| 1 | /* |
| 2 | * linux/arch/unicore32/lib/strncpy_from_user.S |
| 3 | * |
| 4 | * Code specific to PKUnity SoC and UniCore ISA |
| 5 | * |
| 6 | * Copyright (C) 2001-2010 GUAN Xue-tao |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License version 2 as |
| 10 | * published by the Free Software Foundation. |
| 11 | */ |
| 12 | #include <linux/linkage.h> |
| 13 | #include <asm/assembler.h> |
| 14 | #include <asm/errno.h> |
| 15 | |
| 16 | .text |
| 17 | .align 5 |
| 18 | |
| 19 | /* |
| 20 | * Copy a string from user space to kernel space. |
| 21 | * r0 = dst, r1 = src, r2 = byte length |
| 22 | * returns the number of characters copied (strlen of copied string), |
| 23 | * -EFAULT on exception, or "len" if we fill the whole buffer |
| 24 | */ |
| 25 | ENTRY(__strncpy_from_user) |
| 26 | mov ip, r1 |
| 27 | 1: sub.a r2, r2, #1 |
| 28 | ldrusr r3, r1, 1, ns |
| 29 | bfs 2f |
| 30 | stb.w r3, [r0]+, #1 |
| 31 | cxor.a r3, #0 |
| 32 | bne 1b |
| 33 | sub r1, r1, #1 @ take NUL character out of count |
| 34 | 2: sub r0, r1, ip |
| 35 | mov pc, lr |
| 36 | ENDPROC(__strncpy_from_user) |
| 37 | |
| 38 | .pushsection .fixup,"ax" |
| 39 | .align 0 |
| 40 | 9001: mov r3, #0 |
| 41 | stb r3, [r0+], #0 @ null terminate |
| 42 | mov r0, #-EFAULT |
| 43 | mov pc, lr |
| 44 | .popsection |
| 45 | |