2025-04-18 13:26:16 +08:00

217 lines
7.7 KiB
Rust

// SPDX-License-Identifier: MPL-2.0
//! The Linux 64-bit Boot Protocol supporting module.
//!
use linux_boot_params::{BootParams, E820Type, LINUX_BOOT_HEADER_MAGIC};
#[cfg(feature = "cvm_guest")]
use crate::arch::x86::init_cvm_guest;
use crate::{
arch::x86::if_tdx_enabled,
boot::{
memory_region::{MemoryRegion, MemoryRegionArray, MemoryRegionType},
BootloaderAcpiArg, BootloaderFramebufferArg,
},
mm::kspace::paddr_to_vaddr,
};
fn parse_bootloader_name(boot_params: &BootParams) -> &str {
// The bootloaders have assigned IDs in Linux, see
// https://www.kernel.org/doc/Documentation/x86/boot.txt
// for details.
match boot_params.hdr.type_of_loader {
0x0 => "LILO", // (0x00 reserved for pre-2.00 bootloader)
0x1 => "Loadlin",
0x2 => "bootsect-loader", // (0x20, all other values reserved)
0x3 => "Syslinux",
0x4 => "Etherboot/gPXE/iPXE",
0x5 => "ELILO",
0x7 => "GRUB",
0x8 => "U-Boot",
0x9 => "Xen",
0xA => "Gujin",
0xB => "Qemu",
0xC => "Arcturus Networks uCbootloader",
0xD => "kexec-tools",
0xE => "Extended loader",
0xF => "Special", // (0xFF = undefined)
0x10 => "Reserved",
0x11 => "Minimal Linux Bootloader <http://sebastian-plotz.blogspot.de>",
0x12 => "OVMF UEFI virtualization stack",
_ => "Unknown Linux Loader",
}
}
fn parse_kernel_commandline(boot_params: &BootParams) -> Option<&str> {
if boot_params.ext_cmd_line_ptr != 0 {
// TODO: We can support the above 4GiB command line after setting up
// linear mappings. By far, we cannot log the error because the serial is
// not up. Proceed as if there was no command line.
return None;
}
if boot_params.hdr.cmd_line_ptr == 0 || boot_params.hdr.cmdline_size == 0 {
return None;
}
let cmdline_ptr = paddr_to_vaddr(boot_params.hdr.cmd_line_ptr as usize);
let cmdline_len = boot_params.hdr.cmdline_size as usize;
// SAFETY: The command line is safe to read because of the contract with the loader.
let cmdline = unsafe { core::slice::from_raw_parts(cmdline_ptr as *const u8, cmdline_len) };
// Now, unfortunately, there are silent errors because the serial is not up.
core::ffi::CStr::from_bytes_until_nul(cmdline)
.ok()?
.to_str()
.ok()
}
fn parse_initramfs(boot_params: &BootParams) -> Option<&[u8]> {
if boot_params.ext_ramdisk_image != 0 || boot_params.ext_ramdisk_size != 0 {
// See the explanation in `parse_kernel_commandline`.
return None;
}
if boot_params.hdr.ramdisk_image == 0 || boot_params.hdr.ramdisk_size == 0 {
return None;
}
let initramfs_ptr = paddr_to_vaddr(boot_params.hdr.ramdisk_image as usize);
let initramfs_len = boot_params.hdr.ramdisk_size as usize;
// SAFETY: The initramfs is safe to read because of the contract with the loader.
let initramfs =
unsafe { core::slice::from_raw_parts(initramfs_ptr as *const u8, initramfs_len) };
Some(initramfs)
}
fn parse_acpi_arg(boot_params: &BootParams) -> BootloaderAcpiArg {
let rsdp = boot_params.acpi_rsdp_addr;
if rsdp == 0 {
BootloaderAcpiArg::NotProvided
} else {
BootloaderAcpiArg::Rsdp(rsdp.try_into().expect("RSDP address overflowed!"))
}
}
fn parse_framebuffer_info(boot_params: &BootParams) -> Option<BootloaderFramebufferArg> {
let screen_info = boot_params.screen_info;
let address = screen_info.lfb_base as usize | ((screen_info.ext_lfb_base as usize) << 32);
if address == 0 {
return None;
}
Some(BootloaderFramebufferArg {
address,
width: screen_info.lfb_width as usize,
height: screen_info.lfb_height as usize,
bpp: screen_info.lfb_depth as usize,
})
}
impl From<E820Type> for MemoryRegionType {
fn from(value: E820Type) -> Self {
match value {
E820Type::Ram => Self::Usable,
E820Type::Reserved => Self::Reserved,
E820Type::Acpi => Self::Reclaimable,
E820Type::Nvs => Self::NonVolatileSleep,
E820Type::Unusable => Self::BadMemory,
// All other memory regions are reserved.
// FIXME: Using Rust enum in this way can be unsound if the bootloader passes an
// unknown memory type to the kernel (e.g., due to a newer protocol version).
_ => Self::Reserved,
}
}
}
fn parse_memory_regions(boot_params: &BootParams) -> MemoryRegionArray {
let mut regions = MemoryRegionArray::new();
// Add regions from E820.
let num_entries = boot_params.e820_entries as usize;
for e820_entry in &boot_params.e820_table[0..num_entries] {
regions
.push(MemoryRegion::new(
e820_entry.addr.try_into().unwrap(),
e820_entry.size.try_into().unwrap(),
e820_entry.typ.into(),
))
.unwrap();
}
// Add the framebuffer region.
if let Some(fb) = parse_framebuffer_info(boot_params) {
regions.push(MemoryRegion::framebuffer(&fb)).unwrap();
}
// Add the kernel region.
regions.push(MemoryRegion::kernel()).unwrap();
// Add the initramfs region.
if let Some(initramfs) = parse_initramfs(boot_params) {
regions.push(MemoryRegion::module(initramfs)).unwrap();
}
// Add the AP boot code region that will be copied into by the BSP.
regions
.push(super::smp::reclaimable_memory_region())
.unwrap();
// Add the region of the kernel cmdline since some bootloaders do not provide it.
if let Some(kcmdline) = parse_kernel_commandline(boot_params) {
regions
.push(MemoryRegion::module(kcmdline.as_bytes()))
.unwrap();
}
// FIXME: Early versions of TDVF did not correctly report the location of AP's page tables as
// EfiACPIMemoryNVS. We need to manually reserve this memory region to prevent them from being
// corrupted. TDVF has now been upstreamed to OVMF, and this issue has been fixed in OVMF
// stable-202411 or later. See the commit for details:
// <https://github.com/tianocore/edk2/commit/383f729ac096b8deb279933fce86e83a5f7f5ec7>.
if_tdx_enabled!({
// The definition of these constants can be found in:
// <https://github.com/tianocore/edk2/blob/a7ab45ace25c4b987994158687d04de07ed20a96/OvmfPkg/IntelTdx/IntelTdxX64.fdf#L64-L71>
// <https://github.com/tianocore/edk2/blob/a7ab45ace25c4b987994158687d04de07ed20a96/OvmfPkg/Include/Fdf/OvmfPkgDefines.fdf.inc#L106>
regions
.push(MemoryRegion::new(
// PcdOvmfSecPageTablesBase = $(MEMFD_BASE_ADDRESS) + 0x000000 = 0x800000
0x800000,
// PcdOvmfSecPageTablesSize = 0x006000
0x006000,
// EfiACPIMemoryNVS
MemoryRegionType::NonVolatileSleep,
))
.unwrap();
});
regions.into_non_overlapping()
}
/// The entry point of the Rust code portion of Asterinas.
#[no_mangle]
unsafe extern "sysv64" fn __linux_boot(params_ptr: *const BootParams) -> ! {
let params = unsafe { &*params_ptr };
assert_eq!({ params.hdr.header }, LINUX_BOOT_HEADER_MAGIC);
use crate::boot::{call_ostd_main, EarlyBootInfo, EARLY_INFO};
#[cfg(feature = "cvm_guest")]
init_cvm_guest();
EARLY_INFO.call_once(|| EarlyBootInfo {
bootloader_name: parse_bootloader_name(params),
kernel_cmdline: parse_kernel_commandline(params).unwrap_or(""),
initramfs: parse_initramfs(params),
acpi_arg: parse_acpi_arg(params),
framebuffer_arg: parse_framebuffer_info(params),
memory_regions: parse_memory_regions(params),
});
call_ostd_main();
}