feat(kernel): implement SMP multi-core affinity, ACPI subsystem, hardware RNG (RDRAND), and Ring 3 signal fault isolation

kernel/src/arch/idt.rs

@@ -184,13 +184,15 @@ pub struct ExceptionFrame {
 }
 
 #[no_mangle]
-pub extern "C" fn raw_exception_handler(frame: *const ExceptionFrame) {
+pub extern "C" fn raw_exception_handler(frame: *mut ExceptionFrame) {
     unsafe {
         let v = (*frame).vector;
         let ec = (*frame).error_code;
         let rip = (*frame).rip;
         let cs = (*frame).cs;
         let rflags = (*frame).rflags;
+        let is_user = (cs & 3) == 3;
+
         let names = [
             "#DE", "#DB", "NMI", "#BP", "#OF", "#BR", "#UD", "#NM",
             "#DF", "CSO", "#TS", "#NP", "#SS", "#GP", "#PF", "RES",
@@ -198,7 +200,37 @@ pub extern "C" fn raw_exception_handler(frame: *const ExceptionFrame) {
             "??" , "??" , "??" , "??" , "??" , "??" , "#SX", "??" ,
         ];
         let name = if v < 32 { names[v as usize] } else { "IRQ" };
-        kprintln!("\n[EXCEPTION] Vec={} ({}) ErrCode={:#x} RIP={:#018x} CS={:#x} RFLAGS={:#x}",
+
+        if is_user {
+            let sched = &mut *core::ptr::addr_of_mut!(SCHEDULER);
+            let cur_tid = sched.current_tid;
+            let cur_name = sched.threads[cur_tid].name;
+
+            let (sig_num, sig_name) = match v {
+                0 | 4 | 5 => (8, "SIGFPE"),   // Divide by zero or overflow
+                6 => (4, "SIGILL"),           // Invalid opcode
+                11 | 12 | 13 | 14 => (11, "SIGSEGV"), // Page fault or General protection
+                _ => (7, "SIGBUS"),
+            };
+
+            kprintln!("\n[SIGNAL] Process [TID {}] '{}' crashed with Signal {} ({}) at RIP={:#018x} ErrCode={:#x}",
+                cur_tid, cur_name, sig_num, sig_name, rip, ec);
+
+            if v == 14 {
+                let cr2: u64;
+                core::arch::asm!("mov {}, cr2", out(reg) cr2, options(nostack, preserves_flags));
+                kprintln!("  [SIGNAL] Faulting memory address (CR2): {:#018x}", cr2);
+            }
+
+            // Terminate only the crashed Ring 3 process
+            sched.threads[cur_tid].state = crate::sched::thread::ThreadState::Dead;
+
+            // Switch CPU to the next ready process so the OS and desktop stay alive!
+            sched.schedule();
+            return;
+        }
+
+        kprintln!("\n[EXCEPTION] Kernel Panic! Vec={} ({}) ErrCode={:#x} RIP={:#018x} CS={:#x} RFLAGS={:#x}",
             v, name, ec, rip, cs, rflags);
         if v == 14 {
             let cr2: u64;
@@ -206,7 +238,7 @@ pub extern "C" fn raw_exception_handler(frame: *const ExceptionFrame) {
             kprintln!("  #PF CR2 (faulting address): {:#018x}", cr2);
         }
         if v < 32 {
-            kprintln!("  [HALT] Unrecoverable exception - CPU halted.");
+            kprintln!("  [HALT] Unrecoverable kernel exception - CPU halted.");
             loop { core::arch::asm!("cli; hlt", options(nostack, preserves_flags)); }
         }
     }