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diag: serial canary characters at kernel init checkpoints

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vasilito
2026-07-12 01:55:35 +03:00
parent 7a4bd3d491
commit 6e9613e67c
1 changed files with 34 additions and 0 deletions
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src/arch/x86_shared/start.rs
+34
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@@ -84,6 +84,15 @@ extern "C" fn kstart() {
/// The entry to Rust, all things must be initialized
unsafe extern "C" fn start(args_ptr: *const KernelArgs, stack_end: usize) -> ! {
unsafe {
// EARLY CANARY: write 'R' to COM1 before any kernel init.
// This proves the serial hardware works and the kernel reached Rust entry.
// If this character appears but "Redox OS starting..." does not,
// the hang is in args_ptr.read(), serial::init(), or graphical_debug::init().
#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
{
core::arch::asm!("out dx, al", in("dx") 0x3F8u16, in("al") b'R', options(nostack, preserves_flags));
}
let bootstrap = {
let args = args_ptr.read();
@@ -93,15 +102,31 @@ unsafe extern "C" fn start(args_ptr: *const KernelArgs, stack_end: usize) -> ! {
// Set up graphical debug
graphical_debug::init(args.env());
// SECOND CANARY: write 'S' to COM1 after serial init.
// If 'R' appears but 'S' does not, the hang is in serial::init() or graphical_debug::init().
#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
{
core::arch::asm!("out dx, al", in("dx") 0x3F8u16, in("al") b'S', options(nostack, preserves_flags));
}
info!("Redox OS starting...");
args.print();
#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
{ core::arch::asm!("out dx, al", in("dx") 0x3F8u16, in("al") b'1', options(nostack, preserves_flags)); }
// Set up GDT
gdt::init_bsp(stack_end);
#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
{ core::arch::asm!("out dx, al", in("dx") 0x3F8u16, in("al") b'2', options(nostack, preserves_flags)); }
// Set up IDT
idt::init_bsp();
#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
{ core::arch::asm!("out dx, al", in("dx") 0x3F8u16, in("al") b'3', options(nostack, preserves_flags)); }
// Initialize RMM
#[cfg(target_arch = "x86")]
let mut bump_allocator =
@@ -109,6 +134,9 @@ unsafe extern "C" fn start(args_ptr: *const KernelArgs, stack_end: usize) -> ! {
#[cfg(target_arch = "x86_64")]
let mut bump_allocator = crate::startup::memory::init(&args, Some(0x100000), None);
#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
{ core::arch::asm!("out dx, al", in("dx") 0x3F8u16, in("al") b'4', options(nostack, preserves_flags)); }
// Initialize paging
paging::init();
@@ -135,6 +163,9 @@ unsafe extern "C" fn start(args_ptr: *const KernelArgs, stack_end: usize) -> ! {
// Activate memory logging
crate::log::init();
#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
{ core::arch::asm!("out dx, al", in("dx") 0x3F8u16, in("al") b'6', options(nostack, preserves_flags)); }
// Initialize miscellaneous processor features
#[cfg(target_arch = "x86_64")]
crate::arch::misc::init(LogicalCpuId::BSP);
@@ -142,6 +173,9 @@ unsafe extern "C" fn start(args_ptr: *const KernelArgs, stack_end: usize) -> ! {
// Initialize devices
device::init();
#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
{ core::arch::asm!("out dx, al", in("dx") 0x3F8u16, in("al") b'7', options(nostack, preserves_flags)); }
// Read ACPI tables, starts APs
if cfg!(feature = "acpi") {
crate::acpi::init_after_mem(args.acpi_rsdp());