minor changes to avoid issue 82523

- see also rust-lang/rust#82523

Author: stlankes

src/arch/x86_64/kernel/acpi.rs

@@ -412,7 +412,8 @@ fn parse_fadt(fadt: AcpiTable<'_>) {
 
 	// Map the "Differentiated System Description Table" (DSDT).
 	// TODO: This must not require "unsafe", see https://github.com/rust-lang/rust/issues/46043#issuecomment-393072398
-	let x_dsdt_field_address = unsafe { &fadt_table.x_dsdt as *const _ as usize };
+	let x_dsdt = core::ptr::addr_of!(fadt_table.x_dsdt);
+	let x_dsdt_field_address = unsafe { x_dsdt.read_unaligned() as usize };
 	let dsdt_address = if x_dsdt_field_address < fadt.table_end_address() && fadt_table.x_dsdt > 0 {
 		PhysAddr(fadt_table.x_dsdt)
 	} else {

src/arch/x86_64/kernel/apic.rs

@@ -233,13 +233,14 @@ fn detect_from_acpi() -> Result<PhysAddr, ()> {
 			1 => {
 				// I/O APIC
 				let ioapic_record = unsafe { &*(current_address as *const IoApicRecord) };
+				let ioapic_addr = core::ptr::addr_of!(ioapic_record.address);
 				debug!("Found I/O APIC record: {}", ioapic_record);
 
 				unsafe {
 					IOAPIC_ADDRESS = virtualmem::allocate(BasePageSize::SIZE).unwrap();
 					debug!(
 						"Mapping IOAPIC at {:#X} to virtual address {:#X}",
-						ioapic_record.address, IOAPIC_ADDRESS
+						ioapic_addr.read_unaligned(), IOAPIC_ADDRESS
 					);
 
 					let mut flags = PageTableEntryFlags::empty();