1 files changed, 46 insertions, 0 deletions

diff --git a/rsdos/src/main.rs b/rsdos/src/main.rs
index a528810..7ca031c 100644
--- a/rsdos/src/main.rs
+++ b/rsdos/src/main.rs
@@ -8,9 +8,44 @@ use rsnix::uefi::*;
 // ---------------------------------------------------------------------------
 // Panic handler
 // ---------------------------------------------------------------------------
+
+/// Small fmt::Write over a byte slice (no allocation, bounded).
+struct PanicBuf<'a> {
+    b: &'a mut [u8],
+    n: usize,
+}
+
+impl core::fmt::Write for PanicBuf<'_> {
+    fn write_str(&mut self, s: &str) -> core::fmt::Result {
+        let m = s.len().min(self.b.len() - self.n);
+        self.b[self.n..self.n + m].copy_from_slice(&s.as_bytes()[..m]);
+        self.n += m;
+        Ok(())
+    }
+}
+
 #[panic_handler]
 fn panic(info: &PanicInfo) -> ! {
     use core::fmt::Write;
+
+    // A background task (id >= 2) panicked: die gracefully — log it,
+    // mark the task done, switch away.  The shell keeps running and
+    // `jobs` shows the corpse.  Panics in the shell, idle, ISR context,
+    // or before the scheduler exists still halt the whole system.
+    if rsnix::sched::is_ready() && !rsnix::sched::in_isr() && rsnix::sched::current() >= 2 {
+        let mut buf = [0u8; 192];
+        let n = {
+            let mut w = PanicBuf { b: &mut buf, n: 0 };
+            let _ = write!(&mut w, "{}", info.message());
+            if let Some(loc) = info.location() {
+                let _ = write!(&mut w, " at {}:{}", loc.file(), loc.line());
+            }
+            w.n
+        };
+        let msg = core::str::from_utf8(&buf[..n]).unwrap_or("task panic");
+        rsnix::sched::abort_current(msg);
+    }
+
     rsnix::serial::write_str("\r\n*** PANIC ***\r\n");
     let _ = write!(&mut rsnix::serial::SerialWriter, "{}\r\n", info.message());
     if let Some(loc) = info.location() {
@@ -114,6 +149,11 @@ pub unsafe extern "efiapi" fn efi_main(image_handle: Handle, system_table: *mut
     rsnix::serial_println!("serial: COM1 115200 8N1");
     rsnix::ps2::init();
     rsnix::serial_println!("ps2: keyboard initialized");
+    if rsnix::gdt::init() {
+        rsnix::serial_println!("gdt: own GDT + TSS (IST: page-fault/double-fault)");
+    } else {
+        rsnix::serial_println!("gdt: kept UEFI GDT (IST fault stacks off)");
+    }
     rsnix::interrupts::init();
     rsnix::serial_println!("intr: IDT loaded, PIC remapped, timer ~100 Hz");
 
@@ -151,6 +191,12 @@ pub unsafe extern "efiapi" fn efi_main(image_handle: Handle, system_table: *mut
         rsnix::serial_println!("pg: self-test FAILED");
     }
 
+    // Scheduler init needs the page allocator (idle task's stack + guard
+    // page) and the adopted page tables, so it runs after the memory
+    // subsystem is fully up.  The tick (interrupts::init) is already
+    // live, which is what `sleep`/wake scheduling depends on.
+    rsnix::sched::init();
+
     let t = rsnix::rtc::now();
     rsnix::serial_println!(
         "rtc: {}-{:02}-{:02} {:02}:{:02}:{:02}",