arch/s390/kernel/stacktrace.c

   1 /*
   2  * Stack trace management functions
   3  *
   4  *  Copyright IBM Corp. 2006
   5  *  Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
   6  */
   7
   8 #include <linux/sched.h>
   9 #include <linux/stacktrace.h>
  10 #include <linux/kallsyms.h>
  11 #include <linux/module.h>
  12
  13 static unsigned long save_context_stack(struct stack_trace *trace,
  14                                         unsigned long sp,
  15                                         unsigned long low,
  16                                         unsigned long high,
  17                                         int savesched)
  18 {
  19         struct stack_frame *sf;
  20         struct pt_regs *regs;
  21         unsigned long addr;
  22
  23         while(1) {
  24                 if (sp < low || sp > high)
  25                         return sp;
  26                 sf = (struct stack_frame *)sp;
  27                 while(1) {
  28                         addr = sf->gprs[8];
  29                         if (!trace->skip)
  30                                 trace->entries[trace->nr_entries++] = addr;
  31                         else
  32                                 trace->skip--;
  33                         if (trace->nr_entries >= trace->max_entries)
  34                                 return sp;
  35                         low = sp;
  36                         sp = sf->back_chain;
  37                         if (!sp)
  38                                 break;
  39                         if (sp <= low || sp > high - sizeof(*sf))
  40                                 return sp;
  41                         sf = (struct stack_frame *)sp;
  42                 }
  43                 /* Zero backchain detected, check for interrupt frame. */
  44                 sp = (unsigned long)(sf + 1);
  45                 if (sp <= low || sp > high - sizeof(*regs))
  46                         return sp;
  47                 regs = (struct pt_regs *)sp;
  48                 addr = regs->psw.addr;
  49                 if (savesched || !in_sched_functions(addr)) {
  50                         if (!trace->skip)
  51                                 trace->entries[trace->nr_entries++] = addr;
  52                         else
  53                                 trace->skip--;
  54                 }
  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)
  63 {
  64         register unsigned long sp asm ("15");
  65         unsigned long orig_sp, new_sp, frame_size;
  66
  67         frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
  68         orig_sp = sp;
  69         new_sp = save_context_stack(trace, orig_sp,
  70                         S390_lowcore.panic_stack + frame_size - PAGE_SIZE,
  71                         S390_lowcore.panic_stack + frame_size, 1);
  72         if (new_sp != orig_sp)
  73                 return;
  74         new_sp = save_context_stack(trace, new_sp,
  75                         S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
  76                         S390_lowcore.async_stack + frame_size, 1);
  77         if (new_sp != orig_sp)
  78                 return;
  79         save_context_stack(trace, new_sp,
  80                            S390_lowcore.thread_info,
  81                            S390_lowcore.thread_info + THREAD_SIZE, 1);
  82 }
  83 EXPORT_SYMBOL_GPL(save_stack_trace);
  84
  85 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
  86 {
  87         unsigned long sp, low, high;
  88
  89         sp = tsk->thread.ksp;
  90         if (tsk == current) {
  91                 /* Get current stack pointer. */
  92                 asm volatile("la %0,0(15)" : "=a" (sp));
  93         }
  94         low = (unsigned long) task_stack_page(tsk);
  95         high = (unsigned long) task_pt_regs(tsk);
  96         save_context_stack(trace, sp, low, high, 0);
  97         if (trace->nr_entries < trace->max_entries)
  98                 trace->entries[trace->nr_entries++] = ULONG_MAX;
  99 }
 100 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);