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/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (c) 1996, 1999 by Ralf Baechle
 */
#include <linux/errno.h>
#include <asm/asm.h>
#include <asm/offset.h>
#include <asm/regdef.h>

#define EX(insn,reg,addr,handler)                       \
9:      insn    reg, addr;                              \
        .section __ex_table,"a";                        \
        PTR     9b, handler;                            \
        .previous

/*
 * Returns: -EFAULT if exception before terminator, N if the entire
 * buffer filled, else strlen.
 */

/*
 * Ugly special case have to check: we might get passed a user space
 * pointer which wraps into the kernel space.  We don't deal with that.  If
 * it happens at most some bytes of the exceptions handlers will be copied.
 */

LEAF(__strncpy_from_user_asm)
        lw      v0, THREAD_CURDS($28)   # pointer ok?
        and     v0, a1
        bltz    v0, fault

EXPORT(__strncpy_from_user_nocheck_asm)
        move    v0, zero
        move    v1, a1
        .set    noreorder
1:      EX(lbu,  t0, (v1), fault)
        addiu   v1, v1, 1
        beqz    t0, 2f
         sb     t0, (a0)
        addiu   v0, 1
        bne     v0, a2, 1b
         addiu  a0, 1
        .set    reorder
2:      addu    t0, a1, v0
        xor     t0, a1
        bltz    t0, fault
        jr      ra                              # return n
        END(__strncpy_from_user_asm)

fault:  li      v0, -EFAULT
        jr      ra

        .section __ex_table,"a"
        PTR     1b, fault
        .previous