1/*
2 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Copyright (C) 2013 Richard Weinberger <richard@nod.at>
4 * Copyright (C) 2014 Google Inc., Author: Daniel Walter <dwalter@google.com>
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 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/kallsyms.h>
12#include <linux/kernel.h>
13#include <linux/sched.h>
14#include <linux/stacktrace.h>
15#include <linux/module.h>
16#include <linux/uaccess.h>
17#include <asm/stacktrace.h>
18
19void dump_trace(struct task_struct *tsk,
20		const struct stacktrace_ops *ops,
21		void *data)
22{
23	int reliable = 0;
24	unsigned long *sp, bp, addr;
25	struct pt_regs *segv_regs = tsk->thread.segv_regs;
26	struct stack_frame *frame;
27
28	bp = get_frame_pointer(tsk, segv_regs);
29	sp = get_stack_pointer(tsk, segv_regs);
30
31	frame = (struct stack_frame *)bp;
32	while (((long) sp & (THREAD_SIZE-1)) != 0) {
33		addr = *sp;
34		if (__kernel_text_address(addr)) {
35			reliable = 0;
36			if ((unsigned long) sp == bp + sizeof(long)) {
37				frame = frame ? frame->next_frame : NULL;
38				bp = (unsigned long)frame;
39				reliable = 1;
40			}
41			ops->address(data, addr, reliable);
42		}
43		sp++;
44	}
45}
46
47static void save_addr(void *data, unsigned long address, int reliable)
48{
49	struct stack_trace *trace = data;
50
51	if (!reliable)
52		return;
53	if (trace->nr_entries >= trace->max_entries)
54		return;
55
56	trace->entries[trace->nr_entries++] = address;
57}
58
59static const struct stacktrace_ops dump_ops = {
60	.address = save_addr
61};
62
63static void __save_stack_trace(struct task_struct *tsk, struct stack_trace *trace)
64{
65	dump_trace(tsk, &dump_ops, trace);
66	if (trace->nr_entries < trace->max_entries)
67		trace->entries[trace->nr_entries++] = ULONG_MAX;
68}
69
70void save_stack_trace(struct stack_trace *trace)
71{
72	__save_stack_trace(current, trace);
73}
74EXPORT_SYMBOL_GPL(save_stack_trace);
75
76void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
77{
78	__save_stack_trace(tsk, trace);
79}
80EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
81