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
  15 static 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
  65 void 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 }
  85 EXPORT_SYMBOL_GPL(save_stack_trace);
  86
  87 void 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 }
  98 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);