Unsafety in `Madt::entries`

[pyelias]

If you copy a Madt out of its PhysicalMapping, entries will take entries from the memory after the copy, not from the PhysicalMapping's memory.

let madt: Madt = *acpi_tables.find_table::<Madt>().unwrap();
for entry in madt.entries() {
    // entry will have bad data
}

This could be fixed by forcing entries to take a PhysicalMapping<_, Madt> and verify its size.

[IsaacWoods]

Apologies for the delay in getting back to you, and thank you for taking the time to report this! This is indeed unsound unfortunately.

We couldn't do a straight swap to taking a PhysicalMapping on entries I don't think without making it a free function. I wonder if we can instead use Pin to stop tables that are larger than our representations of them being moved - I'll have a play around and see what I can do.