Thanks for the response.
The value of xTickCount never changes once execution has been halted, either at a breakpoint or by hitting ^C in gdb, regardless of how long renode is allowed to run after the initial halt:
connect with gdb
break with ^C
<see a sensible number, indicating that many ticks happened>
<wait 10 seconds or so, during which time there should have been thousands of simulated ticks>
break with ^C
What’s interesting is that there are ticks to begin with, but then they do not continue to happen after a break/continue.
To the best of my knowledge renode is correctly configured to model the underlying hardware – I guess that the most relevant configuration options for renode, with respect to the timer interrupt, would be for the PLIC and CLINT, and they do match the hardware.
plic: IRQControllers.PlatformLevelInterruptController @ sysbus 0x40000000
[0-3] → cpu@[8-11]
prioritiesEnabled : false
clint: IRQControllers.CoreLevelInterruptor @ sysbus 0x44000000
[0, 1] → cpu@[3, 7]
Here is another data point that I believe is relevant. There is another FreeRTOS port for riscv provided by Microchip (then Microsemi):
The implementation of this port is significantly different from the one that lives in the FreeRTOS tree (portable/GCC/RISC-V) nowadays. In the Microsemi port, the tick timer behavior is implemented mostly using the vendor-provided HAL routines (in riscv_hal.c) rather than in the FreeRTOS port.c/portASM.S files.
I replaced the port in FreeRTOS/Demo/RISC-V_Renode_Emulator_SoftConsole with the port files from the above Microsemi project and was able to break and then continue in renode many times, and the tick continued to behave as expected. To me this indicates that the issue is probably not a problem with the renode configuration. More likely it’s some difference in how the two ports are implemented. But I can’t understand how that would make one of them misbehave after a breakpoint.
I could use the Microsemi port code as a workaround, but I’d like to understand the issue rather than blindly use an old port that I found on a random GH repo. Also, I believe this issue would affect anyone trying to run the FreeRTOS/Demo/RISC-V_Renode_Emulator_SoftConsole demo. I’ve certainly reproduced it on multiple machines, with multiple versions of SoftConsole/gdb/renode.