Hello, I am trying to run a "hello world" program with C/C++ standard library support on Morello board (hardware), using Arm Development Studio Morello edition.
I previously followed the standalone-baremetal-readme.rst guide which worked well (following the advice from this topic), but it did not allow to use functions like "printf".
I tried to use examples from:
I ran make and the "make-bm-image.sh" with "-e" flag to produce "howdy-purecap-bm-image.elf" and "howdy-morello-bm-image.elf" (in the "make-bm-image.sh" script I added a line to preserve a copy of the .elf file), then I loaded these in the development studio.
It appears that the program goes to address 0x200 after executing the "MRS" instruction.
Does anyone know why that happens?
Also, in the standalone-baremetal-readme.rst guide it was necessary to specify UART address (0x2A400000) in the program, is it correct to assume that examples from baremetal-release-1.6 branch of llvm-project-releases will use that address (without the need to specify it anywhere in the program) and the printf/cout messages will appear in the AP com port of Morello hardware board? Or is it necessary to do some adjustments to achieve that?
I rebooted the board and it seems that now DCC_EL2 is not null anymore (at the beginning of execution), and the LDR instruction is executed well.
I wrongly assumed that changing "Rainier_0" to "Rainier_SMP_0" or "Rainierx4 Multi-Cluster SMP" made the LDR fail, I think it was coincidence, because changing these 3 options now does not make LDR fail anymore (following reboot which fixed DCC_EL2 being 0).
But the issue where the function enters "curr_sp0_fiq" recursively after being stepped-over is still there.
I've set a hardware breakpoint on the "curr_sp0_fiq" and 0xE0002200, I used F5 to step until the first function call (which was _cpu_init_hook) and pressed F6 to step-over it, the breakpoint got triggered and registers values are:
I tried expanding the column and copying the text to see if there's something after "following..." but there was nothing, this is what it looks like when using tooltip:
The DDC_EL2 seems to keep the same value as at the beginning of execution, I think there may be 2 separate issues, DDC sometimes being 0 (which gets fixed by rebooting the board), and this unidentified issue when stepping-over function call. The ELR_EL2 points to the instruction just after the _cpu_init_hook call.
I did another experiment, where I pressed "continue" button (from the beginning of "_start" function) instead of using F5 to reach the 1st function call. Interestingly, in this case the breakpoint is hit with ELR_EL2 having much higher value (part of _get_s function), where DDC_EL2 becomes 0.
Apologies for bombarding with all these screenshots/reports but it's all black magic to me, and I can't understand why such weird issues could occur.