| Catalin Marinas | 0aea86a | 2012-03-05 11:49:32 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Based on arch/arm/lib/strncpy_from_user.S |
| 3 | * |
| 4 | * Copyright (C) 1995-2000 Russell King |
| 5 | * Copyright (C) 2012 ARM Ltd. |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License version 2 as |
| 9 | * published by the Free Software Foundation. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 18 | */ |
| 19 | |
| 20 | #include <linux/linkage.h> |
| 21 | #include <asm/assembler.h> |
| 22 | #include <asm/errno.h> |
| 23 | |
| 24 | .text |
| 25 | .align 5 |
| 26 | |
| 27 | /* |
| 28 | * Copy a string from user space to kernel space. |
| 29 | * x0 = dst, x1 = src, x2 = byte length |
| 30 | * returns the number of characters copied (strlen of copied string), |
| 31 | * -EFAULT on exception, or "len" if we fill the whole buffer |
| 32 | */ |
| 33 | ENTRY(__strncpy_from_user) |
| 34 | mov x4, x1 |
| 35 | 1: subs x2, x2, #1 |
| 36 | bmi 2f |
| 37 | USER(9f, ldrb w3, [x1], #1 ) |
| 38 | strb w3, [x0], #1 |
| 39 | cbnz w3, 1b |
| 40 | sub x1, x1, #1 // take NUL character out of count |
| 41 | 2: sub x0, x1, x4 |
| 42 | ret |
| 43 | ENDPROC(__strncpy_from_user) |
| 44 | |
| 45 | .section .fixup,"ax" |
| 46 | .align 0 |
| 47 | 9: strb wzr, [x0] // null terminate |
| 48 | mov x0, #-EFAULT |
| 49 | ret |
| 50 | .previous |