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/sched/task_stack.h>
17 #include <linux/stacktrace.h>
18
19 #include <asm/processor.h>
20 #include <asm/unwinder.h>
21
22 /*
23 * Save stack-backtrace addresses into a stack_trace buffer.
24 */
25 static void
26 save_stack_address(void *data, unsigned long addr, int reliable)
27 {
28 struct stack_trace *trace = data;
29
30 if (!reliable)
31 return;
32
33 if (trace->skip > 0) {
34 trace->skip--;
35 return;
36 }
37
38 if (trace->nr_entries < trace->max_entries)
39 trace->entries[trace->nr_entries++] = addr;
40 }
41
42 void save_stack_trace(struct stack_trace *trace)
43 {
44 unwind_stack(trace, (unsigned long *) &trace, save_stack_address);
45 }
46 EXPORT_SYMBOL_GPL(save_stack_trace);
47
48 static void
49 save_stack_address_nosched(void *data, unsigned long addr, int reliable)
50 {
51 struct stack_trace *trace = (struct stack_trace *)data;
52
53 if (!reliable)
54 return;
55
56 if (in_sched_functions(addr))
57 return;
58
59 if (trace->skip > 0) {
60 trace->skip--;
61 return;
62 }
63
64 if (trace->nr_entries < trace->max_entries)
65 trace->entries[trace->nr_entries++] = addr;
66 }
67
68 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
69 {
70 unsigned long *sp = NULL;
71
72 if (!try_get_task_stack(tsk))
73 return;
74
75 if (tsk == current)
76 sp = (unsigned long *) &sp;
77 else {
78 unsigned long ksp;
79
80 /* Locate stack from kernel context */
81 ksp = task_thread_info(tsk)->ksp;
82 ksp += STACK_FRAME_OVERHEAD; /* redzone */
83 ksp += sizeof(struct pt_regs);
84
85 sp = (unsigned long *) ksp;
86 }
87
88 unwind_stack(trace, sp, save_stack_address_nosched);
89
90 put_task_stack(tsk);
91 }
92 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
93
94 void
95 save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
96 {
97 unwind_stack(trace, (unsigned long *) regs->sp,
98 save_stack_address_nosched);
99 }
100 EXPORT_SYMBOL_GPL(save_stack_trace_regs);
101
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