/*
* 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 void 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 &&