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 inline unsigned long save_context_stack(struct stack_trace *trace,
  15                                                unsigned int *skip,
  16                                                unsigned long sp,
  17                                                unsigned long low,
  18                                                unsigned long high)
  19 {
  20         struct stack_frame *sf;
  21         struct pt_regs *regs;
  22         unsigned long addr;
  23
  24         while(1) {
  25                 sp &= PSW_ADDR_INSN;
  26                 if (sp < low || sp > high)
  27                         return sp;
  28                 sf = (struct stack_frame *)sp;
  29                 while(1) {
  30                         addr = sf->gprs[8] & PSW_ADDR_INSN;
  31                         if (!(*skip))
  32                                 trace->entries[trace->nr_entries++] = addr;
  33                         else
  34                                 (*skip)--;
  35                         if (trace->nr_entries >= trace->max_entries)
  36                                 return sp;
  37                         low = sp;
  38                         sp = sf->back_chain & PSW_ADDR_INSN;
  39                         if (!sp)
  40                                 break;
  41                         if (sp <= low || sp > high - sizeof(*sf))
  42                                 return sp;
  43                         sf = (struct stack_frame *)sp;
  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                 addr = regs->psw.addr & PSW_ADDR_INSN;
  51                 if (!(*skip))
  52                         trace->entries[trace->nr_entries++] = addr;
  53                 else
  54                         (*skip)--;
  55                 if (trace->nr_entries >= trace->max_entries)
  56                         return sp;
  57                 low = sp;
  58                 sp = regs->gprs[15];
  59         }
  60 }
  61
  62 void save_stack_trace(struct stack_trace *trace, struct task_struct *task)
  63 {
  64         register unsigned long sp asm ("15");
  65         unsigned long orig_sp;
  66
  67         sp &= PSW_ADDR_INSN;
  68         orig_sp = sp;
  69
  70         sp = save_context_stack(trace, &trace->skip, sp,
  71                                 S390_lowcore.panic_stack - PAGE_SIZE,
  72                                 S390_lowcore.panic_stack);
  73         if ((sp != orig_sp) && !trace->all_contexts)
  74                 return;
  75         sp = save_context_stack(trace, &trace->skip, sp,
  76                                 S390_lowcore.async_stack - ASYNC_SIZE,
  77                                 S390_lowcore.async_stack);
  78         if ((sp != orig_sp) && !trace->all_contexts)
  79                 return;
  80         if (task)
  81                 save_context_stack(trace, &trace->skip, sp,
  82                                    (unsigned long) task_stack_page(task),
  83                                    (unsigned long) task_stack_page(task) + THREAD_SIZE);
  84         else
  85                 save_context_stack(trace, &trace->skip, sp,
  86                                    S390_lowcore.thread_info,
  87                                    S390_lowcore.thread_info + THREAD_SIZE);
  88         return;
  89 }