id = 1772
title = "MPS2 AN521 has the wrong number of MPU region defined"
state = "closed"
created_at = "2023-07-18T21:11:31.996Z"
closed_at = "2023-08-31T16:14:26.140Z"
labels = ["kind::Bug", "target: arm", "workflow::Patch available"]
url = "https://gitlab.com/qemu-project/qemu/-/issues/1772"
host-os = "any"
host-arch = "any"
qemu-version = "7.0.0"
guest-os = "Zephyr"
guest-arch = "Arm"
description = """The AN521 is integrating SSE-200 on the MPS2+ FPGA prototyping board.
The current implementation in qemu behaves as though there are 16MPU regions when it really only has 8, as describes as `MPU_NS` and `MPU_S` core configuration parameters in the SSE-200's [Techincal Reference Manual](https://developer.arm.com/documentation/101104/0200/functional-description/cpu-elements/cortex-m33-configurations?lang=en)."""
reproduce = """1. Prepare your Zephyr dev environment
2. fix `boards/arm/mps2_an521/mps2_an521.dts` to set `arm,num-mpu-regions`  to the appropriate value of 8.
3. build a Zephyr test such as `west build -p -b mps2_an521 -T tests/kernel/interrupt/arch.interrupt` 
4. run `qemu-system-arm -machine mps2-an521 -chardev stdio,id=con,mux=on -serial chardev:con -kernel ./build/zephyr/zephyr.elf`"""
additional = """With matching MPU region number in QEMU and Zephyr's DTS, the application shows the test suite's progress & outcome.
If there's a mismatch, the application will enter a fault and not display the expected traces."""