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-rw-r--r--arch/loongarch/lib/copy_user.S47
1 files changed, 47 insertions, 0 deletions
diff --git a/arch/loongarch/lib/copy_user.S b/arch/loongarch/lib/copy_user.S
new file mode 100644
index 000000000..97d20327a
--- /dev/null
+++ b/arch/loongarch/lib/copy_user.S
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+
+#include <asm/asm.h>
+#include <asm/asmmacro.h>
+#include <asm/export.h>
+#include <asm/regdef.h>
+
+.macro fixup_ex from, to, offset, fix
+.if \fix
+ .section .fixup, "ax"
+\to: addi.d a0, a2, \offset
+ jr ra
+ .previous
+.endif
+ .section __ex_table, "a"
+ PTR \from\()b, \to\()b
+ .previous
+.endm
+
+/*
+ * unsigned long __copy_user(void *to, const void *from, size_t n)
+ *
+ * a0: to
+ * a1: from
+ * a2: n
+ */
+SYM_FUNC_START(__copy_user)
+ beqz a2, 3f
+
+1: ld.b t0, a1, 0
+2: st.b t0, a0, 0
+ addi.d a0, a0, 1
+ addi.d a1, a1, 1
+ addi.d a2, a2, -1
+ bgtz a2, 1b
+
+3: move a0, a2
+ jr ra
+
+ fixup_ex 1, 4, 0, 1
+ fixup_ex 2, 4, 0, 0
+SYM_FUNC_END(__copy_user)
+
+EXPORT_SYMBOL(__copy_user)