HelenOS sources

ESR_IDA_IDFSC_TF0  138 boot/arch/arm64/include/arch/regutils.h #define ESR_IDA_IDFSC_TF0  0x4
ESR_IDA_IDFSC_TF0  138 kernel/arch/arm64/include/arch/regutils.h #define ESR_IDA_IDFSC_TF0  0x4
ESR_IDA_IDFSC_TF0  138 uspace/lib/c/arch/arm64/include/libarch/regutils.h #define ESR_IDA_IDFSC_TF0  0x4

HelenOS homepage, sources at GitHub