thanks to ultimo and others I think I have the pi2 switching back to svc and secure mode now.

and other cleanup

aarch64/README

@@ -1,35 +0,0 @@
-
-Normally I prefer to not use a config.txt.  The standard boot files
-bootcode.bin, start.elf, and kernel7.img are how most of the raspberry
-pis in the world are used, booting linux.  Well tested.  config.txt
-creates exceptions to that, and from the early days of the raspi to
-the present some of these have come and gone.
-
-But...As of this writing in order to run 64 bit, from what the folks
-on the bare metal forums say, you have to use a config.txt containing
-
-arm_control=0x200
-kernel_old=1
-
-The bit set in arm_control indicates boot 64 bit not 32 bit.
-kernel_old tells the bootloader to not provide any boot code for the
-ARM (as of this writing that code is 32 bit instructions so wont work).
-
-This means we have to build our program for address 0x0000 not address
-0x8000 like we would normally.  This also means we have to deal with
-the other four cores.  When all the affinity bits are zero in the
-MPIDR_EL1 register, that is the master core.
-
-This relies on some SBZ/RES0 bits, but works for now to put the other
-cores in an infinite loop.
-
-    mrs x0,mpidr_el1
-    mov x1,#0xC1000000
-    bic x0,x0,x1
-    cbz x0,master
-    b .
-master:
-
-My build_gcc repository has a build_arm64 script that will build a
-gnu based toolchain that can be/was used to build these examples.
-