arch/arm/lib/putuser.S

root/arch/arm/lib/putuser.S
/* SPDX-License-Identifier: GPL-2.0-only */
/*
 *  linux/arch/arm/lib/putuser.S
 *
 *  Copyright (C) 2001 Russell King
 *
 *  Idea from x86 version, (C) Copyright 1998 Linus Torvalds
 *
 * These functions have a non-standard call interface to make
 * them more efficient, especially as they return an error
 * value in addition to the "real" return value.
 *
 * __put_user_X
 *
 * Inputs:      r0 contains the address
 *              r1 contains the address limit, which must be preserved
 *              r2, r3 contains the value
 * Outputs:     r0 is the error code
 *              lr corrupted
 *
 * No other registers must be altered.  (see <asm/uaccess.h>
 * for specific ASM register usage).
 *
 * Note that ADDR_LIMIT is either 0 or 0xc0000000
 * Note also that it is intended that __put_user_bad is not global.
 */
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/errno.h>
#include <asm/domain.h>

ENTRY(__put_user_1)
        check_uaccess r0, 1, r1, ip, __put_user_bad
1: TUSER(strb)  r2, [r0]
        mov     r0, #0
        ret     lr
ENDPROC(__put_user_1)

ENTRY(__put_user_2)
        check_uaccess r0, 2, r1, ip, __put_user_bad
#if __LINUX_ARM_ARCH__ >= 6

2: TUSER(strh)  r2, [r0]

#else

        mov     ip, r2, lsr #8
#ifndef __ARMEB__
2: TUSER(strb)  r2, [r0], #1
3: TUSER(strb)  ip, [r0]
#else
2: TUSER(strb)  ip, [r0], #1
3: TUSER(strb)  r2, [r0]
#endif

#endif /* __LINUX_ARM_ARCH__ >= 6 */
        mov     r0, #0
        ret     lr
ENDPROC(__put_user_2)

ENTRY(__put_user_4)
        check_uaccess r0, 4, r1, ip, __put_user_bad
4: TUSER(str)   r2, [r0]
        mov     r0, #0
        ret     lr
ENDPROC(__put_user_4)

ENTRY(__put_user_8)
        check_uaccess r0, 8, r1, ip, __put_user_bad
#ifdef CONFIG_THUMB2_KERNEL
5: TUSER(str)   r2, [r0]
6: TUSER(str)   r3, [r0, #4]
#else
5: TUSER(str)   r2, [r0], #4
6: TUSER(str)   r3, [r0]
#endif
        mov     r0, #0
        ret     lr
ENDPROC(__put_user_8)

__put_user_bad:
        mov     r0, #-EFAULT
        ret     lr
ENDPROC(__put_user_bad)

.pushsection __ex_table, "a"
        .long   1b, __put_user_bad
        .long   2b, __put_user_bad
#if __LINUX_ARM_ARCH__ < 6
        .long   3b, __put_user_bad
#endif
        .long   4b, __put_user_bad
        .long   5b, __put_user_bad
        .long   6b, __put_user_bad
.popsection
Linux
