The coverage-plugin is a C++ project using the Model Trace Interface Plugin Development Kit (MTIPDK) in order to create a trace plugin, which is a special shared library. The trace plugins can be loaded into Arm Fast Models to produce execution trace data for doing code coverage measurement.
$ cd coverage-plugin $ make PVLIB_HOME=</path/to/model_library>
You need to add two options to your model command-line:
--plugin /path/to/coverage_trace.so -C TRACE.coverage_trace.trace-file-prefix="/path/to/TRACE-PREFIX"
You can then run your FVP model. The traces will be created at the end of the simulation*.
BEWARE: Traces aren't numbered and will be overwritten if you do two successive runs. Aggregating results will require moving traces to a separate place or changing the prefix between runs. This is the responsibility of the plugin user.
*NOTE: The plugin captures the traces in memory and on the termination of the simulation it writes the data to a file. If user terminates the simulation forcefully with a Ctrl+C the trace files are not generated. Traces can be saved by interacting with the plugin itself. More info can be found in the Interacting with the plugin chapter .
The coverage tool support only tracing specific exception levels. This is useful when trying to trace a small part of a bigger system. This is for example used to measure the code coverage of the OP-TEE secure OS. Where the trace is only being recorded while being inside S-EL1. The exception level can be specified by passing the TRACE.coverage_trace.trace-mode option. The passed value is a 32b bit field.
| exception Level | Bit Field |
|---|---|
| None secure modes | |
| EL0t | 0 |
| EL1t | 1 |
| EL1h | 2 |
| EL2t | 3 |
| EL2h | 4 |
| EL3t | 5 |
| EL3h | 6 |
| usr | 7 |
| fiq | 8 |
| irq | 9 |
| svc | 10 |
| mon | 11 |
| abt | 12 |
| hyp | 13 |
| und | 14 |
| sys | 15 |
| Secure modes | |
| EL0t | 16 |
| EL1t | 17 |
| EL1h | 18 |
| EL2t | 19 |
| EL2h | 20 |
| EL3t | 21 |
| EL3h | 22 |
| usr | 23 |
| fiq | 24 |
| irq | 25 |
| svc | 26 |
| mon | 27 |
| abt | 28 |
| hyp | 29 |
| und | 30 |
| sys | 31 |
The trace-mode and the trace-file-prefix can both be changed at run-time. Every time the trace-file-prefix value is changed, the plugin will save the trace result. This can be used to save the result without the need for the simulation to end.
#!/usr/bin/python import iris.debug as debug import iris.iris as iris trace_file_prefix = "" self.model = debug.NetworkModel("localhost",9000) self.trace_component = None components = self.model.get_targets() for component in components: if "coverage_trace" in component.instName: self.trace_component = component if not self.trace_component: fail_msg("Trace component not found") else: # Save the trace results self.trace_component.parameters['trace-file-prefix'] = trace_file_prefix