1 files changed, 581 insertions, 0 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
new file mode 100644
index 000000000000..1880a6438097
--- /dev/null
+++ b/kernel/trace/trace_events.c
@@ -0,0 +1,581 @@
+/*
+ * event tracer
+ *
+ * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
+ *
+ *  - Added format output of fields of the trace point.
+ *    This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
+ *
+ */
+
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/ctype.h>
+
+#include "trace_output.h"
+
+#define TRACE_SYSTEM "TRACE_SYSTEM"
+
+static DEFINE_MUTEX(event_mutex);
+
+#define events_for_each(event)                                          \
+        for (event = __start_ftrace_events;                             \
+             (unsigned long)event < (unsigned long)__stop_ftrace_events; \
+             event++)
+
+void event_trace_printk(unsigned long ip, const char *fmt, ...)
+{
+        va_list ap;
+
+        va_start(ap, fmt);
+        tracing_record_cmdline(current);
+        trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
+        va_end(ap);
+}
+
+static void ftrace_clear_events(void)
+{
+        struct ftrace_event_call *call = (void *)__start_ftrace_events;
+
+
+        while ((unsigned long)call < (unsigned long)__stop_ftrace_events) {
+
+                if (call->enabled) {
+                        call->enabled = 0;
+                        call->unregfunc();
+                }
+                call++;
+        }
+}
+
+static void ftrace_event_enable_disable(struct ftrace_event_call *call,
+                                        int enable)
+{
+
+        switch (enable) {
+        case 0:
+                if (call->enabled) {
+                        call->enabled = 0;
+                        call->unregfunc();
+                }
+                break;
+        case 1:
+                if (!call->enabled) {
+                        call->enabled = 1;
+                        call->regfunc();
+                }
+                break;
+        }
+}
+
+static int ftrace_set_clr_event(char *buf, int set)
+{
+        struct ftrace_event_call *call = __start_ftrace_events;
+        char *event = NULL, *sub = NULL, *match;
+        int ret = -EINVAL;
+
+        /*
+         * The buf format can be <subsystem>:<event-name>
+         *  *:<event-name> means any event by that name.
+         *  :<event-name> is the same.
+         *
+         *  <subsystem>:* means all events in that subsystem
+         *  <subsystem>: means the same.
+         *
+         *  <name> (no ':') means all events in a subsystem with
+         *  the name <name> or any event that matches <name>
+         */
+
+        match = strsep(&buf, ":");
+        if (buf) {
+                sub = match;
+                event = buf;
+                match = NULL;
+
+                if (!strlen(sub) || strcmp(sub, "*") == 0)
+                        sub = NULL;
+                if (!strlen(event) || strcmp(event, "*") == 0)
+                        event = NULL;
+        }
+
+        mutex_lock(&event_mutex);
+        events_for_each(call) {
+
+                if (!call->name)
+                        continue;
+
+                if (match &&
+                    strcmp(match, call->name) != 0 &&
+                    strcmp(match, call->system) != 0)
+                        continue;
+
+                if (sub && strcmp(sub, call->system) != 0)
+                        continue;
+
+                if (event && strcmp(event, call->name) != 0)
+                        continue;
+
+                ftrace_event_enable_disable(call, set);
+
+                ret = 0;
+        }
+        mutex_unlock(&event_mutex);
+
+        return ret;
+}
+
+/* 128 should be much more than enough */
+#define EVENT_BUF_SIZE          127
+
+static ssize_t
+ftrace_event_write(struct file *file, const char __user *ubuf,
+                   size_t cnt, loff_t *ppos)
+{
+        size_t read = 0;
+        int i, set = 1;
+        ssize_t ret;
+        char *buf;
+        char ch;
+
+        if (!cnt || cnt < 0)
+                return 0;
+
+        ret = get_user(ch, ubuf++);
+        if (ret)
+                return ret;
+        read++;
+        cnt--;
+
+        /* skip white space */
+        while (cnt && isspace(ch)) {
+                ret = get_user(ch, ubuf++);
+                if (ret)
+                        return ret;
+                read++;
+                cnt--;
+        }
+
+        /* Only white space found? */
+        if (isspace(ch)) {
+                file->f_pos += read;
+                ret = read;
+                return ret;
+        }
+
+        buf = kmalloc(EVENT_BUF_SIZE+1, GFP_KERNEL);
+        if (!buf)
+                return -ENOMEM;
+
+        if (cnt > EVENT_BUF_SIZE)
+                cnt = EVENT_BUF_SIZE;
+
+        i = 0;
+        while (cnt && !isspace(ch)) {
+                if (!i && ch == '!')
+                        set = 0;
+                else
+                        buf[i++] = ch;
+
+                ret = get_user(ch, ubuf++);
+                if (ret)
+                        goto out_free;
+                read++;
+                cnt--;
+        }
+        buf[i] = 0;
+
+        file->f_pos += read;
+
+        ret = ftrace_set_clr_event(buf, set);
+        if (ret)
+                goto out_free;
+
+        ret = read;
+
+ out_free:
+        kfree(buf);
+
+        return ret;
+}
+
+static void *
+t_next(struct seq_file *m, void *v, loff_t *pos)
+{
+        struct ftrace_event_call *call = m->private;
+        struct ftrace_event_call *next = call;
+
+        (*pos)++;
+
+        if ((unsigned long)call >= (unsigned long)__stop_ftrace_events)
+                return NULL;
+
+        m->private = ++next;
+
+        return call;
+}
+
+static void *t_start(struct seq_file *m, loff_t *pos)
+{
+        return t_next(m, NULL, pos);
+}
+
+static void *
+s_next(struct seq_file *m, void *v, loff_t *pos)
+{
+        struct ftrace_event_call *call = m->private;
+        struct ftrace_event_call *next;
+
+        (*pos)++;
+
+ retry:
+        if ((unsigned long)call >= (unsigned long)__stop_ftrace_events)
+                return NULL;
+
+        if (!call->enabled) {
+                call++;
+                goto retry;
+        }
+
+        next = call;
+        m->private = ++next;
+
+        return call;
+}
+
+static void *s_start(struct seq_file *m, loff_t *pos)
+{
+        return s_next(m, NULL, pos);
+}
+
+static int t_show(struct seq_file *m, void *v)
+{
+        struct ftrace_event_call *call = v;
+
+        if (strcmp(call->system, TRACE_SYSTEM) != 0)
+                seq_printf(m, "%s:", call->system);
+        seq_printf(m, "%s\n", call->name);
+
+        return 0;
+}
+
+static void t_stop(struct seq_file *m, void *p)
+{
+}
+
+static int
+ftrace_event_seq_open(struct inode *inode, struct file *file)
+{
+        int ret;
+        const struct seq_operations *seq_ops;
+
+        if ((file->f_mode & FMODE_WRITE) &&
+            !(file->f_flags & O_APPEND))
+                ftrace_clear_events();
+
+        seq_ops = inode->i_private;
+        ret = seq_open(file, seq_ops);
+        if (!ret) {
+                struct seq_file *m = file->private_data;
+
+                m->private = __start_ftrace_events;
+        }
+        return ret;
+}
+
+static ssize_t
+event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
+                  loff_t *ppos)
+{
+        struct ftrace_event_call *call = filp->private_data;
+        char *buf;
+
+        if (call->enabled)
+                buf = "1\n";
+        else
+                buf = "0\n";
+
+        return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
+}
+
+static ssize_t
+event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
+                   loff_t *ppos)
+{
+        struct ftrace_event_call *call = filp->private_data;
+        char buf[64];
+        unsigned long val;
+        int ret;
+
+        if (cnt >= sizeof(buf))
+                return -EINVAL;
+
+        if (copy_from_user(&buf, ubuf, cnt))
+                return -EFAULT;
+
+        buf[cnt] = 0;
+
+        ret = strict_strtoul(buf, 10, &val);
+        if (ret < 0)
+                return ret;
+
+        switch (val) {
+        case 0:
+        case 1:
+                mutex_lock(&event_mutex);
+                ftrace_event_enable_disable(call, val);
+                mutex_unlock(&event_mutex);
+                break;
+
+        default:
+                return -EINVAL;
+        }
+
+        *ppos += cnt;
+
+        return cnt;
+}
+
+#undef FIELD
+#define FIELD(type, name)                                               \
+        #type, #name, (unsigned int)offsetof(typeof(field), name),      \
+                (unsigned int)sizeof(field.name)
+
+static int trace_write_header(struct trace_seq *s)
+{
+        struct trace_entry field;
+
+        /* struct trace_entry */
+        return trace_seq_printf(s,
+                                "\tfield:%s %s;\toffset:%u;\tsize:%u;\n"
+                                "\tfield:%s %s;\toffset:%u;\tsize:%u;\n"
+                                "\tfield:%s %s;\toffset:%u;\tsize:%u;\n"
+                                "\tfield:%s %s;\toffset:%u;\tsize:%u;\n"
+                                "\tfield:%s %s;\toffset:%u;\tsize:%u;\n"
+                                "\n",
+                                FIELD(unsigned char, type),
+                                FIELD(unsigned char, flags),
+                                FIELD(unsigned char, preempt_count),
+                                FIELD(int, pid),
+                                FIELD(int, tgid));
+}
+
+static ssize_t
+event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
+                  loff_t *ppos)
+{
+        struct ftrace_event_call *call = filp->private_data;
+        struct trace_seq *s;
+        char *buf;
+        int r;
+
+        s = kmalloc(sizeof(*s), GFP_KERNEL);
+        if (!s)
+                return -ENOMEM;
+
+        trace_seq_init(s);
+
+        if (*ppos)
+                return 0;
+
+        /* If any of the first writes fail, so will the show_format. */
+
+        trace_seq_printf(s, "name: %s\n", call->name);
+        trace_seq_printf(s, "ID: %d\n", call->id);
+        trace_seq_printf(s, "format:\n");
+        trace_write_header(s);
+
+        r = call->show_format(s);
+        if (!r) {
+                /*
+                 * ug!  The format output is bigger than a PAGE!!
+                 */
+                buf = "FORMAT TOO BIG\n";
+                r = simple_read_from_buffer(ubuf, cnt, ppos,
+                                              buf, strlen(buf));
+                goto out;
+        }
+
+        r = simple_read_from_buffer(ubuf, cnt, ppos,
+                                    s->buffer, s->len);
+ out:
+        kfree(s);
+        return r;
+}
+
+static const struct seq_operations show_event_seq_ops = {
+        .start = t_start,
+        .next = t_next,
+        .show = t_show,
+        .stop = t_stop,
+};
+
+static const struct seq_operations show_set_event_seq_ops = {
+        .start = s_start,
+        .next = s_next,
+        .show = t_show,
+        .stop = t_stop,
+};
+
+static const struct file_operations ftrace_set_event_fops = {
+        .open = ftrace_event_seq_open,
+        .read = seq_read,
+        .write = ftrace_event_write,
+        .llseek = seq_lseek,
+        .release = seq_release,
+};
+
+static const struct file_operations ftrace_enable_fops = {
+        .open = tracing_open_generic,
+        .read = event_enable_read,
+        .write = event_enable_write,
+};
+
+static const struct file_operations ftrace_event_format_fops = {
+        .open = tracing_open_generic,
+        .read = event_format_read,
+};
+
+static struct dentry *event_trace_events_dir(void)
+{
+        static struct dentry *d_tracer;
+        static struct dentry *d_events;
+
+        if (d_events)
+                return d_events;
+
+        d_tracer = tracing_init_dentry();
+        if (!d_tracer)
+                return NULL;
+
+        d_events = debugfs_create_dir("events", d_tracer);
+        if (!d_events)
+                pr_warning("Could not create debugfs "
+                           "'events' directory\n");
+
+        return d_events;
+}
+
+struct event_subsystem {
+        struct list_head        list;
+        const char              *name;
+        struct dentry           *entry;
+};
+
+static LIST_HEAD(event_subsystems);
+
+static struct dentry *
+event_subsystem_dir(const char *name, struct dentry *d_events)
+{
+        struct event_subsystem *system;
+
+        /* First see if we did not already create this dir */
+        list_for_each_entry(system, &event_subsystems, list) {
+                if (strcmp(system->name, name) == 0)
+                        return system->entry;
+        }
+
+        /* need to create new entry */
+        system = kmalloc(sizeof(*system), GFP_KERNEL);
+        if (!system) {
+                pr_warning("No memory to create event subsystem %s\n",
+                           name);
+                return d_events;
+        }
+
+        system->entry = debugfs_create_dir(name, d_events);
+        if (!system->entry) {
+                pr_warning("Could not create event subsystem %s\n",
+                           name);
+                kfree(system);
+                return d_events;
+        }
+
+        system->name = name;
+        list_add(&system->list, &event_subsystems);
+
+        return system->entry;
+}
+
+static int
+event_create_dir(struct ftrace_event_call *call, struct dentry *d_events)
+{
+        struct dentry *entry;
+        int ret;
+
+        /*
+         * If the trace point header did not define TRACE_SYSTEM
+         * then the system would be called "TRACE_SYSTEM".
+         */
+        if (strcmp(call->system, "TRACE_SYSTEM") != 0)
+                d_events = event_subsystem_dir(call->system, d_events);
+
+        if (call->raw_init) {
+                ret = call->raw_init();
+                if (ret < 0) {
+                        pr_warning("Could not initialize trace point"
+                                   " events/%s\n", call->name);
+                        return ret;
+                }
+        }
+
+        call->dir = debugfs_create_dir(call->name, d_events);
+        if (!call->dir) {
+                pr_warning("Could not create debugfs "
+                           "'%s' directory\n", call->name);
+                return -1;
+        }
+
+        if (call->regfunc) {
+                entry = debugfs_create_file("enable", 0644, call->dir, call,
+                                            &ftrace_enable_fops);
+                if (!entry)
+                        pr_warning("Could not create debugfs "
+                                   "'%s/enable' entry\n", call->name);
+        }
+
+        /* A trace may not want to export its format */
+        if (!call->show_format)
+                return 0;
+
+        entry = debugfs_create_file("format", 0444, call->dir, call,
+                                    &ftrace_event_format_fops);
+        if (!entry)
+                pr_warning("Could not create debugfs "
+                           "'%s/format' entry\n", call->name);
+
+        return 0;
+}
+
+static __init int event_trace_init(void)
+{
+        struct ftrace_event_call *call = __start_ftrace_events;
+        struct dentry *d_tracer;
+        struct dentry *entry;
+        struct dentry *d_events;
+
+        d_tracer = tracing_init_dentry();
+        if (!d_tracer)
+                return 0;
+
+        entry = debugfs_create_file("set_event", 0644, d_tracer,
+                                    (void *)&show_set_event_seq_ops,
+                                    &ftrace_set_event_fops);
+        if (!entry)
+                pr_warning("Could not create debugfs "
+                           "'set_event' entry\n");
+
+        d_events = event_trace_events_dir();
+        if (!d_events)
+                return 0;
+
+        events_for_each(call) {
+                /* The linker may leave blanks */
+                if (!call->name)
+                        continue;
+                event_create_dir(call, d_events);
+        }
+
+        return 0;
+}
+fs_initcall(event_trace_init);