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/*
 *  linux/arch/arm/lib/getuser.S
 *
 *  Copyright (C) 2001 Russell King
 *
 * 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.
 *
 *  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.
 *
 * __get_user_X
 *
 * Inputs:      r0 contains the address
 * Outputs:     r0 is the error code
 *              r1, r2 contains the zero-extended value
 *              lr corrupted
 *
 * No other registers must be altered.  (see include/asm-arm/uaccess.h
 * for specific ASM register usage).
 *
 * Note that ADDR_LIMIT is either 0 or 0xc0000000.
 * Note also that it is intended that __get_user_bad is not global.
 */
#include <asm/constants.h>

        .global __get_user_1
__get_user_1:
        bic     r1, sp, #0x1f00
        bic     r1, r1, #0x00ff
        ldr     r1, [r1, #TSK_ADDR_LIMIT]
        sub     r1, r1, #1
        cmp     r0, r1
1:      ldrlsbt r1, [r0]
        movls   r0, #0
        movls   pc, lr
        b       __get_user_bad

        .global __get_user_2
__get_user_2:
        bic     r2, sp, #0x1f00
        bic     r2, r2, #0x00ff
        ldr     r2, [r2, #TSK_ADDR_LIMIT]
        sub     r2, r2, #2
        cmp     r0, r2
2:      ldrlsbt r1, [r0], #1
3:      ldrlsbt r2, [r0]
        orrls   r1, r1, r2, lsl #8
        movls   r0, #0
        movls   pc, lr
        b       __get_user_bad

        .global __get_user_4
__get_user_4:
        bic     r1, sp, #0x1f00
        bic     r1, r1, #0x00ff
        ldr     r1, [r1, #TSK_ADDR_LIMIT]
        sub     r1, r1, #4
        cmp     r0, r1
4:      ldrlst  r1, [r0]
        movls   r0, #0
        movls   pc, lr
        b       __get_user_bad

        .global __get_user_8
__get_user_8:
        bic     r2, sp, #0x1f00
        bic     r2, r2, #0x00ff
        ldr     r2, [r2, #TSK_ADDR_LIMIT]
        sub     r2, r2, #8
        cmp     r0, r2
5:      ldrlst  r1, [r0], #4
6:      ldrlst  r2, [r0]
        movls   r0, #0
        movls   pc, lr

        /* fall through */

__get_user_bad_8:
        mov     r2, #0
__get_user_bad:
        mov     r1, #0
        mov     r0, #-14
        mov     pc, lr

.section __ex_table, "a"
        .long   1b, __get_user_bad
        .long   2b, __get_user_bad
        .long   3b, __get_user_bad
        .long   4b, __get_user_bad
        .long   5b, __get_user_bad_8
        .long   6b, __get_user_bad_8
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