I use a Cortex-A7 board and write start up code.
I try to use Security Extension.
I use `smc` instruction and make cpu mode monitor mode.
In the monitor handler, I tried to changed stack pointer value for calling other functions.
But after execute `ldr sp, =_stack_start`, sp value is 0x0 (Of course, _stack_start is not 0x0 and I check it in the assembler code).
Therefore, after `push` some registers and `pop` those registers, the data abort excetpions occurred!
How can I change the sp value?
You are not debugging on RPi2 by any chance?
In that case you need to use the GPIO pins + a boot program to switch the
multiplexed GPIO pins for that use. The two jtag-connectors are for LAN-chip and for GPU.
Even if the cores are on the same chip as the GPU, (I'm told) the cores are not in the same
scan chain with the GPU.
I previously used SEGGER J-Link and SEGGER's gdb server to debug this board.
It works without any board specific options. I don't need to write such a special program too.
Therefore, I assume some parameters in my configuration file would be incorrect and no additional procedure such as RPi2 would be needed.
Is this of any help?
http://www.tincantools.com/wiki/OpenOCD_Troubleshooting:_JTAG_Tap_Unexpected
This may be of help too.
http://openocd.org/doc/html/Debug-Adapter-Configuration.html
This makes me think maybe you should try cmsis-dap driver.
https://community.freescale.com/thread/337734