Merge commit 'origin/master' into next

Conflicts:
	include/linux/kvm.h

1 files changed, 1523 insertions, 0 deletions

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
new file mode 100644
index 00000000000..aff5f80b59b
--- /dev/null
+++ b/kernel/trace/trace_kprobe.c
@@ -0,0 +1,1523 @@
+/*
+ * Kprobes-based tracing events
+ *
+ * Created by Masami Hiramatsu <mhiramat@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <linux/kprobes.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/smp.h>
+#include <linux/debugfs.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/ptrace.h>
+#include <linux/perf_event.h>
+
+#include "trace.h"
+#include "trace_output.h"
+
+#define MAX_TRACE_ARGS 128
+#define MAX_ARGSTR_LEN 63
+#define MAX_EVENT_NAME_LEN 64
+#define KPROBE_EVENT_SYSTEM "kprobes"
+
+/* Reserved field names */
+#define FIELD_STRING_IP "__probe_ip"
+#define FIELD_STRING_NARGS "__probe_nargs"
+#define FIELD_STRING_RETIP "__probe_ret_ip"
+#define FIELD_STRING_FUNC "__probe_func"
+
+const char *reserved_field_names[] = {
+	"common_type",
+	"common_flags",
+	"common_preempt_count",
+	"common_pid",
+	"common_tgid",
+	"common_lock_depth",
+	FIELD_STRING_IP,
+	FIELD_STRING_NARGS,
+	FIELD_STRING_RETIP,
+	FIELD_STRING_FUNC,
+};
+
+struct fetch_func {
+	unsigned long (*func)(struct pt_regs *, void *);
+	void *data;
+};
+
+static __kprobes unsigned long call_fetch(struct fetch_func *f,
+					  struct pt_regs *regs)
+{
+	return f->func(regs, f->data);
+}
+
+/* fetch handlers */
+static __kprobes unsigned long fetch_register(struct pt_regs *regs,
+					      void *offset)
+{
+	return regs_get_register(regs, (unsigned int)((unsigned long)offset));
+}
+
+static __kprobes unsigned long fetch_stack(struct pt_regs *regs,
+					   void *num)
+{
+	return regs_get_kernel_stack_nth(regs,
+					 (unsigned int)((unsigned long)num));
+}
+
+static __kprobes unsigned long fetch_memory(struct pt_regs *regs, void *addr)
+{
+	unsigned long retval;
+
+	if (probe_kernel_address(addr, retval))
+		return 0;
+	return retval;
+}
+
+static __kprobes unsigned long fetch_argument(struct pt_regs *regs, void *num)
+{
+	return regs_get_argument_nth(regs, (unsigned int)((unsigned long)num));
+}
+
+static __kprobes unsigned long fetch_retvalue(struct pt_regs *regs,
+					      void *dummy)
+{
+	return regs_return_value(regs);
+}
+
+static __kprobes unsigned long fetch_stack_address(struct pt_regs *regs,
+						   void *dummy)
+{
+	return kernel_stack_pointer(regs);
+}
+
+/* Memory fetching by symbol */
+struct symbol_cache {
+	char *symbol;
+	long offset;
+	unsigned long addr;
+};
+
+static unsigned long update_symbol_cache(struct symbol_cache *sc)
+{
+	sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
+	if (sc->addr)
+		sc->addr += sc->offset;
+	return sc->addr;
+}
+
+static void free_symbol_cache(struct symbol_cache *sc)
+{
+	kfree(sc->symbol);
+	kfree(sc);
+}
+
+static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
+{
+	struct symbol_cache *sc;
+
+	if (!sym || strlen(sym) == 0)
+		return NULL;
+	sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
+	if (!sc)
+		return NULL;
+
+	sc->symbol = kstrdup(sym, GFP_KERNEL);
+	if (!sc->symbol) {
+		kfree(sc);
+		return NULL;
+	}
+	sc->offset = offset;
+
+	update_symbol_cache(sc);
+	return sc;
+}
+
+static __kprobes unsigned long fetch_symbol(struct pt_regs *regs, void *data)
+{
+	struct symbol_cache *sc = data;
+
+	if (sc->addr)
+		return fetch_memory(regs, (void *)sc->addr);
+	else
+		return 0;
+}
+
+/* Special indirect memory access interface */
+struct indirect_fetch_data {
+	struct fetch_func orig;
+	long offset;
+};
+
+static __kprobes unsigned long fetch_indirect(struct pt_regs *regs, void *data)
+{
+	struct indirect_fetch_data *ind = data;
+	unsigned long addr;
+
+	addr = call_fetch(&ind->orig, regs);
+	if (addr) {
+		addr += ind->offset;
+		return fetch_memory(regs, (void *)addr);
+	} else
+		return 0;
+}
+
+static __kprobes void free_indirect_fetch_data(struct indirect_fetch_data *data)
+{
+	if (data->orig.func == fetch_indirect)
+		free_indirect_fetch_data(data->orig.data);
+	else if (data->orig.func == fetch_symbol)
+		free_symbol_cache(data->orig.data);
+	kfree(data);
+}
+
+/**
+ * Kprobe event core functions
+ */
+
+struct probe_arg {
+	struct fetch_func	fetch;
+	const char		*name;
+};
+
+/* Flags for trace_probe */
+#define TP_FLAG_TRACE	1
+#define TP_FLAG_PROFILE	2
+
+struct trace_probe {
+	struct list_head	list;
+	struct kretprobe	rp;	/* Use rp.kp for kprobe use */
+	unsigned long 		nhit;
+	unsigned int		flags;	/* For TP_FLAG_* */
+	const char		*symbol;	/* symbol name */
+	struct ftrace_event_call	call;
+	struct trace_event		event;
+	unsigned int		nr_args;
+	struct probe_arg	args[];
+};
+
+#define SIZEOF_TRACE_PROBE(n)			\
+	(offsetof(struct trace_probe, args) +	\
+	(sizeof(struct probe_arg) * (n)))
+
+static __kprobes int probe_is_return(struct trace_probe *tp)
+{
+	return tp->rp.handler != NULL;
+}
+
+static __kprobes const char *probe_symbol(struct trace_probe *tp)
+{
+	return tp->symbol ? tp->symbol : "unknown";
+}
+
+static int probe_arg_string(char *buf, size_t n, struct fetch_func *ff)
+{
+	int ret = -EINVAL;
+
+	if (ff->func == fetch_argument)
+		ret = snprintf(buf, n, "$arg%lu", (unsigned long)ff->data);
+	else if (ff->func == fetch_register) {
+		const char *name;
+		name = regs_query_register_name((unsigned int)((long)ff->data));
+		ret = snprintf(buf, n, "%%%s", name);
+	} else if (ff->func == fetch_stack)
+		ret = snprintf(buf, n, "$stack%lu", (unsigned long)ff->data);
+	else if (ff->func == fetch_memory)
+		ret = snprintf(buf, n, "@0x%p", ff->data);
+	else if (ff->func == fetch_symbol) {
+		struct symbol_cache *sc = ff->data;
+		if (sc->offset)
+			ret = snprintf(buf, n, "@%s%+ld", sc->symbol,
+					sc->offset);
+		else
+			ret = snprintf(buf, n, "@%s", sc->symbol);
+	} else if (ff->func == fetch_retvalue)
+		ret = snprintf(buf, n, "$retval");
+	else if (ff->func == fetch_stack_address)
+		ret = snprintf(buf, n, "$stack");
+	else if (ff->func == fetch_indirect) {
+		struct indirect_fetch_data *id = ff->data;
+		size_t l = 0;
+		ret = snprintf(buf, n, "%+ld(", id->offset);
+		if (ret >= n)
+			goto end;
+		l += ret;
+		ret = probe_arg_string(buf + l, n - l, &id->orig);
+		if (ret < 0)
+			goto end;
+		l += ret;
+		ret = snprintf(buf + l, n - l, ")");
+		ret += l;
+	}
+end:
+	if (ret >= n)
+		return -ENOSPC;
+	return ret;
+}
+
+static int register_probe_event(struct trace_probe *tp);
+static void unregister_probe_event(struct trace_probe *tp);
+
+static DEFINE_MUTEX(probe_lock);
+static LIST_HEAD(probe_list);
+
+static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
+static int kretprobe_dispatcher(struct kretprobe_instance *ri,
+				struct pt_regs *regs);
+
+/*
+ * Allocate new trace_probe and initialize it (including kprobes).
+ */
+static struct trace_probe *alloc_trace_probe(const char *group,
+					     const char *event,
+					     void *addr,
+					     const char *symbol,
+					     unsigned long offs,
+					     int nargs, int is_return)
+{
+	struct trace_probe *tp;
+
+	tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
+	if (!tp)
+		return ERR_PTR(-ENOMEM);
+
+	if (symbol) {
+		tp->symbol = kstrdup(symbol, GFP_KERNEL);
+		if (!tp->symbol)
+			goto error;
+		tp->rp.kp.symbol_name = tp->symbol;
+		tp->rp.kp.offset = offs;
+	} else
+		tp->rp.kp.addr = addr;
+
+	if (is_return)
+		tp->rp.handler = kretprobe_dispatcher;
+	else
+		tp->rp.kp.pre_handler = kprobe_dispatcher;
+
+	if (!event)
+		goto error;
+	tp->call.name = kstrdup(event, GFP_KERNEL);
+	if (!tp->call.name)
+		goto error;
+
+	if (!group)
+		goto error;
+	tp->call.system = kstrdup(group, GFP_KERNEL);
+	if (!tp->call.system)
+		goto error;
+
+	INIT_LIST_HEAD(&tp->list);
+	return tp;
+error:
+	kfree(tp->call.name);
+	kfree(tp->symbol);
+	kfree(tp);
+	return ERR_PTR(-ENOMEM);
+}
+
+static void free_probe_arg(struct probe_arg *arg)
+{
+	if (arg->fetch.func == fetch_symbol)
+		free_symbol_cache(arg->fetch.data);
+	else if (arg->fetch.func == fetch_indirect)
+		free_indirect_fetch_data(arg->fetch.data);
+	kfree(arg->name);
+}
+
+static void free_trace_probe(struct trace_probe *tp)
+{
+	int i;
+
+	for (i = 0; i < tp->nr_args; i++)
+		free_probe_arg(&tp->args[i]);
+
+	kfree(tp->call.system);
+	kfree(tp->call.name);
+	kfree(tp->symbol);
+	kfree(tp);
+}
+
+static struct trace_probe *find_probe_event(const char *event,
+					    const char *group)
+{
+	struct trace_probe *tp;
+
+	list_for_each_entry(tp, &probe_list, list)
+		if (strcmp(tp->call.name, event) == 0 &&
+		    strcmp(tp->call.system, group) == 0)
+			return tp;
+	return NULL;
+}
+
+/* Unregister a trace_probe and probe_event: call with locking probe_lock */
+static void unregister_trace_probe(struct trace_probe *tp)
+{
+	if (probe_is_return(tp))
+		unregister_kretprobe(&tp->rp);
+	else
+		unregister_kprobe(&tp->rp.kp);
+	list_del(&tp->list);
+	unregister_probe_event(tp);
+}
+
+/* Register a trace_probe and probe_event */
+static int register_trace_probe(struct trace_probe *tp)
+{
+	struct trace_probe *old_tp;
+	int ret;
+
+	mutex_lock(&probe_lock);
+
+	/* register as an event */
+	old_tp = find_probe_event(tp->call.name, tp->call.system);
+	if (old_tp) {
+		/* delete old event */
+		unregister_trace_probe(old_tp);
+		free_trace_probe(old_tp);
+	}
+	ret = register_probe_event(tp);
+	if (ret) {
+		pr_warning("Faild to register probe event(%d)\n", ret);
+		goto end;
+	}
+
+	tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
+	if (probe_is_return(tp))
+		ret = register_kretprobe(&tp->rp);
+	else
+		ret = register_kprobe(&tp->rp.kp);
+
+	if (ret) {
+		pr_warning("Could not insert probe(%d)\n", ret);
+		if (ret == -EILSEQ) {
+			pr_warning("Probing address(0x%p) is not an "
+				   "instruction boundary.\n",
+				   tp->rp.kp.addr);
+			ret = -EINVAL;
+		}
+		unregister_probe_event(tp);
+	} else
+		list_add_tail(&tp->list, &probe_list);
+end:
+	mutex_unlock(&probe_lock);
+	return ret;
+}
+
+/* Split symbol and offset. */
+static int split_symbol_offset(char *symbol, unsigned long *offset)
+{
+	char *tmp;
+	int ret;
+
+	if (!offset)
+		return -EINVAL;
+
+	tmp = strchr(symbol, '+');
+	if (tmp) {
+		/* skip sign because strict_strtol doesn't accept '+' */
+		ret = strict_strtoul(tmp + 1, 0, offset);
+		if (ret)
+			return ret;
+		*tmp = '\0';
+	} else
+		*offset = 0;
+	return 0;
+}
+
+#define PARAM_MAX_ARGS 16
+#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
+
+static int parse_probe_vars(char *arg, struct fetch_func *ff, int is_return)
+{
+	int ret = 0;
+	unsigned long param;
+
+	if (strcmp(arg, "retval") == 0) {
+		if (is_return) {
+			ff->func = fetch_retvalue;
+			ff->data = NULL;
+		} else
+			ret = -EINVAL;
+	} else if (strncmp(arg, "stack", 5) == 0) {
+		if (arg[5] == '\0') {
+			ff->func = fetch_stack_address;
+			ff->data = NULL;
+		} else if (isdigit(arg[5])) {
+			ret = strict_strtoul(arg + 5, 10, &param);
+			if (ret || param > PARAM_MAX_STACK)
+				ret = -EINVAL;
+			else {
+				ff->func = fetch_stack;
+				ff->data = (void *)param;
+			}
+		} else
+			ret = -EINVAL;
+	} else if (strncmp(arg, "arg", 3) == 0 && isdigit(arg[3])) {
+		ret = strict_strtoul(arg + 3, 10, &param);
+		if (ret || param > PARAM_MAX_ARGS)
+			ret = -EINVAL;
+		else {
+			ff->func = fetch_argument;
+			ff->data = (void *)param;
+		}
+	} else
+		ret = -EINVAL;
+	return ret;
+}
+
+/* Recursive argument parser */
+static int __parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
+{
+	int ret = 0;
+	unsigned long param;
+	long offset;
+	char *tmp;
+
+	switch (arg[0]) {
+	case '$':
+		ret = parse_probe_vars(arg + 1, ff, is_return);
+		break;
+	case '%':	/* named register */
+		ret = regs_query_register_offset(arg + 1);
+		if (ret >= 0) {
+			ff->func = fetch_register;
+			ff->data = (void *)(unsigned long)ret;
+			ret = 0;
+		}
+		break;
+	case '@':	/* memory or symbol */
+		if (isdigit(arg[1])) {
+			ret = strict_strtoul(arg + 1, 0, &param);
+			if (ret)
+				break;
+			ff->func = fetch_memory;
+			ff->data = (void *)param;
+		} else {
+			ret = split_symbol_offset(arg + 1, &offset);
+			if (ret)
+				break;
+			ff->data = alloc_symbol_cache(arg + 1, offset);
+			if (ff->data)
+				ff->func = fetch_symbol;
+			else
+				ret = -EINVAL;
+		}
+		break;
+	case '+':	/* indirect memory */
+	case '-':
+		tmp = strchr(arg, '(');
+		if (!tmp) {
+			ret = -EINVAL;
+			break;
+		}
+		*tmp = '\0';
+		ret = strict_strtol(arg + 1, 0, &offset);
+		if (ret)
+			break;
+		if (arg[0] == '-')
+			offset = -offset;
+		arg = tmp + 1;
+		tmp = strrchr(arg, ')');
+		if (tmp) {
+			struct indirect_fetch_data *id;
+			*tmp = '\0';
+			id = kzalloc(sizeof(struct indirect_fetch_data),
+				     GFP_KERNEL);
+			if (!id)
+				return -ENOMEM;
+			id->offset = offset;
+			ret = __parse_probe_arg(arg, &id->orig, is_return);
+			if (ret)
+				kfree(id);
+			else {
+				ff->func = fetch_indirect;
+				ff->data = (void *)id;
+			}
+		} else
+			ret = -EINVAL;
+		break;
+	default:
+		/* TODO: support custom handler */
+		ret = -EINVAL;
+	}
+	return ret;
+}
+
+/* String length checking wrapper */
+static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
+{
+	if (strlen(arg) > MAX_ARGSTR_LEN) {
+		pr_info("Argument is too long.: %s\n",  arg);
+		return -ENOSPC;
+	}
+	return __parse_probe_arg(arg, ff, is_return);
+}
+
+/* Return 1 if name is reserved or already used by another argument */
+static int conflict_field_name(const char *name,
+			       struct probe_arg *args, int narg)
+{
+	int i;
+	for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
+		if (strcmp(reserved_field_names[i], name) == 0)
+			return 1;
+	for (i = 0; i < narg; i++)
+		if (strcmp(args[i].name, name) == 0)
+			return 1;
+	return 0;
+}
+
+static int create_trace_probe(int argc, char **argv)
+{
+	/*
+	 * Argument syntax:
+	 *  - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS]
+	 *  - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS]
+	 * Fetch args:
+	 *  $argN	: fetch Nth of function argument. (N:0-)
+	 *  $retval	: fetch return value
+	 *  $stack	: fetch stack address
+	 *  $stackN	: fetch Nth of stack (N:0-)
+	 *  @ADDR	: fetch memory at ADDR (ADDR should be in kernel)
+	 *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
+	 *  %REG	: fetch register REG
+	 * Indirect memory fetch:
+	 *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
+	 * Alias name of args:
+	 *  NAME=FETCHARG : set NAME as alias of FETCHARG.
+	 */
+	struct trace_probe *tp;
+	int i, ret = 0;
+	int is_return = 0;
+	char *symbol = NULL, *event = NULL, *arg = NULL, *group = NULL;
+	unsigned long offset = 0;
+	void *addr = NULL;
+	char buf[MAX_EVENT_NAME_LEN];
+
+	if (argc < 2) {
+		pr_info("Probe point is not specified.\n");
+		return -EINVAL;
+	}
+
+	if (argv[0][0] == 'p')
+		is_return = 0;
+	else if (argv[0][0] == 'r')
+		is_return = 1;
+	else {
+		pr_info("Probe definition must be started with 'p' or 'r'.\n");
+		return -EINVAL;
+	}
+
+	if (argv[0][1] == ':') {
+		event = &argv[0][2];
+		if (strchr(event, '/')) {
+			group = event;
+			event = strchr(group, '/') + 1;
+			event[-1] = '\0';
+			if (strlen(group) == 0) {
+				pr_info("Group name is not specifiled\n");
+				return -EINVAL;
+			}
+		}
+		if (strlen(event) == 0) {
+			pr_info("Event name is not specifiled\n");
+			return -EINVAL;
+		}
+	}
+
+	if (isdigit(argv[1][0])) {
+		if (is_return) {
+			pr_info("Return probe point must be a symbol.\n");
+			return -EINVAL;
+		}
+		/* an address specified */
+		ret = strict_strtoul(&argv[0][2], 0, (unsigned long *)&addr);
+		if (ret) {
+			pr_info("Failed to parse address.\n");
+			return ret;
+		}
+	} else {
+		/* a symbol specified */
+		symbol = argv[1];
+		/* TODO: support .init module functions */
+		ret = split_symbol_offset(symbol, &offset);
+		if (ret) {
+			pr_info("Failed to parse symbol.\n");
+			return ret;
+		}
+		if (offset && is_return) {
+			pr_info("Return probe must be used without offset.\n");
+			return -EINVAL;
+		}
+	}
+	argc -= 2; argv += 2;
+
+	/* setup a probe */
+	if (!group)
+		group = KPROBE_EVENT_SYSTEM;
+	if (!event) {
+		/* Make a new event name */
+		if (symbol)
+			snprintf(buf, MAX_EVENT_NAME_LEN, "%c@%s%+ld",
+				 is_return ? 'r' : 'p', symbol, offset);
+		else
+			snprintf(buf, MAX_EVENT_NAME_LEN, "%c@0x%p",
+				 is_return ? 'r' : 'p', addr);
+		event = buf;
+	}
+	tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
+			       is_return);
+	if (IS_ERR(tp)) {
+		pr_info("Failed to allocate trace_probe.(%d)\n",
+			(int)PTR_ERR(tp));
+		return PTR_ERR(tp);
+	}
+
+	/* parse arguments */
+	ret = 0;
+	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
+		/* Parse argument name */
+		arg = strchr(argv[i], '=');
+		if (arg)
+			*arg++ = '\0';
+		else
+			arg = argv[i];
+
+		if (conflict_field_name(argv[i], tp->args, i)) {
+			pr_info("Argument%d name '%s' conflicts with "
+				"another field.\n", i, argv[i]);
+			ret = -EINVAL;
+			goto error;
+		}
+
+		tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
+		if (!tp->args[i].name) {
+			pr_info("Failed to allocate argument%d name '%s'.\n",
+				i, argv[i]);
+			ret = -ENOMEM;
+			goto error;
+		}
+
+		/* Parse fetch argument */
+		ret = parse_probe_arg(arg, &tp->args[i].fetch, is_return);
+		if (ret) {
+			pr_info("Parse error at argument%d. (%d)\n", i, ret);
+			kfree(tp->args[i].name);
+			goto error;
+		}
+
+		tp->nr_args++;
+	}
+
+	ret = register_trace_probe(tp);
+	if (ret)
+		goto error;
+	return 0;
+
+error:
+	free_trace_probe(tp);
+	return ret;
+}
+
+static void cleanup_all_probes(void)
+{
+	struct trace_probe *tp;
+
+	mutex_lock(&probe_lock);
+	/* TODO: Use batch unregistration */
+	while (!list_empty(&probe_list)) {
+		tp = list_entry(probe_list.next, struct trace_probe, list);
+		unregister_trace_probe(tp);
+		free_trace_probe(tp);
+	}
+	mutex_unlock(&probe_lock);
+}
+
+
+/* Probes listing interfaces */
+static void *probes_seq_start(struct seq_file *m, loff_t *pos)
+{
+	mutex_lock(&probe_lock);
+	return seq_list_start(&probe_list, *pos);
+}
+
+static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	return seq_list_next(v, &probe_list, pos);
+}
+
+static void probes_seq_stop(struct seq_file *m, void *v)
+{
+	mutex_unlock(&probe_lock);
+}
+
+static int probes_seq_show(struct seq_file *m, void *v)
+{
+	struct trace_probe *tp = v;
+	int i, ret;
+	char buf[MAX_ARGSTR_LEN + 1];
+
+	seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p');
+	seq_printf(m, ":%s/%s", tp->call.system, tp->call.name);
+
+	if (!tp->symbol)
+		seq_printf(m, " 0x%p", tp->rp.kp.addr);
+	else if (tp->rp.kp.offset)
+		seq_printf(m, " %s+%u", probe_symbol(tp), tp->rp.kp.offset);
+	else
+		seq_printf(m, " %s", probe_symbol(tp));
+
+	for (i = 0; i < tp->nr_args; i++) {
+		ret = probe_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i].fetch);
+		if (ret < 0) {
+			pr_warning("Argument%d decoding error(%d).\n", i, ret);
+			return ret;
+		}
+		seq_printf(m, " %s=%s", tp->args[i].name, buf);
+	}
+	seq_printf(m, "\n");
+	return 0;
+}
+
+static const struct seq_operations probes_seq_op = {
+	.start  = probes_seq_start,
+	.next   = probes_seq_next,
+	.stop   = probes_seq_stop,
+	.show   = probes_seq_show
+};
+
+static int probes_open(struct inode *inode, struct file *file)
+{
+	if ((file->f_mode & FMODE_WRITE) &&
+	    (file->f_flags & O_TRUNC))
+		cleanup_all_probes();
+
+	return seq_open(file, &probes_seq_op);
+}
+
+static int command_trace_probe(const char *buf)
+{
+	char **argv;
+	int argc = 0, ret = 0;
+
+	argv = argv_split(GFP_KERNEL, buf, &argc);
+	if (!argv)
+		return -ENOMEM;
+
+	if (argc)
+		ret = create_trace_probe(argc, argv);
+
+	argv_free(argv);
+	return ret;
+}
+
+#define WRITE_BUFSIZE 128
+
+static ssize_t probes_write(struct file *file, const char __user *buffer,
+			    size_t count, loff_t *ppos)
+{
+	char *kbuf, *tmp;
+	int ret;
+	size_t done;
+	size_t size;
+
+	kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
+	if (!kbuf)
+		return -ENOMEM;
+
+	ret = done = 0;
+	while (done < count) {
+		size = count - done;
+		if (size >= WRITE_BUFSIZE)
+			size = WRITE_BUFSIZE - 1;
+		if (copy_from_user(kbuf, buffer + done, size)) {
+			ret = -EFAULT;
+			goto out;
+		}
+		kbuf[size] = '\0';
+		tmp = strchr(kbuf, '\n');
+		if (tmp) {
+			*tmp = '\0';
+			size = tmp - kbuf + 1;
+		} else if (done + size < count) {
+			pr_warning("Line length is too long: "
+				   "Should be less than %d.", WRITE_BUFSIZE);
+			ret = -EINVAL;
+			goto out;
+		}
+		done += size;
+		/* Remove comments */
+		tmp = strchr(kbuf, '#');
+		if (tmp)
+			*tmp = '\0';
+
+		ret = command_trace_probe(kbuf);
+		if (ret)
+			goto out;
+	}
+	ret = done;
+out:
+	kfree(kbuf);
+	return ret;
+}
+
+static const struct file_operations kprobe_events_ops = {
+	.owner          = THIS_MODULE,
+	.open           = probes_open,
+	.read           = seq_read,
+	.llseek         = seq_lseek,
+	.release        = seq_release,
+	.write		= probes_write,
+};
+
+/* Probes profiling interfaces */
+static int probes_profile_seq_show(struct seq_file *m, void *v)
+{
+	struct trace_probe *tp = v;
+
+	seq_printf(m, "  %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
+		   tp->rp.kp.nmissed);
+
+	return 0;
+}
+
+static const struct seq_operations profile_seq_op = {
+	.start  = probes_seq_start,
+	.next   = probes_seq_next,
+	.stop   = probes_seq_stop,
+	.show   = probes_profile_seq_show
+};
+
+static int profile_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &profile_seq_op);
+}
+
+static const struct file_operations kprobe_profile_ops = {
+	.owner          = THIS_MODULE,
+	.open           = profile_open,
+	.read           = seq_read,
+	.llseek         = seq_lseek,
+	.release        = seq_release,
+};
+
+/* Kprobe handler */
+static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
+{
+	struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
+	struct kprobe_trace_entry *entry;
+	struct ring_buffer_event *event;
+	struct ring_buffer *buffer;
+	int size, i, pc;
+	unsigned long irq_flags;
+	struct ftrace_event_call *call = &tp->call;
+
+	tp->nhit++;
+
+	local_save_flags(irq_flags);
+	pc = preempt_count();
+
+	size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
+
+	event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
+						  irq_flags, pc);
+	if (!event)
+		return 0;
+
+	entry = ring_buffer_event_data(event);
+	entry->nargs = tp->nr_args;
+	entry->ip = (unsigned long)kp->addr;
+	for (i = 0; i < tp->nr_args; i++)
+		entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
+
+	if (!filter_current_check_discard(buffer, call, entry, event))
+		trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
+	return 0;
+}
+
+/* Kretprobe handler */
+static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri,
+					  struct pt_regs *regs)
+{
+	struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
+	struct kretprobe_trace_entry *entry;
+	struct ring_buffer_event *event;
+	struct ring_buffer *buffer;
+	int size, i, pc;
+	unsigned long irq_flags;
+	struct ftrace_event_call *call = &tp->call;
+
+	local_save_flags(irq_flags);
+	pc = preempt_count();
+
+	size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
+
+	event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
+						  irq_flags, pc);
+	if (!event)
+		return 0;
+
+	entry = ring_buffer_event_data(event);
+	entry->nargs = tp->nr_args;
+	entry->func = (unsigned long)tp->rp.kp.addr;
+	entry->ret_ip = (unsigned long)ri->ret_addr;
+	for (i = 0; i < tp->nr_args; i++)
+		entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
+
+	if (!filter_current_check_discard(buffer, call, entry, event))
+		trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
+
+	return 0;
+}
+
+/* Event entry printers */
+enum print_line_t
+print_kprobe_event(struct trace_iterator *iter, int flags)
+{
+	struct kprobe_trace_entry *field;
+	struct trace_seq *s = &iter->seq;
+	struct trace_event *event;
+	struct trace_probe *tp;
+	int i;
+
+	field = (struct kprobe_trace_entry *)iter->ent;
+	event = ftrace_find_event(field->ent.type);
+	tp = container_of(event, struct trace_probe, event);
+
+	if (!trace_seq_printf(s, "%s: (", tp->call.name))
+		goto partial;
+
+	if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
+		goto partial;
+
+	if (!trace_seq_puts(s, ")"))
+		goto partial;
+
+	for (i = 0; i < field->nargs; i++)
+		if (!trace_seq_printf(s, " %s=%lx",
+				      tp->args[i].name, field->args[i]))
+			goto partial;
+
+	if (!trace_seq_puts(s, "\n"))
+		goto partial;
+
+	return TRACE_TYPE_HANDLED;
+partial:
+	return TRACE_TYPE_PARTIAL_LINE;
+}
+
+enum print_line_t
+print_kretprobe_event(struct trace_iterator *iter, int flags)
+{
+	struct kretprobe_trace_entry *field;
+	struct trace_seq *s = &iter->seq;
+	struct trace_event *event;
+	struct trace_probe *tp;
+	int i;
+
+	field = (struct kretprobe_trace_entry *)iter->ent;
+	event = ftrace_find_event(field->ent.type);
+	tp = container_of(event, struct trace_probe, event);
+
+	if (!trace_seq_printf(s, "%s: (", tp->call.name))
+		goto partial;
+
+	if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
+		goto partial;
+
+	if (!trace_seq_puts(s, " <- "))
+		goto partial;
+
+	if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
+		goto partial;
+
+	if (!trace_seq_puts(s, ")"))
+		goto partial;
+
+	for (i = 0; i < field->nargs; i++)
+		if (!trace_seq_printf(s, " %s=%lx",
+				      tp->args[i].name, field->args[i]))
+			goto partial;
+
+	if (!trace_seq_puts(s, "\n"))
+		goto partial;
+
+	return TRACE_TYPE_HANDLED;
+partial:
+	return TRACE_TYPE_PARTIAL_LINE;
+}
+
+static int probe_event_enable(struct ftrace_event_call *call)
+{
+	struct trace_probe *tp = (struct trace_probe *)call->data;
+
+	tp->flags |= TP_FLAG_TRACE;
+	if (probe_is_return(tp))
+		return enable_kretprobe(&tp->rp);
+	else
+		return enable_kprobe(&tp->rp.kp);
+}
+
+static void probe_event_disable(struct ftrace_event_call *call)
+{
+	struct trace_probe *tp = (struct trace_probe *)call->data;
+
+	tp->flags &= ~TP_FLAG_TRACE;
+	if (!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE))) {
+		if (probe_is_return(tp))
+			disable_kretprobe(&tp->rp);
+		else
+			disable_kprobe(&tp->rp.kp);
+	}
+}
+
+static int probe_event_raw_init(struct ftrace_event_call *event_call)
+{
+	INIT_LIST_HEAD(&event_call->fields);
+
+	return 0;
+}
+
+#undef DEFINE_FIELD
+#define DEFINE_FIELD(type, item, name, is_signed)			\
+	do {								\
+		ret = trace_define_field(event_call, #type, name,	\
+					 offsetof(typeof(field), item),	\
+					 sizeof(field.item), is_signed, \
+					 FILTER_OTHER);			\
+		if (ret)						\
+			return ret;					\
+	} while (0)
+
+static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
+{
+	int ret, i;
+	struct kprobe_trace_entry field;
+	struct trace_probe *tp = (struct trace_probe *)event_call->data;
+
+	ret = trace_define_common_fields(event_call);
+	if (!ret)
+		return ret;
+
+	DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
+	DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);
+	/* Set argument names as fields */
+	for (i = 0; i < tp->nr_args; i++)
+		DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
+	return 0;
+}
+
+static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
+{
+	int ret, i;
+	struct kretprobe_trace_entry field;
+	struct trace_probe *tp = (struct trace_probe *)event_call->data;
+
+	ret = trace_define_common_fields(event_call);
+	if (!ret)
+		return ret;
+
+	DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
+	DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
+	DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);
+	/* Set argument names as fields */
+	for (i = 0; i < tp->nr_args; i++)
+		DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
+	return 0;
+}
+
+static int __probe_event_show_format(struct trace_seq *s,
+				     struct trace_probe *tp, const char *fmt,
+				     const char *arg)
+{
+	int i;
+
+	/* Show format */
+	if (!trace_seq_printf(s, "\nprint fmt: \"%s", fmt))
+		return 0;
+
+	for (i = 0; i < tp->nr_args; i++)
+		if (!trace_seq_printf(s, " %s=%%lx", tp->args[i].name))
+			return 0;
+
+	if (!trace_seq_printf(s, "\", %s", arg))
+		return 0;
+
+	for (i = 0; i < tp->nr_args; i++)
+		if (!trace_seq_printf(s, ", REC->%s", tp->args[i].name))
+			return 0;
+
+	return trace_seq_puts(s, "\n");
+}
+
+#undef SHOW_FIELD
+#define SHOW_FIELD(type, item, name)					\
+	do {								\
+		ret = trace_seq_printf(s, "\tfield: " #type " %s;\t"	\
+				"offset:%u;\tsize:%u;\n", name,		\
+				(unsigned int)offsetof(typeof(field), item),\
+				(unsigned int)sizeof(type));		\
+		if (!ret)						\
+			return 0;					\
+	} while (0)
+
+static int kprobe_event_show_format(struct ftrace_event_call *call,
+				    struct trace_seq *s)
+{
+	struct kprobe_trace_entry field __attribute__((unused));
+	int ret, i;
+	struct trace_probe *tp = (struct trace_probe *)call->data;
+
+	SHOW_FIELD(unsigned long, ip, FIELD_STRING_IP);
+	SHOW_FIELD(int, nargs, FIELD_STRING_NARGS);
+
+	/* Show fields */
+	for (i = 0; i < tp->nr_args; i++)
+		SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
+	trace_seq_puts(s, "\n");
+
+	return __probe_event_show_format(s, tp, "(%lx)",
+					 "REC->" FIELD_STRING_IP);
+}
+
+static int kretprobe_event_show_format(struct ftrace_event_call *call,
+				       struct trace_seq *s)
+{
+	struct kretprobe_trace_entry field __attribute__((unused));
+	int ret, i;
+	struct trace_probe *tp = (struct trace_probe *)call->data;
+
+	SHOW_FIELD(unsigned long, func, FIELD_STRING_FUNC);
+	SHOW_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP);
+	SHOW_FIELD(int, nargs, FIELD_STRING_NARGS);
+
+	/* Show fields */
+	for (i = 0; i < tp->nr_args; i++)
+		SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
+	trace_seq_puts(s, "\n");
+
+	return __probe_event_show_format(s, tp, "(%lx <- %lx)",
+					 "REC->" FIELD_STRING_FUNC
+					 ", REC->" FIELD_STRING_RETIP);
+}
+
+#ifdef CONFIG_EVENT_PROFILE
+
+/* Kprobe profile handler */
+static __kprobes int kprobe_profile_func(struct kprobe *kp,
+					 struct pt_regs *regs)
+{
+	struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
+	struct ftrace_event_call *call = &tp->call;
+	struct kprobe_trace_entry *entry;
+	struct trace_entry *ent;
+	int size, __size, i, pc, __cpu;
+	unsigned long irq_flags;
+	char *trace_buf;
+	char *raw_data;
+	int rctx;
+
+	pc = preempt_count();
+	__size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
+	size = ALIGN(__size + sizeof(u32), sizeof(u64));
+	size -= sizeof(u32);
+	if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
+		     "profile buffer not large enough"))
+		return 0;
+
+	/*
+	 * Protect the non nmi buffer
+	 * This also protects the rcu read side
+	 */
+	local_irq_save(irq_flags);
+
+	rctx = perf_swevent_get_recursion_context();
+	if (rctx < 0)
+		goto end_recursion;
+
+	__cpu = smp_processor_id();
+
+	if (in_nmi())
+		trace_buf = rcu_dereference(perf_trace_buf_nmi);
+	else
+		trace_buf = rcu_dereference(perf_trace_buf);
+
+	if (!trace_buf)
+		goto end;
+
+	raw_data = per_cpu_ptr(trace_buf, __cpu);
+
+	/* Zero dead bytes from alignment to avoid buffer leak to userspace */
+	*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
+	entry = (struct kprobe_trace_entry *)raw_data;
+	ent = &entry->ent;
+
+	tracing_generic_entry_update(ent, irq_flags, pc);
+	ent->type = call->id;
+	entry->nargs = tp->nr_args;
+	entry->ip = (unsigned long)kp->addr;
+	for (i = 0; i < tp->nr_args; i++)
+		entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
+	perf_tp_event(call->id, entry->ip, 1, entry, size);
+
+end:
+	perf_swevent_put_recursion_context(rctx);
+end_recursion:
+	local_irq_restore(irq_flags);
+
+	return 0;
+}
+
+/* Kretprobe profile handler */
+static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri,
+					    struct pt_regs *regs)
+{
+	struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
+	struct ftrace_event_call *call = &tp->call;
+	struct kretprobe_trace_entry *entry;
+	struct trace_entry *ent;
+	int size, __size, i, pc, __cpu;
+	unsigned long irq_flags;
+	char *trace_buf;
+	char *raw_data;
+	int rctx;
+
+	pc = preempt_count();
+	__size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
+	size = ALIGN(__size + sizeof(u32), sizeof(u64));
+	size -= sizeof(u32);
+	if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
+		     "profile buffer not large enough"))
+		return 0;
+
+	/*
+	 * Protect the non nmi buffer
+	 * This also protects the rcu read side
+	 */
+	local_irq_save(irq_flags);
+
+	rctx = perf_swevent_get_recursion_context();
+	if (rctx < 0)
+		goto end_recursion;
+
+	__cpu = smp_processor_id();
+
+	if (in_nmi())
+		trace_buf = rcu_dereference(perf_trace_buf_nmi);
+	else
+		trace_buf = rcu_dereference(perf_trace_buf);
+
+	if (!trace_buf)
+		goto end;
+
+	raw_data = per_cpu_ptr(trace_buf, __cpu);
+
+	/* Zero dead bytes from alignment to avoid buffer leak to userspace */
+	*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
+	entry = (struct kretprobe_trace_entry *)raw_data;
+	ent = &entry->ent;
+
+	tracing_generic_entry_update(ent, irq_flags, pc);
+	ent->type = call->id;
+	entry->nargs = tp->nr_args;
+	entry->func = (unsigned long)tp->rp.kp.addr;
+	entry->ret_ip = (unsigned long)ri->ret_addr;
+	for (i = 0; i < tp->nr_args; i++)
+		entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
+	perf_tp_event(call->id, entry->ret_ip, 1, entry, size);
+
+end:
+	perf_swevent_put_recursion_context(rctx);
+end_recursion:
+	local_irq_restore(irq_flags);
+
+	return 0;
+}
+
+static int probe_profile_enable(struct ftrace_event_call *call)
+{
+	struct trace_probe *tp = (struct trace_probe *)call->data;
+
+	tp->flags |= TP_FLAG_PROFILE;
+
+	if (probe_is_return(tp))
+		return enable_kretprobe(&tp->rp);
+	else
+		return enable_kprobe(&tp->rp.kp);
+}
+
+static void probe_profile_disable(struct ftrace_event_call *call)
+{
+	struct trace_probe *tp = (struct trace_probe *)call->data;
+
+	tp->flags &= ~TP_FLAG_PROFILE;
+
+	if (!(tp->flags & TP_FLAG_TRACE)) {
+		if (probe_is_return(tp))
+			disable_kretprobe(&tp->rp);
+		else
+			disable_kprobe(&tp->rp.kp);
+	}
+}
+#endif	/* CONFIG_EVENT_PROFILE */
+
+
+static __kprobes
+int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
+{
+	struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
+
+	if (tp->flags & TP_FLAG_TRACE)
+		kprobe_trace_func(kp, regs);
+#ifdef CONFIG_EVENT_PROFILE
+	if (tp->flags & TP_FLAG_PROFILE)
+		kprobe_profile_func(kp, regs);
+#endif	/* CONFIG_EVENT_PROFILE */
+	return 0;	/* We don't tweek kernel, so just return 0 */
+}
+
+static __kprobes
+int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
+{
+	struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
+
+	if (tp->flags & TP_FLAG_TRACE)
+		kretprobe_trace_func(ri, regs);
+#ifdef CONFIG_EVENT_PROFILE
+	if (tp->flags & TP_FLAG_PROFILE)
+		kretprobe_profile_func(ri, regs);
+#endif	/* CONFIG_EVENT_PROFILE */
+	return 0;	/* We don't tweek kernel, so just return 0 */
+}
+
+static int register_probe_event(struct trace_probe *tp)
+{
+	struct ftrace_event_call *call = &tp->call;
+	int ret;
+
+	/* Initialize ftrace_event_call */
+	if (probe_is_return(tp)) {
+		tp->event.trace = print_kretprobe_event;
+		call->raw_init = probe_event_raw_init;
+		call->show_format = kretprobe_event_show_format;
+		call->define_fields = kretprobe_event_define_fields;
+	} else {
+		tp->event.trace = print_kprobe_event;
+		call->raw_init = probe_event_raw_init;
+		call->show_format = kprobe_event_show_format;
+		call->define_fields = kprobe_event_define_fields;
+	}
+	call->event = &tp->event;
+	call->id = register_ftrace_event(&tp->event);
+	if (!call->id)
+		return -ENODEV;
+	call->enabled = 0;
+	call->regfunc = probe_event_enable;
+	call->unregfunc = probe_event_disable;
+
+#ifdef CONFIG_EVENT_PROFILE
+	atomic_set(&call->profile_count, -1);
+	call->profile_enable = probe_profile_enable;
+	call->profile_disable = probe_profile_disable;
+#endif
+	call->data = tp;
+	ret = trace_add_event_call(call);
+	if (ret) {
+		pr_info("Failed to register kprobe event: %s\n", call->name);
+		unregister_ftrace_event(&tp->event);
+	}
+	return ret;
+}
+
+static void unregister_probe_event(struct trace_probe *tp)
+{
+	/* tp->event is unregistered in trace_remove_event_call() */
+	trace_remove_event_call(&tp->call);
+}
+
+/* Make a debugfs interface for controling probe points */
+static __init int init_kprobe_trace(void)
+{
+	struct dentry *d_tracer;
+	struct dentry *entry;
+
+	d_tracer = tracing_init_dentry();
+	if (!d_tracer)
+		return 0;
+
+	entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
+				    NULL, &kprobe_events_ops);
+
+	/* Event list interface */
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'kprobe_events' entry\n");
+
+	/* Profile interface */
+	entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
+				    NULL, &kprobe_profile_ops);
+
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'kprobe_profile' entry\n");
+	return 0;
+}
+fs_initcall(init_kprobe_trace);
+
+
+#ifdef CONFIG_FTRACE_STARTUP_TEST
+
+static int kprobe_trace_selftest_target(int a1, int a2, int a3,
+					int a4, int a5, int a6)
+{
+	return a1 + a2 + a3 + a4 + a5 + a6;
+}
+
+static __init int kprobe_trace_self_tests_init(void)
+{
+	int ret;
+	int (*target)(int, int, int, int, int, int);
+
+	target = kprobe_trace_selftest_target;
+
+	pr_info("Testing kprobe tracing: ");
+
+	ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
+				  "$arg1 $arg2 $arg3 $arg4 $stack $stack0");
+	if (WARN_ON_ONCE(ret))
+		pr_warning("error enabling function entry\n");
+
+	ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
+				  "$retval");
+	if (WARN_ON_ONCE(ret))
+		pr_warning("error enabling function return\n");
+
+	ret = target(1, 2, 3, 4, 5, 6);
+
+	cleanup_all_probes();
+
+	pr_cont("OK\n");
+	return 0;
+}
+
+late_initcall(kprobe_trace_self_tests_init);
+
+#endif