1/*
 2 * Stack trace utility for OpenRISC
 3 *
 4 * Copyright (C) 2017 Stafford Horne <shorne@gmail.com>
 5 *
 6 * This file is licensed under the terms of the GNU General Public License
 7 * version 2.  This program is licensed "as is" without any warranty of any
 8 * kind, whether express or implied.
 9 *
10 * Losely based on work from sh and powerpc.
11 */
12
13#include <linux/export.h>
14#include <linux/sched.h>
15#include <linux/sched/debug.h>
16#include <linux/stacktrace.h>
17
18#include <asm/processor.h>
19#include <asm/unwinder.h>
20
21/*
22 * Save stack-backtrace addresses into a stack_trace buffer.
23 */
24static void
25save_stack_address(void *data, unsigned long addr, int reliable)
26{
27	struct stack_trace *trace = data;
28
29	if (!reliable)
30		return;
31
32	if (trace->skip > 0) {
33		trace->skip--;
34		return;
35	}
36
37	if (trace->nr_entries < trace->max_entries)
38		trace->entries[trace->nr_entries++] = addr;
39}
40
41void save_stack_trace(struct stack_trace *trace)
42{
43	unwind_stack(trace, (unsigned long *) &trace, save_stack_address);
44}
45EXPORT_SYMBOL_GPL(save_stack_trace);
46
47static void
48save_stack_address_nosched(void *data, unsigned long addr, int reliable)
49{
50	struct stack_trace *trace = (struct stack_trace *)data;
51
52	if (!reliable)
53		return;
54
55	if (in_sched_functions(addr))
56		return;
57
58	if (trace->skip > 0) {
59		trace->skip--;
60		return;
61	}
62
63	if (trace->nr_entries < trace->max_entries)
64		trace->entries[trace->nr_entries++] = addr;
65}
66
67void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
68{
69	unsigned long *sp = NULL;
70
71	if (tsk == current)
72		sp = (unsigned long *) &sp;
73	else
74		sp = (unsigned long *) KSTK_ESP(tsk);
75
76	unwind_stack(trace, sp, save_stack_address_nosched);
77}
78EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
79
80void
81save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
82{
83	unwind_stack(trace, (unsigned long *) regs->sp,
84		     save_stack_address_nosched);
85}
86EXPORT_SYMBOL_GPL(save_stack_trace_regs);