1/*
2 * Stack trace management functions
3 *
4 *  Copyright (C) 2009 Helge Deller <deller@gmx.de>
5 *  based on arch/x86/kernel/stacktrace.c by Ingo Molnar <mingo@redhat.com>
6 *  and parisc unwind functions by Randolph Chung <tausq@debian.org>
7 *
8 *  TODO: Userspace stacktrace (CONFIG_USER_STACKTRACE_SUPPORT)
9 */
10#include <linux/module.h>
11#include <linux/stacktrace.h>
12
13#include <asm/unwind.h>
14
15static void dump_trace(struct task_struct *task, struct stack_trace *trace)
16{
17	struct unwind_frame_info info;
18
19	/* initialize unwind info */
20	if (task == current) {
21		unsigned long sp;
22		struct pt_regs r;
23HERE:
24		asm volatile ("copy %%r30, %0" : "=r"(sp));
25		memset(&r, 0, sizeof(struct pt_regs));
26		r.iaoq[0] = (unsigned long)&&HERE;
27		r.gr[2] = (unsigned long)__builtin_return_address(0);
28		r.gr[30] = sp;
29		unwind_frame_init(&info, task, &r);
30	} else {
31		unwind_frame_init_from_blocked_task(&info, task);
32	}
33
34	/* unwind stack and save entries in stack_trace struct */
35	trace->nr_entries = 0;
36	while (trace->nr_entries < trace->max_entries) {
37		if (unwind_once(&info) < 0 || info.ip == 0)
38			break;
39
40		if (__kernel_text_address(info.ip))
41			trace->entries[trace->nr_entries++] = info.ip;
42	}
43}
44
45
46/*
47 * Save stack-backtrace addresses into a stack_trace buffer.
48 */
49void save_stack_trace(struct stack_trace *trace)
50{
51	dump_trace(current, trace);
52	if (trace->nr_entries < trace->max_entries)
53		trace->entries[trace->nr_entries++] = ULONG_MAX;
54}
55EXPORT_SYMBOL_GPL(save_stack_trace);
56
57void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
58{
59	dump_trace(tsk, trace);
60	if (trace->nr_entries < trace->max_entries)
61		trace->entries[trace->nr_entries++] = ULONG_MAX;
62}
63EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
64