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Commit ebe21125 authored by Michal Simek's avatar Michal Simek
Browse files

microblaze: Add loop unrolling for PAGE in copy_tofrom_user 



Increase performance by loop unrolling.

Signed-off-by: default avatarMichal Simek <monstr@monstr.eu>
parent 782d491f

arch/microblaze/lib/uaccess_old.S

+84 −0
Original line number Diff line number Diff line
@@ -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