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   1 /**
   2  * arch/s390/oprofile/backtrace.c
   3  *
   4  * S390 Version
   5  *   Copyright (C) 2005 IBM Corporation, IBM Deutschland Entwicklung GmbH.
   6  *   Author(s): Andreas Krebbel <Andreas.Krebbel@de.ibm.com>
   7  */
   8
   9 #include <linux/oprofile.h>
  10
  11 #include <asm/processor.h> /* for struct stack_frame */
  12
  13 static unsigned long
  14 __show_trace(unsigned int *depth, unsigned long sp,
  15              unsigned long low, unsigned long high)
  16 {
  17         struct stack_frame *sf;
  18         struct pt_regs *regs;
  19
  20         while (*depth) {
  21                 sp = sp & PSW_ADDR_INSN;
  22                 if (sp < low || sp > high - sizeof(*sf))
  23                         return sp;
  24                 sf = (struct stack_frame *) sp;
  25                 (*depth)--;
  26                 oprofile_add_trace(sf->gprs[8] & PSW_ADDR_INSN);
  27
  28                 /* Follow the backchain.  */
  29                 while (*depth) {
  30                         low = sp;
  31                         sp = sf->back_chain & PSW_ADDR_INSN;
  32                         if (!sp)
  33                                 break;
  34                         if (sp <= low || sp > high - sizeof(*sf))
  35                                 return sp;
  36                         sf = (struct stack_frame *) sp;
  37                         (*depth)--;
  38                         oprofile_add_trace(sf->gprs[8] & PSW_ADDR_INSN);
  39
  40                 }
  41
  42                 if (*depth == 0)
  43                         break;
  44
  45                 /* Zero backchain detected, check for interrupt frame.  */
  46                 sp = (unsigned long) (sf + 1);
  47                 if (sp <= low || sp > high - sizeof(*regs))
  48                         return sp;
  49                 regs = (struct pt_regs *) sp;
  50                 (*depth)--;
  51                 oprofile_add_trace(sf->gprs[8] & PSW_ADDR_INSN);
  52                 low = sp;
  53                 sp = regs->gprs[15];
  54         }
  55         return sp;
  56 }
  57
  58 void s390_backtrace(struct pt_regs * const regs, unsigned int depth)
  59 {
  60         unsigned long head;
  61         struct stack_frame* head_sf;
  62
  63         if (user_mode (regs))
  64                 return;
  65
  66         head = regs->gprs[15];
  67         head_sf = (struct stack_frame*)head;
  68
  69         if (!head_sf->back_chain)
  70                 return;
  71
  72         head = head_sf->back_chain;
  73
  74         head = __show_trace(&depth, head, S390_lowcore.async_stack - ASYNC_SIZE,
  75                             S390_lowcore.async_stack);
  76
  77         __show_trace(&depth, head, S390_lowcore.thread_info,
  78                      S390_lowcore.thread_info + THREAD_SIZE);
  79 }