Half solved.
The folks at Freescale put "-largeAddrInSdm" in the documentation, but "-largeaddrinsdm" in the compiler code.
So the latter works and the former doesn't.
(Seems like an UpperCase call is missing in the compiler..)
Anyway, now since I have a bunch of strings in the secondary flash, I declare them as unsigned chars of 1 byte.
The 56F8000Ex core doubles the byte addresses (like in move.bp) and this means that all word-addresses beyond 0x8000
become byte-addresses beyond 0x10000 (4 zeros).
This is over the 16 bit maximum displacement of the Small Data Model and the Linker complains that it is too far.
">is too far away for a R_56800E_BYTE16 relocation, which has a range from 0 to
>65535 bytes"
So there is this limitation in using the Secondary Flash for data: you cannot use Byte addressing for objects there.
That is pretty bad, because to put arrays of constant chars in ram is a big waste, and to put them in Program Memory you must name them with an identifier, because the compiler cannot generate program memory addressable string constants (no way I'm aware of...)
Hope this helps whoever wants to wrestle with these things.
