Skip to content

Ian feedback issue3 #4

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
bcstrongx wants to merge 2 commits into
base: main
Choose a base branch
from
Open

Ian feedback issue3 #4

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
9a9db6d
fix typos, and add introduction to strc chapter
bcstrongx Nov 5, 2025
6b612ce
update f0s_width value to support all modes
bcstrongx Nov 5, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
14 changes: 10 additions & 4 deletions src/smstrc.adoc
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,11 @@
== Self-hosted Trace ISA Extension (Smstrce1p0/Ssstrce1p0 and Smstrcn1p0/Ssstrcn1p0)

The Smstrce1p0/Ssstrce1p0 and Smstrcn1p0/Ssstrcn1p0 extensions introduce an ISA interface to the existing E-trace and N-trace (non-ISA) trace extensions, respectively. The intent is to simplify in-target software use of trace, also known as self-hosted trace, for debugging, performance analysis, fuzzing, code coverage, and other applications.

The Smstrc*/Ssstrc* extensions depend upon Ssamb, as an asynchronous memory buffer is used as the trace sink.

"Strc" refers to self-hosted trace, "e" vs "n" refer to E-trace vs N-trace, and "1p0" refers to version 1.0 of each trace extension. The machine-level extensions, Smstrc*, encompass all newly added registers and behavior modifications for a hart across all privilege levels. The corresponding supervisor-level extensions, Ssstrc*, are essentially identical to Smstrc*, except that they exclude machine-level registers and behaviors not intended to be directly accessible at the supervisor level.

[[strccsrs]]
=== CSRs

Expand Down Expand Up @@ -96,11 +102,11 @@ The `sstrcctl` register provides supervisor mode access to a subset of `mstrcctl

==== Supervisor Self-hosted Trace Control and Status (`sstrcambcs`)

The `sstrcambcs` register is the Self-hosted trace instatiation of the `sambcs` register defined by the Ssamb extension, see <<ssamb>>. See <<strcmem>> for Self-hosted trace memory buffer details.
The `sstrcambcs` register is the Self-hosted trace instantiation of the `sambcs` register defined by the Ssamb extension, see <<ssamb>>. See <<strcmem>> for Self-hosted trace memory buffer details.

==== Supervisor Self-hosted Trace AMB Address (`sstrcambaddr`)

The `sstrcambaddr` register is the Self-hosted trace instatiation of the `sambaddr` register defined in the Ssamb specification, see <<ssamb>>. See <<strcmem>> for Self-hosted trace Memory Buffer details.
The `sstrcambaddr` register is the Self-hosted trace instantiation of the `sambaddr` register defined in the Ssamb specification, see <<ssamb>>. See <<strcmem>> for Self-hosted trace Memory Buffer details.

==== Supervisor Context Register (`scontext`)

Expand Down Expand Up @@ -235,10 +241,10 @@ indicates that there is no jump target cache implemented.
|_ctype_width_p_ | 2 (precise) | Width of the *ctype* bus.
|_context_width_p_ | 64 bits | Width of *context* bus.
|_time_width_p_ | Implementation-defined | Width of *time* bus
|_ecause_width_p_ | 7 (Interrupt bit + 0..63 cause values) | Width of *exception cause* bus
|_ecause_width_p_ | 6 (0..63 cause values) | Width of *exception cause* bus
|_ecause_choice_p_ | Any | Number of bits of exception cause to match using
multiple choice
|_f0s_width_p_ | 1, or 2 if want room for growth? | Width of the *subformat* field in format 0 _te_inst_ packets.
|_f0s_width_p_ | 2 | Width of the *subformat* field in format 0 _te_inst_ packets.
|_filter_context_p_ | Any | Filtering on context supported when 1
|_filter_time_p_ | Any | Filtering on time supported when 1
|_filter_excint_p_ | Any | Filtering on exception cause or interrupt
Expand Down