diff options
Diffstat (limited to 'arch/mips/lib/strnlen_user.S')
| -rw-r--r-- | arch/mips/lib/strnlen_user.S | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/arch/mips/lib/strnlen_user.S b/arch/mips/lib/strnlen_user.S new file mode 100644 index 0000000000..c192a6f6cd --- /dev/null +++ b/arch/mips/lib/strnlen_user.S @@ -0,0 +1,64 @@ +/* + * 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 <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 + +/* + * Return the size of a string including the ending NUL character up to 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) + move v0, a0 + PTR_ADDU a1, a0 # stop pointer +1: +#ifdef CONFIG_CPU_DADDI_WORKAROUNDS + .set noat + li AT, 1 +#endif + beq v0, a1, 1f # limit reached? +#ifdef CONFIG_EVA + .set push + .set eva + EX(lbe, t0, (v0), .Lfault) + .set pop +#else + EX(lb, t0, (v0), .Lfault) +#endif + .set noreorder + bnez t0, 1b +1: +#ifndef CONFIG_CPU_DADDI_WORKAROUNDS + PTR_ADDIU v0, 1 +#else + PTR_ADDU v0, AT + .set at +#endif + .set reorder + PTR_SUBU v0, a0 + jr ra + END(__strnlen_user_asm) + +.Lfault: + move v0, zero + jr ra + + EXPORT_SYMBOL(__strnlen_user_asm) |