S32K312 After integrating SCST, the SCST test fails the first run and passes all subsequent times

[Yongxingjia]

I am using S32K312 chip to integrate SCST, the compiler used is GHS 20220104, the compilation, link attributes, and MPU are all configured according to the manual, and the macro configuration in m7_scst_configuration.h is as follows:

S32K312 After integrating SCST, the SCST m7_scst_exception_usage_fault_test test fails the first run and passes all subsequent times

The debugging situation is as follows：

The first run m7_scst_execute_core_tests(0, 0); The result is wrong

2nd run m7_scst_execute_core_tests (0, 0); The result is correct

The first run m7_scst_execute_core_tests(0, 49); The result is wrong

2nd run m7_scst_execute_core_tests (0, 49); The result is correct

What are the possible reasons for this happening and how to fix it？

Thank you！

[martinkaspar-r3 · Accepted solution]

Hello,
It looks like the global variables, which are placed in m7_scst_test_shell_data section, are not properly initialized.
Especially m7_scst_fault_inject_test_index variable shall be initialized to 0xFFFFFFFF.

If this variable is initialized to 0 before m7_scst_execute_core_tests function is called, then fault is injected to test with index 0 -> m7_scst_exception_usage_fault_test, and wrong signature is returned. Variable m7_scst_fault_inject_test_index is then reinitialized to 0xFFFFFFFF, so other runs returns the correct signature.

[Yongxingjia]

That's really the reason, thank you very much!