HelenOS sources

ESR_IDA_IDFSC_TF2  142 boot/arch/arm64/include/arch/regutils.h #define ESR_IDA_IDFSC_TF2  0x6
ESR_IDA_IDFSC_TF2  142 kernel/arch/arm64/include/arch/regutils.h #define ESR_IDA_IDFSC_TF2  0x6
ESR_IDA_IDFSC_TF2  142 uspace/lib/c/arch/arm64/include/libarch/regutils.h #define ESR_IDA_IDFSC_TF2  0x6

HelenOS homepage, sources at GitHub