diff --git a/arch/riscv/lib/delay.c b/arch/riscv/lib/delay.c
index dce8ae24c6d33b4ca3ebd0c19c3650f1ce890bde..ee6853c1e341c5455c9440cdb1cc585351b5541f 100644
--- a/arch/riscv/lib/delay.c
+++ b/arch/riscv/lib/delay.c
@@ -88,7 +88,7 @@ EXPORT_SYMBOL(__delay);
 
 void udelay(unsigned long usecs)
 {
-	unsigned long ucycles = usecs * lpj_fine * UDELAY_MULT;
+	u64 ucycles = (u64)usecs * lpj_fine * UDELAY_MULT;
 
 	if (unlikely(usecs > MAX_UDELAY_US)) {
 		__delay((u64)usecs * riscv_timebase / 1000000ULL);