3 files changed, 20 insertions, 10 deletions

diff --git a/Documentation/ftrace.txt b/Documentation/ftrace.txt
index d330fe3103da..ea5a827395dd 100644
--- a/Documentation/ftrace.txt
+++ b/Documentation/ftrace.txt
@@ -291,6 +291,9 @@ explains which is which.
   CPU#: The CPU which the process was running on.
 
   irqs-off: 'd' interrupts are disabled. '.' otherwise.
+            Note: If the architecture does not support a way to
+                  read the irq flags variable, an 'X' will always
+                  be printed here.
 
   need-resched: 'N' task need_resched is set, '.' otherwise.
 
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a610ca771558..8a499e2adaec 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -656,7 +656,11 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
         entry->preempt_count            = pc & 0xff;
         entry->pid                      = (tsk) ? tsk->pid : 0;
         entry->flags =
+#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
                 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
+#else
+                TRACE_FLAG_IRQS_NOSUPPORT |
+#endif
                 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
                 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
                 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
@@ -1244,7 +1248,8 @@ lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
         trace_seq_printf(s, "%8.8s-%-5d ", comm, entry->pid);
         trace_seq_printf(s, "%3d", cpu);
         trace_seq_printf(s, "%c%c",
-                        (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' : '.',
+                        (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
+                         (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' : '.',
                         ((entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.'));
 
         hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 6889ca48f1f1..8465ad052707 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -120,18 +120,20 @@ struct trace_boot {
 /*
  * trace_flag_type is an enumeration that holds different
  * states when a trace occurs. These are:
- *  IRQS_OFF    - interrupts were disabled
- *  NEED_RESCED - reschedule is requested
- *  HARDIRQ     - inside an interrupt handler
- *  SOFTIRQ     - inside a softirq handler
- *  CONT        - multiple entries hold the trace item
+ *  IRQS_OFF            - interrupts were disabled
+ *  IRQS_NOSUPPORT      - arch does not support irqs_disabled_flags
+ *  NEED_RESCED         - reschedule is requested
+ *  HARDIRQ             - inside an interrupt handler
+ *  SOFTIRQ             - inside a softirq handler
+ *  CONT                - multiple entries hold the trace item
  */
 enum trace_flag_type {
         TRACE_FLAG_IRQS_OFF             = 0x01,
-        TRACE_FLAG_NEED_RESCHED         = 0x02,
-        TRACE_FLAG_HARDIRQ              = 0x04,
-        TRACE_FLAG_SOFTIRQ              = 0x08,
-        TRACE_FLAG_CONT                 = 0x10,
+        TRACE_FLAG_IRQS_NOSUPPORT       = 0x02,
+        TRACE_FLAG_NEED_RESCHED         = 0x04,
+        TRACE_FLAG_HARDIRQ              = 0x08,
+        TRACE_FLAG_SOFTIRQ              = 0x10,
+        TRACE_FLAG_CONT                 = 0x20,
 };
 
 #define TRACE_BUF_SIZE          1024