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authorAnton Vorontsov <anton.vorontsov@linaro.org>2012-07-10 04:10:41 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-07-17 21:05:52 +0400
commit060287b8c467bf49a594d8d669e1986c6d8d76b0 (patch)
treef869d1cc6d09875a0dc4f42b230f144617fc3bfc /fs/pstore/ftrace.c
parent897dba027445be93f40e5caf550556ca38c48c51 (diff)
downloadlinux-060287b8c467bf49a594d8d669e1986c6d8d76b0.tar.xz
pstore: Add persistent function tracing
With this support kernel can save function call chain log into a persistent ram buffer that can be decoded and dumped after reboot through pstore filesystem. It can be used to determine what function was last called before a reset or panic. We store the log in a binary format and then decode it at read time. p.s. Mostly the code comes from trace_persistent.c driver found in the Android git tree, written by Colin Cross <ccross@android.com> (according to sign-off history). I reworked the driver a little bit, and ported it to pstore. Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/pstore/ftrace.c')
-rw-r--r--fs/pstore/ftrace.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/fs/pstore/ftrace.c b/fs/pstore/ftrace.c
new file mode 100644
index 000000000000..a130d484b7d3
--- /dev/null
+++ b/fs/pstore/ftrace.c
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2012 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/compiler.h>
+#include <linux/irqflags.h>
+#include <linux/percpu.h>
+#include <linux/smp.h>
+#include <linux/atomic.h>
+#include <asm/barrier.h>
+#include "internal.h"
+
+void notrace pstore_ftrace_call(unsigned long ip, unsigned long parent_ip)
+{
+ struct pstore_ftrace_record rec = {};
+
+ if (unlikely(oops_in_progress))
+ return;
+
+ rec.ip = ip;
+ rec.parent_ip = parent_ip;
+ pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id());
+ psinfo->write_buf(PSTORE_TYPE_FTRACE, 0, NULL, 0, (void *)&rec,
+ sizeof(rec), psinfo);
+}