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  */
24 static void
25 save_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 
41 void save_stack_trace(struct stack_trace *trace)
42 {
43 	unwind_stack(trace, (unsigned long *) &trace, save_stack_address);
44 }
45 EXPORT_SYMBOL_GPL(save_stack_trace);
46 
47 static void
48 save_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 
67 void 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 }
78 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
79 
80 void
81 save_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 }
86 EXPORT_SYMBOL_GPL(save_stack_trace_regs);
87