[linux-2.6-block.git] / arch / powerpc / lib / string_64.S

/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Copyright (C) IBM Corporation, 2012
 *
 * Author: Anton Blanchard <anton@au.ibm.com>
 */

#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>

	.section	".toc","aw"
PPC64_CACHES:
	.tc		ppc64_caches[TC],ppc64_caches
	.section	".text"

/**
 * __clear_user: - Zero a block of memory in user space, with less checking.
 * @to:   Destination address, in user space.
 * @n:    Number of bytes to zero.
 *
 * Zero a block of memory in user space.  Caller must check
 * the specified block with access_ok() before calling this function.
 *
 * Returns number of bytes that could not be cleared.
 * On success, this will be zero.
 */

	.macro err1
100:
	.section __ex_table,"a"
	.align 3
	.llong 100b,.Ldo_err1
	.previous
	.endm

	.macro err2
200:
	.section __ex_table,"a"
	.align 3
	.llong 200b,.Ldo_err2
	.previous
	.endm

	.macro err3
300:
	.section __ex_table,"a"
	.align 3
	.llong 300b,.Ldo_err3
	.previous
	.endm

.Ldo_err1:
	mr	r3,r8

.Ldo_err2:
	mtctr	r4
1:
err3;	stb	r0,0(r3)
	addi	r3,r3,1
	addi	r4,r4,-1
	bdnz	1b

.Ldo_err3:
	mr	r3,r4
	blr

_GLOBAL_TOC(__clear_user)
	cmpdi	r4,32
	neg	r6,r3
	li	r0,0
	blt	.Lshort_clear
	mr	r8,r3
	mtocrf	0x01,r6
	clrldi	r6,r6,(64-3)

	/* Get the destination 8 byte aligned */
	bf	cr7*4+3,1f
err1;	stb	r0,0(r3)
	addi	r3,r3,1

1:	bf	cr7*4+2,2f
err1;	sth	r0,0(r3)
	addi	r3,r3,2

2:	bf	cr7*4+1,3f
err1;	stw	r0,0(r3)
	addi	r3,r3,4

3:	sub	r4,r4,r6

	cmpdi	r4,32
	cmpdi	cr1,r4,512
	blt	.Lshort_clear
	bgt	cr1,.Llong_clear

.Lmedium_clear:
	srdi	r6,r4,5
	mtctr	r6

	/* Do 32 byte chunks */
4:
err2;	std	r0,0(r3)
err2;	std	r0,8(r3)
err2;	std	r0,16(r3)
err2;	std	r0,24(r3)
	addi	r3,r3,32
	addi	r4,r4,-32
	bdnz	4b

.Lshort_clear:
	/* up to 31 bytes to go */
	cmpdi	r4,16
	blt	6f
err2;	std	r0,0(r3)
err2;	std	r0,8(r3)
	addi	r3,r3,16
	addi	r4,r4,-16

	/* Up to 15 bytes to go */
6:	mr	r8,r3
	clrldi	r4,r4,(64-4)
	mtocrf	0x01,r4
	bf	cr7*4+0,7f
err1;	std	r0,0(r3)
	addi	r3,r3,8

7:	bf	cr7*4+1,8f
err1;	stw	r0,0(r3)
	addi	r3,r3,4

8:	bf	cr7*4+2,9f
err1;	sth	r0,0(r3)
	addi	r3,r3,2

9:	bf	cr7*4+3,10f
err1;	stb	r0,0(r3)

10:	li	r3,0
	blr

.Llong_clear:
	ld	r5,PPC64_CACHES@toc(r2)

	bf	cr7*4+0,11f
err2;	std	r0,0(r3)
	addi	r3,r3,8
	addi	r4,r4,-8

	/* Destination is 16 byte aligned, need to get it cacheline aligned */
11:	lwz	r7,DCACHEL1LOGLINESIZE(r5)
	lwz	r9,DCACHEL1LINESIZE(r5)

	/*
	 * With worst case alignment the long clear loop takes a minimum
	 * of 1 byte less than 2 cachelines.
	 */
	sldi	r10,r9,2
	cmpd	r4,r10
	blt	.Lmedium_clear

	neg	r6,r3
	addi	r10,r9,-1
	and.	r5,r6,r10
	beq	13f

	srdi	r6,r5,4
	mtctr	r6
	mr	r8,r3
12:
err1;	std	r0,0(r3)
err1;	std	r0,8(r3)
	addi	r3,r3,16
	bdnz	12b

	sub	r4,r4,r5

13:	srd	r6,r4,r7
	mtctr	r6
	mr	r8,r3
14:
err1;	dcbz	r0,r3
	add	r3,r3,r9
	bdnz	14b

	and	r4,r4,r10

	cmpdi	r4,32
	blt	.Lshort_clear
	b	.Lmedium_clear
Commit	Line	Data
17968fbb AB	1	/*
	2	* This program is free software; you can redistribute it and/or modify
	3	* it under the terms of the GNU General Public License as published by
	4	* the Free Software Foundation; either version 2 of the License, or
	5	* (at your option) any later version.
	6	*
	7	* This program is distributed in the hope that it will be useful,
	8	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	9	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	10	* GNU General Public License for more details.
	11	*
	12	* You should have received a copy of the GNU General Public License
	13	* along with this program; if not, write to the Free Software
	14	* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	15	*
	16	* Copyright (C) IBM Corporation, 2012
	17	*
	18	* Author: Anton Blanchard <anton@au.ibm.com>
	19	*/
	20
	21	#include <asm/ppc_asm.h>
cf8fb553 AB	22	#include <asm/asm-offsets.h>
	23
	24	.section ".toc","aw"
	25	PPC64_CACHES:
	26	.tc ppc64_caches[TC],ppc64_caches
	27	.section ".text"
17968fbb AB	28
	29	/**
	30	* __clear_user: - Zero a block of memory in user space, with less checking.
	31	* @to: Destination address, in user space.
	32	* @n: Number of bytes to zero.
	33	*
	34	* Zero a block of memory in user space. Caller must check
	35	* the specified block with access_ok() before calling this function.
	36	*
	37	* Returns number of bytes that could not be cleared.
	38	* On success, this will be zero.
	39	*/
	40
	41	.macro err1
	42	100:
	43	.section __ex_table,"a"
	44	.align 3
	45	.llong 100b,.Ldo_err1
	46	.previous
	47	.endm
	48
	49	.macro err2
	50	200:
	51	.section __ex_table,"a"
	52	.align 3
	53	.llong 200b,.Ldo_err2
	54	.previous
	55	.endm
	56
	57	.macro err3
	58	300:
	59	.section __ex_table,"a"
	60	.align 3
	61	.llong 300b,.Ldo_err3
	62	.previous
	63	.endm
	64
	65	.Ldo_err1:
	66	mr r3,r8
	67
	68	.Ldo_err2:
	69	mtctr r4
	70	1:
	71	err3; stb r0,0(r3)
	72	addi r3,r3,1
	73	addi r4,r4,-1
	74	bdnz 1b
	75
	76	.Ldo_err3:
	77	mr r3,r4
	78	blr
	79
2ac7b016	80	_GLOBAL_TOC(__clear_user)
17968fbb AB	81	cmpdi r4,32
	82	neg r6,r3
	83	li r0,0
	84	blt .Lshort_clear
	85	mr r8,r3
	86	mtocrf 0x01,r6
	87	clrldi r6,r6,(64-3)
	88
	89	/* Get the destination 8 byte aligned */
	90	bf cr7*4+3,1f
	91	err1; stb r0,0(r3)
	92	addi r3,r3,1
	93
	94	1: bf cr7*4+2,2f
	95	err1; sth r0,0(r3)
	96	addi r3,r3,2
	97
	98	2: bf cr7*4+1,3f
	99	err1; stw r0,0(r3)
	100	addi r3,r3,4
	101
	102	3: sub r4,r4,r6
cf8fb553	103
17968fbb	104	cmpdi r4,32
cf8fb553	105	cmpdi cr1,r4,512
17968fbb	106	blt .Lshort_clear
cf8fb553 AB	107	bgt cr1,.Llong_clear
	108
	109	.Lmedium_clear:
	110	srdi r6,r4,5
17968fbb AB	111	mtctr r6
	112
	113	/* Do 32 byte chunks */
	114	4:
	115	err2; std r0,0(r3)
	116	err2; std r0,8(r3)
	117	err2; std r0,16(r3)
	118	err2; std r0,24(r3)
	119	addi r3,r3,32
	120	addi r4,r4,-32
	121	bdnz 4b
	122
	123	.Lshort_clear:
	124	/* up to 31 bytes to go */
	125	cmpdi r4,16
	126	blt 6f
	127	err2; std r0,0(r3)
	128	err2; std r0,8(r3)
	129	addi r3,r3,16
	130	addi r4,r4,-16
	131
	132	/* Up to 15 bytes to go */
	133	6: mr r8,r3
	134	clrldi r4,r4,(64-4)
	135	mtocrf 0x01,r4
	136	bf cr7*4+0,7f
	137	err1; std r0,0(r3)
	138	addi r3,r3,8
	139
	140	7: bf cr7*4+1,8f
	141	err1; stw r0,0(r3)
	142	addi r3,r3,4
	143
	144	8: bf cr7*4+2,9f
	145	err1; sth r0,0(r3)
	146	addi r3,r3,2
	147
	148	9: bf cr7*4+3,10f
	149	err1; stb r0,0(r3)
	150
	151	10: li r3,0
	152	blr
cf8fb553 AB	153
	154	.Llong_clear:
	155	ld r5,PPC64_CACHES@toc(r2)
	156
	157	bf cr7*4+0,11f
	158	err2; std r0,0(r3)
	159	addi r3,r3,8
	160	addi r4,r4,-8
	161
	162	/* Destination is 16 byte aligned, need to get it cacheline aligned */
	163	11: lwz r7,DCACHEL1LOGLINESIZE(r5)
	164	lwz r9,DCACHEL1LINESIZE(r5)
	165
	166	/*
	167	* With worst case alignment the long clear loop takes a minimum
	168	* of 1 byte less than 2 cachelines.
	169	*/
	170	sldi r10,r9,2
	171	cmpd r4,r10
	172	blt .Lmedium_clear
	173
	174	neg r6,r3
	175	addi r10,r9,-1
	176	and. r5,r6,r10
	177	beq 13f
	178
	179	srdi r6,r5,4
	180	mtctr r6
	181	mr r8,r3
	182	12:
	183	err1; std r0,0(r3)
	184	err1; std r0,8(r3)
	185	addi r3,r3,16
	186	bdnz 12b
	187
	188	sub r4,r4,r5
	189
	190	13: srd r6,r4,r7
	191	mtctr r6
	192	mr r8,r3
	193	14:
	194	err1; dcbz r0,r3
	195	add r3,r3,r9
	196	bdnz 14b
	197
	198	and r4,r4,r10
	199
	200	cmpdi r4,32
	201	blt .Lshort_clear
	202	b .Lmedium_clear