Create devicetree for x86_64

Pass memory region infomation from devicetree

Cargo.toml

@@ -11,6 +11,7 @@ align-address = "0.1"
 hermit-entry = { version = "0.9", features = ["loader"] }
 log = "0.4"
 sptr = "0.3"
+vm-fdt = { version = "0.3", default-features = false, features = ["alloc"] }
 
 [features]
 default = []

src/arch/x86_64/fdt.rs

@@ -0,0 +1,49 @@
+use alloc::format;
+
+use multiboot::information::{MemoryType, Multiboot};
+use vm_fdt::{Error as FdtError, FdtWriter};
+
+use super::{mb_info, MEM};
+
+pub struct DeviceTree;
+
+impl DeviceTree {
+	#[cfg(all(target_os = "none", not(feature = "fc")))]
+	pub fn create() -> Result<&'static [u8], FdtError> {
+		let multiboot = unsafe { Multiboot::from_ptr(mb_info as u64, &mut MEM).unwrap() };
+
+		let all_regions = multiboot
+			.memory_regions()
+			.expect("Could not find a memory map in the Multiboot information");
+		let ram_regions = all_regions.filter(|m| m.memory_type() == MemoryType::Available);
+
+		let mut fdt = FdtWriter::new()?;
+
+		let root_node = fdt.begin_node("")?;
+		fdt.property_string("compatible", "linux,dummy-virt")?;
+		fdt.property_u32("#address-cells", 0x2)?;
+		fdt.property_u32("#size-cells", 0x2)?;
+
+		if let Some(cmdline) = multiboot.command_line() {
+			let chosen_node = fdt.begin_node("chosen")?;
+			fdt.property_string("bootargs", cmdline)?;
+			fdt.end_node(chosen_node)?;
+		}
+
+		for m in ram_regions {
+			let start_address = m.base_address();
+			let length = m.length();
+
+			let memory_node = fdt.begin_node(format!("memory@{:x}", start_address).as_str())?;
+			fdt.property_string("device_type", "memory")?;
+			fdt.property_array_u64("reg", &[start_address, length])?;
+			fdt.end_node(memory_node)?;
+		}
+
+		fdt.end_node(root_node)?;
+
+		let fdt = fdt.finish()?;
+
+		Ok(fdt.leak())
+	}
+}

src/arch/x86_64/mod.rs

@@ -1,3 +1,5 @@
+#[cfg(all(target_os = "none", not(feature = "fc")))]
+mod fdt;
 mod paging;
 mod physicalmem;
 
@@ -10,6 +12,8 @@ use core::ptr::write_bytes;
 use core::slice;
 
 use align_address::Align;
+#[cfg(all(target_os = "none", not(feature = "fc")))]
+use hermit_entry::boot_info::DeviceTreeAddress;
 use hermit_entry::boot_info::{BootInfo, HardwareInfo, PlatformInfo, RawBootInfo, SerialPortBase};
 use hermit_entry::elf::LoadedKernel;
 #[cfg(all(target_os = "none", feature = "fc"))]
@@ -27,6 +31,8 @@ use multiboot::information::{Multiboot, PAddr};
 use uart_16550::SerialPort;
 use x86_64::structures::paging::{PageSize, PageTableFlags, Size2MiB, Size4KiB};
 
+#[cfg(all(target_os = "none", not(feature = "fc")))]
+use self::fdt::DeviceTree;
 use self::physicalmem::PhysAlloc;
 
 #[cfg(target_os = "none")]
@@ -472,14 +478,16 @@ pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
 		);
 	}
 
+	let device_tree = DeviceTree::create().expect("Unable to create devicetree!");
+
 	static mut BOOT_INFO: Option<RawBootInfo> = None;
 
 	let boot_info = {
 		let boot_info = BootInfo {
 			hardware_info: HardwareInfo {
 				phys_addr_range: 0..0,
 				serial_port_base: SerialPortBase::new(SERIAL_IO_PORT),
-				device_tree: None,
+				device_tree: DeviceTreeAddress::new(device_tree.as_ptr() as u64),
 			},
 			load_info,
 			platform_info: PlatformInfo::Multiboot {

src/main.rs

@@ -20,6 +20,9 @@ mod none;
 #[cfg(target_os = "uefi")]
 mod uefi;
 
+#[cfg(all(target_arch = "x86_64", target_os = "none", not(feature = "fc")))]
+extern crate alloc;
+
 #[cfg(target_os = "none")]
 #[doc(hidden)]
 fn _print(args: core::fmt::Arguments<'_>) {