[ported from 2008.3] Add tracing support and hook up Litmus KConfig for x86

- fix requesting more than 2^11 pages (MAX_ORDER)
  to system allocator

Still to be merged:
- feather-trace generic implementation

1 files changed, 12 insertions, 2 deletions

diff --git a/kernel/printk.c b/kernel/printk.c
index f38b07f78a4e..6712a252b306 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -70,6 +70,13 @@ int console_printk[4] = {
 static int saved_console_loglevel = -1;
 
 /*
+ * divert printk() messages when there is a LITMUS^RT debug listener
+ */
+#include <litmus/litmus.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.
  */
@@ -713,6 +720,9 @@ asmlinkage int vprintk(const char *fmt, va_list args)
         /* Emit the output into the temporary buffer */
         printed_len += vscnprintf(printk_buf + printed_len,
                                   sizeof(printk_buf) - printed_len, fmt, args);
+        /* if LITMUS^RT tracer is active divert printk() msgs */
+        if (trace_override && !trace_recurse)
+                TRACE("%s", printk_buf);
 
 
         p = printk_buf;
@@ -782,7 +792,7 @@ asmlinkage int vprintk(const char *fmt, va_list args)
          * Try to acquire and then immediately release the
          * console semaphore. The release will do all the
          * actual magic (print out buffers, wake up klogd,
-         * etc). 
+         * etc).
          *
          * The acquire_console_semaphore_for_printk() function
          * will release 'logbuf_lock' regardless of whether it
@@ -1019,7 +1029,7 @@ int printk_needs_cpu(int cpu)
 
 void wake_up_klogd(void)
 {
-        if (waitqueue_active(&log_wait))
+        if (!trace_override && waitqueue_active(&log_wait))
                 __raw_get_cpu_var(printk_pending) = 1;
 }