unicore32 additional architecture files: low-level lib: uaccess

[pandora-kernel.git] / arch / unicore32 / lib / strncpy_from_user.S

diff --git a/arch/unicore32/lib/strncpy_from_user.S b/arch/unicore32/lib/strncpy_from_user.S
new file mode 100644 (file)
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--- /dev/null
+++ b/arch/unicore32/lib/strncpy_from_user.S
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+/*
+ * linux/arch/unicore32/lib/strncpy_from_user.S
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * 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/linkage.h>
+#include <asm/assembler.h>
+#include <asm/errno.h>
+
+       .text
+       .align  5
+
+/*
+ * Copy a string from user space to kernel space.
+ *  r0 = dst, r1 = src, r2 = byte length
+ * returns the number of characters copied (strlen of copied string),
+ *  -EFAULT on exception, or "len" if we fill the whole buffer
+ */
+ENTRY(__strncpy_from_user)
+       mov     ip, r1
+1:     sub.a   r2, r2, #1
+       ldrusr  r3, r1, 1, ns
+       bfs     2f
+       stb.w   r3, [r0]+, #1
+       cxor.a  r3, #0
+       bne     1b
+       sub     r1, r1, #1      @ take NUL character out of count
+2:     sub     r0, r1, ip
+       mov     pc, lr
+ENDPROC(__strncpy_from_user)
+
+       .pushsection .fixup,"ax"
+       .align  0
+9001:  mov     r3, #0
+       stb     r3, [r0+], #0   @ null terminate
+       mov     r0, #-EFAULT
+       mov     pc, lr
+       .popsection
+