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microblaze: Add loop unrolling for PAGE in copy_tofrom_user 

Increase performance by loop unrolling.

Signed-off-by: Michal Simek <monstr@monstr.eu>
This commit is contained in:
Michal Simek 2011-06-10 10:49:08 +02:00
parent 782d491fc2
commit ebe211254b
1 changed files with 84 additions and 0 deletions
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84
arch/microblaze/lib/uaccess_old.S
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@ -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