Root/arch/s390/kernel/stacktrace.c

1/*
2 * arch/s390/kernel/stacktrace.c
3 *
4 * Stack trace management functions
5 *
6 * Copyright (C) IBM Corp. 2006
7 * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
8 */
9
10#include <linux/sched.h>
11#include <linux/stacktrace.h>
12#include <linux/kallsyms.h>
13#include <linux/module.h>
14
15static unsigned long save_context_stack(struct stack_trace *trace,
16                    unsigned long sp,
17                    unsigned long low,
18                    unsigned long high,
19                    int savesched)
20{
21    struct stack_frame *sf;
22    struct pt_regs *regs;
23    unsigned long addr;
24
25    while(1) {
26        sp &= PSW_ADDR_INSN;
27        if (sp < low || sp > high)
28            return sp;
29        sf = (struct stack_frame *)sp;
30        while(1) {
31            addr = sf->gprs[8] & PSW_ADDR_INSN;
32            if (!trace->skip)
33                trace->entries[trace->nr_entries++] = addr;
34            else
35                trace->skip--;
36            if (trace->nr_entries >= trace->max_entries)
37                return sp;
38            low = sp;
39            sp = sf->back_chain & PSW_ADDR_INSN;
40            if (!sp)
41                break;
42            if (sp <= low || sp > high - sizeof(*sf))
43                return sp;
44            sf = (struct stack_frame *)sp;
45        }
46        /* Zero backchain detected, check for interrupt frame. */
47        sp = (unsigned long)(sf + 1);
48        if (sp <= low || sp > high - sizeof(*regs))
49            return sp;
50        regs = (struct pt_regs *)sp;
51        addr = regs->psw.addr & PSW_ADDR_INSN;
52        if (savesched || !in_sched_functions(addr)) {
53            if (!trace->skip)
54                trace->entries[trace->nr_entries++] = addr;
55            else
56                trace->skip--;
57        }
58        if (trace->nr_entries >= trace->max_entries)
59            return sp;
60        low = sp;
61        sp = regs->gprs[15];
62    }
63}
64
65void save_stack_trace(struct stack_trace *trace)
66{
67    register unsigned long sp asm ("15");
68    unsigned long orig_sp, new_sp;
69
70    orig_sp = sp & PSW_ADDR_INSN;
71    new_sp = save_context_stack(trace, orig_sp,
72                    S390_lowcore.panic_stack - PAGE_SIZE,
73                    S390_lowcore.panic_stack, 1);
74    if (new_sp != orig_sp)
75        return;
76    new_sp = save_context_stack(trace, new_sp,
77                    S390_lowcore.async_stack - ASYNC_SIZE,
78                    S390_lowcore.async_stack, 1);
79    if (new_sp != orig_sp)
80        return;
81    save_context_stack(trace, new_sp,
82               S390_lowcore.thread_info,
83               S390_lowcore.thread_info + THREAD_SIZE, 1);
84}
85EXPORT_SYMBOL_GPL(save_stack_trace);
86
87void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
88{
89    unsigned long sp, low, high;
90
91    sp = tsk->thread.ksp & PSW_ADDR_INSN;
92    low = (unsigned long) task_stack_page(tsk);
93    high = (unsigned long) task_pt_regs(tsk);
94    save_context_stack(trace, sp, low, high, 0);
95    if (trace->nr_entries < trace->max_entries)
96        trace->entries[trace->nr_entries++] = ULONG_MAX;
97}
98EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
99

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