Bug 214 - ISAMUX/NS Standard writeup needed
Summary: ISAMUX/NS Standard writeup needed
Status: IN_PROGRESS
Alias: None
Product: Libre-SOC's first SoC
Classification: Unclassified
Component: Specification (show other bugs)
Version: unspecified
Hardware: Other Linux
: --- enhancement
Assignee: Alain D D Williams
URL:
Depends on:
Blocks: 174
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Reported: 2020-03-09 22:14 GMT by Luke Kenneth Casson Leighton
Modified: 2020-12-02 15:05 GMT (History)
2 users (show)

See Also:
NLnet milestone: NLNet.2019.10.Standards
total budget (EUR) for completion of task and all subtasks: 2500
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Description Luke Kenneth Casson Leighton 2020-03-09 22:14:58 GMT
The ISAMUX/NS Standard, applied to POWER ISA, needs to be written up in a form suitable for proposal to the OpenPOWER Foundation.  Followthrough to adoption included.

See informal writeup:
https://libre-riscv.org/isa_conflict_resolution/isamux_isans/
Comment 2 Alain D D Williams 2020-08-18 20:10:25 BST
This has, at long last, been started.
Comment 3 Luke Kenneth Casson Leighton 2020-08-22 17:57:45 BST
alain just sone notes from our conversation: there are 2 aspects.

1. PCR binary encoded range (6 bits) to be proposed, and for libresoc to request "0b000001"

this places the CPU into "libresoc compatibility mode" 

2. reservation and use of some MSR bits.  this for *internal* LibreSOC usage.

the OpenPOWER Foundation needs to be requested officially to reserve (1) as part of the spec.

the OpenPOWER Foundation needs to be *notified* of our intent (2) but given that it is ONLY enabled in PCR-sets-LibreSOC-Compatible-mode it is NOT necessary to request authorisation for it, NOR to request that it be included in the OpenPOWER spec.

however they still need to review (2) to make sure that it does not interfere with future plans for MSR.