1 files changed, 9 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 99550d3615c4..96e31de89b43 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -409,7 +409,7 @@ 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;
 
@@ -419,6 +419,14 @@ 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);