I accessed unallowed memory range (0x1FFEF654, which is out of memory range)
But I couldnt' the MPU Error Information in S32K146 MCU by checking Trace32 Debugger.
So I checked Arm CM4 Registers and then the checked Information is like below these informations.
// S32K146 MCU's MPU
All of SPER# is 0 (No Error Occurred)
EADDR is 0
But the MPU in MCU is enabled.
/// ARM CM4 Reg Value //
Memory Protection Unit
MPU_TYPE : 00000000 /IREGION: 0 /DREGION:0 /SEPERATE: Not Supported
MPU_CTRL: 00000000 /PRIVDEFENA: Disabled HFMINEA: MPU Disabled /ENABLE: Disabled
MPU_RNR: 00000000 /REGION:00
=> So I checked MPU in Arm core is disabled.
But the other register values are below things.
MMFAR : 1FFEF654 (out of memory range in S32K146)
MMFSR is Initialized Values (Not Valid, Not Active, Not Occurred)
BFSR
- BFARVALID: Valid / PRECISERR: Occurred
BFAR : 1FFEF654 (out of memory range in S32K146)
HFSR
- Forced : Occurred / DEBEUGEV, VECTTBL : Not Occurred
=> So I think Bus Fault Handler makes MemManageFault Escalate to Hard Fault.
But I can't understand how MPU in Arm Core is not activated makes MemManage Fault?
If XN Region accessed makes this situation, I think IACCVIOL in MMFSR Should be Occurred
because It is not clear by another exception handler like MMARVALID in MMFSR.
Would you explain this situations and would you offer the algorithm of how accessing to
out of memory range leads to hard fault handler?
Thank you for your support.
