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Diffstat (limited to 'arch/mips/lib/strnlen_user.S')
| -rw-r--r-- | arch/mips/lib/strnlen_user.S | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/arch/mips/lib/strnlen_user.S b/arch/mips/lib/strnlen_user.S new file mode 100644 index 000000000..0ae411834 --- /dev/null +++ b/arch/mips/lib/strnlen_user.S @@ -0,0 +1,54 @@ +/* $Id: strnlen_user.S,v 1.2 1999/11/19 20:35:21 ralf Exp $ + * + * 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 by Ralf Baechle + * Copyright (c) 1999 Silicon Graphics, Inc. + */ +#include <asm/asm.h> +#include <asm/offset.h> +#include <asm/regdef.h> +#include <asm/sgidefs.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 0) + * + * Return 0 for error, len of string but at max a1 otherwise + * + * 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 ... + */ +LEAF(__strnlen_user_asm) + lw v0, THREAD_CURDS($28) # pointer ok? + and v0, a0 + bltz v0, fault + +EXPORT(__strnlen_user_nocheck_asm) + .type __strnlen_user_nocheck_asm,@function + move v0, a0 + addu a1, a0 # stop pointer + .set noreorder +1: beq v0, a1, 1f # limit reached? + addiu v0, 1 + .set reorder + EX(lb, t0, -1(v0), fault) + bnez t0, 1b +1: subu v0, a0 + jr ra + END(__strnlen_user_asm) + + .section __ex_table,"a" + PTR 1b, fault + .previous + +fault: move v0, zero + jr ra |