19 files changed, 1206 insertions, 0 deletions

diff --git a/samples/Kconfig b/samples/Kconfig
new file mode 100644
index 00000000000..8924f72f062
--- /dev/null
+++ b/samples/Kconfig
@@ -0,0 +1,47 @@
+menuconfig SAMPLES
+	bool "Sample kernel code"
+	help
+	  You can build and test sample kernel code here.
+
+if SAMPLES
+
+config SAMPLE_TRACEPOINTS
+	tristate "Build tracepoints examples -- loadable modules only"
+	depends on TRACEPOINTS && m
+	help
+	  This build tracepoints example modules.
+
+config SAMPLE_TRACE_EVENTS
+	tristate "Build trace_events examples -- loadable modules only"
+	depends on EVENT_TRACING && m
+	help
+	  This build trace event example modules.
+
+config SAMPLE_KOBJECT
+	tristate "Build kobject examples -- loadable modules only"
+	depends on m
+	help
+	  This config option will allow you to build a number of
+	  different kobject sample modules showing how to use kobjects,
+	  ksets, and ktypes properly.
+
+	  If in doubt, say "N" here.
+
+config SAMPLE_KPROBES
+	tristate "Build kprobes examples -- loadable modules only"
+	depends on KPROBES && m
+	help
+	  This build several kprobes example modules.
+
+config SAMPLE_KRETPROBES
+	tristate "Build kretprobes example -- loadable modules only"
+	default m
+	depends on SAMPLE_KPROBES && KRETPROBES
+
+config SAMPLE_HW_BREAKPOINT
+	tristate "Build kernel hardware breakpoint examples -- loadable module only"
+	depends on HAVE_HW_BREAKPOINT && m
+	help
+	  This builds kernel hardware breakpoint example modules.
+
+endif # SAMPLES
diff --git a/samples/Makefile b/samples/Makefile
new file mode 100644
index 00000000000..0f15e6d77fd
--- /dev/null
+++ b/samples/Makefile
@@ -0,0 +1,4 @@
+# Makefile for Linux samples code
+
+obj-$(CONFIG_SAMPLES)	+= kobject/ kprobes/ tracepoints/ trace_events/ \
+			   hw_breakpoint/
diff --git a/samples/hw_breakpoint/Makefile b/samples/hw_breakpoint/Makefile
new file mode 100644
index 00000000000..0f5c31c2fc4
--- /dev/null
+++ b/samples/hw_breakpoint/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_SAMPLE_HW_BREAKPOINT) += data_breakpoint.o
diff --git a/samples/hw_breakpoint/data_breakpoint.c b/samples/hw_breakpoint/data_breakpoint.c
new file mode 100644
index 00000000000..c69cbe9b242
--- /dev/null
+++ b/samples/hw_breakpoint/data_breakpoint.c
@@ -0,0 +1,90 @@
+/*
+ * data_breakpoint.c - Sample HW Breakpoint file to watch kernel data address
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * usage: insmod data_breakpoint.ko ksym=<ksym_name>
+ *
+ * This file is a kernel module that places a breakpoint over ksym_name kernel
+ * variable using Hardware Breakpoint register. The corresponding handler which
+ * prints a backtrace is invoked everytime a write operation is performed on
+ * that variable.
+ *
+ * Copyright (C) IBM Corporation, 2009
+ *
+ * Author: K.Prasad <prasad@linux.vnet.ibm.com>
+ */
+#include <linux/module.h>	/* Needed by all modules */
+#include <linux/kernel.h>	/* Needed for KERN_INFO */
+#include <linux/init.h>		/* Needed for the macros */
+#include <linux/kallsyms.h>
+
+#include <linux/perf_event.h>
+#include <linux/hw_breakpoint.h>
+
+struct perf_event **sample_hbp;
+
+static char ksym_name[KSYM_NAME_LEN] = "pid_max";
+module_param_string(ksym, ksym_name, KSYM_NAME_LEN, S_IRUGO);
+MODULE_PARM_DESC(ksym, "Kernel symbol to monitor; this module will report any"
+			" write operations on the kernel symbol");
+
+static void sample_hbp_handler(struct perf_event *bp, int nmi,
+			       struct perf_sample_data *data,
+			       struct pt_regs *regs)
+{
+	printk(KERN_INFO "%s value is changed\n", ksym_name);
+	dump_stack();
+	printk(KERN_INFO "Dump stack from sample_hbp_handler\n");
+}
+
+static int __init hw_break_module_init(void)
+{
+	int ret;
+	struct perf_event_attr attr;
+
+	hw_breakpoint_init(&attr);
+	attr.bp_addr = kallsyms_lookup_name(ksym_name);
+	attr.bp_len = HW_BREAKPOINT_LEN_4;
+	attr.bp_type = HW_BREAKPOINT_W | HW_BREAKPOINT_R;
+
+	sample_hbp = register_wide_hw_breakpoint(&attr, sample_hbp_handler);
+	if (IS_ERR(sample_hbp)) {
+		ret = PTR_ERR(sample_hbp);
+		goto fail;
+	}
+
+	printk(KERN_INFO "HW Breakpoint for %s write installed\n", ksym_name);
+
+	return 0;
+
+fail:
+	printk(KERN_INFO "Breakpoint registration failed\n");
+
+	return ret;
+}
+
+static void __exit hw_break_module_exit(void)
+{
+	unregister_wide_hw_breakpoint(sample_hbp);
+	printk(KERN_INFO "HW Breakpoint for %s write uninstalled\n", ksym_name);
+}
+
+module_init(hw_break_module_init);
+module_exit(hw_break_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("K.Prasad");
+MODULE_DESCRIPTION("ksym breakpoint");
diff --git a/samples/kobject/Makefile b/samples/kobject/Makefile
new file mode 100644
index 00000000000..4a194203c98
--- /dev/null
+++ b/samples/kobject/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_SAMPLE_KOBJECT) += kobject-example.o kset-example.o
diff --git a/samples/kobject/kobject-example.c b/samples/kobject/kobject-example.c
new file mode 100644
index 00000000000..8d9b55a1202
--- /dev/null
+++ b/samples/kobject/kobject-example.c
@@ -0,0 +1,137 @@
+/*
+ * Sample kobject implementation
+ *
+ * Copyright (C) 2004-2007 Greg Kroah-Hartman <greg@kroah.com>
+ * Copyright (C) 2007 Novell Inc.
+ *
+ * Released under the GPL version 2 only.
+ *
+ */
+#include <linux/kobject.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/module.h>
+#include <linux/init.h>
+
+/*
+ * This module shows how to create a simple subdirectory in sysfs called
+ * /sys/kernel/kobject-example  In that directory, 3 files are created:
+ * "foo", "baz", and "bar".  If an integer is written to these files, it can be
+ * later read out of it.
+ */
+
+static int foo;
+static int baz;
+static int bar;
+
+/*
+ * The "foo" file where a static variable is read from and written to.
+ */
+static ssize_t foo_show(struct kobject *kobj, struct kobj_attribute *attr,
+			char *buf)
+{
+	return sprintf(buf, "%d\n", foo);
+}
+
+static ssize_t foo_store(struct kobject *kobj, struct kobj_attribute *attr,
+			 const char *buf, size_t count)
+{
+	sscanf(buf, "%du", &foo);
+	return count;
+}
+
+static struct kobj_attribute foo_attribute =
+	__ATTR(foo, 0666, foo_show, foo_store);
+
+/*
+ * More complex function where we determine which varible is being accessed by
+ * looking at the attribute for the "baz" and "bar" files.
+ */
+static ssize_t b_show(struct kobject *kobj, struct kobj_attribute *attr,
+		      char *buf)
+{
+	int var;
+
+	if (strcmp(attr->attr.name, "baz") == 0)
+		var = baz;
+	else
+		var = bar;
+	return sprintf(buf, "%d\n", var);
+}
+
+static ssize_t b_store(struct kobject *kobj, struct kobj_attribute *attr,
+		       const char *buf, size_t count)
+{
+	int var;
+
+	sscanf(buf, "%du", &var);
+	if (strcmp(attr->attr.name, "baz") == 0)
+		baz = var;
+	else
+		bar = var;
+	return count;
+}
+
+static struct kobj_attribute baz_attribute =
+	__ATTR(baz, 0666, b_show, b_store);
+static struct kobj_attribute bar_attribute =
+	__ATTR(bar, 0666, b_show, b_store);
+
+
+/*
+ * Create a group of attributes so that we can create and destory them all
+ * at once.
+ */
+static struct attribute *attrs[] = {
+	&foo_attribute.attr,
+	&baz_attribute.attr,
+	&bar_attribute.attr,
+	NULL,	/* need to NULL terminate the list of attributes */
+};
+
+/*
+ * An unnamed attribute group will put all of the attributes directly in
+ * the kobject directory.  If we specify a name, a subdirectory will be
+ * created for the attributes with the directory being the name of the
+ * attribute group.
+ */
+static struct attribute_group attr_group = {
+	.attrs = attrs,
+};
+
+static struct kobject *example_kobj;
+
+static int __init example_init(void)
+{
+	int retval;
+
+	/*
+	 * Create a simple kobject with the name of "kobject_example",
+	 * located under /sys/kernel/
+	 *
+	 * As this is a simple directory, no uevent will be sent to
+	 * userspace.  That is why this function should not be used for
+	 * any type of dynamic kobjects, where the name and number are
+	 * not known ahead of time.
+	 */
+	example_kobj = kobject_create_and_add("kobject_example", kernel_kobj);
+	if (!example_kobj)
+		return -ENOMEM;
+
+	/* Create the files associated with this kobject */
+	retval = sysfs_create_group(example_kobj, &attr_group);
+	if (retval)
+		kobject_put(example_kobj);
+
+	return retval;
+}
+
+static void __exit example_exit(void)
+{
+	kobject_put(example_kobj);
+}
+
+module_init(example_init);
+module_exit(example_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Greg Kroah-Hartman <greg@kroah.com>");
diff --git a/samples/kobject/kset-example.c b/samples/kobject/kset-example.c
new file mode 100644
index 00000000000..45b7d56fb54
--- /dev/null
+++ b/samples/kobject/kset-example.c
@@ -0,0 +1,278 @@
+/*
+ * Sample kset and ktype implementation
+ *
+ * Copyright (C) 2004-2007 Greg Kroah-Hartman <greg@kroah.com>
+ * Copyright (C) 2007 Novell Inc.
+ *
+ * Released under the GPL version 2 only.
+ *
+ */
+#include <linux/kobject.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/module.h>
+#include <linux/init.h>
+
+/*
+ * This module shows how to create a kset in sysfs called
+ * /sys/kernel/kset-example
+ * Then tree kobjects are created and assigned to this kset, "foo", "baz",
+ * and "bar".  In those kobjects, attributes of the same name are also
+ * created and if an integer is written to these files, it can be later
+ * read out of it.
+ */
+
+
+/*
+ * This is our "object" that we will create a few of and register them with
+ * sysfs.
+ */
+struct foo_obj {
+	struct kobject kobj;
+	int foo;
+	int baz;
+	int bar;
+};
+#define to_foo_obj(x) container_of(x, struct foo_obj, kobj)
+
+/* a custom attribute that works just for a struct foo_obj. */
+struct foo_attribute {
+	struct attribute attr;
+	ssize_t (*show)(struct foo_obj *foo, struct foo_attribute *attr, char *buf);
+	ssize_t (*store)(struct foo_obj *foo, struct foo_attribute *attr, const char *buf, size_t count);
+};
+#define to_foo_attr(x) container_of(x, struct foo_attribute, attr)
+
+/*
+ * The default show function that must be passed to sysfs.  This will be
+ * called by sysfs for whenever a show function is called by the user on a
+ * sysfs file associated with the kobjects we have registered.  We need to
+ * transpose back from a "default" kobject to our custom struct foo_obj and
+ * then call the show function for that specific object.
+ */
+static ssize_t foo_attr_show(struct kobject *kobj,
+			     struct attribute *attr,
+			     char *buf)
+{
+	struct foo_attribute *attribute;
+	struct foo_obj *foo;
+
+	attribute = to_foo_attr(attr);
+	foo = to_foo_obj(kobj);
+
+	if (!attribute->show)
+		return -EIO;
+
+	return attribute->show(foo, attribute, buf);
+}
+
+/*
+ * Just like the default show function above, but this one is for when the
+ * sysfs "store" is requested (when a value is written to a file.)
+ */
+static ssize_t foo_attr_store(struct kobject *kobj,
+			      struct attribute *attr,
+			      const char *buf, size_t len)
+{
+	struct foo_attribute *attribute;
+	struct foo_obj *foo;
+
+	attribute = to_foo_attr(attr);
+	foo = to_foo_obj(kobj);
+
+	if (!attribute->store)
+		return -EIO;
+
+	return attribute->store(foo, attribute, buf, len);
+}
+
+/* Our custom sysfs_ops that we will associate with our ktype later on */
+static struct sysfs_ops foo_sysfs_ops = {
+	.show = foo_attr_show,
+	.store = foo_attr_store,
+};
+
+/*
+ * The release function for our object.  This is REQUIRED by the kernel to
+ * have.  We free the memory held in our object here.
+ *
+ * NEVER try to get away with just a "blank" release function to try to be
+ * smarter than the kernel.  Turns out, no one ever is...
+ */
+static void foo_release(struct kobject *kobj)
+{
+	struct foo_obj *foo;
+
+	foo = to_foo_obj(kobj);
+	kfree(foo);
+}
+
+/*
+ * The "foo" file where the .foo variable is read from and written to.
+ */
+static ssize_t foo_show(struct foo_obj *foo_obj, struct foo_attribute *attr,
+			char *buf)
+{
+	return sprintf(buf, "%d\n", foo_obj->foo);
+}
+
+static ssize_t foo_store(struct foo_obj *foo_obj, struct foo_attribute *attr,
+			 const char *buf, size_t count)
+{
+	sscanf(buf, "%du", &foo_obj->foo);
+	return count;
+}
+
+static struct foo_attribute foo_attribute =
+	__ATTR(foo, 0666, foo_show, foo_store);
+
+/*
+ * More complex function where we determine which varible is being accessed by
+ * looking at the attribute for the "baz" and "bar" files.
+ */
+static ssize_t b_show(struct foo_obj *foo_obj, struct foo_attribute *attr,
+		      char *buf)
+{
+	int var;
+
+	if (strcmp(attr->attr.name, "baz") == 0)
+		var = foo_obj->baz;
+	else
+		var = foo_obj->bar;
+	return sprintf(buf, "%d\n", var);
+}
+
+static ssize_t b_store(struct foo_obj *foo_obj, struct foo_attribute *attr,
+		       const char *buf, size_t count)
+{
+	int var;
+
+	sscanf(buf, "%du", &var);
+	if (strcmp(attr->attr.name, "baz") == 0)
+		foo_obj->baz = var;
+	else
+		foo_obj->bar = var;
+	return count;
+}
+
+static struct foo_attribute baz_attribute =
+	__ATTR(baz, 0666, b_show, b_store);
+static struct foo_attribute bar_attribute =
+	__ATTR(bar, 0666, b_show, b_store);
+
+/*
+ * Create a group of attributes so that we can create and destory them all
+ * at once.
+ */
+static struct attribute *foo_default_attrs[] = {
+	&foo_attribute.attr,
+	&baz_attribute.attr,
+	&bar_attribute.attr,
+	NULL,	/* need to NULL terminate the list of attributes */
+};
+
+/*
+ * Our own ktype for our kobjects.  Here we specify our sysfs ops, the
+ * release function, and the set of default attributes we want created
+ * whenever a kobject of this type is registered with the kernel.
+ */
+static struct kobj_type foo_ktype = {
+	.sysfs_ops = &foo_sysfs_ops,
+	.release = foo_release,
+	.default_attrs = foo_default_attrs,
+};
+
+static struct kset *example_kset;
+static struct foo_obj *foo_obj;
+static struct foo_obj *bar_obj;
+static struct foo_obj *baz_obj;
+
+static struct foo_obj *create_foo_obj(const char *name)
+{
+	struct foo_obj *foo;
+	int retval;
+
+	/* allocate the memory for the whole object */
+	foo = kzalloc(sizeof(*foo), GFP_KERNEL);
+	if (!foo)
+		return NULL;
+
+	/*
+	 * As we have a kset for this kobject, we need to set it before calling
+	 * the kobject core.
+	 */
+	foo->kobj.kset = example_kset;
+
+	/*
+	 * Initialize and add the kobject to the kernel.  All the default files
+	 * will be created here.  As we have already specified a kset for this
+	 * kobject, we don't have to set a parent for the kobject, the kobject
+	 * will be placed beneath that kset automatically.
+	 */
+	retval = kobject_init_and_add(&foo->kobj, &foo_ktype, NULL, "%s", name);
+	if (retval) {
+		kobject_put(&foo->kobj);
+		return NULL;
+	}
+
+	/*
+	 * We are always responsible for sending the uevent that the kobject
+	 * was added to the system.
+	 */
+	kobject_uevent(&foo->kobj, KOBJ_ADD);
+
+	return foo;
+}
+
+static void destroy_foo_obj(struct foo_obj *foo)
+{
+	kobject_put(&foo->kobj);
+}
+
+static int __init example_init(void)
+{
+	/*
+	 * Create a kset with the name of "kset_example",
+	 * located under /sys/kernel/
+	 */
+	example_kset = kset_create_and_add("kset_example", NULL, kernel_kobj);
+	if (!example_kset)
+		return -ENOMEM;
+
+	/*
+	 * Create three objects and register them with our kset
+	 */
+	foo_obj = create_foo_obj("foo");
+	if (!foo_obj)
+		goto foo_error;
+
+	bar_obj = create_foo_obj("bar");
+	if (!bar_obj)
+		goto bar_error;
+
+	baz_obj = create_foo_obj("baz");
+	if (!baz_obj)
+		goto baz_error;
+
+	return 0;
+
+baz_error:
+	destroy_foo_obj(bar_obj);
+bar_error:
+	destroy_foo_obj(foo_obj);
+foo_error:
+	return -EINVAL;
+}
+
+static void __exit example_exit(void)
+{
+	destroy_foo_obj(baz_obj);
+	destroy_foo_obj(bar_obj);
+	destroy_foo_obj(foo_obj);
+	kset_unregister(example_kset);
+}
+
+module_init(example_init);
+module_exit(example_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Greg Kroah-Hartman <greg@kroah.com>");
diff --git a/samples/kprobes/Makefile b/samples/kprobes/Makefile
new file mode 100644
index 00000000000..68739bc4fc6
--- /dev/null
+++ b/samples/kprobes/Makefile
@@ -0,0 +1,5 @@
+# builds the kprobes example kernel modules;
+# then to use one (as root):  insmod <module_name.ko>
+
+obj-$(CONFIG_SAMPLE_KPROBES) += kprobe_example.o jprobe_example.o
+obj-$(CONFIG_SAMPLE_KRETPROBES) += kretprobe_example.o
diff --git a/samples/kprobes/jprobe_example.c b/samples/kprobes/jprobe_example.c
new file mode 100644
index 00000000000..b7541355b92
--- /dev/null
+++ b/samples/kprobes/jprobe_example.c
@@ -0,0 +1,68 @@
+/*
+ * Here's a sample kernel module showing the use of jprobes to dump
+ * the arguments of do_fork().
+ *
+ * For more information on theory of operation of jprobes, see
+ * Documentation/kprobes.txt
+ *
+ * Build and insert the kernel module as done in the kprobe example.
+ * You will see the trace data in /var/log/messages and on the
+ * console whenever do_fork() is invoked to create a new process.
+ * (Some messages may be suppressed if syslogd is configured to
+ * eliminate duplicate messages.)
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/kprobes.h>
+
+/*
+ * Jumper probe for do_fork.
+ * Mirror principle enables access to arguments of the probed routine
+ * from the probe handler.
+ */
+
+/* Proxy routine having the same arguments as actual do_fork() routine */
+static long jdo_fork(unsigned long clone_flags, unsigned long stack_start,
+	      struct pt_regs *regs, unsigned long stack_size,
+	      int __user *parent_tidptr, int __user *child_tidptr)
+{
+	printk(KERN_INFO "jprobe: clone_flags = 0x%lx, stack_size = 0x%lx,"
+			" regs = 0x%p\n",
+	       clone_flags, stack_size, regs);
+
+	/* Always end with a call to jprobe_return(). */
+	jprobe_return();
+	return 0;
+}
+
+static struct jprobe my_jprobe = {
+	.entry			= jdo_fork,
+	.kp = {
+		.symbol_name	= "do_fork",
+	},
+};
+
+static int __init jprobe_init(void)
+{
+	int ret;
+
+	ret = register_jprobe(&my_jprobe);
+	if (ret < 0) {
+		printk(KERN_INFO "register_jprobe failed, returned %d\n", ret);
+		return -1;
+	}
+	printk(KERN_INFO "Planted jprobe at %p, handler addr %p\n",
+	       my_jprobe.kp.addr, my_jprobe.entry);
+	return 0;
+}
+
+static void __exit jprobe_exit(void)
+{
+	unregister_jprobe(&my_jprobe);
+	printk(KERN_INFO "jprobe at %p unregistered\n", my_jprobe.kp.addr);
+}
+
+module_init(jprobe_init)
+module_exit(jprobe_exit)
+MODULE_LICENSE("GPL");
diff --git a/samples/kprobes/kprobe_example.c b/samples/kprobes/kprobe_example.c
new file mode 100644
index 00000000000..a681998a871
--- /dev/null
+++ b/samples/kprobes/kprobe_example.c
@@ -0,0 +1,91 @@
+/*
+ * NOTE: This example is works on x86 and powerpc.
+ * Here's a sample kernel module showing the use of kprobes to dump a
+ * stack trace and selected registers when do_fork() is called.
+ *
+ * For more information on theory of operation of kprobes, see
+ * Documentation/kprobes.txt
+ *
+ * You will see the trace data in /var/log/messages and on the console
+ * whenever do_fork() is invoked to create a new process.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/kprobes.h>
+
+/* For each probe you need to allocate a kprobe structure */
+static struct kprobe kp = {
+	.symbol_name	= "do_fork",
+};
+
+/* kprobe pre_handler: called just before the probed instruction is executed */
+static int handler_pre(struct kprobe *p, struct pt_regs *regs)
+{
+#ifdef CONFIG_X86
+	printk(KERN_INFO "pre_handler: p->addr = 0x%p, ip = %lx,"
+			" flags = 0x%lx\n",
+		p->addr, regs->ip, regs->flags);
+#endif
+#ifdef CONFIG_PPC
+	printk(KERN_INFO "pre_handler: p->addr = 0x%p, nip = 0x%lx,"
+			" msr = 0x%lx\n",
+		p->addr, regs->nip, regs->msr);
+#endif
+
+	/* A dump_stack() here will give a stack backtrace */
+	return 0;
+}
+
+/* kprobe post_handler: called after the probed instruction is executed */
+static void handler_post(struct kprobe *p, struct pt_regs *regs,
+				unsigned long flags)
+{
+#ifdef CONFIG_X86
+	printk(KERN_INFO "post_handler: p->addr = 0x%p, flags = 0x%lx\n",
+		p->addr, regs->flags);
+#endif
+#ifdef CONFIG_PPC
+	printk(KERN_INFO "post_handler: p->addr = 0x%p, msr = 0x%lx\n",
+		p->addr, regs->msr);
+#endif
+}
+
+/*
+ * fault_handler: this is called if an exception is generated for any
+ * instruction within the pre- or post-handler, or when Kprobes
+ * single-steps the probed instruction.
+ */
+static int handler_fault(struct kprobe *p, struct pt_regs *regs, int trapnr)
+{
+	printk(KERN_INFO "fault_handler: p->addr = 0x%p, trap #%dn",
+		p->addr, trapnr);
+	/* Return 0 because we don't handle the fault. */
+	return 0;
+}
+
+static int __init kprobe_init(void)
+{
+	int ret;
+	kp.pre_handler = handler_pre;
+	kp.post_handler = handler_post;
+	kp.fault_handler = handler_fault;
+
+	ret = register_kprobe(&kp);
+	if (ret < 0) {
+		printk(KERN_INFO "register_kprobe failed, returned %d\n", ret);
+		return ret;
+	}
+	printk(KERN_INFO "Planted kprobe at %p\n", kp.addr);
+	return 0;
+}
+
+static void __exit kprobe_exit(void)
+{
+	unregister_kprobe(&kp);
+	printk(KERN_INFO "kprobe at %p unregistered\n", kp.addr);
+}
+
+module_init(kprobe_init)
+module_exit(kprobe_exit)
+MODULE_LICENSE("GPL");
diff --git a/samples/kprobes/kretprobe_example.c b/samples/kprobes/kretprobe_example.c
new file mode 100644
index 00000000000..1041b673159
--- /dev/null
+++ b/samples/kprobes/kretprobe_example.c
@@ -0,0 +1,107 @@
+/*
+ * kretprobe_example.c
+ *
+ * Here's a sample kernel module showing the use of return probes to
+ * report the return value and total time taken for probed function
+ * to run.
+ *
+ * usage: insmod kretprobe_example.ko func=<func_name>
+ *
+ * If no func_name is specified, do_fork is instrumented
+ *
+ * For more information on theory of operation of kretprobes, see
+ * Documentation/kprobes.txt
+ *
+ * Build and insert the kernel module as done in the kprobe example.
+ * You will see the trace data in /var/log/messages and on the console
+ * whenever the probed function returns. (Some messages may be suppressed
+ * if syslogd is configured to eliminate duplicate messages.)
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/kprobes.h>
+#include <linux/ktime.h>
+#include <linux/limits.h>
+#include <linux/sched.h>
+
+static char func_name[NAME_MAX] = "do_fork";
+module_param_string(func, func_name, NAME_MAX, S_IRUGO);
+MODULE_PARM_DESC(func, "Function to kretprobe; this module will report the"
+			" function's execution time");
+
+/* per-instance private data */
+struct my_data {
+	ktime_t entry_stamp;
+};
+
+/* Here we use the entry_hanlder to timestamp function entry */
+static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
+{
+	struct my_data *data;
+
+	if (!current->mm)
+		return 1;	/* Skip kernel threads */
+
+	data = (struct my_data *)ri->data;
+	data->entry_stamp = ktime_get();
+	return 0;
+}
+
+/*
+ * Return-probe handler: Log the return value and duration. Duration may turn
+ * out to be zero consistently, depending upon the granularity of time
+ * accounting on the platform.
+ */
+static int ret_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
+{
+	int retval = regs_return_value(regs);
+	struct my_data *data = (struct my_data *)ri->data;
+	s64 delta;
+	ktime_t now;
+
+	now = ktime_get();
+	delta = ktime_to_ns(ktime_sub(now, data->entry_stamp));
+	printk(KERN_INFO "%s returned %d and took %lld ns to execute\n",
+			func_name, retval, (long long)delta);
+	return 0;
+}
+
+static struct kretprobe my_kretprobe = {
+	.handler		= ret_handler,
+	.entry_handler		= entry_handler,
+	.data_size		= sizeof(struct my_data),
+	/* Probe up to 20 instances concurrently. */
+	.maxactive		= 20,
+};
+
+static int __init kretprobe_init(void)
+{
+	int ret;
+
+	my_kretprobe.kp.symbol_name = func_name;
+	ret = register_kretprobe(&my_kretprobe);
+	if (ret < 0) {
+		printk(KERN_INFO "register_kretprobe failed, returned %d\n",
+				ret);
+		return -1;
+	}
+	printk(KERN_INFO "Planted return probe at %s: %p\n",
+			my_kretprobe.kp.symbol_name, my_kretprobe.kp.addr);
+	return 0;
+}
+
+static void __exit kretprobe_exit(void)
+{
+	unregister_kretprobe(&my_kretprobe);
+	printk(KERN_INFO "kretprobe at %p unregistered\n",
+			my_kretprobe.kp.addr);
+
+	/* nmissed > 0 suggests that maxactive was set too low. */
+	printk(KERN_INFO "Missed probing %d instances of %s\n",
+		my_kretprobe.nmissed, my_kretprobe.kp.symbol_name);
+}
+
+module_init(kretprobe_init)
+module_exit(kretprobe_exit)
+MODULE_LICENSE("GPL");
diff --git a/samples/trace_events/Makefile b/samples/trace_events/Makefile
new file mode 100644
index 00000000000..0f8d92120c4
--- /dev/null
+++ b/samples/trace_events/Makefile
@@ -0,0 +1,14 @@
+# builds the trace events example kernel modules;
+# then to use one (as root):  insmod <module_name.ko>
+
+# If you include a trace header outside of include/trace/events
+# then the file that does the #define CREATE_TRACE_POINTS must
+# have that tracer file in its main search path. This is because
+# define_trace.h will include it, and must be able to find it from
+# the include/trace directory.
+#
+# Here trace-events-sample.c does the CREATE_TRACE_POINTS.
+#
+CFLAGS_trace-events-sample.o := -I$(src)
+
+obj-$(CONFIG_SAMPLE_TRACE_EVENTS) += trace-events-sample.o
diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c
new file mode 100644
index 00000000000..aabc4e97091
--- /dev/null
+++ b/samples/trace_events/trace-events-sample.c
@@ -0,0 +1,52 @@
+#include <linux/module.h>
+#include <linux/kthread.h>
+
+/*
+ * Any file that uses trace points, must include the header.
+ * But only one file, must include the header by defining
+ * CREATE_TRACE_POINTS first.  This will make the C code that
+ * creates the handles for the trace points.
+ */
+#define CREATE_TRACE_POINTS
+#include "trace-events-sample.h"
+
+
+static void simple_thread_func(int cnt)
+{
+	set_current_state(TASK_INTERRUPTIBLE);
+	schedule_timeout(HZ);
+	trace_foo_bar("hello", cnt);
+}
+
+static int simple_thread(void *arg)
+{
+	int cnt = 0;
+
+	while (!kthread_should_stop())
+		simple_thread_func(cnt++);
+
+	return 0;
+}
+
+static struct task_struct *simple_tsk;
+
+static int __init trace_event_init(void)
+{
+	simple_tsk = kthread_run(simple_thread, NULL, "event-sample");
+	if (IS_ERR(simple_tsk))
+		return -1;
+
+	return 0;
+}
+
+static void __exit trace_event_exit(void)
+{
+	kthread_stop(simple_tsk);
+}
+
+module_init(trace_event_init);
+module_exit(trace_event_exit);
+
+MODULE_AUTHOR("Steven Rostedt");
+MODULE_DESCRIPTION("trace-events-sample");
+MODULE_LICENSE("GPL");
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
new file mode 100644
index 00000000000..6af373236d7
--- /dev/null
+++ b/samples/trace_events/trace-events-sample.h
@@ -0,0 +1,137 @@
+/*
+ * If TRACE_SYSTEM is defined, that will be the directory created
+ * in the ftrace directory under /sys/kernel/debug/tracing/events/<system>
+ *
+ * The define_trace.h below will also look for a file name of
+ * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here.
+ * In this case, it would look for sample.h
+ *
+ * If the header name will be different than the system name
+ * (as in this case), then you can override the header name that
+ * define_trace.h will look up by defining TRACE_INCLUDE_FILE
+ *
+ * This file is called trace-events-sample.h but we want the system
+ * to be called "sample". Therefore we must define the name of this
+ * file:
+ *
+ * #define TRACE_INCLUDE_FILE trace-events-sample
+ *
+ * As we do an the bottom of this file.
+ *
+ * Notice that TRACE_SYSTEM should be defined outside of #if
+ * protection, just like TRACE_INCLUDE_FILE.
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM sample
+
+/*
+ * Notice that this file is not protected like a normal header.
+ * We also must allow for rereading of this file. The
+ *
+ *  || defined(TRACE_HEADER_MULTI_READ)
+ *
+ * serves this purpose.
+ */
+#if !defined(_TRACE_EVENT_SAMPLE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_EVENT_SAMPLE_H
+
+/*
+ * All trace headers should include tracepoint.h, until we finally
+ * make it into a standard header.
+ */
+#include <linux/tracepoint.h>
+
+/*
+ * The TRACE_EVENT macro is broken up into 5 parts.
+ *
+ * name: name of the trace point. This is also how to enable the tracepoint.
+ *   A function called trace_foo_bar() will be created.
+ *
+ * proto: the prototype of the function trace_foo_bar()
+ *   Here it is trace_foo_bar(char *foo, int bar).
+ *
+ * args:  must match the arguments in the prototype.
+ *    Here it is simply "foo, bar".
+ *
+ * struct:  This defines the way the data will be stored in the ring buffer.
+ *    There are currently two types of elements. __field and __array.
+ *    a __field is broken up into (type, name). Where type can be any
+ *    type but an array.
+ *    For an array. there are three fields. (type, name, size). The
+ *    type of elements in the array, the name of the field and the size
+ *    of the array.
+ *
+ *    __array( char, foo, 10) is the same as saying   char foo[10].
+ *
+ * fast_assign: This is a C like function that is used to store the items
+ *    into the ring buffer.
+ *
+ * printk: This is a way to print out the data in pretty print. This is
+ *    useful if the system crashes and you are logging via a serial line,
+ *    the data can be printed to the console using this "printk" method.
+ *
+ * Note, that for both the assign and the printk, __entry is the handler
+ * to the data structure in the ring buffer, and is defined by the
+ * TP_STRUCT__entry.
+ */
+TRACE_EVENT(foo_bar,
+
+	TP_PROTO(char *foo, int bar),
+
+	TP_ARGS(foo, bar),
+
+	TP_STRUCT__entry(
+		__array(	char,	foo,    10		)
+		__field(	int,	bar			)
+	),
+
+	TP_fast_assign(
+		strncpy(__entry->foo, foo, 10);
+		__entry->bar	= bar;
+	),
+
+	TP_printk("foo %s %d", __entry->foo, __entry->bar)
+);
+#endif
+
+/***** NOTICE! The #if protection ends here. *****/
+
+
+/*
+ * There are several ways I could have done this. If I left out the
+ * TRACE_INCLUDE_PATH, then it would default to the kernel source
+ * include/trace/events directory.
+ *
+ * I could specify a path from the define_trace.h file back to this
+ * file.
+ *
+ * #define TRACE_INCLUDE_PATH ../../samples/trace_events
+ *
+ * But the safest and easiest way to simply make it use the directory
+ * that the file is in is to add in the Makefile:
+ *
+ * CFLAGS_trace-events-sample.o := -I$(src)
+ *
+ * This will make sure the current path is part of the include
+ * structure for our file so that define_trace.h can find it.
+ *
+ * I could have made only the top level directory the include:
+ *
+ * CFLAGS_trace-events-sample.o := -I$(PWD)
+ *
+ * And then let the path to this directory be the TRACE_INCLUDE_PATH:
+ *
+ * #define TRACE_INCLUDE_PATH samples/trace_events
+ *
+ * But then if something defines "samples" or "trace_events" as a macro
+ * then we could risk that being converted too, and give us an unexpected
+ * result.
+ */
+#undef TRACE_INCLUDE_PATH
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_PATH .
+/*
+ * TRACE_INCLUDE_FILE is not needed if the filename and TRACE_SYSTEM are equal
+ */
+#define TRACE_INCLUDE_FILE trace-events-sample
+#include <trace/define_trace.h>
diff --git a/samples/tracepoints/Makefile b/samples/tracepoints/Makefile
new file mode 100644
index 00000000000..36479ad9ae1
--- /dev/null
+++ b/samples/tracepoints/Makefile
@@ -0,0 +1,6 @@
+# builds the tracepoint example kernel modules;
+# then to use one (as root):  insmod <module_name.ko>
+
+obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-sample.o
+obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-probe-sample.o
+obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-probe-sample2.o
diff --git a/samples/tracepoints/tp-samples-trace.h b/samples/tracepoints/tp-samples-trace.h
new file mode 100644
index 00000000000..dffdc49878a
--- /dev/null
+++ b/samples/tracepoints/tp-samples-trace.h
@@ -0,0 +1,13 @@
+#ifndef _TP_SAMPLES_TRACE_H
+#define _TP_SAMPLES_TRACE_H
+
+#include <linux/proc_fs.h>	/* for struct inode and struct file */
+#include <linux/tracepoint.h>
+
+DECLARE_TRACE(subsys_event,
+	TP_PROTO(struct inode *inode, struct file *file),
+	TP_ARGS(inode, file));
+DECLARE_TRACE(subsys_eventb,
+	TP_PROTO(void),
+	TP_ARGS());
+#endif
diff --git a/samples/tracepoints/tracepoint-probe-sample.c b/samples/tracepoints/tracepoint-probe-sample.c
new file mode 100644
index 00000000000..9e60eb6ca2d
--- /dev/null
+++ b/samples/tracepoints/tracepoint-probe-sample.c
@@ -0,0 +1,56 @@
+/*
+ * tracepoint-probe-sample.c
+ *
+ * sample tracepoint probes.
+ */
+
+#include <linux/module.h>
+#include <linux/file.h>
+#include <linux/dcache.h>
+#include "tp-samples-trace.h"
+
+/*
+ * Here the caller only guarantees locking for struct file and struct inode.
+ * Locking must therefore be done in the probe to use the dentry.
+ */
+static void probe_subsys_event(struct inode *inode, struct file *file)
+{
+	path_get(&file->f_path);
+	dget(file->f_path.dentry);
+	printk(KERN_INFO "Event is encountered with filename %s\n",
+		file->f_path.dentry->d_name.name);
+	dput(file->f_path.dentry);
+	path_put(&file->f_path);
+}
+
+static void probe_subsys_eventb(void)
+{
+	printk(KERN_INFO "Event B is encountered\n");
+}
+
+static int __init tp_sample_trace_init(void)
+{
+	int ret;
+
+	ret = register_trace_subsys_event(probe_subsys_event);
+	WARN_ON(ret);
+	ret = register_trace_subsys_eventb(probe_subsys_eventb);
+	WARN_ON(ret);
+
+	return 0;
+}
+
+module_init(tp_sample_trace_init);
+
+static void __exit tp_sample_trace_exit(void)
+{
+	unregister_trace_subsys_eventb(probe_subsys_eventb);
+	unregister_trace_subsys_event(probe_subsys_event);
+	tracepoint_synchronize_unregister();
+}
+
+module_exit(tp_sample_trace_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mathieu Desnoyers");
+MODULE_DESCRIPTION("Tracepoint Probes Samples");
diff --git a/samples/tracepoints/tracepoint-probe-sample2.c b/samples/tracepoints/tracepoint-probe-sample2.c
new file mode 100644
index 00000000000..be2a960573f
--- /dev/null
+++ b/samples/tracepoints/tracepoint-probe-sample2.c
@@ -0,0 +1,43 @@
+/*
+ * tracepoint-probe-sample2.c
+ *
+ * 2nd sample tracepoint probes.
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include "tp-samples-trace.h"
+
+/*
+ * Here the caller only guarantees locking for struct file and struct inode.
+ * Locking must therefore be done in the probe to use the dentry.
+ */
+static void probe_subsys_event(struct inode *inode, struct file *file)
+{
+	printk(KERN_INFO "Event is encountered with inode number %lu\n",
+		inode->i_ino);
+}
+
+static int __init tp_sample_trace_init(void)
+{
+	int ret;
+
+	ret = register_trace_subsys_event(probe_subsys_event);
+	WARN_ON(ret);
+
+	return 0;
+}
+
+module_init(tp_sample_trace_init);
+
+static void __exit tp_sample_trace_exit(void)
+{
+	unregister_trace_subsys_event(probe_subsys_event);
+	tracepoint_synchronize_unregister();
+}
+
+module_exit(tp_sample_trace_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mathieu Desnoyers");
+MODULE_DESCRIPTION("Tracepoint Probes Samples");
diff --git a/samples/tracepoints/tracepoint-sample.c b/samples/tracepoints/tracepoint-sample.c
new file mode 100644
index 00000000000..26fab33ffa8
--- /dev/null
+++ b/samples/tracepoints/tracepoint-sample.c
@@ -0,0 +1,56 @@
+/* tracepoint-sample.c
+ *
+ * Executes a tracepoint when /proc/tracepoint-sample is opened.
+ *
+ * (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/proc_fs.h>
+#include "tp-samples-trace.h"
+
+DEFINE_TRACE(subsys_event);
+DEFINE_TRACE(subsys_eventb);
+
+struct proc_dir_entry *pentry_sample;
+
+static int my_open(struct inode *inode, struct file *file)
+{
+	int i;
+
+	trace_subsys_event(inode, file);
+	for (i = 0; i < 10; i++)
+		trace_subsys_eventb();
+	return -EPERM;
+}
+
+static const struct file_operations mark_ops = {
+	.open = my_open,
+};
+
+static int __init sample_init(void)
+{
+	printk(KERN_ALERT "sample init\n");
+	pentry_sample = proc_create("tracepoint-sample", 0444, NULL,
+		&mark_ops);
+	if (!pentry_sample)
+		return -EPERM;
+	return 0;
+}
+
+static void __exit sample_exit(void)
+{
+	printk(KERN_ALERT "sample exit\n");
+	remove_proc_entry("tracepoint-sample", NULL);
+}
+
+module_init(sample_init)
+module_exit(sample_exit)
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mathieu Desnoyers");
+MODULE_DESCRIPTION("Tracepoint sample");