1 files changed, 353 insertions, 16 deletions

diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 9236d7e25a16..c9a0b7df44ff 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -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>
@@ -16,52 +17,388 @@
 
 #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, resched;
+        int pc;
+
+        if (unlikely(!ftrace_function_enabled))
+                return;
+
+        pc = preempt_count();
+        resched = ftrace_preempt_disable();
+        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);
+        ftrace_preempt_enable(resched);
+}
+
+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,
+};
+
+static struct ftrace_ops trace_stack_ops __read_mostly =
+{
+        .func = function_stack_trace_call,
+};
+
+/* 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;
+        /* OK if they are not registered */
+        unregister_ftrace_function(&trace_stack_ops);
+        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)
+{
+        char str[KSYM_SYMBOL_LEN];
+        long count = (long)data;
+
+        kallsyms_lookup(ip, NULL, NULL, NULL, str);
+        seq_printf(m, "%s:", str);
+
+        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", count);
+        seq_putc(m, '\n');
+
+        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(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;
+}
+
+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);
+