1 files changed, 100 insertions, 1 deletions

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index c93bcb248638..8674750a5ece 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -18,6 +18,7 @@
 struct fgraph_cpu_data {
         pid_t           last_pid;
         int             depth;
+        int             depth_irq;
         int             ignore;
         unsigned long   enter_funcs[FTRACE_RETFUNC_DEPTH];
 };
@@ -41,6 +42,7 @@ struct fgraph_data {
 #define TRACE_GRAPH_PRINT_PROC          0x8
 #define TRACE_GRAPH_PRINT_DURATION      0x10
 #define TRACE_GRAPH_PRINT_ABS_TIME      0x20
+#define TRACE_GRAPH_PRINT_IRQS          0x40
 
 static struct tracer_opt trace_opts[] = {
         /* Display overruns? (for self-debug purpose) */
@@ -55,13 +57,15 @@ static struct tracer_opt trace_opts[] = {
         { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
         /* Display absolute time of an entry */
         { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
+        /* Display interrupts */
+        { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
         { } /* 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 |
-               TRACE_GRAPH_PRINT_DURATION,
+               TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS,
         .opts = trace_opts
 };
 
@@ -855,6 +859,92 @@ print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
         return 0;
 }
 
+/*
+ * Entry check for irq code
+ *
+ * returns 1 if
+ *  - we are inside irq code
+ *  - we just extered irq code
+ *
+ * retunns 0 if
+ *  - funcgraph-interrupts option is set
+ *  - we are not inside irq code
+ */
+static int
+check_irq_entry(struct trace_iterator *iter, u32 flags,
+                unsigned long addr, int depth)
+{
+        int cpu = iter->cpu;
+        struct fgraph_data *data = iter->private;
+        int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
+
+        if (flags & TRACE_GRAPH_PRINT_IRQS)
+                return 0;
+
+        /*
+         * We are inside the irq code
+         */
+        if (*depth_irq >= 0)
+                return 1;
+
+        if ((addr < (unsigned long)__irqentry_text_start) ||
+            (addr >= (unsigned long)__irqentry_text_end))
+                return 0;
+
+        /*
+         * We are entering irq code.
+         */
+        *depth_irq = depth;
+        return 1;
+}
+
+/*
+ * Return check for irq code
+ *
+ * returns 1 if
+ *  - we are inside irq code
+ *  - we just left irq code
+ *
+ * returns 0 if
+ *  - funcgraph-interrupts option is set
+ *  - we are not inside irq code
+ */
+static int
+check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
+{
+        int cpu = iter->cpu;
+        struct fgraph_data *data = iter->private;
+        int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
+
+        if (flags & TRACE_GRAPH_PRINT_IRQS)
+                return 0;
+
+        /*
+         * We are not inside the irq code.
+         */
+        if (*depth_irq == -1)
+                return 0;
+
+        /*
+         * We are inside the irq code, and this is returning entry.
+         * Let's not trace it and clear the entry depth, since
+         * we are out of irq code.
+         *
+         * This condition ensures that we 'leave the irq code' once
+         * we are out of the entry depth. Thus protecting us from
+         * the RETURN entry loss.
+         */
+        if (*depth_irq >= depth) {
+                *depth_irq = -1;
+                return 1;
+        }
+
+        /*
+         * We are inside the irq code, and this is not the entry.
+         */
+        return 1;
+}
+
 static enum print_line_t
 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
                         struct trace_iterator *iter, u32 flags)
@@ -865,6 +955,9 @@ print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
         static enum print_line_t ret;
         int cpu = iter->cpu;
 
+        if (check_irq_entry(iter, flags, call->func, call->depth))
+                return TRACE_TYPE_HANDLED;
+
         if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags))
                 return TRACE_TYPE_PARTIAL_LINE;
 
@@ -902,6 +995,9 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
         int ret;
         int i;
 
+        if (check_irq_return(iter, flags, trace->depth))
+                return TRACE_TYPE_HANDLED;
+
         if (data) {
                 struct fgraph_cpu_data *cpu_data;
                 int cpu = iter->cpu;
@@ -1210,9 +1306,12 @@ void graph_trace_open(struct trace_iterator *iter)
                 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
                 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
                 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
+                int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
+
                 *pid = -1;
                 *depth = 0;
                 *ignore = 0;
+                *depth_irq = -1;
         }
 
         iter->private = data;