From cb16330d12741f6dae56aad5acf62f5be3a06c4e Mon Sep 17 00:00:00 2001
From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Date: Tue, 6 Jun 2023 21:39:55 +0900
Subject: fprobe: Pass return address to the handlers

Pass return address as 'ret_ip' to the fprobe entry and return handlers
so that the fprobe user handler can get the reutrn address without
analyzing arch-dependent pt_regs.

Link: https://lore.kernel.org/all/168507467664.913472.11642316698862778600.stgit@mhiramat.roam.corp.google.com/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 include/linux/fprobe.h  | 6 ++++--
 include/linux/rethook.h | 2 +-
 2 files changed, 5 insertions(+), 3 deletions(-)

(limited to 'include')

diff --git a/include/linux/fprobe.h b/include/linux/fprobe.h
index 47fefc7f363b..134f0f59ffa8 100644
--- a/include/linux/fprobe.h
+++ b/include/linux/fprobe.h
@@ -35,9 +35,11 @@ struct fprobe {
 	int			nr_maxactive;
 
 	int (*entry_handler)(struct fprobe *fp, unsigned long entry_ip,
-			     struct pt_regs *regs, void *entry_data);
+			     unsigned long ret_ip, struct pt_regs *regs,
+			     void *entry_data);
 	void (*exit_handler)(struct fprobe *fp, unsigned long entry_ip,
-			     struct pt_regs *regs, void *entry_data);
+			     unsigned long ret_ip, struct pt_regs *regs,
+			     void *entry_data);
 };
 
 /* This fprobe is soft-disabled. */
diff --git a/include/linux/rethook.h b/include/linux/rethook.h
index c8ac1e5afcd1..fdf26cd0e742 100644
--- a/include/linux/rethook.h
+++ b/include/linux/rethook.h
@@ -14,7 +14,7 @@
 
 struct rethook_node;
 
-typedef void (*rethook_handler_t) (struct rethook_node *, void *, struct pt_regs *);
+typedef void (*rethook_handler_t) (struct rethook_node *, void *, unsigned long, struct pt_regs *);
 
 /**
  * struct rethook - The rethook management data structure.
-- 
cgit v1.3.1


From 334e5519c3757019cc591d4539d5aca199bdb114 Mon Sep 17 00:00:00 2001
From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Date: Tue, 6 Jun 2023 21:39:55 +0900
Subject: tracing/probes: Add fprobe events for tracing function entry and
 exit.

Add fprobe events for tracing function entry and exit instead of kprobe
events. With this change, we can continue to trace function entry/exit
even if the CONFIG_KPROBES_ON_FTRACE is not available. Since
CONFIG_KPROBES_ON_FTRACE requires the CONFIG_DYNAMIC_FTRACE_WITH_REGS,
it is not available if the architecture only supports
CONFIG_DYNAMIC_FTRACE_WITH_ARGS. And that means kprobe events can not
probe function entry/exit effectively on such architecture.
But this can be solved if the dynamic events supports fprobe events.

The fprobe event is a new dynamic events which is only for the function
(symbol) entry and exit. This event accepts non register fetch arguments
so that user can trace the function arguments and return values.

The fprobe events syntax is here;

 f[:[GRP/][EVENT]] FUNCTION [FETCHARGS]
 f[MAXACTIVE][:[GRP/][EVENT]] FUNCTION%return [FETCHARGS]

E.g.

 # echo 'f vfs_read $arg1'  >> dynamic_events
 # echo 'f vfs_read%return $retval'  >> dynamic_events
 # cat dynamic_events
 f:fprobes/vfs_read__entry vfs_read arg1=$arg1
 f:fprobes/vfs_read__exit vfs_read%return arg1=$retval
 # echo 1 > events/fprobes/enable
 # head -n 20 trace | tail
 #           TASK-PID     CPU#  |||||  TIMESTAMP  FUNCTION
 #              | |         |   |||||     |         |
              sh-142     [005] ...1.   448.386420: vfs_read__entry: (vfs_read+0x4/0x340) arg1=0xffff888007f7c540
              sh-142     [005] .....   448.386436: vfs_read__exit: (ksys_read+0x75/0x100 <- vfs_read) arg1=0x1
              sh-142     [005] ...1.   448.386451: vfs_read__entry: (vfs_read+0x4/0x340) arg1=0xffff888007f7c540
              sh-142     [005] .....   448.386458: vfs_read__exit: (ksys_read+0x75/0x100 <- vfs_read) arg1=0x1
              sh-142     [005] ...1.   448.386469: vfs_read__entry: (vfs_read+0x4/0x340) arg1=0xffff888007f7c540
              sh-142     [005] .....   448.386476: vfs_read__exit: (ksys_read+0x75/0x100 <- vfs_read) arg1=0x1
              sh-142     [005] ...1.   448.602073: vfs_read__entry: (vfs_read+0x4/0x340) arg1=0xffff888007f7c540
              sh-142     [005] .....   448.602089: vfs_read__exit: (ksys_read+0x75/0x100 <- vfs_read) arg1=0x1

Link: https://lore.kernel.org/all/168507469754.913472.6112857614708350210.stgit@mhiramat.roam.corp.google.com/

Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/all/202302011530.7vm4O8Ro-lkp@intel.com/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 include/linux/fprobe.h                             |    5 +
 include/linux/trace_events.h                       |    3 +
 kernel/trace/Kconfig                               |   14 +
 kernel/trace/Makefile                              |    1 +
 kernel/trace/fprobe.c                              |   11 +-
 kernel/trace/trace.c                               |    8 +-
 kernel/trace/trace.h                               |   11 +
 kernel/trace/trace_fprobe.c                        | 1053 ++++++++++++++++++++
 kernel/trace/trace_kprobe.c                        |    2 +-
 kernel/trace/trace_probe.c                         |    4 +-
 kernel/trace/trace_probe.h                         |    3 +-
 .../ftrace/test.d/kprobe/kprobe_syntax_errors.tc   |    2 +-
 12 files changed, 1109 insertions(+), 8 deletions(-)
 create mode 100644 kernel/trace/trace_fprobe.c

(limited to 'include')

diff --git a/include/linux/fprobe.h b/include/linux/fprobe.h
index 134f0f59ffa8..3e03758151f4 100644
--- a/include/linux/fprobe.h
+++ b/include/linux/fprobe.h
@@ -66,6 +66,7 @@ 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)
 {
@@ -83,6 +84,10 @@ static inline int unregister_fprobe(struct fprobe *fp)
 {
 	return -EOPNOTSUPP;
 }
+static inline bool fprobe_is_registered(struct fprobe *fp)
+{
+	return false;
+}
 #endif
 
 /**
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 7c4a0b72334e..3930e676436c 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -318,6 +318,7 @@ enum {
 	TRACE_EVENT_FL_KPROBE_BIT,
 	TRACE_EVENT_FL_UPROBE_BIT,
 	TRACE_EVENT_FL_EPROBE_BIT,
+	TRACE_EVENT_FL_FPROBE_BIT,
 	TRACE_EVENT_FL_CUSTOM_BIT,
 };
 
@@ -332,6 +333,7 @@ enum {
  *  KPROBE        - Event is a kprobe
  *  UPROBE        - Event is a uprobe
  *  EPROBE        - Event is an event probe
+ *  FPROBE        - Event is an function probe
  *  CUSTOM        - Event is a custom event (to be attached to an exsiting tracepoint)
  *                   This is set when the custom event has not been attached
  *                   to a tracepoint yet, then it is cleared when it is.
@@ -346,6 +348,7 @@ enum {
 	TRACE_EVENT_FL_KPROBE		= (1 << TRACE_EVENT_FL_KPROBE_BIT),
 	TRACE_EVENT_FL_UPROBE		= (1 << TRACE_EVENT_FL_UPROBE_BIT),
 	TRACE_EVENT_FL_EPROBE		= (1 << TRACE_EVENT_FL_EPROBE_BIT),
+	TRACE_EVENT_FL_FPROBE		= (1 << TRACE_EVENT_FL_FPROBE_BIT),
 	TRACE_EVENT_FL_CUSTOM		= (1 << TRACE_EVENT_FL_CUSTOM_BIT),
 };
 
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 8cf97fa4a4b3..8e10a9453c96 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -650,6 +650,20 @@ config BLK_DEV_IO_TRACE
 
 	  If unsure, say N.
 
+config FPROBE_EVENTS
+	depends on FPROBE
+	depends on HAVE_REGS_AND_STACK_ACCESS_API
+	bool "Enable fprobe-based dynamic events"
+	select TRACING
+	select PROBE_EVENTS
+	select DYNAMIC_EVENTS
+	default y
+	help
+	  This allows user to add tracing events on the function entry and
+	  exit via ftrace interface. The syntax is same as the kprobe events
+	  and the kprobe events on function entry and exit will be
+	  transparently converted to this fprobe events.
+
 config KPROBE_EVENTS
 	depends on KPROBES
 	depends on HAVE_REGS_AND_STACK_ACCESS_API
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index c6651e16b557..64b61f67a403 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -104,6 +104,7 @@ obj-$(CONFIG_BOOTTIME_TRACING) += trace_boot.o
 obj-$(CONFIG_FTRACE_RECORD_RECURSION) += trace_recursion_record.o
 obj-$(CONFIG_FPROBE) += fprobe.o
 obj-$(CONFIG_RETHOOK) += rethook.o
+obj-$(CONFIG_FPROBE_EVENTS) += trace_fprobe.o
 
 obj-$(CONFIG_TRACEPOINT_BENCHMARK) += trace_benchmark.o
 obj-$(CONFIG_RV) += rv/
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index 32994815edf6..e4704ec26df7 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -348,6 +348,14 @@ int register_fprobe_syms(struct fprobe *fp, const char **syms, int num)
 }
 EXPORT_SYMBOL_GPL(register_fprobe_syms);
 
+bool fprobe_is_registered(struct fprobe *fp)
+{
+	if (!fp || (fp->ops.saved_func != fprobe_handler &&
+		    fp->ops.saved_func != fprobe_kprobe_handler))
+		return false;
+	return true;
+}
+
 /**
  * unregister_fprobe() - Unregister fprobe from ftrace
  * @fp: A fprobe data structure to be unregistered.
@@ -360,8 +368,7 @@ int unregister_fprobe(struct fprobe *fp)
 {
 	int ret;
 
-	if (!fp || (fp->ops.saved_func != fprobe_handler &&
-		    fp->ops.saved_func != fprobe_kprobe_handler))
+	if (!fprobe_is_registered(fp))
 		return -EINVAL;
 
 	/*
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 64a4dde073ef..755b0bf2e1ac 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5672,10 +5672,16 @@ static const char readme_msg[] =
 	"  uprobe_events\t\t- Create/append/remove/show the userspace dynamic events\n"
 	"\t\t\t  Write into this file to define/undefine new trace events.\n"
 #endif
-#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
+#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) || \
+    defined(CONFIG_FPROBE_EVENTS)
 	"\t  accepts: event-definitions (one definition per line)\n"
+#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
 	"\t   Format: p[:[<group>/][<event>]] <place> [<args>]\n"
 	"\t           r[maxactive][:[<group>/][<event>]] <place> [<args>]\n"
+#endif
+#ifdef CONFIG_FPROBE_EVENTS
+	"\t           f[:[<group>/][<event>]] <func-name>[%return] [<args>]\n"
+#endif
 #ifdef CONFIG_HIST_TRIGGERS
 	"\t           s:[synthetic/]<event> <field> [<field>]\n"
 #endif
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 79bdefe9261b..b5ab5479f9e3 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -148,6 +148,17 @@ struct kretprobe_trace_entry_head {
 	unsigned long		ret_ip;
 };
 
+struct fentry_trace_entry_head {
+	struct trace_entry	ent;
+	unsigned long		ip;
+};
+
+struct fexit_trace_entry_head {
+	struct trace_entry	ent;
+	unsigned long		func;
+	unsigned long		ret_ip;
+};
+
 #define TRACE_BUF_SIZE		1024
 
 struct trace_array;
diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
new file mode 100644
index 000000000000..48dbbc72b7dd
--- /dev/null
+++ b/kernel/trace/trace_fprobe.c
@@ -0,0 +1,1053 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Fprobe-based tracing events
+ * Copyright (C) 2022 Google LLC.
+ */
+#define pr_fmt(fmt)	"trace_fprobe: " fmt
+
+#include <linux/fprobe.h>
+#include <linux/module.h>
+#include <linux/rculist.h>
+#include <linux/security.h>
+#include <linux/uaccess.h>
+
+#include "trace_dynevent.h"
+#include "trace_probe.h"
+#include "trace_probe_kernel.h"
+#include "trace_probe_tmpl.h"
+
+#define FPROBE_EVENT_SYSTEM "fprobes"
+#define RETHOOK_MAXACTIVE_MAX 4096
+
+static int trace_fprobe_create(const char *raw_command);
+static int trace_fprobe_show(struct seq_file *m, struct dyn_event *ev);
+static int trace_fprobe_release(struct dyn_event *ev);
+static bool trace_fprobe_is_busy(struct dyn_event *ev);
+static bool trace_fprobe_match(const char *system, const char *event,
+			int argc, const char **argv, struct dyn_event *ev);
+
+static struct dyn_event_operations trace_fprobe_ops = {
+	.create = trace_fprobe_create,
+	.show = trace_fprobe_show,
+	.is_busy = trace_fprobe_is_busy,
+	.free = trace_fprobe_release,
+	.match = trace_fprobe_match,
+};
+
+/*
+ * Fprobe event core functions
+ */
+struct trace_fprobe {
+	struct dyn_event	devent;
+	struct fprobe		fp;
+	const char		*symbol;
+	struct trace_probe	tp;
+};
+
+static bool is_trace_fprobe(struct dyn_event *ev)
+{
+	return ev->ops == &trace_fprobe_ops;
+}
+
+static struct trace_fprobe *to_trace_fprobe(struct dyn_event *ev)
+{
+	return container_of(ev, struct trace_fprobe, devent);
+}
+
+/**
+ * for_each_trace_fprobe - iterate over the trace_fprobe list
+ * @pos:	the struct trace_fprobe * for each entry
+ * @dpos:	the struct dyn_event * to use as a loop cursor
+ */
+#define for_each_trace_fprobe(pos, dpos)	\
+	for_each_dyn_event(dpos)		\
+		if (is_trace_fprobe(dpos) && (pos = to_trace_fprobe(dpos)))
+
+static bool trace_fprobe_is_return(struct trace_fprobe *tf)
+{
+	return tf->fp.exit_handler != NULL;
+}
+
+static const char *trace_fprobe_symbol(struct trace_fprobe *tf)
+{
+	return tf->symbol ? tf->symbol : "unknown";
+}
+
+static bool trace_fprobe_is_busy(struct dyn_event *ev)
+{
+	struct trace_fprobe *tf = to_trace_fprobe(ev);
+
+	return trace_probe_is_enabled(&tf->tp);
+}
+
+static bool trace_fprobe_match_command_head(struct trace_fprobe *tf,
+					    int argc, const char **argv)
+{
+	char buf[MAX_ARGSTR_LEN + 1];
+
+	if (!argc)
+		return true;
+
+	snprintf(buf, sizeof(buf), "%s", trace_fprobe_symbol(tf));
+	if (strcmp(buf, argv[0]))
+		return false;
+	argc--; argv++;
+
+	return trace_probe_match_command_args(&tf->tp, argc, argv);
+}
+
+static bool trace_fprobe_match(const char *system, const char *event,
+			int argc, const char **argv, struct dyn_event *ev)
+{
+	struct trace_fprobe *tf = to_trace_fprobe(ev);
+
+	if (event[0] != '\0' && strcmp(trace_probe_name(&tf->tp), event))
+		return false;
+
+	if (system && strcmp(trace_probe_group_name(&tf->tp), system))
+		return false;
+
+	return trace_fprobe_match_command_head(tf, argc, argv);
+}
+
+static bool trace_fprobe_is_registered(struct trace_fprobe *tf)
+{
+	return fprobe_is_registered(&tf->fp);
+}
+
+/*
+ * Note that we don't verify the fetch_insn code, since it does not come
+ * from user space.
+ */
+static int
+process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
+		   void *base)
+{
+	struct pt_regs *regs = rec;
+	unsigned long val;
+	int ret;
+
+retry:
+	/* 1st stage: get value from context */
+	switch (code->op) {
+	case FETCH_OP_STACK:
+		val = regs_get_kernel_stack_nth(regs, code->param);
+		break;
+	case FETCH_OP_STACKP:
+		val = kernel_stack_pointer(regs);
+		break;
+	case FETCH_OP_RETVAL:
+		val = regs_return_value(regs);
+		break;
+#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
+	case FETCH_OP_ARG:
+		val = regs_get_kernel_argument(regs, code->param);
+		break;
+#endif
+	case FETCH_NOP_SYMBOL:	/* Ignore a place holder */
+		code++;
+		goto retry;
+	default:
+		ret = process_common_fetch_insn(code, &val);
+		if (ret < 0)
+			return ret;
+	}
+	code++;
+
+	return process_fetch_insn_bottom(code, val, dest, base);
+}
+NOKPROBE_SYMBOL(process_fetch_insn)
+
+/* function entry handler */
+static nokprobe_inline void
+__fentry_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
+		    struct pt_regs *regs,
+		    struct trace_event_file *trace_file)
+{
+	struct fentry_trace_entry_head *entry;
+	struct trace_event_call *call = trace_probe_event_call(&tf->tp);
+	struct trace_event_buffer fbuffer;
+	int dsize;
+
+	if (WARN_ON_ONCE(call != trace_file->event_call))
+		return;
+
+	if (trace_trigger_soft_disabled(trace_file))
+		return;
+
+	dsize = __get_data_size(&tf->tp, regs);
+
+	entry = trace_event_buffer_reserve(&fbuffer, trace_file,
+					   sizeof(*entry) + tf->tp.size + dsize);
+	if (!entry)
+		return;
+
+	fbuffer.regs = regs;
+	entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
+	entry->ip = entry_ip;
+	store_trace_args(&entry[1], &tf->tp, regs, sizeof(*entry), dsize);
+
+	trace_event_buffer_commit(&fbuffer);
+}
+
+static void
+fentry_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
+		  struct pt_regs *regs)
+{
+	struct event_file_link *link;
+
+	trace_probe_for_each_link_rcu(link, &tf->tp)
+		__fentry_trace_func(tf, entry_ip, regs, link->file);
+}
+NOKPROBE_SYMBOL(fentry_trace_func);
+
+/* Kretprobe handler */
+static nokprobe_inline void
+__fexit_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
+		   unsigned long ret_ip, struct pt_regs *regs,
+		   struct trace_event_file *trace_file)
+{
+	struct fexit_trace_entry_head *entry;
+	struct trace_event_buffer fbuffer;
+	struct trace_event_call *call = trace_probe_event_call(&tf->tp);
+	int dsize;
+
+	if (WARN_ON_ONCE(call != trace_file->event_call))
+		return;
+
+	if (trace_trigger_soft_disabled(trace_file))
+		return;
+
+	dsize = __get_data_size(&tf->tp, regs);
+
+	entry = trace_event_buffer_reserve(&fbuffer, trace_file,
+					   sizeof(*entry) + tf->tp.size + dsize);
+	if (!entry)
+		return;
+
+	fbuffer.regs = regs;
+	entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
+	entry->func = entry_ip;
+	entry->ret_ip = ret_ip;
+	store_trace_args(&entry[1], &tf->tp, regs, sizeof(*entry), dsize);
+
+	trace_event_buffer_commit(&fbuffer);
+}
+
+static void
+fexit_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
+		 unsigned long ret_ip, struct pt_regs *regs)
+{
+	struct event_file_link *link;
+
+	trace_probe_for_each_link_rcu(link, &tf->tp)
+		__fexit_trace_func(tf, entry_ip, ret_ip, regs, link->file);
+}
+NOKPROBE_SYMBOL(fexit_trace_func);
+
+#ifdef CONFIG_PERF_EVENTS
+
+static int fentry_perf_func(struct trace_fprobe *tf, unsigned long entry_ip,
+			    struct pt_regs *regs)
+{
+	struct trace_event_call *call = trace_probe_event_call(&tf->tp);
+	struct fentry_trace_entry_head *entry;
+	struct hlist_head *head;
+	int size, __size, dsize;
+	int rctx;
+
+	head = this_cpu_ptr(call->perf_events);
+	if (hlist_empty(head))
+		return 0;
+
+	dsize = __get_data_size(&tf->tp, regs);
+	__size = sizeof(*entry) + tf->tp.size + dsize;
+	size = ALIGN(__size + sizeof(u32), sizeof(u64));
+	size -= sizeof(u32);
+
+	entry = perf_trace_buf_alloc(size, NULL, &rctx);
+	if (!entry)
+		return 0;
+
+	entry->ip = entry_ip;
+	memset(&entry[1], 0, dsize);
+	store_trace_args(&entry[1], &tf->tp, regs, sizeof(*entry), dsize);
+	perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
+			      head, NULL);
+	return 0;
+}
+NOKPROBE_SYMBOL(fentry_perf_func);
+
+static void
+fexit_perf_func(struct trace_fprobe *tf, unsigned long entry_ip,
+		unsigned long ret_ip, struct pt_regs *regs)
+{
+	struct trace_event_call *call = trace_probe_event_call(&tf->tp);
+	struct fexit_trace_entry_head *entry;
+	struct hlist_head *head;
+	int size, __size, dsize;
+	int rctx;
+
+	head = this_cpu_ptr(call->perf_events);
+	if (hlist_empty(head))
+		return;
+
+	dsize = __get_data_size(&tf->tp, regs);
+	__size = sizeof(*entry) + tf->tp.size + dsize;
+	size = ALIGN(__size + sizeof(u32), sizeof(u64));
+	size -= sizeof(u32);
+
+	entry = perf_trace_buf_alloc(size, NULL, &rctx);
+	if (!entry)
+		return;
+
+	entry->func = entry_ip;
+	entry->ret_ip = ret_ip;
+	store_trace_args(&entry[1], &tf->tp, regs, sizeof(*entry), dsize);
+	perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
+			      head, NULL);
+}
+NOKPROBE_SYMBOL(fexit_perf_func);
+#endif	/* CONFIG_PERF_EVENTS */
+
+static int fentry_dispatcher(struct fprobe *fp, unsigned long entry_ip,
+			     unsigned long ret_ip, struct pt_regs *regs,
+			     void *entry_data)
+{
+	struct trace_fprobe *tf = container_of(fp, struct trace_fprobe, fp);
+	int ret = 0;
+
+	if (trace_probe_test_flag(&tf->tp, TP_FLAG_TRACE))
+		fentry_trace_func(tf, entry_ip, regs);
+#ifdef CONFIG_PERF_EVENTS
+	if (trace_probe_test_flag(&tf->tp, TP_FLAG_PROFILE))
+		ret = fentry_perf_func(tf, entry_ip, regs);
+#endif
+	return ret;
+}
+NOKPROBE_SYMBOL(fentry_dispatcher);
+
+static void fexit_dispatcher(struct fprobe *fp, unsigned long entry_ip,
+			     unsigned long ret_ip, struct pt_regs *regs,
+			     void *entry_data)
+{
+	struct trace_fprobe *tf = container_of(fp, struct trace_fprobe, fp);
+
+	if (trace_probe_test_flag(&tf->tp, TP_FLAG_TRACE))
+		fexit_trace_func(tf, entry_ip, ret_ip, regs);
+#ifdef CONFIG_PERF_EVENTS
+	if (trace_probe_test_flag(&tf->tp, TP_FLAG_PROFILE))
+		fexit_perf_func(tf, entry_ip, ret_ip, regs);
+#endif
+}
+NOKPROBE_SYMBOL(fexit_dispatcher);
+
+static void free_trace_fprobe(struct trace_fprobe *tf)
+{
+	if (tf) {
+		trace_probe_cleanup(&tf->tp);
+		kfree(tf->symbol);
+		kfree(tf);
+	}
+}
+
+/*
+ * Allocate new trace_probe and initialize it (including fprobe).
+ */
+static struct trace_fprobe *alloc_trace_fprobe(const char *group,
+					       const char *event,
+					       const char *symbol,
+					       int maxactive,
+					       int nargs, bool is_return)
+{
+	struct trace_fprobe *tf;
+	int ret = -ENOMEM;
+
+	tf = kzalloc(struct_size(tf, tp.args, nargs), GFP_KERNEL);
+	if (!tf)
+		return ERR_PTR(ret);
+
+	tf->symbol = kstrdup(symbol, GFP_KERNEL);
+	if (!tf->symbol)
+		goto error;
+
+	if (is_return)
+		tf->fp.exit_handler = fexit_dispatcher;
+	else
+		tf->fp.entry_handler = fentry_dispatcher;
+
+	tf->fp.nr_maxactive = maxactive;
+
+	ret = trace_probe_init(&tf->tp, event, group, false);
+	if (ret < 0)
+		goto error;
+
+	dyn_event_init(&tf->devent, &trace_fprobe_ops);
+	return tf;
+error:
+	free_trace_fprobe(tf);
+	return ERR_PTR(ret);
+}
+
+static struct trace_fprobe *find_trace_fprobe(const char *event,
+					      const char *group)
+{
+	struct dyn_event *pos;
+	struct trace_fprobe *tf;
+
+	for_each_trace_fprobe(tf, pos)
+		if (strcmp(trace_probe_name(&tf->tp), event) == 0 &&
+		    strcmp(trace_probe_group_name(&tf->tp), group) == 0)
+			return tf;
+	return NULL;
+}
+
+static inline int __enable_trace_fprobe(struct trace_fprobe *tf)
+{
+	if (trace_fprobe_is_registered(tf))
+		enable_fprobe(&tf->fp);
+
+	return 0;
+}
+
+static void __disable_trace_fprobe(struct trace_probe *tp)
+{
+	struct trace_fprobe *tf;
+
+	list_for_each_entry(tf, trace_probe_probe_list(tp), tp.list) {
+		if (!trace_fprobe_is_registered(tf))
+			continue;
+		disable_fprobe(&tf->fp);
+	}
+}
+
+/*
+ * Enable trace_probe
+ * if the file is NULL, enable "perf" handler, or enable "trace" handler.
+ */
+static int enable_trace_fprobe(struct trace_event_call *call,
+			       struct trace_event_file *file)
+{
+	struct trace_probe *tp;
+	struct trace_fprobe *tf;
+	bool enabled;
+	int ret = 0;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENODEV;
+	enabled = trace_probe_is_enabled(tp);
+
+	/* This also changes "enabled" state */
+	if (file) {
+		ret = trace_probe_add_file(tp, file);
+		if (ret)
+			return ret;
+	} else
+		trace_probe_set_flag(tp, TP_FLAG_PROFILE);
+
+	if (!enabled) {
+		list_for_each_entry(tf, trace_probe_probe_list(tp), tp.list) {
+			/* TODO: check the fprobe is gone */
+			__enable_trace_fprobe(tf);
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Disable trace_probe
+ * if the file is NULL, disable "perf" handler, or disable "trace" handler.
+ */
+static int disable_trace_fprobe(struct trace_event_call *call,
+				struct trace_event_file *file)
+{
+	struct trace_probe *tp;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENODEV;
+
+	if (file) {
+		if (!trace_probe_get_file_link(tp, file))
+			return -ENOENT;
+		if (!trace_probe_has_single_file(tp))
+			goto out;
+		trace_probe_clear_flag(tp, TP_FLAG_TRACE);
+	} else
+		trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
+
+	if (!trace_probe_is_enabled(tp))
+		__disable_trace_fprobe(tp);
+
+ out:
+	if (file)
+		/*
+		 * Synchronization is done in below function. For perf event,
+		 * file == NULL and perf_trace_event_unreg() calls
+		 * tracepoint_synchronize_unregister() to ensure synchronize
+		 * event. We don't need to care about it.
+		 */
+		trace_probe_remove_file(tp, file);
+
+	return 0;
+}
+
+/* Event entry printers */
+static enum print_line_t
+print_fentry_event(struct trace_iterator *iter, int flags,
+		   struct trace_event *event)
+{
+	struct fentry_trace_entry_head *field;
+	struct trace_seq *s = &iter->seq;
+	struct trace_probe *tp;
+
+	field = (struct fentry_trace_entry_head *)iter->ent;
+	tp = trace_probe_primary_from_call(
+		container_of(event, struct trace_event_call, event));
+	if (WARN_ON_ONCE(!tp))
+		goto out;
+
+	trace_seq_printf(s, "%s: (", trace_probe_name(tp));
+
+	if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
+		goto out;
+
+	trace_seq_putc(s, ')');
+
+	if (trace_probe_print_args(s, tp->args, tp->nr_args,
+			     (u8 *)&field[1], field) < 0)
+		goto out;
+
+	trace_seq_putc(s, '\n');
+ out:
+	return trace_handle_return(s);
+}
+
+static enum print_line_t
+print_fexit_event(struct trace_iterator *iter, int flags,
+		  struct trace_event *event)
+{
+	struct fexit_trace_entry_head *field;
+	struct trace_seq *s = &iter->seq;
+	struct trace_probe *tp;
+
+	field = (struct fexit_trace_entry_head *)iter->ent;
+	tp = trace_probe_primary_from_call(
+		container_of(event, struct trace_event_call, event));
+	if (WARN_ON_ONCE(!tp))
+		goto out;
+
+	trace_seq_printf(s, "%s: (", trace_probe_name(tp));
+
+	if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
+		goto out;
+
+	trace_seq_puts(s, " <- ");
+
+	if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
+		goto out;
+
+	trace_seq_putc(s, ')');
+
+	if (trace_probe_print_args(s, tp->args, tp->nr_args,
+			     (u8 *)&field[1], field) < 0)
+		goto out;
+
+	trace_seq_putc(s, '\n');
+
+ out:
+	return trace_handle_return(s);
+}
+
+static int fentry_event_define_fields(struct trace_event_call *event_call)
+{
+	int ret;
+	struct fentry_trace_entry_head field;
+	struct trace_probe *tp;
+
+	tp = trace_probe_primary_from_call(event_call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENOENT;
+
+	DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
+
+	return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
+}
+
+static int fexit_event_define_fields(struct trace_event_call *event_call)
+{
+	int ret;
+	struct fexit_trace_entry_head field;
+	struct trace_probe *tp;
+
+	tp = trace_probe_primary_from_call(event_call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENOENT;
+
+	DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
+	DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
+
+	return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
+}
+
+static struct trace_event_functions fentry_funcs = {
+	.trace		= print_fentry_event
+};
+
+static struct trace_event_functions fexit_funcs = {
+	.trace		= print_fexit_event
+};
+
+static struct trace_event_fields fentry_fields_array[] = {
+	{ .type = TRACE_FUNCTION_TYPE,
+	  .define_fields = fentry_event_define_fields },
+	{}
+};
+
+static struct trace_event_fields fexit_fields_array[] = {
+	{ .type = TRACE_FUNCTION_TYPE,
+	  .define_fields = fexit_event_define_fields },
+	{}
+};
+
+static int fprobe_register(struct trace_event_call *event,
+			   enum trace_reg type, void *data);
+
+static inline void init_trace_event_call(struct trace_fprobe *tf)
+{
+	struct trace_event_call *call = trace_probe_event_call(&tf->tp);
+
+	if (trace_fprobe_is_return(tf)) {
+		call->event.funcs = &fexit_funcs;
+		call->class->fields_array = fexit_fields_array;
+	} else {
+		call->event.funcs = &fentry_funcs;
+		call->class->fields_array = fentry_fields_array;
+	}
+
+	call->flags = TRACE_EVENT_FL_FPROBE;
+	call->class->reg = fprobe_register;
+}
+
+static int register_fprobe_event(struct trace_fprobe *tf)
+{
+	init_trace_event_call(tf);
+
+	return trace_probe_register_event_call(&tf->tp);
+}
+
+static int unregister_fprobe_event(struct trace_fprobe *tf)
+{
+	return trace_probe_unregister_event_call(&tf->tp);
+}
+
+/* Internal register function - just handle fprobe and flags */
+static int __register_trace_fprobe(struct trace_fprobe *tf)
+{
+	int i, ret;
+
+	/* Should we need new LOCKDOWN flag for fprobe? */
+	ret = security_locked_down(LOCKDOWN_KPROBES);
+	if (ret)
+		return ret;
+
+	if (trace_fprobe_is_registered(tf))
+		return -EINVAL;
+
+	for (i = 0; i < tf->tp.nr_args; i++) {
+		ret = traceprobe_update_arg(&tf->tp.args[i]);
+		if (ret)
+			return ret;
+	}
+
+	/* Set/clear disabled flag according to tp->flag */
+	if (trace_probe_is_enabled(&tf->tp))
+		tf->fp.flags &= ~FPROBE_FL_DISABLED;
+	else
+		tf->fp.flags |= FPROBE_FL_DISABLED;
+
+	/* TODO: handle filter, nofilter or symbol list */
+	return register_fprobe(&tf->fp, tf->symbol, NULL);
+}
+
+/* Internal unregister function - just handle fprobe and flags */
+static void __unregister_trace_fprobe(struct trace_fprobe *tf)
+{
+	if (trace_fprobe_is_registered(tf)) {
+		unregister_fprobe(&tf->fp);
+		memset(&tf->fp, 0, sizeof(tf->fp));
+	}
+}
+
+/* TODO: make this trace_*probe common function */
+/* Unregister a trace_probe and probe_event */
+static int unregister_trace_fprobe(struct trace_fprobe *tf)
+{
+	/* If other probes are on the event, just unregister fprobe */
+	if (trace_probe_has_sibling(&tf->tp))
+		goto unreg;
+
+	/* Enabled event can not be unregistered */
+	if (trace_probe_is_enabled(&tf->tp))
+		return -EBUSY;
+
+	/* If there's a reference to the dynamic event */
+	if (trace_event_dyn_busy(trace_probe_event_call(&tf->tp)))
+		return -EBUSY;
+
+	/* Will fail if probe is being used by ftrace or perf */
+	if (unregister_fprobe_event(tf))
+		return -EBUSY;
+
+unreg:
+	__unregister_trace_fprobe(tf);
+	dyn_event_remove(&tf->devent);
+	trace_probe_unlink(&tf->tp);
+
+	return 0;
+}
+
+static bool trace_fprobe_has_same_fprobe(struct trace_fprobe *orig,
+					 struct trace_fprobe *comp)
+{
+	struct trace_probe_event *tpe = orig->tp.event;
+	int i;
+
+	list_for_each_entry(orig, &tpe->probes, tp.list) {
+		if (strcmp(trace_fprobe_symbol(orig),
+			   trace_fprobe_symbol(comp)))
+			continue;
+
+		/*
+		 * trace_probe_compare_arg_type() ensured that nr_args and
+		 * each argument name and type are same. Let's compare comm.
+		 */
+		for (i = 0; i < orig->tp.nr_args; i++) {
+			if (strcmp(orig->tp.args[i].comm,
+				   comp->tp.args[i].comm))
+				break;
+		}
+
+		if (i == orig->tp.nr_args)
+			return true;
+	}
+
+	return false;
+}
+
+static int append_trace_fprobe(struct trace_fprobe *tf, struct trace_fprobe *to)
+{
+	int ret;
+
+	if (trace_fprobe_is_return(tf) != trace_fprobe_is_return(to)) {
+		trace_probe_log_set_index(0);
+		trace_probe_log_err(0, DIFF_PROBE_TYPE);
+		return -EEXIST;
+	}
+	ret = trace_probe_compare_arg_type(&tf->tp, &to->tp);
+	if (ret) {
+		/* Note that argument starts index = 2 */
+		trace_probe_log_set_index(ret + 1);
+		trace_probe_log_err(0, DIFF_ARG_TYPE);
+		return -EEXIST;
+	}
+	if (trace_fprobe_has_same_fprobe(to, tf)) {
+		trace_probe_log_set_index(0);
+		trace_probe_log_err(0, SAME_PROBE);
+		return -EEXIST;
+	}
+
+	/* Append to existing event */
+	ret = trace_probe_append(&tf->tp, &to->tp);
+	if (ret)
+		return ret;
+
+	ret = __register_trace_fprobe(tf);
+	if (ret)
+		trace_probe_unlink(&tf->tp);
+	else
+		dyn_event_add(&tf->devent, trace_probe_event_call(&tf->tp));
+
+	return ret;
+}
+
+/* Register a trace_probe and probe_event */
+static int register_trace_fprobe(struct trace_fprobe *tf)
+{
+	struct trace_fprobe *old_tf;
+	int ret;
+
+	mutex_lock(&event_mutex);
+
+	old_tf = find_trace_fprobe(trace_probe_name(&tf->tp),
+				   trace_probe_group_name(&tf->tp));
+	if (old_tf) {
+		ret = append_trace_fprobe(tf, old_tf);
+		goto end;
+	}
+
+	/* Register new event */
+	ret = register_fprobe_event(tf);
+	if (ret) {
+		if (ret == -EEXIST) {
+			trace_probe_log_set_index(0);
+			trace_probe_log_err(0, EVENT_EXIST);
+		} else
+			pr_warn("Failed to register probe event(%d)\n", ret);
+		goto end;
+	}
+
+	/* Register fprobe */
+	ret = __register_trace_fprobe(tf);
+	if (ret < 0)
+		unregister_fprobe_event(tf);
+	else
+		dyn_event_add(&tf->devent, trace_probe_event_call(&tf->tp));
+
+end:
+	mutex_unlock(&event_mutex);
+	return ret;
+}
+
+static int __trace_fprobe_create(int argc, const char *argv[])
+{
+	/*
+	 * Argument syntax:
+	 *  - Add fentry probe:
+	 *      f[:[GRP/][EVENT]] [MOD:]KSYM [FETCHARGS]
+	 *  - Add fexit probe:
+	 *      f[N][:[GRP/][EVENT]] [MOD:]KSYM%return [FETCHARGS]
+	 *
+	 * Fetch args:
+	 *  $retval	: fetch return value
+	 *  $stack	: fetch stack address
+	 *  $stackN	: fetch Nth entry of stack (N:0-)
+	 *  $argN	: fetch Nth argument (N:1-)
+	 *  $comm       : fetch current task comm
+	 *  @ADDR	: fetch memory at ADDR (ADDR should be in kernel)
+	 *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
+	 * Dereferencing memory fetch:
+	 *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
+	 * Alias name of args:
+	 *  NAME=FETCHARG : set NAME as alias of FETCHARG.
+	 * Type of args:
+	 *  FETCHARG:TYPE : use TYPE instead of unsigned long.
+	 */
+	struct trace_fprobe *tf = NULL;
+	int i, len, ret = 0;
+	bool is_return = false;
+	char *symbol = NULL, *tmp = NULL;
+	const char *event = NULL, *group = FPROBE_EVENT_SYSTEM;
+	int maxactive = 0;
+	char buf[MAX_EVENT_NAME_LEN];
+	char gbuf[MAX_EVENT_NAME_LEN];
+	unsigned int flags = TPARG_FL_KERNEL | TPARG_FL_FPROBE;
+
+	if (argv[0][0] != 'f' || argc < 2)
+		return -ECANCELED;
+
+	trace_probe_log_init("trace_fprobe", argc, argv);
+
+	event = strchr(&argv[0][1], ':');
+	if (event)
+		event++;
+
+	if (isdigit(argv[0][1])) {
+		if (event)
+			len = event - &argv[0][1] - 1;
+		else
+			len = strlen(&argv[0][1]);
+		if (len > MAX_EVENT_NAME_LEN - 1) {
+			trace_probe_log_err(1, BAD_MAXACT);
+			goto parse_error;
+		}
+		memcpy(buf, &argv[0][1], len);
+		buf[len] = '\0';
+		ret = kstrtouint(buf, 0, &maxactive);
+		if (ret || !maxactive) {
+			trace_probe_log_err(1, BAD_MAXACT);
+			goto parse_error;
+		}
+		/* fprobe rethook instances are iterated over via a list. The
+		 * maximum should stay reasonable.
+		 */
+		if (maxactive > RETHOOK_MAXACTIVE_MAX) {
+			trace_probe_log_err(1, MAXACT_TOO_BIG);
+			goto parse_error;
+		}
+	}
+
+	trace_probe_log_set_index(1);
+
+	/* a symbol specified */
+	symbol = kstrdup(argv[1], GFP_KERNEL);
+	if (!symbol)
+		return -ENOMEM;
+
+	tmp = strchr(symbol, '%');
+	if (tmp) {
+		if (!strcmp(tmp, "%return")) {
+			*tmp = '\0';
+			is_return = true;
+		} else {
+			trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
+			goto parse_error;
+		}
+	}
+	if (!is_return && maxactive) {
+		trace_probe_log_set_index(0);
+		trace_probe_log_err(1, BAD_MAXACT_TYPE);
+		goto parse_error;
+	}
+
+	if (is_return)
+		flags |= TPARG_FL_RETURN;
+	else
+		flags |= TPARG_FL_FENTRY;
+
+	trace_probe_log_set_index(0);
+	if (event) {
+		ret = traceprobe_parse_event_name(&event, &group, gbuf,
+						  event - argv[0]);
+		if (ret)
+			goto parse_error;
+	}
+
+	if (!event) {
+		/* Make a new event name */
+		snprintf(buf, MAX_EVENT_NAME_LEN, "%s__%s", symbol,
+			 is_return ? "exit" : "entry");
+		sanitize_event_name(buf);
+		event = buf;
+	}
+
+	/* setup a probe */
+	tf = alloc_trace_fprobe(group, event, symbol, maxactive,
+				argc - 2, is_return);
+	if (IS_ERR(tf)) {
+		ret = PTR_ERR(tf);
+		/* This must return -ENOMEM, else there is a bug */
+		WARN_ON_ONCE(ret != -ENOMEM);
+		goto out;	/* We know tf is not allocated */
+	}
+	argc -= 2; argv += 2;
+
+	/* parse arguments */
+	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
+		trace_probe_log_set_index(i + 2);
+		ret = traceprobe_parse_probe_arg(&tf->tp, i, argv[i], flags);
+		if (ret)
+			goto error;	/* This can be -ENOMEM */
+	}
+
+	ret = traceprobe_set_print_fmt(&tf->tp,
+			is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL);
+	if (ret < 0)
+		goto error;
+
+	ret = register_trace_fprobe(tf);
+	if (ret) {
+		trace_probe_log_set_index(1);
+		if (ret == -EILSEQ)
+			trace_probe_log_err(0, BAD_INSN_BNDRY);
+		else if (ret == -ENOENT)
+			trace_probe_log_err(0, BAD_PROBE_ADDR);
+		else if (ret != -ENOMEM && ret != -EEXIST)
+			trace_probe_log_err(0, FAIL_REG_PROBE);
+		goto error;
+	}
+
+out:
+	trace_probe_log_clear();
+	kfree(symbol);
+	return ret;
+
+parse_error:
+	ret = -EINVAL;
+error:
+	free_trace_fprobe(tf);
+	goto out;
+}
+
+static int trace_fprobe_create(const char *raw_command)
+{
+	return trace_probe_create(raw_command, __trace_fprobe_create);
+}
+
+static int trace_fprobe_release(struct dyn_event *ev)
+{
+	struct trace_fprobe *tf = to_trace_fprobe(ev);
+	int ret = unregister_trace_fprobe(tf);
+
+	if (!ret)
+		free_trace_fprobe(tf);
+	return ret;
+}
+
+static int trace_fprobe_show(struct seq_file *m, struct dyn_event *ev)
+{
+	struct trace_fprobe *tf = to_trace_fprobe(ev);
+	int i;
+
+	seq_putc(m, 'f');
+	if (trace_fprobe_is_return(tf) && tf->fp.nr_maxactive)
+		seq_printf(m, "%d", tf->fp.nr_maxactive);
+	seq_printf(m, ":%s/%s", trace_probe_group_name(&tf->tp),
+				trace_probe_name(&tf->tp));
+
+	seq_printf(m, " %s%s", trace_fprobe_symbol(tf),
+			       trace_fprobe_is_return(tf) ? "%return" : "");
+
+	for (i = 0; i < tf->tp.nr_args; i++)
+		seq_printf(m, " %s=%s", tf->tp.args[i].name, tf->tp.args[i].comm);
+	seq_putc(m, '\n');
+
+	return 0;
+}
+
+/*
+ * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
+ */
+static int fprobe_register(struct trace_event_call *event,
+			   enum trace_reg type, void *data)
+{
+	struct trace_event_file *file = data;
+
+	switch (type) {
+	case TRACE_REG_REGISTER:
+		return enable_trace_fprobe(event, file);
+	case TRACE_REG_UNREGISTER:
+		return disable_trace_fprobe(event, file);
+
+#ifdef CONFIG_PERF_EVENTS
+	case TRACE_REG_PERF_REGISTER:
+		return enable_trace_fprobe(event, NULL);
+	case TRACE_REG_PERF_UNREGISTER:
+		return disable_trace_fprobe(event, NULL);
+	case TRACE_REG_PERF_OPEN:
+	case TRACE_REG_PERF_CLOSE:
+	case TRACE_REG_PERF_ADD:
+	case TRACE_REG_PERF_DEL:
+		return 0;
+#endif
+	}
+	return 0;
+}
+
+/*
+ * Register dynevent at core_initcall. This allows kernel to setup fprobe
+ * events in postcore_initcall without tracefs.
+ */
+static __init int init_fprobe_trace_early(void)
+{
+	int ret;
+
+	ret = dyn_event_register(&trace_fprobe_ops);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+core_initcall(init_fprobe_trace_early);
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 867ffb7ee31d..b7a4409674b3 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -764,7 +764,7 @@ static int __trace_kprobe_create(int argc, const char *argv[])
 
 	if (isdigit(argv[0][1])) {
 		if (!is_return) {
-			trace_probe_log_err(1, MAXACT_NO_KPROBE);
+			trace_probe_log_err(1, BAD_MAXACT_TYPE);
 			goto parse_error;
 		}
 		if (event)
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 2d2616678295..c39860fb2e41 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -393,8 +393,8 @@ parse_probe_arg(char *arg, const struct fetch_type *type,
 		break;
 
 	case '%':	/* named register */
-		if (flags & TPARG_FL_TPOINT) {
-			/* eprobes do not handle registers */
+		if (flags & (TPARG_FL_TPOINT | TPARG_FL_FPROBE)) {
+			/* eprobe and fprobe do not handle registers */
 			trace_probe_log_err(offs, BAD_VAR);
 			break;
 		}
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 5df59714f9f5..8f4f23e8b234 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -367,6 +367,7 @@ int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_a
 #define TPARG_FL_FENTRY BIT(2)
 #define TPARG_FL_TPOINT BIT(3)
 #define TPARG_FL_USER   BIT(4)
+#define TPARG_FL_FPROBE BIT(5)
 #define TPARG_FL_MASK	GENMASK(4, 0)
 
 extern int traceprobe_parse_probe_arg(struct trace_probe *tp, int i,
@@ -409,7 +410,7 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 	C(REFCNT_OPEN_BRACE,	"Reference counter brace is not closed"), \
 	C(BAD_REFCNT_SUFFIX,	"Reference counter has wrong suffix"),	\
 	C(BAD_UPROBE_OFFS,	"Invalid uprobe offset"),		\
-	C(MAXACT_NO_KPROBE,	"Maxactive is not for kprobe"),		\
+	C(BAD_MAXACT_TYPE,	"Maxactive is only for function exit"),	\
 	C(BAD_MAXACT,		"Invalid maxactive number"),		\
 	C(MAXACT_TOO_BIG,	"Maxactive is too big"),		\
 	C(BAD_PROBE_ADDR,	"Invalid probed address or symbol"),	\
diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc
index 9e85d3019ff0..97c08867490a 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc
@@ -8,7 +8,7 @@ check_error() { # command-with-error-pos-by-^
 }
 
 if grep -q 'r\[maxactive\]' README; then
-check_error 'p^100 vfs_read'		# MAXACT_NO_KPROBE
+check_error 'p^100 vfs_read'		# BAD_MAXACT_TYPE
 check_error 'r^1a111 vfs_read'		# BAD_MAXACT
 check_error 'r^100000 vfs_read'		# MAXACT_TOO_BIG
 fi
-- 
cgit v1.3.1


From e2d0d7b2f42dcaf924e9c891c91c9aa22cbbebce Mon Sep 17 00:00:00 2001
From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Date: Tue, 6 Jun 2023 21:39:55 +0900
Subject: tracing/probes: Add tracepoint support on fprobe_events

Allow fprobe_events to trace raw tracepoints so that user can trace
tracepoints which don't have traceevent wrappers. This new event is
always available if the fprobe_events is enabled (thus no kconfig),
because the fprobe_events depends on the trace-event and traceporint.

e.g.
 # echo 't sched_overutilized_tp' >> dynamic_events
 # echo 't 9p_client_req' >> dynamic_events
 # cat dynamic_events
t:tracepoints/sched_overutilized_tp sched_overutilized_tp
t:tracepoints/_9p_client_req 9p_client_req

The event name is based on the tracepoint name, but if it is started
with digit character, an underscore '_' will be added.

NOTE: to avoid further confusion, this renames TPARG_FL_TPOINT to
TPARG_FL_TEVENT because this flag is used for eprobe (trace-event probe).
And reuse TPARG_FL_TPOINT for this raw tracepoint probe.

Link: https://lore.kernel.org/all/168507471874.913472.17214624519622959593.stgit@mhiramat.roam.corp.google.com/

Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202305020453.afTJ3VVp-lkp@intel.com/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 include/linux/tracepoint-defs.h |   1 +
 include/linux/tracepoint.h      |   5 ++
 kernel/trace/trace.c            |   1 +
 kernel/trace/trace_eprobe.c     |   2 +-
 kernel/trace/trace_fprobe.c     | 134 +++++++++++++++++++++++++++++++++++++---
 kernel/trace/trace_probe.c      |  15 +++--
 kernel/trace/trace_probe.h      |  15 ++++-
 7 files changed, 157 insertions(+), 16 deletions(-)

(limited to 'include')

diff --git a/include/linux/tracepoint-defs.h b/include/linux/tracepoint-defs.h
index e7c2276be33e..4dc4955f0fbf 100644
--- a/include/linux/tracepoint-defs.h
+++ b/include/linux/tracepoint-defs.h
@@ -35,6 +35,7 @@ struct tracepoint {
 	struct static_call_key *static_call_key;
 	void *static_call_tramp;
 	void *iterator;
+	void *probestub;
 	int (*regfunc)(void);
 	void (*unregfunc)(void);
 	struct tracepoint_func __rcu *funcs;
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 6811e43c1b5c..88c0ba623ee6 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -303,6 +303,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
 	__section("__tracepoints_strings") = #_name;			\
 	extern struct static_call_key STATIC_CALL_KEY(tp_func_##_name);	\
 	int __traceiter_##_name(void *__data, proto);			\
+	void __probestub_##_name(void *__data, proto);			\
 	struct tracepoint __tracepoint_##_name	__used			\
 	__section("__tracepoints") = {					\
 		.name = __tpstrtab_##_name,				\
@@ -310,6 +311,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
 		.static_call_key = &STATIC_CALL_KEY(tp_func_##_name),	\
 		.static_call_tramp = STATIC_CALL_TRAMP_ADDR(tp_func_##_name), \
 		.iterator = &__traceiter_##_name,			\
+		.probestub = &__probestub_##_name,			\
 		.regfunc = _reg,					\
 		.unregfunc = _unreg,					\
 		.funcs = NULL };					\
@@ -330,6 +332,9 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
 		}							\
 		return 0;						\
 	}								\
+	void __probestub_##_name(void *__data, proto)			\
+	{								\
+	}								\
 	DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name);
 
 #define DEFINE_TRACE(name, proto, args)		\
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 755b0bf2e1ac..fa4e1a18da70 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5681,6 +5681,7 @@ static const char readme_msg[] =
 #endif
 #ifdef CONFIG_FPROBE_EVENTS
 	"\t           f[:[<group>/][<event>]] <func-name>[%return] [<args>]\n"
+	"\t           t[:[<group>/][<event>]] <tracepoint> [<args>]\n"
 #endif
 #ifdef CONFIG_HIST_TRIGGERS
 	"\t           s:[synthetic/]<event> <field> [<field>]\n"
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 67e854979d53..fd64cd5d5745 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -817,7 +817,7 @@ find_and_get_event(const char *system, const char *event_name)
 
 static int trace_eprobe_tp_update_arg(struct trace_eprobe *ep, const char *argv[], int i)
 {
-	unsigned int flags = TPARG_FL_KERNEL | TPARG_FL_TPOINT;
+	unsigned int flags = TPARG_FL_KERNEL | TPARG_FL_TEVENT;
 	int ret;
 
 	ret = traceprobe_parse_probe_arg(&ep->tp, i, argv[i], flags);
diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
index 48dbbc72b7dd..aa71ccb4205c 100644
--- a/kernel/trace/trace_fprobe.c
+++ b/kernel/trace/trace_fprobe.c
@@ -9,6 +9,7 @@
 #include <linux/module.h>
 #include <linux/rculist.h>
 #include <linux/security.h>
+#include <linux/tracepoint.h>
 #include <linux/uaccess.h>
 
 #include "trace_dynevent.h"
@@ -17,6 +18,7 @@
 #include "trace_probe_tmpl.h"
 
 #define FPROBE_EVENT_SYSTEM "fprobes"
+#define TRACEPOINT_EVENT_SYSTEM "tracepoints"
 #define RETHOOK_MAXACTIVE_MAX 4096
 
 static int trace_fprobe_create(const char *raw_command);
@@ -41,6 +43,8 @@ struct trace_fprobe {
 	struct dyn_event	devent;
 	struct fprobe		fp;
 	const char		*symbol;
+	struct tracepoint	*tpoint;
+	struct module		*mod;
 	struct trace_probe	tp;
 };
 
@@ -68,6 +72,11 @@ static bool trace_fprobe_is_return(struct trace_fprobe *tf)
 	return tf->fp.exit_handler != NULL;
 }
 
+static bool trace_fprobe_is_tracepoint(struct trace_fprobe *tf)
+{
+	return tf->tpoint != NULL;
+}
+
 static const char *trace_fprobe_symbol(struct trace_fprobe *tf)
 {
 	return tf->symbol ? tf->symbol : "unknown";
@@ -668,6 +677,21 @@ static int __register_trace_fprobe(struct trace_fprobe *tf)
 	else
 		tf->fp.flags |= FPROBE_FL_DISABLED;
 
+	if (trace_fprobe_is_tracepoint(tf)) {
+		struct tracepoint *tpoint = tf->tpoint;
+		unsigned long ip = (unsigned long)tpoint->probestub;
+		/*
+		 * Here, we do 2 steps to enable fprobe on a tracepoint.
+		 * At first, put __probestub_##TP function on the tracepoint
+		 * and put a fprobe on the stub function.
+		 */
+		ret = tracepoint_probe_register_prio_may_exist(tpoint,
+					tpoint->probestub, NULL, 0);
+		if (ret < 0)
+			return ret;
+		return register_fprobe_ips(&tf->fp, &ip, 1);
+	}
+
 	/* TODO: handle filter, nofilter or symbol list */
 	return register_fprobe(&tf->fp, tf->symbol, NULL);
 }
@@ -678,6 +702,12 @@ static void __unregister_trace_fprobe(struct trace_fprobe *tf)
 	if (trace_fprobe_is_registered(tf)) {
 		unregister_fprobe(&tf->fp);
 		memset(&tf->fp, 0, sizeof(tf->fp));
+		if (trace_fprobe_is_tracepoint(tf)) {
+			tracepoint_probe_unregister(tf->tpoint,
+					tf->tpoint->probestub, NULL);
+			tf->tpoint = NULL;
+			tf->mod = NULL;
+		}
 	}
 }
 
@@ -741,7 +771,8 @@ static int append_trace_fprobe(struct trace_fprobe *tf, struct trace_fprobe *to)
 {
 	int ret;
 
-	if (trace_fprobe_is_return(tf) != trace_fprobe_is_return(to)) {
+	if (trace_fprobe_is_return(tf) != trace_fprobe_is_return(to) ||
+	    trace_fprobe_is_tracepoint(tf) != trace_fprobe_is_tracepoint(to)) {
 		trace_probe_log_set_index(0);
 		trace_probe_log_err(0, DIFF_PROBE_TYPE);
 		return -EEXIST;
@@ -811,6 +842,60 @@ end:
 	return ret;
 }
 
+#ifdef CONFIG_MODULES
+static int __tracepoint_probe_module_cb(struct notifier_block *self,
+					unsigned long val, void *data)
+{
+	struct tp_module *tp_mod = data;
+	struct trace_fprobe *tf;
+	struct dyn_event *pos;
+
+	if (val != MODULE_STATE_GOING)
+		return NOTIFY_DONE;
+
+	mutex_lock(&event_mutex);
+	for_each_trace_fprobe(tf, pos) {
+		if (tp_mod->mod == tf->mod) {
+			tracepoint_probe_unregister(tf->tpoint,
+					tf->tpoint->probestub, NULL);
+			tf->tpoint = NULL;
+			tf->mod = NULL;
+		}
+	}
+	mutex_unlock(&event_mutex);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block tracepoint_module_nb = {
+	.notifier_call = __tracepoint_probe_module_cb,
+};
+#endif /* CONFIG_MODULES */
+
+struct __find_tracepoint_cb_data {
+	const char *tp_name;
+	struct tracepoint *tpoint;
+};
+
+static void __find_tracepoint_cb(struct tracepoint *tp, void *priv)
+{
+	struct __find_tracepoint_cb_data *data = priv;
+
+	if (!data->tpoint && !strcmp(data->tp_name, tp->name))
+		data->tpoint = tp;
+}
+
+static struct tracepoint *find_tracepoint(const char *tp_name)
+{
+	struct __find_tracepoint_cb_data data = {
+		.tp_name = tp_name,
+	};
+
+	for_each_kernel_tracepoint(__find_tracepoint_cb, &data);
+
+	return data.tpoint;
+}
+
 static int __trace_fprobe_create(int argc, const char *argv[])
 {
 	/*
@@ -819,6 +904,8 @@ static int __trace_fprobe_create(int argc, const char *argv[])
 	 *      f[:[GRP/][EVENT]] [MOD:]KSYM [FETCHARGS]
 	 *  - Add fexit probe:
 	 *      f[N][:[GRP/][EVENT]] [MOD:]KSYM%return [FETCHARGS]
+	 *  - Add tracepoint probe:
+	 *      t[:[GRP/][EVENT]] TRACEPOINT [FETCHARGS]
 	 *
 	 * Fetch args:
 	 *  $retval	: fetch return value
@@ -844,10 +931,16 @@ static int __trace_fprobe_create(int argc, const char *argv[])
 	char buf[MAX_EVENT_NAME_LEN];
 	char gbuf[MAX_EVENT_NAME_LEN];
 	unsigned int flags = TPARG_FL_KERNEL | TPARG_FL_FPROBE;
+	bool is_tracepoint = false;
 
-	if (argv[0][0] != 'f' || argc < 2)
+	if ((argv[0][0] != 'f' && argv[0][0] != 't') || argc < 2)
 		return -ECANCELED;
 
+	if (argv[0][0] == 't') {
+		is_tracepoint = true;
+		group = TRACEPOINT_EVENT_SYSTEM;
+	}
+
 	trace_probe_log_init("trace_fprobe", argc, argv);
 
 	event = strchr(&argv[0][1], ':');
@@ -881,14 +974,14 @@ static int __trace_fprobe_create(int argc, const char *argv[])
 
 	trace_probe_log_set_index(1);
 
-	/* a symbol specified */
+	/* a symbol(or tracepoint) must be specified */
 	symbol = kstrdup(argv[1], GFP_KERNEL);
 	if (!symbol)
 		return -ENOMEM;
 
 	tmp = strchr(symbol, '%');
 	if (tmp) {
-		if (!strcmp(tmp, "%return")) {
+		if (!is_tracepoint && !strcmp(tmp, "%return")) {
 			*tmp = '\0';
 			is_return = true;
 		} else {
@@ -907,6 +1000,9 @@ static int __trace_fprobe_create(int argc, const char *argv[])
 	else
 		flags |= TPARG_FL_FENTRY;
 
+	if (is_tracepoint)
+		flags |= TPARG_FL_TPOINT;
+
 	trace_probe_log_set_index(0);
 	if (event) {
 		ret = traceprobe_parse_event_name(&event, &group, gbuf,
@@ -917,8 +1013,11 @@ static int __trace_fprobe_create(int argc, const char *argv[])
 
 	if (!event) {
 		/* Make a new event name */
-		snprintf(buf, MAX_EVENT_NAME_LEN, "%s__%s", symbol,
-			 is_return ? "exit" : "entry");
+		if (is_tracepoint)
+			strscpy(buf, symbol, MAX_EVENT_NAME_LEN);
+		else
+			snprintf(buf, MAX_EVENT_NAME_LEN, "%s__%s", symbol,
+				 is_return ? "exit" : "entry");
 		sanitize_event_name(buf);
 		event = buf;
 	}
@@ -932,6 +1031,18 @@ static int __trace_fprobe_create(int argc, const char *argv[])
 		WARN_ON_ONCE(ret != -ENOMEM);
 		goto out;	/* We know tf is not allocated */
 	}
+
+	if (is_tracepoint) {
+		tf->tpoint = find_tracepoint(tf->symbol);
+		if (!tf->tpoint) {
+			trace_probe_log_set_index(1);
+			trace_probe_log_err(0, NO_TRACEPOINT);
+			goto parse_error;
+		}
+		tf->mod = __module_text_address(
+				(unsigned long)tf->tpoint->probestub);
+	}
+
 	argc -= 2; argv += 2;
 
 	/* parse arguments */
@@ -991,7 +1102,10 @@ static int trace_fprobe_show(struct seq_file *m, struct dyn_event *ev)
 	struct trace_fprobe *tf = to_trace_fprobe(ev);
 	int i;
 
-	seq_putc(m, 'f');
+	if (trace_fprobe_is_tracepoint(tf))
+		seq_putc(m, 't');
+	else
+		seq_putc(m, 'f');
 	if (trace_fprobe_is_return(tf) && tf->fp.nr_maxactive)
 		seq_printf(m, "%d", tf->fp.nr_maxactive);
 	seq_printf(m, ":%s/%s", trace_probe_group_name(&tf->tp),
@@ -1048,6 +1162,12 @@ static __init int init_fprobe_trace_early(void)
 	if (ret)
 		return ret;
 
+#ifdef CONFIG_MODULES
+	ret = register_tracepoint_module_notifier(&tracepoint_module_nb);
+	if (ret)
+		return ret;
+#endif
+
 	return 0;
 }
 core_initcall(init_fprobe_trace_early);
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index c39860fb2e41..798f18d24ebc 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -292,7 +292,7 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,
 	int ret = 0;
 	int len;
 
-	if (flags & TPARG_FL_TPOINT) {
+	if (flags & TPARG_FL_TEVENT) {
 		if (code->data)
 			return -EFAULT;
 		code->data = kstrdup(arg, GFP_KERNEL);
@@ -326,8 +326,7 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,
 	} else if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
 		code->op = FETCH_OP_COMM;
 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
-	} else if (((flags & TPARG_FL_MASK) ==
-		    (TPARG_FL_KERNEL | TPARG_FL_FENTRY)) &&
+	} else if (tparg_is_function_entry(flags) &&
 		   (len = str_has_prefix(arg, "arg"))) {
 		ret = kstrtoul(arg + len, 10, &param);
 		if (ret) {
@@ -338,6 +337,12 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,
 		}
 		code->op = FETCH_OP_ARG;
 		code->param = (unsigned int)param - 1;
+		/*
+		 * The tracepoint probe will probe a stub function, and the
+		 * first parameter of the stub is a dummy and should be ignored.
+		 */
+		if (flags & TPARG_FL_TPOINT)
+			code->param++;
 #endif
 	} else
 		goto inval_var;
@@ -393,7 +398,7 @@ parse_probe_arg(char *arg, const struct fetch_type *type,
 		break;
 
 	case '%':	/* named register */
-		if (flags & (TPARG_FL_TPOINT | TPARG_FL_FPROBE)) {
+		if (flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) {
 			/* eprobe and fprobe do not handle registers */
 			trace_probe_log_err(offs, BAD_VAR);
 			break;
@@ -633,7 +638,7 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
 	 * Since $comm and immediate string can not be dereferenced,
 	 * we can find those by strcmp. But ignore for eprobes.
 	 */
-	if (!(flags & TPARG_FL_TPOINT) &&
+	if (!(flags & TPARG_FL_TEVENT) &&
 	    (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
 	     strncmp(arg, "\\\"", 2) == 0)) {
 		/* The type of $comm must be "string", and not an array. */
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 8f4f23e8b234..e6b94fcdb886 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -359,16 +359,24 @@ int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_a
 
 /*
  * The flags used for parsing trace_probe arguments.
- * TPARG_FL_RETURN, TPARG_FL_FENTRY and TPARG_FL_TPOINT are mutually exclusive.
+ * TPARG_FL_RETURN, TPARG_FL_FENTRY and TPARG_FL_TEVENT are mutually exclusive.
  * TPARG_FL_KERNEL and TPARG_FL_USER are also mutually exclusive.
+ * TPARG_FL_FPROBE and TPARG_FL_TPOINT are optional but it should be with
+ * TPARG_FL_KERNEL.
  */
 #define TPARG_FL_RETURN BIT(0)
 #define TPARG_FL_KERNEL BIT(1)
 #define TPARG_FL_FENTRY BIT(2)
-#define TPARG_FL_TPOINT BIT(3)
+#define TPARG_FL_TEVENT BIT(3)
 #define TPARG_FL_USER   BIT(4)
 #define TPARG_FL_FPROBE BIT(5)
-#define TPARG_FL_MASK	GENMASK(4, 0)
+#define TPARG_FL_TPOINT BIT(6)
+#define TPARG_FL_LOC_MASK	GENMASK(4, 0)
+
+static inline bool tparg_is_function_entry(unsigned int flags)
+{
+	return (flags & TPARG_FL_LOC_MASK) == (TPARG_FL_KERNEL | TPARG_FL_FENTRY);
+}
 
 extern int traceprobe_parse_probe_arg(struct trace_probe *tp, int i,
 				const char *argv, unsigned int flags);
@@ -415,6 +423,7 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 	C(MAXACT_TOO_BIG,	"Maxactive is too big"),		\
 	C(BAD_PROBE_ADDR,	"Invalid probed address or symbol"),	\
 	C(BAD_RETPROBE,		"Retprobe address must be an function entry"), \
+	C(NO_TRACEPOINT,	"Tracepoint is not found"),		\
 	C(BAD_ADDR_SUFFIX,	"Invalid probed address suffix"), \
 	C(NO_GROUP_NAME,	"Group name is not specified"),		\
 	C(GROUP_TOO_LONG,	"Group name is too long"),		\
-- 
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