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Diffstat (limited to 'arch/mips/lib/strnlen_user.S')
| -rw-r--r-- | arch/mips/lib/strnlen_user.S | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/arch/mips/lib/strnlen_user.S b/arch/mips/lib/strnlen_user.S new file mode 100644 index 00000000000..6e7a8eed4de --- /dev/null +++ b/arch/mips/lib/strnlen_user.S @@ -0,0 +1,45 @@ +/* + * 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, 1998, 1999, 2004 by Ralf Baechle + * Copyright (c) 1999 Silicon Graphics, Inc. + */ +#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 + +/* + * Return the size of a string including the ending NUL character upto a + * maximum of a1 or 0 in case of error. + * + * Note: for performance reasons we deliberately accept that a user may + * make strlen_user and strnlen_user access the first few KSEG0 + * bytes. There's nothing secret there. On 64-bit accessing beyond + * the maximum is a tad hairier ... + */ +LEAF(__strnlen_user_asm) + LONG_L v0, TI_ADDR_LIMIT($28) # pointer ok? + and v0, a0 + bnez v0, fault + +FEXPORT(__strnlen_user_nocheck_asm) + move v0, a0 + PTR_ADDU a1, a0 # stop pointer +1: beq v0, a1, 1f # limit reached? + EX(lb, t0, (v0), fault) + PTR_ADDU v0, 1 + bnez t0, 1b +1: PTR_SUBU v0, a0 + jr ra + END(__strnlen_user_asm) + +fault: move v0, zero + jr ra |