diff options
Diffstat (limited to 'arch/mips/lib/strncpy_user.S')
| -rw-r--r-- | arch/mips/lib/strncpy_user.S | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/arch/mips/lib/strncpy_user.S b/arch/mips/lib/strncpy_user.S new file mode 100644 index 000000000000..14bed17c1648 --- /dev/null +++ b/arch/mips/lib/strncpy_user.S @@ -0,0 +1,58 @@ +/* + * 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 + */ +#include <linux/errno.h> +#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 + +/* + * 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, fault + +FEXPORT(__strncpy_from_user_nocheck_asm) + move v0, zero + move v1, a1 + .set noreorder +1: EX(lbu, t0, (v1), fault) + PTR_ADDIU v1, 1 + beqz t0, 2f + sb t0, (a0) + PTR_ADDIU v0, 1 + bne v0, a2, 1b + PTR_ADDIU a0, 1 + .set reorder +2: PTR_ADDU t0, a1, v0 + xor t0, a1 + bltz t0, fault + jr ra # return n + END(__strncpy_from_user_asm) + +fault: li v0, -EFAULT + jr ra + + .section __ex_table,"a" + PTR 1b, fault + .previous |