--- /dev/null
+/*
+ * linux/include/asm-i386/tsc.h
+ *
+ * i386 TSC related functions
+ */
+#ifndef _ARCH_x86_64_TSC_H
+#define _ARCH_x86_64_TSC_H
+
+#include <lwk/types.h>
+#include <arch/processor.h>
+
+typedef uint64_t cycles_t;
+
+/**
+ * Returns the current value of the CPU's cycle counter.
+ *
+ * NOTE: This is not serializing. It doesn't necessarily wait for previous
+ * instructions to complete before reading the cycle counter. Also,
+ * subsequent instructions could potentially begin execution before
+ * the cycle counter is read.
+ */
+static __always_inline cycles_t
+get_cycles(void)
+{
+ cycles_t ret = 0;
+ rdtscll(ret);
+ return ret;
+}
+
+/**
+ * This is a synchronizing version of get_cycles(). It ensures that all
+ * previous instructions have completed before reading the cycle counter.
+ */
+static __always_inline cycles_t
+get_cycles_sync(void)
+{
+ sync_core();
+ return get_cycles();
+}
+
+#endif
