ftrace: Fix regression of :mod:module function enabling
[linux-2.6.git] / kernel / trace / trace_functions.c
index 9236d7e..c7b0c6a 100644 (file)
@@ -9,6 +9,7 @@
  *  Copyright (C) 2004-2006 Ingo Molnar
  *  Copyright (C) 2004 William Lee Irwin III
  */
+#include <linux/ring_buffer.h>
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
 
 #include "trace.h"
 
-static void start_function_trace(struct trace_array *tr)
+/* function tracing enabled */
+static int                     ftrace_function_enabled;
+
+static struct trace_array      *func_trace;
+
+static void tracing_start_function_trace(void);
+static void tracing_stop_function_trace(void);
+
+static int function_trace_init(struct trace_array *tr)
 {
+       func_trace = tr;
        tr->cpu = get_cpu();
-       tracing_reset_online_cpus(tr);
        put_cpu();
 
        tracing_start_cmdline_record();
        tracing_start_function_trace();
+       return 0;
 }
 
-static void stop_function_trace(struct trace_array *tr)
+static void function_trace_reset(struct trace_array *tr)
 {
        tracing_stop_function_trace();
        tracing_stop_cmdline_record();
 }
 
-static int function_trace_init(struct trace_array *tr)
+static void function_trace_start(struct trace_array *tr)
 {
-       start_function_trace(tr);
-       return 0;
+       tracing_reset_online_cpus(tr);
 }
 
-static void function_trace_reset(struct trace_array *tr)
+static void
+function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip)
+{
+       struct trace_array *tr = func_trace;
+       struct trace_array_cpu *data;
+       unsigned long flags;
+       long disabled;
+       int cpu;
+       int pc;
+
+       if (unlikely(!ftrace_function_enabled))
+               return;
+
+       pc = preempt_count();
+       preempt_disable_notrace();
+       local_save_flags(flags);
+       cpu = raw_smp_processor_id();
+       data = tr->data[cpu];
+       disabled = atomic_inc_return(&data->disabled);
+
+       if (likely(disabled == 1))
+               trace_function(tr, ip, parent_ip, flags, pc);
+
+       atomic_dec(&data->disabled);
+       preempt_enable_notrace();
+}
+
+static void
+function_trace_call(unsigned long ip, unsigned long parent_ip)
 {
-       stop_function_trace(tr);
+       struct trace_array *tr = func_trace;
+       struct trace_array_cpu *data;
+       unsigned long flags;
+       long disabled;
+       int cpu;
+       int pc;
+
+       if (unlikely(!ftrace_function_enabled))
+               return;
+
+       /*
+        * Need to use raw, since this must be called before the
+        * recursive protection is performed.
+        */
+       local_irq_save(flags);
+       cpu = raw_smp_processor_id();
+       data = tr->data[cpu];
+       disabled = atomic_inc_return(&data->disabled);
+
+       if (likely(disabled == 1)) {
+               pc = preempt_count();
+               trace_function(tr, ip, parent_ip, flags, pc);
+       }
+
+       atomic_dec(&data->disabled);
+       local_irq_restore(flags);
 }
 
-static void function_trace_start(struct trace_array *tr)
+static void
+function_stack_trace_call(unsigned long ip, unsigned long parent_ip)
 {
-       tracing_reset_online_cpus(tr);
+       struct trace_array *tr = func_trace;
+       struct trace_array_cpu *data;
+       unsigned long flags;
+       long disabled;
+       int cpu;
+       int pc;
+
+       if (unlikely(!ftrace_function_enabled))
+               return;
+
+       /*
+        * Need to use raw, since this must be called before the
+        * recursive protection is performed.
+        */
+       local_irq_save(flags);
+       cpu = raw_smp_processor_id();
+       data = tr->data[cpu];
+       disabled = atomic_inc_return(&data->disabled);
+
+       if (likely(disabled == 1)) {
+               pc = preempt_count();
+               trace_function(tr, ip, parent_ip, flags, pc);
+               /*
+                * skip over 5 funcs:
+                *    __ftrace_trace_stack,
+                *    __trace_stack,
+                *    function_stack_trace_call
+                *    ftrace_list_func
+                *    ftrace_call
+                */
+               __trace_stack(tr, flags, 5, pc);
+       }
+
+       atomic_dec(&data->disabled);
+       local_irq_restore(flags);
+}
+
+
+static struct ftrace_ops trace_ops __read_mostly =
+{
+       .func = function_trace_call,
+       .flags = FTRACE_OPS_FL_GLOBAL,
+};
+
+static struct ftrace_ops trace_stack_ops __read_mostly =
+{
+       .func = function_stack_trace_call,
+       .flags = FTRACE_OPS_FL_GLOBAL,
+};
+
+/* Our two options */
+enum {
+       TRACE_FUNC_OPT_STACK = 0x1,
+};
+
+static struct tracer_opt func_opts[] = {
+#ifdef CONFIG_STACKTRACE
+       { TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) },
+#endif
+       { } /* Always set a last empty entry */
+};
+
+static struct tracer_flags func_flags = {
+       .val = 0, /* By default: all flags disabled */
+       .opts = func_opts
+};
+
+static void tracing_start_function_trace(void)
+{
+       ftrace_function_enabled = 0;
+
+       if (trace_flags & TRACE_ITER_PREEMPTONLY)
+               trace_ops.func = function_trace_call_preempt_only;
+       else
+               trace_ops.func = function_trace_call;
+
+       if (func_flags.val & TRACE_FUNC_OPT_STACK)
+               register_ftrace_function(&trace_stack_ops);
+       else
+               register_ftrace_function(&trace_ops);
+
+       ftrace_function_enabled = 1;
+}
+
+static void tracing_stop_function_trace(void)
+{
+       ftrace_function_enabled = 0;
+
+       if (func_flags.val & TRACE_FUNC_OPT_STACK)
+               unregister_ftrace_function(&trace_stack_ops);
+       else
+               unregister_ftrace_function(&trace_ops);
+}
+
+static int func_set_flag(u32 old_flags, u32 bit, int set)
+{
+       if (bit == TRACE_FUNC_OPT_STACK) {
+               /* do nothing if already set */
+               if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK))
+                       return 0;
+
+               if (set) {
+                       unregister_ftrace_function(&trace_ops);
+                       register_ftrace_function(&trace_stack_ops);
+               } else {
+                       unregister_ftrace_function(&trace_stack_ops);
+                       register_ftrace_function(&trace_ops);
+               }
+
+               return 0;
+       }
+
+       return -EINVAL;
 }
 
 static struct tracer function_trace __read_mostly =
 {
-       .name        = "function",
-       .init        = function_trace_init,
-       .reset       = function_trace_reset,
-       .start       = function_trace_start,
+       .name           = "function",
+       .init           = function_trace_init,
+       .reset          = function_trace_reset,
+       .start          = function_trace_start,
+       .wait_pipe      = poll_wait_pipe,
+       .flags          = &func_flags,
+       .set_flag       = func_set_flag,
 #ifdef CONFIG_FTRACE_SELFTEST
-       .selftest    = trace_selftest_startup_function,
+       .selftest       = trace_selftest_startup_function,
 #endif
 };
 
+#ifdef CONFIG_DYNAMIC_FTRACE
+static void
+ftrace_traceon(unsigned long ip, unsigned long parent_ip, void **data)
+{
+       long *count = (long *)data;
+
+       if (tracing_is_on())
+               return;
+
+       if (!*count)
+               return;
+
+       if (*count != -1)
+               (*count)--;
+
+       tracing_on();
+}
+
+static void
+ftrace_traceoff(unsigned long ip, unsigned long parent_ip, void **data)
+{
+       long *count = (long *)data;
+
+       if (!tracing_is_on())
+               return;
+
+       if (!*count)
+               return;
+
+       if (*count != -1)
+               (*count)--;
+
+       tracing_off();
+}
+
+static int
+ftrace_trace_onoff_print(struct seq_file *m, unsigned long ip,
+                        struct ftrace_probe_ops *ops, void *data);
+
+static struct ftrace_probe_ops traceon_probe_ops = {
+       .func                   = ftrace_traceon,
+       .print                  = ftrace_trace_onoff_print,
+};
+
+static struct ftrace_probe_ops traceoff_probe_ops = {
+       .func                   = ftrace_traceoff,
+       .print                  = ftrace_trace_onoff_print,
+};
+
+static int
+ftrace_trace_onoff_print(struct seq_file *m, unsigned long ip,
+                        struct ftrace_probe_ops *ops, void *data)
+{
+       long count = (long)data;
+
+       seq_printf(m, "%ps:", (void *)ip);
+
+       if (ops == &traceon_probe_ops)
+               seq_printf(m, "traceon");
+       else
+               seq_printf(m, "traceoff");
+
+       if (count == -1)
+               seq_printf(m, ":unlimited\n");
+       else
+               seq_printf(m, ":count=%ld\n", count);
+
+       return 0;
+}
+
+static int
+ftrace_trace_onoff_unreg(char *glob, char *cmd, char *param)
+{
+       struct ftrace_probe_ops *ops;
+
+       /* we register both traceon and traceoff to this callback */
+       if (strcmp(cmd, "traceon") == 0)
+               ops = &traceon_probe_ops;
+       else
+               ops = &traceoff_probe_ops;
+
+       unregister_ftrace_function_probe_func(glob, ops);
+
+       return 0;
+}
+
+static int
+ftrace_trace_onoff_callback(struct ftrace_hash *hash,
+                           char *glob, char *cmd, char *param, int enable)
+{
+       struct ftrace_probe_ops *ops;
+       void *count = (void *)-1;
+       char *number;
+       int ret;
+
+       /* hash funcs only work with set_ftrace_filter */
+       if (!enable)
+               return -EINVAL;
+
+       if (glob[0] == '!')
+               return ftrace_trace_onoff_unreg(glob+1, cmd, param);
+
+       /* we register both traceon and traceoff to this callback */
+       if (strcmp(cmd, "traceon") == 0)
+               ops = &traceon_probe_ops;
+       else
+               ops = &traceoff_probe_ops;
+
+       if (!param)
+               goto out_reg;
+
+       number = strsep(&param, ":");
+
+       if (!strlen(number))
+               goto out_reg;
+
+       /*
+        * We use the callback data field (which is a pointer)
+        * as our counter.
+        */
+       ret = strict_strtoul(number, 0, (unsigned long *)&count);
+       if (ret)
+               return ret;
+
+ out_reg:
+       ret = register_ftrace_function_probe(glob, ops, count);
+
+       return ret < 0 ? ret : 0;
+}
+
+static struct ftrace_func_command ftrace_traceon_cmd = {
+       .name                   = "traceon",
+       .func                   = ftrace_trace_onoff_callback,
+};
+
+static struct ftrace_func_command ftrace_traceoff_cmd = {
+       .name                   = "traceoff",
+       .func                   = ftrace_trace_onoff_callback,
+};
+
+static int __init init_func_cmd_traceon(void)
+{
+       int ret;
+
+       ret = register_ftrace_command(&ftrace_traceoff_cmd);
+       if (ret)
+               return ret;
+
+       ret = register_ftrace_command(&ftrace_traceon_cmd);
+       if (ret)
+               unregister_ftrace_command(&ftrace_traceoff_cmd);
+       return ret;
+}
+#else
+static inline int init_func_cmd_traceon(void)
+{
+       return 0;
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
 static __init int init_function_trace(void)
 {
+       init_func_cmd_traceon();
        return register_tracer(&function_trace);
 }
-
 device_initcall(init_function_trace);
+