diff --git a/arch/arm64/mm/proc-macros.S b/arch/arm64/mm/proc-macros.S
index 8957b82..005d29e 100644
--- a/arch/arm64/mm/proc-macros.S
+++ b/arch/arm64/mm/proc-macros.S
@@ -38,8 +38,7 @@
  */
 	.macro	dcache_line_size, reg, tmp
 	mrs	\tmp, ctr_el0			// read CTR
-	lsr	\tmp, \tmp, #16
-	and	\tmp, \tmp, #0xf		// cache line size encoding
+	ubfm	\tmp, \tmp, #16, #19		// cache line size encoding
 	mov	\reg, #4			// bytes per word
 	lsl	\reg, \reg, \tmp		// actual cache line size
 	.endm