Re: Hello world example with qemu-system-arm

[Peter Maydell]

On Mon, 16 May 2022 at 23:26, James Gutbub <jgutbub@asu.edu> wrote:
>
> Thank you for the help. I tried specifying ‘-R 0’ and receive the same error 
> message - qemu-arm: Unable to reserve 0xffff0000 bytes of virtual address 
> space at 0x1000 (Permission denied) for use as guest address space (check 
> your virtual memory ulimit setting, min_mmap_addr or reserve less using -R 
> option)
>
> I have been using the default linker script provided by arm-none-eabi-ld but 
> I will continue by using the linker script defined below, which gives the 
> same error message as before.
>
> test.ld file contents:
>
> ENTRY(_Reset)
> SECTIONS
> {
> . = 0x0000000;
> .startup . : { startup.o(.text)}
> .text : { *(.text) }
> . = 0x8000000;
> .data : { *(.data) }
> .bss : { *(.bss COMMON) }
> . = ALIGN(8);
> . = . + 0x1000;
> _stack = .;
> }

Bear in mind that you are essentially linking a Linux binary
here, not a real bare metal binary. So you don't necessarily get
full control over where you want to put stuff in the address space,
and in particular putting stuff at address 0 is not going to work.
(If you can use an arm-linux-* toolchain then you can likely get
away without having a linker map at all.)

-- PMM