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diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
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+/*
+ * Tracing hooks
+ *
+ * Copyright (C) 2008 Red Hat, Inc.  All rights reserved.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU General Public License v.2.
+ *
+ * This file defines hook entry points called by core code where
+ * user tracing/debugging support might need to do something.  These
+ * entry points are called tracehook_*().  Each hook declared below
+ * has a detailed kerneldoc comment giving the context (locking et
+ * al) from which it is called, and the meaning of its return value.
+ *
+ * Each function here typically has only one call site, so it is ok
+ * to have some nontrivial tracehook_*() inlines.  In all cases, the
+ * fast path when no tracing is enabled should be very short.
+ *
+ * The purpose of this file and the tracehook_* layer is to consolidate
+ * the interface that the kernel core and arch code uses to enable any
+ * user debugging or tracing facility (such as ptrace).  The interfaces
+ * here are carefully documented so that maintainers of core and arch
+ * code do not need to think about the implementation details of the
+ * tracing facilities.  Likewise, maintainers of the tracing code do not
+ * need to understand all the calling core or arch code in detail, just
+ * documented circumstances of each call, such as locking conditions.
+ *
+ * If the calling core code changes so that locking is different, then
+ * it is ok to change the interface documented here.  The maintainer of
+ * core code changing should notify the maintainers of the tracing code
+ * that they need to work out the change.
+ *
+ * Some tracehook_*() inlines take arguments that the current tracing
+ * implementations might not necessarily use.  These function signatures
+ * are chosen to pass in all the information that is on hand in the
+ * caller and might conceivably be relevant to a tracer, so that the
+ * core code won't have to be updated when tracing adds more features.
+ * If a call site changes so that some of those parameters are no longer
+ * already on hand without extra work, then the tracehook_* interface
+ * can change so there is no make-work burden on the core code.  The
+ * maintainer of core code changing should notify the maintainers of the
+ * tracing code that they need to work out the change.
+ */
+
+#ifndef _LINUX_TRACEHOOK_H
+#define _LINUX_TRACEHOOK_H	1
+
+#include <linux/sched.h>
+#include <linux/ptrace.h>
+
+#endif	/* <linux/tracehook.h> */