[linux-2.6-block.git] / arch / arm64 / lib / clear_user.S

/*
 * Based on arch/arm/lib/clear_user.S
 *
 * Copyright (C) 2012 ARM Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */
#include <linux/linkage.h>
#include <asm/assembler.h>

	.text

/* Prototype: int __clear_user(void *addr, size_t sz)
 * Purpose  : clear some user memory
 * Params   : addr - user memory address to clear
 *          : sz   - number of bytes to clear
 * Returns  : number of bytes NOT cleared
 *
 * Alignment fixed up by hardware.
 */
ENTRY(__clear_user)
	mov	x2, x1			// save the size for fixup return
	subs	x1, x1, #8
	b.mi	2f
1:
USER(9f, str	xzr, [x0], #8	)
	subs	x1, x1, #8
	b.pl	1b
2:	adds	x1, x1, #4
	b.mi	3f
USER(9f, str	wzr, [x0], #4	)
	sub	x1, x1, #4
3:	adds	x1, x1, #2
	b.mi	4f
USER(9f, strh	wzr, [x0], #2	)
	sub	x1, x1, #2
4:	adds	x1, x1, #1
	b.mi	5f
	strb	wzr, [x0]
5:	mov	x0, #0
	ret
ENDPROC(__clear_user)

	.section .fixup,"ax"
	.align	2
9:	mov	x0, x2			// return the original size
	ret
	.previous
Commit	Line	Data
0aea86a2 CM	1	/*
	2	* Based on arch/arm/lib/clear_user.S
	3	*
	4	* Copyright (C) 2012 ARM Ltd.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	17	*/
	18	#include <linux/linkage.h>
	19	#include <asm/assembler.h>
	20
	21	.text
	22
	23	/* Prototype: int __clear_user(void *addr, size_t sz)
	24	* Purpose : clear some user memory
	25	* Params : addr - user memory address to clear
	26	* : sz - number of bytes to clear
	27	* Returns : number of bytes NOT cleared
	28	*
	29	* Alignment fixed up by hardware.
	30	*/
	31	ENTRY(__clear_user)
	32	mov x2, x1 // save the size for fixup return
	33	subs x1, x1, #8
	34	b.mi 2f
	35	1:
	36	USER(9f, str xzr, [x0], #8 )
	37	subs x1, x1, #8
	38	b.pl 1b
	39	2: adds x1, x1, #4
	40	b.mi 3f
	41	USER(9f, str wzr, [x0], #4 )
	42	sub x1, x1, #4
	43	3: adds x1, x1, #2
	44	b.mi 4f
	45	USER(9f, strh wzr, [x0], #2 )
	46	sub x1, x1, #2
	47	4: adds x1, x1, #1
	48	b.mi 5f
	49	strb wzr, [x0]
	50	5: mov x0, #0
	51	ret
	52	ENDPROC(__clear_user)
	53
	54	.section .fixup,"ax"
	55	.align 2
	56	9: mov x0, x2 // return the original size
	57	ret
	58	.previous