kern, arm: Dump dmesg on kernel panic/oops

Add helper functions to dump the guest kernel's dmesg buffer to a text
file in m5out. This functionality is split into two parts. First, a
dmesg dump function that can be used in other places:

void Linux::dumpDmesg(ThreadContext *, std::ostream &)

This function is used to implement two PCEvents: DmesgDumpEvent and
KernelPanic event. The only difference between the two is that the
latter produces a gem5 panic instead of a warning in addition to
dumping the kernel log.

Change-Id: I6d2af1d666ace57124089648ea906f6c787ac63c
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Gabor Dozsa <gabor.dozsa@arm.com>

1 files changed, 31 insertions, 2 deletions

diff --git a/src/kern/linux/events.cc b/src/kern/linux/events.cc
index 42f058a72..f4e694436 100644
--- a/src/kern/linux/events.cc
+++ b/src/kern/linux/events.cc
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011 ARM Limited
+ * Copyright (c) 2011, 2016 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -41,13 +41,17 @@
  *          Ali Saidi
  */
 
+#include "kern/linux/events.hh"
+
 #include <sstream>
 
 #include "arch/utility.hh"
+#include "base/output.hh"
 #include "base/trace.hh"
+#include "cpu/base.hh"
 #include "cpu/thread_context.hh"
 #include "debug/DebugPrintf.hh"
-#include "kern/linux/events.hh"
+#include "kern/linux/helpers.hh"
 #include "kern/linux/printk.hh"
 #include "kern/system_events.hh"
 #include "sim/arguments.hh"
@@ -94,5 +98,30 @@ UDelayEvent::process(ThreadContext *tc)
     }
 }
 
+void
+DmesgDumpEvent::process(ThreadContext *tc)
+{
+    StringWrap name(tc->getCpuPtr()->name() + ".dmesg_dump_event");
+
+    inform("Dumping kernel dmesg buffer to %s...\n", fname);
+    OutputStream *os = simout.create(fname);
+    dumpDmesg(tc, *os->stream());
+    simout.close(os);
+
+    warn(descr());
+}
+
+void
+KernelPanicEvent::process(ThreadContext *tc)
+{
+    StringWrap name(tc->getCpuPtr()->name() + ".dmesg_dump_event");
+
+    inform("Dumping kernel dmesg buffer to %s...\n", fname);
+    OutputStream *os = simout.create(fname);
+    dumpDmesg(tc, *os->stream());
+    simout.close(os);
+
+    panic(descr());
+}
 
 } // namespace linux