Merge pull request #1279 from hermit-os/fdt-print

feat(x86_64): print FDT

Cargo.toml

@@ -86,7 +86,7 @@ build-time = "0.1.3"
 cfg-if = "1"
 crossbeam-utils = { version = "0.8", default-features = false }
 dyn-clone = "1.0"
-fdt = "0.1"
+fdt = { version = "0.1", features = ["pretty-printing"] }
 free-list = "0.3"
 hashbrown = { version = "0.14", default-features = false }
 hermit-entry = { version = "0.10", features = ["kernel"] }

src/arch/x86_64/kernel/mod.rs

@@ -4,6 +4,7 @@ use core::num::NonZeroU64;
 use core::ptr;
 use core::sync::atomic::{AtomicPtr, AtomicU32, Ordering};
 
+use fdt::Fdt;
 use hermit_entry::boot_info::{BootInfo, PlatformInfo, RawBootInfo};
 use hermit_sync::InterruptSpinMutex;
 use x86::controlregs::{cr0, cr0_write, cr4, Cr0};
@@ -81,11 +82,11 @@ pub fn get_mbinfo() -> Option<NonZeroU64> {
 	}
 }
 
-pub fn get_fdt() -> Option<usize> {
-	boot_info()
-		.hardware_info
-		.device_tree
-		.map(|fdt| fdt.get() as usize)
+pub fn get_fdt() -> Option<Fdt<'static>> {
+	boot_info().hardware_info.device_tree.map(|fdt| {
+		let ptr = ptr::with_exposed_provenance(fdt.get().try_into().unwrap());
+		unsafe { Fdt::from_ptr(ptr).unwrap() }
+	})
 }
 
 #[cfg(feature = "smp")]

src/arch/x86_64/mm/physicalmem.rs

@@ -18,8 +18,7 @@ const KVM_32BIT_GAP_SIZE: usize = 768 << 20;
 const KVM_32BIT_GAP_START: usize = KVM_32BIT_MAX_MEM_SIZE - KVM_32BIT_GAP_SIZE;
 
 fn detect_from_fdt() -> Result<(), ()> {
-	let fdt_addr = get_fdt().ok_or(())?;
-	let fdt = unsafe { fdt::Fdt::from_ptr(fdt_addr as *const u8).unwrap() };
+	let fdt = get_fdt().ok_or(())?;
 
 	let mems = fdt.find_all_nodes("/memory");
 	let all_regions = mems.map(|m| m.reg().unwrap().next().unwrap());

src/lib.rs

@@ -193,6 +193,11 @@ fn boot_processor_main() -> ! {
 	info!("Welcome to Hermit {}", env!("CARGO_PKG_VERSION"));
 	info!("Kernel starts at {:p}", env::get_base_address());
 
+	#[cfg(target_arch = "x86_64")]
+	if let Some(fdt) = kernel::get_fdt() {
+		info!("FDT:\n{fdt:#?}");
+	}
+
 	extern "C" {
 		static mut __bss_start: u8;
 	}