1/*
2 * arch/mips/kernel/stacktrace.c
3 *
4 * Stack trace management functions
5 *
6 *  Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
7 */
8#include <linux/sched.h>
9#include <linux/stacktrace.h>
10#include <asm/stacktrace.h>
11
12/*
13 * Save stack-backtrace addresses into a stack_trace buffer:
14 */
15static void save_raw_context_stack(struct stack_trace *trace,
16	unsigned long reg29)
17{
18	unsigned long *sp = (unsigned long *)reg29;
19	unsigned long addr;
20
21	while (!kstack_end(sp)) {
22		addr = *sp++;
23		if (__kernel_text_address(addr)) {
24			if (trace->skip > 0)
25				trace->skip--;
26			else
27				trace->entries[trace->nr_entries++] = addr;
28			if (trace->nr_entries >= trace->max_entries)
29				break;
30		}
31	}
32}
33
34static void save_context_stack(struct stack_trace *trace, struct pt_regs *regs)
35{
36	unsigned long sp = regs->regs[29];
37#ifdef CONFIG_KALLSYMS
38	unsigned long ra = regs->regs[31];
39	unsigned long pc = regs->cp0_epc;
40
41	if (raw_show_trace || !__kernel_text_address(pc)) {
42		unsigned long stack_page =
43			(unsigned long)task_stack_page(current);
44		if (stack_page && sp >= stack_page &&
45		    sp <= stack_page + THREAD_SIZE - 32)
46			save_raw_context_stack(trace, sp);
47		return;
48	}
49	do {
50		if (trace->skip > 0)
51			trace->skip--;
52		else
53			trace->entries[trace->nr_entries++] = pc;
54		if (trace->nr_entries >= trace->max_entries)
55			break;
56		pc = unwind_stack(current, &sp, pc, &ra);
57	} while (pc);
58#else
59	save_raw_context_stack(trace, sp);
60#endif
61}
62
63/*
64 * Save stack-backtrace addresses into a stack_trace buffer.
65 */
66void save_stack_trace(struct stack_trace *trace)
67{
68	struct pt_regs dummyregs;
69	struct pt_regs *regs = &dummyregs;
70
71	WARN_ON(trace->nr_entries || !trace->max_entries);
72
73	prepare_frametrace(regs);
74	save_context_stack(trace, regs);
75}
76