1 /*
2 * Stacktrace support for Hexagon
3 *
4 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 and
8 * only version 2 as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
18 * 02110-1301, USA.
19 */
20
21 #include <linux/sched.h>
22 #include <linux/sched/task_stack.h>
23 #include <linux/stacktrace.h>
24 #include <linux/thread_info.h>
25 #include <linux/module.h>
26
27 struct stackframe {
28 unsigned long fp;
29 unsigned long rets;
30 };
31
32 /*
33 * Save stack-backtrace addresses into a stack_trace buffer.
34 */
save_stack_trace(struct stack_trace * trace)35 void save_stack_trace(struct stack_trace *trace)
36 {
37 unsigned long low, high;
38 unsigned long fp;
39 struct stackframe *frame;
40 int skip = trace->skip;
41
42 low = (unsigned long)task_stack_page(current);
43 high = low + THREAD_SIZE;
44 fp = (unsigned long)__builtin_frame_address(0);
45
46 while (fp >= low && fp <= (high - sizeof(*frame))) {
47 frame = (struct stackframe *)fp;
48
49 if (skip) {
50 skip--;
51 } else {
52 trace->entries[trace->nr_entries++] = frame->rets;
53 if (trace->nr_entries >= trace->max_entries)
54 break;
55 }
56
57 /*
58 * The next frame must be at a higher address than the
59 * current frame.
60 */
61 low = fp + sizeof(*frame);
62 fp = frame->fp;
63 }
64 }
65 EXPORT_SYMBOL_GPL(save_stack_trace);
66