diff --git a/arch/x86/kernel/processor.c b/arch/x86/kernel/processor.c
index f2237f17..2b1c84bf 100644
--- a/arch/x86/kernel/processor.c
+++ b/arch/x86/kernel/processor.c
@@ -23,16 +23,10 @@
 #include <metalsvm/processor.h>
 #ifdef CONFIG_ROCKCREEK
 #include <asm/RCCE_lib.h>
-#else
-/* disable optimization for the following functions */
-uint32_t detect_cpu_frequency(void) __attribute__((optimize(0)));
 #endif
 
 static uint32_t cpu_freq = 0;
 
-/* disable optimization for the following functions */
-void udelay(uint32_t usecs) __attribute__((optimize(0)));
-
 uint32_t detect_cpu_frequency(void)
 {
 #ifdef CONFIG_ROCKCREEK
@@ -53,12 +47,14 @@ uint32_t detect_cpu_frequency(void)
 
 	/* wait for the next time slice */
 	while((ticks = get_clock_tick()) - old == 0)
-		;
+		HALT;
 
+	rmb();
 	start = rdtsc();
 	/* wait a second to determine the frequency */
 	while(get_clock_tick() - ticks < TIMER_FREQ)
-		;
+		HALT;
+	rmb();
 	end = rdtsc();
 
 	diff = end > start ? end - start : start - end;
@@ -82,6 +78,7 @@ void udelay(uint32_t usecs)
 	uint64_t deadline = get_cpu_frequency() * usecs;
 
 	do {
+		rmb();
 		end = rdtsc();
 		diff = end > start ? end - start : start - end;
 	} while(diff < deadline);