Add TRACE() debug tracing support

This patch adds the infrastructure for the TRACE() debug macro.

1 files changed, 12 insertions, 1 deletions

diff --git a/kernel/printk.c b/kernel/printk.c
index d37d45c90ae6..5616e59096a5 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -66,6 +66,13 @@ int console_printk[4] = {
 };
 
 /*
+ * divert printk() messages when there is a LITMUS^RT debug listener
+ */
+#include <litmus/debug_trace.h>
+int trace_override = 0;
+int trace_recurse  = 0;
+
+/*
  * Low level drivers may need that to know if they can schedule in
  * their unblank() callback or not. So let's export it.
  */
@@ -1552,6 +1559,10 @@ asmlinkage int vprintk_emit(int facility, int level,
          */
         text_len = vscnprintf(text, sizeof(textbuf), fmt, args);
 
+        /* if LITMUS^RT tracer is active divert printk() msgs */
+        if (trace_override && !trace_recurse)
+                TRACE("%s", text);
+
         /* mark and strip a trailing newline */
         if (text_len && text[text_len-1] == '\n') {
                 text_len--;
@@ -2478,7 +2489,7 @@ static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = {
 void wake_up_klogd(void)
 {
         preempt_disable();
-        if (waitqueue_active(&log_wait)) {
+        if (!trace_override && waitqueue_active(&log_wait)) {
                 this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
                 irq_work_queue(&__get_cpu_var(wake_up_klogd_work));
         }