ftrace: extend sysprof plugin some more

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 76 insertions, 4 deletions

diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c
index ba55b871b3d9..b1137c11ef8b 100644
--- a/kernel/trace/trace_sysprof.c
+++ b/kernel/trace/trace_sysprof.c
@@ -3,7 +3,7 @@
  *
  * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
  * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
- *
+ * Copyright (C) 2004, 2005, Soeren Sandmann
  */
 #include <linux/kallsyms.h>
 #include <linux/debugfs.h>
@@ -11,13 +11,17 @@
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
 #include <linux/module.h>
+#include <linux/irq.h>
 #include <linux/fs.h>
 
 #include "trace.h"
 
-static struct trace_array       *ctx_trace;
+static struct trace_array       *sysprof_trace;
 static int __read_mostly        tracer_enabled;
 
+/*
+ * 10 msecs for now:
+ */
 static const unsigned long sample_period = 1000000;
 
 /*
@@ -25,10 +29,78 @@ static const unsigned long sample_period = 1000000;
  */
 static DEFINE_PER_CPU(struct hrtimer, stack_trace_hrtimer);
 
+struct stack_frame {
+        const void __user       *next_fp;
+        unsigned long           return_address;
+};
+
+static int copy_stack_frame(const void __user *fp, struct stack_frame *frame)
+{
+        if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))
+                return 0;
+
+        if (__copy_from_user_inatomic(frame, frame_pointer, sizeof(*frame)))
+                return 0;
+
+        return 1;
+}
+
+#define SYSPROF_MAX_ADDRESSES   512
+
+static void timer_notify(struct pt_regs *regs, int cpu)
+{
+        const void __user *frame_pointer;
+        struct trace_array_cpu *data;
+        struct stack_frame frame;
+        struct trace_array *tr;
+        int is_user;
+        int i;
+
+        if (!regs)
+                return;
+
+        tr = sysprof_trace;
+        data = tr->data[cpu];
+        is_user = user_mode(regs);
+
+        if (!current || current->pid == 0)
+                return;
+
+        if (is_user && current->state != TASK_RUNNING)
+                return;
+
+        if (!is_user) {
+                /* kernel */
+                ftrace(tr, data, current->pid, 1, 0);
+                return;
+
+        }
+
+        trace_special(tr, data, 0, current->pid, regs->ip);
+
+        frame_pointer = (void __user *)regs->bp;
+
+        for (i = 0; i < SYSPROF_MAX_ADDRESSES; i++) {
+                if (!copy_stack_frame(frame_pointer, &frame))
+                        break;
+                if ((unsigned long)frame_pointer < regs->sp)
+                        break;
+
+                trace_special(tr, data, 1, frame.return_address,
+                              (unsigned long)frame_pointer);
+                frame_pointer = frame.next_fp;
+        }
+
+        trace_special(tr, data, 2, current->pid, i);
+
+        if (i == SYSPROF_MAX_ADDRESSES)
+                trace_special(tr, data, -1, -1, -1);
+}
+
 static enum hrtimer_restart stack_trace_timer_fn(struct hrtimer *hrtimer)
 {
         /* trace here */
-        panic_timeout++;
+        timer_notify(get_irq_regs(), smp_processor_id());
 
         hrtimer_forward_now(hrtimer, ns_to_ktime(sample_period));
 
@@ -100,7 +172,7 @@ static notrace void stop_stack_trace(struct trace_array *tr)
 
 static notrace void stack_trace_init(struct trace_array *tr)
 {
-        ctx_trace = tr;
+        sysprof_trace = tr;
 
         if (tr->ctrl)
                 start_stack_trace(tr);