| Haavard Skinnemoen | 5f97f7f | 2006-09-25 23:32:13 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copy to/from userspace with optional address space checking. |
| 3 | * |
| 4 | * Copyright 2004-2006 Atmel Corporation |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | */ |
| 10 | #include <linux/errno.h> |
| 11 | |
| 12 | #include <asm/page.h> |
| 13 | #include <asm/thread_info.h> |
| 14 | #include <asm/asm.h> |
| 15 | |
| 16 | /* |
| 17 | * long strncpy_from_user(char *dst, const char *src, long count) |
| 18 | * |
| 19 | * On success, returns the length of the string, not including |
| 20 | * the terminating NUL. |
| 21 | * |
| 22 | * If the string is longer than count, returns count |
| 23 | * |
| 24 | * If userspace access fails, returns -EFAULT |
| 25 | */ |
| 26 | .text |
| 27 | .align 1 |
| 28 | .global strncpy_from_user |
| 29 | .type strncpy_from_user, "function" |
| 30 | strncpy_from_user: |
| 31 | mov r9, -EFAULT |
| 32 | branch_if_kernel r8, __strncpy_from_user |
| 33 | ret_if_privileged r8, r11, r10, r9 |
| 34 | |
| 35 | .global __strncpy_from_user |
| 36 | .type __strncpy_from_user, "function" |
| 37 | __strncpy_from_user: |
| 38 | cp.w r10, 0 |
| 39 | reteq 0 |
| 40 | |
| 41 | mov r9, r10 |
| 42 | |
| 43 | 1: ld.ub r8, r11++ |
| 44 | st.b r12++, r8 |
| 45 | cp.w r8, 0 |
| 46 | breq 2f |
| 47 | sub r9, 1 |
| 48 | brne 1b |
| 49 | |
| 50 | 2: sub r10, r9 |
| 51 | retal r10 |
| 52 | |
| 53 | .section .fixup, "ax" |
| 54 | .align 1 |
| 55 | 3: mov r12, -EFAULT |
| 56 | retal r12 |
| 57 | |
| 58 | .section __ex_table, "a" |
| 59 | .align 2 |
| 60 | .long 1b, 3b |