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                                         int savesched)
  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 (!trace->skip)
  32                                 trace->entries[trace->nr_entries++] = addr;
  33                         else
  34                                 trace->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 (savesched || !in_sched_functions(addr)) {
  52                         if (!trace->skip)
  53                                 trace->entries[trace->nr_entries++] = addr;
  54                         else
  55                                 trace->skip--;
  56                 }
  57                 if (trace->nr_entries >= trace->max_entries)
  58                         return sp;
  59                 low = sp;
  60                 sp = regs->gprs[15];
  61         }
  62 }
  63
  64 void save_stack_trace(struct stack_trace *trace)
  65 {
  66         register unsigned long sp asm ("15");
  67         unsigned long orig_sp, new_sp;
  68
  69         orig_sp = sp & PSW_ADDR_INSN;
  70         new_sp = save_context_stack(trace, orig_sp,
  71                                     S390_lowcore.panic_stack - PAGE_SIZE,
  72                                     S390_lowcore.panic_stack, 1);
  73         if (new_sp != orig_sp)
  74                 return;
  75         new_sp = save_context_stack(trace, new_sp,
  76                                     S390_lowcore.async_stack - ASYNC_SIZE,
  77                                     S390_lowcore.async_stack, 1);
  78         if (new_sp != orig_sp)
  79                 return;
  80         save_context_stack(trace, new_sp,
  81                            S390_lowcore.thread_info,
  82                            S390_lowcore.thread_info + THREAD_SIZE, 1);
  83 }
  84 EXPORT_SYMBOL_GPL(save_stack_trace);
  85
  86 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
  87 {
  88         unsigned long sp, low, high;
  89
  90         sp = tsk->thread.ksp & PSW_ADDR_INSN;
  91         low = (unsigned long) task_stack_page(tsk);
  92         high = (unsigned long) task_pt_regs(tsk);
  93         save_context_stack(trace, sp, low, high, 0);
  94         if (trace->nr_entries < trace->max_entries)
  95                 trace->entries[trace->nr_entries++] = ULONG_MAX;
  96 }
  97 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);