Yes, it was a kernel parameter for a long time now, from early kernels.
I see what you mean here. I never looked at it that way before. As you found out it describes cache register which is a little technical and not memory size but that's a good guess!I checked commandline kernel parameters, and there are l2cr=0x80000000
My 7455 has 256 kB L2, i.e. 0x40000 and 0x80000000 is 2 GB...
I think you must have done the most research of anyone! It is a good idea to look it up. So, though it is PPC specific, there should be info in the kernel command line documentation but it only says [ PPC ] and nothing else. The most I can find is in an article below. What I do recall is it being set to 0x80000000 for on or 0x00000000 for off but I've seen nothing else mentioned.But, kernel parameter meaning should differ from CPU l2cr register and maybe other L2 parameters should be set. But this I don't understand.
I will try l2cr=3 on weekend and we will see.
Also, there is l3cr if you want to experiment. Unfortunately you will need to consult the technical guide again.
https://docs.kernel.org/admin-guide/ker ... eters.html