git.oblomov.eu Git - linux-2.6/blob - 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
  14 static unsigned long save_context_stack(struct stack_trace *trace,
  15                                         unsigned long sp,
  16                                         unsigned long low,
  17                                         unsigned long high)
  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;
  30                         if (!trace->skip)
  31                                 trace->entries[trace->nr_entries++] = addr;
  32                         else
  33                                 trace->skip--;
  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;
  50                 if (!trace->skip)
  51                         trace->entries[trace->nr_entries++] = addr;
  52                 else
  53                         trace->skip--;
  54                 if (trace->nr_entries >= trace->max_entries)
  55                         return sp;
  56                 low = sp;
  57                 sp = regs->gprs[15];
  58         }
  59 }
  60
  61 void save_stack_trace(struct stack_trace *trace)
  62 {
  63         register unsigned long sp asm ("15");
  64         unsigned long orig_sp, new_sp;
  65
  66         orig_sp = sp & PSW_ADDR_INSN;
  67         new_sp = save_context_stack(trace, orig_sp,
  68                                     S390_lowcore.panic_stack - PAGE_SIZE,
  69                                     S390_lowcore.panic_stack);
  70         if (new_sp != orig_sp)
  71                 return;
  72         new_sp = save_context_stack(trace, new_sp,
  73                                     S390_lowcore.async_stack - ASYNC_SIZE,
  74                                     S390_lowcore.async_stack);
  75         if (new_sp != orig_sp)
  76                 return;
  77         save_context_stack(trace, new_sp,
  78                            S390_lowcore.thread_info,
  79                            S390_lowcore.thread_info + THREAD_SIZE);
  80 }