first commit

1 files changed, 1023 insertions, 0 deletions

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
new file mode 100644
index 000000000..6fd72b768
--- /dev/null
+++ b/kernel/trace/trace_uprobe.c
@@ -0,0 +1,1023 @@
+/*
+ * uprobes-based tracing events
+ *
+ * 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
+ *
+ * Copyright (C) IBM Corporation, 2010-2012
+ * Author:	Srikar Dronamraju <srikar@linux.vnet.ibm.com>
+ */
+
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <linux/uprobes.h>
+#include <linux/namei.h>
+#include <linux/string.h>
+
+#include "trace_probe.h"
+
+#define UPROBE_EVENT_SYSTEM	"uprobes"
+
+struct uprobe_trace_entry_head {
+	struct trace_entry	ent;
+	unsigned long		vaddr[];
+};
+
+#define SIZEOF_TRACE_ENTRY(is_return)			\
+	(sizeof(struct uprobe_trace_entry_head) +	\
+	 sizeof(unsigned long) * (is_return ? 2 : 1))
+
+#define DATAOF_TRACE_ENTRY(entry, is_return)		\
+	((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))
+
+struct trace_uprobe_filter {
+	rwlock_t		rwlock;
+	int			nr_systemwide;
+	struct list_head	perf_events;
+};
+
+/*
+ * uprobe event core functions
+ */
+struct trace_uprobe {
+	struct list_head		list;
+	struct ftrace_event_class	class;
+	struct ftrace_event_call	call;
+	struct trace_uprobe_filter	filter;
+	struct uprobe_consumer		consumer;
+	struct inode			*inode;
+	char				*filename;
+	unsigned long			offset;
+	unsigned long			nhit;
+	unsigned int			flags;	/* For TP_FLAG_* */
+	ssize_t				size;	/* trace entry size */
+	unsigned int			nr_args;
+	struct probe_arg		args[];
+};
+
+#define SIZEOF_TRACE_UPROBE(n)			\
+	(offsetof(struct trace_uprobe, args) +	\
+	(sizeof(struct probe_arg) * (n)))
+
+static int register_uprobe_event(struct trace_uprobe *tu);
+static int unregister_uprobe_event(struct trace_uprobe *tu);
+
+static DEFINE_MUTEX(uprobe_lock);
+static LIST_HEAD(uprobe_list);
+
+static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
+static int uretprobe_dispatcher(struct uprobe_consumer *con,
+				unsigned long func, struct pt_regs *regs);
+
+static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
+{
+	rwlock_init(&filter->rwlock);
+	filter->nr_systemwide = 0;
+	INIT_LIST_HEAD(&filter->perf_events);
+}
+
+static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
+{
+	return !filter->nr_systemwide && list_empty(&filter->perf_events);
+}
+
+static inline bool is_ret_probe(struct trace_uprobe *tu)
+{
+	return tu->consumer.ret_handler != NULL;
+}
+
+/*
+ * Allocate new trace_uprobe and initialize it (including uprobes).
+ */
+static struct trace_uprobe *
+alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
+{
+	struct trace_uprobe *tu;
+
+	if (!event || !is_good_name(event))
+		return ERR_PTR(-EINVAL);
+
+	if (!group || !is_good_name(group))
+		return ERR_PTR(-EINVAL);
+
+	tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
+	if (!tu)
+		return ERR_PTR(-ENOMEM);
+
+	tu->call.class = &tu->class;
+	tu->call.name = kstrdup(event, GFP_KERNEL);
+	if (!tu->call.name)
+		goto error;
+
+	tu->class.system = kstrdup(group, GFP_KERNEL);
+	if (!tu->class.system)
+		goto error;
+
+	INIT_LIST_HEAD(&tu->list);
+	tu->consumer.handler = uprobe_dispatcher;
+	if (is_ret)
+		tu->consumer.ret_handler = uretprobe_dispatcher;
+	init_trace_uprobe_filter(&tu->filter);
+	return tu;
+
+error:
+	kfree(tu->call.name);
+	kfree(tu);
+
+	return ERR_PTR(-ENOMEM);
+}
+
+static void free_trace_uprobe(struct trace_uprobe *tu)
+{
+	int i;
+
+	for (i = 0; i < tu->nr_args; i++)
+		traceprobe_free_probe_arg(&tu->args[i]);
+
+	iput(tu->inode);
+	kfree(tu->call.class->system);
+	kfree(tu->call.name);
+	kfree(tu->filename);
+	kfree(tu);
+}
+
+static struct trace_uprobe *find_probe_event(const char *event, const char *group)
+{
+	struct trace_uprobe *tu;
+
+	list_for_each_entry(tu, &uprobe_list, list)
+		if (strcmp(tu->call.name, event) == 0 &&
+		    strcmp(tu->call.class->system, group) == 0)
+			return tu;
+
+	return NULL;
+}
+
+/* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
+static int unregister_trace_uprobe(struct trace_uprobe *tu)
+{
+	int ret;
+
+	ret = unregister_uprobe_event(tu);
+	if (ret)
+		return ret;
+
+	list_del(&tu->list);
+	free_trace_uprobe(tu);
+	return 0;
+}
+
+/* Register a trace_uprobe and probe_event */
+static int register_trace_uprobe(struct trace_uprobe *tu)
+{
+	struct trace_uprobe *old_tp;
+	int ret;
+
+	mutex_lock(&uprobe_lock);
+
+	/* register as an event */
+	old_tp = find_probe_event(tu->call.name, tu->call.class->system);
+	if (old_tp) {
+		/* delete old event */
+		ret = unregister_trace_uprobe(old_tp);
+		if (ret)
+			goto end;
+	}
+
+	ret = register_uprobe_event(tu);
+	if (ret) {
+		pr_warning("Failed to register probe event(%d)\n", ret);
+		goto end;
+	}
+
+	list_add_tail(&tu->list, &uprobe_list);
+
+end:
+	mutex_unlock(&uprobe_lock);
+
+	return ret;
+}
+
+/*
+ * Argument syntax:
+ *  - Add uprobe: p|r[:[GRP/]EVENT] PATH:SYMBOL [FETCHARGS]
+ *
+ *  - Remove uprobe: -:[GRP/]EVENT
+ */
+static int create_trace_uprobe(int argc, char **argv)
+{
+	struct trace_uprobe *tu;
+	struct inode *inode;
+	char *arg, *event, *group, *filename;
+	char buf[MAX_EVENT_NAME_LEN];
+	struct path path;
+	unsigned long offset;
+	bool is_delete, is_return;
+	int i, ret;
+
+	inode = NULL;
+	ret = 0;
+	is_delete = false;
+	is_return = false;
+	event = NULL;
+	group = NULL;
+
+	/* argc must be >= 1 */
+	if (argv[0][0] == '-')
+		is_delete = true;
+	else if (argv[0][0] == 'r')
+		is_return = true;
+	else if (argv[0][0] != 'p') {
+		pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");
+		return -EINVAL;
+	}
+
+	if (argv[0][1] == ':') {
+		event = &argv[0][2];
+		arg = strchr(event, '/');
+
+		if (arg) {
+			group = event;
+			event = arg + 1;
+			event[-1] = '\0';
+
+			if (strlen(group) == 0) {
+				pr_info("Group name is not specified\n");
+				return -EINVAL;
+			}
+		}
+		if (strlen(event) == 0) {
+			pr_info("Event name is not specified\n");
+			return -EINVAL;
+		}
+	}
+	if (!group)
+		group = UPROBE_EVENT_SYSTEM;
+
+	if (is_delete) {
+		int ret;
+
+		if (!event) {
+			pr_info("Delete command needs an event name.\n");
+			return -EINVAL;
+		}
+		mutex_lock(&uprobe_lock);
+		tu = find_probe_event(event, group);
+
+		if (!tu) {
+			mutex_unlock(&uprobe_lock);
+			pr_info("Event %s/%s doesn't exist.\n", group, event);
+			return -ENOENT;
+		}
+		/* delete an event */
+		ret = unregister_trace_uprobe(tu);
+		mutex_unlock(&uprobe_lock);
+		return ret;
+	}
+
+	if (argc < 2) {
+		pr_info("Probe point is not specified.\n");
+		return -EINVAL;
+	}
+	if (isdigit(argv[1][0])) {
+		pr_info("probe point must be have a filename.\n");
+		return -EINVAL;
+	}
+	arg = strchr(argv[1], ':');
+	if (!arg) {
+		ret = -EINVAL;
+		goto fail_address_parse;
+	}
+
+	*arg++ = '\0';
+	filename = argv[1];
+	ret = kern_path(filename, LOOKUP_FOLLOW, &path);
+	if (ret)
+		goto fail_address_parse;
+
+	inode = igrab(path.dentry->d_inode);
+	path_put(&path);
+
+	if (!inode || !S_ISREG(inode->i_mode)) {
+		ret = -EINVAL;
+		goto fail_address_parse;
+	}
+
+	ret = kstrtoul(arg, 0, &offset);
+	if (ret)
+		goto fail_address_parse;
+
+	argc -= 2;
+	argv += 2;
+
+	/* setup a probe */
+	if (!event) {
+		char *tail;
+		char *ptr;
+
+		tail = kstrdup(kbasename(filename), GFP_KERNEL);
+		if (!tail) {
+			ret = -ENOMEM;
+			goto fail_address_parse;
+		}
+
+		ptr = strpbrk(tail, ".-_");
+		if (ptr)
+			*ptr = '\0';
+
+		snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
+		event = buf;
+		kfree(tail);
+	}
+
+	tu = alloc_trace_uprobe(group, event, argc, is_return);
+	if (IS_ERR(tu)) {
+		pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
+		ret = PTR_ERR(tu);
+		goto fail_address_parse;
+	}
+	tu->offset = offset;
+	tu->inode = inode;
+	tu->filename = kstrdup(filename, GFP_KERNEL);
+
+	if (!tu->filename) {
+		pr_info("Failed to allocate filename.\n");
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	/* parse arguments */
+	ret = 0;
+	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
+		/* Increment count for freeing args in error case */
+		tu->nr_args++;
+
+		/* Parse argument name */
+		arg = strchr(argv[i], '=');
+		if (arg) {
+			*arg++ = '\0';
+			tu->args[i].name = kstrdup(argv[i], GFP_KERNEL);
+		} else {
+			arg = argv[i];
+			/* If argument name is omitted, set "argN" */
+			snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
+			tu->args[i].name = kstrdup(buf, GFP_KERNEL);
+		}
+
+		if (!tu->args[i].name) {
+			pr_info("Failed to allocate argument[%d] name.\n", i);
+			ret = -ENOMEM;
+			goto error;
+		}
+
+		if (!is_good_name(tu->args[i].name)) {
+			pr_info("Invalid argument[%d] name: %s\n", i, tu->args[i].name);
+			ret = -EINVAL;
+			goto error;
+		}
+
+		if (traceprobe_conflict_field_name(tu->args[i].name, tu->args, i)) {
+			pr_info("Argument[%d] name '%s' conflicts with "
+				"another field.\n", i, argv[i]);
+			ret = -EINVAL;
+			goto error;
+		}
+
+		/* Parse fetch argument */
+		ret = traceprobe_parse_probe_arg(arg, &tu->size, &tu->args[i], false, false);
+		if (ret) {
+			pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
+			goto error;
+		}
+	}
+
+	ret = register_trace_uprobe(tu);
+	if (ret)
+		goto error;
+	return 0;
+
+error:
+	free_trace_uprobe(tu);
+	return ret;
+
+fail_address_parse:
+	if (inode)
+		iput(inode);
+
+	pr_info("Failed to parse address or file.\n");
+
+	return ret;
+}
+
+static int cleanup_all_probes(void)
+{
+	struct trace_uprobe *tu;
+	int ret = 0;
+
+	mutex_lock(&uprobe_lock);
+	while (!list_empty(&uprobe_list)) {
+		tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
+		ret = unregister_trace_uprobe(tu);
+		if (ret)
+			break;
+	}
+	mutex_unlock(&uprobe_lock);
+	return ret;
+}
+
+/* Probes listing interfaces */
+static void *probes_seq_start(struct seq_file *m, loff_t *pos)
+{
+	mutex_lock(&uprobe_lock);
+	return seq_list_start(&uprobe_list, *pos);
+}
+
+static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	return seq_list_next(v, &uprobe_list, pos);
+}
+
+static void probes_seq_stop(struct seq_file *m, void *v)
+{
+	mutex_unlock(&uprobe_lock);
+}
+
+static int probes_seq_show(struct seq_file *m, void *v)
+{
+	struct trace_uprobe *tu = v;
+	char c = is_ret_probe(tu) ? 'r' : 'p';
+	int i;
+
+	seq_printf(m, "%c:%s/%s", c, tu->call.class->system, tu->call.name);
+	seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset);
+
+	for (i = 0; i < tu->nr_args; i++)
+		seq_printf(m, " %s=%s", tu->args[i].name, tu->args[i].comm);
+
+	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)
+{
+	int ret;
+
+	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
+		ret = cleanup_all_probes();
+		if (ret)
+			return ret;
+	}
+
+	return seq_open(file, &probes_seq_op);
+}
+
+static ssize_t probes_write(struct file *file, const char __user *buffer,
+			    size_t count, loff_t *ppos)
+{
+	return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe);
+}
+
+static const struct file_operations uprobe_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_uprobe *tu = v;
+
+	seq_printf(m, "  %s %-44s %15lu\n", tu->filename, tu->call.name, tu->nhit);
+	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 uprobe_profile_ops = {
+	.owner		= THIS_MODULE,
+	.open		= profile_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static void uprobe_trace_print(struct trace_uprobe *tu,
+				unsigned long func, struct pt_regs *regs)
+{
+	struct uprobe_trace_entry_head *entry;
+	struct ring_buffer_event *event;
+	struct ring_buffer *buffer;
+	void *data;
+	int size, i;
+	struct ftrace_event_call *call = &tu->call;
+
+	size = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
+	event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
+						  size + tu->size, 0, 0);
+	if (!event)
+		return;
+
+	entry = ring_buffer_event_data(event);
+	if (is_ret_probe(tu)) {
+		entry->vaddr[0] = func;
+		entry->vaddr[1] = instruction_pointer(regs);
+		data = DATAOF_TRACE_ENTRY(entry, true);
+	} else {
+		entry->vaddr[0] = instruction_pointer(regs);
+		data = DATAOF_TRACE_ENTRY(entry, false);
+	}
+
+	for (i = 0; i < tu->nr_args; i++)
+		call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
+
+	if (!filter_current_check_discard(buffer, call, entry, event))
+		trace_buffer_unlock_commit(buffer, event, 0, 0);
+}
+
+/* uprobe handler */
+static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
+{
+	if (!is_ret_probe(tu))
+		uprobe_trace_print(tu, 0, regs);
+	return 0;
+}
+
+static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
+				struct pt_regs *regs)
+{
+	uprobe_trace_print(tu, func, regs);
+}
+
+/* Event entry printers */
+static enum print_line_t
+print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
+{
+	struct uprobe_trace_entry_head *entry;
+	struct trace_seq *s = &iter->seq;
+	struct trace_uprobe *tu;
+	u8 *data;
+	int i;
+
+	entry = (struct uprobe_trace_entry_head *)iter->ent;
+	tu = container_of(event, struct trace_uprobe, call.event);
+
+	if (is_ret_probe(tu)) {
+		if (!trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", tu->call.name,
+					entry->vaddr[1], entry->vaddr[0]))
+			goto partial;
+		data = DATAOF_TRACE_ENTRY(entry, true);
+	} else {
+		if (!trace_seq_printf(s, "%s: (0x%lx)", tu->call.name,
+					entry->vaddr[0]))
+			goto partial;
+		data = DATAOF_TRACE_ENTRY(entry, false);
+	}
+
+	for (i = 0; i < tu->nr_args; i++) {
+		if (!tu->args[i].type->print(s, tu->args[i].name,
+					     data + tu->args[i].offset, entry))
+			goto partial;
+	}
+
+	if (trace_seq_puts(s, "\n"))
+		return TRACE_TYPE_HANDLED;
+
+partial:
+	return TRACE_TYPE_PARTIAL_LINE;
+}
+
+static inline bool is_trace_uprobe_enabled(struct trace_uprobe *tu)
+{
+	return tu->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE);
+}
+
+typedef bool (*filter_func_t)(struct uprobe_consumer *self,
+				enum uprobe_filter_ctx ctx,
+				struct mm_struct *mm);
+
+static int
+probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter)
+{
+	int ret = 0;
+
+	if (is_trace_uprobe_enabled(tu))
+		return -EINTR;
+
+	WARN_ON(!uprobe_filter_is_empty(&tu->filter));
+
+	tu->flags |= flag;
+	tu->consumer.filter = filter;
+	ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
+	if (ret)
+		tu->flags &= ~flag;
+
+	return ret;
+}
+
+static void probe_event_disable(struct trace_uprobe *tu, int flag)
+{
+	if (!is_trace_uprobe_enabled(tu))
+		return;
+
+	WARN_ON(!uprobe_filter_is_empty(&tu->filter));
+
+	uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
+	tu->flags &= ~flag;
+}
+
+static int uprobe_event_define_fields(struct ftrace_event_call *event_call)
+{
+	int ret, i, size;
+	struct uprobe_trace_entry_head field;
+	struct trace_uprobe *tu = event_call->data;
+
+	if (is_ret_probe(tu)) {
+		DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
+		DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
+		size = SIZEOF_TRACE_ENTRY(true);
+	} else {
+		DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
+		size = SIZEOF_TRACE_ENTRY(false);
+	}
+	/* Set argument names as fields */
+	for (i = 0; i < tu->nr_args; i++) {
+		ret = trace_define_field(event_call, tu->args[i].type->fmttype,
+					 tu->args[i].name,
+					 size + tu->args[i].offset,
+					 tu->args[i].type->size,
+					 tu->args[i].type->is_signed,
+					 FILTER_OTHER);
+
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+#define LEN_OR_ZERO		(len ? len - pos : 0)
+static int __set_print_fmt(struct trace_uprobe *tu, char *buf, int len)
+{
+	const char *fmt, *arg;
+	int i;
+	int pos = 0;
+
+	if (is_ret_probe(tu)) {
+		fmt = "(%lx <- %lx)";
+		arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
+	} else {
+		fmt = "(%lx)";
+		arg = "REC->" FIELD_STRING_IP;
+	}
+
+	/* When len=0, we just calculate the needed length */
+
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
+
+	for (i = 0; i < tu->nr_args; i++) {
+		pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
+				tu->args[i].name, tu->args[i].type->fmt);
+	}
+
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
+
+	for (i = 0; i < tu->nr_args; i++) {
+		pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
+				tu->args[i].name);
+	}
+
+	return pos;	/* return the length of print_fmt */
+}
+#undef LEN_OR_ZERO
+
+static int set_print_fmt(struct trace_uprobe *tu)
+{
+	char *print_fmt;
+	int len;
+
+	/* First: called with 0 length to calculate the needed length */
+	len = __set_print_fmt(tu, NULL, 0);
+	print_fmt = kmalloc(len + 1, GFP_KERNEL);
+	if (!print_fmt)
+		return -ENOMEM;
+
+	/* Second: actually write the @print_fmt */
+	__set_print_fmt(tu, print_fmt, len + 1);
+	tu->call.print_fmt = print_fmt;
+
+	return 0;
+}
+
+#ifdef CONFIG_PERF_EVENTS
+static bool
+__uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
+{
+	struct perf_event *event;
+
+	if (filter->nr_systemwide)
+		return true;
+
+	list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
+		if (event->hw.tp_target->mm == mm)
+			return true;
+	}
+
+	return false;
+}
+
+static inline bool
+uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
+{
+	return __uprobe_perf_filter(&tu->filter, event->hw.tp_target->mm);
+}
+
+static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
+{
+	bool done;
+
+	write_lock(&tu->filter.rwlock);
+	if (event->hw.tp_target) {
+		/*
+		 * event->parent != NULL means copy_process(), we can avoid
+		 * uprobe_apply(). current->mm must be probed and we can rely
+		 * on dup_mmap() which preserves the already installed bp's.
+		 *
+		 * attr.enable_on_exec means that exec/mmap will install the
+		 * breakpoints we need.
+		 */
+		done = tu->filter.nr_systemwide ||
+			event->parent || event->attr.enable_on_exec ||
+			uprobe_filter_event(tu, event);
+		list_add(&event->hw.tp_list, &tu->filter.perf_events);
+	} else {
+		done = tu->filter.nr_systemwide;
+		tu->filter.nr_systemwide++;
+	}
+	write_unlock(&tu->filter.rwlock);
+
+	if (!done)
+		uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
+
+	return 0;
+}
+
+static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
+{
+	bool done;
+
+	write_lock(&tu->filter.rwlock);
+	if (event->hw.tp_target) {
+		list_del(&event->hw.tp_list);
+		done = tu->filter.nr_systemwide ||
+			(event->hw.tp_target->flags & PF_EXITING) ||
+			uprobe_filter_event(tu, event);
+	} else {
+		tu->filter.nr_systemwide--;
+		done = tu->filter.nr_systemwide;
+	}
+	write_unlock(&tu->filter.rwlock);
+
+	if (!done)
+		uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
+
+	return 0;
+}
+
+static bool uprobe_perf_filter(struct uprobe_consumer *uc,
+				enum uprobe_filter_ctx ctx, struct mm_struct *mm)
+{
+	struct trace_uprobe *tu;
+	int ret;
+
+	tu = container_of(uc, struct trace_uprobe, consumer);
+	read_lock(&tu->filter.rwlock);
+	ret = __uprobe_perf_filter(&tu->filter, mm);
+	read_unlock(&tu->filter.rwlock);
+
+	return ret;
+}
+
+static void uprobe_perf_print(struct trace_uprobe *tu,
+				unsigned long func, struct pt_regs *regs)
+{
+	struct ftrace_event_call *call = &tu->call;
+	struct uprobe_trace_entry_head *entry;
+	struct hlist_head *head;
+	void *data;
+	int size, rctx, i;
+
+	size = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
+	size = ALIGN(size + tu->size + sizeof(u32), sizeof(u64)) - sizeof(u32);
+	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
+		return;
+
+	preempt_disable();
+	head = this_cpu_ptr(call->perf_events);
+	if (hlist_empty(head))
+		goto out;
+
+	entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
+	if (!entry)
+		goto out;
+
+	if (is_ret_probe(tu)) {
+		entry->vaddr[0] = func;
+		entry->vaddr[1] = instruction_pointer(regs);
+		data = DATAOF_TRACE_ENTRY(entry, true);
+	} else {
+		entry->vaddr[0] = instruction_pointer(regs);
+		data = DATAOF_TRACE_ENTRY(entry, false);
+	}
+
+	for (i = 0; i < tu->nr_args; i++)
+		call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
+
+	perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
+ out:
+	preempt_enable();
+}
+
+/* uprobe profile handler */
+static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
+{
+	if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
+		return UPROBE_HANDLER_REMOVE;
+
+	if (!is_ret_probe(tu))
+		uprobe_perf_print(tu, 0, regs);
+	return 0;
+}
+
+static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
+				struct pt_regs *regs)
+{
+	uprobe_perf_print(tu, func, regs);
+}
+#endif	/* CONFIG_PERF_EVENTS */
+
+static
+int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, void *data)
+{
+	struct trace_uprobe *tu = event->data;
+
+	switch (type) {
+	case TRACE_REG_REGISTER:
+		return probe_event_enable(tu, TP_FLAG_TRACE, NULL);
+
+	case TRACE_REG_UNREGISTER:
+		probe_event_disable(tu, TP_FLAG_TRACE);
+		return 0;
+
+#ifdef CONFIG_PERF_EVENTS
+	case TRACE_REG_PERF_REGISTER:
+		return probe_event_enable(tu, TP_FLAG_PROFILE, uprobe_perf_filter);
+
+	case TRACE_REG_PERF_UNREGISTER:
+		probe_event_disable(tu, TP_FLAG_PROFILE);
+		return 0;
+
+	case TRACE_REG_PERF_OPEN:
+		return uprobe_perf_open(tu, data);
+
+	case TRACE_REG_PERF_CLOSE:
+		return uprobe_perf_close(tu, data);
+
+#endif
+	default:
+		return 0;
+	}
+	return 0;
+}
+
+static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
+{
+	struct trace_uprobe *tu;
+	int ret = 0;
+
+	tu = container_of(con, struct trace_uprobe, consumer);
+	tu->nhit++;
+
+	if (tu->flags & TP_FLAG_TRACE)
+		ret |= uprobe_trace_func(tu, regs);
+
+#ifdef CONFIG_PERF_EVENTS
+	if (tu->flags & TP_FLAG_PROFILE)
+		ret |= uprobe_perf_func(tu, regs);
+#endif
+	return ret;
+}
+
+static int uretprobe_dispatcher(struct uprobe_consumer *con,
+				unsigned long func, struct pt_regs *regs)
+{
+	struct trace_uprobe *tu;
+
+	tu = container_of(con, struct trace_uprobe, consumer);
+
+	if (tu->flags & TP_FLAG_TRACE)
+		uretprobe_trace_func(tu, func, regs);
+
+#ifdef CONFIG_PERF_EVENTS
+	if (tu->flags & TP_FLAG_PROFILE)
+		uretprobe_perf_func(tu, func, regs);
+#endif
+	return 0;
+}
+
+static struct trace_event_functions uprobe_funcs = {
+	.trace		= print_uprobe_event
+};
+
+static int register_uprobe_event(struct trace_uprobe *tu)
+{
+	struct ftrace_event_call *call = &tu->call;
+	int ret;
+
+	/* Initialize ftrace_event_call */
+	INIT_LIST_HEAD(&call->class->fields);
+	call->event.funcs = &uprobe_funcs;
+	call->class->define_fields = uprobe_event_define_fields;
+
+	if (set_print_fmt(tu) < 0)
+		return -ENOMEM;
+
+	ret = register_ftrace_event(&call->event);
+	if (!ret) {
+		kfree(call->print_fmt);
+		return -ENODEV;
+	}
+	call->flags = 0;
+	call->class->reg = trace_uprobe_register;
+	call->data = tu;
+	ret = trace_add_event_call(call);
+
+	if (ret) {
+		pr_info("Failed to register uprobe event: %s\n", call->name);
+		kfree(call->print_fmt);
+		unregister_ftrace_event(&call->event);
+	}
+
+	return ret;
+}
+
+static int unregister_uprobe_event(struct trace_uprobe *tu)
+{
+	int ret;
+
+	/* tu->event is unregistered in trace_remove_event_call() */
+	ret = trace_remove_event_call(&tu->call);
+	if (ret)
+		return ret;
+	kfree(tu->call.print_fmt);
+	tu->call.print_fmt = NULL;
+	return 0;
+}
+
+/* Make a trace interface for controling probe points */
+static __init int init_uprobe_trace(void)
+{
+	struct dentry *d_tracer;
+
+	d_tracer = tracing_init_dentry();
+	if (!d_tracer)
+		return 0;
+
+	trace_create_file("uprobe_events", 0644, d_tracer,
+				    NULL, &uprobe_events_ops);
+	/* Profile interface */
+	trace_create_file("uprobe_profile", 0444, d_tracer,
+				    NULL, &uprobe_profile_ops);
+	return 0;
+}
+
+fs_initcall(init_uprobe_trace);