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, 52 insertions, 0 deletions

diff --git a/src/kern/linux/events.hh b/src/kern/linux/events.hh
index 3f5f2526f..b8aad9d79 100644
--- a/src/kern/linux/events.hh
+++ b/src/kern/linux/events.hh
@@ -1,4 +1,16 @@
 /*
+ * Copyright (c) 2016 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
  * Copyright (c) 2004-2006 The Regents of The University of Michigan
  * All rights reserved.
  *
@@ -44,6 +56,46 @@ class DebugPrintkEvent : public SkipFuncEvent
     virtual void process(ThreadContext *xc);
 };
 
+/**
+ * Dump the guest kernel's dmesg buffer to a file in gem5's output
+ * directory and print a warning.
+ *
+ * @warn This event uses Linux::dumpDmesg() and comes with the same
+ * limitations. Most importantly, the kernel's address mappings must
+ * be available to the translating proxy.
+ */
+class DmesgDumpEvent : public PCEvent
+{
+  protected:
+    std::string fname;
+
+  public:
+    DmesgDumpEvent(PCEventQueue *q, const std::string &desc, Addr addr,
+                   const std::string &_fname)
+        : PCEvent(q, desc, addr), fname(_fname) {}
+    virtual void process(ThreadContext *xc);
+};
+
+/**
+ * Dump the guest kernel's dmesg buffer to a file in gem5's output
+ * directory and panic.
+ *
+ * @warn This event uses Linux::dumpDmesg() and comes with the same
+ * limitations. Most importantly, the kernel's address mappings must
+ * be available to the translating proxy.
+ */
+class KernelPanicEvent : public PCEvent
+{
+  protected:
+    std::string fname;
+
+  public:
+    KernelPanicEvent(PCEventQueue *q, const std::string &desc, Addr addr,
+               const std::string &_fname)
+        : PCEvent(q, desc, addr), fname(_fname) {}
+    virtual void process(ThreadContext *xc);
+};
+
 /** A class to skip udelay() and related calls in the kernel.
  * This class has two additional parameters that take the argument to udelay and
  * manipulated it to come up with ns and eventually ticks to quiesce for.