kgdb: gdb "monitor" -> kdb passthrough
[safe/jmp/linux-2.6] / kernel / trace / trace_events.c
index 8c91b7c..c697c70 100644 (file)
@@ -15,6 +15,7 @@
 #include <linux/uaccess.h>
 #include <linux/module.h>
 #include <linux/ctype.h>
+#include <linux/slab.h>
 #include <linux/delay.h>
 
 #include <asm/setup.h>
@@ -60,10 +61,8 @@ int trace_define_field(struct ftrace_event_call *call, const char *type,
        return 0;
 
 err:
-       if (field) {
+       if (field)
                kfree(field->name);
-               kfree(field->type);
-       }
        kfree(field);
 
        return -ENOMEM;
@@ -78,7 +77,7 @@ EXPORT_SYMBOL_GPL(trace_define_field);
        if (ret)                                                        \
                return ret;
 
-int trace_define_common_fields(struct ftrace_event_call *call)
+static int trace_define_common_fields(struct ftrace_event_call *call)
 {
        int ret;
        struct trace_entry ent;
@@ -91,11 +90,8 @@ int trace_define_common_fields(struct ftrace_event_call *call)
 
        return ret;
 }
-EXPORT_SYMBOL_GPL(trace_define_common_fields);
 
-#ifdef CONFIG_MODULES
-
-static void trace_destroy_fields(struct ftrace_event_call *call)
+void trace_destroy_fields(struct ftrace_event_call *call)
 {
        struct ftrace_event_field *field, *next;
 
@@ -107,27 +103,49 @@ static void trace_destroy_fields(struct ftrace_event_call *call)
        }
 }
 
-#endif /* CONFIG_MODULES */
+int trace_event_raw_init(struct ftrace_event_call *call)
+{
+       int id;
+
+       id = register_ftrace_event(call->event);
+       if (!id)
+               return -ENODEV;
+       call->id = id;
+       INIT_LIST_HEAD(&call->fields);
 
-static void ftrace_event_enable_disable(struct ftrace_event_call *call,
+       return 0;
+}
+EXPORT_SYMBOL_GPL(trace_event_raw_init);
+
+static int ftrace_event_enable_disable(struct ftrace_event_call *call,
                                        int enable)
 {
+       int ret = 0;
+
        switch (enable) {
        case 0:
                if (call->enabled) {
                        call->enabled = 0;
                        tracing_stop_cmdline_record();
-                       call->unregfunc(call->data);
+                       call->unregfunc(call);
                }
                break;
        case 1:
                if (!call->enabled) {
-                       call->enabled = 1;
                        tracing_start_cmdline_record();
-                       call->regfunc(call->data);
+                       ret = call->regfunc(call);
+                       if (ret) {
+                               tracing_stop_cmdline_record();
+                               pr_info("event trace: Could not enable event "
+                                       "%s\n", call->name);
+                               break;
+                       }
+                       call->enabled = 1;
                }
                break;
        }
+
+       return ret;
 }
 
 static void ftrace_clear_events(void)
@@ -232,10 +250,9 @@ ftrace_event_write(struct file *file, const char __user *ubuf,
                   size_t cnt, loff_t *ppos)
 {
        struct trace_parser parser;
-       size_t read = 0;
-       ssize_t ret;
+       ssize_t read, ret;
 
-       if (!cnt || cnt < 0)
+       if (!cnt)
                return 0;
 
        ret = tracing_update_buffers();
@@ -247,7 +264,7 @@ ftrace_event_write(struct file *file, const char __user *ubuf,
 
        read = trace_get_user(&parser, ubuf, cnt, ppos);
 
-       if (trace_parser_loaded((&parser))) {
+       if (read >= 0 && trace_parser_loaded((&parser))) {
                int set = 1;
 
                if (*parser.buffer == '!')
@@ -271,42 +288,32 @@ ftrace_event_write(struct file *file, const char __user *ubuf,
 static void *
 t_next(struct seq_file *m, void *v, loff_t *pos)
 {
-       struct list_head *list = m->private;
-       struct ftrace_event_call *call;
+       struct ftrace_event_call *call = v;
 
        (*pos)++;
 
-       for (;;) {
-               if (list == &ftrace_events)
-                       return NULL;
-
-               call = list_entry(list, struct ftrace_event_call, list);
-
+       list_for_each_entry_continue(call, &ftrace_events, list) {
                /*
                 * The ftrace subsystem is for showing formats only.
                 * They can not be enabled or disabled via the event files.
                 */
                if (call->regfunc)
-                       break;
-
-               list = list->next;
+                       return call;
        }
 
-       m->private = list->next;
-
-       return call;
+       return NULL;
 }
 
 static void *t_start(struct seq_file *m, loff_t *pos)
 {
-       struct ftrace_event_call *call = NULL;
+       struct ftrace_event_call *call;
        loff_t l;
 
        mutex_lock(&event_mutex);
 
-       m->private = ftrace_events.next;
+       call = list_entry(&ftrace_events, struct ftrace_event_call, list);
        for (l = 0; l <= *pos; ) {
-               call = t_next(m, NULL, &l);
+               call = t_next(m, call, &l);
                if (!call)
                        break;
        }
@@ -316,37 +323,28 @@ static void *t_start(struct seq_file *m, loff_t *pos)
 static void *
 s_next(struct seq_file *m, void *v, loff_t *pos)
 {
-       struct list_head *list = m->private;
-       struct ftrace_event_call *call;
+       struct ftrace_event_call *call = v;
 
        (*pos)++;
 
- retry:
-       if (list == &ftrace_events)
-               return NULL;
-
-       call = list_entry(list, struct ftrace_event_call, list);
-
-       if (!call->enabled) {
-               list = list->next;
-               goto retry;
+       list_for_each_entry_continue(call, &ftrace_events, list) {
+               if (call->enabled)
+                       return call;
        }
 
-       m->private = list->next;
-
-       return call;
+       return NULL;
 }
 
 static void *s_start(struct seq_file *m, loff_t *pos)
 {
-       struct ftrace_event_call *call = NULL;
+       struct ftrace_event_call *call;
        loff_t l;
 
        mutex_lock(&event_mutex);
 
-       m->private = ftrace_events.next;
+       call = list_entry(&ftrace_events, struct ftrace_event_call, list);
        for (l = 0; l <= *pos; ) {
-               call = s_next(m, NULL, &l);
+               call = s_next(m, call, &l);
                if (!call)
                        break;
        }
@@ -426,7 +424,7 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
        case 0:
        case 1:
                mutex_lock(&event_mutex);
-               ftrace_event_enable_disable(call, val);
+               ret = ftrace_event_enable_disable(call, val);
                mutex_unlock(&event_mutex);
                break;
 
@@ -436,7 +434,7 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
 
        *ppos += cnt;
 
-       return cnt;
+       return ret ? ret : cnt;
 }
 
 static ssize_t
@@ -521,41 +519,16 @@ out:
        return ret;
 }
 
-extern char *__bad_type_size(void);
-
-#undef FIELD
-#define FIELD(type, name)                                              \
-       sizeof(type) != sizeof(field.name) ? __bad_type_size() :        \
-       #type, "common_" #name, offsetof(typeof(field), name),          \
-               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:%zu;\tsize:%zu;\n"
-                               "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
-                               "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
-                               "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
-                               "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
-                               "\n",
-                               FIELD(unsigned short, type),
-                               FIELD(unsigned char, flags),
-                               FIELD(unsigned char, preempt_count),
-                               FIELD(int, pid),
-                               FIELD(int, lock_depth));
-}
-
 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 ftrace_event_field *field;
        struct trace_seq *s;
+       int common_field_count = 5;
        char *buf;
-       int r;
+       int r = 0;
 
        if (*ppos)
                return 0;
@@ -566,14 +539,48 @@ event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
 
        trace_seq_init(s);
 
-       /* 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(call, s);
+       list_for_each_entry_reverse(field, &call->fields, link) {
+               /*
+                * Smartly shows the array type(except dynamic array).
+                * Normal:
+                *      field:TYPE VAR
+                * If TYPE := TYPE[LEN], it is shown:
+                *      field:TYPE VAR[LEN]
+                */
+               const char *array_descriptor = strchr(field->type, '[');
+
+               if (!strncmp(field->type, "__data_loc", 10))
+                       array_descriptor = NULL;
+
+               if (!array_descriptor) {
+                       r = trace_seq_printf(s, "\tfield:%s %s;\toffset:%u;"
+                                       "\tsize:%u;\tsigned:%d;\n",
+                                       field->type, field->name, field->offset,
+                                       field->size, !!field->is_signed);
+               } else {
+                       r = trace_seq_printf(s, "\tfield:%.*s %s%s;\toffset:%u;"
+                                       "\tsize:%u;\tsigned:%d;\n",
+                                       (int)(array_descriptor - field->type),
+                                       field->type, field->name,
+                                       array_descriptor, field->offset,
+                                       field->size, !!field->is_signed);
+               }
+
+               if (--common_field_count == 0)
+                       r = trace_seq_printf(s, "\n");
+
+               if (!r)
+                       break;
+       }
+
+       if (r)
+               r = trace_seq_printf(s, "\nprint fmt: %s\n",
+                               call->print_fmt);
+
        if (!r) {
                /*
                 * ug!  The format output is bigger than a PAGE!!
@@ -932,12 +939,14 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
                trace_create_file("enable", 0644, call->dir, call,
                                  enable);
 
-       if (call->id && call->profile_enable)
+       if (call->id && call->perf_event_enable)
                trace_create_file("id", 0444, call->dir, call,
                                  id);
 
        if (call->define_fields) {
-               ret = call->define_fields(call);
+               ret = trace_define_common_fields(call);
+               if (!ret)
+                       ret = call->define_fields(call);
                if (ret < 0) {
                        pr_warning("Could not initialize trace point"
                                   " events/%s\n", call->name);
@@ -947,37 +956,52 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
                                  filter);
        }
 
-       /* A trace may not want to export its format */
-       if (!call->show_format)
-               return 0;
-
        trace_create_file("format", 0444, call->dir, call,
                          format);
 
        return 0;
 }
 
-#define for_each_event(event, start, end)                      \
-       for (event = start;                                     \
-            (unsigned long)event < (unsigned long)end;         \
-            event++)
+static int __trace_add_event_call(struct ftrace_event_call *call)
+{
+       struct dentry *d_events;
+       int ret;
 
-#ifdef CONFIG_MODULES
+       if (!call->name)
+               return -EINVAL;
 
-static LIST_HEAD(ftrace_module_file_list);
+       if (call->raw_init) {
+               ret = call->raw_init(call);
+               if (ret < 0) {
+                       if (ret != -ENOSYS)
+                               pr_warning("Could not initialize trace "
+                               "events/%s\n", call->name);
+                       return ret;
+               }
+       }
 
-/*
- * Modules must own their file_operations to keep up with
- * reference counting.
- */
-struct ftrace_module_file_ops {
-       struct list_head                list;
-       struct module                   *mod;
-       struct file_operations          id;
-       struct file_operations          enable;
-       struct file_operations          format;
-       struct file_operations          filter;
-};
+       d_events = event_trace_events_dir();
+       if (!d_events)
+               return -ENOENT;
+
+       ret = event_create_dir(call, d_events, &ftrace_event_id_fops,
+                               &ftrace_enable_fops, &ftrace_event_filter_fops,
+                               &ftrace_event_format_fops);
+       if (!ret)
+               list_add(&call->list, &ftrace_events);
+
+       return ret;
+}
+
+/* Add an additional event_call dynamically */
+int trace_add_event_call(struct ftrace_event_call *call)
+{
+       int ret;
+       mutex_lock(&event_mutex);
+       ret = __trace_add_event_call(call);
+       mutex_unlock(&event_mutex);
+       return ret;
+}
 
 static void remove_subsystem_dir(const char *name)
 {
@@ -1005,6 +1029,53 @@ static void remove_subsystem_dir(const char *name)
        }
 }
 
+/*
+ * Must be called under locking both of event_mutex and trace_event_mutex.
+ */
+static void __trace_remove_event_call(struct ftrace_event_call *call)
+{
+       ftrace_event_enable_disable(call, 0);
+       if (call->event)
+               __unregister_ftrace_event(call->event);
+       debugfs_remove_recursive(call->dir);
+       list_del(&call->list);
+       trace_destroy_fields(call);
+       destroy_preds(call);
+       remove_subsystem_dir(call->system);
+}
+
+/* Remove an event_call */
+void trace_remove_event_call(struct ftrace_event_call *call)
+{
+       mutex_lock(&event_mutex);
+       down_write(&trace_event_mutex);
+       __trace_remove_event_call(call);
+       up_write(&trace_event_mutex);
+       mutex_unlock(&event_mutex);
+}
+
+#define for_each_event(event, start, end)                      \
+       for (event = start;                                     \
+            (unsigned long)event < (unsigned long)end;         \
+            event++)
+
+#ifdef CONFIG_MODULES
+
+static LIST_HEAD(ftrace_module_file_list);
+
+/*
+ * Modules must own their file_operations to keep up with
+ * reference counting.
+ */
+struct ftrace_module_file_ops {
+       struct list_head                list;
+       struct module                   *mod;
+       struct file_operations          id;
+       struct file_operations          enable;
+       struct file_operations          format;
+       struct file_operations          filter;
+};
+
 static struct ftrace_module_file_ops *
 trace_create_file_ops(struct module *mod)
 {
@@ -1062,7 +1133,7 @@ static void trace_module_add_events(struct module *mod)
                if (!call->name)
                        continue;
                if (call->raw_init) {
-                       ret = call->raw_init();
+                       ret = call->raw_init(call);
                        if (ret < 0) {
                                if (ret != -ENOSYS)
                                        pr_warning("Could not initialize trace "
@@ -1080,10 +1151,11 @@ static void trace_module_add_events(struct module *mod)
                                return;
                }
                call->mod = mod;
-               list_add(&call->list, &ftrace_events);
-               event_create_dir(call, d_events,
-                                &file_ops->id, &file_ops->enable,
-                                &file_ops->filter, &file_ops->format);
+               ret = event_create_dir(call, d_events,
+                                      &file_ops->id, &file_ops->enable,
+                                      &file_ops->filter, &file_ops->format);
+               if (!ret)
+                       list_add(&call->list, &ftrace_events);
        }
 }
 
@@ -1097,14 +1169,7 @@ static void trace_module_remove_events(struct module *mod)
        list_for_each_entry_safe(call, p, &ftrace_events, list) {
                if (call->mod == mod) {
                        found = true;
-                       ftrace_event_enable_disable(call, 0);
-                       if (call->event)
-                               __unregister_ftrace_event(call->event);
-                       debugfs_remove_recursive(call->dir);
-                       list_del(&call->list);
-                       trace_destroy_fields(call);
-                       destroy_preds(call);
-                       remove_subsystem_dir(call->system);
+                       __trace_remove_event_call(call);
                }
        }
 
@@ -1222,7 +1287,7 @@ static __init int event_trace_init(void)
                if (!call->name)
                        continue;
                if (call->raw_init) {
-                       ret = call->raw_init();
+                       ret = call->raw_init(call);
                        if (ret < 0) {
                                if (ret != -ENOSYS)
                                        pr_warning("Could not initialize trace "
@@ -1230,10 +1295,12 @@ static __init int event_trace_init(void)
                                continue;
                        }
                }
-               list_add(&call->list, &ftrace_events);
-               event_create_dir(call, d_events, &ftrace_event_id_fops,
-                                &ftrace_enable_fops, &ftrace_event_filter_fops,
-                                &ftrace_event_format_fops);
+               ret = event_create_dir(call, d_events, &ftrace_event_id_fops,
+                                      &ftrace_enable_fops,
+                                      &ftrace_event_filter_fops,
+                                      &ftrace_event_format_fops);
+               if (!ret)
+                       list_add(&call->list, &ftrace_events);
        }
 
        while (true) {