/*
 * 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
 * Copyright (C) 2011 MIPS Technologies, Inc.
 */
#include <linux/errno.h>
#include <linux/export.h>
#include <asm/asm.h>
#include <asm/asm-offsets.h>
#include <asm/regdef.h>

#define EX(insn,reg,addr,handler)                       \
9:      insn    reg, addr;                              \
        .section __ex_table,"a";                        \
        PTR_WD  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)
        move            t0, zero
        move            v1, a1
#ifdef CONFIG_EVA
        .set push
        .set eva
1:      EX(lbue, v0, (v1), .Lfault)
        .set pop
#else
1:      EX(lbu, v0, (v1), .Lfault)
#endif
        PTR_ADDIU       v1, 1
        R10KCBARRIER(0(ra))
        sb              v0, (a0)
        beqz            v0, 2f
        PTR_ADDIU       t0, 1
        PTR_ADDIU       a0, 1
        bne             t0, a2, 1b
2:      PTR_ADDU        v0, a1, t0
        xor             v0, a1
        bltz            v0, .Lfault
        move            v0, t0
        jr              ra                      # return n
        END(__strncpy_from_user_asm)

.Lfault:
        li              v0, -EFAULT
        jr              ra

        .section        __ex_table,"a"
        PTR_WD          1b, .Lfault
        .previous

        EXPORT_SYMBOL(__strncpy_from_user_asm)