microblaze: Support word copying in copy_tofrom_user

Word copying is used only for aligned addresses.
Here is space for improving to use any better copying technique.
Look at memcpy implementation.

Signed-off-by: Michal Simek <monstr@monstr.eu>

1 files changed, 25 insertions, 14 deletions

diff --git a/arch/microblaze/lib/uaccess_old.S b/arch/microblaze/lib/uaccess_old.S
index b327524a8032..5810cec54a7a 100644
--- a/arch/microblaze/lib/uaccess_old.S
+++ b/arch/microblaze/lib/uaccess_old.S
@@ -53,7 +53,6 @@ __strncpy_user:
         nop
         .size   __strncpy_user, . - __strncpy_user
 
-
         .section        .fixup, "ax"
         .align  2
 4:
@@ -95,7 +94,6 @@ __strnlen_user:
         nop
         .size   __strnlen_user, . - __strnlen_user
 
-
         .section        .fixup,"ax"
 4:
         brid    3b
@@ -121,21 +119,34 @@ __copy_tofrom_user:
          * r7, r3 - count
          * r4 - tempval
          */
-        addik   r3,r7,0
-        beqi    r3,3f
-1:
-        lbu     r4,r6,r0
-        addik   r6,r6,1
-2:
-        sb      r4,r5,r0
-        addik   r3,r3,-1
-        bneid   r3,1b
-        addik   r5,r5,1         /* delay slot */
+        beqid   r7, 3f /* zero size is not likely */
+        andi    r3, r7, 0x3 /* filter add count */
+        bneid   r3, 4f /* if is odd value then byte copying */
+        or      r3, r5, r6 /* find if is any to/from unaligned */
+        andi    r3, r3, 0x3 /* mask unaligned */
+        bneid   r3, 1f /* it is unaligned -> then jump */
+        or      r3, r0, r0
+
+/* at least one 4 byte copy */
+5:      lw      r4, r6, r3
+6:      sw      r4, r5, r3
+        addik   r7, r7, -4
+        bneid   r7, 5b
+        addik   r3, r3, 4
+        addik   r3, r7, 0
+        rtsd    r15, 8
+        nop
+4:      or      r3, r0, r0
+1:      lbu     r4,r6,r3
+2:      sb      r4,r5,r3
+        addik   r7,r7,-1
+        bneid   r7,1b
+        addik   r3,r3,1         /* delay slot */
 3:
+        addik   r3,r7,0
         rtsd    r15,8
         nop
         .size   __copy_tofrom_user, . - __copy_tofrom_user
 
-
         .section        __ex_table,"a"
-        .word   1b,3b,2b,3b
+        .word   1b,3b,2b,3b,5b,3b,6b,3b