1 files changed, 58 insertions, 0 deletions

diff --git a/arch/mips/lib/strncpy_user.S b/arch/mips/lib/strncpy_user.S
new file mode 100644
index 000000000000..14bed17c1648
--- /dev/null
+++ b/arch/mips/lib/strncpy_user.S
@@ -0,0 +1,58 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 1996, 1999 by Ralf Baechle
+ */
+#include <linux/errno.h>
+#include <asm/asm.h>
+#include <asm/offset.h>
+#include <asm/regdef.h>
+
+#define EX(insn,reg,addr,handler)                       \
+9:      insn    reg, addr;                              \
+        .section __ex_table,"a";                        \
+        PTR     9b, handler;                            \
+        .previous
+
+/*
+ * Returns: -EFAULT if exception before terminator, N if the entire
+ * buffer filled, else strlen.
+ */
+
+/*
+ * Ugly special case have to check: we might get passed a user space
+ * pointer which wraps into the kernel space.  We don't deal with that.  If
+ * it happens at most some bytes of the exceptions handlers will be copied.
+ */
+
+LEAF(__strncpy_from_user_asm)
+        LONG_L          v0, TI_ADDR_LIMIT($28)  # pointer ok?
+        and             v0, a1
+        bnez            v0, fault
+
+FEXPORT(__strncpy_from_user_nocheck_asm)
+        move            v0, zero
+        move            v1, a1
+        .set            noreorder
+1:      EX(lbu, t0, (v1), fault)
+        PTR_ADDIU       v1, 1
+        beqz            t0, 2f
+         sb             t0, (a0)
+        PTR_ADDIU       v0, 1
+        bne             v0, a2, 1b
+         PTR_ADDIU      a0, 1
+        .set            reorder
+2:      PTR_ADDU        t0, a1, v0
+        xor             t0, a1
+        bltz            t0, fault
+        jr              ra                      # return n
+        END(__strncpy_from_user_asm)
+
+fault:  li              v0, -EFAULT
+        jr              ra
+
+        .section        __ex_table,"a"
+        PTR             1b, fault
+        .previous