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integration-test: boot multiboot2_chainloader itself also via Multiboot2
Since I don't use QEMU Multiboot1-direct boot anymore, we can use Multiboot2 here as well. This also fights some problems with Limine which doesn't want to load the Multiboot1 kernel in an UEFI environment.
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12 files changed

+107
-99
lines changed

12 files changed

+107
-99
lines changed

‎integration-test/bins/Cargo.lock‎

Lines changed: 0 additions & 16 deletions
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‎integration-test/bins/multiboot2_chainloader/Cargo.toml‎

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -12,7 +12,6 @@ publish = false
1212
anyhow.workspace = true
1313
log.workspace = true
1414
good_memory_allocator.workspace = true
15-
multiboot = "0.8"
1615
multiboot2.workspace = true
1716
multiboot2-header.workspace = true
1817
util.workspace = true

‎integration-test/bins/multiboot2_chainloader/link.ld‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -11,9 +11,9 @@ PHDRS
1111

1212
SECTIONS {
1313
/* Chainloader linked at 8M, payload at 16M */
14-
.text 8M : AT(8M) ALIGN(4K)
14+
.text 12M : AT(12M) ALIGN(4K)
1515
{
16-
KEEP(*(.multiboot_header));
16+
KEEP(*(.multiboot2_header));
1717
*(.text .text.*)
1818
} : kernel_rx
1919

‎integration-test/bins/multiboot2_chainloader/src/loader.rs‎

Lines changed: 52 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -1,19 +1,58 @@
11
use alloc::boxed::Box;
2+
use alloc::vec::Vec;
23
use elf_rs::{ElfFile, ProgramHeaderEntry, ProgramType};
4+
use log::{debug, info};
35
use multiboot2::{
4-
BootLoaderNameTag, CommandLineTag, MaybeDynSized, MemoryArea, MemoryAreaType, MemoryMapTag,
5-
ModuleTag, SmbiosTag,
6+
BootLoaderNameTag, CommandLineTag, EFIMemoryAreaType, MaybeDynSized, MemoryArea,
7+
MemoryAreaType, MemoryMapTag, ModuleTag, SmbiosTag,
68
};
79

10+
fn get_free_mmap_areas(
11+
mbi: &multiboot2::BootInformation,
12+
) -> Vec<(u64 /* start */, u64 /* size */)> {
13+
match (mbi.memory_map_tag(), mbi.efi_memory_map_tag()) {
14+
(Some(mmt), None) => mmt
15+
.memory_areas()
16+
.iter()
17+
.filter(|ma| ma.typ() == MemoryAreaType::Available)
18+
.map(|ma| (ma.start_address(), ma.size()))
19+
.collect::<alloc::vec::Vec<_>>(),
20+
(_, Some(mmt)) => mmt
21+
.memory_areas()
22+
.filter(|ma| ma.ty == EFIMemoryAreaType::CONVENTIONAL)
23+
.map(|ma| (ma.phys_start, ma.page_count * 4096))
24+
.collect::<alloc::vec::Vec<_>>(),
25+
_ => panic!("No usable memory map"),
26+
}
27+
}
28+
29+
fn assert_load_segment_fits_into_memory(
30+
start: u64,
31+
size: u64,
32+
free_areas: &[(u64 /* start */, u64 /* size */)],
33+
) {
34+
let end = start + size;
35+
let range = free_areas
36+
.iter()
37+
.find(|(a_start, a_size)| start >= *a_start && end <= a_start + a_size);
38+
if let Some(range) = range {
39+
debug!("Can load load segment (0x{start:x?}, {size:x?}) into free memory area {range:#x?}");
40+
} else {
41+
panic!("Can't load load segment (0x{start:x?}, {size:x?}) into any area!");
42+
}
43+
}
44+
845
/// Loads the first module into memory. Assumes that the module is a ELF file.
946
/// The handoff is performed according to the Multiboot2 spec.
10-
pub fn load_module(mut modules: multiboot::information::ModuleIter) -> ! {
47+
pub fn load_module(mbi: &multiboot2::BootInformation) -> ! {
48+
let mut modules = mbi.module_tags();
49+
1150
// Load the ELF from the Multiboot1 boot module.
1251
let elf_mod = modules.next().expect("Should have payload");
1352
let elf_bytes = unsafe {
1453
core::slice::from_raw_parts(
15-
elf_mod.start as *const u64 as *const u8,
16-
(elf_mod.end - elf_mod.start) as usize,
54+
elf_mod.start_address() as *const u64 as *const u8,
55+
elf_mod.module_size() as usize,
1756
)
1857
};
1958
let elf = elf_rs::Elf32::from_bytes(elf_bytes).expect("Should be valid ELF");
@@ -28,10 +67,11 @@ pub fn load_module(mut modules: multiboot::information::ModuleIter) -> ! {
2867
log::info!("Multiboot2 header:\n{hdr:#?}");
2968
}
3069

31-
// Map the load segments into memory (at their corresponding link).
70+
// Load the load segments into memory (at their corresponding link address).
3271
{
33-
let elf = elf_rs::Elf32::from_bytes(elf_bytes).expect("Should be valid ELF");
72+
let free_areas = get_free_mmap_areas(mbi);
3473
elf.program_header_iter()
74+
.inspect(|ph| assert_load_segment_fits_into_memory(ph.vaddr(), ph.memsz(), &free_areas))
3575
.filter(|ph| ph.ph_type() == ProgramType::LOAD)
3676
.for_each(|ph| {
3777
map_memory(ph);
@@ -53,9 +93,9 @@ pub fn load_module(mut modules: multiboot::information::ModuleIter) -> ! {
5393
MemoryAreaType::Reserved,
5494
)]))
5595
.add_module(ModuleTag::new(
56-
elf_mod.start as u32,
57-
elf_mod.end as u32,
58-
elf_mod.string.unwrap(),
96+
elf_mod.start_address(),
97+
elf_mod.end_address(),
98+
elf_mod.cmdline().unwrap(),
5999
))
60100
// Test that we can add SmbiosTag multiple times.
61101
.add_smbios(SmbiosTag::new(1, 1, &[1, 2, 3]))
@@ -66,7 +106,7 @@ pub fn load_module(mut modules: multiboot::information::ModuleIter) -> ! {
66106

67107
log::info!(
68108
"Handing over to ELF: {}",
69-
elf_mod.string.unwrap_or("<unknown>")
109+
elf_mod.cmdline().unwrap_or("<unknown>")
70110
);
71111

72112
// handoff
@@ -84,7 +124,7 @@ pub fn load_module(mut modules: multiboot::information::ModuleIter) -> ! {
84124
/// address space. The loader assumes that the addresses to not clash with the
85125
/// loader (or anything else).
86126
fn map_memory(ph: ProgramHeaderEntry) {
87-
log::debug!("Mapping LOAD segment {ph:#?}");
127+
debug!("Mapping LOAD segment {ph:#?}");
88128
let dest_ptr = ph.vaddr() as *mut u8;
89129
let content = ph.content().expect("Should have content");
90130
unsafe { core::ptr::copy(content.as_ptr(), dest_ptr, content.len()) };

‎integration-test/bins/multiboot2_chainloader/src/main.rs‎

Lines changed: 18 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -2,7 +2,6 @@
22
#![no_std]
33

44
mod loader;
5-
mod multiboot;
65

76
extern crate alloc;
87

@@ -11,6 +10,7 @@ extern crate util;
1110

1211
use util::init_environment;
1312

13+
core::arch::global_asm!(include_str!("multiboot2_header.S"), options(att_syntax));
1414
core::arch::global_asm!(include_str!("start.S"), options(att_syntax));
1515

1616
/// Entry into the Rust code from assembly using the x86 SystemV calling
@@ -19,7 +19,21 @@ core::arch::global_asm!(include_str!("start.S"), options(att_syntax));
1919
fn rust_entry(multiboot_magic: u32, multiboot_hdr: *const u32) -> ! {
2020
init_environment();
2121
log::debug!("multiboot_hdr={multiboot_hdr:x?}, multiboot_magic=0x{multiboot_magic:x?}");
22-
let mbi = multiboot::get_mbi(multiboot_magic, multiboot_hdr as u32).unwrap();
23-
let module_iter = mbi.modules().expect("Should provide modules");
24-
loader::load_module(module_iter);
22+
assert_eq!(multiboot_magic, multiboot2::MAGIC);
23+
let mbi = unsafe { multiboot2::BootInformation::load(multiboot_hdr.cast()) }.unwrap();
24+
25+
if let Some(mmap) = mbi.efi_memory_map_tag() {
26+
log::debug!("efi memory map:",);
27+
for desc in mmap.memory_areas() {
28+
log::warn!(
29+
" start=0x{:016x?} size={:016x?} type={:?}, attr={:?}",
30+
desc.phys_start,
31+
desc.page_count * 4096,
32+
desc.ty,
33+
desc.att
34+
);
35+
}
36+
}
37+
38+
loader::load_module(&mbi);
2539
}

‎integration-test/bins/multiboot2_chainloader/src/multiboot.rs‎

Lines changed: 0 additions & 41 deletions
Original file line numberDiff line numberDiff line change
@@ -1,41 +0,0 @@
1-
//! Parsing the Multiboot information. Glue code for the [`multiboot`] code.
2-
3-
use anyhow::anyhow;
4-
use core::ptr::addr_of_mut;
5-
use core::slice;
6-
use multiboot::information::{MemoryManagement, Multiboot, PAddr, SIGNATURE_EAX};
7-
8-
static mut MEMORY_MANAGEMENT: Mem = Mem;
9-
10-
/// Returns an object to access the fields of the Multiboot information
11-
/// structure.
12-
pub fn get_mbi<'a>(magic: u32, ptr: u32) -> anyhow::Result<Multiboot<'a, 'static>> {
13-
if magic != SIGNATURE_EAX {
14-
return Err(anyhow!("Unknown Multiboot signature {magic:x}"));
15-
}
16-
let mmgmt: &mut dyn MemoryManagement = unsafe { &mut *addr_of_mut!(MEMORY_MANAGEMENT) };
17-
unsafe { Multiboot::from_ptr(ptr as u64, mmgmt) }.ok_or(anyhow!(
18-
"Can't read Multiboot boot information from pointer"
19-
))
20-
}
21-
22-
/// Glue object between the global allocator and the multiboot crate.
23-
struct Mem;
24-
25-
impl MemoryManagement for Mem {
26-
unsafe fn paddr_to_slice(&self, addr: PAddr, size: usize) -> Option<&'static [u8]> {
27-
let ptr = addr as *const u64 as *const u8;
28-
Some(unsafe { slice::from_raw_parts(ptr, size) })
29-
}
30-
31-
// If you only want to read fields, you can simply return `None`.
32-
unsafe fn allocate(&mut self, _length: usize) -> Option<(PAddr, &mut [u8])> {
33-
None
34-
}
35-
36-
unsafe fn deallocate(&mut self, addr: PAddr) {
37-
if addr != 0 {
38-
unimplemented!()
39-
}
40-
}
41-
}

‎integration-test/bins/multiboot2_chainloader/src/multiboot2_header.S‎

Lines changed: 25 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,25 @@
1+
# The assembly code uses the GNU Assembly (GAS) flavor with Intel noprefix
2+
# syntax.
3+
4+
# Symbol from main.rs
5+
.EXTERN start
6+
7+
.code32
8+
.align 8
9+
.section .multiboot2_header
10+
11+
mb2_header_start:
12+
.long 0xe85250d6 # magic number
13+
.long 0 # architecture 0 (protected mode i386)
14+
.long mb2_header_end - mb2_header_start # header length
15+
# checksum
16+
.long 0x100000000 - (0xe85250d6 + 0 + (mb2_header_end - mb2_header_start))
17+
18+
# REQUIRED END TAG
19+
.align 8
20+
.Lmb2_header_tag_end_start:
21+
.word 0 # type (16bit)
22+
.word 0 # flags (16bit)
23+
.long .Lmb2_header_tag_end_end - .Lmb2_header_tag_end_start # size (32bit)
24+
.Lmb2_header_tag_end_end:
25+
mb2_header_end:

‎integration-test/bins/multiboot2_chainloader/src/start.S‎

Lines changed: 0 additions & 13 deletions
Original file line numberDiff line numberDiff line change
@@ -3,19 +3,6 @@
33

44
.code32
55

6-
.section .multiboot_header, "a", @progbits
7-
8-
/*
9-
* Multiboot v1 Header.
10-
* Required so that we can be booted by QEMU via the "-kernel" parameter.
11-
*/
12-
.align 8
13-
.global multiboot_header
14-
multiboot_header:
15-
.long 0x1badb002
16-
.long 0x0
17-
.long -0x1badb002
18-
196
.section .text
207

218
.global start

‎integration-test/bins/multiboot2_payload/link.ld‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -11,9 +11,9 @@ PHDRS
1111

1212
SECTIONS {
1313
/* Chainloader linked at 8M, payload at 16M */
14-
.text 16M : AT(16M) ALIGN(4K)
14+
.text 24M : AT(24M) ALIGN(4K)
1515
{
16-
*(.multiboot2_header)
16+
KEEP(*(.multiboot2_header));
1717
*(.text .text.*)
1818
} : kernel_rx
1919

‎integration-test/bins/util/src/allocator.rs‎

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -1,10 +1,10 @@
11
use good_memory_allocator::SpinLockedAllocator;
22

3-
#[repr(align(0x4000))]
4-
struct Align16K<T>(T);
3+
#[repr(align(0x1000))]
4+
struct PageAlign<T>(T);
55

6-
/// 16 KiB naturally aligned backing storage for heap.
7-
static mut HEAP: Align16K<[u8; 0x4000]> = Align16K([0; 0x4000]);
6+
/// 16 KiB page-aligned backing storage for heap.
7+
static mut HEAP: PageAlign<[u8; 0x4000]> = PageAlign([0; 0x4000]);
88

99
#[global_allocator]
1010
static ALLOCATOR: SpinLockedAllocator = SpinLockedAllocator::empty();

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