Hi,
i want to boot a little kernel on ARM Cortex a9. But the kernel crushes pretty early with the following u-boot output:
## Starting application at 0x01000000 ... ## Application terminated, rc = 0x1
What board do you use? This address may be used by something different than application code.
Since i have no clue where (and how) to start debugging, my first question is:
What may cause "Application terminated, rc = 0x1"?
This message is located in two places: common/cmd_boot.c -> do_go() common/cmd_elf.c -> do_bootelf()
In both places it prints return value of your application (value of R0 after control is passed back to u-boot). What command do you use to start application? First option (cmd_boot -> do_go -> do_go_exec) may use do_go_exec() implementation from arch/arm/lib/cmd_boot.c that forces Thumb mode and I'm not sure whether it's OK for your application.
There must be any other issue. But how to find out what's wrong?
Please, any advice for debugging, or any hint about what may cause rc=0x1 is welcome.
arm-none-eabi-gdb + OpenOCD + JTAG dongles is a nice setup for debugging. If you have JTAG dongle, you can build U-Boot with debug information, set temporary breakpoint on do_go and do_bootelf functions, let the CPU run till one of these points and then single-step to the entry point of your application and further.
Debugging without JTAG is possible but it's a hard way. As a first attempt you can start with verifying that "int main(){ return 2; }" shows "Application terminated, rc = 0x2" and if it doesn't happen, you should look at the disassembly of your application. Btw, did you try applications from examples?