ARM tunings was Re: [PATCH 3/7] conf/machine/include: Cleanup MIPS tunings to match README

[Mark Hatle <mark.hatle@windriver.com>]

On 4/9/12 4:03 PM, Phil Blundell wrote:
> On Mon, 2012-04-09 at 15:25 -0500, Mark Hatle wrote:
>> And just to be extra clear, I consider it a defect if we can produce a package
>> with the same name for two different tune settings.. (the exception being the
>> hell that is ARM and thumb namings.)
>
> While you might consider that a defect (and it probably is a defensible
> position to do so), it hasn't historically been considered such in OE.
> The PACKAGE_ARCH value has, traditionally, been concerned purely with
> ISA and ABI (i.e. answering the question "can I execute this code?")
> rather than optimisations.
>
> For example, the tune-arm926ejs.inc and tune-xscale.inc files in current
> oe-core both end up setting PACKAGE_ARCH to "armv5tte" (sic).  But those
> are quite different processors and have different tuning requirements,
> so the binaries you get are unlikely to be the same.  If you were to
> take the view that the PACKAGE_ARCH must uniquely identify one set of
> binaries then obviously each of these tunings (and probably all the ARM
> cpu-specific tunings) would need to set PACKAGE_ARCH to some unique
> value.

I do, and thus the hell that is ARM.  I could not currently generate a single 
package feed that work would on a variety of devices (like a traditional 
workstaton/server Linux OS would.)  While this isn't a big issue in the embedded 
space where we should hopefully be aware of the tunings and configuration were 
are using, it is still a problem.  As the systems get larger, the requirement 
for common pages feeds increases, leading to the problem being, well a problem. 
  (ARM is starting to be considered for Carrier Grade systems, many of which 
have very common requirements to traditional server Linux.  A set of established 
binaries and the vendors just want to drop in optimized applications.)

On ARM what we currently have defined is:
(tune) - (package arch)

arm1136jfs - armv6-vfp
arm920t - armv4t
arm926ejs - armv5te
arm9tdmi - armv4t
armv4b - armv4b
armv4tb - armv4tb
armv4 - armv4
armv4t - armv4t
armv5b - armv5b
armv5b-vfp - armv5b-vfp
armv5eb - armv5eb
armv5eb-vfp - armv5eb-vfp
armv5ehfb-vfp - armv5ehfb-vfp
armv5ehf-vfp - armv5ehf-vfp
armv5e-vfp - armv5e-vfp
armv5hfb-vfp - armv5hfb-vfp
armv5hf-vfp - armv5hf-vfp
armv5tb - armv5tb
armv5tb-vfp - armv5b-vfp
armv5teb - armv5teb
armv5teb-vfp - armv5teb-vfp
armv5tehfb-vfp - armv5tehfb-vfp
armv5tehf-vfp - armv5tehf-vfp
armv5te - armv5te
armv5te-vfp - armv5te-vfp
armv5thfb-vfp - armv5hfb-vfp
armv5thf-vfp - armv5hf-vfp
armv5 - armv5
armv5t - armv5t
armv5t-vfp - armv5-vfp
armv5-vfp - armv5-vfp
armv6b - armv6b-vfp
armv6hfb - armv6hfb-vfp
armv6hf - armv6hf-vfp
armv6tb - armv6tb-vfp
armv6thfb - armv6thfb-vfp
armv6thf - armv6thf-vfp
armv6 - armv6-vfp
armv6t - armv6t-vfp
armv7ab-neon - armv7ab-vfp-neon
armv7ab - armv7ab-vfp
armv7ahfb-neon - armv7ahfb-vfp-neon
armv7ahfb - armv7ahfb-vfp
armv7ahf-neon - armv7ahf-vfp-neon
armv7ahf - armv7ahf-vfp
armv7a-neon - armv7a-vfp-neon
armv7atb-neon - armv7ab-vfp-neon
armv7atb - armv7ab-vfp
armv7athfb - armv7ahfb-vfp
armv7athf-neon - armv7ahf-vfp-neon
armv7athf - armv7ahf-vfp
armv7a - armv7a-vfp
armv7at-neon - armv7a-vfp-neon
armv7at - armv7a-vfp
cortexa8hf-neon - armv7ahf-vfp-neon
cortexa8hf - armv7ahf-vfp
cortexa8-neon - armv7a-vfp-neon
cortexa8thf - armv7ahf-vfp
cortexa8 - armv7a-vfp
cortexa8t - armv7a-vfp
cortexa9hf-neon - armv7ahf-vfp-neon
cortexa9hf - armv7ahf-vfp
cortexa9-neon - armv7a-vfp-neon
cortexa9thf - armv7ahf-vfp
cortexa9 - armv7a-vfp
cortexa9t - armv7a-vfp
cortexm1 - armv7a-vfp
cortexm3 - armv7m-vfp
cortexr4 - armv7r-vfp
ep9312 - ep9312
iwmmxt - iwmmxt
strongarm - armv4

Add in to that one of the tunings -- not indicated by the package arch of thumb 
enabled or not, and its difficult to know exactly what is in a package without 
extracting and examining it.  But I consider this to be a quirk of the ARM 
architecture as implemented in OE.

--Mark

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