tracing: Ftrace dynamic ftrace_event_call support

Add dynamic ftrace_event_call support to ftrace. Trace engines can add
new ftrace_event_call to ftrace on the fly. Each operator function of
the call takes an ftrace_event_call data structure as an argument,
because these functions may be shared among several ftrace_event_calls.

Changes from v13:
 - Define remove_subsystem_dir() always (revirt a2ca5e03), because
   trace_remove_event_call() uses it.
 - Modify syscall tracer because of ftrace_event_call change.

[fweisbec@gmail.com: Fixed conflict against latest tracing/core]

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it>
Cc: Roland McGrath <roland@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
LKML-Reference: <20090813203453.31965.71901.stgit@localhost.localdomain>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index ace2da9..1ab3089 100644 (file)
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -112,12 +112,12 @@ struct ftrace_event_call {
        struct dentry           *dir;
        struct trace_event      *event;
        int                     enabled;
-       int                     (*regfunc)(void *);
-       void                    (*unregfunc)(void *);
+       int                     (*regfunc)(struct ftrace_event_call *);
+       void                    (*unregfunc)(struct ftrace_event_call *);
        int                     id;
-       int                     (*raw_init)(void);
-       int                     (*show_format)(struct ftrace_event_call *call,
-                                              struct trace_seq *s);
+       int                     (*raw_init)(struct ftrace_event_call *);
+       int                     (*show_format)(struct ftrace_event_call *,
+                                              struct trace_seq *);
        int                     (*define_fields)(struct ftrace_event_call *);
        struct list_head        fields;
        int                     filter_active;
@@ -147,11 +147,12 @@ enum {
        FILTER_PTR_STRING,
 };
 
-extern int trace_define_field(struct ftrace_event_call *call,
-                             const char *type, const char *name,
-                             int offset, int size, int is_signed,
-                             int filter_type);
 extern int trace_define_common_fields(struct ftrace_event_call *call);
+extern int trace_define_field(struct ftrace_event_call *call, char *type,
+                             char *name, int offset, int size, int is_signed,
+                             int filter_type);
+extern int trace_add_event_call(struct ftrace_event_call *call);
+extern void trace_remove_event_call(struct ftrace_event_call *call);
 
 #define is_signed_type(type)   (((type)(-1)) < 0)
 

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index f124c89..646102e 100644 (file)
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -165,7 +165,7 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *event_call) \
        struct trace_event enter_syscall_print_##sname = {              \
                .trace                  = print_syscall_enter,          \
        };                                                              \
-       static int init_enter_##sname(void)                             \
+       static int init_enter_##sname(struct ftrace_event_call *call)   \
        {                                                               \
                int num, id;                                            \
                num = syscall_name_to_nr("sys"#sname);                  \
@@ -202,7 +202,7 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *event_call) \
        struct trace_event exit_syscall_print_##sname = {               \
                .trace                  = print_syscall_exit,           \
        };                                                              \
-       static int init_exit_##sname(void)                              \
+       static int init_exit_##sname(struct ftrace_event_call *call)    \
        {                                                               \
                int num, id;                                            \
                num = syscall_name_to_nr("sys"#sname);                  \

diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 360a77a..f2bd7a8 100644 (file)
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -434,7 +434,7 @@ static void ftrace_profile_disable_##call(struct ftrace_event_call *event_call)\
  *     event_trace_printk(_RET_IP_, "<call>: " <fmt>);
  * }
  *
- * static int ftrace_reg_event_<call>(void)
+ * static int ftrace_reg_event_<call>(struct ftrace_event_call *unused)
  * {
  *     int ret;
  *
@@ -445,7 +445,7 @@ static void ftrace_profile_disable_##call(struct ftrace_event_call *event_call)\
  *     return ret;
  * }
  *
- * static void ftrace_unreg_event_<call>(void)
+ * static void ftrace_unreg_event_<call>(struct ftrace_event_call *unused)
  * {
  *     unregister_trace_<call>(ftrace_event_<call>);
  * }
@@ -478,7 +478,7 @@ static void ftrace_profile_disable_##call(struct ftrace_event_call *event_call)\
  *     trace_current_buffer_unlock_commit(event, irq_flags, pc);
  * }
  *
- * static int ftrace_raw_reg_event_<call>(void)
+ * static int ftrace_raw_reg_event_<call>(struct ftrace_event_call *unused)
  * {
  *     int ret;
  *
@@ -489,7 +489,7 @@ static void ftrace_profile_disable_##call(struct ftrace_event_call *event_call)\
  *     return ret;
  * }
  *
- * static void ftrace_unreg_event_<call>(void)
+ * static void ftrace_unreg_event_<call>(struct ftrace_event_call *unused)
  * {
  *     unregister_trace_<call>(ftrace_raw_event_<call>);
  * }
@@ -498,7 +498,7 @@ static void ftrace_profile_disable_##call(struct ftrace_event_call *event_call)\
  *     .trace                  = ftrace_raw_output_<call>, <-- stage 2
  * };
  *
- * static int ftrace_raw_init_event_<call>(void)
+ * static int ftrace_raw_init_event_<call>(struct ftrace_event_call *unused)
  * {
  *     int id;
  *
@@ -592,7 +592,7 @@ static void ftrace_raw_event_##call(proto)                          \
                trace_nowake_buffer_unlock_commit(event, irq_flags, pc); \
 }                                                                      \
                                                                        \
-static int ftrace_raw_reg_event_##call(void *ptr)                      \
+static int ftrace_raw_reg_event_##call(struct ftrace_event_call *unused)\
 {                                                                      \
        int ret;                                                        \
                                                                        \
@@ -603,7 +603,7 @@ static int ftrace_raw_reg_event_##call(void *ptr)                   \
        return ret;                                                     \
 }                                                                      \
                                                                        \
-static void ftrace_raw_unreg_event_##call(void *ptr)                   \
+static void ftrace_raw_unreg_event_##call(struct ftrace_event_call *unused)\
 {                                                                      \
        unregister_trace_##call(ftrace_raw_event_##call);               \
 }                                                                      \
@@ -612,7 +612,7 @@ static struct trace_event ftrace_event_type_##call = {                      \
        .trace                  = ftrace_raw_output_##call,             \
 };                                                                     \
                                                                        \
-static int ftrace_raw_init_event_##call(void)                          \
+static int ftrace_raw_init_event_##call(struct ftrace_event_call *unused)\
 {                                                                      \
        int id;                                                         \
                                                                        \

diff --git a/include/trace/syscall.h b/include/trace/syscall.h
index 5dc283b..e290b86 100644 (file)
--- a/include/trace/syscall.h
+++ b/include/trace/syscall.h
@@ -39,16 +39,19 @@ void set_syscall_enter_id(int num, int id);
 void set_syscall_exit_id(int num, int id);
 extern struct trace_event event_syscall_enter;
 extern struct trace_event event_syscall_exit;
-extern int reg_event_syscall_enter(void *ptr);
-extern void unreg_event_syscall_enter(void *ptr);
-extern int reg_event_syscall_exit(void *ptr);
-extern void unreg_event_syscall_exit(void *ptr);
+
 extern int syscall_enter_format(struct ftrace_event_call *call,
                                struct trace_seq *s);
 extern int syscall_exit_format(struct ftrace_event_call *call,
                                struct trace_seq *s);
 extern int syscall_enter_define_fields(struct ftrace_event_call *call);
 extern int syscall_exit_define_fields(struct ftrace_event_call *call);
+extern int reg_event_syscall_enter(struct ftrace_event_call *call);
+extern void unreg_event_syscall_enter(struct ftrace_event_call *call);
+extern int reg_event_syscall_exit(struct ftrace_event_call *call);
+extern void unreg_event_syscall_exit(struct ftrace_event_call *call);
+extern int
+ftrace_format_syscall(struct ftrace_event_call *call, struct trace_seq *s);
 enum print_line_t print_syscall_enter(struct trace_iterator *iter, int flags);
 enum print_line_t print_syscall_exit(struct trace_iterator *iter, int flags);
 #endif

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index d33bcde..8079bb5 100644 (file)
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -27,8 +27,8 @@ DEFINE_MUTEX(event_mutex);
 
 LIST_HEAD(ftrace_events);
 
-int trace_define_field(struct ftrace_event_call *call, const char *type,
-                      const char *name, int offset, int size, int is_signed,
+int trace_define_field(struct ftrace_event_call *call, char *type,
+                      char *name, int offset, int size, int is_signed,
                       int filter_type)
 {
        struct ftrace_event_field *field;
@@ -92,9 +92,7 @@ int trace_define_common_fields(struct ftrace_event_call *call)
 }
 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;
 
@@ -106,8 +104,6 @@ static void trace_destroy_fields(struct ftrace_event_call *call)
        }
 }
 
-#endif /* CONFIG_MODULES */
-
 static void ftrace_event_enable_disable(struct ftrace_event_call *call,
                                        int enable)
 {
@@ -116,14 +112,14 @@ static void ftrace_event_enable_disable(struct ftrace_event_call *call,
                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);
+                       call->regfunc(call);
                }
                break;
        }
@@ -991,27 +987,43 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
        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;
+
+       list_add(&call->list, &ftrace_events);
+       return event_create_dir(call, d_events, &ftrace_event_id_fops,
+                               &ftrace_enable_fops, &ftrace_event_filter_fops,
+                               &ftrace_event_format_fops);
+}
+
+/* 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)
 {
@@ -1039,6 +1051,48 @@ static void remove_subsystem_dir(const char *name)
        }
 }
 
+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);
+       __trace_remove_event_call(call);
+       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)
 {
@@ -1096,7 +1150,7 @@ 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 "
@@ -1131,14 +1185,7 @@ 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);
                }
        }
 
@@ -1256,7 +1303,7 @@ 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 "

diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index 029a91f..9cbe7f1 100644 (file)
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -117,10 +117,16 @@ ftrace_format_##call(struct ftrace_event_call *unused,                    \
 #define TRACE_FIELD_SPECIAL(type_item, item, len, cmd) \
        cmd;
 
+static int ftrace_raw_init_event(struct ftrace_event_call *event_call)
+{
+       INIT_LIST_HEAD(&event_call->fields);
+       init_preds(event_call);
+       return 0;
+}
+
 #undef TRACE_EVENT_FORMAT
 #define TRACE_EVENT_FORMAT(call, proto, args, fmt, tstruct, tpfmt)     \
 int ftrace_define_fields_##call(struct ftrace_event_call *event_call); \
-static int ftrace_raw_init_event_##call(void);                         \
                                                                        \
 struct ftrace_event_call __used                                                \
 __attribute__((__aligned__(4)))                                                \
@@ -128,16 +134,10 @@ __attribute__((section("_ftrace_events"))) event_##call = {               \
        .name                   = #call,                                \
        .id                     = proto,                                \
        .system                 = __stringify(TRACE_SYSTEM),            \
-       .raw_init               = ftrace_raw_init_event_##call,         \
+       .raw_init               = ftrace_raw_init_event,                \
        .show_format            = ftrace_format_##call,                 \
        .define_fields          = ftrace_define_fields_##call,          \
-};                                                                     \
-static int ftrace_raw_init_event_##call(void)                          \
-{                                                                      \
-       INIT_LIST_HEAD(&event_##call.fields);                           \
-       init_preds(&event_##call);                                      \
-       return 0;                                                       \
-}                                                                      \
+};
 
 #undef TRACE_EVENT_FORMAT_NOFILTER
 #define TRACE_EVENT_FORMAT_NOFILTER(call, proto, args, fmt, tstruct,   \

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 85291c4..5931933 100644 (file)
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -193,8 +193,8 @@ int syscall_enter_define_fields(struct ftrace_event_call *call)
                return ret;
 
        for (i = 0; i < meta->nb_args; i++) {
-               ret = trace_define_field(call, meta->types[i],
-                                        meta->args[i], offset,
+               ret = trace_define_field(call, (char *)meta->types[i],
+                                        (char *)meta->args[i], offset,
                                         sizeof(unsigned long), 0,
                                         FILTER_OTHER);
                offset += sizeof(unsigned long);
@@ -277,13 +277,13 @@ void ftrace_syscall_exit(struct pt_regs *regs, long ret)
                trace_current_buffer_unlock_commit(event, 0, 0);
 }
 
-int reg_event_syscall_enter(void *ptr)
+int reg_event_syscall_enter(struct ftrace_event_call *call)
 {
        int ret = 0;
        int num;
        char *name;
 
-       name = (char *)ptr;
+       name = (char *)call->data;
        num = syscall_name_to_nr(name);
        if (num < 0 || num >= FTRACE_SYSCALL_MAX)
                return -ENOSYS;
@@ -301,12 +301,12 @@ int reg_event_syscall_enter(void *ptr)
        return ret;
 }
 
-void unreg_event_syscall_enter(void *ptr)
+void unreg_event_syscall_enter(struct ftrace_event_call *call)
 {
        int num;
        char *name;
 
-       name = (char *)ptr;
+       name = (char *)call->data;
        num = syscall_name_to_nr(name);
        if (num < 0 || num >= FTRACE_SYSCALL_MAX)
                return;
@@ -318,13 +318,13 @@ void unreg_event_syscall_enter(void *ptr)
        mutex_unlock(&syscall_trace_lock);
 }
 
-int reg_event_syscall_exit(void *ptr)
+int reg_event_syscall_exit(struct ftrace_event_call *call)
 {
        int ret = 0;
        int num;
        char *name;
 
-       name = (char *)ptr;
+       name = (char *)call->data;
        num = syscall_name_to_nr(name);
        if (num < 0 || num >= FTRACE_SYSCALL_MAX)
                return -ENOSYS;
@@ -342,12 +342,12 @@ int reg_event_syscall_exit(void *ptr)
        return ret;
 }
 
-void unreg_event_syscall_exit(void *ptr)
+void unreg_event_syscall_exit(struct ftrace_event_call *call)
 {
        int num;
        char *name;
 
-       name = (char *)ptr;
+       name = (char *)call->data;
        num = syscall_name_to_nr(name);
        if (num < 0 || num >= FTRACE_SYSCALL_MAX)
                return;