microblaze: Support word copying in copy_tofrom_user
Michal Simek [Mon, 22 Mar 2010 19:31:26 +0000 (20:31 +0100)]
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>

arch/microblaze/lib/uaccess_old.S

index b327524..5810cec 100644 (file)
@@ -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