[S390] Simplify stack trace.
[deliverable/linux.git] / arch / s390 / kernel / stacktrace.c
CommitLineData
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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
4d284cac 14static unsigned long save_context_stack(struct stack_trace *trace,
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15 unsigned long sp,
16 unsigned long low,
17 unsigned long high)
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18{
19 struct stack_frame *sf;
20 struct pt_regs *regs;
21 unsigned long addr;
22
23 while(1) {
24 sp &= PSW_ADDR_INSN;
25 if (sp < low || sp > high)
26 return sp;
27 sf = (struct stack_frame *)sp;
28 while(1) {
29 addr = sf->gprs[8] & PSW_ADDR_INSN;
e90a2857 30 if (!trace->skip)
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31 trace->entries[trace->nr_entries++] = addr;
32 else
e90a2857 33 trace->skip--;
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34 if (trace->nr_entries >= trace->max_entries)
35 return sp;
36 low = sp;
37 sp = sf->back_chain & PSW_ADDR_INSN;
38 if (!sp)
39 break;
40 if (sp <= low || sp > high - sizeof(*sf))
41 return sp;
42 sf = (struct stack_frame *)sp;
43 }
44 /* Zero backchain detected, check for interrupt frame. */
45 sp = (unsigned long)(sf + 1);
46 if (sp <= low || sp > high - sizeof(*regs))
47 return sp;
48 regs = (struct pt_regs *)sp;
49 addr = regs->psw.addr & PSW_ADDR_INSN;
e90a2857 50 if (!trace->skip)
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51 trace->entries[trace->nr_entries++] = addr;
52 else
e90a2857 53 trace->skip--;
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54 if (trace->nr_entries >= trace->max_entries)
55 return sp;
56 low = sp;
57 sp = regs->gprs[15];
58 }
59}
60
ab1b6f03 61void save_stack_trace(struct stack_trace *trace)
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62{
63 register unsigned long sp asm ("15");
75e9de18 64 unsigned long orig_sp, new_sp;
5bdc9b44 65
75e9de18 66 orig_sp = sp & PSW_ADDR_INSN;
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67 new_sp = save_context_stack(trace, orig_sp,
68 S390_lowcore.panic_stack - PAGE_SIZE,
69 S390_lowcore.panic_stack);
ab1b6f03 70 if (new_sp != orig_sp)
5bdc9b44 71 return;
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72 new_sp = save_context_stack(trace, new_sp,
73 S390_lowcore.async_stack - ASYNC_SIZE,
74 S390_lowcore.async_stack);
ab1b6f03 75 if (new_sp != orig_sp)
5bdc9b44 76 return;
e90a2857 77 save_context_stack(trace, new_sp,
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78 S390_lowcore.thread_info,
79 S390_lowcore.thread_info + THREAD_SIZE);
5bdc9b44 80}
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