1 files changed, 123 insertions, 3 deletions

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 6f233698518e..02c708ae0d42 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -15,15 +15,19 @@
 #include "trace.h"
 #include "trace_output.h"
 
+/* When set, irq functions will be ignored */
+static int ftrace_graph_skip_irqs;
+
 struct fgraph_cpu_data {
         pid_t           last_pid;
         int             depth;
+        int             depth_irq;
         int             ignore;
         unsigned long   enter_funcs[FTRACE_RETFUNC_DEPTH];
 };
 
 struct fgraph_data {
-        struct fgraph_cpu_data          *cpu_data;
+        struct fgraph_cpu_data __percpu *cpu_data;
 
         /* Place to preserve last processed entry. */
         struct ftrace_graph_ent_entry   ent;
@@ -41,6 +45,7 @@ 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 +60,15 @@ 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
 };
 
@@ -204,6 +211,14 @@ int __trace_graph_entry(struct trace_array *tr,
         return 1;
 }
 
+static inline int ftrace_graph_ignore_irqs(void)
+{
+        if (!ftrace_graph_skip_irqs)
+                return 0;
+
+        return in_irq();
+}
+
 int trace_graph_entry(struct ftrace_graph_ent *trace)
 {
         struct trace_array *tr = graph_array;
@@ -218,7 +233,8 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
                 return 0;
 
         /* trace it when it is-nested-in or is a function enabled. */
-        if (!(trace->depth || ftrace_graph_addr(trace->func)))
+        if (!(trace->depth || ftrace_graph_addr(trace->func)) ||
+              ftrace_graph_ignore_irqs())
                 return 0;
 
         local_irq_save(flags);
@@ -855,6 +871,92 @@ 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 +967,9 @@ 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 +1007,9 @@ 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 +1318,12 @@ 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;
@@ -1235,6 +1346,14 @@ void graph_trace_close(struct trace_iterator *iter)
         }
 }
 
+static int func_graph_set_flag(u32 old_flags, u32 bit, int set)
+{
+        if (bit == TRACE_GRAPH_PRINT_IRQS)
+                ftrace_graph_skip_irqs = !set;
+
+        return 0;
+}
+
 static struct trace_event_functions graph_functions = {
         .trace          = print_graph_function_event,
 };
@@ -1261,6 +1380,7 @@ static struct tracer graph_trace __read_mostly = {
         .print_line     = print_graph_function,
         .print_header   = print_graph_headers,
         .flags          = &tracer_flags,
+        .set_flag       = func_graph_set_flag,
 #ifdef CONFIG_FTRACE_SELFTEST
         .selftest       = trace_selftest_startup_function_graph,
 #endif