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Diffstat (limited to 'arch/mips/lib/strncpy_user.S')
| -rw-r--r-- | arch/mips/lib/strncpy_user.S | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/arch/mips/lib/strncpy_user.S b/arch/mips/lib/strncpy_user.S new file mode 100644 index 00000000..92870b6b --- /dev/null +++ b/arch/mips/lib/strncpy_user.S @@ -0,0 +1,61 @@ +/* + * 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 <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 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) + LONG_L v0, TI_ADDR_LIMIT($28) # pointer ok? + and v0, a1 + bnez v0, .Lfault + +FEXPORT(__strncpy_from_user_nocheck_asm) + .set noreorder + move t0, zero + move v1, a1 +1: EX(lbu, v0, (v1), .Lfault) + PTR_ADDIU v1, 1 + R10KCBARRIER(0(ra)) + beqz v0, 2f + sb v0, (a0) + PTR_ADDIU t0, 1 + bne t0, a2, 1b + PTR_ADDIU a0, 1 +2: PTR_ADDU v0, a1, t0 + xor v0, a1 + bltz v0, .Lfault + nop + jr ra # return n + move v0, t0 + END(__strncpy_from_user_asm) + +.Lfault: jr ra + li v0, -EFAULT + + .section __ex_table,"a" + PTR 1b, .Lfault + .previous |