1 files changed, 482 insertions, 211 deletions

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 930c08e5b38e..420ec3487579 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -1,7 +1,7 @@
 /*
  *
  * Function graph tracer.
- * Copyright (c) 2008 Frederic Weisbecker <fweisbec@gmail.com>
+ * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
  * Mostly borrowed from function tracer which
  * is Copyright (c) Steven Rostedt <srostedt@redhat.com>
  *
@@ -12,6 +12,12 @@
 #include <linux/fs.h>
 
 #include "trace.h"
+#include "trace_output.h"
+
+struct fgraph_data {
+        pid_t           last_pid;
+        int             depth;
+};
 
 #define TRACE_GRAPH_INDENT      2
 
@@ -20,9 +26,11 @@
 #define TRACE_GRAPH_PRINT_CPU           0x2
 #define TRACE_GRAPH_PRINT_OVERHEAD      0x4
 #define TRACE_GRAPH_PRINT_PROC          0x8
+#define TRACE_GRAPH_PRINT_DURATION      0x10
+#define TRACE_GRAPH_PRINT_ABS_TIME      0X20
 
 static struct tracer_opt trace_opts[] = {
-        /* Display overruns ? */
+        /* Display overruns? (for self-debug purpose) */
         { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
         /* Display CPU ? */
         { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
@@ -30,26 +38,137 @@ static struct tracer_opt trace_opts[] = {
         { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
         /* Display proc name/pid */
         { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
+        /* Display duration of execution */
+        { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
+        /* Display absolute time of an entry */
+        { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
         { } /* Empty entry */
 };
 
 static struct tracer_flags tracer_flags = {
         /* Don't display overruns and proc by default */
-        .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD,
+        .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
+               TRACE_GRAPH_PRINT_DURATION,
         .opts = trace_opts
 };
 
 /* pid on the last trace processed */
-static pid_t last_pid[NR_CPUS] = { [0 ... NR_CPUS-1] = -1 };
 
-static int graph_trace_init(struct trace_array *tr)
+
+/* Add a function return address to the trace stack on thread info.*/
+int
+ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
+                         unsigned long frame_pointer)
+{
+        unsigned long long calltime;
+        int index;
+
+        if (!current->ret_stack)
+                return -EBUSY;
+
+        /*
+         * We must make sure the ret_stack is tested before we read
+         * anything else.
+         */
+        smp_rmb();
+
+        /* The return trace stack is full */
+        if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
+                atomic_inc(&current->trace_overrun);
+                return -EBUSY;
+        }
+
+        calltime = trace_clock_local();
+
+        index = ++current->curr_ret_stack;
+        barrier();
+        current->ret_stack[index].ret = ret;
+        current->ret_stack[index].func = func;
+        current->ret_stack[index].calltime = calltime;
+        current->ret_stack[index].subtime = 0;
+        current->ret_stack[index].fp = frame_pointer;
+        *depth = index;
+
+        return 0;
+}
+
+/* Retrieve a function return address to the trace stack on thread info.*/
+static void
+ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
+                        unsigned long frame_pointer)
 {
-        int cpu, ret;
+        int index;
 
-        for_each_online_cpu(cpu)
-                tracing_reset(tr, cpu);
+        index = current->curr_ret_stack;
 
-        ret = register_ftrace_graph(&trace_graph_return,
+        if (unlikely(index < 0)) {
+                ftrace_graph_stop();
+                WARN_ON(1);
+                /* Might as well panic, otherwise we have no where to go */
+                *ret = (unsigned long)panic;
+                return;
+        }
+
+#ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
+        /*
+         * The arch may choose to record the frame pointer used
+         * and check it here to make sure that it is what we expect it
+         * to be. If gcc does not set the place holder of the return
+         * address in the frame pointer, and does a copy instead, then
+         * the function graph trace will fail. This test detects this
+         * case.
+         *
+         * Currently, x86_32 with optimize for size (-Os) makes the latest
+         * gcc do the above.
+         */
+        if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
+                ftrace_graph_stop();
+                WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
+                     "  from func %pF return to %lx\n",
+                     current->ret_stack[index].fp,
+                     frame_pointer,
+                     (void *)current->ret_stack[index].func,
+                     current->ret_stack[index].ret);
+                *ret = (unsigned long)panic;
+                return;
+        }
+#endif
+
+        *ret = current->ret_stack[index].ret;
+        trace->func = current->ret_stack[index].func;
+        trace->calltime = current->ret_stack[index].calltime;
+        trace->overrun = atomic_read(&current->trace_overrun);
+        trace->depth = index;
+}
+
+/*
+ * Send the trace to the ring-buffer.
+ * @return the original return address.
+ */
+unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
+{
+        struct ftrace_graph_ret trace;
+        unsigned long ret;
+
+        ftrace_pop_return_trace(&trace, &ret, frame_pointer);
+        trace.rettime = trace_clock_local();
+        ftrace_graph_return(&trace);
+        barrier();
+        current->curr_ret_stack--;
+
+        if (unlikely(!ret)) {
+                ftrace_graph_stop();
+                WARN_ON(1);
+                /* Might as well panic. What else to do? */
+                ret = (unsigned long)panic;
+        }
+
+        return ret;
+}
+
+static int graph_trace_init(struct trace_array *tr)
+{
+        int ret = register_ftrace_graph(&trace_graph_return,
                                         &trace_graph_entry);
         if (ret)
                 return ret;
@@ -112,15 +231,15 @@ print_graph_cpu(struct trace_seq *s, int cpu)
 static enum print_line_t
 print_graph_proc(struct trace_seq *s, pid_t pid)
 {
-        int i;
-        int ret;
-        int len;
-        char comm[8];
-        int spaces = 0;
+        char comm[TASK_COMM_LEN];
         /* sign + log10(MAX_INT) + '\0' */
         char pid_str[11];
+        int spaces = 0;
+        int ret;
+        int len;
+        int i;
 
-        strncpy(comm, trace_find_cmdline(pid), 7);
+        trace_find_cmdline(pid, comm);
         comm[7] = '\0';
         sprintf(pid_str, "%d", pid);
 
@@ -153,17 +272,25 @@ print_graph_proc(struct trace_seq *s, pid_t pid)
 
 /* If the pid changed since the last trace, output this event */
 static enum print_line_t
-verif_pid(struct trace_seq *s, pid_t pid, int cpu)
+verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 {
         pid_t prev_pid;
+        pid_t *last_pid;
         int ret;
 
-        if (last_pid[cpu] != -1 && last_pid[cpu] == pid)
+        if (!data)
+                return TRACE_TYPE_HANDLED;
+
+        last_pid = &(per_cpu_ptr(data, cpu)->last_pid);
+
+        if (*last_pid == pid)
                 return TRACE_TYPE_HANDLED;
 
-        prev_pid = last_pid[cpu];
-        last_pid[cpu] = pid;
+        prev_pid = *last_pid;
+        *last_pid = pid;
 
+        if (prev_pid == -1)
+                return TRACE_TYPE_HANDLED;
 /*
  * Context-switch trace line:
 
@@ -175,34 +302,34 @@ verif_pid(struct trace_seq *s, pid_t pid, int cpu)
         ret = trace_seq_printf(s,
                 " ------------------------------------------\n");
         if (!ret)
-                TRACE_TYPE_PARTIAL_LINE;
+                return TRACE_TYPE_PARTIAL_LINE;
 
         ret = print_graph_cpu(s, cpu);
         if (ret == TRACE_TYPE_PARTIAL_LINE)
-                TRACE_TYPE_PARTIAL_LINE;
+                return TRACE_TYPE_PARTIAL_LINE;
 
         ret = print_graph_proc(s, prev_pid);
         if (ret == TRACE_TYPE_PARTIAL_LINE)
-                TRACE_TYPE_PARTIAL_LINE;
+                return TRACE_TYPE_PARTIAL_LINE;
 
         ret = trace_seq_printf(s, " => ");
         if (!ret)
-                TRACE_TYPE_PARTIAL_LINE;
+                return TRACE_TYPE_PARTIAL_LINE;
 
         ret = print_graph_proc(s, pid);
         if (ret == TRACE_TYPE_PARTIAL_LINE)
-                TRACE_TYPE_PARTIAL_LINE;
+                return TRACE_TYPE_PARTIAL_LINE;
 
         ret = trace_seq_printf(s,
                 "\n ------------------------------------------\n\n");
         if (!ret)
-                TRACE_TYPE_PARTIAL_LINE;
+                return TRACE_TYPE_PARTIAL_LINE;
 
-        return ret;
+        return TRACE_TYPE_HANDLED;
 }
 
-static bool
-trace_branch_is_leaf(struct trace_iterator *iter,
+static struct ftrace_graph_ret_entry *
+get_return_for_leaf(struct trace_iterator *iter,
                 struct ftrace_graph_ent_entry *curr)
 {
         struct ring_buffer_iter *ring_iter;
@@ -211,72 +338,130 @@ trace_branch_is_leaf(struct trace_iterator *iter,
 
         ring_iter = iter->buffer_iter[iter->cpu];
 
-        if (!ring_iter)
-                return false;
-
-        event = ring_buffer_iter_peek(ring_iter, NULL);
+        /* First peek to compare current entry and the next one */
+        if (ring_iter)
+                event = ring_buffer_iter_peek(ring_iter, NULL);
+        else {
+        /* We need to consume the current entry to see the next one */
+                ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL);
+                event = ring_buffer_peek(iter->tr->buffer, iter->cpu,
+                                        NULL);
+        }
 
         if (!event)
-                return false;
+                return NULL;
 
         next = ring_buffer_event_data(event);
 
         if (next->ent.type != TRACE_GRAPH_RET)
-                return false;
+                return NULL;
 
         if (curr->ent.pid != next->ent.pid ||
                         curr->graph_ent.func != next->ret.func)
-                return false;
+                return NULL;
+
+        /* this is a leaf, now advance the iterator */
+        if (ring_iter)
+                ring_buffer_read(ring_iter, NULL);
+
+        return next;
+}
+
+/* Signal a overhead of time execution to the output */
+static int
+print_graph_overhead(unsigned long long duration, struct trace_seq *s)
+{
+        /* If duration disappear, we don't need anything */
+        if (!(tracer_flags.val & TRACE_GRAPH_PRINT_DURATION))
+                return 1;
+
+        /* Non nested entry or return */
+        if (duration == -1)
+                return trace_seq_printf(s, "  ");
+
+        if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
+                /* Duration exceeded 100 msecs */
+                if (duration > 100000ULL)
+                        return trace_seq_printf(s, "! ");
+
+                /* Duration exceeded 10 msecs */
+                if (duration > 10000ULL)
+                        return trace_seq_printf(s, "+ ");
+        }
 
-        return true;
+        return trace_seq_printf(s, "  ");
+}
+
+static int print_graph_abs_time(u64 t, struct trace_seq *s)
+{
+        unsigned long usecs_rem;
+
+        usecs_rem = do_div(t, NSEC_PER_SEC);
+        usecs_rem /= 1000;
+
+        return trace_seq_printf(s, "%5lu.%06lu |  ",
+                        (unsigned long)t, usecs_rem);
 }
 
 static enum print_line_t
-print_graph_irq(struct trace_seq *s, unsigned long addr,
-                                enum trace_type type, int cpu, pid_t pid)
+print_graph_irq(struct trace_iterator *iter, unsigned long addr,
+                enum trace_type type, int cpu, pid_t pid)
 {
         int ret;
+        struct trace_seq *s = &iter->seq;
 
         if (addr < (unsigned long)__irqentry_text_start ||
                 addr >= (unsigned long)__irqentry_text_end)
                 return TRACE_TYPE_UNHANDLED;
 
-        if (type == TRACE_GRAPH_ENT) {
-                ret = trace_seq_printf(s, "==========> |  ");
-        } else {
-                /* Cpu */
-                if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
-                        ret = print_graph_cpu(s, cpu);
-                        if (ret == TRACE_TYPE_PARTIAL_LINE)
-                                return TRACE_TYPE_PARTIAL_LINE;
-                }
-                /* Proc */
-                if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
-                        ret = print_graph_proc(s, pid);
-                        if (ret == TRACE_TYPE_PARTIAL_LINE)
-                                return TRACE_TYPE_PARTIAL_LINE;
+        /* Absolute time */
+        if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
+                ret = print_graph_abs_time(iter->ts, s);
+                if (!ret)
+                        return TRACE_TYPE_PARTIAL_LINE;
+        }
 
-                        ret = trace_seq_printf(s, " | ");
-                        if (!ret)
-                                return TRACE_TYPE_PARTIAL_LINE;
-                }
+        /* Cpu */
+        if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
+                ret = print_graph_cpu(s, cpu);
+                if (ret == TRACE_TYPE_PARTIAL_LINE)
+                        return TRACE_TYPE_PARTIAL_LINE;
+        }
+        /* Proc */
+        if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
+                ret = print_graph_proc(s, pid);
+                if (ret == TRACE_TYPE_PARTIAL_LINE)
+                        return TRACE_TYPE_PARTIAL_LINE;
+                ret = trace_seq_printf(s, " | ");
+                if (!ret)
+                        return TRACE_TYPE_PARTIAL_LINE;
+        }
 
-                /* No overhead */
-                if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
-                        ret = trace_seq_printf(s, "  ");
-                        if (!ret)
-                                return TRACE_TYPE_PARTIAL_LINE;
-                }
+        /* No overhead */
+        ret = print_graph_overhead(-1, s);
+        if (!ret)
+                return TRACE_TYPE_PARTIAL_LINE;
+
+        if (type == TRACE_GRAPH_ENT)
+                ret = trace_seq_printf(s, "==========>");
+        else
+                ret = trace_seq_printf(s, "<==========");
+
+        if (!ret)
+                return TRACE_TYPE_PARTIAL_LINE;
+
+        /* Don't close the duration column if haven't one */
+        if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
+                trace_seq_printf(s, " |");
+        ret = trace_seq_printf(s, "\n");
 
-                ret = trace_seq_printf(s, "<========== |\n");
-        }
         if (!ret)
                 return TRACE_TYPE_PARTIAL_LINE;
         return TRACE_TYPE_HANDLED;
 }
 
-static enum print_line_t
-print_graph_duration(unsigned long long duration, struct trace_seq *s)
+enum print_line_t
+trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 {
         unsigned long nsecs_rem = do_div(duration, 1000);
         /* log10(ULONG_MAX) + '\0' */
@@ -288,7 +473,7 @@ print_graph_duration(unsigned long long duration, struct trace_seq *s)
         sprintf(msecs_str, "%lu", (unsigned long) duration);
 
         /* Print msecs */
-        ret = trace_seq_printf(s, msecs_str);
+        ret = trace_seq_printf(s, "%s", msecs_str);
         if (!ret)
                 return TRACE_TYPE_PARTIAL_LINE;
 
@@ -313,60 +498,66 @@ print_graph_duration(unsigned long long duration, struct trace_seq *s)
                 if (!ret)
                         return TRACE_TYPE_PARTIAL_LINE;
         }
-
-        ret = trace_seq_printf(s, "|  ");
-        if (!ret)
-                return TRACE_TYPE_PARTIAL_LINE;
         return TRACE_TYPE_HANDLED;
-
 }
 
-/* Signal a overhead of time execution to the output */
-static int
-print_graph_overhead(unsigned long long duration, struct trace_seq *s)
+static enum print_line_t
+print_graph_duration(unsigned long long duration, struct trace_seq *s)
 {
-        /* Duration exceeded 100 msecs */
-        if (duration > 100000ULL)
-                return trace_seq_printf(s, "! ");
+        int ret;
 
-        /* Duration exceeded 10 msecs */
-        if (duration > 10000ULL)
-                return trace_seq_printf(s, "+ ");
+        ret = trace_print_graph_duration(duration, s);
+        if (ret != TRACE_TYPE_HANDLED)
+                return ret;
 
-        return trace_seq_printf(s, "  ");
+        ret = trace_seq_printf(s, "|  ");
+        if (!ret)
+                return TRACE_TYPE_PARTIAL_LINE;
+
+        return TRACE_TYPE_HANDLED;
 }
 
 /* Case of a leaf function on its call entry */
 static enum print_line_t
 print_graph_entry_leaf(struct trace_iterator *iter,
-                struct ftrace_graph_ent_entry *entry, struct trace_seq *s)
+                struct ftrace_graph_ent_entry *entry,
+                struct ftrace_graph_ret_entry *ret_entry, struct trace_seq *s)
 {
-        struct ftrace_graph_ret_entry *ret_entry;
+        struct fgraph_data *data = iter->private;
         struct ftrace_graph_ret *graph_ret;
-        struct ring_buffer_event *event;
         struct ftrace_graph_ent *call;
         unsigned long long duration;
         int ret;
         int i;
 
-        event = ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
-        ret_entry = ring_buffer_event_data(event);
         graph_ret = &ret_entry->ret;
         call = &entry->graph_ent;
         duration = graph_ret->rettime - graph_ret->calltime;
 
-        /* Overhead */
-        if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
-                ret = print_graph_overhead(duration, s);
-                if (!ret)
-                        return TRACE_TYPE_PARTIAL_LINE;
+        if (data) {
+                int cpu = iter->cpu;
+                int *depth = &(per_cpu_ptr(data, cpu)->depth);
+
+                /*
+                 * Comments display at + 1 to depth. Since
+                 * this is a leaf function, keep the comments
+                 * equal to this depth.
+                 */
+                *depth = call->depth - 1;
         }
 
-        /* Duration */
-        ret = print_graph_duration(duration, s);
-        if (ret == TRACE_TYPE_PARTIAL_LINE)
+        /* Overhead */
+        ret = print_graph_overhead(duration, s);
+        if (!ret)
                 return TRACE_TYPE_PARTIAL_LINE;
 
+        /* Duration */
+        if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
+                ret = print_graph_duration(duration, s);
+                if (ret == TRACE_TYPE_PARTIAL_LINE)
+                        return TRACE_TYPE_PARTIAL_LINE;
+        }
+
         /* Function */
         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
                 ret = trace_seq_printf(s, " ");
@@ -386,33 +577,34 @@ print_graph_entry_leaf(struct trace_iterator *iter,
 }
 
 static enum print_line_t
-print_graph_entry_nested(struct ftrace_graph_ent_entry *entry,
-                        struct trace_seq *s, pid_t pid, int cpu)
+print_graph_entry_nested(struct trace_iterator *iter,
+                         struct ftrace_graph_ent_entry *entry,
+                         struct trace_seq *s, int cpu)
 {
-        int i;
-        int ret;
         struct ftrace_graph_ent *call = &entry->graph_ent;
+        struct fgraph_data *data = iter->private;
+        int ret;
+        int i;
 
-        /* No overhead */
-        if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
-                ret = trace_seq_printf(s, "  ");
-                if (!ret)
-                        return TRACE_TYPE_PARTIAL_LINE;
+        if (data) {
+                int cpu = iter->cpu;
+                int *depth = &(per_cpu_ptr(data, cpu)->depth);
+
+                *depth = call->depth;
         }
 
-        /* Interrupt */
-        ret = print_graph_irq(s, call->func, TRACE_GRAPH_ENT, cpu, pid);
-        if (ret == TRACE_TYPE_UNHANDLED) {
-                /* No time */
+        /* No overhead */
+        ret = print_graph_overhead(-1, s);
+        if (!ret)
+                return TRACE_TYPE_PARTIAL_LINE;
+
+        /* No time */
+        if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
                 ret = trace_seq_printf(s, "            |  ");
                 if (!ret)
                         return TRACE_TYPE_PARTIAL_LINE;
-        } else {
-                if (ret == TRACE_TYPE_PARTIAL_LINE)
-                        return TRACE_TYPE_PARTIAL_LINE;
         }
 
-
         /* Function */
         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
                 ret = trace_seq_printf(s, " ");
@@ -428,20 +620,40 @@ print_graph_entry_nested(struct ftrace_graph_ent_entry *entry,
         if (!ret)
                 return TRACE_TYPE_PARTIAL_LINE;
 
-        return TRACE_TYPE_HANDLED;
+        /*
+         * we already consumed the current entry to check the next one
+         * and see if this is a leaf.
+         */
+        return TRACE_TYPE_NO_CONSUME;
 }
 
 static enum print_line_t
-print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
-                        struct trace_iterator *iter, int cpu)
+print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
+                     int type, unsigned long addr)
 {
-        int ret;
+        struct fgraph_data *data = iter->private;
         struct trace_entry *ent = iter->ent;
+        int cpu = iter->cpu;
+        int ret;
 
         /* Pid */
-        if (verif_pid(s, ent->pid, cpu) == TRACE_TYPE_PARTIAL_LINE)
+        if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
                 return TRACE_TYPE_PARTIAL_LINE;
 
+        if (type) {
+                /* Interrupt */
+                ret = print_graph_irq(iter, addr, type, cpu, ent->pid);
+                if (ret == TRACE_TYPE_PARTIAL_LINE)
+                        return TRACE_TYPE_PARTIAL_LINE;
+        }
+
+        /* Absolute time */
+        if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
+                ret = print_graph_abs_time(iter->ts, s);
+                if (!ret)
+                        return TRACE_TYPE_PARTIAL_LINE;
+        }
+
         /* Cpu */
         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
                 ret = print_graph_cpu(s, cpu);
@@ -460,54 +672,65 @@ print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
                         return TRACE_TYPE_PARTIAL_LINE;
         }
 
-        if (trace_branch_is_leaf(iter, field))
-                return print_graph_entry_leaf(iter, field, s);
+        return 0;
+}
+
+static enum print_line_t
+print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
+                        struct trace_iterator *iter)
+{
+        int cpu = iter->cpu;
+        struct ftrace_graph_ent *call = &field->graph_ent;
+        struct ftrace_graph_ret_entry *leaf_ret;
+
+        if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func))
+                return TRACE_TYPE_PARTIAL_LINE;
+
+        leaf_ret = get_return_for_leaf(iter, field);
+        if (leaf_ret)
+                return print_graph_entry_leaf(iter, field, leaf_ret, s);
         else
-                return print_graph_entry_nested(field, s, iter->ent->pid, cpu);
+                return print_graph_entry_nested(iter, field, s, cpu);
 
 }
 
 static enum print_line_t
 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
-                   struct trace_entry *ent, int cpu)
+                   struct trace_entry *ent, struct trace_iterator *iter)
 {
-        int i;
-        int ret;
         unsigned long long duration = trace->rettime - trace->calltime;
+        struct fgraph_data *data = iter->private;
+        pid_t pid = ent->pid;
+        int cpu = iter->cpu;
+        int ret;
+        int i;
 
-        /* Pid */
-        if (verif_pid(s, ent->pid, cpu) == TRACE_TYPE_PARTIAL_LINE)
-                return TRACE_TYPE_PARTIAL_LINE;
+        if (data) {
+                int cpu = iter->cpu;
+                int *depth = &(per_cpu_ptr(data, cpu)->depth);
 
-        /* Cpu */
-        if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
-                ret = print_graph_cpu(s, cpu);
-                if (ret == TRACE_TYPE_PARTIAL_LINE)
-                        return TRACE_TYPE_PARTIAL_LINE;
+                /*
+                 * Comments display at + 1 to depth. This is the
+                 * return from a function, we now want the comments
+                 * to display at the same level of the bracket.
+                 */
+                *depth = trace->depth - 1;
         }
 
-        /* Proc */
-        if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
-                ret = print_graph_proc(s, ent->pid);
-                if (ret == TRACE_TYPE_PARTIAL_LINE)
-                        return TRACE_TYPE_PARTIAL_LINE;
-
-                ret = trace_seq_printf(s, " | ");
-                if (!ret)
-                        return TRACE_TYPE_PARTIAL_LINE;
-        }
+        if (print_graph_prologue(iter, s, 0, 0))
+                return TRACE_TYPE_PARTIAL_LINE;
 
         /* Overhead */
-        if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
-                ret = print_graph_overhead(duration, s);
-                if (!ret)
-                        return TRACE_TYPE_PARTIAL_LINE;
-        }
+        ret = print_graph_overhead(duration, s);
+        if (!ret)
+                return TRACE_TYPE_PARTIAL_LINE;
 
         /* Duration */
-        ret = print_graph_duration(duration, s);
-        if (ret == TRACE_TYPE_PARTIAL_LINE)
-                return TRACE_TYPE_PARTIAL_LINE;
+        if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
+                ret = print_graph_duration(duration, s);
+                if (ret == TRACE_TYPE_PARTIAL_LINE)
+                        return TRACE_TYPE_PARTIAL_LINE;
+        }
 
         /* Closing brace */
         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
@@ -528,7 +751,7 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
                         return TRACE_TYPE_PARTIAL_LINE;
         }
 
-        ret = print_graph_irq(s, trace->func, TRACE_GRAPH_RET, cpu, ent->pid);
+        ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, cpu, pid);
         if (ret == TRACE_TYPE_PARTIAL_LINE)
                 return TRACE_TYPE_PARTIAL_LINE;
 
@@ -536,61 +759,73 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 }
 
 static enum print_line_t
-print_graph_comment(struct print_entry *trace, struct trace_seq *s,
-                   struct trace_entry *ent, struct trace_iterator *iter)
+print_graph_comment(struct trace_seq *s,  struct trace_entry *ent,
+                    struct trace_iterator *iter)
 {
-        int i;
+        unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
+        struct fgraph_data *data = iter->private;
+        struct trace_event *event;
+        int depth = 0;
         int ret;
+        int i;
 
-        /* Pid */
-        if (verif_pid(s, ent->pid, iter->cpu) == TRACE_TYPE_PARTIAL_LINE)
-                return TRACE_TYPE_PARTIAL_LINE;
-
-        /* Cpu */
-        if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
-                ret = print_graph_cpu(s, iter->cpu);
-                if (ret == TRACE_TYPE_PARTIAL_LINE)
-                        return TRACE_TYPE_PARTIAL_LINE;
-        }
+        if (data)
+                depth = per_cpu_ptr(data, iter->cpu)->depth;
 
-        /* Proc */
-        if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
-                ret = print_graph_proc(s, ent->pid);
-                if (ret == TRACE_TYPE_PARTIAL_LINE)
-                        return TRACE_TYPE_PARTIAL_LINE;
-
-                ret = trace_seq_printf(s, " | ");
-                if (!ret)
-                        return TRACE_TYPE_PARTIAL_LINE;
-        }
+        if (print_graph_prologue(iter, s, 0, 0))
+                return TRACE_TYPE_PARTIAL_LINE;
 
         /* No overhead */
-        if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
-                ret = trace_seq_printf(s, "  ");
+        ret = print_graph_overhead(-1, s);
+        if (!ret)
+                return TRACE_TYPE_PARTIAL_LINE;
+
+        /* No time */
+        if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
+                ret = trace_seq_printf(s, "            |  ");
                 if (!ret)
                         return TRACE_TYPE_PARTIAL_LINE;
         }
 
-        /* No time */
-        ret = trace_seq_printf(s, "            |  ");
-        if (!ret)
-                return TRACE_TYPE_PARTIAL_LINE;
-
         /* Indentation */
-        if (trace->depth > 0)
-                for (i = 0; i < (trace->depth + 1) * TRACE_GRAPH_INDENT; i++) {
+        if (depth > 0)
+                for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
                         ret = trace_seq_printf(s, " ");
                         if (!ret)
                                 return TRACE_TYPE_PARTIAL_LINE;
                 }
 
         /* The comment */
-        ret = trace_seq_printf(s, "/* %s", trace->buf);
+        ret = trace_seq_printf(s, "/* ");
         if (!ret)
                 return TRACE_TYPE_PARTIAL_LINE;
 
-        if (ent->flags & TRACE_FLAG_CONT)
-                trace_seq_print_cont(s, iter);
+        switch (iter->ent->type) {
+        case TRACE_BPRINT:
+                ret = trace_print_bprintk_msg_only(iter);
+                if (ret != TRACE_TYPE_HANDLED)
+                        return ret;
+                break;
+        case TRACE_PRINT:
+                ret = trace_print_printk_msg_only(iter);
+                if (ret != TRACE_TYPE_HANDLED)
+                        return ret;
+                break;
+        default:
+                event = ftrace_find_event(ent->type);
+                if (!event)
+                        return TRACE_TYPE_UNHANDLED;
+
+                ret = event->trace(iter, sym_flags);
+                if (ret != TRACE_TYPE_HANDLED)
+                        return ret;
+        }
+
+        /* Strip ending newline */
+        if (s->buffer[s->len - 1] == '\n') {
+                s->buffer[s->len - 1] = '\0';
+                s->len--;
+        }
 
         ret = trace_seq_printf(s, " */\n");
         if (!ret)
@@ -603,62 +838,98 @@ print_graph_comment(struct print_entry *trace, struct trace_seq *s,
 enum print_line_t
 print_graph_function(struct trace_iterator *iter)
 {
-        struct trace_seq *s = &iter->seq;
         struct trace_entry *entry = iter->ent;
+        struct trace_seq *s = &iter->seq;
 
         switch (entry->type) {
         case TRACE_GRAPH_ENT: {
-                struct ftrace_graph_ent_entry *field;
+                /*
+                 * print_graph_entry() may consume the current event,
+                 * thus @field may become invalid, so we need to save it.
+                 * sizeof(struct ftrace_graph_ent_entry) is very small,
+                 * it can be safely saved at the stack.
+                 */
+                struct ftrace_graph_ent_entry *field, saved;
                 trace_assign_type(field, entry);
-                return print_graph_entry(field, s, iter,
-                                         iter->cpu);
+                saved = *field;
+                return print_graph_entry(&saved, s, iter);
         }
         case TRACE_GRAPH_RET: {
                 struct ftrace_graph_ret_entry *field;
                 trace_assign_type(field, entry);
-                return print_graph_return(&field->ret, s, entry, iter->cpu);
-        }
-        case TRACE_PRINT: {
-                struct print_entry *field;
-                trace_assign_type(field, entry);
-                return print_graph_comment(field, s, entry, iter);
+                return print_graph_return(&field->ret, s, entry, iter);
         }
         default:
-                return TRACE_TYPE_UNHANDLED;
+                return print_graph_comment(s, entry, iter);
         }
+
+        return TRACE_TYPE_HANDLED;
 }
 
 static void print_graph_headers(struct seq_file *s)
 {
         /* 1st line */
         seq_printf(s, "# ");
+        if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
+                seq_printf(s, "     TIME       ");
         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
-                seq_printf(s, "CPU ");
+                seq_printf(s, "CPU");
         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
-                seq_printf(s, "TASK/PID     ");
-        if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD)
-                seq_printf(s, "OVERHEAD/");
-        seq_printf(s, "DURATION            FUNCTION CALLS\n");
+                seq_printf(s, "  TASK/PID      ");
+        if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
+                seq_printf(s, "  DURATION   ");
+        seq_printf(s, "               FUNCTION CALLS\n");
 
         /* 2nd line */
         seq_printf(s, "# ");
+        if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
+                seq_printf(s, "      |         ");
         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
-                seq_printf(s, "|   ");
+                seq_printf(s, "|  ");
         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
-                seq_printf(s, "|      |     ");
-        if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
-                seq_printf(s, "|        ");
-                seq_printf(s, "|                   |   |   |   |\n");
-        } else
-                seq_printf(s, "    |               |   |   |   |\n");
+                seq_printf(s, "  |    |        ");
+        if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
+                seq_printf(s, "   |   |      ");
+        seq_printf(s, "               |   |   |   |\n");
 }
+
+static void graph_trace_open(struct trace_iterator *iter)
+{
+        /* pid and depth on the last trace processed */
+        struct fgraph_data *data = alloc_percpu(struct fgraph_data);
+        int cpu;
+
+        if (!data)
+                pr_warning("function graph tracer: not enough memory\n");
+        else
+                for_each_possible_cpu(cpu) {
+                        pid_t *pid = &(per_cpu_ptr(data, cpu)->last_pid);
+                        int *depth = &(per_cpu_ptr(data, cpu)->depth);
+                        *pid = -1;
+                        *depth = 0;
+                }
+
+        iter->private = data;
+}
+
+static void graph_trace_close(struct trace_iterator *iter)
+{
+        free_percpu(iter->private);
+}
+
 static struct tracer graph_trace __read_mostly = {
-        .name           = "function_graph",
-        .init           = graph_trace_init,
-        .reset          = graph_trace_reset,
+        .name           = "function_graph",
+        .open           = graph_trace_open,
+        .close          = graph_trace_close,
+        .wait_pipe      = poll_wait_pipe,
+        .init           = graph_trace_init,
+        .reset          = graph_trace_reset,
         .print_line     = print_graph_function,
         .print_header   = print_graph_headers,
         .flags          = &tracer_flags,
+#ifdef CONFIG_FTRACE_SELFTEST
+        .selftest       = trace_selftest_startup_function_graph,
+#endif
 };
 
 static __init int init_graph_trace(void)