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-rw-r--r--arch/mips/lib/strnlen_user.S64
1 files changed, 64 insertions, 0 deletions
diff --git a/arch/mips/lib/strnlen_user.S b/arch/mips/lib/strnlen_user.S
new file mode 100644
index 0000000000..c192a6f6cd
--- /dev/null
+++ b/arch/mips/lib/strnlen_user.S
@@ -0,0 +1,64 @@
+/*
+ * 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, 1998, 1999, 2004 by Ralf Baechle
+ * Copyright (c) 1999 Silicon Graphics, Inc.
+ */
+#include <linux/export.h>
+#include <asm/asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/regdef.h>
+
+#define EX(insn,reg,addr,handler) \
+9: insn reg, addr; \
+ .section __ex_table,"a"; \
+ PTR_WD 9b, handler; \
+ .previous
+
+/*
+ * Return the size of a string including the ending NUL character up to a
+ * maximum of a1 or 0 in case of error.
+ *
+ * Note: for performance reasons we deliberately accept that a user may
+ * make strlen_user and strnlen_user access the first few KSEG0
+ * bytes. There's nothing secret there. On 64-bit accessing beyond
+ * the maximum is a tad hairier ...
+ */
+LEAF(__strnlen_user_asm)
+ move v0, a0
+ PTR_ADDU a1, a0 # stop pointer
+1:
+#ifdef CONFIG_CPU_DADDI_WORKAROUNDS
+ .set noat
+ li AT, 1
+#endif
+ beq v0, a1, 1f # limit reached?
+#ifdef CONFIG_EVA
+ .set push
+ .set eva
+ EX(lbe, t0, (v0), .Lfault)
+ .set pop
+#else
+ EX(lb, t0, (v0), .Lfault)
+#endif
+ .set noreorder
+ bnez t0, 1b
+1:
+#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
+ PTR_ADDIU v0, 1
+#else
+ PTR_ADDU v0, AT
+ .set at
+#endif
+ .set reorder
+ PTR_SUBU v0, a0
+ jr ra
+ END(__strnlen_user_asm)
+
+.Lfault:
+ move v0, zero
+ jr ra
+
+ EXPORT_SYMBOL(__strnlen_user_asm)