tests/ztest/error_hook failed on ARC boards

[IRISZZW]

Describe the bug
tests/ztest/error_hook failed on ARC boards

To Reproduce
Steps to reproduce the behavior:

1. west build -b nsim_em -d build tests/ztest/error_hook
2. west flash
3. See error

Logs and console output

*** Booting Zephyr OS build zephyr-v2.4.0-3232-gf0145f9f3e37  ***
Running test suite error_hook_tests
===================================================================
START - test_catch_assert_fail
ASSERTION FAIL [a != ((void *)0)] @ WEST_TOPDIR/zephyr/tests/ztest/error_hook/src/main.c:41
        parameter a should not be NULL!
Caught assert failed
Assert error expected as part of test case.
 PASS - test_catch_assert_fail
===================================================================
START - test_catch_fatal_error
case type is 0
b is 11588
 FAIL - test_catch_fatal_error
===================================================================
START - test_catch_assert_in_isr
ASSERTION FAIL [a != ((void *)0)] @ WEST_TOPDIR/zephyr/tests/ztest/error_hook/src/main.c:41
        parameter a should not be NULL!
Caught assert failed
Assert error expected as part of test case.
 PASS - test_catch_assert_in_isr
===================================================================
START - test_catch_z_oops
E: ***** Exception vector: 0x6, cause code: 0x1, parameter 0x4
E: Address 0x80000af4
E: EV_ProtV
E: Memory read protection violation (MPU)
E:  r0: 0x80000aec  r1: 0x00000000  r2: 0x00000000  r3: 0x00000000
E:  r4: 0x00000000  r5: 0x00000000  r6: 0x0000011d  r7: 0x00000000
E:  r8: 0x00000000  r9: 0x00000000 r10: 0x00000000 r11: 0x00000000
E: r12: 0x000037c0 r13: 0x8000003c  pc: 0x00000304
E:  blink: 0x000002f4 status32: 0x80184086
E: lp_end: 0x00000000 lp_start: 0x00000000 lp_count: 0x00000000
E: >>> ZEPHYR FATAL ERROR 0: CPU exception on CPU 0
E: Current thread: 0x800008e4 (unknown)
Caught system error -- reason 0 1
Fatal error expected as part of test case.
 PASS - test_catch_z_oops
===================================================================
Test suite error_hook_tests failed.
===================================================================
PROJECT EXECUTION FAILED

Environment (please complete the following information):

• OS: (Linux)
• Toolchain (Zephyr SDK)
• zephyr-v2.4.0-3232-gf0145f9f3e37

[evgeniy-paltsev]

This is new test and it fails due to the specifics of ARC/nSIM.

It fails on sub-test which checks that userspace task will be terminated on null-pointer access. On nSIM boards we don't have memory in 0x0 location. And, as I understand, we cover with MPU only the memory which is declared (CCMs for UP nSIM boards). IOW, the 0x0 address isn't protected by MPU.

However the nSIM simulates full address space of memory, so all accesses outside of CCMs are valid and access to 0x0 address doesn't generate any exception.

Previously we couldn't disable this 'feature', we should check if it is possible with latest nSIM.