diff options
Diffstat (limited to 'kernel/arch/avr32/lib/strncpy_from_user.S')
| -rw-r--r-- | kernel/arch/avr32/lib/strncpy_from_user.S | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/kernel/arch/avr32/lib/strncpy_from_user.S b/kernel/arch/avr32/lib/strncpy_from_user.S new file mode 100644 index 000000000..72bd50599 --- /dev/null +++ b/kernel/arch/avr32/lib/strncpy_from_user.S @@ -0,0 +1,60 @@ +/* + * 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 |