From 060287b8c467bf49a594d8d669e1986c6d8d76b0 Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Mon, 9 Jul 2012 17:10:41 -0700 Subject: 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 (according to sign-off history). I reworked the driver a little bit, and ported it to pstore. Signed-off-by: Anton Vorontsov Signed-off-by: Greg Kroah-Hartman --- fs/pstore/ftrace.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 fs/pstore/ftrace.c (limited to 'fs/pstore/ftrace.c') diff --git a/fs/pstore/ftrace.c b/fs/pstore/ftrace.c new file mode 100644 index 00000000000..a130d484b7d --- /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 +#include +#include +#include +#include +#include +#include +#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); +} -- cgit v1.2.3-70-g09d2