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-rw-r--r--arch/csky/include/asm/vdso.h27
1 files changed, 27 insertions, 0 deletions
diff --git a/arch/csky/include/asm/vdso.h b/arch/csky/include/asm/vdso.h
new file mode 100644
index 0000000000..bdce581b5f
--- /dev/null
+++ b/arch/csky/include/asm/vdso.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_CSKY_VDSO_H
+#define __ASM_CSKY_VDSO_H
+
+#include <linux/types.h>
+
+#ifndef GENERIC_TIME_VSYSCALL
+struct vdso_data {
+};
+#endif
+
+/*
+ * The VDSO symbols are mapped into Linux so we can just use regular symbol
+ * addressing to get their offsets in userspace. The symbols are mapped at an
+ * offset of 0, but since the linker must support setting weak undefined
+ * symbols to the absolute address 0 it also happens to support other low
+ * addresses even when the code model suggests those low addresses would not
+ * otherwise be available.
+ */
+#define VDSO_SYMBOL(base, name) \
+({ \
+ extern const char __vdso_##name[]; \
+ (void __user *)((unsigned long)(base) + __vdso_##name); \
+})
+
+#endif /* __ASM_CSKY_VDSO_H */