microblaze: Add loop unrolling for PAGE in copy_tofrom_user

Increase performance by loop unrolling.

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

diff --git a/arch/microblaze/lib/uaccess_old.S b/arch/microblaze/lib/uaccess_old.S
index d09f2dce648dcebf1e925f9e8c982af85b771ecc..142492ec270fbef323a7e8c37993bf4f38b140f1 100644 (file)
--- a/arch/microblaze/lib/uaccess_old.S
+++ b/arch/microblaze/lib/uaccess_old.S
@@ -10,6 +10,7 @@
 
 #include <linux/errno.h>
 #include <linux/linkage.h>
+#include <asm/page.h>
 
 /*
  * int __strncpy_user(char *to, char *from, int len);
@@ -102,6 +103,49 @@ __strnlen_user:
        .section        __ex_table,"a"
        .word   1b,4b
 
+/* Loop unrolling for __copy_tofrom_user */
+#define COPY(offset)   \
+1:     lwi     r4 , r6, 0x0000 + offset;       \
+2:     lwi     r19, r6, 0x0004 + offset;       \
+3:     lwi     r20, r6, 0x0008 + offset;       \
+4:     lwi     r21, r6, 0x000C + offset;       \
+5:     lwi     r22, r6, 0x0010 + offset;       \
+6:     lwi     r23, r6, 0x0014 + offset;       \
+7:     lwi     r24, r6, 0x0018 + offset;       \
+8:     lwi     r25, r6, 0x001C + offset;       \
+9:     swi     r4 , r5, 0x0000 + offset;       \
+10:    swi     r19, r5, 0x0004 + offset;       \
+11:    swi     r20, r5, 0x0008 + offset;       \
+12:    swi     r21, r5, 0x000C + offset;       \
+13:    swi     r22, r5, 0x0010 + offset;       \
+14:    swi     r23, r5, 0x0014 + offset;       \
+15:    swi     r24, r5, 0x0018 + offset;       \
+16:    swi     r25, r5, 0x001C + offset;       \
+       .section __ex_table,"a";                \
+       .word   1b, 0f;                         \
+       .word   2b, 0f;                         \
+       .word   3b, 0f;                         \
+       .word   4b, 0f;                         \
+       .word   5b, 0f;                         \
+       .word   6b, 0f;                         \
+       .word   7b, 0f;                         \
+       .word   8b, 0f;                         \
+       .word   9b, 0f;                         \
+       .word   10b, 0f;                        \
+       .word   11b, 0f;                        \
+       .word   12b, 0f;                        \
+       .word   13b, 0f;                        \
+       .word   14b, 0f;                        \
+       .word   15b, 0f;                        \
+       .word   16b, 0f;                        \
+       .text
+
+#define COPY_80(offset)        \
+       COPY(0x00 + offset);\
+       COPY(0x20 + offset);\
+       COPY(0x40 + offset);\
+       COPY(0x60 + offset);
+
 /*
  * int __copy_tofrom_user(char *to, char *from, int len)
  * Return:
@@ -126,6 +170,10 @@ __copy_tofrom_user:
        bneid   r3, bu1 /* if r3 is not zero then byte copying */
        or      r3, r0, r0
 
+       rsubi   r3, r7, PAGE_SIZE /* detect PAGE_SIZE */
+       beqid   r3, page;
+       or      r3, r0, r0
+
 w1:    lw      r4, r6, r3 /* at least one 4 byte copy */
 w2:    sw      r4, r5, r3
        addik   r7, r7, -4
@@ -140,6 +188,42 @@ w2:        sw      r4, r5, r3
        .word   w2, 0f;
        .text
 
+.align 4 /* Alignment is important to keep icache happy */
+page:  /* Create room on stack and save registers for storign values */
+       addik   r1, r1, -32
+       swi     r19, r1, 4
+       swi     r20, r1, 8
+       swi     r21, r1, 12
+       swi     r22, r1, 16
+       swi     r23, r1, 20
+       swi     r24, r1, 24
+       swi     r25, r1, 28
+loop:  /* r4, r19, r20, r21, r22, r23, r24, r25 are used for storing values */
+       /* Loop unrolling to get performance boost */
+       COPY_80(0x000);
+       COPY_80(0x080);
+       COPY_80(0x100);
+       COPY_80(0x180);
+       /* copy loop */
+       addik   r6, r6, 0x200
+       addik   r7, r7, -0x200
+       bneid   r7, loop
+       addik   r5, r5, 0x200
+       /* Restore register content */
+       lwi     r19, r1, 4
+       lwi     r20, r1, 8
+       lwi     r21, r1, 12
+       lwi     r22, r1, 16
+       lwi     r23, r1, 20
+       lwi     r24, r1, 24
+       lwi     r25, r1, 28
+       addik   r1, r1, 32
+       /* return back */
+       addik   r3, r7, 0
+       rtsd    r15, 8
+       nop
+
+.align 4 /* Alignment is important to keep icache happy */
 bu1:   lbu     r4,r6,r3
 bu2:   sb      r4,r5,r3
        addik   r7,r7,-1