| /* |
| * Copy to/from userspace with optional address space checking. |
| * |
| * Copyright 2004-2006 Atmel Corporation |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| #include <linux/errno.h> |
| |
| #include <asm/page.h> |
| #include <asm/thread_info.h> |
| #include <asm/asm.h> |
| |
| /* |
| * long strncpy_from_user(char *dst, const char *src, long count) |
| * |
| * On success, returns the length of the string, not including |
| * the terminating NUL. |
| * |
| * If the string is longer than count, returns count |
| * |
| * If userspace access fails, returns -EFAULT |
| */ |
| .text |
| .align 1 |
| .global strncpy_from_user |
| .type strncpy_from_user, "function" |
| strncpy_from_user: |
| mov r9, -EFAULT |
| branch_if_kernel r8, __strncpy_from_user |
| ret_if_privileged r8, r11, r10, r9 |
| |
| .global __strncpy_from_user |
| .type __strncpy_from_user, "function" |
| __strncpy_from_user: |
| cp.w r10, 0 |
| reteq 0 |
| |
| mov r9, r10 |
| |
| 1: ld.ub r8, r11++ |
| st.b r12++, r8 |
| cp.w r8, 0 |
| breq 2f |
| sub r9, 1 |
| brne 1b |
| |
| 2: sub r10, r9 |
| retal r10 |
| |
| .section .fixup, "ax" |
| .align 1 |
| 3: mov r12, -EFAULT |
| retal r12 |
| |
| .section __ex_table, "a" |
| .align 2 |
| .long 1b, 3b |
