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Debug integration: abstract memory access shall clear tags #1069

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1 change: 1 addition & 0 deletions src/cheri/contributors.adoc
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Expand Up @@ -23,6 +23,7 @@ This RISC-V specification has been contributed to directly or indirectly by:
* Maja Malenko <maja.malenko@codasip.com>
* A. Theodore Markettos <theo.markettos@cl.cam.ac.uk>
* Alfredo Mazzinghi <alfredo.mazzinghi@cl.cam.ac.uk>
* Jan Matyas <jan.matyas@codasip.com>
* Dave McEwan <dave.mcewan@codasip.com>
* David McKay <david.mckay@codasip.com>
* Jamie Melling <jamie.melling@codasip.com>
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30 changes: 27 additions & 3 deletions src/cheri/debug-integration.adoc
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Expand Up @@ -30,9 +30,9 @@ relaxed if some other means of accessing capabilities in integer registers,
such as an extension of the Access Register abstract command, is added.

The following sequences demonstrate how a debugger can read and write a capability
in `{creg}1` if `MXLEN` is 64, `hartinfo.dataaccess` is 0, `hartinfo.dataaddr` is
0xBF0, `hartinfo.datasize` is 1, `hartinfo.nscratch` is at least 1, `dmstatus.impebreak` is 0,
and `abstractcs.progbufsize` is 5:
in `{creg}1` using the program buffer if `MXLEN` is 64, `hartinfo.dataaccess` is 0,
`hartinfo.dataaddr` is 0xBF0, `hartinfo.datasize` is 1, `hartinfo.nscratch` is at least 1,
`dmstatus.impebreak` is 0, and `abstractcs.progbufsize` is 5:

[source,subs=attributes+]
----
Expand Down Expand Up @@ -85,6 +85,30 @@ no way to discover the former property.
setting `transfer` to 1 and `write` to 0).
====

==== Abstract Commands

This section describes the behavior of _Abstract Commands_, specified by the
_RISC-V Debug Specification_ in section 3.7, on harts that implement
{cheri_base_ext_name}.

===== Access Register Abstract Command

TODO

// This section should be created per the outcome of:
// https://github.com/riscv/riscv-cheri/issues/1039

===== Access Memory Abstract Command

If the debug module implements _Access Memory Abstract Command_, then any write
to memory through this abstract command shall clear the capability tag (or tags)
associated with that memory location.

[NOTE]
====
Misaligned write may clear at most two capability tags.
====

==== Debug Mode

When executing code due to an abstract command, the hart stays in debug mode
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