diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index bccc81b..f49a05f 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -420,7 +420,7 @@ static inline int set_dabr(struct arch_hw_breakpoint *brk)
 
 static inline int set_dawr(struct arch_hw_breakpoint *brk)
 {
-	unsigned long dawr, dawrx;
+	unsigned long dawr, dawrx, mrd;
 
 	dawr = brk->address;
 
@@ -430,6 +430,14 @@ static inline int set_dawr(struct arch_hw_breakpoint *brk)
 		                   << (63 - 59); //* translate */
 	dawrx |= (brk->type & (HW_BRK_TYPE_PRIV_ALL)) \
 		                   >> 3; //* PRIM bits */
+	/* dawr length is stored in field MDR bits 48:53.  Matches range in
+	   doublewords (64 bits) baised by -1 eg. 0b000000=1DW and
+	   0b111111=64DW.
+	   brk->len is in bytes.
+	   This aligns up to double word size, shifts and does the bias.
+	*/
+	mrd = ((brk->len + 7) >> 3) - 1;
+	dawrx |= (mrd & 0x3f) << (63 - 53);
 
 	if (ppc_md.set_dawr)
 		return ppc_md.set_dawr(dawr, dawrx);