Initial Commit

src/mp/spinlock.c

@@ -0,0 +1,26 @@
+#include "spinlock.h"
+
+void spinlock_init(spinlock_t *lock) {
+    atomic_flag_clear(&lock->flag);
+}
+
+void spinlock_acquire_or_wait(spinlock_t *lock) {
+    while (atomic_flag_test_and_set_explicit(&lock->flag, memory_order_acquire))
+        asm volatile("pause" ::: "memory");
+}
+
+void spinlock_drop(spinlock_t *lock) {
+    atomic_flag_clear_explicit(&lock->flag, memory_order_release);
+}
+
+void spinlock_acquire_irqsave(spinlock_t *lock, uint64_t *flags) {
+    uint64_t f;
+    asm volatile("pushfq; pop %0; cli" : "=r"(f) :: "memory");
+    *flags = f;
+    spinlock_acquire_or_wait(lock);
+}
+
+void spinlock_release_irqrestore(spinlock_t *lock, uint64_t flags) {
+    spinlock_drop(lock);
+    asm volatile("push %0; popfq" :: "r"(flags) : "memory", "cc");
+}

src/mp/spinlock.h

@@ -0,0 +1,17 @@
+#pragma once
+#include <stdatomic.h>
+#include <stdint.h>
+
+typedef struct {
+    atomic_flag flag;
+} spinlock_t;
+
+#define SPINLOCK_INIT ((spinlock_t){ .flag = ATOMIC_FLAG_INIT })
+
+void spinlock_init(spinlock_t *lock);
+void spinlock_acquire_or_wait(spinlock_t *lock);
+void spinlock_drop(spinlock_t *lock);
+
+// Old IRQ-safe API still available for compatibility
+void spinlock_acquire_irqsave(spinlock_t *lock, uint64_t *flags);
+void spinlock_release_irqrestore(spinlock_t *lock, uint64_t flags);