From 799a23014a32d759e3099f7fb5315c5b9dcc3ec9 Mon Sep 17 00:00:00 2001
From: Max Wash <mbswash@gmail.com>
Date: Thu, 2 Feb 2023 21:00:40 +0000
Subject: [PATCH] sandbox: add locking primitives

---
 sandbox/Makefile                    |  2 +-
 sandbox/locks/include/socks/locks.h | 11 +++++++++++
 sandbox/locks/spinlock.c            | 14 ++++++++++++++
 3 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 sandbox/locks/include/socks/locks.h
 create mode 100644 sandbox/locks/spinlock.c

diff --git a/sandbox/Makefile b/sandbox/Makefile
index 7a65408..81a5206 100644
--- a/sandbox/Makefile
+++ b/sandbox/Makefile
@@ -6,7 +6,7 @@ BUILD_DIR := $(SANDBOX_BASE_DIR)/../build/sandbox
 
 include $(SANDBOX_BASE_DIR)/../tools/make/gcc-host.mk
 EXEC_NAME := sandbox
-DIR_LIST := memblock vm base queue btree util
+DIR_LIST := memblock vm base queue btree util locks
 INCLUDE_DIRS := $(foreach dir,$(DIR_LIST),-I$(dir)/include)
 SRC := $(foreach dir,$(DIR_LIST),$(wildcard $(dir)/*.c))
 OBJ := $(addprefix $(BUILD_DIR)/,$(SRC:.c=.o))
diff --git a/sandbox/locks/include/socks/locks.h b/sandbox/locks/include/socks/locks.h
new file mode 100644
index 0000000..9b07aae
--- /dev/null
+++ b/sandbox/locks/include/socks/locks.h
@@ -0,0 +1,11 @@
+#ifndef SOCKS_LOCKS_H_
+#define SOCKS_LOCKS_H_
+
+typedef int __attribute__((aligned(8))) spin_lock_t;
+
+#define SPIN_LOCK_INIT ((spin_lock_t)0)
+
+extern void spin_lock_irqsave(spin_lock_t *lck, unsigned long *flags);
+extern void spin_unlock_irqrestore(spin_lock_t *lck, unsigned long flags);
+
+#endif
diff --git a/sandbox/locks/spinlock.c b/sandbox/locks/spinlock.c
new file mode 100644
index 0000000..0e247d9
--- /dev/null
+++ b/sandbox/locks/spinlock.c
@@ -0,0 +1,14 @@
+#include <socks/locks.h>
+
+void spin_lock_irqsave(spin_lock_t *lck, unsigned long *flags)
+{
+	while (!__sync_bool_compare_and_swap(lck, 0, 1)) {
+		/* pause */
+	}
+}
+
+void spin_unlock_irqrestore(spin_lock_t *lck, unsigned long flags)
+{
+    __sync_lock_release(lck);
+}
+