CheckP: smp support

src/sys/work_queue.c

@@ -0,0 +1,62 @@
+// Copyright (c) 2023-2026 Chris (boreddevnl)
+// This software is released under the GNU General Public License v3.0. See LICENSE file for details.
+// This header needs to maintain in any file it is present in, as per the GPL license terms.
+#include "work_queue.h"
+#include "spinlock.h"
+
+extern void serial_write(const char *str);
+
+#define WORK_QUEUE_SIZE 64
+
+static work_item_t work_queue[WORK_QUEUE_SIZE];
+static volatile int wq_head = 0;
+static volatile int wq_tail = 0;
+static spinlock_t wq_lock = SPINLOCK_INIT;
+
+void work_queue_submit(work_fn_t fn, void *arg) {
+    if (!fn) return;
+
+    uint64_t flags = spinlock_acquire_irqsave(&wq_lock);
+    int next_tail = (wq_tail + 1) % WORK_QUEUE_SIZE;
+    if (next_tail == wq_head) {
+        // Queue full — drop the work item
+        spinlock_release_irqrestore(&wq_lock, flags);
+        return;
+    }
+    work_queue[wq_tail].fn = fn;
+    work_queue[wq_tail].arg = arg;
+    wq_tail = next_tail;
+    spinlock_release_irqrestore(&wq_lock, flags);
+}
+
+bool work_queue_drain_one(void) {
+    uint64_t flags = spinlock_acquire_irqsave(&wq_lock);
+    if (wq_head == wq_tail) {
+        spinlock_release_irqrestore(&wq_lock, flags);
+        return false;
+    }
+    work_item_t item = work_queue[wq_head];
+    wq_head = (wq_head + 1) % WORK_QUEUE_SIZE;
+    spinlock_release_irqrestore(&wq_lock, flags);
+
+    // Execute outside the lock
+    if (item.fn) {
+        item.fn(item.arg);
+    }
+    return true;
+}
+
+void work_queue_drain_loop(void) {
+    while (1) {
+        // Try to drain all pending work
+        while (work_queue_drain_one()) {
+            // Keep draining
+        }
+        
+        // No work — halt the CPU until an interrupt wakes us.
+        // With legacy PIC, APs don't receive timer interrupts, so they'll
+        // sleep until an IPI is sent (e.g., when work is submitted).
+        // This is ideal: APs use 0% CPU when idle.
+        asm volatile("sti; hlt; cli");
+    }
+}