feat(env): drop support for non-FDT RAM get_ram_address

Author: mkroening

src/env/mod.rs

@@ -65,8 +65,11 @@ pub fn fdt() -> Option<Fdt<'static>> {
 	})
 }
 
-pub(crate) fn get_ram_address() -> PhysAddr {
-	PhysAddr::new(boot_info().hardware_info.phys_addr_range.start)
+pub(crate) fn get_ram_address() -> Option<PhysAddr> {
+	let fdt = fdt()?;
+	let memory = fdt.memory();
+	let ptr = memory.regions().next()?.starting_address;
+	Some(ptr.expose_provenance().into())
 }
 
 /// Returns the RSDP physical address if available.

src/mm/mod.rs

@@ -147,8 +147,8 @@ pub(crate) fn init() {
 		// On UEFI, the given memory is guaranteed free memory and the kernel is located before the given memory
 		reserved_space
 	} else {
-		(kernel_addr_range.end.as_u64() - env::get_ram_address().as_u64() + reserved_space as u64)
-			as usize
+		(kernel_addr_range.end.as_u64() - env::get_ram_address().unwrap().as_u64()
+			+ reserved_space as u64) as usize
 	};
 	info!("Minimum memory size: {} MiB", min_mem >> 20);
 	let avail_mem = total_mem