1 files changed, 93 insertions, 0 deletions
diff --git a/extras/mini-os/include/x86/arch_spinlock.h b/extras/mini-os/include/x86/arch_spinlock.h
new file mode 100644
index 0000000000..a181ed3c92
--- /dev/null
+++ b/extras/mini-os/include/x86/arch_spinlock.h
@@ -0,0 +1,93 @@
+
+
+#ifndef __ARCH_ASM_SPINLOCK_H
+#define __ARCH_ASM_SPINLOCK_H
+
+#include <lib.h>
+
+
+#define ARCH_SPIN_LOCK_UNLOCKED (spinlock_t) { 1 }
+
+/*
+ * Simple spin lock operations.  There are two variants, one clears IRQ's
+ * on the local processor, one does not.
+ *
+ * We make no fairness assumptions. They have a cost.
+ */
+
+#define arch_spin_is_locked(x)	(*(volatile signed char *)(&(x)->slock) <= 0)
+#define spin_unlock_wait(x)	do { barrier(); } while(spin_is_locked(x))
+
+#define spin_lock_string \
+        "1:\n" \
+	LOCK \
+	"decb %0\n\t" \
+	"jns 3f\n" \
+	"2:\t" \
+	"rep;nop\n\t" \
+	"cmpb $0,%0\n\t" \
+	"jle 2b\n\t" \
+	"jmp 1b\n" \
+	"3:\n\t"
+
+#define spin_lock_string_flags \
+        "1:\n" \
+	LOCK \
+	"decb %0\n\t" \
+	"jns 4f\n\t" \
+	"2:\t" \
+	"testl $0x200, %1\n\t" \
+	"jz 3f\n\t" \
+	"#sti\n\t" \
+	"3:\t" \
+	"rep;nop\n\t" \
+	"cmpb $0, %0\n\t" \
+	"jle 3b\n\t" \
+	"#cli\n\t" \
+	"jmp 1b\n" \
+	"4:\n\t"
+
+/*
+ * This works. Despite all the confusion.
+ * (except on PPro SMP or if we are using OOSTORE)
+ * (PPro errata 66, 92)
+ */
+
+#define spin_unlock_string \
+	"xchgb %b0, %1" \
+		:"=q" (oldval), "=m" (lock->slock) \
+		:"0" (oldval) : "memory"
+
+static inline void _raw_spin_unlock(spinlock_t *lock)
+{
+	char oldval = 1;
+	__asm__ __volatile__(
+		spin_unlock_string
+	);
+}
+
+static inline int _raw_spin_trylock(spinlock_t *lock)
+{
+	char oldval;
+	__asm__ __volatile__(
+		"xchgb %b0,%1\n"
+		:"=q" (oldval), "=m" (lock->slock)
+		:"0" (0) : "memory");
+	return oldval > 0;
+}
+
+static inline void _raw_spin_lock(spinlock_t *lock)
+{
+	__asm__ __volatile__(
+		spin_lock_string
+		:"=m" (lock->slock) : : "memory");
+}
+
+static inline void _raw_spin_lock_flags (spinlock_t *lock, unsigned long flags)
+{
+	__asm__ __volatile__(
+		spin_lock_string_flags
+		:"=m" (lock->slock) : "r" (flags) : "memory");
+}
+
+#endif