Re: [PATCH, ARM, 0/7] Add support for ARMv8-M

["Richard Earnshaw (lists)" <Richard dot Earnshaw at arm dot com>]

On 17/12/15 11:37, Ramana Radhakrishnan wrote:
> On Thu, Dec 17, 2015 at 2:11 AM, Thomas Preud'homme
> <thomas.preudhomme@foss.arm.com> wrote:
>> Hi,
>>
>> I'll be posting a patch series intended for the master branch whose aim is to add support for ARMv8-M. As such, it consists mostly of changes to GAS. This patch series does not include changes to support the security extensions beyond assembling related instructions. This will be posted as a separate patch series.
> 
> I haven't reviewed this yet but I don't think this patch set should go
> into the 2.26 branch yet.
> 

I think it's too risky to even consider for the 2.26 branch.  Period.

R.

> Ramana
> 
>>
>>
>> === Quick overview of ARMv8-M ===
>>
>> ARMv8-M has two profiles[1]: Baseline and Mainline.  In terms of features they can be defined as:
>>
>> ARMv8-M Baseline (armv8-m.base):
>>  * All ARMv6-M features
>>  * 16-bit immediate moves
>>  * Wide Branch
>>  * Compare & branch if (not) zero
>>  * Integer divide
>>  * Load/store exclusives
>>  * Atomic Load/stores
>>  * Security extensions
>>
>> ARMv8-M Mainline (armv8-m.main):
>>  * All ARMv7-M features
>>  * Atomic load/stores
>>  * Security extensions.
>>
>> ARMv8-M Mainline with DSP extension (armv8-m.main+dsp):
>>  * ARMv8-M Mainline
>>  * Those instructions added to ARMv7E-M on top of ARMv7-M.
>>
>> Note that although certain architectural features of the security extensions are optional for cores implementing ARMv8-M, some of the new instructions are always available in the architecture.
>>
>> Note also that only the instructions from security extensions are new instructions, all other instructions have previously been available in other ARM Architecture profiles.
>>
>> [1] http://www.arm.com/products/processors/instruction-set-architectures/armv8-m-architecture.php
>>