[RFC] Private TBF TLV tag entry

[rajivr]

1. Corrected typo 16 byte specifier to 16 bit specifier

2. I would like to propose that we consider making TLV entries that have highest bit of the 16-bit tag specifier set for private use similar to how we do for driver_num Motivating reasons are -

   • This allows us to experiment with different process loading models
   • Private TLV entries can be used for adding vendor specific metadata such as cryptographic signatures

[jrvanwhy]

I think this should be documented under the "TLV Elements" heading. One possibility is line 195 (the Type bullet), another is in the first paragraph of the "TLV Types" heading (line 203).

[bradjc]

👍 Seems like a useful parallel to the syscall driver numbering convention.

But we should capture this in the /docs as well.

[rajivr]

Thanks for the feedback. I've added comments under section TLV Types.

Please review.

[jrvanwhy]

"standard" is not defined here. The closest sentence to a definition ("A standard set of element types are standardized") needs a rewrite. This makes this section somewhat vague.

How about:

TBF may contain arbitrary element types. To avoid type ID collisions between elements defined by the Tock project and elements defined out-of-tree, the ID space is partitioned into two segments. Type IDs defined by the Tock project will have their high bit (bit 15) unset, and type IDs defined out-of-tree should have their high bit set.

[rajivr]

Thanks for the suggestion. I've applied it. Please review.