o  binutils               2.21                    # ld -v (ARMv7)
o  binutils               2.12                    # ld -v (other)

At the very least, the current documentation is wrong, because there are
clearly cases where binutils-2.12 isn't sufficient.