The linker defines some symbols that are reserved by ARM®, and that you can access if required.
Symbols that contain the character sequence
$$, and all other external names containing the sequence
$$, are names reserved by ARM.
You can import these symbolic addresses and use them as relocatable addresses by your
assembly language programs, or refer to them as
from your C or C++ source code.
Be aware that linker-defined symbols are only generated when your code references them.