1 files changed, 48 insertions, 0 deletions
diff --git a/kernel/atomic.h b/kernel/atomic.h
new file mode 100644
index 0000000..a5b892f
--- /dev/null
+++ b/kernel/atomic.h
@@ -0,0 +1,48 @@
+#pragma once
+
+#include "kernel/lib.h"
+
+enum MemoryOrdering
+{
+    MEM_RELAXED = 0,
+    MEM_ACQUIRE = 1,
+    MEM_RELEASE = 2,
+    MEM_ACQ_REL = 3,
+};
+
+static inline uint32_t atomic_load(volatile uint32_t* v, enum MemoryOrdering o)
+{
+    uint32_t v2;
+    switch (o)
+    {
+        case MEM_RELAXED: __asm__ volatile("lr.w      %0, (%1)" : "=r"(v2) : "r"(v)); break;
+        case MEM_ACQUIRE: __asm__ volatile("lr.w.aq   %0, (%1)" : "=r"(v2) : "r"(v)); break;
+        case MEM_RELEASE: __asm__ volatile("lr.w.rl   %0, (%1)" : "=r"(v2) : "r"(v)); break;
+        case MEM_ACQ_REL: __asm__ volatile("lr.w.aqrl %0, (%1)" : "=r"(v2) : "r"(v)); break;
+    }
+    return v2;
+}
+
+static inline uint32_t atomic_fetch_add(volatile uint32_t* v, uint32_t a, enum MemoryOrdering o)
+{
+    uint32_t v2;
+    switch (o)
+    {
+        case MEM_RELAXED: __asm__ volatile("amoadd.w      %0, %1, (%2)" : "=r"(v2) : "r"(a), "r"(v)); break;
+        case MEM_ACQUIRE: __asm__ volatile("amoadd.w.aq   %0, %1, (%2)" : "=r"(v2) : "r"(a), "r"(v)); break;
+        case MEM_RELEASE: __asm__ volatile("amoadd.w.rl   %0, %1, (%2)" : "=r"(v2) : "r"(a), "r"(v)); break;
+        case MEM_ACQ_REL: __asm__ volatile("amoadd.w.aqrl %0, %1, (%2)" : "=r"(v2) : "r"(a), "r"(v)); break;
+    }
+    return v2;
+}
+
+static inline void atomic_fence(enum MemoryOrdering o)
+{
+    switch (o)
+    {
+        case MEM_RELAXED: __asm__ volatile(""); break;
+        case MEM_ACQUIRE: __asm__ volatile("fence r,rw"); break;
+        case MEM_RELEASE: __asm__ volatile("fence rw,w"); break;
+        case MEM_ACQ_REL: __asm__ volatile("fence.tso"); break;
+    }
+}