1 files changed, 150 insertions, 0 deletions
diff --git a/include/linux/fprobe.h b/include/linux/fprobe.h
new file mode 100644
index 000000000000..702099f08929
--- /dev/null
+++ b/include/linux/fprobe.h
@@ -0,0 +1,150 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Simple ftrace probe wrapper */
+#ifndef _LINUX_FPROBE_H
+#define _LINUX_FPROBE_H
+
+#include <linux/compiler.h>
+#include <linux/ftrace.h>
+#include <linux/rcupdate.h>
+#include <linux/refcount.h>
+#include <linux/slab.h>
+
+struct fprobe;
+typedef int (*fprobe_entry_cb)(struct fprobe *fp, unsigned long entry_ip,
+			       unsigned long ret_ip, struct ftrace_regs *regs,
+			       void *entry_data);
+
+typedef void (*fprobe_exit_cb)(struct fprobe *fp, unsigned long entry_ip,
+			       unsigned long ret_ip, struct ftrace_regs *regs,
+			       void *entry_data);
+
+/**
+ * struct fprobe_hlist_node - address based hash list node for fprobe.
+ *
+ * @hlist: The hlist node for address search hash table.
+ * @addr: One of the probing address of @fp.
+ * @fp: The fprobe which owns this.
+ */
+struct fprobe_hlist_node {
+	struct hlist_node	hlist;
+	unsigned long		addr;
+	struct fprobe		*fp;
+};
+
+/**
+ * struct fprobe_hlist - hash list nodes for fprobe.
+ *
+ * @hlist: The hlist node for existence checking hash table.
+ * @rcu: rcu_head for RCU deferred release.
+ * @fp: The fprobe which owns this fprobe_hlist.
+ * @size: The size of @array.
+ * @array: The fprobe_hlist_node for each address to probe.
+ */
+struct fprobe_hlist {
+	struct hlist_node		hlist;
+	struct rcu_head			rcu;
+	struct fprobe			*fp;
+	int				size;
+	struct fprobe_hlist_node	array[] __counted_by(size);
+};
+
+/**
+ * struct fprobe - ftrace based probe.
+ *
+ * @nmissed: The counter for missing events.
+ * @flags: The status flag.
+ * @entry_data_size: The private data storage size.
+ * @entry_handler: The callback function for function entry.
+ * @exit_handler: The callback function for function exit.
+ * @hlist_array: The fprobe_hlist for fprobe search from IP hash table.
+ */
+struct fprobe {
+	unsigned long		nmissed;
+	unsigned int		flags;
+	size_t			entry_data_size;
+
+	fprobe_entry_cb entry_handler;
+	fprobe_exit_cb  exit_handler;
+
+	struct fprobe_hlist	*hlist_array;
+};
+
+/* This fprobe is soft-disabled. */
+#define FPROBE_FL_DISABLED	1
+
+/*
+ * This fprobe handler will be shared with kprobes.
+ * This flag must be set before registering.
+ */
+#define FPROBE_FL_KPROBE_SHARED	2
+
+static inline bool fprobe_disabled(struct fprobe *fp)
+{
+	return (fp) ? fp->flags & FPROBE_FL_DISABLED : false;
+}
+
+static inline bool fprobe_shared_with_kprobes(struct fprobe *fp)
+{
+	return (fp) ? fp->flags & FPROBE_FL_KPROBE_SHARED : false;
+}
+
+#ifdef CONFIG_FPROBE
+int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter);
+int register_fprobe_ips(struct fprobe *fp, unsigned long *addrs, int num);
+int register_fprobe_syms(struct fprobe *fp, const char **syms, int num);
+int unregister_fprobe(struct fprobe *fp);
+bool fprobe_is_registered(struct fprobe *fp);
+#else
+static inline int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter)
+{
+	return -EOPNOTSUPP;
+}
+static inline int register_fprobe_ips(struct fprobe *fp, unsigned long *addrs, int num)
+{
+	return -EOPNOTSUPP;
+}
+static inline int register_fprobe_syms(struct fprobe *fp, const char **syms, int num)
+{
+	return -EOPNOTSUPP;
+}
+static inline int unregister_fprobe(struct fprobe *fp)
+{
+	return -EOPNOTSUPP;
+}
+static inline bool fprobe_is_registered(struct fprobe *fp)
+{
+	return false;
+}
+#endif
+
+/**
+ * disable_fprobe() - Disable fprobe
+ * @fp: The fprobe to be disabled.
+ *
+ * This will soft-disable @fp. Note that this doesn't remove the ftrace
+ * hooks from the function entry.
+ */
+static inline void disable_fprobe(struct fprobe *fp)
+{
+	if (fp)
+		fp->flags |= FPROBE_FL_DISABLED;
+}
+
+/**
+ * enable_fprobe() - Enable fprobe
+ * @fp: The fprobe to be enabled.
+ *
+ * This will soft-enable @fp.
+ */
+static inline void enable_fprobe(struct fprobe *fp)
+{
+	if (fp)
+		fp->flags &= ~FPROBE_FL_DISABLED;
+}
+
+/* The entry data size is 4 bits (=16) * sizeof(long) in maximum */
+#define FPROBE_DATA_SIZE_BITS		4
+#define MAX_FPROBE_DATA_SIZE_WORD	((1L << FPROBE_DATA_SIZE_BITS) - 1)
+#define MAX_FPROBE_DATA_SIZE		(MAX_FPROBE_DATA_SIZE_WORD * sizeof(long))
+
+#endif