esp-idf/components/xtensa/linker.lf

[mapping:xtensa]
archive: libxtensa.a
entries:
    * (noflash_text)            # Default all functions to IRAM
    xt_trax (default)
    xtensa_intr (default)

[mapping:xt_hal]
archive: libxt_hal.a
entries:
    * (noflash_text)