1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 * Copyright (C) 2013 Richard Weinberger <richard@nod.at>
5 * Copyright (C) 2014 Google Inc., Author: Daniel Walter <dwalter@google.com>
6 */
7
8#include <linux/kallsyms.h>
9#include <linux/kernel.h>
10#include <linux/sched.h>
11#include <linux/stacktrace.h>
12#include <linux/module.h>
13#include <linux/uaccess.h>
14#include <asm/stacktrace.h>
15
16void dump_trace(struct task_struct *tsk,
17		const struct stacktrace_ops *ops,
18		void *data)
19{
20	int reliable = 0;
21	unsigned long *sp, bp, addr;
22	struct pt_regs *segv_regs = tsk->thread.segv_regs;
23	struct stack_frame *frame;
24
25	bp = get_frame_pointer(tsk, segv_regs);
26	sp = get_stack_pointer(tsk, segv_regs);
27
28	frame = (struct stack_frame *)bp;
29	while (((long) sp & (THREAD_SIZE-1)) != 0) {
30		addr = READ_ONCE_NOCHECK(*sp);
31		if (__kernel_text_address(addr)) {
32			reliable = 0;
33			if ((unsigned long) sp == bp + sizeof(long)) {
34				frame = frame ? frame->next_frame : NULL;
35				bp = (unsigned long)frame;
36				reliable = 1;
37			}
38			ops->address(data, addr, reliable);
39		}
40		sp++;
41	}
42}
43
44static void save_addr(void *data, unsigned long address, int reliable)
45{
46	struct stack_trace *trace = data;
47
48	if (!reliable)
49		return;
50	if (trace->nr_entries >= trace->max_entries)
51		return;
52
53	trace->entries[trace->nr_entries++] = address;
54}
55
56static const struct stacktrace_ops dump_ops = {
57	.address = save_addr
58};
59
60static void __save_stack_trace(struct task_struct *tsk, struct stack_trace *trace)
61{
62	dump_trace(tsk, &dump_ops, trace);
63}
64
65void save_stack_trace(struct stack_trace *trace)
66{
67	__save_stack_trace(current, trace);
68}
69EXPORT_SYMBOL_GPL(save_stack_trace);
70
71void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
72{
73	__save_stack_trace(tsk, trace);
74}
75EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
76