fix,refactor,docs: misc. preparations for UEFI

README.md

@@ -1,6 +1,6 @@
 # The Hermit Loader
 
-This project is a loader to run the [Hermit kernel](https://github.com/hermitcore/kernel) within [QEMU](https://www.qemu.org).
+This project is a bootloader to run the [Hermit kernel](https://github.com/hermitcore/kernel) in different environments.
 
 ## Requirements
 
@@ -9,21 +9,21 @@ This project is a loader to run the [Hermit kernel](https://github.com/hermitcor
 ## Building
 
 ```bash
-$ cargo xtask build --target <TARGET> --release
+cargo xtask build --target <TARGET> --release
 ```
 
-With `<TARGET>` being either `x86_64`, `x86_64-uefi`, or `aarch64`.
+With `<TARGET>` being either `x86_64`, `x86_64-uefi`, `aarch64`, or `riscv64`.
 
-Afterward, the loader is located at `target/<TARGET>/release/hermit-loader`.
+Afterward, the loader is located in `target/release`.
 
 ## Running
 
 ### x86-64
 
 On x86-64 Linux with KVM, you can boot Hermit like this:
 
-```
-$ qemu-system-x86_64 \
+```bash
+qemu-system-x86_64 \
     -enable-kvm \
     -cpu host \
     -smp 1 \
@@ -46,17 +46,17 @@ If you want to benchmark Hermit, make sure to enable the _invariant TSC_ (`invts
 
 Unikernel arguments can be provided like this:
 
-```
-$ qemu-system-x86_64 ... \
+```bash
+qemu-system-x86_64 ... \
     -append "[KERNEL_ARGS] [--] [APP_ARGS]"
 ```
 
 ### AArch64
 
 On AArch64, the base command is as follows:
 
-```
-$ qemu-system-aarch64 \
+```bash
+qemu-system-aarch64 \
                   -machine virt,gic-version=3 \
                   -cpu cortex-a76 \
                   -smp 1 \
@@ -126,8 +126,8 @@ Microvms have a smaller memory footprint and a faster boot time.
 
 To use this VM type, PCI and ACPI support have to be disabled for your app (using `no-default-features`).
 
-```
-$ qemu-system-x86_64 ... \
+```bash
+qemu-system-x86_64 ... \
     -M microvm,x-option-roms=off,pit=off,pic=off,rtc=on,auto-kernel-cmdline=off \
     -nodefaults -no-user-config \
     -append "-freq 2800"
@@ -140,24 +140,24 @@ Depending on the virtualized processor, the processor frequency has to be passed
 To enable an Ethernet device, we have to set up a tap device on the host system.
 The following commands establish the tap device `tap10` on Linux:
 
-```
-# ip tuntap add tap10 mode tap
-# ip addr add 10.0.5.1/24 broadcast 10.0.5.255 dev tap10
-# ip link set dev tap10 up
-# echo 1 > /proc/sys/net/ipv4/conf/tap10/proxy_arp
+```bash
+ip tuntap add tap10 mode tap
+ip addr add 10.0.5.1/24 broadcast 10.0.5.255 dev tap10
+ip link set dev tap10 up
+echo 1 > /proc/sys/net/ipv4/conf/tap10/proxy_arp
 ```
 
 If you want Hermit to be accessible from outside the host, you have to enable IP forwarding:
-```
-# sysctl -w net.ipv4.ip_forward=1
+```bash
+sysctl -w net.ipv4.ip_forward=1
 ```
 
 You need to enable the `tcp` feature of the kernel.
 
 The network configuration can be set via environment variables during compile time.
 By default, it is:
 
-```
+```bash
 HERMIT_IP="10.0.5.3"
 HERMIT_GATEWAY="10.0.5.1"
 HERMIT_MASK="255.255.255.0"
@@ -167,8 +167,8 @@ Currently, Hermit only supports [Virtio]:
 
 [Virtio]: https://www.redhat.com/en/blog/introduction-virtio-networking-and-vhost-net
 
-```
-$ qemu-system-x86_64 ... \
+```bash
+qemu-system-x86_64 ... \
     -netdev tap,id=net0,ifname=tap10,script=no,downscript=no,vhost=on \
     -device virtio-net-pci,netdev=net0,disable-legacy=on
 ```

src/arch/aarch64/mod.rs

@@ -17,6 +17,7 @@ use sptr::Strict;
 
 use crate::arch::paging::*;
 use crate::os::CONSOLE;
+use crate::BootInfoExt;
 
 extern "C" {
 	static loader_end: u8;
@@ -192,14 +193,6 @@ pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
 		);
 	}
 
-	let current_stack_address = load_info.kernel_image_addr_range.start - KERNEL_STACK_SIZE as u64;
-
-	take_static::take_static! {
-		static RAW_BOOT_INFO: Option<RawBootInfo> = None;
-	}
-
-	let raw_boot_info = RAW_BOOT_INFO.take().unwrap();
-
 	let dtb = unsafe {
 		Dtb::from_raw(sptr::from_exposed_addr(DEVICE_TREE as usize))
 			.expect(".dtb file has invalid header")
@@ -227,39 +220,36 @@ pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
 		platform_info: PlatformInfo::LinuxBoot,
 	};
 
-	info!("boot_info = {boot_info:#?}");
-	let boot_info_ptr = raw_boot_info.insert(RawBootInfo::from(boot_info));
-	info!("boot_info at {boot_info_ptr:p}");
+	let stack = boot_info.load_info.kernel_image_addr_range.start as usize - KERNEL_STACK_SIZE;
+	let stack = sptr::from_exposed_addr_mut(stack);
+	let entry = sptr::from_exposed_addr(entry_point.try_into().unwrap());
+	let raw_boot_info = boot_info.write();
+
+	unsafe { enter_kernel(stack, entry, raw_boot_info) }
+}
+
+unsafe fn enter_kernel(stack: *mut u8, entry: *const (), raw_boot_info: &'static RawBootInfo) -> ! {
+	// Check expected signature of entry function
+	let entry: Entry = {
+		let entry: unsafe extern "C" fn(raw_boot_info: &'static RawBootInfo, cpu_id: u32) -> ! =
+			unsafe { core::mem::transmute(entry) };
+		entry
+	};
 
-	// Jump to the kernel entry point and provide the Multiboot information to it.
-	info!(
-		"Jumping to HermitCore Application Entry Point at {:#x}",
-		entry_point
-	);
+	info!("Entering kernel at {entry:p}, stack at {stack:p}, raw_boot_info at {raw_boot_info:p}");
 
-	/* Memory barrier */
+	// Memory barrier
 	unsafe {
 		asm!("dsb sy", options(nostack));
 	}
 
-	#[allow(dead_code)]
-	const ENTRY_TYPE_CHECK: Entry = {
-		unsafe extern "C" fn entry_signature(
-			_raw_boot_info: &'static RawBootInfo,
-			_cpu_id: u32,
-		) -> ! {
-			unimplemented!()
-		}
-		entry_signature
-	};
-
 	unsafe {
 		asm!(
-			"mov sp, {stack_address}",
+			"mov sp, {stack}",
 			"br {entry}",
-			stack_address = in(reg) current_stack_address,
-			entry = in(reg) entry_point,
-			in("x0") boot_info_ptr,
+			stack = in(reg) stack,
+			entry = in(reg) entry,
+			in("x0") raw_boot_info,
 			in("x1") 0,
 			options(noreturn)
 		)

src/arch/riscv64/mod.rs

@@ -16,6 +16,8 @@ use hermit_entry::Entry;
 use log::info;
 use sptr::Strict;
 
+use crate::BootInfoExt;
+
 fn find_kernel_linux(chosen: &FdtNode<'_, '_>) -> Option<&'static [u8]> {
 	let initrd_start = chosen.property("linux,initrd-start")?.as_usize()?;
 	let initrd_start = sptr::from_exposed_addr_mut::<u8>(initrd_start);
@@ -96,14 +98,6 @@ pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
 
 	let fdt = start::get_fdt();
 
-	info!("hart_id = {}", start::get_hart_id());
-
-	take_static::take_static! {
-		static RAW_BOOT_INFO: Option<RawBootInfo> = None;
-	}
-
-	let raw_boot_info = RAW_BOOT_INFO.take().unwrap();
-
 	let phys_addr_range = {
 		let memory = fdt.memory();
 		let mut regions = memory.regions();
@@ -134,27 +128,37 @@ pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
 		platform_info: PlatformInfo::LinuxBoot,
 	};
 
-	info!("boot_info = {boot_info:#?}");
-	let boot_info_ptr = raw_boot_info.insert(RawBootInfo::from(boot_info));
-	info!("boot_info at {boot_info_ptr:p}");
+	let stack = start::get_stack_ptr();
+	let entry = sptr::from_exposed_addr(entry_point.try_into().unwrap());
+	let hart_id = start::get_hart_id();
+	let raw_boot_info = boot_info.write();
+
+	unsafe { enter_kernel(stack, entry, hart_id, raw_boot_info) }
+}
 
+unsafe fn enter_kernel(
+	stack: *mut u8,
+	entry: *const (),
+	hart_id: usize,
+	raw_boot_info: &'static RawBootInfo,
+) -> ! {
 	// Check expected signature of entry function
 	let entry: Entry = {
 		let entry: unsafe extern "C" fn(hart_id: usize, boot_info: &'static RawBootInfo) -> ! =
-			unsafe { core::mem::transmute(entry_point) };
+			unsafe { core::mem::transmute(entry) };
 		entry
 	};
 
-	info!("Jumping into kernel at {entry:p}");
+	info!("Entering kernel at {entry:p}, stack at {stack:p}, raw_boot_info at {raw_boot_info:p}");
 
 	unsafe {
 		asm!(
 			"mv sp, {stack}",
 			"jr {entry}",
 			entry = in(reg) entry,
-			stack = in(reg) start::get_stack_ptr(),
-			in("a0") start::get_hart_id(),
-			in("a1") boot_info_ptr,
+			stack = in(reg) stack,
+			in("a0") hart_id,
+			in("a1") raw_boot_info,
 			options(noreturn)
 		)
 	}

src/arch/x86_64/firecracker.rs

@@ -1,22 +1,21 @@
-use core::arch::asm;
 use core::ptr::write_bytes;
 use core::{ptr, slice};
 
 use align_address::Align;
-use hermit_entry::boot_info::{BootInfo, HardwareInfo, PlatformInfo, RawBootInfo, SerialPortBase};
+use hermit_entry::boot_info::{BootInfo, HardwareInfo, PlatformInfo, SerialPortBase};
 use hermit_entry::elf::LoadedKernel;
 use hermit_entry::fc::{
 	BOOT_FLAG_OFFSET, CMD_LINE_PTR_OFFSET, CMD_LINE_SIZE_OFFSET, E820_ENTRIES_OFFSET,
 	E820_TABLE_OFFSET, HDR_MAGIC_OFFSET, LINUX_KERNEL_BOOT_FLAG_MAGIC, LINUX_KERNEL_HRD_MAGIC,
 	LINUX_SETUP_HEADER_OFFSET, RAMDISK_IMAGE_OFFSET, RAMDISK_SIZE_OFFSET,
 };
-use hermit_entry::Entry;
 use log::info;
 use sptr::Strict;
 use x86_64::structures::paging::{PageSize, PageTableFlags, Size2MiB, Size4KiB};
 
 use super::physicalmem::PhysAlloc;
 use super::{paging, KERNEL_STACK_SIZE, SERIAL_IO_PORT};
+use crate::BootInfoExt;
 
 extern "C" {
 	static loader_end: u8;
@@ -151,13 +150,6 @@ pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
 		None
 	};
 
-	let current_stack_address = new_stack as u64;
-	info!(
-		"Use kernel stack:  [{:#x} - {:#x}]",
-		current_stack_address,
-		current_stack_address + KERNEL_STACK_SIZE
-	);
-
 	// map stack in the address space
 	paging::map::<Size4KiB>(
 		new_stack,
@@ -220,12 +212,6 @@ pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
 		start_address, end_address
 	);
 
-	take_static::take_static! {
-		static RAW_BOOT_INFO: Option<RawBootInfo> = None;
-	}
-
-	let raw_boot_info = RAW_BOOT_INFO.take().unwrap();
-
 	let boot_info = BootInfo {
 		hardware_info: HardwareInfo {
 			phys_addr_range: start_address as u64..end_address as u64,
@@ -239,36 +225,9 @@ pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
 		},
 	};
 
-	info!("boot_info = {boot_info:#?}");
-	let boot_info_ptr = raw_boot_info.insert(RawBootInfo::from(boot_info));
-	info!("boot_info at {boot_info_ptr:p}");
-
-	// Jump to the kernel entry point and provide the Multiboot information to it.
-	info!(
-		"Jumping to HermitCore Application Entry Point at {:#x}",
-		entry_point
-	);
+	let stack = sptr::from_exposed_addr_mut(new_stack);
+	let entry = sptr::from_exposed_addr(entry_point.try_into().unwrap());
+	let raw_boot_info = boot_info.write();
 
-	#[allow(dead_code)]
-	const ENTRY_TYPE_CHECK: Entry = {
-		unsafe extern "C" fn entry_signature(
-			_raw_boot_info: &'static RawBootInfo,
-			_cpu_id: u32,
-		) -> ! {
-			unimplemented!()
-		}
-		entry_signature
-	};
-
-	unsafe {
-		asm!(
-			"mov rsp, {stack_address}",
-			"jmp {entry}",
-			stack_address = in(reg) current_stack_address,
-			entry = in(reg) entry_point,
-			in("rdi") boot_info_ptr,
-			in("rsi") 0,
-			options(noreturn)
-		)
-	}
+	unsafe { super::enter_kernel(stack, entry, raw_boot_info) }
 }

src/arch/x86_64/mod.rs

@@ -44,3 +44,37 @@ pub unsafe fn get_memory(memory_size: u64) -> u64 {
 	let address = PhysAlloc::allocate((memory_size as usize).align_up(Size2MiB::SIZE as usize));
 	unsafe { map_memory(address, memory_size as usize) as u64 }
 }
+
+#[cfg(target_os = "none")]
+unsafe fn enter_kernel(
+	stack: *mut u8,
+	entry: *const (),
+	raw_boot_info: &'static hermit_entry::boot_info::RawBootInfo,
+) -> ! {
+	use core::arch::asm;
+
+	use hermit_entry::boot_info::RawBootInfo;
+	use hermit_entry::Entry;
+	use log::info;
+
+	// Check expected signature of entry function
+	let entry: Entry = {
+		let entry: unsafe extern "C" fn(raw_boot_info: &'static RawBootInfo, cpu_id: u32) -> ! =
+			unsafe { core::mem::transmute(entry) };
+		entry
+	};
+
+	info!("Entering kernel at {entry:p}, stack at {stack:p}, raw_boot_info at {raw_boot_info:p}");
+
+	unsafe {
+		asm!(
+			"mov rsp, {stack_address}",
+			"jmp {entry}",
+			stack_address = in(reg) stack,
+			entry = in(reg) entry,
+			in("rdi") raw_boot_info,
+			in("rsi") 0,
+			options(noreturn)
+		)
+	}
+}