__bss_start and __bss_end are empty about rust-raspberrypi-os-tutorials HOT 2 CLOSED

Hi,

I think what you actually wanted is

panic!(
    "Bss start:{:?}, end:{:?}",
    &__bss_start as *const usize, &__bss_end as *const usize
);

You were reading the contents at the symbol address (the memory there is probably uninitialized and can therefore have random content).

In your case, you want the symbol's address/location.
That is one of the more confusing parts everybody learning OS dev will once stumble upon.

Some resources:
https://en.wikipedia.org/wiki/Symbol_table
https://wiki.osdev.org/Linker_Scripts

By the way, for looking at the bss symbols, the Makefiles provide a handy command already:

make nm

Best,
Andre

from rust-raspberrypi-os-tutorials.

Thank you very much for your fast and insightful answer! You were right, and thanks for pointing me to nm of which I wasn't aware of.

from rust-raspberrypi-os-tutorials.